Liquid ejection apparatus, image forming apparatus, liquid ejection method, and program

Abstract

This process equalizes the image quality in the nozzle overlap area at the head ends of adjacent liquid dispensing heads. [Solution] The present invention provides a liquid dispensing device having a first, second head or head tip that arranges a nozzle row consisting of a plurality of nozzles and selectively discharges droplets from the nozzles, wherein the first, second head or head tip is installed with a nozzle overlap region at the end of the nozzle row in the row direction, and the mask pattern of the nozzle overlap region is composed of data in a direction parallel to the row direction of the nozzle row, consisting of either pixel data from the first head or head tip and pixel data from the second head or head tip of the first, second head or head tip, and when the end nozzle of the first head or head tip discharges a droplet, the nozzle adjacent to the first head of the first head or head tip adjacent to the end nozzle discharges a droplet.

Description

Technical Field

[0001] The present invention relates to a liquid ejection device, an image forming device, a liquid ejection method, and a program.

Background Art

[0002] Conventionally, a technique related to image processing in a nozzle overlap region at an end of adjacent liquid ejection heads has been considered and is already known.

[0003] Patent Document 1 discloses a technique for suppressing image quality degradation in a nozzle overlap region of a liquid ejection head by applying a mask to the nozzle overlap region and forming an image by mixing printing dots with two liquid ejection heads. Patent Documents 2-4 disclose techniques for correcting image data or controlling the ejection amount of an aggregation liquid for the purpose of suppressing white streaks and black streaks generated at joints when short heads are connected to form a long head.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when printing dots are distributed in the nozzle overlap region of two liquid ejection heads as in the prior art, the driving frequency per nozzle decreases compared to the normal nozzle region outside the nozzle overlap region. Generally, since the ejection droplet amount of a liquid ejection head often varies according to the driving frequency, the dot size of the printing dots changes in the masked nozzle overlap region. There is a problem that a portion where the dot size of the printing dots changes in the nozzle overlap region is visually recognized as density unevenness or streaks.

[0005] Furthermore, in the nozzle overlap region where masking is applied, it is ideal for the printed dots ejected from the two liquid ejection heads to land in ideal positions. However, if the landing position of the printed dots from one liquid ejection head is shifted relative to the other due to misalignment or differences in droplet velocity between the two liquid ejection heads, it becomes impossible to achieve the same density as the normal nozzle region. This area where the same density as the normal nozzle region cannot be achieved also presents as density unevenness or streaks, which is a problem. In addition, the technology described in Patent Documents 2-4 has the problem that feedback processing is required for image data correction. Furthermore, in the technology described in Patent Documents 3 and 4, since the number of nozzles in the connecting section is the same as in the normal section, there is no flexibility in the masking process of the connecting section. Moreover, the head ends are prone to ink clogging, resulting in the appearance of missing nozzles and significant crosstalk, but even if these problems occur, the nozzles at the head ends must be used, resulting in insufficient suppression of streaks.

[0006] The present invention has been made in view of the above, and aims to equalize the image quality of the nozzle overlap region at the head ends of adjacent liquid discharge heads. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the present invention provides a liquid dispensing device having a first, second head or head tip that arranges a nozzle row consisting of a plurality of nozzles and selectively discharges droplets from the nozzles, wherein the first, second head or head tip is installed with a nozzle overlap region at the end of the nozzle row in the row direction, wherein the mask pattern of the nozzle overlap region is composed of data in a direction parallel to the row direction of the nozzle row, consisting of either pixel data from the first head or head tip or pixel data from the second head or head tip, and when the end nozzle of the first head or head tip discharges a droplet, the nozzle adjacent to the first head of the first head or head tip adjacent to the end nozzle discharges a droplet. [Effects of the Invention]

[0008] According to the present invention, the image quality of the nozzle overlap region at the head ends of adjacent liquid discharge heads can be made uniform. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the inside of an image forming apparatus according to the first embodiment. [Figure 2] Figure 2 shows a schematic diagram of the configuration of an image forming apparatus. [Figure 3] Figure 3 is a block diagram showing an example of the hardware configuration of an image forming apparatus. [Figure 4] Figure 4 is a block diagram showing an example of the functional configuration of the control unit. [Figure 5] Figure 5 shows an example of a conventional mask pattern when the end nozzles of two heads aligned in the X direction are arranged in an overlapping pattern. [Figure 6] Figure 6 shows the characteristics of the conventional discharge droplet volume drive frequency. [Figure 7] Figure 7 shows the characteristics of the drive frequency and a conventional mask pattern. [Figure 8-1] Figure 8-1 shows the Y-shift and a conventional mask pattern. [Figure 8-2] Figure 8-2 shows the Y-shift and the conventional mask pattern. [Figure 9-1] Figure 9-1 shows an example of a mask pattern according to the first embodiment. [Figure 9-2] Figure 9-2 shows an example of a mask pattern according to the first embodiment. [Figure 10] Figure 10 shows an example of a mask pattern according to the second embodiment. [Figure 11] Figure 11 is a graph illustrating an example of nozzle utilization in the nozzle overlap region. [Figure 12]FIG. 12 is a diagram showing an example of a mask pattern according to the third embodiment. [Figure 13] FIG. 13 is a diagram showing another example of a mask pattern. [Figure 14] FIG. 14 is a diagram showing an example of a mask pattern according to the fourth embodiment. [Figure 15] FIG. 15 is a diagram exemplarily showing the state of ejected droplets in an end region of a liquid ejection head. [Figure 16] FIG. 16 is a diagram showing another example of a mask pattern. [Figure 17] FIG. 17 is a diagram showing an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the fifth embodiment. [Figure 18] FIG. 18 is a diagram showing an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the sixth embodiment. [Figure 19] FIG. 19 is a diagram showing an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the seventh embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of a liquid ejection device, an image forming device, a liquid ejection method, and a program will be described in detail with reference to the accompanying drawings.

[0011] Hereinafter, as an example of a device that ejects a liquid to which the present invention is applied, an image forming device which is an aspect of a device that ejects a liquid will be described as an example, but the present invention is not limited thereto.

[0012] (First Embodiment) FIG. 1 is a perspective view showing the interior of an image forming apparatus 100 according to the first embodiment in a perspective manner. FIG. 2 is a diagram showing an outline of the configuration of the image forming apparatus 100. As shown in FIGS. 1 and 2, the image forming apparatus 100 according to the present embodiment is a wide-width serial type inkjet recording apparatus.

[0013] In this embodiment, the liquid ejection device of the present invention is described using an example of application to a wide-format serial inkjet printer. However, it can be applied to any image forming apparatus such as a multifunction printer, copier, printer, scanner, or facsimile machine that has at least two functions from among the copying, printing, scanning, and facsimile functions.

[0014] As shown in Figures 1 and 2, the image forming apparatus 100 is equipped with side plates 21A and 21B on the left and right sides of the apparatus body 100a. The side plates 21A and 21B horizontally support the main guide rod 31, which is a guide member. The image forming apparatus 100 is also equipped with a sub-sheet metal guide 32. The main guide rod 31 and the sub-sheet metal guide 32 slidably hold the carriage 121.

