JP7611690B2 - Recording device and recording control method - Google Patents

Description

The present invention relates to a recording device and a recording control method, and in particular to a recording device and a recording control method that records an image by, for example, heating a recording medium on which color-developing layers of different colors are superimposed using a heating element.

Until now, monochrome printing using thermal paper and color printing using ink ribbons have been widely used in recording with thermal printheads. Meanwhile, in recent years, color recording using paper with multiple color-developing layers has been proposed and has become popular as a simple method of printing photographs, etc. Each of the multiple color-developing layers requires a different heating temperature and heating time to develop color, and a color image is recorded by utilizing these differences to develop a specific color-developing layer (see Patent Documents 1 and 2).

Special Publication No. 2013-506582 Patent No. 4677431

However, in the above conventional example, the pulse width of the head drive pulse used to color each color-producing layer was fixed, so multiple pulse applications were required to produce a specific color with a high color-producing temperature, resulting in the problem of long heating times.

The present invention has been made in consideration of the above-mentioned conventional examples, and aims to provide a recording device and a recording control method that can achieve highly colored recording while shortening the heating time required to produce a specific color.

To achieve the above objective, the recording device of the present invention has the following configuration.

That is, a recording device for heating a sheet-shaped recording medium on which a plurality of color-forming layers corresponding to a plurality of colors are superimposed, and causing a desired one of the plurality of color-forming layers to develop color to form an image on the recording medium, the recording device including: an input means for inputting image data from a host device; a recording head having a plurality of heating elements; a drive means for driving each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color-forming layer and a second pulse applied after the first pulse for developing the predetermined color-forming layer; and, when a specific color is to be developed, at least one of lengthening the pulse width of the first pulse and increasing the number of times the second pulse is applied is applied to the specific color. and a pulse control means for controlling the recording medium so as not to cause other color-forming layers not used in the reproduction of the image to develop color , the recording medium having, in order from the side where the multiple heating elements of the recording head contact, a first color-forming layer that develops yellow (Y), a second color-forming layer that develops magenta (M), and a third color-forming layer that develops cyan (C), the driving means drives the recording head based on image data input by the input means to cause the first color-forming layer, the second color-forming layer, and the third color-forming layer to develop color in that order, forming an image on the recording medium, and the specific color is a color formed by color development only of the second color-forming layer, color development only of the third color-forming layer, and color development by the second color-forming layer and the third color-forming layer .

From another aspect of the present invention, there is provided a method for controlling a recording device having an input means for inputting image data from a host device, the method comprising: heating a sheet-shaped recording medium having a plurality of color-forming layers superposed thereon, the color-forming layers corresponding to a plurality of colors and each coloring in response to heating, by a recording head having a plurality of heating elements, to cause a desired color-forming layer among the plurality of color-forming layers to develop a color, and forming an image on the recording medium, the method comprising the steps of: driving each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color-forming layer, and a second pulse applied after the first pulse for causing the predetermined color-forming layer to develop a color, the method comprising at least one of increasing a pulse width of the first pulse and increasing the number of times the second pulse is applied, when a specific color is to be developed, The recording medium has a control step of controlling any one of the color layers so as not to cause other color layers not used in reproducing the specific color to color, and the recording medium has, in order from the side where the multiple heating elements of the recording head contact, a first color layer that colors yellow (Y), a second color layer that colors magenta (M), and a third color layer that colors cyan (C), and the recording head is driven based on image data input by the input means to cause the first color layer, the second color layer, and the third color layer to color in that order to form an image on the recording medium, and the specific color is a color formed by coloring only the second color layer, coloring only the third color layer, and coloring by the second color layer and the third color layer .

From another aspect of the present invention, there is provided a recording apparatus for heating a sheet-shaped recording medium having a plurality of superposed color forming layers, each of which corresponds to a plurality of colors and develops color in response to heating, to cause a desired one of the plurality of color forming layers to develop color, thereby forming an image on the recording medium, the recording apparatus comprising: a recording head having a plurality of heat generating elements; drive means for driving each of the plurality of heat generating elements of the recording head using a first pulse for preheating a predetermined color forming layer and a second pulse applied after the first pulse for developing color in the predetermined color forming layer; transport means for transporting the recording medium in a first direction relative to the recording head; and a driving means for driving a first pixel located in a non-image forming area of the recording medium using the first pulse, and a driving means for driving a second pixel located in an image forming area of the recording medium using the second pulse. and a control means for controlling the driving means to use the second pulse for a second pixel that is recorded after the first pixel , wherein the control means at least either changes a duty ratio of the first pulse used at the position of the first pixel or changes an application time of the first pulse depending on whether the color-producing layer that is caused to produce color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer based on image data, and when there are a plurality of desired color-producing layers, the control means reduces the duty ratio of the first pulse or shortens the application time of the first pulse in order to preheat a color-producing layer that is located deep inside .

From another aspect of the present invention, there is provided a method for controlling a recording device that uses a recording head having a plurality of heating elements to heat a sheet-shaped recording medium having a plurality of superposed color forming layers that correspond to a plurality of colors and develop color in response to heating, thereby forming an image on the recording medium by causing a desired color forming layer among the plurality of color forming layers to develop color, the method comprising the steps of: driving each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color forming layer and a second pulse that is applied after the first pulse and causes the predetermined color forming layer to develop color, the method comprising the steps of: driving a first pixel located in a non-image forming area of the recording medium using the first pulse; The recording control method includes controlling to use the second pulse in a second pixel recorded after the first pixel, and at least one of changing a duty ratio of the first pulse used at the position of the first pixel or changing an application time of the first pulse depending on whether the color-producing layer to be caused to produce color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer based on input image data, and when there are a plurality of desired color-producing layers, reducing the duty ratio of the first pulse or shortening the application time of the first pulse in order to preheat a color-producing layer located deep inside .

The present invention has the effect of realizing high-color recording while shortening the heating time required to develop a specific color. It also improves color development at the ends where image formation begins.

1 is a side cross-sectional view showing a schematic configuration of a recording apparatus according to a typical embodiment of the present invention. 2 is a block diagram showing a control configuration of the printing apparatus shown in FIG. 1 and a host device connected thereto. 2 is a side cross-sectional view showing a detailed configuration of a print head mounted on the printing apparatus shown in FIG. 1 . 4 is a side cross-sectional view showing a detailed structure of an ink ribbon heated by the recording head shown in FIG. 3. 4 is a diagram for explaining the recording principle by the recording head shown in FIG. 3. 11 is a flowchart showing a conventional recording process as a comparative example. 11A and 11B are diagrams for explaining control of a conventional example of a print head as a comparative example. 5 is a flowchart showing the process of the printing apparatus and the host PC when a print service according to the first embodiment is executed in the printing system. 5A to 5C are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to the process of the first embodiment. 5 is a flowchart showing image processing for generating a heating pulse to drive a printhead according to the first embodiment. 11A to 11C are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a first modified example of the first embodiment. 13A to 13C are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a second modified example of the first embodiment. 13A to 13C are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a third modified example of the first embodiment. 10 is a flowchart showing the process of the printing apparatus and the host PC when a high-speed print service according to the second embodiment is executed in the printing system. 13A and 13B are diagrams illustrating an example of a heating pulse applied to a recording head of a recording device according to the process of the second embodiment. 13A and 13B are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a first modified example of the second embodiment. 13A and 13B are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a second modified example of the second embodiment. 13A and 13B are diagrams illustrating an example of a heating pulse applied to a print head of a printing apparatus according to a third modified example of the second embodiment. 1 is a diagram showing the relationship between an image I formed on an infrared imaging member 10 and a conveying direction D of the infrared imaging member 10. FIG. 13A and 13B are diagrams showing examples of heating pulses applied to a recording head of a recording device according to a third embodiment. 21 is a diagram for explaining the application timing of a preheat pulse to a previous pixel region IW different from that in FIG. 20. FIG. 10 is a flowchart showing image processing for generating a heating pulse to drive a printhead according to a third embodiment. 21 is a diagram for explaining the application timing of a preheat pulse to a immediately preceding pixel region IW different from that in FIG. 20. FIG. FIG. 10 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 9 are used for application timings p0 to p8 of the image start end IA. FIG. 16 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 15 are used for application timings p0 to p8 of the image start end IA. 13 is a diagram illustrating a correction table that stores pixel values of the immediately preceding pixel region IW after correction according to pixel values of the image start end IA when the immediately preceding pixel region IW is a white pixel. FIG. 13 is a flowchart showing image processing for generating a heating pulse to drive a printhead according to a fourth embodiment. 13 is a diagram showing preheat instructions according to combinations of specific colors in the immediately preceding pixel area IW and the image start edge IA, and the numbers of the table groups to be used. FIG. FIG. 13 is a diagram illustrating a heating pulse for a combination of specific colors of pixels on the nth line and pixels on the (n+1)th line. FIG. 13 is a diagram showing an example of a preheat pulse and a subsequent heating pulse when the thermal history is high. 13 is a diagram showing an example in which preheating for an image start end IA is performed using only a preheat pulse for a previous pixel area IW. FIG.

The preferred embodiments of the present invention will be described more specifically and in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations will be omitted.

<Outline of the recording device (Figs. 1 to 3)>
FIG. 1 is a side cross-sectional view showing a schematic configuration of a recording apparatus according to a typical embodiment of the present invention.

As shown in FIG. 1, the recording device 40 includes a recording head 30, a storage section 41, a transport roller 42, a platen 43, and an outlet 44. The storage section 41 can store multiple sheet-like recording media 10, and the recording media 10 can be replenished by opening and closing a cover (not shown). During printing, the recording medium 10 is transported to the bottom of the recording head 30 by the transport roller 42, and after an image is formed between the platen 43 and the recording head 30, it is discharged from the outlet 44 and printing is completed.

Figure 2 is a block diagram showing the control configuration of a recording system that is composed of the recording device shown in Figure 1 and a host device connected to it. As shown in Figure 2, this recording system is composed of the recording device 40 shown in Figure 1 and a personal computer (host PC) 50 that serves as the host device.

The host PC 50 includes a CPU 501, a RAM 502, a HDD 503, a data transfer interface (I/F) 504, a keyboard/mouse interface (I/F) 505, and a display interface (I/F) 506.

The CPU 501 executes processing according to the programs stored in the HDD 503 and RAM 502. The RAM 502 is a volatile storage and temporarily stores programs and data. The HDD 503 is a non-volatile storage and similarly stores programs and data. The data transfer I/F 504 controls the transmission and reception of data with the recording device 40. This data transmission and reception transfer method can be a wired connection such as USB, IEEE 1394, or LAN, or a wireless connection such as Bluetooth (registered trademark) or WiFi. The keyboard/mouse (registered trademark) I/F 505 is an interface that controls a UI (user interface) such as a keyboard or mouse, and a user can input information to the host PC via this. The display I/F 506 controls the display on a display (not shown).

On the other hand, the recording device 40 includes a CPU 401, a RAM 402, a ROM 403, a data transfer interface (I/F) 404, a head controller 405, and an image processing accelerator 406.

The CPU 401 executes the processing of each embodiment described below in accordance with the programs stored in the ROM 403 and the RAM 402. The RAM 402 is a volatile storage and temporarily stores programs and data. The ROM 403 is a non-volatile storage and stores table data and programs used in the processing of each embodiment described below. The data transfer I/F 404 controls data transmission and reception with the PC 50.

The head controller 405 controls the heating operation (described later) of the print head 30 based on the print data. Specifically, the head controller 405 is configured to read the control parameters and print data from a specified address in the RAM 402. In other words, when the CPU 401 writes the control parameters and print data to a specified address in the RAM 402, the head controller 405 starts processing and performs the print head heating operation.

The image processing accelerator 406 is configured with hardware and executes image processing faster than the CPU 401. Specifically, the image processing accelerator 406 is configured to read parameters and data required for image processing from a specified address in the RAM 402. Then, when the CPU 401 writes the above parameters and data to a specified address in the RAM 402, the image processing accelerator 406 is started and the specified image processing is executed.

Note that the image processing accelerator 406 is not necessarily a required component, and depending on the specifications of the recording device, the above table parameter creation process and image processing may be performed solely by the CPU 401.

<Outline of the configuration of the recording head (FIG. 3)>
FIG. 3 is a side cross-sectional view showing the configuration of a recording head and the state of the contact area between the recording head and a recording medium.

The recording head 30 comprises a glaze 32 on a substrate 31. The glaze 32 may further comprise a "convex glaze" 33. The resistor 34 is disposed on the surface of the convex glaze 33 if it is present, or on the surface of the flat glaze 32 if it is not present. It is preferable that a protective film layer is formed on the resistor 34, the glaze 32, and the convex glaze 33. The combination of the glaze 32 and the convex glaze 33, which are generally made of the same material, is hereinafter referred to as the "glaze of the recording head".

