JP6961364B2 - Inkjet recording device and inkjet recording method - Google Patents

Description

The present invention relates to a technique for suppressing the influence of cockling (waviness of a recording medium) that occurs in a recording medium when recording an image in a multipath type inkjet recording apparatus using a line recording head.

The inkjet recording apparatus described in Patent Document 1 includes a set of inkjet recording heads capable of ejecting the same ink as line recording heads extending in the width direction of the recording medium. By reciprocating the recording medium to the recording head a plurality of times, the image is recorded on the recording medium in a plurality of times. Further, by moving the recording head in the width direction of the recording medium, pixels on the same raster along the transport direction of the recording medium are recorded by using a plurality of nozzles in the recording head, and the ink ejection characteristics of each nozzle can be measured. The effect of variation can be suppressed.

Patent No. 4715209

However, in the recording apparatus described in Patent Document 1, when the amount of ink applied to the unit area of the recording medium is large, a large amount of ink is applied in a short time, so that the recording medium is cocked. The recording medium may come into contact with the recording head. When such contact occurs, the quality of the recorded image may be deteriorated and the recording head may be damaged.

An object of the present invention is to provide an inkjet recording apparatus and an inkjet recording method capable of suppressing the influence of cockling when an image is recorded in a plurality of times with a plurality of reciprocating transports of a recording medium. be.

The inkjet recording apparatus of the present invention is an inkjet recording apparatus that records an image on the recording medium in a plurality of times by reciprocating the recording medium a plurality of times through a position facing a recording head capable of ejecting ink. The method for recording an image in a recording area of the recording medium in which the amount of ink applied per unit area is equal to or greater than a predetermined amount according to the amount of ink applied per unit area of the recording medium. The reciprocating transport amount of the recording medium is shorter than the reciprocate transport amount when the image is recorded in the recording area of the recording medium in which the amount of ink applied per unit area is less than a predetermined amount in a plurality of times. As described above, it is characterized by providing a changing means for changing the reciprocating transport amount of the recording medium.

According to the present invention, by changing the reciprocating transfer amount of the recording medium according to the amount of ink applied per unit area of the recording medium, the influence of cockling is suppressed, the quality of the recorded image is deteriorated, and the recording is performed. Damage to the head can be suppressed.

It is a perspective view of the main part of the recording apparatus in 1st Embodiment of this invention. It is sectional drawing at the time of the recording operation of the recording apparatus of FIG. It is sectional drawing at the time of cleaning operation of the recording apparatus of FIG. It is explanatory drawing of the structure of a recording head. It is explanatory drawing of the configuration example of a different recording head. It is a block diagram of the control system of a recording device. It is explanatory drawing of the multipath recording system using a line recording head. It is explanatory drawing of the multipath recording system using a line recording head. It is explanatory drawing of the transport amount change operation of a recording medium. It is explanatory drawing of the transport amount change operation of a recording medium. It is explanatory drawing of the transport amount changing operation of the recording medium in the 2nd Embodiment of this invention. It is explanatory drawing of the transport amount changing operation of the recording medium in the 2nd Embodiment of this invention. It is explanatory drawing of the transport amount changing operation of a recording medium in 3rd Embodiment of this invention. It is explanatory drawing of the transport amount changing operation of a recording medium in 3rd Embodiment of this invention. It is explanatory drawing of the transport amount of the recording medium in 4th and 5th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In this specification, the term "record" is not limited to the case of forming significant information such as characters and figures, and may be significant or involuntary. Further, "recording" is to form an image, a pattern, a pattern, etc. on a wide range of recording media, or to process the medium, regardless of whether or not it is manifested so that it can be visually perceived by humans. The case shall also be represented. The term "recording medium" refers not only to paper used in general recording devices, but also to a wide range of materials such as cloth, plastic film, metal plate, glass, ceramics, wood, and leather that can accept ink. Shall be. Furthermore, "ink" (sometimes referred to as "liquid") should be broadly interpreted as in the definition of "recording" above. Therefore, by being applied onto a recording medium, it is used for forming images, patterns, patterns, etc., processing the recording medium, or processing ink (for example, coagulation or insolubilization of a coloring material in the ink applied to the recording medium). It shall represent the liquid that can be served. Furthermore, the term "nozzle" is a general term for the ejection port, the liquid passage communicating with the ejection port, and the element for generating energy used for ink ejection, unless otherwise specified.