[0015] The carriage 121 moves relative to the medium 40 by moving in the direction of arrow Y (main scanning direction) via a timing belt that is rotationally driven by the main scanning motor 117 (see Figure 3). The movement of the carriage 121 can also be referred to as scanning. The carriage 121 is also equipped with an optical sensor 37 that detects the edge of the medium 40 (paper edge).

[0016] The optical sensor 37 is an example of a reading unit that outputs a reading signal for an image previously formed on the medium 40 by the image forming apparatus 100. The optical sensor 37 can be a device that detects by reflectance density, or a camera that captures the image formed on the medium 40.

[0017] The carriage 121 is equipped with heads 122a, 122b, and 122c (collectively referred to as the "liquid ejection head 122") that eject ink droplets (liquid) of each color, such as yellow (Y), cyan (C), magenta (M), black (K), orange (O), green (G), and clear (Cl), depending on the installed ink cartridge 10.

[0018] The medium 40 moves relative to the liquid discharge head 122 by moving along the sub-scanning direction (direction of arrow X), which is approximately perpendicular to the main scanning direction (Y direction), using a transport roller that is rotationally driven by the sub-scanning motor 118 (see Figure 3). However, the main scanning direction (Y direction) and the sub-scanning direction (X direction) do not necessarily have to be approximately perpendicular; they only need to intersect.

[0019] The print heads 122a, 122b, and 122c have nozzle rows consisting of multiple nozzles (not shown) arranged in the sub-scanning direction (X direction). The print heads 122a, 122b, and 122c are mounted with the ink droplet ejection direction from the nozzles facing downwards (Z direction: see Figure 15). The print heads 122a, 122b, and 122c are installed overlapping in the sub-scanning direction (X direction). The carriage 121 is equipped with sub-tanks to supply ink of each color corresponding to the print heads 122a, 122b, and 122c.

[0020] A "liquid discharge head" is a functional component that discharges or sprays liquid from a nozzle. The discharged liquid can be any liquid that has the viscosity and surface tension to be discharged from the liquid discharge head 122, and is not particularly limited, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, as inkjet inks, surface treatment liquids, components for electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D molding.

[0021] The energy source for discharging liquid from the "liquid discharge head" includes pressure generating means such as piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements).

[0022] Furthermore, the "liquid discharge head" is not limited to any particular pressure generating means. For example, in addition to the piezoelectric actuators mentioned above (which may use multilayer piezoelectric elements), it may also use thermal actuators that use electrothermal conversion elements such as heating resistors, or electrostatic actuators consisting of a diaphragm and a counter electrode.

[0023] The image forming apparatus 100 includes a cartridge loading unit 1 for detachably mounting ink cartridges 10y, 10c, 10m, and 10k of each color (referred to as "ink cartridge 10" when not distinguished).

[0024] The ink in the ink cartridge 10 is supplied to the sub-tanks of the carriage 121 via supply tubes 36 for each color by a supply pump unit. The supply pump unit and supply tubes 36 constitute the supply mechanism. Note that the ink cartridge 10 may also include a white ink cartridge.

[0025] The image forming apparatus 100 is equipped with a maintenance and recovery mechanism 81 in the non-printing area on one side of the carriage 121 in the main scanning direction (Y direction). The maintenance and recovery mechanism 81 maintains and / or restores the state of the nozzle of the liquid ejection head 122.

[0026] The maintenance and recovery mechanism 81 includes cap members 82a, 82b, and 82c (referred to as "cap members 82" when not distinguished) for capping each nozzle surface of the liquid discharge head 122, and a wiping unit 83 for wiping the nozzle surface. A replaceable waste liquid tank for collecting waste liquid generated by the maintenance and recovery operation is provided below the maintenance and recovery mechanism 81 of the liquid discharge head 122.

[0027] A "liquid discharge unit" is a collection of components related to liquid discharge, in which functional parts and mechanisms are integrated with the liquid discharge head 122. For example, a "liquid discharge unit" may include a combination of the liquid discharge head 122 with at least one of the following components: a head tank (sub-tank of the carriage 121), the carriage 121, a supply mechanism, a maintenance and recovery mechanism 81, and a main scanning movement mechanism.

[0028] Here, integration includes, for example, cases where the liquid dispensing head 122 and functional components and mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. Alternatively, the liquid dispensing head 122 and functional components and mechanisms may be configured to be detachable from each other.

[0029] For example, some liquid dispensing units have a liquid dispensing head 122 and a head tank integrated into one unit. Others have a liquid dispensing head 122 and a head tank integrated together by connecting them with tubes or the like. In these liquid dispensing units, a unit including a filter can also be added between the head tank and the liquid dispensing head 122.

[0030] Furthermore, some liquid dispensing units integrate the liquid dispensing head 122 and the carriage 121 into a single unit.

[0031] Furthermore, some liquid discharge units have a liquid discharge head 122 that is movably held by a main guide rod 31, which is a guide member that constitutes part of the main scanning movement mechanism, thereby integrating the liquid discharge head 122 and the main scanning movement mechanism. Others have a liquid discharge head 122, carriage 121, and main scanning movement mechanism integrated into one unit.

[0032] Furthermore, as a liquid discharge unit, a cap member 82, which is part of the maintenance and recovery mechanism 81, is fixed to a carriage 121 to which a liquid discharge head 122 is attached, thereby integrating the liquid discharge head 122, carriage 121, and maintenance and recovery mechanism 81.

[0033] Furthermore, some liquid discharge units have a supply tube 36 connected to a liquid discharge head 122 to which a head tank (a sub-tank of the carriage 121) or flow path components are attached, integrating the liquid discharge head 122 with the supply mechanism. Through this tube, liquid from the liquid storage source is supplied to the liquid discharge head 122.

[0034] The main scanning movement mechanism includes the main guide rod 31, which is a guide member. The supply mechanism also includes the supply tube 36 and the cartridge loading section 1.

[0035] Figure 3 is a block diagram showing an example of the hardware configuration of the image forming apparatus 100. As shown in Figure 3, the image forming apparatus 100 includes a control unit 101, an operation panel 114, an environmental sensor 115, an optical sensor 37, a head driver 116, a main scanning motor 117, a sub-scanning motor 118, a fan 119, a heater 120, a liquid discharge head 122, and a moving mechanism 140.

[0036] As shown in Figure 3, the control unit 101 includes a CPU (Central Processing Unit) 102, ROM (Read Only Memory) 103, RAM (Random Access Memory) 104, non-volatile memory (NVRAM) 105, ASIC (Application Specific Integrated Circuit) 106, I / F 107, print control unit 108, main scanning motor drive unit 109, sub-scanning motor drive unit 110, fan control unit 111, heater control unit 112, and I / O 113. Note that the control unit 101 may include configurations other than those described above. In this embodiment, a device including the control unit 101 and liquid ejection head 122 functions as an example of a liquid ejection device.