The substrate 31 is in contact with a heat sink 35 and is cooled using a fan or the like. The recording medium 10 is in contact with the glaze of the recording head, which is generally of a length substantially greater than the length of the actual heating resistor. The resistor 34 is an electrothermal conversion element (heater or heating element) that generates heat when a current is supplied to it. A typical resistor has a length of about 120 μm in the transport direction of the recording medium 10, but the thermal contact area of the recording medium with the glaze of a typical recording head is 200 μm or more.

<Outline of recording principle (Figs. 4 and 5)>
4 is a cross-sectional view showing the structure of a sheet-like recording medium for use in image formation using infrared rays as a heat source. As described in detail below, the recording medium 10 is also called an infrared imaging member because it is made up of multiple color-forming layers that are heated and colored by heat rays (infrared rays) radiated from a resistor 34 when an electric current is supplied to the resistor, and a full-color image is formed by the coloring of these color-forming layers. Therefore, in this sense, the recording medium 10 will be referred to as an infrared imaging member in the following description.

As shown in FIG. 4, the infrared imaging member 10 includes image forming layers 14, 16, 18, spacer layers 15, 17, and a protective film layer 13 formed on a light-reflective substrate 12. The image forming layers 14, 16, 18 are typically yellow (Y), magenta (M), and cyan (C), respectively, during full-color printing, but may be other color combinations.

Each image-forming layer is initially colorless, but when each layer is heated to a specific temperature called the activation temperature, it becomes colored. The order of the colors of the image-forming layers can be selected arbitrarily. One preferred color order is as described above. Another preferred order is that the three image-forming layers 14, 16, and 18 are cyan (C), magenta (M), and yellow (Y), respectively. Here, an example is described in the above-mentioned order of yellow (Y), magenta (M), and cyan (C).

Spacer layer 15 is preferably thinner than spacer layer 17, unless the materials comprising both layers have substantially the same thermal diffusivity. The function of the spacer layer is to control the thermal diffusion within the thermal imaging member 10. Preferably, spacer layer 17 is at least four times thicker than spacer layer 15 if it is composed of the same material. All layers disposed on substrate 12 are substantially transparent prior to imaging. If substrate 12 is a reflective color (e.g., white), the color image formed on thermal imaging member 10 is viewed through overcoat layer 13 against the reflective background provided by substrate 12. Because the layers disposed on substrate 12 are transparent, the combination of colors formed on each imaging layer is visible.

Although the three image-forming layers 14, 16, and 18 of the thermal imaging member 10 are disposed on the same side of the substrate 12, some of the image-forming layers may be disposed on opposite sides of the substrate 12.

The imaging layers 14, 16, 18 are processed at least in part independently by the variation of two adjustable parameters, namely temperature and time. These parameters are adjustable, and by selecting the temperature of the recording head and the period of time during which the infrared imaging member is heated, an image is formed in the desired imaging layer.

Here, each of the image-forming layers 14, 16, 18 is treated by heating while the recording head 30 is in contact with the top layer of the member, i.e., the overcoat layer 13 of the thermal imaging member 10. The activation temperature (Ta3) of the image-forming layer 14 (the third layer counting from the substrate 12 and the image-forming layer closest to the surface of the thermal imaging member 10) is greater than the activation temperature (Ta2) of the image-forming layer 16, which in turn is greater than the activation temperature (Ta1) of the image-forming layer 18.

The heating of the image-forming layers at greater distances from the recording head 30 is delayed by the time required for the heat to diffuse through the spacer layers to those layers. This heating delay ensures that the image-forming layers closer to the recording head do not activate the image-forming layers below them, even though their activation temperatures are substantially higher than the activation temperatures of the lower image-forming layers (layers further from the recording head), and are allowed to heat above their activation temperatures. Thus, when processing the top image-forming layer 14, the recording head 30 briefly heats to a relatively high temperature, which insufficiently heats either of the image-forming layers 16, 18, and these layers are not activated.

To activate only the imaging layer closer to the substrate 12 (in this case, imaging layer 16 or 18), heat is applied for a long enough period of time below the activation temperature of the imaging layer further from the substrate 12. In this way, if the lower imaging layer is activated, the higher imaging layer is not activated.

Heating of the thermal imaging member 10 is preferably accomplished using the recording head 30, although any method of applying controlled heat to the thermal imaging member may be used. For example, any known means may be used, such as using a modulated light source (e.g., a laser light source).

Figure 5 is a diagram explaining the heating temperature and time of the recording head required to process the three image forming layers shown in Figure 4.

5, the vertical axis represents the heating temperature at the surface of the infrared imaging member 10 in contact with the recording head 30, and the horizontal axis represents the heating time. Region 21 (relatively high recording head temperature and relatively short heating time) provides imaging of the image-forming layer 14, region 22 (intermediate recording head temperature and intermediate heating time) provides imaging of the image-forming layer 16, and region 23 (relatively low recording head temperature and relatively long heating time) provides imaging of the image-forming layer 18. The time required to image the image-forming layer 18 is substantially longer than the time required to image the image-forming layer 14.

The activation temperature selected for the imaging layers is generally within the range of about 90° C. to about 300° C. The activation temperature (Ta1) of the imaging layer 18 is preferably as consistently low as possible for thermal stability of the infrared imaging member during shipping and storage, and is preferably about 100° C. or higher. The activation temperature (Ta3) of the imaging layer 14 is preferably consistently low for activation of the imaging layers 16, 18 by heating through this layer without activation by the heating method of this embodiment, and is preferably about 200° C. or higher. The activation temperature (Ta2) of the imaging layer 16 is preferably between about 140° C. to about 180° C., with Ta1<Ta2<Ta3.
The print head 30 used herein includes an array of resistors arranged linearly so that the resistors extend across substantially the entire width of the image (perpendicular to the direction of transport of the thermal imaging member).

Note that the recording width of the recording head may be shorter than the width of the image, in which case the recording head is configured to be moved relative to the thermal imaging member 10 or used in conjunction with other recording heads to process the entire width of the image.

By supplying current to these resistors, heating pulses are provided while the thermal imaging member is imaged as it is transported in a direction perpendicular to the direction of the resistors in the recording head. The time for which the thermal imaging member 10 is heated by the recording head 30 typically ranges from about 0.001 to about 100 milliseconds per line of the image, with an upper limit reasonably set by the image print time, and a lower limit defined by electronic circuitry constraints. The dot spacing of the formed image typically ranges from 100 to 600 lines per inch in both the direction of transport and perpendicular to the direction of transport of the thermal imaging member 10, and may be spaced differently in each direction.

The recording device described above is a type of thermal printer, and the recording method it uses is also called the ZINK (Zero Ink) method or Zero Ink technology (registered trademark).

To emphasize the effects of Example 1, we will first explain a conventional recording method as a comparative example, and then explain this Example.

Explanation of Comparative Example (FIGS. 6 and 7)
Fig. 6 is a flow chart showing the processing of the recording device 40 and the host PC 50 when a conventional print service is executed in the above-mentioned recording system. In Fig. 6, steps S601, S602, and S604-S606 show the processing of the host PC 50, and steps S611-S614 and S616-S617 show the processing of the recording device 40. Also, as shown in Fig. 6, when a user desires to print, the processing of the host PC 50 starts, and in response, the processing of the recording device 40 starts. Therefore, in step S611, the recording device 40 confirms that it is capable of printing, starts the print service, and is in a print preparation complete state (Ready).

In this state, when the host PC 50 executes print service Discovery in step S601, the recording device 40 responds to that Discovery in step S612, notifying the recording device 40 that it is a device that can provide print services. Next, in step S602, the host PC 50 obtains print capability information. Basically, it requests the print capability information from the recording device 40, and in response in step S614, the recording device 40 notifies the recording device 40 of information on the print services it can provide.

The host PC 50 then constructs a user interface for creating a print job based on the printable information notified in step S604. Specifically, based on the printable information of the recording device 40, appropriate options such as print size and printable paper size are displayed on the display and provided to the user. Next, in step S605, the host PC 50 issues a print job.

In response, the recording device 40 receives the print job in step S614 and executes the print job in step S616. When printing based on the print job is completed in the recording device 40, the recording device 40 notifies the host PC 50 of the completion of printing in step S617. The host PC 50 receives the print completion notification in step S606 and notifies the user accordingly.

When the print job is completed, the host PC 50 and the recording device 40 each complete a series of print service processes.

In the above explanation, various types of information transmission are explained using an example in which the host PC 50 makes a request to the recording device 40, and the recording device 40 responds to the request. However, communication between the host PC and the recording device is not limited to the so-called pull type, and may be the so-called push type in which the recording device 40 spontaneously transmits information to the host PC 50 (and other host PCs) present on the network.

Figure 7 shows an example of a heating pulse applied to the recording head of a recording device. In Figure 7, timing p0 is the earliest in time, and it gets later in time as you move from the left to the right on the time axis.

On the left side of Figure 7, each color to be developed is written, and on the right side, the corresponding heating pulse is written. For example, when developing yellow (Y), in order to realize the heating temperature and heating time of area 21 in Figure 5, heating for a time of Δt1 is performed a total of two times with an interval of Δt0. Also, when developing magenta (M), in order to realize the heating temperature and heating time of area 22 in Figure 5, heating for a time of Δt2 is performed a total of three times with an interval of Δt0. Similarly, when developing cyan (C), in order to realize the heating temperature and heating time of area 23 in Figure 5, heating for a time of Δt3 is performed a total of four times with an interval of Δt0 each.

In addition, in FIG. 7, for ease of understanding, the relationship Δt1×2=Δt2×3=Δt3×4 is assumed to hold, and the total time of the heating pulse applied to the recording head 30 is the same regardless of which color is being produced.

However, the heating time is
t2 > Δt1+Δt0 > t1,
t3 > Δt2+Δt0×2 > t2,
Δt3+Δt0×3 > t3,
The relative relationship of the heating time for each image forming layer is as follows:
The heating time of Y is smaller than the heating time of M and smaller than the heating time of C. Here, Y, M, and C refer to the image forming layers 14, 16, and 18.

Here, the amount of heat applied by the recording head 30 is thermally conducted to the glaze 32, substrate 31, and heat sink 35 of the recording head 30 during the pulse interval Δt0, so that the temperature of the infrared imaging member 10 drops. Similarly, the amount of heat conducted to the infrared imaging member 10 is also thermally transferred to the platen 43, etc., so that the temperature of the infrared imaging member 10 drops accordingly. As a result, since the input energy is the same, the relative relationship of the peak temperatures of the image forming layers due to heating is as follows:
The peak temperature of Y>the peak temperature of M>the peak temperature of C.

Where:
Peak temperature of Y>Ta3
Ta3>M peak temperature>Ta2
Ta2>C peak temperature>Ta1
By controlling in this way, it is possible to develop each of the colors Y, M, and C (primary colors) independently.

Next, we will explain the heating pulses that control the color development of the secondary colors R, G, and B, and the tertiary color K. Here, a secondary color is a color that is reproduced using any two of the primary colors (i.e., Y, M, and C), and a tertiary color is a color that is reproduced using all of the primary colors.

In FIG. 7, the heating pulse is controlled so that red (R) develops in the order of yellow (Y) → magenta (M). In FIG. 7, the heating pulse is controlled so that green (G) develops in the order of yellow (Y) → cyan (C). Similarly, in FIG. 7, the heating pulse is controlled so that blue (B) develops in the order of magenta (M) → cyan (C). Finally, in FIG. 7, the heating pulse is controlled so that black (K) develops in the order of yellow (Y) → magenta (M) → cyan (C).

In this comparative example, when each of the single colors yellow (Y), magenta (M), and cyan (C) is developed, only the last heating pulse contributes to the development of the color, and the previous pulses play a role of preheating. In Fig. 7, among the pulses, the pulses mainly used for preheating (preheating pulses) are shaded, and the pulses mainly used for color development (image forming pulses: main pulses) are white. The timing of application of each heating pulse is as follows for each color. That is,
Color Preheat Pulse Image Formation Pulse
Application timing Application timing Y p0 p1
M p2, p3 p4
C p5, p6, p7 p8
R p0 p1, p2, p3, p4
G p0 p1, p5, p6, p7, p8
B p2, p3 p4, p5, p6, p7, p8
K p0 p1, p2, p3, p4, p5, p6, p7, p8
It is.

In this way, the drive pulses that can be used for actual image formation are each short. In particular, the pulse used for image formation of M, one of the monochrome colors M, C, and B, is extremely short. This is because when other colors are produced, the heating for the initial Y production has a preheating effect on the other colors.