(First Embodiment)
FIG. 1 is a perspective view of a main part of the inkjet recording device (hereinafter, also referred to as “recording device”) 1 of the present embodiment, FIG. 2 is a cross-sectional view of the recording device 1 during a recording operation, and FIG. 3 is a cleaning operation. It is sectional drawing of the recording apparatus 1 at the time.

The recording device 1 of this example uses a long line recording head (hereinafter, also referred to as “recording head”) 2 while transporting the sheet-shaped recording medium 4 in the transport direction (first direction) indicated by the arrow X. It is a line printer that records images. The recording medium 4 can be conveyed in both the forward direction of the arrow X1 and the reverse direction of the arrow X2. The recording device 1 uses a holder that holds a recording medium 4 such as continuous paper wound in a roll, a transfer unit 7 that conveys the recording medium 4 in a transfer direction at a predetermined speed, and a recording head 2. A recording unit 3 for recording an image is provided. The recording medium 4 is not limited to continuous roll paper, and may be a cut sheet.

The recording device 1 is provided with a cleaning unit 6 for cleaning the nozzle surface of the recording head 2 with a wiper. Further, at a position on the downstream side of the recording unit 3 in the direction of the arrow X1, a cutter unit for cutting the recording medium 4 and a paper ejection tray are provided along the transport path of the recording medium 4 (both not shown). .. The recording unit 3 is provided with a recording head 2 corresponding to different ink colors. In this example, four recording heads 2 corresponding to four color inks of C (cyan), M (magenta), Y (yellow), and K (black) are provided. The number of recording heads 2 deployed and the number of ink colors used for recording are not limited to this example.

The ink of each color is supplied from the corresponding ink tank (not shown) to the corresponding recording head 2 via the ink tube (not shown). The four recording heads 2 are integrally held by the head holder 5, and the head holder 5 is provided with the head holder 5 so that the distance between the four recording heads 2 and the surface of the recording medium 4 can be changed. A mechanism for moving up and down along the Z direction of the arrow (first moving direction) is provided. Further, the head holder 5 is provided with a mechanism for moving the head holder 5 in the arrow Y direction (second moving direction) intersecting (in this example, orthogonal) with the conveying direction of the recording medium 4. There is.

The cleaning unit 6 has four wiper units 9 corresponding to the four recording heads 2. The cleaning unit 6 is configured to slide in the arrow A direction (third moving direction) along the conveying direction of the recording medium 4 by a drive motor (not shown). During the recording operation of the recording device 1, the cleaning unit 6 is located downstream of the recording unit 3 in the direction of the arrow X1 as shown in FIGS. 1 and 2. On the other hand, during the cleaning operation, as shown in FIG. 3, the cleaning unit 6 is located directly below the recording head 2 in the recording unit 3. The cleaning unit 6 moves in the direction of arrow A (third moving direction) in FIGS. 2 and 3.

4A and 4B are explanatory views of the recording head 2, FIG. 4A is a view of the recording head 2 as viewed from the transport direction of the recording medium 4, and FIG. 4B is from the lower side in FIG. 4A. It is a bottom view which looked at the recording head 2. As an inkjet method for ejecting ink from the nozzle of the recording head 2, various methods using ejection energy generating elements such as an electric heat conversion element (heater), a piezo element, an electrostatic element, or a MEMS element can be adopted. can. The recording head 2 is a full-line recording head in which a nozzle row 42 is formed over a range that covers the maximum width of the recording medium 4 that is expected to be used. The extending direction of the nozzle row 42, that is, the arrangement direction of the nozzles capable of ejecting ink is a direction intersecting (in this example, orthogonal) with the transport direction of the arrow X. A nozzle chip 41 is provided on the base substrate 40 of the recording head 2. The nozzle tip 41 has a nozzle surface on which the nozzles of the nozzle row 42 are formed, and a nozzle substrate in which a discharge energy generating element corresponding to each nozzle is embedded. In the case of this example, four nozzle rows 42 are formed in parallel.

Further, the wiper holder 44 provided with the wiper blade 43 is moved in the arrow Y direction by the drive belt 46 while being guided by the shaft 45. As a result, the ink and dust adhering to the nozzle surface of the recording head 2 are wiped off by the wiper blade 43.