[0037] The CPU 102, ROM 103, RAM 104, non-volatile memory 105, ASIC 106, I / F 107, print control unit 108, main scanning motor drive unit 109, sub-scanning motor drive unit 110, fan control unit 111, heater control unit 112, and I / O 113 are connected to each other so as to be able to communicate with one another, for example, via a bus.

[0038] The CPU 102 controls the operation of the entire image forming apparatus 100. Specifically, the CPU 102 implements various functions by executing programs stored in the ROM 103, etc.

[0039] ROM 103 stores programs executed by CPU 102 and other fixed data. RAM 104 temporarily stores image data, etc. Non-volatile memory 105 retains data even when the power supply to the image forming apparatus 100 is cut off. ASIC 106 is a circuit for processing image processing such as various signal processing and sorting, and for processing input and output signals to control the entire apparatus.

[0040] I / F107 is an interface circuit that sends and receives data and signals to and from the host. Specifically, I / F107 receives print data (image data), etc., generated by the printer driver of the host, such as an information processing device, image reading device, or imaging device, via cables, networks, etc. In other words, the generation output of print data to the control unit 101 may be performed by the printer driver on the host side.

[0041] The print control unit 108 is a circuit that generates a drive waveform for driving the liquid ejection head 122 and outputs print data and various related data to the head driver 116 to select and drive a pressure generating means that generates pressure for the liquid ejection head 122 to eject liquid (ink) from its nozzle.

[0042] The main scanning motor drive unit 109 is a circuit for driving the main scanning motor 117. The sub-scanning motor drive unit 110 is a circuit for driving the sub-scanning motor 118. The fan control unit 111 is a circuit for controlling the output of the fan 119 so that air is blown at a predetermined temperature and volume.

[0043] The heater control unit 112 is a circuit for controlling the heater 120 to reach a set temperature. The I / O 113 is a circuit for acquiring information from the environmental sensor 115 and extracting information necessary for controlling each part of the image forming apparatus 100. The I / O 113 also receives detection signals from various sensors other than the environmental sensor 115 (for example, the optical sensor 37).

[0044] The control panel 114 is a device for inputting and displaying various information, such as user-specified resolution. The control panel 114 is connected to the CPU 102, etc., via the bus of the control unit 101, for example, so that they can communicate with each other.

[0045] The environmental sensor 115 is a sensor that detects, for example, ambient temperature and ambient humidity. The environmental sensor 115 is connected to the I / O 113 of the control unit 101.

[0046] The head driver 116 is a circuit for driving the liquid ejection head 122 by selectively applying drive pulses, which constitute a drive waveform provided by the print control unit 108 based on input image data (e.g., dot pattern data), to the pressure generating means of the liquid ejection head 122. The head driver 116 is connected to the print control unit 108 of the control unit 101. The ejection amount is controlled, for example, by controlling the amplitude of the drive waveform input to the pressure generating means of the liquid ejection head 122, but the ejection amount may be controlled by other means.

[0047] The main scanning motor 117 is a device that, when driven, rotates the timing belt and moves the carriage 121 equipped with the liquid discharge head 122 in the main scanning direction (direction of arrow Y). The main scanning motor 117 is connected to the main scanning motor drive unit 109 of the control unit 101.

[0048] The sub-scanning motor 118 is a device that, when driven, operates a transport roller that transports the medium 40, which is the object to be ejected by the liquid (ink) from the liquid ejection head 122, in the sub-scanning direction (X direction). The sub-scanning motor 118 is connected to the sub-scanning motor drive unit 110 of the control unit 101.

[0049] The moving mechanism 140 moves the liquid discharge head 122 and the medium 40 relative to each other. The moving mechanism 140 includes a main guide rod 31, a sub-sheet metal guide 32, a carriage 121, and transport rollers, etc., and constitutes the main scanning moving mechanism.

[0050] The moving mechanism 140 moves the liquid discharge head 122 and the medium 40 relative to each other along the main scanning direction (Y direction) using the main guide rod 31, sub-sheet metal guide 32, and carriage 121, etc. The moving mechanism 140 also moves the liquid discharge head 122 and the medium 40 relative to each other along the sub-scanning direction (X direction) using transport rollers, etc. that transport the medium 40. In this embodiment, the relative movement in the sub-scanning direction (X direction) by the moving mechanism 140 is intermittent movement. Intermittent movement refers to movement that alternates between moving and stopping.

[0051] The fan 119 is a device that, when driven, promotes convection of air inside the image forming apparatus 100, preventing the upper part of the image forming apparatus 100 from overheating due to the accumulation of warmed air. The fan 119 is connected to the fan control unit 111 of the control unit 101.

[0052] Figure 4 is a block diagram showing an example of the functional configuration of the control unit 101. Note that components that overlap with those in Figure 3 are not described.

[0053] As shown in Figure 4, the control unit 101 includes a color plate division data generation unit 211 and an ejection control unit 212. The ejection control unit 212 basically controls the ejection of ink.

[0054] When the image data to be printed is input to the color plate division data generation unit 211, it generates color plate division data for each ink color implemented in the image forming apparatus 100 from the input image data (an example of an input image). For example, when the image forming apparatus 100 performs printing using CMYK inks, the color plate division data generation unit 211 generates color plate division data for each CMYK color from the input image data.

[0055] The ejection control unit 212 generates print dot data by applying a dot data generation mask to the color plate division data for each color generated by the color plate division data generation unit 211. Here, the dot data generation mask is, for example, a mask pattern for creating images by mixing print dots with two liquid ejection heads in the nozzle overlap region at the ends of adjacent heads 122a, 122b, and 122c.

[0056] The control unit 101 implements these functions (color plate division data generation unit 211, ejection control unit 212) by having the CPU 102 execute a predetermined program. The control unit 101 may also implement some or all of these functions by one or more processing circuits.

[0057] "Processing circuit" refers to a processor implemented by an electronic circuit, which is programmed to execute each function by software, as well as devices such as ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and conventional circuit modules designed to execute the functions described above.

[0058] The control unit 101 controls the liquid ejection head 122 and the moving mechanism 140 so as to place ink on the medium 40 while moving the liquid ejection head 122 relative to the medium 40 multiple times. The ink placed on the medium 40 forms dots in the image by fixing to the medium 40. More specifically, one ink droplet formed by the ink ejected from the liquid ejection head 122 lands on the medium 40, dries, and fixes to the medium 40, forming one dot in the image. The image is formed as a collection of multiple dots.

[0059] Here, I will explain the conventional problems.

[0060] Figure 5 shows an example of a conventional mask pattern when the end nozzles of two heads 201a and 201b, which are aligned in the X direction, are arranged in an overlapping pattern. Figure 6 shows the characteristics of the drive frequency for the conventional discharge droplet volume. Figure 7 shows the characteristics of the drive frequency and the conventional mask pattern. Figures 8-1 and 8-2 show the Y shift and the conventional mask pattern. In Figure 5, both head 201a and head 201b have 12 nozzles in the overlapping nozzle overlap region 202, but this number can be more or less.

