Control device, ink-jet recording device, control method thereof, and program

Abstract

To reduce deterioration in an image quality while suppressing increase in component cost of an ink-jet recording device and so on.SOLUTION: A control device, which controls an ink-jet recording device which discharges an ink from a discharge p@ort and records an image, has control means for controlling discharge of the ink. The control means counts a dot count number, which is a number of ink drops discharged to each unit region of a unit region group including a plurality of predetermined unit regions, and controls discharge of the ink in an attractive unit region which is a unit region in which an image is recorded after the unit region group on the basis of the number of continuous unit regions in which the dot count number satisfies predetermined count condition.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a control device, an inkjet printing apparatus, a control method therefor, and a program. [Background technology]

[0002] In recent years, inkjet recording devices have become known that circulate ink along ink flow paths within the recording head in order to suppress ink thickening, which is one of the causes of image quality degradation, as disclosed in Patent Document 1. This allows fresh ink to be constantly supplied to the ejection orifices, thereby suppressing ink thickening near the ejection orifices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-008513 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the above-mentioned technology, ink viscosity increases due to an increase or decrease in the number of ink ejections, etc. In order to further suppress this increase in ink viscosity, it is conceivable to use a method such as increasing the size of the pump that circulates the ink, but this method creates new problems such as an increase in the cost of parts for the inkjet recording device.

[0005] Therefore, the present invention provides a control device, an inkjet printing apparatus, a control method thereof, and a program that can reduce deterioration in image quality while suppressing increases in the component costs of the inkjet printing apparatus. [Means for solving the problem]

[0006] In order to solve this problem, for example, a control device of the present invention has the following configuration: A control device for controlling an inkjet recording device that records an image by ejecting ink from an ejection port, a control means for controlling the ejection of ink; The control means Counting a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a predetermined plurality of unit areas; Based on the number of consecutive unit areas whose dot counts satisfy a predetermined count condition, ink ejection is controlled in a target unit area, which is a unit area on which an image is printed after the group of unit areas. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce deterioration in image quality while suppressing increases in the cost of parts for the inkjet recording apparatus. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall perspective view of an inkjet recording apparatus according to an embodiment. [Figure 2] FIG. 2 is an overall perspective view of a recovery unit according to the embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control system of the inkjet printing apparatus according to the embodiment. [Figure 4] FIG. 2 is a bottom perspective view showing the configuration of the print head and the buffer tank. [Figure 5] FIG. 2 is a diagram schematically illustrating the configuration of a print head and a buffer tank. [Figure 6] FIG. 2 is a partial perspective view of the chip as viewed from the bottom. [Figure 7] Schematic diagram of the bottom of the chip. [Figure 8] FIG. 10 is an enlarged cross-sectional view of the chip around the ejection port. [Figure 9] FIG. 4 is a diagram for explaining energy applied to a recording element. [Figure 10] FIG. 2 is a cross-sectional view of the vicinity of an ejection port of a non-ink circulation type recording head. [Figure 11]FIG. 2 is a cross-sectional view of the vicinity of an ejection port of an ink circulation type recording head. [Figure 12] 10A and 10B are diagrams illustrating the relationship between non-ejection time and deviation of landing positions. [Figure 13] FIG. 2 is a diagram schematically showing an image based on image data and a unit area. [Figure 14] 10 is a flowchart of a determination process for determining pulse energy according to the first embodiment. [Figure 15] 10 is a flowchart of a determination process for determining pulse energy according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] An embodiment will be described below. Fig. 1 is an overall perspective view of an inkjet recording apparatus (hereinafter simply referred to as a recording apparatus) according to an embodiment. The configuration of the inkjet recording apparatus 101 and its operation during recording will be outlined with reference to Fig. 1.

[0011] 1 is a so-called serial scan printer. The inkjet recording device 101 conveys a recording medium 103 in a Y direction (also called the conveying direction) and scans a recording head 110 in an X direction (also called the scanning direction) that is perpendicular to the conveying direction, thereby recording an image on the recording medium 103.