In the recording head 2 of FIG. 4B, one nozzle chip 41 is arranged on one base substrate 40. However, the recording head 2 may have a form in which a plurality of nozzle chips 41 are arranged on one base substrate 40 as shown in FIG. 5A, and a plurality of recording heads 2 may be arranged as shown in FIG. 5B. The base substrate 40 may be connected by a support member 48.

FIG. 6 is a block of the control system of the recording device 1.

The CPU 501 reads a program that controls the system control of the recording device 1 from the ROM 502 and executes it, and controls the entire system according to the program. The RAM 512 is used as a work area for developing a program. That is, the RAM 512 temporarily stores data and input data required for processing executed by the CPU 501. The CPU 501 also controls the operations of the cleaning unit 6, the transport unit 7, and the like.

Further, the CPU 501 controls the recording operation by the recording head 2 through the drive circuit 507, the binarization circuit 508, and the image processing unit 509. The image processing unit 509 performs predetermined image processing on the input color image data to be recorded. That is, the image processing unit 509 executes data conversion for mapping the color gamut reproduced by the input image data of each RGB color component into the color gamut reproduced by the recording device 1, for example. Further, the image processing unit 509 performs a process of obtaining color separation data (CMYK component density data) corresponding to the combination of inks that reproduce the colors indicated by each data based on the converted data, and is decomposed into each color. Gradation conversion is performed for each of the color separation data.

The binarization circuit 508 performs halftone processing or the like on the multi-value density image data converted by the image processing unit 509, and then converts it into binary data (bitmap data). The drive circuit 507 ejects ink from the nozzle of the recording head 2 according to the binar data obtained by the binarization circuit 508 and the like.

The defective nozzle complementing unit 510 executes a process of generating complementary data for defective nozzles (hereinafter, also referred to as “complementary processing”). The defective nozzle detection unit 511 detects a nozzle (defective nozzle) in which the ink droplet ejection state is in a defective state among the plurality of nozzles formed in the recording head 2. At that time, the CPU 501 drives the recording head 2 via the drive circuit 507 based on the pattern data read from the ROM 502, and controls the transport unit 7 and the like related to the recording operation, so that the recording medium 4 is defective. Record the pattern for nozzle detection. The defective nozzle is detected by reading the recorded pattern by the defective nozzle detection unit 511.

FIG. 7 is an explanatory diagram of a multipath recording method using a line recording head.

In the single-pass recording system using a line recording head, an image is recorded with one transfer of the recording medium in one direction without moving the recording medium back and forth in the transfer direction. In this case, especially in a recording area where inks are densely applied, a bleeding phenomenon may occur in which inks of each color bleed into each other. This bleeding phenomenon is a phenomenon in which when ink droplets are shot onto a recording medium within a short period of time, the inks of each color are mixed with each other and bleed before being absorbed by the recording medium, resulting in deterioration of the image.

On the other hand, in the multi-pass recording method using a line recording head as in the present invention, an image is recorded in a recording area where ink is densely packed with a plurality of reciprocating transports of a recording medium, so that the image is driven per unit time. The amount of ink decreases. Therefore, the bleeding phenomenon is unlikely to occur.

7 and 8 are explanatory views of an example of an 8-pass recording method in which a recording medium is reciprocated eight times to complete image recording as a multi-pass recording method using a line recording head. The number of passes is not limited to 8 and may be 2 or more. 7 and 8 are explanatory views of the recording operation from 1 pass to 18 passes in the 8-pass recording method, and FIG. 7 shows them assuming that the recording head 2 moves relative to the recording medium 4. The positional relationship of is shown. Actually, as shown in FIG. 8, the recording medium 4 moves with respect to the recording head 2.

The 1st to 6th passes are reciprocating transports of the recording medium 4 for recording the tip of the image (conveyance in the directions of arrows X1 and X2). When the unit transport amount of the recording medium 4 is X, the round-trip transport amount at 1 pass and 2 passes is X, and the round-trip transport amount at 3 passes and 4 passes is 2X. The reciprocating transport amount is 3X. At the end of the 6th pass, images of the 6th pass, the 4th pass, and the 2nd pass are recorded in each of the areas A1, A2, and A3 of the recording medium 4. After that, the reciprocating transport amount of the recording medium 4 accompanied by the recording of the image becomes 4X. That is, the reciprocating transport amount at the time of 7 passes and 8 passes is 4X, and when the 8 passes are completed, the image of the region A1 of the recording medium 4 is completed. Although the transport amount in 9 passes is 5X, the transport amount C of the transport amount (also referred to as “empty transport”) without recording the image in the area A1 is included, so that the transport amount of the recording medium 4 accompanied by the image recording is included. Is 4X. The amount of transportation in 10 passes is 4X. After the 11th pass, the regions A1, A2, A3 ... Of the recording medium 4 complete the image by repeating the operation in the same manner as the 9th pass and the 10th pass.

