JP2023119800A - Liquid discharge device, liquid discharge method and program - Google Patents

Abstract

To provide a liquid discharge device, a liquid discharge method and a program which can maintain productivity while preventing deterioration in image quality due to poor drying.SOLUTION: The liquid discharge device comprises: a first head having a nozzle that prints a first image on a recording medium while discharging liquid to the recording medium; a second head, provided closer to a downstream side than the first head in a conveying direction, which has a plurality of nozzles, provided along the conveying direction of the recording medium, which print second images on the recording medium while discharging liquid to the recording medium; and a control part that when performing multi-layer printing for printing the second image on the first image, makes an amount of liquid made to adhere to the recording medium by a nozzle at an upstream side in the conveying direction smaller than an amount of liquid made adhere to the recording medium by a nozzle at a downstream side in the conveying direction, in the second head.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid ejecting apparatus, a liquid ejecting method, and a program.

2. Description of the Related Art In liquid ejection devices such as inkjet printers, a technique has been developed in which a special color (eg, white) is printed as a background color in a first print, and a color image is superimposed thereon in a second print. According to this technique, it is possible to print with enhanced color development regardless of the printing base material. Conversely, in a liquid ejection device, a multi-layer printing technology for use on window films, etc., in which a color image is printed on a transparent base material in the first printing, and a special color (white, etc.) is printed thereon in the second printing. is being developed.

Further, in these techniques, techniques for suppressing image failure caused by the degree of dryness of the image printed by the first printing while maintaining productivity are being considered. For example, Japanese Patent Application Laid-Open No. 2002-100001 discloses that when a color image is formed on a white image, ink is supplied to the downstream side of the head from the upstream side when printing the white image for the purpose of suppressing deterioration of the image quality due to poor drying. Techniques for reducing the ejection amount have been disclosed.

However, in order to dry the image printed by the first printing, the method of providing a waiting time until the second printing and the method of limiting the nozzles used for printing to provide an empty scan area have problems in terms of productivity due to the waiting time. decrease in printing speed, decrease in productivity due to nozzle limitation, and decrease in image quality due to limitation in the number of print scans. Further, in the technique described in Patent Document 1, the image quality is degraded by limiting the number of nozzles used for printing a white image.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid ejecting apparatus, a liquid ejecting method, and a program capable of maintaining productivity while preventing deterioration of image quality due to poor drying. aim.

In order to solve the above-described problems and achieve the object, the present invention provides a first head having nozzles for ejecting liquid onto a recording medium to print a first image, and a print head along the conveying direction of the recording medium. a second head provided downstream of the first head in the transport direction, the second head having a plurality of nozzles for ejecting liquid onto the recording medium to print a second image; When performing multi-layer printing in which the second image is printed on one image, in the second head, the amount of liquid adhered to the recording medium by the nozzles on the upstream side in the conveying direction is changed to a controller that reduces the amount of liquid attached to the recording medium by the nozzles.

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to maintain productivity, preventing the deterioration of the image quality by drying failure.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus to which a liquid ejecting apparatus according to this embodiment is applied. FIG. 2 is a diagram showing an example of control blocks of the image forming apparatus according to this embodiment. FIG. 3 is a diagram showing the outline of the configuration of the heater unit provided in the image forming apparatus according to this embodiment. FIG. 4 is a flowchart showing an example of the flow of ink adhesion amount control processing by the image forming apparatus according to the present embodiment. FIG. 5 is a diagram for explaining an example of multilayer printing in the image forming apparatus according to this embodiment. FIG. 6 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 7 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 8 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 9 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 10 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 11 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. FIG. 12 is a diagram for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment.

Exemplary embodiments of a liquid ejection device, a liquid ejection method, and a program will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus to which a liquid ejecting apparatus according to this embodiment is applied. As shown in FIG. 1, an image forming apparatus 100 according to the present embodiment is assumed to be a wide serial type inkjet recording apparatus.

