Liquid dispensing apparatus, liquid dispensing system, method, and program

Abstract

To provide a liquid dispensing device, liquid dispensing system, method, and program capable of suppressing streaks and unevenness that occur at joints. [Solution] The liquid ejection device according to the present invention is characterized by comprising: a first recording head that ejects droplets onto a recording medium in a first dot ejection pattern; a second recording head that ejects droplets onto the recording medium in a second dot ejection pattern, including a portion of the area on the recording medium where droplets have been ejected in the first dot ejection pattern; a reading means that reads an image formed by the first dot ejection pattern and the second dot ejection pattern from the recording medium; and an ejection control means that, based on the image read by the reading means, changes the dot configuration of the droplets of the first recording head and the droplets of the second recording head in the area on the recording medium where the first dot ejection pattern and the second dot ejection pattern are mixed.

Description

Technical Field

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

Background Art

[0002] Conventionally, there has been a liquid ejection device that forms an image by ejecting a liquid with recording heads arranged alternately on a recording medium. Due to insufficient adjustment of the recording heads or variations in the behavior of droplets, streaks occur in the image connection part between the dots formed by the droplets ejected from the first recording head and the dots formed by the droplets ejected from the second recording head.

[0003] Patent Document 1 discloses a technique for adjusting the ejection amount of the connection part based on the head gap for the purpose of suppressing white streaks in the connection part.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is a problem that unevenness occurs in the connection part when trying to suppress streaks.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a liquid ejection device, a liquid ejection system, a method, and a program capable of suppressing streaks and unevenness occurring in the connection part.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the liquid ejection device according to the present invention is characterized by comprising: a first recording head that ejects droplets onto a recording medium in a first dot ejection pattern; a second recording head that ejects droplets onto the recording medium in a second dot ejection pattern, such that the second dot ejection pattern includes a portion of the area on the recording medium where droplets have been ejected in the first dot ejection pattern; a reading means for reading an image formed by the first dot ejection pattern and the second dot ejection pattern from the recording medium; and an ejection control means for changing the dot configuration of droplets from the first recording head and droplets from the second recording head in the area on the recording medium where the first dot ejection pattern and the second dot ejection pattern are mixed, based on the image read by the reading means. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress streaks and unevenness that occur at the joint. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of the configuration of a liquid dispensing system according to an embodiment. [Figure 2] Figure 2 shows an example of the configuration of the head array in the image forming unit. [Figure 3] Figure 3 shows an example of the configuration of the hardware blocks of an image forming system. [Figure 4] Figure 4 shows an example of a drive waveform generated by the drive waveform generation circuit. [Figure 5] Figure 5 shows an example of the control flow executed by the control unit of the image forming system for the stitching process. [Figure 6] Figure 6 is a diagram illustrating the principle by which streaks and unevenness occur at the joint. [Figure 7] Figure 7 shows an example of the dot arrangement of ink that landed on the joint. [Figure 8]Figure 8 shows an example of applying a gradient pattern to the connecting section. [Figure 9] Figure 9 shows an example of a connecting pattern (part 1). [Figure 10] Figure 10 shows an example of the connecting pattern (part two). [Figure 11] Figure 11 shows an example of the third connecting pattern. [Figure 12] Figure 12 shows an example of the connecting pattern (number four). [Modes for carrying out the invention]

[0009] Embodiments of the liquid dispensing device, liquid dispensing system, method, and program will be described in detail below with reference to the attached drawings.

[0010] (Embodiment) The following describes an inkjet-type image forming system, which is an example of a liquid ejection system according to an embodiment. In the following, the image forming apparatus corresponds to the "liquid ejection apparatus," the paper feeding apparatus, drying apparatus, and paper discharge apparatus correspond to the "processing apparatus," the paper corresponds to the "recording medium," and the scanner corresponds to the "reading means."

[0011] However, the embodiments are not limited to these. Other configurations are also possible. For example, the "processing device" may consist of at least one of a paper feeder, a drying device, and a paper discharger. It may also consist of devices other than a paper feeder, a drying device, and a paper discharger.

[0012] In this application, the ejected liquid (droplet) is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, 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.

[0013] Energy generating means for discharging liquid include those using piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a diaphragm and a counter electrode.