In a single-pass recording method using a line recording head, in order to obtain a multi-pass effect by recording pixels on a recording line along the transport direction of a recording medium using different nozzles, it is necessary to eject ink of the same color. It is necessary to have a plurality of nozzle rows. In a multi-pass recording method as in this example, by arranging at least one row of nozzles for ejecting ink of the same color, a high-quality image can be recorded by the multi-pass effect. That is, it is possible to achieve high image quality of the recorded image by using a line recording head having an inexpensive configuration.

In the present embodiment, as shown in FIGS. 9 and 10, the amount of the recording medium conveyed is changed according to the recording duty of the image. The recording duty corresponds to the amount of ink applied per unit area of the recording medium and can be obtained from the recorded data of the image. 9 and 10 are explanatory views of the recording operation from the N + 1th pass to the N + 18th pass in the 8-pass recording method in which the recording medium is reciprocated eight times to complete the image recording, as in the case of FIGS. 7 and 8. Is. The number of passes is not limited to 8 and may be 2 or more. FIG. 9 shows the positional relationship between the recording heads 2 as if they were moving relative to the recording medium 4. Actually, as shown in FIG. 10, the recording medium 4 moves with respect to the recording head 2.

The area A10 of the recording medium 4 is, for example, a recording area having a high recording duty such that the amount of ink applied per unit area is a predetermined amount or more and the recording duty is 150%. The transport amount of the medium 4 is 0.5X. That is, at the time of N + 1 pass and N + 2 pass, the same operation as that of the 9th pass and the 10th pass in FIGS. 7 and 8 is repeated as usual. At the time of N + 3 pass, the transport amount is changed to 4.5X (= 3.5X + C) and the image of the first pass is recorded in the area A10, and at the time of N + 4 pass, the transport amount is changed to 3.5X. The image of the second pass is recorded in the area A10. At the time of N + 5 passes, the transport amount is changed to 4X (= 3X + C) and the image of the third pass is recorded in the area A10, and at the time of N + 6 passes, the transport amount is changed to 3X and the fourth pass is in the area A10. Record the image of. At the time of N + 7 pass, the transport amount is changed to 3.5X (= 2.5X + C) and the image of the 5th pass is recorded in the area A10, and at the time of N + 8 pass, the transport amount is changed to 2.5X. The image of the sixth pass is recorded in the area A10. At the time of N + 9 pass, the transport amount is changed to 3.5X (= 2.5X + C) and the image of the 7th pass is recorded in the area A10, and at the time of N + 10 pass, the transport amount is changed to 2.5X. The image of the 8th pass is recorded in the area A10.

After that, the regions in which the amount of ink applied per unit region is less than a predetermined amount are sequentially recorded. That is, in the N + 11 pass to the N + 16 pass, the transfer amount is 3X (= 2.5X + 0.5C), 2.5X, 3.5X (= 3X + 0.5C), 3X, 4X (= 3.5X + 0.5C), 3. Switch to 5X and record images sequentially. In the N + 17 and N + 18 passes, the transport amount is set to 4.5X (= 4X + 0.5C) and 4X, and the transport amount of the recording medium 4 accompanied by image recording is returned to the normal 4X. As described above, when the region A10 having a high recording duty exists, the reciprocating transport amount of the recording medium 4 is gradually shortened from the normal transport amount, and the region A10 is empty-conveyed (0.5C) in the N + 11 pass. After that, it gradually becomes longer and returns to the normal transport amount.

