JP2622000B2 - Recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording an image on a recording medium by driving a recording head such as a thermal head to generate heat.

[Prior Art] In a conventional thermal printer or the like that records an image by driving a thermal head to generate heat, the thermal head is provided with a temperature sensor such as a thermistor for detecting the temperature of the thermal head. The energy applied to the thermal head is adjusted accordingly. This means that, for example, an analog signal from a temperature sensor is input and converted into digital, and the pulse width applied to the thermal head is determined by referring to a table storing the applied pulse width corresponding to the digital value. It is going by.

[Problems to be Solved by the Invention] However, in general, the temperature sensor is mounted at a place slightly away from the row of heating elements due to the structure of the thermal head. For this reason, the temperature of the thermal head is detected by the temperature sensor later than the actual temperature change of the heating element, and it is not sufficient to simply adjust the energy applied to the thermal head by the output of the temperature sensor.

The present invention has been made in view of the above-described conventional example, and detects the temperature of a printhead at regular time intervals, and if the current printhead temperature is higher than the past printhead temperature, the current printhead temperature Is corrected to a temperature higher than the actual detected temperature, and if the current printhead temperature is lower than the past printhead temperature, the current printhead temperature is corrected to a temperature lower than the actual detected temperature. A recording apparatus for recording an image on a recording medium by stabilizing the recording density even if the temperature of the recording head fluctuates by determining and applying energy applied to the recording head in accordance with the corrected temperature of the recording head. The purpose is to provide.

Means for Solving the Problems In order to achieve the above object, a recording apparatus of the present invention has the following configuration. That is, a recording apparatus for recording an image on a recording medium by driving a recording head to generate heat, comprising: a temperature detection unit that detects a temperature of the recording head at regular time intervals; and a current detection unit that detects the temperature of the recording head. If the temperature of the recording head is higher than the past temperature of the recording head, the current temperature of the recording head is corrected to a temperature higher than the actual detected temperature, and the current temperature of the recording head is When the temperature is lower than the temperature of the recording head, a correction unit that corrects the current temperature of the recording head to a temperature lower than the actual detected temperature, and according to the current temperature of the recording head corrected by the correction unit. Determining means for determining energy to be applied to the recording head; and driving means for driving the recording head with the energy determined by the determining means. And butterflies.

[Operation] In the above configuration, the temperature of the printhead is detected at regular time intervals, and if the detected current temperature of the printhead is higher than the temperature of the past printhead, the current temperature of the printhead is detected. If the current printhead temperature is lower than the past printhead temperature, the current printhead temperature is corrected to a lower temperature than the actual detected temperature. Then, the energy to be applied to the print head is determined according to the corrected current temperature of the print head, and the print head is operated with the determined energy.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, a thermal printer using a thermal head will be described as an example.However, the present invention is not limited to this, and an image is recorded by discharging ink droplets by heat generation. Of course, the present invention can be applied to an ink jet printer or the like.

[Explanation of Facsimile Apparatus (FIGS. 1 to 4)] FIGS. 1 and 2 are diagrams showing an example in which a thermal transfer printer using an embodiment of the present invention is applied to a facsimile apparatus. Block diagram showing a schematic configuration of the facsimile apparatus,
FIG. 2 is a side sectional view of the facsimile apparatus.

 First, the schematic configuration will be described with reference to FIG.

In the figure, a reading unit 100 photoelectrically reads a document and outputs it as a digital image signal to a control unit 101. The reading unit 100 includes a document transport motor, a CCD image sensor, and the like. 101
Is a control unit for controlling the entire apparatus, and its configuration will be described.
A line memory 110 stores the image data of each line of the image data. The line memory 110 stores one line of image data from the reading unit 100 when transmitting or copying a document, and decodes the image data when receiving image data. One line data of the received image data is stored. Then, the stored data is output to the recording unit 102, so that an image is formed. An encoding / decoding unit 111 encodes image information to be transmitted by MH encoding or the like, and decodes received encoded image data to convert the image data into image data. Reference numeral 112 denotes a buffer memory for storing transmitted or received encoded image data. Each unit of the control unit 101 and the entire apparatus are controlled by a CPU 113 such as a microprocessor. The control unit 101 includes, in addition to the CPU 113, a ROM 114 that stores a control program of the CPU 113 and various data, a RAM 115 that temporarily stores various data as a work area of the CPU 113, and the like.