[0061] The impact dot A shown in Figure 5 represents the appearance of a printed dot when droplets ejected from heads 201a and 201b land in ideal positions on the recording medium 203. The impact dot A includes a normal area A1, a normal area A2, and a mask area A3 corresponding to the nozzle overlap region 202.

[0062] As shown in Figure 5, the normal portion A1 of the impact dot A is formed by droplets ejected from head 201a, and the normal portion A2 is formed by droplets ejected from head 201b.

[0063] As shown in Figure 5, the mask portion A3 of the impact dot A is formed by droplets ejected from the nozzles in the nozzle overlap region 202 of heads 201a and 201b. Here, the length of the mask portion A3 in the X direction is 12 pixels, but the nozzle overlap region 202 can be formed by a total of 24 nozzles, consisting of 12 nozzles from head 201a and 12 nozzles from head 201b, so there are twice as many nozzles as in the normal portions A1 and A2. The mask portion A3 of the impact dot A shown in Figure 5 shows an example of XY uniform masking processing in which the printed dots formed by heads 201a and 201b are arranged alternately in both the X and Y directions. By using this XY uniform masking processing, the mask portion A3 is imaged by mixing the printed dots of the two heads 201a and 201b, thereby suppressing image quality degradation such as density unevenness and streaks caused by variations in the ejection characteristics of heads 201a and 201b, and impact misalignment due to airflow at the ends of the liquid ejection heads.

[0064] Incidentally, as shown in Figure 6, the amount of liquid discharged from a liquid dispensing head generally fluctuates due to differences in the residual vibration of the pressure wave remaining after discharge, depending on the drive frequency of the drive waveform. Figure 6 shows an example where the "droplet amount 1" at drive frequency F decreases to "droplet amount 2" when the drive frequency becomes (1 / 2)F.

[0065] More specifically, as shown in Figure 7(a), when XY uniform masking is performed in the nozzle overlap region 202 of the two heads 201a and 201b to distribute the printed dots, the ejection interval in the masked section A3 for a single head will be different from the ejection interval in the normal sections A1 and A2. As a result, as shown in Figure 7(b), the drive frequency per nozzle in the masked section A3 of the target dot A corresponding to the nozzle overlap region 202 will be reduced to (1 / 2)F compared to the drive frequency F of the normal sections A1 and A2. Therefore, the normal sections A1 and A2 will be formed with "droplet amount 1" and the masked section A3 with "droplet amount 2", resulting in the masked section A3 being thinner than the normal sections A1 and A2, causing white unevenness.

[0066] Furthermore, as shown in Figure 8-1, a misalignment in the Y direction (ΔY) between the two heads 201a and 201b, or a difference in droplet velocity between the two heads 201a and 201b, can cause the landing position of the printed dots on one head to shift relative to the other. This can result in the printed dots on heads 201a and 201b overlapping, making it impossible to achieve the same density in mask section A3 as in normal sections A1 and A2. This also presents a problem as density unevenness or streaks become visible.

[0067] Furthermore, as shown in Figure 8-2, in the conventional mask section A3 configuration, the discharge liquid is discharged from the nozzle adjacent to the nozzle at the outermost end of the heads 201a and 201b, which is the most prone to bending. This configuration makes it more likely for the discharge liquid to curve upon impact and for white streaks to occur. Generally, discharge droplets discharged from the outermost nozzles of the heads 201a and 201b are drawn towards the center of the heads 201a and 201b by the airflow. Therefore, to suppress this effect, it is necessary to suppress the discharge airflow near the outermost end.

[0068] Therefore, in this embodiment, in the nozzle overlap region 300 (see Figure 9-1) at the ends of two adjacent heads, the image quality of the nozzle overlap region 300 at the ends of the heads is made uniform by a mask pattern that reduces the occurrence of density unevenness and streaks caused by differences in the characteristics of the drive frequency of the discharged droplet amount between the heads, or differences in positional misalignment or droplet velocity between the heads.

[0069] Here, Figure 9-1 shows an example of a mask pattern according to the first embodiment. Here, the nozzle overlap region 300 of two heads 122a and 122b will be explained as an example.

[0070] As shown in Figure 9-1, the mask portion A3 of the impact dot A is formed by droplets ejected from the nozzles of the nozzle overlap region 300 of heads 122a and 122b. Here, the length of the mask portion A3 in the X direction is 12 pixels. On the other hand, the nozzle overlap region 300 can be imaged with a total of 24 nozzles, consisting of 12 nozzles from head 122a and 12 nozzles from head 122b, so it has twice as many nozzles as the normal portions A1 and A2. In other words, the nozzle overlap region 300 may have twice the number of nozzles as the normal portions A1 and A2 (an example of a normal region).

[0071] As shown in Figure 9-1, the discharge control unit 212 of the control unit 101 sets the odd-numbered nozzles 1a from the head end to "use" and the even-numbered nozzles 1b from the head end to "not use" in the nozzle row of the nozzle overlap region 300 of the head 122a. Also, the discharge control unit 212 of the control unit 101 sets the odd-numbered nozzles 2a from the head end to "use" and the even-numbered nozzles 2b to "not use" in the nozzle row of the nozzle overlap region 300 of the head 122b. As a result, as shown in Figure 9-1, in the nozzle overlap region 300, the nozzles 1a (use) of head 122a and the nozzles 2b (not use) of head 122b overlap, and the nozzles 1b (not use) of head 122a and the nozzles 2a (use) of head 122b overlap.

[0072] In this way, as shown in Figure 9-1, the ejection control unit 212 of the control unit 101, in the masking process of the nozzle overlap region 300, alternates between printed dots formed by head 122a and printed dots formed by head 122b in the X direction, but in the Y direction, it creates a vertical striped mask pattern in which printed dots formed by the same heads 122a and 122b are continuous. That is, heads 122a and 122b are examples of first and second heads (or head tips) that arrange a nozzle row consisting of multiple nozzles, and these nozzles selectively eject ejection droplets (an example of liquid droplets) such as ink. The heads 122a and 122b (or head tips) are installed with a nozzle overlap region 300 provided at the end of the nozzle row in the row direction (X direction). The ejection control unit 212 then configures the mask pattern of the nozzle overlap region 300 with data in the direction parallel to the direction of the nozzle row (X direction), consisting of either pixel data from head 122a (an example of the first head) or head chip, and pixel data from head 122b (an example of the second head) or head chip. The ejection control unit 212 may also configure the nozzle overlap region 300 such that head 122a or head chip and head 122b or head chip do not overlap in the main scanning direction (Y direction), but overlap in the sub-scanning direction (X direction).

[0073] In the example shown in Figure 9-1(a), the ejection interval in the mask section A3 and the ejection intervals in the normal sections A1 and A2 for a single head are the same, resulting in the same drive frequency for the printed dots in the normal sections A1 and A2 and the mask section A3. Therefore, it is not affected by the characteristics of the drive frequency as shown in Figure 6, and the difference in droplet volume due to the difference in drive frequency characteristics as shown in Figure 7 does not occur, making it possible to match the dot size of the printed dots in the normal sections A1 and A2 and the mask section A3.