[0012] In the inkjet recording apparatus 101, the rotation of the transport roller rotates the spool 106, transporting the recording medium 103 held by the spool 106 in the Y direction. The recording medium 103 is transported while being sandwiched between a feed roller and a pinch roller, and is guided to a recording position (scanning area of ​​the print head) on a platen 104. A carriage unit 102 on which a print head 110 is mounted performs reciprocating scanning (also referred to as reciprocating movement) along a guide shaft 108 extending in the X direction. The inkjet recording apparatus 101 acquires a position signal of the carriage unit 102 obtained by an encoder 107 while the carriage unit 102 is reciprocatingly scanning. The ejection openings (also referred to as nozzles) of the print head 110 eject ink at a timing based on the position signal, and record an image on the recording medium 103 in a fixed bandwidth corresponding to the arrangement range of the ejection openings. The inkjet recording apparatus 101 transports the recording medium 103 and repeatedly records images at each bandwidth to record an image on the recording medium 103.

[0013] 2 is an overall perspective view of the recovery unit according to this embodiment, and the configuration and operation of the recovery unit will be described with reference to FIG.

[0014] The recovery unit 210 is disposed outside the printing area in the movement direction (X direction) of the carriage unit 102. The carriage unit 102 stops at a standby position outside the printing area as needed before the start of a printing operation and during the printing operation. The recovery unit 210 is disposed at a position facing the print head 110 when the carriage unit 102 stops at the standby position. The recovery unit 210 has a cap 211, a suction pump 213, a first wiper 221, and a second wiper 222.

[0015] The cap 211 is supported by an elevation mechanism (not shown) so that it can be raised and lowered, and moves between a raised position and a lowered position. When in the raised position, the cap 211 abuts against the print head 110 and covers (caps) the nozzle surface of the print head 110. By covering the nozzle surface of the print head 110, the cap 211 can prevent the nozzles of the print head 110 from drying out and evaporating ink during non-printing operations. The cap 211 can also suck ink from the print head 110 by driving a suction pump 213 (described later). During printing, the cap 211 is positioned in a lowered position to avoid interference with the print head 110, which moves together with the carriage unit 102. When the cap 211 is positioned in the lowered position, the print head 110 can perform preliminary ejection onto the cap 211 when it moves to a position facing the cap 211.

[0016] The first wiper 221 and the second wiper 222 wipe the nozzle surface of the print head 110. The first wiper 221 and the second wiper 222 are made of an elastic material such as rubber. Wipers are also called wiper blades. The two first wipers 221 wipe one of the nozzle surfaces of two chips 403 (described later). The second wiper 222 wipes the entire nozzle surface including the nozzle array. The first wiper 221 and the second wiper 222 are fixed to a wiper holder 220. The wiper holder 220 moves along a wiper guide 223 in the front-to-rear direction indicated by the arrow W in the figure (the direction in which the nozzles are arranged in the print head, i.e., the Y direction). When the recording head 110 is positioned at the standby position, the wiper holder 220 moves in the direction of arrow W (one direction), thereby performing a wiping operation in which the first wiper 221 and the second wiper 222 wipe the ejection port surface while contacting the ejection port surface. When the wiping operation is completed, the carriage unit 102 moves away from the area where the wiping operation is performed. Thereafter, the wiper holder 220 moves to return the first wiper 221 and the second wiper 222 to their original positions (the positions before the wiping operation).

[0017] While this embodiment includes a first wiper 221 and a second wiper 222, a configuration including only one of these wipers may be used. The wiper in this embodiment is made of an elastic material such as rubber, but it may also be made of a porous material that absorbs ink. The wiper may be a vacuum wiper capable of sucking the ejection port surface. While wiping is performed only when the wiper moves in one direction in this embodiment, it may also be performed when the wiper moves back and forth in both directions. In this embodiment, the wiping direction is the direction in which the ejection ports are arranged in the print head (the Y direction), but it may also be a direction intersecting (perpendicular to) this direction (the direction in which the ejection port array is arranged, the X direction). The ejection port surface may be wiped by moving the carriage unit 102 in the scanning direction while the wiper is fixed. The first wiper 221 and the second wiper 222 may move in both the X and Y directions. In a configuration using multiple wiping members or wiping in different directions, the recovery units may be located separately. In this case, the recovery unit 210 may be divided and arranged in the vicinity of the standby position of the carriage unit 102 and on the opposite side across the recording medium.