[0014] A "liquid discharge unit" is a form of liquid discharge head. A liquid discharge unit integrates functional components and mechanisms with a liquid discharge head and includes an assembly of parts related to liquid discharge. For example, a "liquid discharge unit" may include a combination of a liquid discharge head with at least one of the following components: a head tank, carriage, supply mechanism, maintenance and recovery mechanism, main scanning movement mechanism, and liquid circulation device.

[0015] Here, integration includes, for example, cases where the liquid dispensing head and functional components or mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. Furthermore, the liquid dispensing head and functional components or mechanisms may be configured to be detachable from each other.

[0016] For example, as a liquid ejection unit, there is one in which a liquid ejection head and a head tank are integrated. Also, there is one in which a liquid ejection head and a head tank are integrated by being connected to each other with a tube or the like. Here, a unit including a filter can also be added between the head tank and the liquid ejection head of these liquid ejection units.

[0017] Also, as a liquid ejection unit, there is one in which a liquid ejection head and a carriage are integrated.

[0018] Also, as a liquid ejection unit, there is one in which a liquid ejection head is movably held by a guide member that forms part of a scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated. Also, there is one in which a liquid ejection head, a carriage, and a main scanning movement mechanism are integrated.

[0019] Also, as a liquid ejection unit, there is one in which a cap member that is part of a maintenance and recovery mechanism is fixed to a carriage to which a liquid ejection head is attached, and the liquid ejection head, the carriage, and the maintenance and recovery mechanism are integrated.

[0020] Also, as a liquid ejection unit, there is one in which a tube is connected to a liquid ejection head to which a head tank or a flow path component is attached, and the liquid ejection head and a supply mechanism are integrated. Through this tube, the liquid from a liquid storage source is supplied to the liquid ejection head.

[0021] The main scanning movement mechanism shall also include a single guide member. Also, the supply mechanism shall include a single tube and a single loading unit.

[0022] The "image forming apparatus" includes an apparatus that has a liquid ejection head (also referred to as a liquid ejection unit) and drives the liquid ejection head to eject liquid. The apparatus for ejecting liquid includes not only an apparatus capable of ejecting liquid onto an object to which the liquid can adhere, but also an apparatus for ejecting the liquid into the air or into a liquid.

[0023] This "image forming apparatus" may also include transport control means for feeding, transporting, and discharging materials to which liquid can adhere, as well as pre-processing devices, post-processing devices, and other components.

[0024] For example, in addition to devices that eject ink to form images on paper, there are also three-dimensional modeling devices that eject a molding liquid onto a powder layer formed in layers to create three-dimensional objects.

[0025] Furthermore, the term "image forming apparatus" is not limited to those that visualize meaningful images such as characters or figures using a discharged liquid. For example, it also includes those that form patterns that do not have meaning in themselves, or those that create three-dimensional images.

[0026] 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.

[0027] 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.

[0028] Furthermore, while "image forming apparatus" includes devices in which a liquid dispensing head and an object to which liquid can adhere move relative to each other, it is not limited to this. Specific examples include serial type apparatuses in which the liquid dispensing head moves, and line type apparatuses in which the liquid dispensing head does not move.

[0029] Other types of "image forming apparatus" include processing liquid coating apparatuses that dispense processing liquid onto paper in order to apply the processing liquid to the surface of the paper for purposes such as modifying the surface of the paper, and injection granulation apparatuses that granulate fine particles of raw materials by spraying a composition liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0030] In this application, the terms image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0031] Figure 1 is a diagram showing an example of the configuration of a liquid ejection system according to an embodiment. In Figure 1, the configuration of an inkjet type image forming system, which is an example of a liquid ejection system, is shown.

[0032] The image forming system 1 shown in Figure 1 comprises an image forming apparatus 10, a paper feeding apparatus 20, a drying apparatus 30, and a paper discharge apparatus 50.

[0033] The paper feeder 20 is equipped with a paper feed tray 21 for stacking multiple sheets of paper P.