As the recording duty, for example, at a recording resolution of 600 dpi, a state in which 600 dots of ink are implanted on a recording medium per inch is defined as a recording duty of 100%. Then, the degree of the recording duty in the predetermined area, for example, the degree of the recording duty in the recording area of 128 dots × 128 dots is determined, and the amount of the recording medium conveyed is changed according to the determination result. The degree of recording duty can be determined for each predetermined area, and when the duty of one area exceeds a predetermined threshold value, the amount of the recording medium conveyed can be changed. In addition, the recording duty for each of a plurality of areas is averaged, the recording duty for a plurality of areas is averaged except for a part (maximum and minimum recording duty), or a combination thereof is used to average the recording duty. The value may be compared with a predetermined threshold.

The recording duty can be determined by counting the number of ink droplets injected into a predetermined area based on the recorded data. In this example, the number of ink droplets of all colors that are ejected into a predetermined area is counted. However, the number of ink droplets injected into a predetermined area may be counted in units of ink colors, or may be counted in units of a plurality of ink colors of two or more colors, or a combination thereof. The timing of such counting is, for example, before the start of transporting the recording medium, when the transport direction of the recording medium is reversed, before recording the image, or between recording on the previous recording medium and recording on the next recording medium. (Also referred to as "between pages").

Although the amount of ink droplets ejected per unit time is reduced by multipath recording, a cockling phenomenon in which the recording medium undulates may occur in an area where the recording duty is high. The wavy portion caused by the cockling phenomenon may come into contact with the recording head, resulting in deterioration of the quality of the recorded image and damage to the recording head. It takes some time from the ink droplets being injected into the recording medium until the recording medium is wavy due to the cockling phenomenon. Therefore, for an area with a high recording duty where a cockling phenomenon is likely to occur, it is effective to complete a recorded image for that area in a short time and shorten the period facing the recording head.

In the present embodiment, the reciprocating transfer amount of the recording medium 4 from the recording of the first pass (N + 3 passes) to the recording of the eighth pass (N + 10 passes) for the area A10 having a high recording duty is shortened. That is, when recording with respect to the area A10, the switching interval between the forward transport and the return transport of the recording medium is shortened. Further, in this example, the transport amount of the recording medium 4 is shortened from the pass (N + 2 pass) before the recording (N + 3 pass) of the first pass.

By shortening the time required for recording an image with respect to the area A10 in this way, it is possible to end the recording of the image with respect to the area A10 before the area A10 may come into contact with the recording head 2 due to the cockling phenomenon. As a result, even if the recording medium is deformed due to the cockling phenomenon, contact between the recording medium and the recording head can be avoided, and deterioration of the recorded image and damage to the recording head can be suppressed. Further, when there is an area having a high image duty, the amount of the recording medium conveyed to the area may be shortened from the start of recording the image. In this case, although the throughput is reduced, the same effect can be obtained. Further, by shifting the head holder 5 in the arrow Y direction while the transport direction of the recording medium is reversed, pixels on the recording line along the transport direction of the recording medium are recorded by using a plurality of different nozzles, and the nozzles are used. It is possible to suppress the influence of variations in ink ejection characteristics for each.

(Second Embodiment)
11 and 12 are explanatory views of a recording method according to a second embodiment of the present invention, and images are recorded by an 8-pass recording method as in the above-described embodiment. In this example, the region A20 having a high recording duty has a higher recording duty than the region A10 in the first embodiment, and the amount of the recording medium conveyed is changed at the time of recording in the region A20. The recording duty of region A20 is, for example, 250%.

With respect to the area A20, the conveyed amount of the recording medium 4 is 0.25X. That is, at the time of N + 1 pass and N + 2 pass, the same operation as that of the 9th pass and the 10th pass in FIGS. 7 and 8 is repeated as usual. At the time of N + 3 pass, the transport amount is changed to 3.25X (= 2.25X + C) and the image of the first pass is recorded in the area A20, and at the time of N + 4 pass, the transport amount is changed to 3.25X. The image of the second pass is recorded in the area A20. At the time of N + 5 pass, the transport amount is changed to 3.5X (= 2.5X + C) and the image of the third pass is recorded in the area A20, and at the time of N + 6 pass, the transport amount is changed to 2.5X. The image of the fourth pass is recorded in the area A20. At the time of N + 7 pass, the transport amount is changed to 2.75X (= 1.75X + C) and the image of the fifth pass is recorded in the area A20, and at the time of N + 8 pass, the transport amount is changed to 1.75X. The image of the sixth pass is recorded in the area A20. At the time of N + 9 pass, the transport amount is changed to 2X (= X + C) and the image of the 7th pass is recorded in the area A20, and at the time of N + 10 pass, the transport amount is changed to 5X and the 8th pass is in the area A20. Record the image of.