[0018] The suction pump 213 is driven when the cap 211 covers the ejection port surface of the print head 110, making the interior of the print head 110 a substantially sealed space. This causes the suction pump 213 to generate negative pressure inside the cap 211, performing a suction operation to suck ink from the print head 110. This suction operation is performed when filling the print head 110 with ink from the ink tank 202 (initial filling), or when sucking and removing dust, solidified matter, air bubbles, etc. from inside the ejection ports (suction recovery). The cap 211 is connected to a waste ink absorber (not shown) via a flexible tube 212.

[0019] The suction pump 213 is, for example, a tube pump. The suction pump 213, which is a tube pump, includes a holder with a curved surface that holds at least a portion of the tube 212, a roller that can press the held tube 212, and a roller support that rotatably supports the roller. The suction pump 213 rotates the roller support in a predetermined direction, thereby rotating the roller while compressing the tube 212. This causes the suction pump 213 to generate negative pressure inside the cap 211 and suck ink from the print head 110. The sucked ink is discharged into the waste ink absorber through the tube 212. The suction operation is also performed when preliminary ejection is performed on the cap 211 by the print head 110, and ink received in the cap 211 by the preliminary ejection is discharged. That is, by driving the suction pump 213 when the ink held in the cap 211 after preliminary ejection reaches a predetermined amount, the ink held in the cap 211 can be discharged into the waste ink absorber through the tube 212.

[0020] In this way, the recovery unit 210 performs a recovery operation to restore the ejection port surface to a normal state. The recovery operation may also be called a cleaning operation or a cleaning operation. The recovery unit 210 may also be called a maintenance unit that performs maintenance on the ejection port surface.

[0021] Normally, in the idle state, a cap 211 of the recovery unit 210 caps the ejection port surface of the print head 110. Therefore, prior to printing, the cap 211 opens the ejection port surface to enable the print head 110 or carriage unit 102 to scan. After opening, once data for one scan has been accumulated in the buffer, a carriage motor 205 (described later in FIG. 3) scans the carriage unit 102 to print an image on the print medium 103.

[0022] A carriage belt (not shown) can be used to transmit the driving force from the carriage motor 205 to the carriage unit 102. However, instead of a carriage belt, other driving methods can be used, such as one that includes a lead screw that is rotationally driven by the carriage motor 205 and extends in the X direction, and an engagement portion that is provided on the carriage unit 102 and engages with a groove in the lead screw.

[0023] Ink supplied to the print head is supplied from an ink tank 202 (shown in Fig. 5, which will be described later) mounted inside the main body or in an external unit via a supply tube 105 through the carriage unit 102. Ink may be supplied from the ink tank 202 to the print head 110 using a pressurizing unit, or the ink may be supplied by capping the ejection port surface of the print head with a cap of a recovery unit and applying negative pressure to the inside of the cap with a suction pump to suck the ink.

[0024] Furthermore, the carriage may be equipped with one or more print heads capable of ejecting ink of multiple colors, or a single print head capable of ejecting ink of multiple colors may be equipped with the carriage.

[0025] 3 is a block diagram showing the configuration of a control system of the inkjet recording apparatus according to the embodiment, and the control system of the inkjet recording apparatus will be described with reference to FIG.

[0026] The inkjet recording apparatus 101 is connected to a data supply device such as a host computer 306 via an interface 307. The inkjet recording apparatus 101 has a recording control unit 301, motor drivers 308, 309, and 310, a transport motor 204, a carriage motor 205, a recovery unit motor 206, and a head driver 311.

[0027] The recording control unit 301 is, for example, a computer, and receives various data and control signals related to recording transmitted from a host computer 306. The recording control unit 301 has a CPU 302, a memory 303, an image processing unit 304, and a data processing unit 305.