As shown in FIG. 1, the image forming apparatus 100 includes side plates 21A and 21B on the left and right sides of the apparatus body 100a. The side plates 21A and 21B span a main guide rod 31, which is a guide member. The image forming apparatus 100 also includes a sub sheet metal guide 32 . The main guide rod 31 and the sub sheet metal guide 32 slidably hold the carriage 121 . The carriage 121 moves and scans in the direction of arrow A (carriage main scanning direction) via a timing belt that is rotationally driven by a main scanning motor. Further, the carriage 121 is equipped with an optical sensor 37 that detects an edge (paper edge) of a medium P (an example of a recording medium) such as paper.

The carriage 121 carries yellow (Y), cyan (C), magenta (M), black (K), orange (O), green (G), clear (Cl), etc. according to the mounted ink cartridge 10. It includes liquid ejection heads (an example of heads) 122a, 122b, and 122c that eject ink droplets (an example of liquid) of each color. Hereinafter, the liquid ejection heads 122a, 122b, and 122c are referred to as the liquid ejection heads 122 when not distinguished from each other.

The liquid ejection head 122 arranges a nozzle row composed of a plurality of nozzles in the sub-scanning direction (transporting direction of the medium P). That is, the liquid ejection head 122 has a plurality of nozzles that are provided along the sub-scanning direction and eject ink droplets onto the medium P to print an image. Here, the sub-scanning direction (direction of arrow B) is a direction perpendicular to the carriage main scanning direction (direction of arrow A). The liquid ejection head 122 is mounted so that the direction in which ink droplets are ejected from the nozzles is directed downward.

The liquid ejection heads 122a, 122b, and 122c are installed while being shifted in the sub-scanning direction. That is, the liquid ejection head 122b (an example of the second head) is provided downstream of the liquid ejection head 122c (an example of the first head) in the sub-scanning direction. Further, the liquid ejection head 122a (an example of a second head) is provided downstream of the liquid ejection head 122b (an example of the first head) in the sub-scanning direction. The carriage 121 is equipped with sub-tanks for supplying each color of ink corresponding to the liquid ejection head 122 .

The image forming apparatus 100 includes a cartridge loading section 1 in which ink cartridges 10y, 10c, 10m, and 10k of respective colors are detachably loaded. In the following description, the ink cartridges 10y, 10c, 10m, and 10k are referred to as the ink cartridges 10 when not distinguished. The ink in the ink cartridge 10 is replenished to the sub-tank of the carriage 121 through the supply tube 36 of each color by the supply pump unit. Note that the ink cartridge 10 may include a white ink cartridge.

The image forming apparatus 100 includes a maintenance recovery mechanism 81 in a non-printing area on one side of the carriage 121 in the main scanning direction. The maintenance recovery mechanism 81 maintains and recovers the state of the nozzles of the liquid ejection head 122 . The maintenance and recovery mechanism 81 includes cap members (hereinafter referred to as caps) 82a, 82b, and 82c for capping the nozzle surfaces of the liquid ejection head 122, a wiping unit 83 for wiping the nozzle surfaces, and the like. . In the following description, the caps 82a, 82b, and 82c are referred to as caps 82 when not distinguished. A replaceable waste liquid tank for storing waste liquid generated by the maintenance and recovery operation is provided below the maintenance and recovery mechanism 81 of the liquid ejection head 122 .

FIG. 2 is a diagram showing an example of control blocks of the image forming apparatus according to this embodiment. The image forming apparatus 100 according to the present embodiment has an image processing section 200 and a printer main body 300 as shown in FIG. The image processing unit 200 converts an input image to be printed on the medium P into dot data printable by the printer body 300 and inputs the converted dot data to the printer body 300 .

For example, the image processing unit 200 performs various image processing such as resolution conversion processing, color conversion processing using a color conversion table, halftone processing, and rasterization processing on the input image. After that, the image processing unit 200 converts the input image that has undergone the image processing into dot data of each color, and inputs the dot data to the printer main body 300 .