Therefore, according to the comparative example described above, for colors that do not include yellow (Y), i.e., magenta (M) among magenta (M), cyan (C), and blue (B), most of the driving pulses used to develop each color are used for preheating, resulting in a short color development time. As a result, the color development area on the infrared imaging member 10 is narrow, resulting in an image with low color development.

For this reason, in Example 1, the following recording control process is performed for the comparative example described above.

・Explanation of the embodiment (FIGS. 8 to 12)
Fig. 8 is a flow chart showing the processing of the recording device 40 and the host PC 50 when executing the print service according to the embodiment 1 in the above-mentioned recording system. Note that in Fig. 8, the same processing steps as those already explained using Fig. 6 are given the same step reference numbers, and their explanation will be omitted.

In step S611 in FIG. 8, the recording device 40 confirms that it is capable of printing and also supports high color printing, and starts the print service. Also, in response to the print service Discovery in the host PC 50 in step S601, the recording device 40 notifies in step S612 that it is a device capable of providing print services including the high color printing service. Therefore, in step S613, the recording device 40 also notifies print capability information including information on the high color printing service.

In response to this, the host PC 50 notifies the user by displaying information on a display screen, such as the display of "Printing Service" and "High Color Printing Service" and the options to select whether to use the normal printing service or the high color printing service. In other words, in step S603, the process checks whether the instruction from the user is "Printing Service" or "High Color Printing Service."

If the user's selection is "Print Service", the process proceeds to step S605, where the same process as described in FIG. 6 is executed. However, if the selection is "High Color Print Service", the process proceeds to step S603A. Then, in step S603A, the host PC 50 constructs a user interface for creating a high color print job based on the printable information. Specifically, based on the printable information from the recording device 40, the print size, printable paper size, etc. are displayed on the screen. Furthermore, the user is prompted to select a selection in response to the display. In addition, a high color print job is created by displaying a highly colored preview image and allowing the user to select a high color method. Details of high color print job creation will be described later with reference to FIGS. 10 and 11. After the high color print job is created, the process proceeds to step S605.

Meanwhile, the recording device 40 checks in step S615 whether the received print job is a normal print job or a high color print job. If the received print job is a high color print job, the process proceeds to step S615A, where the high color print job is executed in high color print mode, and then proceeds to step S617. On the other hand, if the received print job is a normal print job, the same process as described in FIG. 6 is executed.

Figure 9 is a diagram showing an example of a heating pulse applied to the recording head of a recording device according to the process of Example 1. Note that in Figure 9, explanations of the same configurations and symbols as those explained in Figure 7 are omitted, and only the configuration unique to Example 1 is explained here.

As shown in Fig. 9, the pulse width of the first pulse of the driving pulse group for each color is lengthened to form a preheat pulse. In Fig. 9, the preheat pulses for high color development are indicated by thick diagonal lines and are the following three pulses. That is,
A pulse having a pulse width Δt4 applied at timing p2 for M color development;
A pulse having a pulse width Δt4 applied at timing p5 for coloring C;
A pulse having a pulse width Δt4 applied at timing p2 for B color development;
Here, the preheating time Δt4 is
Δt4 < heating time of Y Δt1 + Δt0, and Δt4 ≈ Δt1
The relative relationship of the heating time is as follows:
The heating time of Y<the heating time of M<the heating time of C remains the same as in the comparative example shown in FIG.

In this way, the pulse width Δt4 of the preheat pulse for high color development is
The heating pulse for preheating M color does not develop Y and C colors,
The heating pulse for preheating for C color development is set so that Y and M are not developed.

Here, the amount of heat applied by the recording head 30 is thermally conducted to the glaze 32, substrate 31, and heat sink 35 of the recording head 30 during the interval time Δt0, so the temperature of the infrared imaging member 10 drops. Similarly, the amount of heat conducted to the infrared imaging member 10 is also transmitted to the platen 43, etc., so the temperature of the infrared imaging member 10 drops accordingly. As a result, the input energy for coloring M and C increases by Δt4-Δt2 and Δt4-Δt3, respectively, but the peak temperatures due to heating are
The relationship remains Y peak temperature>M peak temperature>C peak temperature, which is the same as the comparative example shown in FIG.

In this respect, the pulse width Δt4 of the preheat pulse for high color development is
The heating pulse for preheating M color does not develop Y and C colors,
The heating pulse for preheating for C color development is set so that Y and M are not developed.

However, due to the presence of a preheating pulse,
The coloring time of M when M is monochromatic is close to that of R and K.
The color development time of C when the C single color is developed is close to that of G, B, and K.
The color development time of M in B becomes closer to the color development times of R and K. By controlling in this way, the color development time becomes longer, the color development area on the infrared imaging member 10 becomes wider, and a highly colored image is formed. More specifically, the application timing of the preheat pulse and image formation pulse that constitute the heating pulse for each color is detailed as follows. That is,
Color Preheat Pulse Image Formation Pulse
Application timing Application timing Y p0 p1
M p2 p3, p4
C p5 p6, p7, p8
R p0 p1, p2, p3, p4
G p0 p1, p5, p6, p7, p8
B p2 p3, p4, p5, p6, p7, p8
K p0 p1, p2, p3, p4, p5, p6, p7, p8
As described above, the pulses that can be used for actual image formation are each longer.

Figure 10 is a flowchart showing image processing for generating heating pulses to drive the recording head according to the first embodiment. This figure is a flowchart showing the details of the execution of the high color print job in step S615A of Figure 8.

As shown in FIG. 10, in step S1001, the image data in the high color print job received in step S814 is input. Next, in step S1002, if the image data has been compressed or encoded, a decoding process is performed, and further, in step S1003, a color correction process is performed. This can be performed on the host PC 50 side, but it is preferable to perform it on the recording device 40 when performing color correction according to the characteristics of the recording device 40. Even at this point, the image data is in the general RGB data format. However, at this point, it is generally RGB data that reflects the characteristics of the recording device 40, so-called device RGB.

Next, in step S1004, luminance/density conversion is performed. In a typical thermal printer, when each pixel and each color component is expressed in 8 bits,
C = 255 - R
M = 255 - G
Y = 255 - B
Here, the following conversion is performed:
In the case of preheat pulse control in this embodiment, for example, the preheat parameters when developing a single color of magenta (M) are different from the preheat parameters when developing a single color of red (R). Therefore, in order to set the two separately, it is desirable to perform luminance density conversion using a three-dimensional lookup table (3D_LUT). That is,
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
PM= 3D_LUT[R][G][B][3]
PC= 3D_LUT[R][G][B][4]
Here, PM and PC indicate density values corresponding to preheat pulses when developing M color and C color, respectively.

The above 3D_LUT is composed of 83,886,080 data tables (256 x 256 x 256 x 5). Each piece of data is the pulse width data to be applied at each timing p0 to p8 in FIG. 7. However, to reduce the amount of data, the number of grids may be reduced from 256 to 17, and 24,565 data tables (17 x 17 x 17 x 5) may be used to calculate the results using interpolation calculations in addition. Naturally, other than 17 grids, any suitable number of grids may be set, such as 16 grids, 9 grids, or 8 grids. Any interpolation method may be used, such as known tetrahedral interpolation.

Therefore,
Control pulses and preheat parameters that configure yellow (Y);
Control pulses and preheat parameters that configure magenta (M),
Control parameters and preheat parameters for cyan (C);
Magenta and yellow control parameters and preheat parameters that compose red (R);
Yellow and cyan control parameters and preheat parameters that make up green (G);
Magenta and cyan control parameters and preheat parameters that make up blue (B);
The control parameters for yellow, magenta, and cyan constituting black (K) and the preheat parameters can be set independently.

Furthermore, in step S1005, output correction is performed. First, the pulse widths (c, m, y, pm, pc) for realizing the color development of each density component C, M, Y and the preheating (pm, pc) for the color development of magenta and cyan are calculated using a one-dimensional lookup table (1D_LUT). That is,
c = 1D_LUT[C]
m = 1D_LUT[M]
y = 1D_LUT[Y]
pm= 1D_LUT[PM]
pc= 1D_LUT[PC]
Here, the maximum value of c is Δt3, the maximum value of m is Δt2, the maximum value of y is Δt1, and the maximum values of pm and pc are Δt4. The recording device 40 can modulate the color intensity of the infrared imaging member 10 by pulse width modulation (PWM), so that when the above-mentioned c, m, y, pm, and pc are smaller than the maximum values, the pulse width can be appropriately shortened to achieve the desired gradation. This process may be performed by using a known means.

To realize the pulse control process shown in FIG. 9, for example, in the case of M single color (R=255, G=0, B=255),
C = 3D_LUT[255][0][255][0] = 0
M = 3D_LUT[255][0][255][1] = Δt2
Y = 3D_LUT[255][0][255][2] = 0
PM= 3D_LUT[255][0][255][3] = Δt4
PC= 3D_LUT[255][0][255][4] = 0
It must be set as follows.

Similarly, for C monochrome (R=0, G=255, B=255),
C = 3D_LUT[0][255][255][0] = Δt3
M = 3D_LUT[0][255][255][1] = 0
Y = 3D_LUT[0][255][255][2] = 0
PM= 3D_LUT[0][255][255][3] = Δt4
PC= 3D_LUT[0][255][255][4] = 0
It must be set as follows.

Furthermore, here, the heating pulse from the recording head 30 is modulated according to the temperature of the infrared imaging member 10 acquired by a temperature sensor (not shown) or the like. Specifically, the pulse width required to reach the activation temperature is controlled to be shorter as the acquired temperature increases. This process may be performed using known means. Also, the temperature of the infrared imaging member 10 may not only be directly detected by a temperature sensor (not shown) or the like, but the CPU 501 may estimate the temperature of the infrared imaging member 10 and control based on the estimated temperature. Any known method may be used as the method of temperature estimation.

Furthermore, in step S1006, a preheat pulse for high color development is generated and synthesized. Here, the preheat pulse intensity for high color development is pre.

Next, the pulse widths for forming an image and the preheat pulses are synthesized. That is, the pulses are synthesized with the pulse widths at timings p0 to p8 set as p0=y, p1=y, p2=max(m,pm), p3=m, p4=m, p5=max(c,pc), p6=c, p7=c, and p8=c. Here, max(x,y) is a function that sets the larger value of x and y. When realizing this by superimposing the pulses generated by the electric circuits,
p2 = m or pm
p5=c or pc, where x or y represents the logical sum of the signal x and the signal y.

Next, in step S1007, head control is performed. That is, the pulse width at the above timings p0 to p8 is controlled to form the desired color development and high color development processing on the infrared image member 10.

Next, in step S1008, it is checked whether recording of the page is complete. If the result is No, the process returns to step S1003 to record the rest of the page. If the result is Yes, the printing process ends.

Therefore, by following the embodiment described above, it is possible to achieve high color recording at each pixel on the infrared imaging member.

<Modification 1>
Fig. 11 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 1 of Example 1. Note that in Fig. 11, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 1 of Example 1 are explained here.

Here, the preheat pulse, indicated by the dark diagonal lines, is constantly applied at timing p0. By controlling it in this way, the heating pulse for color development and the preheat pulse can be treated as separate pulses, simplifying the control of the circuit.

Also, as can be easily understood from FIG. 11, the shapes of the pulses that produce each color are very similar to each other.
The difference in the color development degree of C color among C color, G color, and B color,
The difference in the color development degree of M color between M color and each of R color and B color,
can be made smaller, allowing for smooth color gradations to be expressed.

Furthermore, since the preheat pulse is applied at only one point (timing p0), it is sufficient to set one type of preheat pulse, which has the effect of reducing the amount of preheat control parameters by half.

As a specific processing method, luminance/density conversion using a three-dimensional lookup table is performed as follows.
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
P = 3D_LUT[R][G][B][3]
Here, P represents the density value corresponding to the preheat pulse.

Next, the pulse width for achieving each of the C, M, and Y densities and preheating intensities is calculated. That is,
c = 1D_LUT[C]
m = 1D_LUT[M]
y = 1D_LUT[Y]
p = 1D_LUT[P]
The pulse widths at the timings p0 to p8 are calculated as follows:
The pulses are synthesized as p0=max(y,p), p1=y, p2=m, p3=m, p4=m, p5=c, p6=c, p7=c, and p8=c.

In addition, when the pulses generated by the electric circuits are superimposed, the pulse width at the timing p0 is set as p0=max(m, p).
Here, x or y represents the logical sum of the signal x and the signal y.