[0074] Furthermore, as shown in Figure 9-1(b), even if a positional shift (Y-shift) ΔY occurs in the Y direction between the two heads 122a and 122b, the mask pattern is a vertical stripe pattern that creates a continuous sequence of printed dots formed by the same heads 122a and 122b in the Y direction. Therefore, as shown in Figure 8-1, the printed dots do not overlap. Accordingly, the mask pattern according to this embodiment can suppress the occurrence of image quality degradation such as density unevenness and streaks in the nozzle overlap region 300 between adjacent heads 122a and 122b compared to conventional mask patterns.

[0075] Figure 9-2 shows an example of a mask pattern according to the first embodiment. The masking process for the nozzle overlap region 300 in this embodiment is characterized by arranging printed dots formed by head 122a and printed dots formed by head 122b in the X direction, but consisting only of printed dots formed by the same head in the Y direction. With this method, the dot sizes of the normal areas A1, A2 and the mask area A3 can be matched without being affected by frequency characteristics as shown in Figures 6 and 7. Furthermore, even if a Y shift occurs, the printed dots will not overlap as shown in Figure 8-1.

[0076] Furthermore, when a nozzle at the head end of heads 122a and 122b (an example of an end nozzle) discharges a droplet, the discharge control unit 212 prevents the nozzle adjacent to that end nozzle (an example of an adjacent nozzle) from discharging. This reduces the discharge density and suppresses bending caused by airflow. Therefore, it is possible to suppress the occurrence of image quality degradation such as density unevenness and streaks at the joints compared to conventional mask processing. In the example shown in Figure 9-2, the discharge control unit 212 prevents the discharge of liquid from at least two adjacent nozzles to the end nozzles of heads 122a and 122b. In other words, the discharge control unit 212 prevents the discharge of liquid from at least two or more adjacent nozzles to the end nozzles of heads 122a and 122b. This enhances the effect of suppressing bending caused by airflow.

[0077] As described above, according to this embodiment, the mask pattern of the nozzle overlap region 300 at the head ends of adjacent heads 122a and 122b is arranged such that, in the X direction, printed dots formed by head 122a and printed dots formed by head 122b are alternately arranged, but in the Y direction, it is composed only of printed dots formed by the same head. This makes it possible to suppress the occurrence of density unevenness and streaks in the nozzle overlap region 300 at the head ends of two adjacent heads 122a and 122b caused by differences in the characteristics of the drive frequency of the ejected droplet amount between the two heads 122a and 122b, or by differences in positional misalignment or droplet velocity between the two heads 122a and 122b, thereby making the image quality of the nozzle overlap region 300 at the head ends of adjacent heads 122a and 122b uniform.

[0078] Furthermore, according to this embodiment, even if a positional shift (Y-shift) ΔY occurs in the Y direction between the two heads 122a and 122b, it is possible to suppress the occurrence of image quality degradation such as density unevenness and streaks in the nozzle overlap region 300 between adjacent heads 122a and 122b.

[0079] The program executed by the image forming apparatus 100 of this embodiment is provided as a file in an installable or executable format, recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disc).

[0080] Furthermore, the program executed by the image forming apparatus 100 of this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program executed by the image forming apparatus 100 of this embodiment may be provided or distributed via a network such as the Internet.

[0081] Furthermore, the program executed by the image forming apparatus 100 of this embodiment may be pre-installed and provided in ROM or the like.

[0082] The program executed in the image forming apparatus 100 of this embodiment has a modular configuration that includes the above-described parts (color plate division data generation unit 211, ejection control unit 212). In actual hardware, the CPU (processor) reads the program from the storage medium and executes it, loading the above-described parts onto the main memory, and generating the color plate division data generation unit 211 and the ejection control unit 212 on the main memory.

[0083] (Second embodiment) Next, a second embodiment will be described.

[0084] The second embodiment differs from the first embodiment in that it reduces the utilization rate of the end nozzle of the head. In the following description of the second embodiment, the description of parts that are the same as in the first embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0085] Figure 10 shows an example of a mask pattern according to the second embodiment, and Figure 11 is a graph showing an example of nozzle utilization in the nozzle overlap region 300.

[0086] As shown in Figure 10, in the masking process of the nozzle overlap region 300 of the heads 122a and 122b, the discharge control unit 212 of the control unit 101 of this embodiment mixes printed dots formed by head 122a and printed dots formed by head 122b in the X direction, and creates a vertical striped mask pattern in the Y direction by continuously forming printed dots formed by the same heads 122a and 122b.

[0087] In the mask section A3 shown in Figure 9-1, described in the first embodiment, the printed dots formed by head 122a and the printed dots formed by head 122b were arranged alternately, one dot at a time, in the X direction. On the other hand, in this embodiment, the ejection control unit 212 of the control unit 101 reduces the nozzle utilization rate of heads 122a and 122b as it approaches the ends of heads 122a and 122b, as shown in Figures 10 and 11.

[0088] More specifically, as shown in Figure 10, the discharge control unit 212 of the control unit 101 sets the nozzles 3, 6, 8, 9, 11, and 12 from the head end to "use" in the nozzle row of the nozzle overlap region 300 of the head 122a, and the nozzles 1, 2, 4, 5, 7, and 10 from the head end to "not use". Also, the discharge control unit 212 of the control unit 101 sets the nozzles 3, 6, 8, 9, 11, and 12 from the head end to "use" in the nozzle row of the nozzle overlap region 300 of the head 122b, and the nozzles 1, 2, 4, 5, 7, and 10 from the head end to "not use".

[0089] In the examples shown in Figures 10 and 11, as in Figure 9-1, the ejection interval in the mask section A3 and the ejection intervals in the normal sections A1 and A2 for a single head are the same. As a result, the drive frequencies of the printed dots in the normal sections A1 and A2 and the mask section A3 are the same. Therefore, they are not affected by the characteristics of the drive frequency as shown in Figure 6, and the difference in droplet volume due to the difference in drive frequency characteristics as shown in Figure 7 does not occur.

[0090] Furthermore, in the examples shown in Figures 10 and 11, even if a positional misalignment (Y-shift) ΔY occurs in the Y direction between the two heads 122a and 122b, the mask pattern is a vertical stripe pattern that creates continuous printed dots formed by the same heads 122a and 122b in the Y direction, so the printed dots do not overlap as shown in Figure 8.

[0091] Furthermore, generally, nozzles closer to the very end of the liquid discharge head are more susceptible to airflow, which can cause bending or differences in characteristics such as crosstalk. However, in the examples shown in Figures 10 and 11, reducing the usage rate of the end nozzles of the two heads 122a and 122b can make image quality degradation due to airflow effects less noticeable.

[0092] Thus, according to this embodiment, in addition to the effects described in the first embodiment, by reducing the frequency of use of the end nozzles of the two heads 122a and 122b in the nozzle overlap region 300, the usage rate of the end nozzles of the liquid discharge head, which are prone to differences in characteristics such as bending and crosstalk due to the influence of airflow, can be reduced, and image quality degradation due to the influence of airflow can be made less noticeable.