Specifically, when performing multi-layer printing in which a second image is printed on a first image, the image processing unit 200 (an example of a control unit) controls the medium P in the liquid ejection head 122 that prints the second image. The amount of ink adhered to the medium P by the nozzles on the upstream side in the conveying direction of is smaller than the amount of ink adhered to the medium P by the nozzles on the downstream side in the conveying direction of the medium P. As a result, after the first image such as the background image is printed on the medium P, the number of nozzles used for printing the second image such as the color image increases after the degree of drying of the ink used for printing the first image becomes high. is increased, it is possible to suppress embedding of the dots of the second image in the first image. As a result, it is possible to maintain productivity while preventing deterioration of image quality due to poor drying.

Here, the first image is an image printed by the nozzles of the liquid ejection head (hereinafter referred to as the upstream head) 122 provided on the upstream side in the transport direction of the medium P among the liquid ejection heads 122a, 122b, and 122c. . Here, the second image is the nozzles of a liquid ejection head (hereinafter referred to as a downstream head) provided downstream of the upstream head 122 in the medium P transport direction among the liquid ejection heads 122a, 122b, and 122c. This is an image printed by

Further, when performing multi-layer printing, the image processing unit 200 determines the amount of ink adhered to the medium P by the nozzles on the downstream side in the transport direction of the medium P in the upstream head 122 as may be smaller than the amount of ink adhered to the medium P by the nozzles of .

Further, when performing multi-layer printing, the image processing unit 200 may increase the amount of ink adhered to the medium P by the nozzles of the downstream head 122 from the upstream side toward the downstream side in the transport direction of the medium P. good. Furthermore, when performing multi-layer printing, the image processing unit 200 may reduce the amount of ink adhered to the medium P by the nozzles of the upstream head 122 from the upstream side toward the downstream side in the transport direction of the medium P. good.

In the printer main body 300 to which the dot data is input, the image is printed on the medium P by the controller section 301 controlling and driving various printing units based on the dot data. In the image forming apparatus 100 according to the present embodiment, the number of nozzles to be used in the liquid ejection head 122 and the amount of ink droplet adhesion (ink adhesion amount) in each scan are determined based on the dot data, and the determined ink adhesion amount and the like are determined. The controller unit 301 changes the control of each unit according to various conditions.

In this embodiment, the printer main body 300 includes a controller section 301, an I/F 302, a paper feed unit 303, a transport unit 304, a paper discharge unit 305, a heater unit 306, an ink supply unit 307, a carriage 121, a liquid ejection head 122, and the like. have

An I/F 302 inputs an input image from the image processing unit 200 to the printer main body 300 . The paper feed unit 303 feeds the medium P into the image forming apparatus 100 . The transport unit 304 transports the medium P fed into the image forming apparatus 100 . The paper ejection unit 305 ejects the medium P on which the input image is printed. The heater unit 306 dries the ink droplets adhering to the medium P. The ink supply unit 307 supplies ink from the ink cartridge 10 to the liquid ejection head 122 .

The controller unit 301 has a CPU (Central Processing Unit) 301a and a memory 301b. The memory 301b has a ROM (Read Only Memory) 301c and a RAM (Random Access Memory) 301d. The ROM 301c stores various programs. The RAM 301d is used as a work area when various programs are executed by the CPU 301a.

The CPU 301a controls the operation of the image forming apparatus 100 as a whole. Specifically, the CPU 301a is an example of a processor that uses the RAM 301d as a work area and executes various programs stored in the memory 301b.

FIG. 3 is a diagram showing the outline of the configuration of the heater unit provided in the image forming apparatus according to this embodiment. In the example shown in FIG. 3, two liquid ejection heads 122a and 122b are shown as the liquid ejection head 122 for the sake of simplicity, and description of the liquid ejection head 122c is omitted.

As shown in FIG. 3, the heater 120 included in the heater unit 306 includes a preheater 120a, a print heater 120b, a print heater 120c, a postheater 120d, and a drying heater 120e. Each heater 120 is provided with a temperature sensor such as a thermistor for temperature control.