By controlling the pulse width at each timing as described above, the heating position by the preheat pulse can be fixed, and a high color reproduction mode that can express smooth color gradations with a simpler system can be realized.

<Modification 2>
Fig. 12 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 2 of Example 1. Note that in Fig. 12, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 2 of Example 1 are explained here.

Here, we explain an example in which a preheat pulse is achieved by using a color-emitting pulse of another color, without setting a dedicated preheat pulse.

Among the pulses shown in FIG. 12, the heating pulse group for preheating for high color development (thickly shaded) is the following three pulse group.
A pulse having a heating time Δt5 applied at timings p0 and p1 for M color development;
A pulse having a heating time Δt6 is applied at timings p2, p3, and p4 for coloring C;
A pulse having a heating time Δt5 applied at timings p0 and p1 for B color development;
It is.

Here, the preheating times Δt5 and Δt6 are respectively
Δt5 < heating time of Y Δt1/2,
Δt6 < M heating time Δt2/2
The reason why the preheating times Δt5 and Δt6 are set to pulse widths equal to or less than half the Y heating time Δt1 and the M heating time Δt2 is as follows: That is, the preheating pulse is set to a pulse width that does not cause color development alone, and does not cause other colors to develop even when used in combination with a color development pulse, and the pulse width can be set arbitrarily within that range.

Here, the preheating pulse is performed using a weak heating pulse for other colors that does not result in color development, making control even simpler.

As a specific processing method, in order to realize the heating pulse for preheating shown in FIG. 12, the luminance density conversion using a three-dimensional lookup table is performed as follows. That is,
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
Calculate the following.

To realize the process shown in FIG. 12, for example, in the case of M single color (R=255, G=0, B=255),
C = 3D_LUT[255][0][255][0] = 0
M = 3D_LUT[255][0][255][1] = Δt2
Y = 3D_LUT[255][0][255][2] = Δt1/2
It must be set as follows.

Similarly, for C monochrome (R=0, G=255, B=255),
C = 3D_LUT[0][255][255][0] = Δt3
M = 3D_LUT[0][255][255][1] = Δt2/2
Y = 3D_LUT[0][255][255][2] = 0
It must be set as follows.

By setting it up in this way, subsequent processing is carried out in the same way as in the comparative example, and a high color recording mode can be achieved with a simple configuration without having to set a dedicated preheating heating pulse separately from the color-developing pulse.

Note that while the above explanation is for monochrome M, monochrome C, and monochrome B, the preheat control according to the present invention can also be applied to intermediate colors. For example, by setting appropriate preheat pulses for a white to M gradation, white to C gradation, or white to B gradation, it is possible to achieve high color reproduction.

<Modification 3>
Fig. 13 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 3 of Example 1. Note that in Fig. 13, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 3 of Example 1 will be explained here.

This example is a configuration that simultaneously realizes both the advantage of being able to smoothly express the color gradation described in Variation 1 of Example 1, and the advantage of being able to configure a dedicated preheating heating pulse without having to set it separately from the color-developing pulse described in Variation 2 of Example 1.

Among the pulses shown in FIG. 13, the heating pulse group for preheating for medium and high color development is the following three pulse group.
A pulse of heating time Δt5 applied at timings p0 and p1 for M color development;
A pulse having a heating time Δt5 applied at timings p0 and p1 for coloring C;
A pulse having a heating time Δt5 applied at timings p0 and p1 for B color development;
Here, the heating time Δt5 for preheating is expressed as follows, as explained with reference to FIG.
Δt5 < heating time of Y Δt1/2
It is as follows.

As a specific processing method, in order to realize the heating pulse for preheating shown in FIG. 13, the luminance density conversion using a three-dimensional lookup table is performed as follows. That is,
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
Calculate the following.

To realize the process shown in FIG. 13 , for example, in the case of M single color (R=255, G=0, B=255),
C = 3D_LUT[255][0][255][0] = 0
M = 3D_LUT[255][0][255][1] = Δt2
Y = 3D_LUT[255][0][255][2] = Δt1/2
It must be set as follows.

Similarly, for C monochrome (R=0, G=255, B=255),
C = 3D_LUT[0][255][255][0] = Δt3
M = 3D_LUT[0][255][255][1] = 0
Y = 3D_LUT[0][255][255][2] = Δt1/2
It must be set as follows.

By setting it up in this way, subsequent processing is carried out in the same way as in the comparative example, and a high color recording mode can be achieved with a simple configuration without having to set a dedicated preheating heating pulse separately from the color-developing pulse.

In the first embodiment, we described an example in which the preheat pulse contributes to extending the color development time, thereby achieving high color development. In this embodiment, we describe an example in which extending the color development time is used to improve printing speed.

Figure 14 is a flow chart showing the processing of the recording device 40 and the host PC 50 when the high-speed print service according to the second embodiment is executed in the above-mentioned recording system. Note that in Figure 14, the same processing steps as those already explained using Figure 6 are given the same step reference numbers, and their explanations are omitted.

In step S611 in FIG. 14, the recording device 40 confirms that it is capable of printing and also supports high-speed printing, and starts the print service. Also, in response to the print service Discovery in the host PC 50 in step S601, the recording device 40 notifies in step S612 that it is a device capable of providing print services including high-speed print services. Therefore, in step S613, the recording device 40 also notifies print capability information including information on the high-speed print service.

In response to this, the host PC 50 notifies the user by displaying information for selecting whether to use the normal printing service or the high-speed printing service, specifically, the display of "printing service" and "high-speed printing service" and the options on a display or the like. That is, in step S603', the process checks whether the instruction from the user is "printing service" or "high-speed printing service."

If the user's selection is "Print Service", processing proceeds to step S604, where the same processing as described in FIG. 6 is executed, but if the selection is "High Speed Print Service", processing proceeds to step S603". Then, in step S603", the host PC 50 constructs a user interface for creating a high speed print job based on the printable information. Specifically, based on the printable information from the recording device 40, the print size, printable paper size, etc. are displayed on the screen, and the user is prompted to select an appropriate option. In addition, the high speed print job is created while the user is made aware of high speed printing by, for example, displaying a preview image in high speed animation. After the high speed print job is created, processing proceeds to step S605.

Meanwhile, the recording device 40 checks in step S615' whether the received print job is a normal print job or a high-speed print job. If the received print job is a high-speed print job, the process proceeds to step S615'', where the high-speed print job is executed in high-speed print mode, and then proceeds to step S617. On the other hand, if the received print job is a normal print job, the same process as described in FIG. 6 is executed.

Figure 15 is a diagram showing an example of a heating pulse applied to the recording head of a recording device according to the process of Example 2. Note that in Figure 15, explanations of the same configurations and symbols as those explained in Figures 7 and 9 are omitted, and only the configuration unique to Example 2 is explained here.

In this embodiment, the effect of increasing the number of pulses that contribute to color development due to the preheating heating pulses is used to improve printing speed while maintaining density with the control configuration shown in the comparative example.

As shown in Figure 15, when yellow (Y) is to be developed, in order to realize control that satisfies region 21 shown in Figure 5 (where the temperature of the print head is relatively high and the heating time is relatively short), a heating pulse is applied twice for heating time Δt1 in a time interval Δt0. Also, when magenta (M) is to be developed, a heating pulse is applied twice for heating time Δt2 in a time interval Δt0. Similarly, when cyan (C) is to be developed, a heating pulse is applied three times for heating time Δt3 in a time interval Δt0.

Now, comparing Figure 15 with Figure 7, the number of M heating pulses and C heating pulses is one less in the conventional case, so the heating pulse is too short for single color M, single color C, and M in B, resulting in weak color development. On the other hand, the decrease in color development for the other colors is small for the following reasons. That is,
The heating for the R color acts as a preheat for the Y color.
For G, the heating for Y color development acts as a preheat for C color development.
For K color, the heating for Y color development plays a role of preheating for M and C color development.

Therefore, as shown in FIG. 15, a preheating pulse with a longer pulse width (a pulse with dark diagonal lines in the figure) is applied once only immediately before the start of the heating pulse for M single color, C single color, and M in B.

In this way, by using a preheating pulse with a longer pulse width, while the comparative example and Example 1 required a total of nine timings p0 to p8 to form an image of one pixel, this can be achieved in this Example with a total of seven timings p0 to p6. As a result, recording can be performed at a speed approximately 20% faster.

Incidentally, the image processing for generating heating pulses and driving the recording head according to the second embodiment is almost the same as the processing explained with reference to FIG. 10 in the first embodiment, so the explanation of the same processing will be omitted.

In this embodiment, the processes up to brightness density conversion and output correction are executed in the same manner as the pulse control described with reference to FIG. 10 in the first embodiment. In the subsequent preheat pulse generation and synthesis in step S1006, the pulses are synthesized with the pulse widths at timings p0 to p6 as p0=y, p1=max(y, pm), p2=m, p3=max(m, pc), p4=c, p5=c, and p6=c.

If you want to achieve this by superimposing the pulses generated by the electrical circuits, you can set p1 = y or pm and p3 = m or pc.

According to the embodiment described above, the printing speed can be improved by using a preheating pulse with a longer color development time.

<Modification 1>
Fig. 16 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 1 of Example 2. Note that in Fig. 16, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 1 of Example 2 are explained here.

This modified example is an example that simultaneously achieves the improvement in printing speed by utilizing the longer color development time described in Example 2, the improvement in smoothness of gradation described in Modification 1 of Example 1, and the simplification of the control configuration.

In this modified example, as shown in FIG. 16, as explained in modified example 1 of embodiment 1, a preheating pulse is applied at timing p0. Also, as in embodiment 2, when developing magenta (M), a drive pulse with a heating time of Δt2 is applied a total of two times at a time interval of Δt0. Furthermore, when developing cyan (C), a drive pulse with a heating time of Δt3 is applied a total of three times at a time interval of Δt0, as in embodiment 2.

Note that the image processing according to this modified example is the same as the processing described with reference to the flowchart in FIG. 10, so its description will be omitted.

In this modified example, the processes up to the luminance density conversion and output correction are executed in the same manner as the pulse control described with reference to FIG. 10 in the first embodiment. In the subsequent preheat pulse generation and synthesis in step S1006, the pulses are synthesized with the pulse widths at timings p0 to p6 as p0=max(y,p), p1=y, p2=m, p3=m, p4=c, p5=c, and p6=c.

If you want to achieve this by superimposing the pulses generated by the electrical circuits, you can make p0 = y or p.

By controlling in this way, the preheating pulse is used at the beginning of the Y color generation, which increases the color generation time and improves printing speed, while at the same time improving the smoothness of the gradation and simplifying the configuration.

<Modification 2>
Fig. 17 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 2 of Example 2. Note that in Fig. 17, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 2 of Example 2 are explained here.

This modified example is an example that simultaneously achieves both improved printing speed by using longer color development time as described in Example 2, and simplified control by using a color development pulse of a different color as the preheating heating pulse as described in Modified Example 2 of Example 1.

In this modification, as explained in modification 2 of embodiment 1, a preheating pulse is applied using a color-developing pulse of another color.

Specifically, in order to realize the preheating heating pulse shown in FIG.
The luminance-density conversion using a three-dimensional lookup table is performed as follows:
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
To realize the process shown in FIG. 17, for example, in the case of M single color (R=255, G=0, B=255), the following is calculated:
C = 3D_LUT[255][0][255][0] = 0
M = 3D_LUT[255][0][255][1] = Δt2
Y = 3D_LUT[255][0][255][2] = Δt1/2
It must be set as follows.

Similarly, for C monochrome (R=0, G=255, B=255),
C = 3D_LUT[0][255][255][0] = Δt3
M = 3D_LUT[0][255][255][1] = Δt2/2
Y = 3D_LUT[0][255][255][2] = 0
It must be set as follows.

By setting it in this way, the subsequent processing is executed in the same way as in the comparative example, so that the high-speed recording mode can be realized with a simple control configuration without separately setting a dedicated preheating heating pulse and a coloring pulse. Also, in this example, as in the second modification of the first embodiment, high-speed recording can be realized by setting an appropriate preheating heating pulse for a white to M color gradation, a white to C color gradation, or a white to B color gradation.

<Modification 3>
Fig. 18 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 3 of Example 2. Note that in Fig. 18, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 3 of Example 2 are explained here.

This modified example is an example that simultaneously achieves both the advantage of being able to smoothly express color gradations, as described in modified example 1 of embodiment 2, and the advantage of not having to separately set a dedicated heating pulse for preheating and a pulse for color development, as described in modified example 2 of embodiment 1.