[0034] The image forming apparatus 10 is equipped with a paper carrying drum 11. Paper P fed from the paper feeder 20 is gripped at the leading edge by a paper gripper provided on the surface of the paper carrying drum 11, and is fed in the circumferential direction of the paper carrying drum 11 by the rotation of the paper carrying drum 11. In this example, the circumferential direction of the paper carrying drum 11 is the paper transport direction X. Multiple suction holes are formed on the surface of the paper carrying drum 11, and the generation of a suction airflow directed toward the inside of the paper carrying drum 11 by the suction device 12 guides the paper P along the surface of the paper carrying drum 11, and the paper P is fed in the paper transport direction X by the rotation of the paper carrying drum 11.

[0035] In the paper transport direction X, the image forming unit 200, a sensor 108-1 for detecting the paper P, and a scanner 140 for reading the image formed on the paper P are arranged opposite the surface of the paper carrying drum 11. Here, the image forming unit 200 corresponds to the "liquid discharge unit".

[0036] The image forming unit 120 is an inkjet-type liquid ejection unit, and as an example, it is equipped with four color head arrays (head array 400K, head array 400C, head array 400M, and head array 400Y).

[0037] The image forming apparatus 10 receives sheets of paper P one by one from the paper feeder 20, supports the paper P on the paper supporting drum 11, and sequentially ejects ink onto the paper P supported on the paper supporting drum 11 using head arrays 400K, 400C, 400M, and 400Y to form an image on the paper P.

[0038] The drying device 30 transports the paper P, which has had an image formed in the image forming device 10, using the transport mechanism 32, dries the image in the drying mechanism 31, and then transports the paper P to the paper discharge device 50.

[0039] The paper output device 50 loads the paper P, which is sequentially fed by the transport mechanism 32, into the paper output tray 51.

[0040] The control unit 100, whose configuration will be described in detail later, is a control unit that controls the operation of the entire image forming system 1. The operation unit 150 is a user interface for the user to operate the image forming system 1. The operation unit 150 may be a touch panel or a keyboard, for example.

[0041] Figure 2 shows an example of the configuration of the head array of the image forming unit 200. As shown in Figure 2, the image forming unit 200 is equipped with a black (K) head array 400K, a cyan (C) head array 400C, a magenta (M) head array 400M, and a yellow (Y) head array 400Y, in order from the upstream side in the paper transport direction (paper transport direction X) of the paper P.

[0042] Head arrays 400K, 400C, 400M, and 400Y are each equipped with four recording heads, each having two rows of nozzle rows 41. In other words, they have a configuration of 2 rows × 16 heads.

[0043] The head array 400K has four recording heads (recording head 40K-1, recording head 40K-2, recording head 40K-3, and recording head 40K-4) arranged in a staggered pattern. The other head arrays, 400C, 400M, and 400Y, also have four discharge heads arranged in a staggered pattern, each having two rows of nozzles 41, similar to the configuration of the head array 400K.

[0044] Each head array (head array 400K, head array 400C, head array 400M, and head array 400Y) is equipped with recording heads in a staggered arrangement, so that the end side of the nozzle row 41 of each recording head overlaps with the end side of the nozzle row 41 of other adjacent recording heads in the paper transport direction X, as shown by the dotted lines Oa, Ob, and Oc in Figure 2.

[0045] Figure 3 shows an example of the configuration of the hardware block of the image forming system 1. As shown in Figure 3, the image forming system 1 comprises a main control board 100 (corresponding to the control unit 100 shown in Figure 1), a head relay board 200, and an image processing board 300.

[0046] The main control board 100 includes a CPU 101, an FPGA (Field-Programmable Gate Array) 102, RAM 103, ROM 104, NVRAM (Non-Volatile Random Access Memory) 105, a motor driver 106, and a drive waveform generation circuit 107, among others.

[0047] The CPU 101 is responsible for the overall control of the image forming system 1. For example, the CPU 101 uses the RAM 103 as a workspace to execute various control programs stored in the ROM 104 and functions as a control unit. The CPU 101 outputs control commands to control various operations in the image forming system 1. In doing so, the CPU 101 communicates with the FPGA 102 and works in cooperation with the FPGA 102 to control various operations in the image forming system 1.

[0048] FPGA102 includes a CPU control unit 111, a memory control unit 112, an I2C control unit 113, a sensor processing unit 114, a motor control unit 115, a recording head control unit 116, a recording head impact position setting unit 117, and an image reading / analysis processing unit 118.

[0049] The CPU control unit 111 has the function of communicating with the CPU 101. The memory control unit 112 has the function of accessing the RAM 103 and ROM 104. The I2C control unit 113 has the function of communicating with the NVRAM 105.