The preheater 120a is a device that preheats the medium P to a temperature suitable for forming a liquid application surface. For example, preheater 120a (upper margin +2° C., lower margin 0° C.) is an aluminum foil cord heater. The preheater 120 a is attached to the rear surface of the transport guide plate 130 . The preheater 120a warms the medium P by warming the transport guide plate 130 itself. The preheated medium P is sent to the image forming section 50 where the liquid ejection head 122 is arranged by the transport rollers 123a and 123b.

In the image forming section 50, while the medium P is kept warm by the print heaters 120b and 120c, liquid such as ink is ejected from the liquid ejection head 122 to form a liquid application surface. The warmed air rises together with the steam, but in order to prevent the upper portion of the image forming apparatus 100 from excessively increasing in temperature due to its retention, the fan 119 promotes air convection.

The print heater 120b and the print heater 120c are devices for keeping the medium P warm when forming the liquid coating surface on the medium P. FIG. For example, print heater 120b and print heater 120c (upper margin +0.5° C., lower margin −0.5° C.) are code heaters embedded in platen 131 made of aluminum. The print heater 306b and the print heater 306c warm the medium P by warming the platen 131 itself.

The post-heater 120d and the drying heater 120e are devices for warming the medium P on which the liquid application surface is formed in order to dry and fix liquid such as ink. For example, post heater 120d (upper margin +2° C., lower margin 0° C.) is an aluminum foil cord heater. The post-heater 120 d is attached to the rear surface of the transport guide plate 132 . The post-heater 120d warms the medium P by warming the transport guide plate 132 itself. Also, for example, the drying heater 120e (upper margin +0.5° C., lower margin −0.5° C.) is an IR heater. The drying heater 120e irradiates the liquid coated surface of the medium P with IR radiation to dry it. The drying heater 120e may be configured to send hot air to the liquid coated surface of the medium P with a fan.

FIG. 4 is a flowchart showing an example of the flow of ink adhesion amount control processing by the image forming apparatus according to the present embodiment. When the printing operation is started (step S401), the image processing unit 200 reads image data of an input image to be printed on the medium P from an external device (step S402). Next, the image processing unit 200 determines whether or not to perform multi-layer printing of the read image data (step S403).

If multi-layer printing of the read image data is not to be performed (step S403: No), the image processing unit 200 converts the image data into dot data of each color (step S404), and inputs the dot data to the printer main body 300 (step S404). step S405). After that, the printer body 300 prints the input image data (step S406).

On the other hand, when multi-layer printing of the read image data is to be performed (step S403: Yes), the image processing unit 200 determines the ink adhesion amount of the ink on the medium P by the nozzles on the downstream side in the conveying direction of the medium P in the upstream head 122. is less than the amount of ink adhered to the medium P by the nozzles on the upstream side in the transport direction of the medium P (step S407). Further, in the downstream head 122, the image processing unit 200 calculates the ink adhesion amount of the ink on the medium P by the nozzles on the downstream side in the transport direction of the medium P, and the ink on the medium P by the nozzles on the upstream side in the transport direction of the medium P. (step S407). After that, the process proceeds to steps S404 to S406 in the same manner as when multi-layer printing of image data is not performed.

FIG. 5 is a diagram for explaining an example of multilayer printing in the image forming apparatus according to this embodiment. For example, in the case of normal printing without multi-layer printing, a color image is printed on the printing substrate (an example of medium P), but in the case of multi-layer printing, a background image (white image) is printed on the printing substrate. image, etc.), and a color image is printed thereon. In this case, the color image is printed before the background image is dried, and there is a possibility that the desired image quality cannot be obtained.

Therefore, in the image forming apparatus 100 according to the present embodiment, the image processing unit 200 determines the amount of ink adhered to the medium P by the nozzles on the upstream side in the conveying direction of the medium P in the downstream head 122, as described above. is reduced from the amount of ink adhered to the medium P by the nozzles on the downstream side in the transport direction of the medium P. As a result, after the first image such as the background image is printed on the medium P, the number of nozzles used for printing the second image such as the color image increases after the degree of drying of the ink used for printing the first image becomes high. is increased, it is possible to suppress embedding of the dots of the second image in the first image. As a result, it is possible to maintain productivity while preventing deterioration of image quality due to poor drying.