[0093] (Third embodiment) Next, a third embodiment will be described.

[0094] The third embodiment differs from the first embodiment in that it uses a mask pattern that does not utilize the nozzle at the uppermost upstream end of the airflow associated with the carriage's movement in the Y direction. In the following description of the third embodiment, the parts that are the same as those in the first embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0095] Figure 12 shows an example of a mask pattern according to the third embodiment. As shown in Figure 12, the heads 122a and 122b of this embodiment have two rows of nozzles, each consisting of multiple nozzles. The two rows of nozzles on the heads 122a and 122b of this embodiment are obtained by redistributing the single row of nozzles from the first embodiment into two rows, alternating between each other.

[0096] As shown in Figure 12, in the masking of the nozzle overlap region 300, the ejection control unit 212 of the control unit 101 of this embodiment mixes printed dots formed by head 122a and printed dots formed by head 122b in the X direction, and creates a vertical striped mask pattern in the Y direction by continuously forming printed dots formed by the same heads 122a and 122b.

[0097] In the example shown in Figure 12, the carriage 121 moves from top to bottom in Figure 12. As shown in Figure 12, the head 122b is positioned upstream of the head 122a in the direction of movement of the carriage 121. As shown in Figure 12, the discharge control unit 212 of the control unit 101 in this embodiment disables the nozzle 2b of the nozzle row on the upstream side in the direction of movement of the carriage 121 in the nozzle overlap region 300 of the head 122b, which is susceptible to the effects of the airflow accompanying the movement of the carriage 121 in the Y direction.

[0098] In the example shown in Figure 12, as in Figure 9-1, the ejection interval in the mask section A3 for a single head is the same as the ejection interval in the normal sections A1 and A2. As a result, the printed dots in the normal sections A1 and A2 and the mask section A3 have the same drive frequency. Therefore, they are not affected by the characteristics of the drive frequency as shown in Figure 6, and the difference in droplet volume due to the difference in drive frequency characteristics as shown in Figure 7 does not occur. Furthermore, even if a positional shift (Y-shift) ΔY occurs in the Y direction between the two heads 122a and 122b, the mask pattern is a vertical stripe pattern in which the printed dots formed by the same heads 122a and 122b are continuous in the Y direction, so the printed dots do not overlap as shown in Figure 8.

[0099] Furthermore, in the example shown in Figure 12, the mask pattern does not use the nozzle on the upstream side in the direction of movement of the carriage 121, so image quality degradation caused by droplet bending due to airflow can be made less noticeable.

[0100] Furthermore, in this embodiment, the ejection control unit 212 of the control unit 101 will "disable" the nozzle 1b of the nozzle row at the uppermost position in the direction of movement of the carriage 121 in the nozzle overlap region 300 of the head 122a, which is susceptible to the effects of the airflow, if the airflow associated with the movement of the carriage 121 is reversed in Figure 12. This makes it applicable to multi-pass printing as well.

[0101] Thus, according to this embodiment, in addition to the effects described in the first embodiment, by not using the upstream nozzle in the nozzle overlap region 300 of the heads 122a and 122b in the direction of movement of the carriage 121 (the direction intersecting the row direction of the nozzle row), image quality degradation due to droplet bending caused by airflow can be made less noticeable.

[0102] In this embodiment, heads 122a and 122b having two rows of nozzles have been described, but the invention is not limited to this. Liquid discharge heads having eight rows of nozzles, as shown in Figure 13, or liquid discharge heads with other row configurations may also be used.

[0103] In this embodiment, a multi-pass method in which the carriage 121 reciprocates to dispense ink has been described, but it is not limited to this, and can also be applied to a line-head method in which the liquid ejection head is fixed and the medium is moved. In the case of a line-head method, a mask pattern can be used that does not use the upstream nozzle, which is susceptible to the influence of airflow in the medium transport direction (the direction intersecting the row direction of the nozzle row).

[0104] (Fourth embodiment) Next, a fourth embodiment will be described.

[0105] The fourth embodiment differs from the first embodiment in that it reduces the nozzle usage rate in the head end region where drip bending occurs. In the following description of the fourth embodiment, the description of parts that are the same as in the first embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0106] Figure 14 shows an example of a mask pattern according to the fourth embodiment, and Figure 15 shows an illustrative example of the discharge droplets in the end region of the liquid discharge head.

[0107] As shown in Figure 14, in the masking process of the nozzle overlap region 300 of the heads 122a and 122b, the discharge control unit 212 of the control unit 101 of this embodiment mixes printed dots formed by head 122a and printed dots formed by head 122b in the X direction, and creates a vertical striped mask pattern in the Y direction by continuously forming printed dots formed by the same heads 122a and 122b.

[0108] As shown in Figure 15, the heads 122a and 122b are capable of projecting discharge droplets a, which are ejected vertically (Z-direction) from the center of the heads 122a and 122b toward the medium 40, onto the target position on the medium 40.

[0109] On the other hand, as shown in Figure 15, when the heads 122a and 122b eject droplets b perpendicularly toward the medium 40 from their head ends, the droplets are carried away by the airflow at the ends, causing the droplets to land at a position different from the target position on the medium 40. Note that Figure 15 shows a case where the droplets land at the target position on the medium 40 curves outward from the head, but depending on conditions such as the drive frequency, droplet size, and print gap, they may also curve towards the center of the head. Thus, when many ejected droplets b ejected from the head ends by the heads 122a and 122b are used in the mask pattern of the nozzle overlap region 300, there is a problem in that image quality degradation becomes significant.

[0110] Therefore, as shown in Figure 14, the discharge control unit 212 of the control unit 101 in this embodiment makes the distance X1 from the outermost nozzle to the second-end nozzle in the nozzle overlap region 300 of the head 122a longer than the distance X2 from the second-end nozzle to the nozzles inside the second-end nozzle. This reduces the utilization rate of the nozzles in the head end region of the head 122a where droplet bending occurs, making image quality degradation less noticeable.

[0111] More specifically, as shown in Figure 14, the discharge control unit 212 of the control unit 101 sets the nozzles 1, 6, 8, 9, 10, and 11 from the head end to "use" in the nozzle row of the nozzle overlap region 300 of the head 122a, and the nozzles 2, 3, 4, 5, 7, and 12 from the head end to "not use". Also, the discharge control unit 212 of the control unit 101 sets the nozzles 1, 6, 8, 9, 10, and 11 from the head end to "use" in the nozzle row of the nozzle overlap region 300 of the head 122b, and the nozzles 2, 3, 4, 5, 7, and 12 from the head end to "not use".

[0112] In the example shown in Figure 14, as in Figure 9-1, the ejection interval in the mask section A3 for a single head is the same as the ejection interval in the normal sections A1 and A2. As a result, the printed dots in the normal sections A1 and A2 and the mask section A3 have the same drive frequency. Therefore, they are not affected by the characteristics of the drive frequency as shown in Figure 6, and the difference in droplet volume due to the difference in drive frequency characteristics as shown in Figure 7 does not occur. Furthermore, even if a positional shift (Y-shift) ΔY occurs in the Y direction between the two heads 122a and 122b, the mask pattern is a vertical stripe pattern in which the printed dots formed by the same heads 122a and 122b are continuous in the Y direction, so the printed dots do not overlap as shown in Figure 8-1.