[0050] The sensor processing unit 114 processes the sensor signals of the various sensors 108 provided in the image forming system 1. The various sensors 108 is a general term for the sensors provided in the image forming system 1, and includes sensors such as sensor 108-1.

[0051] The motor control unit 115 controls the motor driver 106 to drive various motors 109 provided in the image forming system 1. These various motors 109 include, for example, a paper transport motor P.

[0052] The recording head control unit 116 passes the head drive data, ejection synchronization signal LINE, and ejection timing signal CHANGE stored in the ROM 104 to the drive waveform generation circuit 107, causing the drive waveform generation circuit 107 to generate a common drive waveform signal Vcom. The common drive waveform signal Vcom generated by the drive waveform generation circuit 107 is input to the recording head driver 210 mounted on the head relay board 200.

[0053] The recording head impact position setting unit 117 adjusts the impact positions between rows of each recording head, between recording heads of the same color (recording head 40K-1, recording head 40K-2, recording head 40K-3, recording head 40K-4), and between head arrays of different colors (head array 400K, head array 400C, head array 400M, head array 400Y) based on the results obtained by the image reading / analysis processing unit 118. It also controls the connecting pattern.

[0054] The image reading / analysis processing unit 118 reads the image using the scanner 140 and performs analysis processing on the read image. The analysis process also determines whether the read image contains streaks or unevenness. Here, unevenness mainly refers to color unevenness.

[0055] The head relay board 200 has a recording head driver 210 and a piezoelectric element 211. In the example configuration shown in Figure 3, the drive waveform generation circuit 107 is located on the main control board 100 side of the main unit, and the recording head driver 210 is mounted on the head relay board 200 side for each row of recording heads (recording head 40K-1, recording head 40K-2, recording head 40K-3, recording head 40K-4). The drive waveform generation circuit 107 generates a drive waveform for each row of recording heads (recording head 40K-1, recording head 40K-2, recording head 40K-3, recording head 40K-4). The recording head driver 210 on the head relay board 200 drives the piezoelectric element 211 based on the drive waveform generated by the drive waveform generation circuit 107, causing ink droplets (liquid droplets) to be ejected for each row of recording heads (recording head 40K-1, recording head 40K-2, recording head 40K-3, recording head 40K-4).

[0056] The image processing board 300 processes the image data using the image processing unit 310 and outputs the result to the FPGA 102.

[0057] Figure 4 shows an example of a drive waveform generated by the drive waveform generation circuit 107. In this embodiment, as an example, ejection is controlled by selectively using three types of droplets: small, medium, and large. The ink droplets come in small, medium, and large sizes, with the volume of the ink droplets increasing in this order. The common drive waveform shown in Figure 4 is the common drive waveform output to the recording head driver 210. Based on instructions from FPGA 102, the drive waveform generation circuit 107 outputs a selection signal to the recording head driver 210 for one of the three types of droplets: small, medium, or large (the MN signal for small droplets, the MN signal for medium droplets, or the MN signal for large droplets, respectively, as shown in Figure 4).

[0058] When the recording head driver 210 outputs the small droplet MN signal shown in Figure 4, it drives the piezoelectric element 211 with the small droplet ejection waveform shown in phase P4 of the common drive waveform to eject a small droplet. Similarly, when the recording head driver 210 outputs the medium droplet MN signal, it drives the piezoelectric element 211 with the medium droplet ejection waveform shown in phases P3 and P4 of the common drive waveform to eject a medium droplet. Furthermore, when the recording head driver 210 outputs the large droplet MN signal, it drives the piezoelectric element 211 with the large droplet ejection waveform shown in phases P2 to P4 of the common drive waveform to eject a large droplet. Therefore, it is possible to control the ejection of small, medium, or large droplets for each nozzle.

[0059] In this embodiment, the overlapping areas shown by the dotted lines Oa, Ob, and Oc in Figure 2 are discharged by each overlapping recording head in a discharge pattern that combines different droplet types such as small droplets, medium droplets, and large droplets, thereby forming the dots of the connecting pattern.

[0060] The configuration of the dots in the connecting pattern is set by the discharge pattern (equivalent to a dot discharge pattern) applied to the overlapping area.