Reference numeral 114a denotes a table provided in the ROM 114, which stores pulse width information applied to the thermal head 13 in correspondence with temperature information (digital value) from the temperature sensor 20 attached to the thermal head 13 having a plurality of heating elements. doing. 115a, 1
Reference numeral 15b denotes a memory area provided in the RAM 115. The previous temperature value is stored in the M115a, and the temperature information of the thermal head 13 measured this time is temporarily stored in the DT 115b.

A recording unit 102 includes a thermal line head 13 and records an image on recording paper by a thermal recording method. This configuration will be described later in detail with reference to FIG. Reference numeral 20 denotes a temperature sensor attached to the thermal head 13. A signal from the temperature sensor is input to the control unit 101, converted into a digital signal by the A / D converter 18, and input to the CPU 113. Reference numeral 103 denotes an operation unit including various function instruction keys for starting transmission and the like and a telephone number input key, and reference numeral 104 denotes a display unit which normally displays various functions provided in the operation unit 103 and the state of the apparatus. Ten
Reference numeral 5 denotes a power supply unit for supplying power to the entire apparatus. Reference numeral 106 denotes a modem (modulator / demodulator) that performs AC / DC conversion, 107 denotes a network control unit (NCU) that controls communication with a line, and 108 denotes a telephone.

Next, the configuration of the entire apparatus will be described in detail with reference to FIG. The parts common to FIG. 1 are indicated by the same reference numerals.

In the figure, reference numeral 10 denotes a roll paper in which a recording paper 11 which is plain paper is wound in a roll shape around a core 10a. This roll paper 10
The recording paper 11 is rotatably accommodated in the apparatus so that the recording paper 11 can be supplied to the thermal head 13 by rotation of a platen roller 12 rotated by a recording paper transport motor in the direction of the arrow. A roll paper loading unit 10b removably loads the roll paper 10. In addition, 12
Is a platen roller which conveys the recording paper 11 in the direction of arrow b and presses the recording paper 11 between itself and the heating element 132 of the thermal head 13. The recording paper 11 on which image recording has been performed by the heat generated by the thermal head 13 is conveyed in the direction of discharge rollers 16a and 16b by further rotation of the platen roller 12, and when image recording for one page is completed, the cutters 15a and
It is cut into pages by the engagement of 15b. A spring 21 presses the thermal head 13 against the platen roller 12 via the recording paper 11. Reference numeral 22 denotes a recording sheet sensor for detecting the presence or absence of a recording sheet.

 Next, the configuration of the reading unit 100 will be described.

In the figure, reference numeral 30 denotes a light source for irradiating an original 32, and light emitted from the light source 30 and reflected by the original 32 is transmitted through an optical system (mirror 5).
0, 51, and a lens 52), and is input to the CCD sensor 31 and converted into an electric signal. The original 32 is transported by transport rollers 53, 54, 55, 56 driven by a not-shown original transport motor in accordance with the reading speed of the original 32. In addition,
Reference numeral 57 denotes a document loading table, and a plurality of documents 32 loaded on the loading table 57 are separated one by one by the cooperation of the conveying roller 54 and the pressing and separating piece 58, and are transferred to the reading unit 100. Conveyed.

Reference numeral 41 denotes a control board that forms a main part of the control unit 101, and various control signals are output from the control board 41 to each unit. Reference numeral 106 denotes a modem board unit for performing communication processing, and 107 denotes an NCU board unit having a function of relaying to a telephone line.

The operation of the above configuration will be described. When an image signal is input from the modem 106, the control unit 101 decodes the image signal, stores it in the line memory 110, and gives an instruction to start image recording to the recording unit 102. The recording data is serially transferred from the control unit 101 to the thermal head 13 and stored therein. Next, the control unit 101 outputs a phase excitation signal to a recording paper transport motor by a motor drive circuit (not shown), and transports the recording paper 11 in the direction of arrow b. After that, a strobe signal is output to the thermal head 13 and the heating element 13 of the thermal head 13 is output.
By applying heat to block 2 and driving it by heating,
The recording process for one line is performed.

FIG. 3 is a diagram showing an example of applied pulse width information corresponding to the A / D converted value of the temperature data stored in the table 114a. Here, pulse width information applied to the thermal head 13 is stored corresponding to the output value of the A / D converter 18.