Among the pulses shown in FIG. 18, the heating pulse group for preheating for medium and high color development is the following three pulse group.
A pulse having a heating time Δt5 applied at timings p0 and p1 for M color development;
A pulse having a heating time Δt5 applied at timings p0 and p1 for coloring C;
A pulse having a heating time Δt5 applied at timings p0 and p1 for B color development;
Here, the heating time Δt5 for preheating is Δt5<Y, ie, Δt1/2, as in the case shown in FIG.

Specifically, in order to realize the heating pulse for preheating shown in FIG. 18, the luminance/density conversion using the three-dimensional lookup table is performed as follows:
C = 3D_LUT[R][G][B][0]
M = 3D_LUT[R][G][B][1]
Y = 3D_LUT[R][G][B][2]
To realize the process shown in FIG. 18, for example, in the case of M single color (R=255, G=0, B=255), the following is calculated:
C = 3D_LUT[255][0][255][0] = 0
M = 3D_LUT[255][0][255][1] = Δt2
Y = 3D_LUT[255][0][255][2] = Δt1/2
It must be set as follows.

Similarly, for C monochrome (R=0, G=255, B=255),
C = 3D_LUT[0][255][255][0] = Δt3
M = 3D_LUT[0][255][255][1] = 0
Y = 3D_LUT[0][255][255][2] = Δt1/2
It must be set as follows.

By setting it up in this way, the subsequent processing is executed in the same way as in the comparative example, and the high-speed recording mode can be realized with a simple configuration without having to set up separate heating pulses for dedicated preheating and pulses for color development.

10 are executed individually, but they do not necessarily have to be executed individually, and they may be executed together in one step as follows. That is, the pulse widths at the timings p0 to p6 may be calculated as follows using a three-dimensional lookup table. That is,
p0 = 3D_LUT[R][G][B][0]
p1 = 3D_LUT[R][G][B][1]
p2 = 3D_LUT[R][G][B][2]
p3 = 3D_LUT[R][G][B][3]
p4 = 3D_LUT[R][G][B][4]
p5 = 3D_LUT[R][G][B][5]
p6 = 3D_LUT[R][G][B][6]
Calculate the following.

The above setting of timings p0 to p6 is for the case where the processing of the second embodiment is consolidated into one step. In the case of the processing of the first embodiment, p7 = 3D_LUT[R][G][B][7]
p8 = 3D_LUT[R][G][B][8]
Just add:

By performing such calculations, the pulse width for each timing at which the heater of the recording head 30 is driven is uniquely determined, which has the advantage that it can be realized with a very simple configuration.

In addition, the above configuration makes it possible to control any pulse according to the combination of the three colors YMC, which has the advantage of greatly increasing the degree of freedom in control.

In Example 1, an example is described in which the preheat pulse contributes to a longer color development time to achieve high color development, and in Example 2, an example is described in which the longer color development time is used to improve printing speed. Both of these examples are examples in which a preheat pulse is determined by performing brightness density conversion using a 3D_LUT for each color component of the recording device (thermal printer) from each pixel value of the image data. In this example, an example is described in which, in order to achieve improved color development at the start of an image in the transport direction of the recording medium (infrared image member) 10 in Figure 1, a preheat pulse for the pixel immediately preceding it is determined from the value of each pixel in the transport direction.

As explained in the first embodiment, heating to produce a certain color has a preheating effect on the other colors that will be produced after the first color. In other words, heating performed in advance in each pixel has a preheating effect for the subsequent heating. This preheating effect caused by prior heating occurs not only within a pixel, but also between pixels.

Figure 19 shows the relationship between the image I formed on the infrared image member 10 and the transport direction D of the infrared image member 10.

In FIG. 19, the shaded portion is image I, and the pixel region in image I where the most downstream pixels are arranged in a direction intersecting with the transport direction D is shown as image start IA, and the other regions are shown as internal region IB. Also, the region in which the pixels without color-producing data just before image I are arranged in a direction intersecting with the transport direction D is shown as previous pixel region IW. That is, the pixels included in image start IA are located on the upstream side with respect to transport direction D, and the pixels included in previous pixel region IW are located on the downstream side. The image start IA and internal region IB are included in the image forming region, and the previous pixel region IW is a non-image forming region. In FIG. 19, for example, when image I is recorded using the heating pulse shown in FIG. 7 in the comparative example, the preheating effect of the previous pixel region IW on the image start IA is smaller than the preheating effect between pixels in the internal region IB of the image. This is because there is no heating pulse for the white pixels that continue up to the pixel area IW immediately preceding the image start IA, so the pixels at the image start IA receive little preheating from the pixel area IW immediately preceding it.

7, in the case of C monochrome color development, p5 to p7 are explained as preheat pulses and p8 is an image formation pulse, but the number of preheat pulses required at the image start IA tends to be greater than in the inner region IB , and the number of image formation pulses tends to be fewer. In other words, compared to the color development in the inner region IB, the color development region at the image start IA is narrower in the transport direction, resulting in an image with lower color development.

Figure 20 is a diagram showing an example of a heating pulse applied to the recording head 30 of the recording device 40 according to the third embodiment. Note that in Figure 20, explanations of the same configurations and symbols as those explained in Figure 7 are omitted, and only the configurations unique to the third embodiment are explained here.

In FIG. 20, p'0 to p'8 indicate the heating timing in the pixel region IW immediately preceding the image start IA, and p0 to p8 indicate the heating timing of the image start IA. The heating pulse of the image start IA in FIG. 20 is based on the heating pulse in FIG. 7, and the same is true for FIG. 21 and FIG. 22 described later. In FIG. 20, the diagonal lines indicate preheat pulses. The heat from the preheat pulse applied to the immediately preceding pixel region IW not only preheats the immediately preceding pixel region IW, but also exerts a preheating effect on the image start IA. The heat amount from the pulse applied by the recording head 30 propagates not only in the depth direction of the infrared imaging member 10, but also partially in the transport direction to heat the infrared imaging member 10, so the preheat pulse of the immediately preceding pixel region IW also has a preheating effect on the image start IA. Therefore, the difference in the preheating effect between the image start IA and the internal region IB in FIG. 20 can be reduced. Specifically, the application timing of the preheat pulse and the image forming pulse constituting the heating pulse of each color is detailed as follows. That is,
Color of the previous pixel area IW of the image start end IA of the image start end IA
Preheating pulse Preheating pulse Imaging pulse
Application timing Application timing Application timing Y p'8 p0 p1
M p'7, p'8 p2, p3 p4
C p'6, p'7, p'8 p5, p6, p7 p8
R p'8 p0 p1~p4
G p'6, p'7, p'8 p0 p1, p5~p8
B p'7, p'8 p2, p3 p4~p8
K p'8 p0 p1~p6
The heating pulse applied to the immediately preceding pixel region IW is a preheat pulse, unlike that applied to the image start end IA, so the immediately preceding pixel region IW does not develop color. In addition, in FIG. 20, the preheat pulse of the immediately preceding pixel region IW reflects the characteristics of each color.

First, we will explain one feature of preheating the immediately preceding pixel area IW when the image start end IA is a single color of Y, M, or C.

The relationship between the preheat pulse widths of Y, M, and C in the previous pixel P is Y>M>C (Δt'1>Δt'2>Δt'3). Here, we will use the preheat pulse widths to explain, but it can also be explained in terms of the so-called duty ratio or duty cycle. The duty ratio or duty cycle is the proportion of the period during which the pulse (signal) is not zero in a certain period. In the example of FIG. 20, for the preheat pulse in the previous pixel region IW of Y, the certain period is Δt0, and the period during which the signal is not zero in period Δt0 is Δt'1. Therefore, the duty ratio of the preheat pulse in the previous pixel region IW of Y is Δt'1/Δt0. Similarly, the preheat pulse duty ratio in the previous pixel region IW of M is Δt'2/Δt0, and the preheat pulse duty ratio in the previous pixel region IW of C is Δt'3/Δt0.

In Fig. 20, Δt'1, Δt'2, and Δt'3 are depicted as a single pulse with different widths, but the preheat pulse is not limited to this. For example, the pulse widths Δt'1 , Δt'2 , and Δt'3 may be divided into pulses of narrower widths. In this case, the ratio of the total period during which the divided signal is not zero at Δt0 becomes the duty ratio or duty cycle. The relationship between the duty ratios of the preheat pulses of Y, M, and C at the immediately preceding pixel P is Y>M>C (Δt'1/Δt0>Δt'2/Δt0>Δt'3/Δt0).

Next, we will explain another feature of preheating the previous pixel area IW when the image start end IA is a single color of Y, M, or C.

The number of times each preheat pulse is applied to the pixel area IW immediately preceding Y, M, and C is Y<M<C. In the example of FIG. 20, Y (1 time)<M (2 times)<C (3 times). If Δt0 is the pulse period, and since the period is time, the total application time can be calculated by multiplying the period by the number of times. The application time for each preheat pulse to the pixel area IW immediately preceding Y, M, and C is Y<M<C.

Y is formed in the image forming layer 14 in FIG. 4, and the activation temperature Ta3 is higher than the activation temperatures Ta2 and Ta1 of the image forming layers 16 and 18. Therefore, the preheat pulse width is widened to apply a high temperature to the infrared image member 10. At this time, the number of application timings is reduced so that the image forming layers 16 and 18 of M and C do not reach their respective activation temperatures Ta2 and Ta1. On the other hand, the activation temperature Ta1 of the image forming layer 18 that develops C is the lowest. Therefore, the preheat pulse width is narrowed to apply a low temperature to the infrared image member 10. At this time, the heat diffusion at a low temperature caused by the applied preheat pulse is suppressed by the spacer layers 15 and 17 in the middle, so by increasing the number of application timings, the low temperature heat is diffused to the image forming layer 18 of C. The image forming layer 16 that produces the color M is located between the image forming layer 14 of Y and the image forming layer 18 of C, so both the preheat pulse width and the number of application timings are between Y and C.

Furthermore, we will explain the characteristics of preheating the previous pixel area IW when the image start end IA is colored R or K.

In this case, the preheat pulse width is Δt'1, and the application timing is p'8. Since the Y image forming layer 14 is used to produce the colors R and K, the characteristics of the preheat pulse are the same as those for the single color Y.

Next, we will explain the characteristics of preheating the previous pixel area IW when the image start end IA is G color.

In this case, the preheat pulse width is Δt'3, and the application timings are p'6, p'7, and p'8. The Y image-forming layer 14 is also used for G color development, and although the preheat pulse for Y single-color development has a particularly effective preheating effect on the Y image-forming layer 14, it does not have a large preheating effect on the C image-forming layer 18. In the case of G color development, it is more preferable to give priority to the preheating effect on p5, p6, and p7, which develop C at the image start IA, and to use a preheat pulse similar to that for C single-color development. Since the Y image-forming layer 14 is located shallower than the C image-forming layer 18, the preheat temperature can be made higher than that of the image-forming layer 18 even if a preheat pulse giving priority to C color development is used.

Finally, we will explain the characteristics of preheating the previous pixel area IW when the image start end IA is colored B.

In this case, the preheat pulse width is Δt'2, and the application timings are p'7 and p'8. Because the M image forming layer 16 is used to develop the color B, the characteristics of the preheat pulse are the same as for the M single color development. This preheat pulse and the preheat pulses with application timings p2 and p3 at the start of the image IA create an application time that can preheat the C image forming layer 18.

In this way, it is preferable to give the preheat pulse for the immediately preceding pixel area IW the above characteristics in accordance with the color developed at the image beginning IA .

As described above, for R, B, and K, the same preheat pulse as that for the image forming layer with the highest activation temperature during monochrome color development is applied to the immediately preceding pixel region IW. This is because the image forming layer with the highest activation temperature is activated first at the image start end IA . However, the present invention is not limited to this. Even if a preheat pulse for monochrome color development of another image forming layer is used, there is at least a preheat effect on each layer.

FIG. 21 is a diagram for explaining the application timing of the preheat pulse to the immediately preceding pixel region IW, which is different from that in FIG. 20. That is,
Color Application timing of preheat pulse of image formation pulse of image start edge IA of previous pixel area IW Y p'8 p0 p1
M p'6, p'7 p2, p3 p4
C p'3, p'4, p'5 p5, p6, p7 p8
R p'8 p0 p1~p4
G p'3, p'4, p'5 p0 p1, p5 to p8
B p'6, p'7 p2, p3 p4~p8
K p'8 p0 p1~p6
It is.