[0061] In the following, the modification of the discharge pattern (dot configuration) corresponding to the overlapping range is referred to as the bridging process.

[0062] Figure 5 shows an example of the control flow performed by the control unit 100 of the image forming system 1 for the stitching process. First, the control unit 100 uses the image forming unit 200 to form a test chart on the paper P (step S1).

[0063] Specifically, an ink droplet is ejected onto the paper P by a first recording head, and then the paper P is fed in the paper transport direction X, so that the area on the paper P where the ink droplet was ejected partially overlaps and an ink droplet is ejected again by a second recording head. A test chart is formed using this method.

[0064] Next, when the control unit 100 detects the paper P with the sensor 108-1, it reads the test chart formed on the paper P with the scanner 140, stores the read image in the NVRAM 105, and the image reading / analysis processing unit 118 analyzes the read image in the NVRAM 105 (step S2).

[0065] Next, the control unit 100 determines whether streaks or irregularities have been detected by analyzing the read image (step S3). If streaks or irregularities are detected (step S3: Yes determination), it performs a bridging process to apply a bridging pattern to the overlapping areas (step S4).

[0066] Next, the control unit 100 uses the image forming unit 120 to form the test chart again on the paper P (step S5), and then reads the newly formed test chart with the scanner 140 and performs analysis (step S6).

[0067] Then, the control unit 100 determines whether streaks or unevenness have been detected by analyzing the read image (step S7). If streaks or unevenness are detected (step S7: Yes determination), it returns to step S4 and repeats the process from the splicing process. Since there are multiple splicing patterns, it gradually switches from splicing patterns with small droplet sizes to splicing patterns with large droplet sizes until streaks or unevenness are suppressed.

[0068] Furthermore, if no streaks or irregularities are detected in step S3 or step S7 (No determination), the control unit 100 terminates the control flow executed for the connecting process.

[0069] Next, we will explain the joining process in detail. As mentioned above, streaks or unevenness occur in the overlapping areas indicated by the dotted lines Oa, Ob, and Oc in Figure 2. Even when a gradient pattern is used for ejection to suppress streaks, unevenness may occur instead of streaks.

[0070] Figures 6 to 8 are diagrams illustrating the principle of how streaks and unevenness occur at the joint. As shown in Figure 6, in this embodiment, the first recording head 40-1 and the second recording head 40-2 are arranged in a staggered pattern, with the ends of the first recording head 40-1 and the ends of the second recording head 40-2 overlapping in the paper transport direction X. The overlap is indicated by the dotted line O.

[0071] The arrangement of the first recording head 40-1 and the second recording head 40-2 corresponds, for example, in Figure 2, to the arrangement of heads of the same color, such as the right end of recording head 40K-1 and the left end of recording head 40K-2, the right end of recording head 40K-2 and the left end of recording head 40K-3, or the right end of recording head 40K-3 and the left end of recording head 40K-4.

[0072] TEST1 and TEST2, shown in Figure 6, are two examples of test charts formed on paper P by the first recording head 40-1 and the second recording head 40-2.

[0073] TEST1 is formed by ejecting ink droplets (liquid droplets) onto paper P using a first recording head 40-1 in a first dot ejection pattern, then feeding paper P in the paper transport direction X, and then ejecting ink droplets (liquid droplets) on paper P using a second recording head in a second dot ejection pattern, partially overlapping the area where ink droplets (liquid droplets) were ejected using the first dot ejection pattern.

[0074] In the paper P shown in Figure 6, the dots within the area of ​​frame 60-1 are formed by the first recording head 40-1 using the first dot ejection pattern, and the dots within the area of ​​frame 60-2 are formed by the second recording head 40-2 using the second dot ejection pattern. The dots formed by the second dot ejection pattern are included in a portion of the area on the paper P where dots are formed by the first dot ejection pattern. Therefore, in the area where the areas of frame 60-1 and frame 60-2 shown in Figure 6 overlap, the first dot ejection pattern and the second dot ejection pattern are mixed. This overlapping area is referred to as the "connecting area".