After that, in the N + 11 pass to N + 16 pass, the transfer amount is 2X (= 1.75X + 0.25C), 1.75X, 2.75X (= 2.5X + 0.25C), 2.5X, 3.5X (= 3.25X + 0). .25C) Switch to 3.25X and record images sequentially. In the N + 17 and N + 18 passes, the transport amount is set to 4.25X (= 4X + 0.25C) and 4X, and the transport amount of the recording medium 4 accompanied by image recording is returned to the normal 4X. As described above, when the region A20 having a high recording duty exists, the reciprocating transport amount of the recording medium 4 is gradually shortened from the normal transport amount, and the region A20 is empty-conveyed (0.25C) in the N + 11 pass. After that, it gradually becomes longer and returns to the normal transport amount.

The higher the recording duty as in region A20, the faster the deformation of the recording medium due to the cockling phenomenon occurs. By shortening the transport amount of the recording medium as in the present embodiment, the recorded image for the area A20 having a high recording duty where the cockling phenomenon is likely to occur can be completed in a shorter time, and the period facing the recording head can be set. Can be shorter. As a result, deterioration of the recorded image and damage to the recording head due to contact between the recording medium and the recording head can be suppressed more reliably. FIG. 11B is an explanatory diagram of the relationship between the recording duty and the conveyed amount of the recording medium in the 8-pass recording method. As described above, the transport amount at the time of recording in the area where the recording duty is less than 100% is X, and as in the first embodiment, when recording the area A10 where the recording duty is 100% or more and less than 200%. The transport amount is 0.5X. Further, as in the second embodiment, the transport amount at the time of recording in the area A20 having a recording duty of 200% or more and 300 or less is 0.25X. The relationship between the recording duty and the transport amount differs depending on the number of passes of the multi-pass recording method such as 4-pass or 6-pass.

(Third Embodiment)
13 and 14 are explanatory views of the recording method according to the third embodiment of the present invention, and images are recorded by the 8-pass recording method as in the above-described embodiment. In this example, the region A20 having a high recording duty has a recording duty of 250% as in the second embodiment, and the unit transfer amount of the recording medium is changed from X to 0.5X before recording in the region A20. do.

FIG. 9 is an explanatory diagram for shortening the transport amount of the recording medium from the front side approaching the area having a high image duty with respect to the first embodiment. Similar to the first embodiment, the eight-pass recording method is used, and the area having a high image duty is the same 250% duty as in the first embodiment, and the feed amount is changed from X to 0.5X from the front of the image.

Specifically, at the time of N + 1 pass and N + 2 pass, the same operation as that of the 9th pass and the 10th pass in FIGS. 7 and 8 is repeated as usual. Change the transport amount to 4.5X (= 3.5X + C) for N + 3 passes, change the transport amount to 3.5X for N + 4 passes, change the transport amount to 4X (= 3X + C) for N + 5 passes, and change the transport amount to 4X (= 3X + C) for N + 6 passes. Change the transport amount to 3X. At the time of N + 7 pass, the transport amount is changed to 3.5X (= 2.5X + C), and at the time of N + 8 pass, the transport amount is changed to 2.5X. At the time of N + 9 pass, the transport amount is changed to 3X (= 2X + C) and the image of the first pass is recorded in the area A20, and at the time of N + 10 pass, the transport amount is changed to 2X and the image of the second pass is recorded in the area A20. do. At the time of N + 11 pass, the transport amount is changed to 2.5X (= 2X + 0.5C) and the image of the third pass is recorded in the area A20, and at the time of N + 12 pass, the transport amount is changed to 2X and the fourth pass is in the area A20. Record the image of. .. At the time of N + 13 pass, the image of the fifth pass is recorded in the area A20 with the transport amount of 2.5X (= 2X + 0.5C), and at the time of N + 12 pass, the image of the sixth pass is recorded in the area A20 with the transport amount of 2X. Similarly, at the time of N + 15 pass, the image of the 7th pass is recorded in the area A20 with the transport amount of 2.5X (= 2X + 0.5C), and at the time of N + 16 pass, the image of the 8th pass is recorded in the area A20 with the transport amount of 2X. Record. After that, the transport amount is changed to 3X (= 2.5X + 0.5C) at the time of N + 17 pass, and the transport amount is changed to 2.5X at the time of N + 18 pass.