In the example shown in FIG. 21, there are no overlapping preheat pulses in the application timings of Y, M, and C in the immediately preceding pixel region IW. Comparing the temperature changes over time of the Y image forming layer 14 and the M image forming layer 16, the image forming layer 16, which is located deeper, is smaller, so it takes longer for the temperature to drop after the temperature is raised by the preheat pulses at application timings p'6 and p'7. The C image forming layer 18 is located even deeper, so it takes even longer for the temperature to drop. Therefore, even if a timing is provided where no preheat pulses are applied after the application of the M and C preheat pulses in the immediately preceding pixel region IW as in FIG. 21, the preheat effect is still produced. However, because a temperature drop occurs at the timing where no preheat pulse is applied, the example shown in FIG. 20 has a greater preheat effect on the image start IA.

Figure 22 is a flowchart showing image processing for generating heating pulses to drive the recording head according to the third embodiment. This figure is a flowchart showing the details of the print job execution in step S616 in each of Figures 6, 8, and 14. Note that in Figure 22, the same processing steps as those already explained in Figure 10 are given the same step reference numbers and their explanation is omitted. Here, only the processing steps unique to this embodiment will be explained.

As shown in FIG. 22, first, in step S1000, the flag value (described later) is initialized to "0". After that, in step S1001, image data is input, and in step S1002, if the image data has been compressed or encoded, a decoding process is executed. In step S1002-1, it is checked whether the line being processed (line n) in the direction perpendicular to the transport direction D is in the non-coloring region and whether the next (n+1) line is in the coloring region. If the result here is Yes, processing proceeds to step S1002a, and if the result is No, processing proceeds to step S1002-2.

In step S1002a, pixels of line n and line (n+1) of the image data are input in the direction perpendicular to the transport direction D. In step S1002b, the same color correction process as in step S1003 is executed. In step S1002c, it is checked whether the pixels of line n are specific color data. In this example, it is checked whether the specific color is "white", that is, whether R=255, G=255, B=255. If the pixels are white, which is the specific color (Yes), the process proceeds to step S1002d, where the pixels of line n are processed as the previous pixel area IW. On the other hand, if the pixels are not of the specific color (No), the process proceeds to step S1004.

In step S1002d, the flag value is set to "1". Next, in step S1002e, a preheat luminance density conversion is executed using a three-dimensional lookup table for preheat (3D_LUTpre). In this process, pixel values of the (n+1)th line of image data are input to 3D_LUTpre, and density values corresponding to the preheat pulse of each pixel of n lines of white data are generated. That is,
PY = 3D_LUTpre[R][G][B][0]
PM = 3D_LUTpre[R][G][B][1]
PC = 3D_LUTpre[R][G][B][2]
Here, PY, PM, and PC respectively indicate density values corresponding to the preheat pulses of the previous pixel area IW of the nth line of Y, M, and C colors. The pixels of the nth line correspond to the previous pixel area IW in FIG. 19, and the pixels of the (n+1)th line correspond to the image start end IA .

Here, the above 3D_LUTpre is composed of 50,331,648 data tables of 256×256×256×3. Each data is density value data corresponding to the pulse width applied at each application timing p'0 to p'8 in FIG. 20 and FIG. 21. In order to reduce the data amount of the LUT, the number of grids may be reduced as in the 3D_LUT of the first embodiment. Whether the preheat pulse is applied at any of the application timings p'0 to p'8 of each color may be determined in advance at the application timings shown in FIG. 20 and FIG. 21. A preheat pulse width, which will be described later and corresponds to a density value determined by the 3D_LUTpre at a predetermined application timing may be applied. Furthermore, by setting a density value corresponding to the preheat pulse width at the application timings p'0 to p'8 in the 3D_LUTpre for each application timing, both the density value corresponding to the preheat pulse width and the application timing can be determined by the 3D_LUTpre. That is,
PY = 3D_LUTpre[R][G][B][0][1][2][3][4][5][6][7][8]
PM = 3D_LUTpre[R] [G] [B] [9] [10] [11] [12] [13] [14] [15] [16] [17]
PC = 3D_LUTpre[R] [G] [B] [18] [19] [20] [21] [22] [23] [24] [25] [26]
Calculate the following.

Here, [0] to [8], [9] to [17], and [18] to [26] correspond to the storage of preheat pulse width data for application timings p'0 to p'8, respectively.

Therefore, as shown in Figures 20 and 21, it is possible to set the preheat parameters for the previous pixel area IW independently for each color.

Next, in step S1002f, preheat output correction is performed. Specifically, a one-dimensional lookup table for preheat (1D_LUTpre) is used to calculate preheat pulse widths py, pm, and pc from the density values PY, PM, and PC corresponding to the preheat pulse widths. That is,
py = 1D_LUTpre[PY]
pm = 1D_LUTpre[PM]
pc = 1D_LUTpre[PC]
Then, in step S1002g, preheat pulse generation and synthesis are performed. Preheat pulses are set for application timings p'0 to p'8.

In FIG. 20, there are cases where multiple of the preheat pulse widths py, pm, and pc have the same application timing. However, for one application timing, it is necessary to decide on one of the preheat pulse widths. There are multiple ways to decide this.

For example, when priority is given to preventing color development in the immediately preceding pixel region IW, the minimum values of py, pm, and pc that are not 0 at each application timing are set at each application timing. That is,
p'0 = min(py0, pm0, pc0)
p'1 = min(py1, pm1, pc1)
p'2 = min(py2, pm2, pc2)
p'3 = min(py3, pm3, pc3)
p'4 = min(py4, pm4, pc4)
p'5 = min(py5, pm5, pc5)
p'6 = min(py6, pm6, pc6)
p'7 = min(py7, pm7, pc7)
p'8 = min(py8, pm8, pc8)
Here, the values (0 to 8) added after py, pm, and pc correspond to the application timings. Note that when all of the preheat pulse widths py, pm, and pc are 0, the preheat pulse width is set to 0.

On the other hand, if priority is given to increasing the preheating temperature, the maximum widths of py, pm, and pc at each application timing are set to each application timing.
p'0 = max(py0, pm0, pc0)
p'1 = max(py1, pm1, pc1)
p'2 = max(py2, pm2, pc2)
p'3 = max(py3, pm3, pc3)
p'4 = max(py4, pm4, pc4)
p'5 = max(py5, pm5, pc5)
p'6 = max(py6, pm6, pc6)
p'7 = max(py7, pm7, pc7)
p'8 = max(py8, pm8, pc8)
Also, the balance may be adjusted by averaging or weighted averaging py, pm, and pc at each application timing.

Furthermore, in step S1007, head control is executed. That is, by controlling the preheat pulse width to the set width at the application timings p'0 to p'8, a preheat pulse is applied to the immediately preceding pixel area IW, thereby exerting a preheat effect on the image leading edge IA .

Then, step S1008 is executed to determine whether to continue processing the page or end processing.

Now, in step S1002-1, if it is determined that the line (n) being processed is in the color gamut (No), the process proceeds to step S1002-2, where the pixels of the nth line are input. Thereafter, the above-mentioned steps S1003 and S1004 are executed. That is, the density values of the pixels at the application timings p0 to p8 shown in Figures 20 and 21 and Figure 23 described below are calculated.

In step S1004-1, it is checked whether the flag value is "1". If the flag value is "1" (Yes), the process proceeds to step S1004-2, where the flag value is set to "0". The pixels on the nth line are then processed as the image start point IA. The process proceeds to step S1005'. On the other hand, if the flag value is "0" (No), the process proceeds to step S1004-3, where the pixels on the nth line are processed as the internal area IB.

In step S1005', output correction for the image start edge is executed. Specifically, a one-dimensional lookup table for the image start edge (1D_LUTstart) is used to calculate preheat pulse widths py, pm, and pc from density values PY, PM, and PC corresponding to the preheat pulse widths. The calculated preheat pulse widths are the preheat widths at application timings p0 to p8, which are the image start edge IA in Figures 20 and 21 and Figure 23 described below. That is,
py = 1D_LUTstart[PY]
pm = 1D_LUTstart[PM]
pc = 1D_LUTstart[PC]
Calculate the following.

Now, as can be seen by comparing Figures 20 and 21 with Figure 7, the preheat pulse width of py at application timing p0, Δt"1, is narrower than Δt1 in Figure 7. The reason for this is that a preheat pulse of Δt'1 is applied at application timing p'8 of the immediately preceding pixel region IW, and this is to prevent excessive preheating.

Figure 23 is a diagram explaining the application timing of the preheat pulse to the immediately preceding pixel region IW, which is different from that of Figure 20. In Figure 23, the preheat pulse width Δt" is the same as Δt1 in Figure 7, and Δt'1 is narrower than in Figures 20 and 21. The control to narrow Δt'1 can be achieved by 1D_LUTpre in step S1002f.

Returning to FIG. 22, in step S1006', preheat pulse generation and synthesis is performed in the same manner as in step S1006 in FIG. 10. Then, processing proceeds to step S1007.

On the other hand, in step S1004-3, the pixels of the nth line are treated as the inner region IB and inner region output correction is performed. This is the same process as in step S1005. Then, the process proceeds to step S1006'.

Therefore, according to the embodiment described above, the difference between the preheating effect on the image start end IA and the preheating effect on the inner region IB can be reduced, improving the color development of the image start end IA.

Note that the 3D_LUTpre used in step S1002e has been described as generating only a preheat pulse, but in the case of Example 5 described later, this is changed to a 3D_LUTpre having a heating pulse for developing a specific color of n-line pixels. This configuration is the configuration of the 3D_LUT used in step S1004.

<Modification 1>
The heating pulse used at the image start edge IA is not limited to the above example, and other heating pulses may be used.

Figure 24 shows an example in which heating pulses based on the heating pulses shown in Figure 9 are used for application timings p0 to p8 of the image start end IA.

When executing a high color print job in step S615A in FIG. 8, by applying the flowchart in FIG. 22, it is possible to generate heating pulses with application timings p'0 to p'8 for the previous pixel area IW and application timings p0 to p8 for the image start IA shown in FIG. 24. It is also possible to generate heating pulses with application timings p0 to p8 for the internal area IB. Note that the contents of 3D_LUTpre and 1D_LUTpre for the previous pixel area IW are modified to have the preheat pulse widths shown in FIG. 24.

The contents of the 3D_LUT for the image start IA and the internal region IB are the same as the heating pulse shown in Figure 9. The contents of the 1D_LUTpre for the image start IA are changed to the preheat pulse width shown in Figure 24. The 1D_LUT for the internal region IB is the same as the heating pulse shown in Figure 9. Looking at the widths of Δt'1 and Δt"1 shown in Figure 24, Δt"1 is controlled to be narrowed, but it is also possible to control Δt'1 to be narrowed as shown in Figure 23.

Therefore, with the above configuration, even in high-color print jobs, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner area IB can be reduced, improving the color development of the image start edge IA.

In addition, for the heating pulses in the configurations shown in Figures 11 to 13, the color development at the image start point IA can be improved by applying the above-described application of Figure 9 to Figure 24.

<Modification 2>
Furthermore, the heating pulse used at the image start point IA is not limited to the above example, and other heating pulses may be used.

Figure 25 shows an example in which heating pulses based on the heating pulses shown in Figure 15 are used for application timings p0 to p8 of the image start end IA.

When executing a high-speed print job in step S615" in FIG. 14, by applying the flowchart in FIG. 22, it is possible to generate heating pulses with application timings p'0 to p'6 for the previous pixel area IW and application timings p0 to p6 for the image start IA shown in FIG. 25. It is also possible to generate heating pulses with application timings p0 to p6 for the internal area IB. Note that the contents of 3D_LUTpre and 1D_LUTpre for the previous pixel area IW are modified to obtain the preheat pulse width in FIG. 25.

The contents of the 3D_LUT for the image start IA and the internal region IB are the same as the heating pulse shown in Figure 15. The contents of the 1D_LUTpre for the image start IA are changed to the preheat pulse width shown in Figure 25. The 1D_LUT for the internal region IB is the same as the heating pulse shown in Figure 15. Looking at the widths of Δt'1 and Δt"1 shown in Figure 25, Δt"1 is controlled to be narrowed, but it is also possible to control Δt'1 to be narrowed as shown in Figure 23.

Therefore, with the above configuration, even in high-speed print jobs, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner area IB can be reduced, improving the color development of the image start edge IA.

In addition, for the heating pulses in the configurations shown in Figures 16 to 18, the color development at the image start point IA can be improved by applying the same technique as described above for Figure 15 to Figure 25.

In the third embodiment, an example was described in which the color development of the image start end IA in the transport direction of the recording medium (infrared image member) 10 shown in FIG. 19 is improved by generating a preheat pulse for the immediately preceding pixel area IW with reference to the pixel value of the image start end IA. In this embodiment, an example is described in which a preheat pulse is generated by correcting the pixel value of the immediately preceding pixel area IW according to the pixel value of the image start end IA.