[0075] TEST2 illustrates a different result from TEST1. TEST2 also forms dots using the same operation as TEST1. In the paper P shown in Figure 6, the dots in the area of ​​frame 61-1 are formed by the first recording head 40-1 using the first dot ejection pattern, and the dots in the area of ​​frame 61-2 are formed by the second recording head 40-2 using the second dot ejection pattern. The area where the areas of frame 61-1 and frame 61-2 shown in Figure 6 overlap is the "joint area".

[0076] Both TEST1 and TEST2 are completed images of the test chart formed on paper P by the first dot ejection pattern and the second dot ejection pattern.

[0077] Test chart TEST1 was created without stitching, resulting in the appearance of streaks L1 at the stitching points.

[0078] In test chart TEST2, a gradient pattern was used to connect the lines in order to eliminate the streaks L1, but as a result, unevenness L2 has occurred at the connecting points.

[0079] Figure 7 shows an example of the dot arrangement of ink that landed at the joint. As shown in Figure 7, if the jointing process is not performed as in test chart TEST1, due to insufficient head adjustment and variations in ink droplet behavior, ink droplet D2 ejected from the second recording head 40-2 moves in the direction of arrow A shown in Figure 7 and overlaps with ink droplet D1 that landed from the first recording head 40-1, and streaks L1 are generated by the overlap of these dots.

[0080] Figure 8 shows an example of applying a gradient pattern to the connecting section. As shown in Figure 8, this pattern is an ejection pattern in which, within the range of the connecting section W, the number of dots ejected by the second recording head 40-2 decreases and the number of dots ejected by the first recording head 40-1 increases as you move towards the first recording head 40-1 side, and the number of dots ejected by the second recording head 40-2 increases as you move towards the second recording head 40-2 side. In other words, it is called a gradient pattern because the ratio of dots ejected by the first recording head 40-1 and the ratio of dots ejected by the second recording head 40-2 gradually change like a gradient from the first recording head 40-1 side to the second recording head 40-2 side.

[0081] In Figure 8, the darkly shaded squares represent dots ejected by the first recording head 40-1, and the lightly shaded squares represent dots ejected by the second recording head 40-2. By applying such a gradient pattern, the behavior of ink droplets ejected from the first recording head 40-1 and the behavior of ink droplets ejected from the second recording head 40-2 can be dispersed, thereby suppressing the occurrence of streaks L1.

[0082] Furthermore, due to the influence of the drive frequency characteristics, unevenness L2 occurs in the area of ​​the connecting section W in this gradient pattern. In the connecting section W, the number of times that paper is continuously ejected from the same recording head nozzle 41 differs for each nozzle 41 with respect to the paper transport direction X, which can suppress the occurrence of streaks L1, but as a side effect, unevenness L2 occurs.

[0083] Figures 9 to 12 show examples of connecting patterns to reduce streaks L1 and unevenness L2. Here, the connecting pattern is a pattern that changes the configuration of the dots. Figure 9 shows an example of connecting pattern (part one).

[0084] In the bridging pattern (version 1) shown in Figure 9, the configuration is changed so that the first and second of the three types of drops (first, second, and third) are mixed between the first and second drop types, respectively, between the first and second recording heads 40-2.

[0085] As shown in Figure 9, the ejection pattern of the first recording head 40-1 mixes the first and second drop types. Figure 9 shows an example of an ejection pattern in which the first and second drop types are set in a staggered pattern. The ejection pattern of the second recording head 40-2 also mixes the first and second drop types. An example of an ejection pattern in which the first and second drop types are set in a staggered pattern in the gaps of the ejection pattern of the first recording head 40-1 is shown. By changing the dot configuration in this way, it is possible to reduce streaks and unevenness.

[0086] Figure 10 shows an example of the second bridging pattern. In the second bridging pattern shown in Figure 10, a third drop type is used in addition to the first recording head 40-1 and the second recording head 40-2, and the configuration is changed to one in which the first, second, and third drop types are mixed. The pattern shown in Figure 10 is just one example.

[0087] Note that the first and second drop types may be large and medium drop, medium and small drop, or large and small drop, respectively. The second drop type may be an ink drop (liquid drop) of any other size.

[0088] By changing the dot configuration in this way, it is possible to reduce streaks and unevenness.