6 and 7 are diagrams for explaining an example of the ink adhesion amount control process in the image forming apparatus according to the present embodiment. In FIG. 7, the vertical axis represents the dot diameter of the second image, and the horizontal axis represents the drying time of the first image. As shown in FIGS. 6 and 7, the degree of dryness of the background image (background color) changes the spread of dots of the color image (color ink) printed on the background image. Specifically, when the degree of dryness of the background image is low, the dots of the color image are buried in the background image and the dot diameter becomes small. On the other hand, when the degree of dryness of the background image is high and the background image becomes dry, the dots of the color image are no longer buried in the background image, and the dot diameter increases.

Furthermore, since the degree of embedding of dots in the background image differs for each color of the color image, even if the background image has the same drying time, the dot diameter of each color will not be the same. Therefore, in the present embodiment, the image processing unit 200 calculates the amount of ink adhered to the medium P by the nozzles on the upstream side in the transport direction of the medium P in the downstream head 122 for each color of the color image. It is also possible to change the amount of ink that is reduced from the amount of ink adhered to the medium P by the nozzles on the downstream side in the transport direction (hereinafter referred to as the amount of reduction). For example, when a color image includes black (Bk) dots and cyan (Cy) dots, the image processing unit 200 sets the amount of reduction for hard-to-dry black to be greater than the amount of reduction for cyan.

8 to 12 are diagrams for explaining an example of ink adhesion amount control processing in the image forming apparatus according to the present embodiment. Here, the upstream head 122 will be described as a head that prints a white image, and the downstream head 122 will be described as a head that prints color images (Bk, Cy, Ma, Ye). The color configurations of the upstream head 122 and the downstream head 122 may be reversed. Further, in the following description, among the nozzle regions of the upstream head 122 and the downstream head 122, the region indicated by reference numeral 801 is defined as a usable nozzle region for ejecting ink, and the region indicated by reference numeral 802 is defined as a nozzle region for ink ejection. is defined as a non-use nozzle region that does not eject.

For example, as shown in FIG. 8, when the used nozzle area is not reduced, that is, when the unused nozzle area is not provided and the number of used nozzles is not changed, white image printing and color image printing are continuously performed. Therefore, there is a high possibility that a drying failure will occur because a sufficient drying time cannot be secured for the white image.

On the other hand, as shown in FIG. 9, when the nozzle areas in use are reduced in both the upstream head 122 and the head 122 in the downstream side to increase the drying time, the area of nozzles in use is reduced. Image quality may be degraded as it needs to complete. Further, as shown in FIG. 10, when the number of print scans is maintained while reducing the number of nozzle areas used, the reduced number of nozzle areas requires empty scans, which reduces productivity.

Therefore, in the present embodiment, as shown in FIG. 11, the image processing unit 200 does not delete the active nozzle area, and in the upstream head 122, the amount of ink per scan is increased toward the downstream side in the transport direction of the medium P. The ink adhesion amount is decreased, and the ink adhesion amount is increased toward the downstream in the conveying direction of the medium P in the downstream head 122 . As a result, the number of scans is maintained to prevent image quality from deteriorating, and printing is also advantageous for drying.

Alternatively, in the present embodiment, as shown in FIG. 12 , the image processing section 200 reduces the ink adhesion amount on the upstream side in the transport direction of the medium P in the downstream head 122 . On the other hand, the image processing unit 200 reduces the usable nozzle area of the upstream head 122 when printing a white image that does not greatly affect the image quality. As a result, printing is performed in a manner that is advantageous for drying, and the number of scans is increased in the printed portion of the downstream head 122 where image quality is required, and the amount of ink adhered is changed so as to be advantageous for drying.

As described above, according to the image forming apparatus 100 according to the present embodiment, after the first image such as the background image is printed on the medium P, the drying degree of the ink used for printing the first image increases. Therefore, since the number of nozzles used for printing the second image such as a color image is increased, it is possible to suppress the embedding of the dots of the second image in the first image. As a result, it is possible to maintain productivity while preventing deterioration of image quality due to poor drying.