Figure 26 is a diagram illustrating a correction table that stores pixel values of the previous pixel area IW after correction according to the pixel values of the image start IA when the previous pixel area IW is a white pixel.

This correction table stores the R, G, and B pixel values after correction of the previous pixel area IW for combinations of 256 gradations of R, G, and B at the image start IA. When the previous pixel area IW is a white pixel, the pixel value after correction of the previous pixel area IW can be calculated from the pixel value of the image start IA and the correction table shown in Figure 26. For example, for Y, M, C, R, G, B, and K,
Color Pixel value of the image start point IA Corrected value of the previous pixel area IW
RGB RGB
Y 255 255 0 255 255 240
M 255 0 255 255 196 255
C 0 255 255 128 255 255
R 255 0 0 255 240 240
G 0 255 0 128 255 128
B 0 0 255 196 196 255
K 0 0 0 240 240 240
It can be calculated as follows. The corrected value for the immediately preceding pixel region IW is used to generate a heating pulse in the same manner as for the image start end IA and the internal region IB. Note that, in the heating pulse based on the corrected value for the immediately preceding pixel region IW, it is preferable that the immediately preceding pixel region IW is not a visually noticeable color, and is a color that exerts a preheating effect on the color of the next image start end IA. Specifically, it is preferable that the pixel value has a similar hue to the pixel value of the image start end IA, and that the pixel value at the leading end of the image is just short of a visually noticeable color. As shown in FIG. 26, a pixel value with a higher brightness than the image start end IA is set as the corrected pixel value of the immediately preceding pixel region IW.

Figure 27 is a flowchart showing image processing for generating heating pulses to drive the recording head according to the fourth embodiment. This figure is a flowchart showing the details of the print job execution in step S616 in each of Figures 6, 8, and 14. Note that in Figure 27, the same step reference numbers are used for the same processing steps as those already explained in Figures 10 and 22, and their explanations are omitted. Here, only the processing steps unique to this embodiment are explained.

According to FIG. 27, after steps S1001 to S1002 are executed, if it is determined in step S1002-1 that the line currently being processed (line n) is in the non-coloring range and the next (n+1) line is in the coloring range, processing proceeds to step S1002a. Then, steps S1002a to S1002c are executed. Then, if it is determined in step S1002c that the pixel on line n is specific color data, in this example, "white," that is, R=255, G=255, B=255 (Yes), processing proceeds to step S1002h. On the other hand, if the pixel is not of a specific color (No), processing proceeds to step S1004.

In step S1002h, the nth line of pixels is processed as the previous pixel area IW. Specifically, using the correction table described in FIG. 26, the pixel values of the nth line corresponding to the previous pixel area IW are corrected using the n+1th line pixel values corresponding to the image start end IA. Then, processing proceeds to step S1004.

After performing the luminance density conversion in step S1004, the process performs output correction in step S1005, and further performs preheat pulse generation and synthesis in step S1006 .

Then, the process executes steps S1007 to S1008.

Comparing the example described above with FIG. 22, in this example, the luminance density conversion, output correction, preheat pulse generation, and synthesis processes corresponding to steps S1004 to S1006 can be performed in common regardless of the previous judgment results. This has the advantage that the tables referenced in steps S1004 to S1006 can also be common regardless of the judgment results.

Therefore, according to the embodiment described above, the difference between the preheating effect on the image start end IA and the preheating effect on the inner region IB can be reduced, improving the color development of the image start end IA.

In the third and fourth embodiments, an example was described in which if the previous pixel area IW contains white data, a preheat pulse is applied to the image start end IA to achieve a preheat effect. In this embodiment, an example is described in which a preheat pulse is applied to the previous pixel area IW, including white data, depending on the combination of specific colors in the previous pixel area IW and the image start end IA.

Figure 28 shows the preheat instruction and the table group number to be used according to the combination of specific colors of the previous pixel area IW and the image start end IA. Note that the flowchart shown in Figure 22, which has already been explained, can be used to execute this embodiment.

In step S1002c in FIG. 22, the table shown in FIG. 28 is referenced. For example, if the pixels on line n are R=255, G=255, B=0, and the pixels on line (n+1) are R=0, G=255, B=255, the preheat command is "Yes", so it is determined to be a specific color (Yes), and processing proceeds to step S1002d. Furthermore, in step S1002e, a 3D_LUT that can also have a heating pulse for producing a specific color as described in Example 1 is used as 3D_LUTpre. This 3D_LUT also includes a preheat pulse for the image start IA.

By predetermining a number for identifying the table group in conjunction with the 1D_LUTpre used in step S1002f for each specific color combination and managing it as in the table shown in FIG. 28, it is possible to set an appropriate table group by referencing the table. If the pixels on the nth line are R=255, G=255, B=0 (i.e., Y color) and the pixels on the (n+1)th line are R=0, G=255, B=255 (i.e., C color), the table group number is 12, and the table corresponding to this number is set for each process.

Figure 29 is a diagram explaining the heating pulse for a combination of specific colors of pixels on line n and pixels on line (n+1). In Figure 29, the color written on the left side indicates the print color of pixels on line n, and the color written on the right side indicates the print color of pixels on line (n+1).

As shown in FIG. 29, after applying heating pulses at application timings p'0 and p'1 to the n-th line pixel with R=255, G=255, B=0 (Y color), consider the heating pulse at application timing p5 to the (n+1)th line pixel with R=0, G=255, B=255 (C color). In this case, since the elapsed time is long, the C image forming layer 18 is not preheated sufficiently. Therefore, in the table of table group number 12 shown in FIG. 28, values are set for application timings p'6, p'7, and p'8 of the n-th line pixel that can generate preheat pulses for the (n+1)th line pixel. Furthermore, when the print color of the n-th line pixel is R and the (n+1)th line pixel is C, the time from application timing p'4 to p5 is long, so the preheat pulse for the (n+1)th line is set at application timing p'8.

On the other hand, if the color development of the nth line pixel provides a sufficient preheating effect for the color development of the (n+1)th line pixel, there is no need to set a preheat pulse for the (n+1)th line pixel in the nth line pixel. For example, as shown in FIG. 29, if the nth line pixel is K and the (n+1)th line pixel is C, there is no need to set a preheat pulse because the heating for coloring the nth line pixel provides sufficient preheating for the (n+1)th line pixel as well.

If the nth line pixel is R=0, G=0, B=0, and the (n+1)th line pixel is R=0, G=255, B=255, then according to the table in FIG. 28, the preheat command is "No." Therefore, in step S1002c in FIG. 22, it is determined that the color is not a specific color (No), and the process proceeds to step S1004.

Now, in FIG. 22, in steps S1005', S1006', and S1004-3, a table is used, and processing is performed using a table corresponding to the table group number corresponding to the set of n-th line pixel and (n+1)-th line pixel.

Therefore, according to the embodiment described above, the difference between the preheating effect on the image start end IA and the preheating effect on the inner region IB can be reduced, improving the color development of the image start end IA.

In the above explanation, an example of applying the processing of the flowchart shown in FIG. 22 was described, but the processing of this embodiment can be executed by applying the processing of the flowchart shown in FIG. 27.

That is, in step S1002c in FIG. 27, the table shown in FIG. 28 is referenced. For example, if the nth line pixel has R=255, G=255, B=0, and the (n+1)th line pixel has R=0, G=255, B=255, the preheat instruction is "yes", so it is determined to be a specific color (Yes), and processing proceeds to step S1002h. Also, if the nth line pixel has R=0, G=0, B=0, and the (n+1)th line pixel has R=0, G=255, B=255, the preheat instruction is "no", so it is determined to be not a specific color (No), and processing proceeds to step S1004.

When applying the flowchart shown in FIG. 27, it is sufficient to set a table group number so that the table used in step S1002h can be set according to a specific color combination.

In the third to fifth embodiments, examples were described in which a preheat pulse for the immediately preceding pixel region IW was set and applied. In this embodiment, an example is described in which the width or application timing of the preheat pulse for the immediately preceding pixel region IW is changed depending on the thermal history. The reason for changing the preheat pulse width or application timing depending on the thermal history is to reduce the preheat effect being excessive or insufficient. The thermal history is the ambient temperature of the infrared imaging member 10 detected by a thermistor, or the history of the estimated temperature of each layer in the immediately preceding pixel region IW of the infrared imaging member 10 based on the pattern of the heating pulse applied before the immediately preceding pixel region IW.

The temperature of each image-forming layer for each color developed can be estimated from the known activation temperatures of image-forming layers 14, 16, and 18 of the infrared imaging member 10 and the colors developed by printing various images in experiments. In addition, the temperature of a thermistor (not shown) provided in the recording device 40 at the time of color development during each printing is recorded, and the correspondence between the thermistor temperature and the estimated temperature of each image-forming layer is tabulated. Alternatively, the correspondence between the heating pulse pattern for the colors developed in the experiment and the estimated temperature of each image-forming layer may be tabulated.

When the print job of step S616 is executed, when the high color print job of step S615A is executed, and when the high speed print job of step S615" is executed, the temperature of the previous pixel area IW can be estimated from the temperature of the thermistor or the pattern of the heating pulse by referring to the table described above.

In this embodiment, the preheat pulse width and application timing of application timings p'0 to p'8 in Figures 20, 21, and 23 are changed depending on the estimated temperature. Specifically, multiple 3D_LUTpres that can calculate both the preheat pulse width and application timing described in Example 3 are prepared in advance according to temperature, and the 3D_LUTpre that corresponds to the estimated temperature is selected. In this way, the preheat pulse width and application timing of application timings p'0 to p'8 can be changed.

With this change, the higher the temperature, the narrower the preheat pulse width or the fewer the number of application timings.

Figure 30 shows an example of a preheat pulse and a subsequent heating pulse when the thermal history is at high temperature. In contrast, Figure 20 shows the preheat pulse width of an n-line pixel when the thermal history is at room temperature.

As can be seen by comparing FIG. 30 with FIG. 20, when the colors are Y, R, and K, the preheat pulse width Δt'1 at application timing p'8 is narrower in FIG. 30 than in FIG. 20. Also, when the colors are M and B, no preheat pulse is applied at application timing p'7 in FIG. 30. When the colors are C and G, no preheat pulse is applied at application timing p'6 in FIG. 30. Here, the two patterns of FIG. 20 and FIG. 30 are used for explanation, but three or more patterns with different preheat pulse widths or application timings may be used depending on the thermal history. Also, it is a good idea to set in advance in 3D_LUTpre the preheat pulse width and application timing that exert a preheating effect on the image start IA without the previous pixel area IW achieving visible color development, depending on the temperature.

Therefore, according to the embodiment described above, the difference between the preheating effect on the image start end IA and the preheating effect on the internal region IB can be reduced according to the thermal history, improving the color development of the image start end IA.

<Other Examples>
As with the internal region IB, in the third to sixth embodiments, the heating pulse for the image start end IA includes a preheat pulse. However, the present invention is not limited to this configuration. For example, preheating for the image start end IA may be performed only by the preheat pulse for the immediately preceding pixel region IW.

Figure 31 shows an example in which preheating of the image start end IA is performed using only the preheat pulse of the immediately preceding pixel area IW.

The characteristics of the preheat pulse shown in Figure 31 will be explained below in comparison with Figure 20.

In the case of Y, by applying the preheat pulse for the previous pixel area IW in Figure 20 and the pulse for the image start end IA earlier by Δt0, the image start end IA will only have an image formation pulse, as shown in Figure 31.

In the case of M, the preheat pulse in the immediately preceding pixel region IW in FIG. 20 is applied Δt0 earlier, and the pulse at the image start IA is applied Δt0 x 2 earlier, so that the image start IA only has an image formation pulse, as shown in FIG. 31. Here, the number of preheat pulses has been reduced from four to three because, unlike FIG. 20, the preheat pulses can be applied at continuous application timing, resulting in a high preheat effect, and leaving the number of preheat pulses at four would result in M developing color in the immediately preceding pixel region IW.

In the case of C, the preheat pulse in the immediately preceding pixel region IW in Figure 20 is applied Δt0 x 2 earlier, and the pulse at the image start IA is applied Δt0 x 8 earlier, so that the image start IA only has an image formation pulse, as shown in Figure 31. Here, the number of preheat pulses has been reduced from six to five because, unlike Figure 20, the preheat pulses can be applied at continuous application timing, resulting in a high preheat effect, and leaving the number of preheat pulses at six would result in C developing color in the immediately preceding pixel region IW.

In the case of R, by applying the preheat pulse for the previous pixel area IW in Figure 20 and the pulse for the image start IA earlier by Δt0, the image start IA will only have an image formation pulse, as shown in Figure 31.