[Explanation of Recording Process (FIGS. 4 to 6)] FIG. 4 is a flowchart showing a recording process in the facsimile apparatus of the embodiment, and a control program for executing this process is stored in the ROM 114 of the control unit 101. I have. In addition,
This process is started when the image data for one line to be recorded is stored in the line memory 110 and the recording operation can be started.

First, in step S1, one line of print data is output serially to the thermal head 13. Next, in step S2, the temperature data stored in the memory DT115b is read, and in step S3, the pulse width applied to the thermal head 13 is determined with reference to the table 114a. In step S4, one block of the heating element 132 of the thermal head 13 is energized with the pulse width determined in step S3, and in step S5, the thermal head 13 is turned on.
It is checked whether or not all the heating elements 132 are energized.

In step S5, all heating elements 132 of thermal head 13
When recording is completed for one line, the flow advances to step S6 to convey the recording paper 11 by one line. Next, it is checked in step S7 whether the image recording of one page has been completed. If the image recording of one page has not been completed, the process proceeds to step S8, and the image data of the next line is transferred to the thermal head 13. In addition, this 1
The line portion has a length corresponding to the length of one dot recorded by the thermal head 13, and is, for example, 1 / 15.4 mm in the case of a facsimile apparatus.

When the image recording for one page is completed in step S7, the step
Proceeding to S9, the recording paper 11 is fed in the direction of the paper discharge rollers 16a and 16b by a predetermined amount, and the rear end of the recording paper on which image recording has been performed is transported to the cutting position of the cutter 15. Then, the cutters 15a and 15b are driven and meshed to cut the recording paper 11 into pages. Next, step S1
At 0, the recording paper cut by the discharge roller 16 is discharged out of the apparatus. At the same time, in step S11, the platen roller 1
2 is reversed, and the recording paper 11 is returned by a distance corresponding to the interval between the thermal head 13 and the cutter 15 so that the leading end thereof comes to the next image recording position, and the image recording processing for one page is completed.

FIG. 5 is a flowchart showing a temperature detection process in the facsimile apparatus of the embodiment. This process may be started by an interrupt signal at a predetermined time interval output from a timer (not shown) or the like.
It may be executed before S2. Here, the case of an interrupt will be described.

When an interrupt occurs, the process proceeds to step S21, where the temperature sensor 2
Temperature information of thermal head 13 detected by 0 (T)
Is input from the A / D converter 18 and the memory 115a is inputted in step S22.
(M). Wait for the predetermined time to elapse in step S23, and after the predetermined time elapses, proceed to step S24,
The temperature data (T ₁ ) from the A / D converter 18 is input again.

Next, the process proceeds to step S25, and the temperature data (T ₁ ) is corrected by T ₁ + (T ₁ -M). Here, M is temperature information stored in the memory 115a before a predetermined time has elapsed, T ₁
Represents the temperature information of the thermal head 13 after a predetermined time has elapsed after measuring the value of M. And step
The temperature information (T ₁ ) corrected in S26 is stored in the memory DT115b.

As described above, by adding the temperature change value (T ₁ -M) of the thermal head 13 after a predetermined time has elapsed after measuring M to the latest temperature information (T ₁ ), the corrected temperature information is obtained. The pulse width applied to the thermal head 13 is determined using (T ₁ ).

FIG. 6 is a diagram showing the relationship between the temperature data of the thermal head 13 and the pulse width applied.

Now, assume that the temperature detected by the temperature sensor 20 at the time of reading at step S21 in FIG. 5 is 40 ° C. Temperature information (T = 50) is input. Then, if the temperature at the time of reading in step S24 is 42 ° C. after the elapse of a predetermined time, the data is inputted with T ₁ = “52”. This gives T ₁ = 52 + (5
2−50) = 54 (corresponding to the temperature of the thermal head 13 of 44 ° C.) and stored in the DT.

Thus, in step S2 in FIG. 4, the temperature data (T ₁ = 54) is read from the memory DT, and based on this value, the pulse width applied to the thermal head 13 is set to “0.
36ms ".

As described above, in the present embodiment, the actual temperature of the thermal head and the pulse width to be applied to the thermal head 13 based on the temperature change state are determined to more correspond to the actual temperature of the heating element of the thermal head. Power supply control can be performed. In addition, to control the energization of the thermal head,
In addition to changing the applied pulse width, the applied voltage, applied current, or the number of applied pulses may be changed.

In this embodiment, the temperature change of the thermal head after a predetermined time is detected, but the energy applied to the thermal head may be changed based on the temperature change of each line.