[0113] Thus, according to this embodiment, in addition to the effects described in the first embodiment, by widening the distance between nozzles used towards the ends of the liquid discharge head, the nozzle utilization rate in the head end region of the liquid discharge head, where droplet bending due to airflow is likely to occur, can be reduced, thereby making image quality degradation less noticeable.

[0114] In this embodiment, heads 122a and 122b having two rows of nozzles have been described, but the invention is not limited to these, and liquid discharge heads having eight rows of nozzles as shown in Figure 16, or liquid discharge heads with other row configurations may also be used. In the example shown in Figure 16, the distance X1 from the outermost nozzle used in the X direction to the second-end nozzle used in the nozzle overlap region 300 of head 122a is made longer than the distance X2 between the second-end nozzle used and the nozzles used further inside.

[0115] (Fifth embodiment) Next, a fifth embodiment will be described.

[0116] The fifth embodiment differs from the first embodiment in that the nozzles of the heads 122a and 122b are laid out on a two-dimensional matrix, and the nozzles adjacent to the end nozzles of the heads 122a and 122b are nozzles adjacent in the longitudinal direction (X direction) of the heads 122a and 122b, and these adjacent nozzles do not discharge. In the following description of the fifth embodiment, the description of parts that are the same as in the first embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0117] Figure 17 shows an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the fifth embodiment. The example shown in Figure 17 is an example where the mask portion A3 is a nozzle overlap region 300 with 24 channels. In this embodiment, the nozzle density of heads 122a and 122b can be reduced compared to a one-dimensional nozzle arrangement, making it possible to suppress bending due to the discharged airflow. In this embodiment, even in the case of a nozzle arrangement on a two-dimensional matrix, bending due to the discharged airflow can be further suppressed by not discharging from adjacent nozzles (nozzles adjacent in the longitudinal direction of heads 201a and 201b) to the nozzles at the ends of heads 122a and 122b. In the example shown in Figure 17, the discharge control unit 212 does not discharge from the end nozzles of heads 122a and 122b to two adjacent nozzles.

[0118] Thus, according to the fifth embodiment, by not discharging air from at least two nozzles from the end nozzles of the heads 122a and 122b, the effect of suppressing bending due to airflow can be further enhanced.

[0119] (Sixth embodiment) Next, a sixth embodiment will be described.

[0120] The sixth embodiment differs from the fifth embodiment in that the nozzles of the heads 122a and 122b are laid out on a two-dimensional matrix, the adjacent nozzles of the end nozzles of the heads 122a and 122b are nozzles adjacent to the heads 122a and 122b in the longitudinal direction (X direction) or the short direction (Y direction), and the adjacent nozzles of the end nozzles of the heads 122a and 122b do not discharge. In the following description of the sixth embodiment, the description of parts that are the same as in the fifth embodiment will be omitted, and the parts that differ from the first embodiment will be described.

[0121] Figure 18 shows an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the sixth embodiment. The example shown in Figure 18 is an example in a nozzle overlap region 300 with 24 channels in the mask section A3. In this embodiment, the nozzle density of the heads 122a and 122b can be reduced compared to a one-dimensional nozzle arrangement, thereby suppressing bending due to the discharged airflow. In this embodiment, even in the case of a nozzle arrangement on a two-dimensional matrix, the discharge control unit 212 can further suppress bending due to the discharged airflow by not discharging adjacent nozzles (nozzles that are close (adjacent) in the X and Y directions) to the end nozzles of the heads 122a and 122b.

[0122] Thus, while the fifth embodiment focused on adjacent nozzles in the X direction, in this embodiment, by not discharging from nozzles adjacent not only in the X direction but also in the Y direction, the effect of suppressing bending due to airflow can be further enhanced.

[0123] (Seventh Embodiment) Next, a seventh embodiment will be described.

[0124] The seventh embodiment differs from the sixth embodiment in that it does not discharge as much material from the peripheral nozzles of the end nozzles of heads 122a and 122b. In the following description of the seventh embodiment, the parts that are the same as those of the sixth embodiment will be omitted, and the parts that differ from the sixth embodiment will be described.

[0125] Figure 19 shows an example of a mask pattern in a two-dimensional matrix nozzle arrangement according to the seventh embodiment. In the example shown in Figure 19, the mask portion A3 is an example in a 24-channel nozzle overlap region 300. In this embodiment, the discharge control unit 212 discharges fewer nozzles around the end nozzles compared to the sixth embodiment.

[0126] Thus, according to the seventh embodiment, by making the peripheral nozzles of the end nozzle non-discharging, the effect of suppressing bending due to airflow can be further enhanced.

[0127] In this application, "liquid dispensing device" refers to a device that includes a liquid dispensing head 122 or a liquid dispensing unit and drives the liquid dispensing head 122 to dispensing liquid. A liquid dispensing device includes not only devices that can dispensing liquid onto objects to which liquid can adhere, but also devices that dispensing liquid into air or into liquid.

[0128] This "liquid dispensing device" may also include means for feeding, transporting, and dispensing paper onto materials to which liquid can adhere, as well as pre-treatment devices, post-treatment devices, etc.

[0129] For example, "devices that dispense liquids" include image forming machines, which dispense ink to form images on paper, and three-dimensional molding machines, which dispense molding liquid into a powder layer formed in layers to create three-dimensional objects.

[0130] Furthermore, "devices that dispense liquid" are not limited to those that visualize meaningful images such as letters or figures through the dispensed liquid. For example, devices that form patterns that do not have meaning in themselves, or devices that create three-dimensional images, are also included.

[0131] The term "materials to which liquid can adhere" above refers to materials to which liquid can adhere, at least temporarily, including materials that adhere and solidify, or materials that adhere and penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and inspection cells. Unless otherwise specified, it includes all materials to which liquid can adhere.

[0132] The materials referred to as "materials to which liquid can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, etc., as long as liquid can adhere to them, even temporarily.

[0133] Furthermore, the "liquid" is not particularly limited, as long as it has the viscosity and surface tension to be discharged from the liquid discharge head 122, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements or electronic circuit resist patterns, and material liquids for 3D molding.

[0134] Furthermore, while a "liquid dispensing device" may include devices in which the liquid dispensing head 122 and the object to which the liquid can adhere move relative to each other, it is not limited to these. Specific examples include serial-type devices in which the liquid dispensing head 122 moves, and line-type devices in which the liquid dispensing head 122 does not move.