In this way, the transport amount (excluding empty transport) of the recording medium accompanied by image recording is switched from 4X to 3.5X (N + 3, N + 4 passes), and then 3X (N + 5, N + 6 passes), 2.5X (N + 7). , N + 8 passes), 2X (N + 9 to N + 16 passes). Then, after the recording of the area A20 is completed, the transport amount (excluding the empty transport) of the recording medium accompanied by the image recording is 2.5X (N + 17, N + 18 passes), 3X, 3 as in the first embodiment. After switching to .5X and 4X in sequence, it returns to the steady transport amount of 4X.

(Fourth Embodiment)
FIG. 15A is an explanatory diagram of an embodiment in which the transport amount (excluding empty transport) of a recording medium accompanied by image recording is changed according to the environmental temperature and humidity. Areas with 50% recording duty, 150% area A10 as in the first embodiment, and 250% area as in the second embodiment under temperature and humidity (20 ° C./50%) environments. The recorded transport volumes of A20 are X, 0.5X, and 0.25X. Further, in an environment of temperature and humidity (10 ° C./20%), the transport amount at the time of recording in the area where the recording duty is 50%, the area A10 where the recording duty is 150%, and the area A20 where the recording duty is 250% is 1.2X, 0. Change to .6X and 0.3X. Further, in an environment of temperature and humidity (30 ° C./80%), the transport amount at the time of recording in the area where the recording duty is 50%, the area A10 where the recording duty is 150%, and the area A20 where the recording duty is 250% is 0.8X, 0. Change to .4X and 0.2X.

In a high temperature environment and a high humidity environment, the cockling phenomenon of the recording medium occurs more prominently, so that the deformation of the area of the recording medium having a high recording duty occurs in a shorter time. Therefore, in an environment where the temperature and humidity are high, it is effective to shorten the transport amount at the time of recording with respect to the area of the recording medium having a high recording duty. On the contrary, in an environment where the temperature and humidity are low, the amount of the recording medium transported is increased. As described above, the coefficient relating the reference transport amount X and the transport amount at the time of recording in the area of the recording medium having a high recording duty is decreased as the temperature and humidity are higher, and increased as the temperature and humidity are lower. Such a coefficient is not limited to the value shown in FIG. 15A because the optimum value differs depending on the number of passes of the recording method.

(Fifth Embodiment)
FIG. 15B is an explanatory diagram of an embodiment in which the transport amount (excluding empty transport) of a recording medium accompanied by image recording is changed according to the type and thickness of the recording medium. When the recording medium is thin coated paper, the area having a recording duty of 50%, the area A10 having a recording duty of 150% as in the first embodiment, and the area A20 having a recording duty of 250% as in the second embodiment during recording. The amounts are X, 0.5X, and 0.25X. Further, when the recording medium is thick coated paper, the transport amount at the time of recording in the area where the recording duty is 50%, the area A10 where the recording duty is 150%, and the area A20 where the recording duty is 250% is 1.2X, 0.6X, and Change to 0.3X. When the recording medium is plain paper, the amount of transport during recording in the area having a recording duty of 50%, the area A10 having a recording duty of 150%, and the area A20 having a recording duty of 250% is 0.8X, 0.4X, and 0. Change to .2X.

When the recording medium is the same type of coated paper, the thinner it is, the more prominent the cockling phenomenon occurs, and the deformation of the area of the recording medium having a high recording duty occurs in a shorter time. Therefore, it is effective that the thinner the recording medium, the shorter the transport amount at the time of recording with respect to the area of the recording medium having a high recording duty. The reason why the cockling phenomenon occurs more remarkably as the recording medium is thinner is that the amount of water in the ink per unit volume of the recording medium increases and deformation is likely to occur. In addition, the cockling phenomenon occurs more prominently in plain paper than in coated paper, and deformation of the area of plain paper having a high recording duty occurs in a shorter time. Therefore, it is effective to reduce the amount of paper transported during recording with respect to the area of plain paper having a high recording duty. Since plain paper has lower rigidity than coated paper, it is more deformed by the cockling phenomenon. Further, such a difference in rigidity is also due in part to the fact that the coated paper has an ink receiving layer and the plain paper does not have an ink receiving layer. Further, the coefficient relating the reference transport amount X and the transport amount at the time of recording in the area of the recording medium having a high recording duty is changed according to the type and thickness of the recording medium. Such a coefficient is not limited to the value shown in FIG. 15B because the optimum value differs depending on the number of passes of the recording method.