It should be noted that the program executed by the image forming apparatus 100 according to the present embodiment is preinstalled in a ROM or the like and provided. In addition, the program executed by the image forming apparatus 100 of the present embodiment is a file in an installable format or an executable format and can be stored on a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk). It may be configured to be provided by being recorded on a computer-readable recording medium such as.

Further, the program executed by image forming apparatus 100 of the present embodiment may be stored in a computer connected to a network such as the Internet, and provided by being downloaded via the network. Also, the program executed by the image forming apparatus 100 of the present embodiment may be provided or distributed via a network such as the Internet.

The program executed by the image forming apparatus 100 of the present embodiment has a module configuration including the above-described units (the image processing unit 200). By reading out and executing the program, each of the above sections is loaded onto the main storage device, and the image processing section 200 is generated on the main storage device.

In the above embodiment, an example in which the image forming apparatus 100 of the present invention is applied to a multifunction machine having at least two functions out of a copy function, a printer function, a scanner function, and a facsimile function will be described. It can be applied to any image forming apparatus such as a machine, a printer, a scanner, a facsimile, and the like.

REFERENCE SIGNS LIST 100 image forming apparatus 121 carriage 122 liquid ejection head 200 image processing section 300 printer main body

JP 2021-66064 A

Claims (6)

a first head having nozzles for printing a first image by ejecting liquid onto a recording medium;
a plurality of nozzles that are provided along the conveying direction of the recording medium and eject liquid onto the recording medium to print a second image, and are provided downstream of the first head in the conveying direction; a second head formed by
In the case of performing multi-layer printing in which the second image is printed on the first image, in the second head, the amount of liquid adhered to the recording medium by the nozzles on the upstream side in the conveying direction is determined as a control unit that reduces the amount of liquid attached to the recording medium by the nozzle on the side;
A liquid ejection device comprising: the first head has a plurality of nozzles that are provided along the transport direction and eject liquid onto the recording medium;
Further, when the multi-layer printing is performed, the controller controls the amount of liquid adhered to the recording medium by the nozzles on the downstream side in the transport direction in the first head. 2. The liquid ejecting apparatus according to claim 1, wherein the amount of liquid adhered to the recording medium is reduced. 3. When performing the multi-layer printing, the control unit increases the amount of liquid adhered to the recording medium by the nozzles of the second head from the upstream side toward the downstream side in the transport direction. 3. The liquid ejecting apparatus according to . 3. The method according to claim 2, wherein, when performing the multi-layer printing, the control unit reduces the amount of liquid adhered to the recording medium by the nozzles of the first head from the upstream side toward the downstream side in the transport direction. liquid ejection device. A liquid ejection apparatus comprising: a first head having nozzles; and a second head having a plurality of nozzles provided along a conveying direction of a recording medium and provided downstream of the first head in the conveying direction. A liquid ejection method performed in
a step of ejecting liquid from nozzles of the first head onto the recording medium to print a first image;
a step of ejecting liquid from nozzles of the second head onto the recording medium to print a second image;
In the case of performing multi-layer printing in which the second image is printed on the first image, in the second head, the amount of liquid adhered to the recording medium by the nozzles on the upstream side in the conveying direction is determined as a step of reducing the amount of liquid adhered to the recording medium by the side nozzle;
A liquid dispensing method comprising: a first head having nozzles for printing a first image by ejecting liquid onto a recording medium; and a second head provided along a conveying direction of the recording medium and ejecting liquid onto the recording medium to print a second image. a computer for controlling a liquid ejection device having a plurality of nozzles for printing and a second head provided downstream of the first head in the transport direction;
In the case of performing multi-layer printing in which the second image is printed on the first image, in the second head, the amount of liquid adhered to the recording medium by the nozzles on the upstream side in the conveying direction is determined as a control unit that reduces the amount of liquid attached to the recording medium by the nozzle on the side;
A program to function as

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