[0089] Figure 11 shows an example of the third joining pattern. The third joining pattern shown in Figure 11 is a pattern in which a first drop type and a second drop type are set relative to the gradient pattern shown in Figure 8. The number of first drop types decreases as you move towards the center line of the joining section W, as shown in the graph in Figure 11, and the number of second drop types increases as you move towards the center line of the joining section W. In this method, the visibility of the pattern in the joining section W is reduced by the gradient, making it possible to further reduce streaks and unevenness.

[0090] Figure 12 shows an example of connecting pattern (number four). Connecting pattern (number four) is an example that includes voids in addition to different droplet types. One example is a pattern that includes voids, a second droplet type, and a third droplet type. The voids are areas where ink droplets are not ejected. In the configurations of connecting pattern (number one) to connecting pattern (number three), multiple droplet types are mixed, which may cause slight localized unevenness. By including voids as in connecting pattern (number four), it is sometimes possible to suppress localized unevenness.

[0091] Although several embodiments of the present invention have been described above, these embodiments and modifications are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments and modifications can be implemented in a variety of other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. Each of these embodiments and modifications is included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0092] 1. Image forming system 10 Image forming apparatus 20 Paper feeder 30 Drying equipment 40-1 First score head 40-2 Second score head 50 Paper ejection device 100 Main control board (control unit) 101 CPU 102 FPGA 103 RAM 104 ROM 105 NVRAM 106 Motor Driver 107 Drive waveform generation circuit 111 CPU Control Unit 112 Memory Control Unit 113 I2C Control Unit 114 Sensor Processing Unit 115 Motor Control Unit 116 Recording head control unit 117 Recording head impact position setting unit 118 Image Reading / Analysis Processing Unit 140 Scanners 200 Head relay board (image forming section) 300 Image Processing Board 400K 400C 400M 400Y Head Array P Paper W connecting section [Prior art documents] [Patent Documents]

[0093] [Patent Document 1] Japanese Patent Publication No. 2013-176891

Claims

1. A first recording head that ejects droplets onto a recording medium in a first dot ejection pattern, A second recording head ejects droplets on the recording medium using a second dot ejection pattern, such that the second dot ejection pattern includes a portion of the area where droplets were ejected using the first dot ejection pattern. A reading means for reading an image formed by the first dot ejection pattern and the second dot ejection pattern from the recording medium, Based on the image read by the reading means, a discharge control means changes the configuration of the dots of the droplets of the first recording head and the droplets of the second recording head in the area on the recording medium where the first dot discharge pattern and the second dot discharge pattern are mixed, A liquid dispensing device equipped with the following features.

2. The discharge control means changes some of the multiple dots in the range in the first dot discharge pattern and the second dot discharge pattern to droplets of different sizes. The liquid dispensing device according to claim 1.

3. The dot ejection patterns of the first dot ejection pattern and the second dot ejection pattern within the range are gradient patterns. The liquid dispensing device according to claim 1.

4. The discharge control means changes a portion of the plurality of dots in the range into gaps in the first dot discharge pattern and the second dot discharge pattern. The liquid dispensing device according to claim 1.

5. A liquid dispensing device according to any one of claims 1 to 4, The processing device for the recording medium, A liquid dispensing system equipped with the following features.

6. A method performed by a liquid dispensing device, A first recording head ejects droplets onto a recording medium in a first dot ejection pattern, A step of ejecting droplets using a second recording head in a second dot ejection pattern, such that the second recording head includes a portion of the area on the recording medium where droplets were ejected using the first dot ejection pattern, A step of reading the image formed by the first dot ejection pattern and the second dot ejection pattern from the recording medium using a reading means, A step of changing the configuration of the dots of the droplets of the first recording head and the droplets of the second recording head in the area on the recording medium where the first dot ejection pattern and the second dot ejection pattern are mixed, based on the image read by the reading means, A method that includes this.

7. On the computer, The first recording head ejects droplets onto the recording medium in a first dot ejection pattern, The steps include: ejecting droplets using a second recording head in a second dot ejection pattern, such that the second recording head includes a portion of the area on the recording medium where droplets were ejected using the first dot ejection pattern; The steps include reading the image formed by the first dot ejection pattern and the second dot ejection pattern from the recording medium using a reading means, A step of changing the configuration of the dots of the droplets of the first recording head and the droplets of the second recording head in the area on the recording medium where the first dot ejection pattern and the second dot ejection pattern are mixed, based on the image read by the reading means. A program that executes the command.

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