1 Inkjet recording device 2 Recording head 4 Recording medium

Claims (12)

An inkjet recording apparatus for recording an image on the recording medium in a plurality of times by reciprocating the recording medium a plurality of times through a position facing a recording head capable of ejecting ink.
The recording for recording an image in a recording area of the recording medium in which the amount of ink applied per unit area is a predetermined amount or more according to the amount of ink applied per unit area of the recording medium. The reciprocating transfer amount of the medium is shorter than the reciprocating transfer amount when the image is recorded in the recording area of the recording medium in which the amount of ink applied per unit area is less than a predetermined amount in a plurality of times. An inkjet recording apparatus, further comprising a changing means for changing the reciprocating transport amount of the recording medium. The changing means transfers the reciprocating transfer amount for recording an image in the recording area of the recording medium in which the amount of ink applied per unit area is a predetermined amount or more in a plurality of times, and the image is transferred to the recording area. The inkjet recording apparatus according to claim 1 , wherein the time is shortened before recording or when an image is recorded in the recording area. The changing means transfers the reciprocating transfer amount for recording an image in the recording area of the recording medium in which the amount of ink applied per unit area is a predetermined amount or more in a plurality of times, and the image is transferred to the recording area. The inkjet recording apparatus according to claim 1 or 2 , wherein the image is gradually shortened before recording or when an image is recorded in the recording area. The changing means transfers the reciprocating transfer amount for recording an image in the recording area of the recording medium in which the amount of ink applied per unit area is a predetermined amount or more in a plurality of times, and the image is transferred to the recording area. The inkjet recording apparatus according to any one of claims 1 to 3 , wherein the image is gradually shortened before recording or when an image is recorded in the recording area, and then gradually lengthened. When at least one of the environmental temperature and humidity is equal to or higher than a predetermined value , the changing means is applied to the recording area of the recording medium more than once than when at least one of the environmental temperature and humidity is lower than the predetermined value. divided into an ink jet recording apparatus according to the conveyance amount of the reciprocating for recording claim 1, wherein the Shorten to any one of the 4 images. The changing means, the conveyance amount of the reciprocating it Shorten for recording an image by a plurality of times in the recording area of the deformable second recording medium by the application of ink than the first recording medium The inkjet recording apparatus according to any one of claims 1 to 5. The changing means, in response to said type of recording medium, according to claim 6, wherein the racemase Rukoto different conveyance amount of the reciprocating for recording an image by a plurality of times in the recording area of the recording medium The inkjet recording apparatus according to the above. 7. The recording medium of plain paper is characterized in that the reciprocating transport amount for recording an image in a recording area of the recording medium in a plurality of times is shorter than that of the recording medium of coated paper. The inkjet recording apparatus according to the above. When the thickness of the recording medium is greater than or equal to the predetermined thickness, the changing means records an image in the recording area of the recording medium in a plurality of times than when the thickness is less than the predetermined thickness. an ink jet recording apparatus according to the conveyance amount of the reciprocating to claim 6, wherein the Shorten for. The changing means means that the recording medium that does not include the ink receiving layer has the reciprocating transport amount for recording an image in the recording area of the recording medium in a plurality of times than the recording medium that includes the ink receiving layer. There inkjet recording apparatus according to claim 6, characterized in that Shorten. The ink-jet recording apparatus according to any one of 0 claims 1 1, further comprising a moving means for moving the recording head in a direction intersecting the transport direction of the recording medium. An inkjet recording method in which an image is recorded on the recording medium in a plurality of times by reciprocating the recording medium a plurality of times through a position facing a recording head capable of ejecting ink.
The reciprocating transfer amount of the recording medium for recording an image in the recording area of the recording medium in which the amount of ink applied per unit area is equal to or larger than a predetermined amount is the amount of ink applied per unit area. A method of inkjet recording, characterized in that the amount of ink is shorter than the amount of reciprocating transport when an image is recorded in a recording area of the recording medium having a quantity of less than a predetermined amount in a plurality of times.

Images