In this embodiment, the case of the line type thermal head has been described. However, the present invention is not limited to this. For example, even in the case of the serial type thermal head, the temperature change of the thermal head is similarly considered. Thus, the amount of applied energy can be controlled.

As described above, according to this embodiment, the energy applied to the thermal head is appropriately controlled by correcting the temperature information of the actually detected thermal head according to the temperature change state of the thermal head, It is possible to stabilize the recording density and suppress an extreme rise in temperature of the thermal head.

In the above description, a thermal printer using a thermal head has been described. However, the present invention is not limited to this. For example, recording of an image is performed by causing a heating element to generate heat and causing ink to fly. Needless to say, the present invention can be applied to an ink jet recording apparatus. Among them, by applying at least one drive signal that gives a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer as a heating element, heat is applied to the electrothermal transducer by applying heat. Thermal energy is generated in the heat converter, and the film is boiled on the heat-acting surface of the recording head to form air bubbles in the ink. Of course, the present invention can be applied to a valve jet recording apparatus or the like which discharges ink through a discharge port provided in the ink jet head by the growth and contraction of the bubble. Therefore, the recording head is not limited to the thermal head, but includes, for example, an ink jet head.

[Effects of the Invention] As described above, according to the present invention, the printhead temperature is detected at regular time intervals, and if the current printhead temperature is higher than the past printhead temperature, the current printhead is detected. Is corrected to a temperature higher than the actual detected temperature,
If the current printhead temperature is lower than the past printhead temperature, the current printhead temperature is corrected to a temperature lower than the actual detected temperature, and the printhead is corrected according to the corrected printhead temperature. By determining the energy to be applied to the recording and recording, there is an effect that the recording density can be stabilized and the image can be recorded on the recording medium even if the temperature of the recording head fluctuates.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a facsimile apparatus according to an embodiment, FIG. 2 is a sectional side view showing a mechanism of the facsimile apparatus according to the embodiment, and FIG. FIG. 4 is a flowchart showing recording processing in the facsimile apparatus of the embodiment, FIG. 5 is a flowchart showing temperature detection processing in the facsimile apparatus of the embodiment, and FIG. 6 is temperature data and its digital data. FIG. 4 is a diagram illustrating an example of a relationship between a value and an applied pulse width. In the figure, 10 ... roll-shaped recording paper, 11 ... recording paper, 12 ... platen roller, 13 ... thermal head, 15 ... cutter,
16 ... discharge roller, 18 ... A / D converter, 20 ... temperature sensor, 22 ... recording paper presence / absence sensor, 100 ... reading unit, 101 ...
Control unit 102 Recording unit 103 Operation unit 104 Display unit 105 Power supply 106 Modem 107 NCU 110
… Line memory, 111… coding / decoding unit, 112… buffer memory, 113… CPU, 114… ROM, 114a… table, 115… RAM, 132… heating resistor (heating element) is there.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takehiro Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tomoyuki Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-62-176365 (JP, A) JP-A-61-173961 (JP, A) JP-A-62-116168 (JP, A) JP-A-63-1557 (JP, A A) JP-A-63-149168 (JP, A) JP-A-64-14055 (JP, A) JP-A-59-73964 (JP, A) JP-A-61-249768 (JP, A) JP-A-61-249768 −252165 (JP, A)

Claims (3)

(57) [Claims] 1. A recording apparatus for recording an image on a recording medium by driving a recording head to generate heat, comprising: a temperature detecting means for detecting a temperature of the recording head at regular time intervals; If the current temperature of the print head is higher than the past temperature of the print head, the current temperature of the print head is corrected to a temperature higher than the actual detected temperature, and the current temperature of the print head is corrected. Correction means for correcting the current temperature of the recording head to a temperature lower than the actual detected temperature when the temperature of the recording head is lower than the past temperature of the recording head; and the current temperature of the recording head corrected by the correction means Determining means for determining the energy to be applied to the recording head according to the following, and driving means for driving the recording head with the energy determined by the determining means. A recording device, characterized in that: 2. The recording apparatus according to claim 1, wherein said recording head is a thermal head having a plurality of heating elements. 3. The recording head according to claim 2, wherein the recording head is a bubble ink jet head that forms bubbles in the ink by the heat generated by a heating element and discharges the ink through a discharge port by the growth and contraction of the bubbles. Item 2. The recording device according to Item 1.