[0135] Other examples of "devices that dispense liquids" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the surface of the paper, and injection granulation devices that granulate fine particles of raw materials by spraying a composition liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0136] Examples of the present invention are as follows: <1> A liquid dispensing device having a nozzle row consisting of multiple nozzles arranged in a sequence, and a first, second head or head tip for selectively dispensing droplets from the nozzles, wherein the first, second head or head tip is installed with a nozzle overlap region at the end of the nozzle row in the row direction, Regarding the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head chip of the first and second heads or head chips, and when the end nozzle of the first head or head chip ejects a droplet, the nozzle adjacent to the first head of the first head or head chip adjacent to the end nozzle does not eject a droplet. A liquid dispensing device equipped with the following features. <2> The nozzle overlap region is provided such that the first head or head tip and the second head or head tip do not overlap in the main scanning direction, but overlap in the sub-scanning direction. <1> The liquid dispensing device described above. <3> The nozzle overlap region has twice the number of nozzles as the normal region. When the end nozzles of the first and second heads discharge, the adjacent nozzles of the first and second heads do not discharge. <1> or <2> The liquid dispensing device described above. <4> The adjacent nozzles of the end nozzles of the first and second heads shall not discharge in a continuous manner, at least two nozzles or more. <1> from <3> A liquid dispensing device as described in any one of the following. <5> The first and second heads have nozzles laid out on a two-dimensional matrix. The adjacent nozzles of the end nozzles of the first and second heads are nozzles adjacent in the longitudinal direction of the head. The nozzles adjacent to the end nozzles of the first and second heads do not discharge. <1> from <3> A liquid dispensing device as described in any one of the following. <6> The adjacent nozzles of the end nozzles of the first and second heads shall not discharge in a continuous manner, at least two nozzles or more. <5> The liquid dispensing device described above. <7> The first and second heads have nozzles laid out on a two-dimensional matrix. The adjacent nozzles of the end nozzles of the first and second heads are nozzles adjacent to the first and second heads in the longitudinal or transverse direction. The nozzles adjacent to the end nozzles of the first and second heads do not discharge. <3> The liquid dispensing device described above. <8> <1> from <7> A liquid dispensing device as described in any one of the following: At least one of the following: head tank, carriage, supply mechanism, maintenance and recovery mechanism, and main scanning and moving mechanism, An image forming apparatus equipped with the following features. <9> <1> from <7> An image forming apparatus having a liquid dispensing device as described in any one of the following. <10> A liquid dispensing device having a nozzle row consisting of multiple nozzles arranged in a sequence, and a first, second head or head tip for selectively dispensing droplets from the nozzles, wherein the first, second head or head tip is installed with a nozzle overlap region at the end of the nozzle row in the row direction, Regarding the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head tip of the first and second heads or head tips, and when the end nozzle of the first head or head tip ejects a droplet, the nozzle adjacent to the first head of the first head or head tip adjacent to the end nozzle does not eject a droplet in the ejection control process. A liquid dispensing method including [details omitted]. <11> A computer controls a liquid dispensing device having a first and second head or head tip that selectively dispenses droplets from a nozzle row consisting of multiple nozzles, wherein the first and second heads or head tip are installed with nozzle overlap regions at the ends of the nozzle row in the row direction. Regarding the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head chip of the first and second heads or head chips, and when the end nozzle of the first head or head chip ejects a droplet, the nozzle adjacent to the first head of the first head or head chip adjacent to the end nozzle does not eject a droplet. A program designed to function as such. [Explanation of symbols]

[0137] 100 Image forming apparatus 101 Control Unit 122 Liquid Dispensing Head 122a, 122b, 122c head 212 Discharge Control Unit 300 Nozzle overlap area [Prior art documents] [Patent Documents]

[0138] [Patent Document 1] Patent No. 3702711 [Patent Document 2] Patent No. 6155613 [Patent Document 3] Japanese Patent Publication No. 2006-264189 [Patent Document 4] Japanese Patent Publication No. 2007-8892

Claims

1. A liquid dispensing device having a nozzle row consisting of multiple nozzles arranged in a sequence, and a first and second head or head tip for selectively dispensing droplets from the nozzles, wherein the first and second heads or head tip are installed with nozzle overlap regions at the ends of the nozzle row in the row direction, Regarding the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head chip of the first and second heads or head chips, and when the end nozzle of the first head or head chip ejects a droplet, the nozzle adjacent to the first head of the first head or head chip adjacent to the end nozzle does not eject a droplet. A liquid dispensing device equipped with the following features.

2. The liquid dispensing apparatus according to claim 1, wherein the nozzle overlap region is provided such that the first head or head tip and the second head or head tip do not overlap in the main scanning direction, but overlap in the sub-scanning direction.

3. The nozzle overlap region is equipped with twice the number of nozzles as the normal region. The liquid dispensing device according to claim 1 or 2, wherein when the end nozzles of the first and second heads are used for dispensing, the nozzles adjacent to the end nozzles of the first and second heads are not used for dispensing.

4. The liquid dispensing device according to claim 1 or 2, wherein at least two or more adjacent nozzles of the end nozzles of the first and second heads do not dispense liquid in a continuous manner.

5. The first and second heads have nozzles laid out on a two-dimensional matrix. The adjacent nozzles of the end nozzles of the first and second heads are nozzles adjacent in the longitudinal direction of the head. The liquid dispensing device according to claim 1 or 2, wherein the nozzles adjacent to the end nozzles of the first and second heads do not dispense liquid.

6. The liquid dispensing device according to claim 5, wherein at least two or more adjacent nozzles of the end nozzles of the first and second heads do not dispense liquid in a continuous manner.

7. The first and second heads have nozzles laid out on a two-dimensional matrix. The adjacent nozzles of the end nozzles of the first and second heads are nozzles adjacent to the first and second heads in the longitudinal or transverse direction. The liquid dispensing device according to claim 3, wherein the nozzles adjacent to the end nozzles of the first and second heads do not dispense liquid.

8. A liquid dispensing device according to claim 1 or 2, At least one of the following: head tank, carriage, supply mechanism, maintenance and recovery mechanism, and main scanning and moving mechanism, An image forming apparatus equipped with the following features.

9. An image forming apparatus having a liquid dispensing device according to claim 1 or 2.

10. A liquid dispensing device having a nozzle row consisting of multiple nozzles arranged in a first, second head or head tip for selectively dispensing droplets from the nozzles, wherein the first, second head or head tip is installed with a nozzle overlap region at the end of the nozzle row in the row direction, With respect to the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head chip of the first and second heads or head chips, and when the end nozzle of the first head or head chip ejects a droplet, the nozzle adjacent to the first head of the first head of the first head or head chip adjacent to the end nozzle does not eject a droplet in the ejection control process. A liquid dispensing method including [specific component].

11. A computer controls a liquid dispensing device having a nozzle row consisting of multiple nozzles arranged in a sequence, with first and second heads or head tips for selectively dispensing droplets from the nozzles, and the first and second heads or head tips are installed with nozzle overlap regions at the ends of the nozzle row in the row direction. Regarding the mask pattern of the nozzle overlap region, the data in a direction parallel to the row direction of the nozzle row is composed of either pixel data from the first head or head chip of the first and second heads or head chips, and when the end nozzle of the first head or head chip ejects a droplet, the nozzle adjacent to the first head of the first head or head chip adjacent to the end nozzle does not eject a droplet. A program designed to function as such.

Images