In the case of G, by applying the preheat pulse in the immediately preceding pixel area IW in FIG. 20 and the pulse at the image start IA earlier by Δt0, the image start IA will only contain an image formation pulse, as shown in FIG. 31.

In the case of B, the preheat pulse in the immediately preceding pixel region IW in FIG. 20 is applied Δt0 earlier, and the pulse at the image start IA is applied Δt0 x 2 earlier, so that the image start IA only has an image formation pulse, as shown in FIG. 31. Here, the number of preheat pulses is reduced from four to three because, unlike FIG. 20, the preheat pulses can be applied at continuous application timing, resulting in a high preheat effect, and if the number of preheat pulses was left at four, M would develop color in the immediately preceding pixel region IW.

In the case of K, by applying the preheat pulse in the immediately preceding pixel area IW in FIG. 20 and the pulse at the image start IA earlier by Δt0, the image start IA will only contain an image formation pulse, as shown in FIG. 31.

As explained above, the color development at the beginning of the image IA can be improved by applying a pulse at the timing shown in Figure 31.

As explained above, the color development efficiency can be increased by setting the preheating pulse according to a combination of tristimulus values such as RGB and CMY. This improvement in color development efficiency can then be used to achieve high color development and for high-speed recording.

In order to simplify the process of determining whether or not a preheating pulse is required based on the combination of the three stimulus values, a configuration may be adopted in which the determination is whether or not Y = 0 (whether or not B = 255), and the preheating pulse is used if the determination result is Yes.

This is because the infrared imaging member 10 has a Y color-forming layer closest to its surface, which has the highest color-forming temperature, and therefore has a preheating effect on the coloring of other colors. Naturally, it goes without saying that if the infrared imaging member 10 has another color, for example an M color-forming layer closest to its surface, which has the highest color-forming temperature, it is appropriate to determine whether M=0 (G=255).

In addition, in the above-described embodiment, the recording device and the host device are separate, but the host device that supplies the image data may be an imaging device such as a digital camera. In this case, a device in which the recording device and the digital camera are integrated, that is, a recording device with a shooting function, is also included in the present invention.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

10 Recording medium (infrared imaging member), 12 Substrate, 13 Protective film layer,
14, 16, 18 Image forming layer, 15, 17 Spacer layer,
30 recording head, 31 substrate, 32 glaze, 33 convex glaze,
34 Resistor, 35 Heat sink, 40 Recording device, 41 Storage section, 42 Conveying roller,
43 platen, 44 discharge port, 50 host PC

Claims (23)

A recording device for forming an image on a sheet-like recording medium having a plurality of color-forming layers that correspond to a plurality of colors and that develop color in response to heating, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, comprising:
An input means for inputting image data from a host device;
A recording head having a plurality of heating elements;
a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse for causing the predetermined color forming layer to color, the second pulse being applied after the first pulse;
a pulse control means for controlling, when a specific color is to be developed, at least one of extending the pulse width of the first pulse and increasing the number of times the second pulse is applied so as not to develop color in other color-developing layers that are not used for reproducing the specific color;
the recording medium is formed with a first coloring layer that develops a yellow (Y) color, a second coloring layer that develops a magenta (M) color, and a third coloring layer that develops a cyan (C) color, in that order from the side that contacts the plurality of heat generating elements of the recording head;
the driving means drives the recording head based on the image data input by the input means to cause the first color forming layer, the second color forming layer, and the third color forming layer to develop colors in this order, thereby forming an image on the recording medium;
A recording device characterized in that the specific color is a color formed by coloring only the second color-forming layer, a color formed by coloring only the third color-forming layer, and a color formed by coloring both the second color-forming layer and the third color-forming layer . The input means inputs an instruction as to whether or not to further enhance color development,
2. The recording apparatus according to claim 1 , wherein when there is an instruction for high color development, control is performed by the pulse control means. The pulse control means
When the second color forming layer or the third color forming layer is to be colored independently, the pulse width of the first pulse used for preheating the color forming layer to be colored is made longer;
A recording device as described in claim 1 or 2, characterized in that when the second color-forming layer and the third color-forming layer are caused to color, the pulse width of the first pulse used to preheat the second color-forming layer is controlled to be longer. The recording device according to claim 1 or 2, wherein the pulse control means controls to lengthen the pulse width of the first pulse so that preheating of other color layers is performed at the same timing and with the same pulse width as preheating of the color layer to be colored at an earlier timing, regardless of the color layer to be colored. The recording device according to claim 1 or 2, characterized in that the pulse control means controls the application timing of the first pulse, which preheats the color-forming layer to be colored, to match the application timing of at least the second pulse, which is used to color a color-forming layer other than the color-forming layer. A recording device for forming an image on a sheet-like recording medium having a plurality of color-forming layers that correspond to a plurality of colors and that develop color in response to heating, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, comprising:
A recording head having a plurality of heating elements;
a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse for causing the predetermined color forming layer to color, the second pulse being applied after the first pulse;
a pulse control means for controlling, when a specific color is to be developed, at least one of extending the pulse width of the first pulse and increasing the number of times the second pulse is applied so as not to develop color in other color-developing layers that are not used for reproducing the specific color;
The recording device is characterized in that the pulse control means controls the application timing of the first pulse so that preheating of the color-forming layer to be colored is performed at the same timing as preheating of the color-forming layer to be colored at an earlier timing regardless of the color-forming layer to be colored, and controls the application timing of the first pulse for preheating the color-forming layer to be colored to match the application timing of at least the second pulse used for coloring a color- forming layer other than the color-forming layer. said input means further inputs an instruction as to whether or not to perform high speed recording;
2. The recording apparatus according to claim 1 , wherein when an instruction for high speed recording is given, control is performed by said pulse control means. The pulse control means
When the second color-forming layer or the third color-forming layer is caused to develop color independently, the pulse width of the first pulse used to preheat the color-forming layer to be developed is lengthened, and the first pulse having the lengthened pulse width is applied once immediately before the application of the second pulse for color development of the color-forming layer to be developed;
A recording device as described in claim 1 or 7, characterized in that, when the second color-forming layer and the third color-forming layer are caused to color, the pulse width of the first pulse used to preheat the second color-forming layer is lengthened, and the first pulse with the longer pulse width is applied once just before applying the second pulse to cause the second color-forming layer to color. The recording device according to claim 1 or 7, wherein the pulse control means controls so that the pulse width of the first pulse is lengthened so as to preheat the other color-forming layers at the same timing and with the same pulse width as the preheating of the color-forming layer to be colored at an earlier timing, regardless of the color-forming layer to be colored, and controls so as to apply the first pulse with the longer pulse width once. The recording device according to claim 1 or 7, characterized in that the pulse control means controls the application timing of the first pulse, which preheats the color-forming layer to be colored, to coincide with at least the second pulse, which is used to color a color-forming layer other than the color-forming layer. The recording device described in claim 1 or 7, characterized in that the pulse control means controls the application timing of the first pulse so that preheating of the color layer to be colored is performed at the same timing as preheating of the color layer to be colored at an earlier timing regardless of the color layer to be colored, and controls the application timing of the first pulse for preheating the color layer to be colored to match the application timing of at least the second pulse used for coloring a color layer other than the color layer to be colored. 12. The recording apparatus according to claim 1 , wherein a host device for outputting image data is included in the recording apparatus. 13. The recording apparatus according to claim 1, wherein the pulse control means applies the first pulse and the second pulse to the same pixel. A recording control method for a recording device having an input means for inputting image data from a host device, heating a sheet-like recording medium having a plurality of superposed color forming layers, the plurality of color forming layers corresponding to a plurality of colors and coloring in response to heating, by a recording head having a plurality of heating elements, to cause a desired color forming layer among the plurality of color forming layers to color and form an image on the recording medium, comprising:
a control step of controlling at least one of lengthening a pulse width of the first pulse and increasing the number of times the second pulse is applied, so as not to cause other color layers not used for reproducing the specific color to develop color, when driving each of the plurality of heating elements of the recording head to develop a specific color using a first pulse for preheating a predetermined color layer and a second pulse applied after the first pulse for coloring the predetermined color layer ,
the recording medium is formed with a first coloring layer that develops a yellow (Y) color, a second coloring layer that develops a magenta (M) color, and a third coloring layer that develops a cyan (C) color, in that order from the side that contacts the plurality of heat generating elements of the recording head;
driving the recording head based on image data input by the input means to cause the first color-forming layer, the second color-forming layer, and the third color-forming layer to develop colors in this order, thereby forming an image on the recording medium;
A recording control method, characterized in that the specific color is a color formed by coloring only of the second color-forming layer, a color formed by coloring only of the third color-forming layer, and a color formed by coloring both of the second color-forming layer and the third color-forming layer . A recording control method for a recording device, comprising the steps of: heating a sheet-shaped recording medium having a plurality of superposed color forming layers, the plurality of color forming layers corresponding to a plurality of colors and each coloring in response to heating, by a recording head having a plurality of heating elements, and causing a desired color forming layer among the plurality of color forming layers to develop color, thereby forming an image on the recording medium, the method comprising the steps of:
a control step of controlling at least one of lengthening a pulse width of the first pulse and increasing the number of times the second pulse is applied, so as not to cause other color layers not used for reproducing the specific color to develop color, when driving each of the plurality of heating elements of the recording head to develop a specific color using a first pulse for preheating a predetermined color layer and a second pulse applied after the first pulse for coloring the predetermined color layer ,
The control step includes controlling the application timing of the first pulse so that preheating of the color layer to be colored is performed at the same timing as preheating of the color layer to be colored at an earlier timing, regardless of the color layer to be colored, and controlling the application timing of the first pulse for preheating the color layer to be colored to match the application timing of at least the second pulse used for coloring a color layer other than the color layer to be colored . A recording device for forming an image on a sheet-like recording medium having a plurality of color-forming layers that correspond to a plurality of colors and that develop color in response to heating, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, comprising:
A recording head having a plurality of heating elements;
a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse applied after the first pulse for causing the predetermined color forming layer to develop a color;
a conveying means for conveying the recording medium in a first direction relative to the recording head;
a control means for controlling the driving means to use the first pulse for a first pixel located in an image non-forming area of the recording medium, and to use the second pulse for a second pixel located in an image forming area of the recording medium and recorded after the first pixel ;
the control means at least either changes a duty ratio of the first pulse used at the position of the first pixel or changes an application time of the first pulse, depending on whether the color-producing layer that produces color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer, based on image data;
The recording device is characterized in that, when there are multiple desired color-forming layers, the control means reduces the duty ratio of the first pulse or shortens the application time of the first pulse in order to preheat a color-forming layer located deep inside . the first pixel and the second pixel are consecutive pixels in the first direction,
17. The recording apparatus according to claim 16 , wherein the second pixel is a pixel located at a position where an image can be formed first in the image forming area with respect to the first direction. 18. A recording apparatus according to claim 16 , wherein none of the plurality of color forming layers develops color at the position of the first pixel by driving the driving means using the first pulse. 19. The recording apparatus according to claim 16 , wherein the first pixel is a white pixel. A recording device as described in any one of claims 16 to 18, characterized in that the control means changes the value of the first pixel to a value other than white based on the image data used to form an image in the second pixel , so as not to cause color to be produced in the multiple color layers. 21. The recording apparatus according to claim 20, wherein the control means controls so as to perform preheating by the first pulse when a specific combination of a value of the second pixel and a value of the first pixel is found. The method further includes acquiring a thermal history of the first pixel,
22. The recording apparatus according to claim 16 , wherein the duty ratio of the first pulse is reduced or the application time of the first pulse is shortened based on the thermal history acquired by the acquisition unit. A recording control method for a recording device, comprising: heating a sheet-shaped recording medium having a plurality of superposed color forming layers, the plurality of color forming layers corresponding to a plurality of colors and coloring in response to heating, by a recording head having a plurality of heating elements, to cause a desired color forming layer among the plurality of color forming layers to color, thereby forming an image on the recording medium,
a first pulse for preheating a predetermined color-forming layer and a second pulse for causing the predetermined color-forming layer to color, the second pulse being applied after the first pulse, when driving each of the plurality of heat generating elements of the recording head;
a control is performed so that the first pulse is used for a first pixel located in an image non-forming area of the recording medium, and the second pulse is used for a second pixel located in an image forming area of the recording medium and recorded after the first pixel;
based on input image data, at least one of changing a duty ratio of the first pulse used at the position of the first pixel or changing an application time of the first pulse depending on whether the color-producing layer that produces color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer ;
A recording control method characterized in that, when there are multiple desired color-forming layers, the duty ratio of the first pulse is reduced or the application time of the first pulse is shortened in order to preheat a color-forming layer located deep inside .

Images