[0028] CPU 302 stands for Central Processing Unit, is an arithmetic processing device, and is an example of control means. Instead of or in addition to CPU 302, recording control unit 301 may include other processors such as an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), or a QPU (Quantum Processing Unit). Some or all of the functions of recording control unit 301 are realized by one or more processors including CPU 302 reading out a computer program stored in storage or the like, loading the program into memory 303, and executing the program. Some or all of the functions of recording control unit 301 may also be realized by one or more circuits such as an ASIC (Application Specific Integrated Circuit) and a PLD (Programmable Logic Device) including an FPGA (Field Programmable Gate Array).

[0029] The CPU 302 controls motor drivers 308, 309, and 310 and a head driver 311 in accordance with control signals input via an interface 307. The CPU 302 processes input image data and signals sent from a head type signal generating circuit, which will be described later.

[0030] The memory 303 may be, for example, a random access memory (RAM). The memory 303 is capable of reading and writing data at high speed. The memory 303 may further include a non-volatile storage device such as a hard disk drive (HDD) or a solid state drive (SSD). The memory 303 stores input image data, intermediate multi-level gradation data, and a multi-pass mask.

[0031] The image processing unit 304 performs various types of image processing. The data processing unit 305 performs various types of data processing. The processing of the image processing unit 304 and the data processing unit 305 may be executed by the CPU 302.

[0032] The conveying motor 204 is controlled by a motor driver 308 to rotate and drive a conveying roller for conveying the recording medium 103 via a gear.

[0033] The carriage motor 205 has its rotation controlled by a motor driver 309, and drives the carriage unit 102 carrying the print head 110 in a reciprocating motion (also referred to as reciprocating scanning) along a guide shaft 108 extending in the X direction.

[0034] The recovery unit motor 206 is a motor mounted on the recovery unit 210, and its rotation is controlled by a motor driver 310. The recovery unit motor 206 switches the units to be driven by the camshaft, and operates the wiper guide 223 and the suction pump 213.

[0035] The head driver 311 is a driver that drives the print head 110, and when multiple print heads are mounted, multiple head drivers are provided corresponding to the number of print heads.

[0036] 4 is a bottom perspective view showing the configuration of the print head 110 and the buffer tank 401. The print head 110 in this embodiment has a plurality of chips 403 (two in this example).

[0037] Buffer tanks 401C, 401M, 401Y, and 401BK are provided above the print head 110. Buffer tanks 401C, 401M, 401Y, and 401BK are independent and each store one of four colors of ink: cyan, magenta, yellow, and black. Note that while buffer tanks 401C, 401M, 401Y, and 401BK are shown visible in FIG. 3 for the sake of explanation, buffer tanks 401C, 401M, 401Y, and 401BK are actually housed inside the print head 110.

[0038] The two chips 403 are arranged symmetrically across the center on the underside of the print head 110. The chip 403 has multiple ejection opening arrays 400 corresponding to each ink. The multiple ejection opening arrays 400 are arranged parallel to one another. Each ejection opening array 400 has 1,680 ejection openings arranged at intervals of 1,200 dpi. There is one ejection opening array 400 each for cyan, magenta, and yellow. There are two ejection opening arrays 400 for black. This allows the chip 403 to eject four colors using five ejection opening arrays 400.

[0039] The two chips 403 are arranged symmetrically in the center of the print head 110, so that an image can be printed using four colors of ink while suppressing unevenness due to the order in which the inks are ejected. The ejection openings in one color ejection opening array 400 may be arranged in the same line, or may be arranged alternately. Each of the 20 ejection opening arrays 400 may have 840 ejection openings spaced at 600 dpi intervals.

[0040] Fig. 5 is a diagram showing a schematic configuration of the print head 110 and the buffer tank 401. Fig. 5 is a schematic diagram of a flow path for one color, but as described above, it is assumed that the buffer tank 401 and flow paths for four colors, cyan, magenta, yellow, and black, are configured in one print head 110.

[0041] The recording head 110 and the buffer tank 401 have, as ink flow paths, a chip 403, a joint 404, a filter 405, a first pressure chamber 406, a second pressure chamber 407, a pump 408, a common supply flow path 409, a common recovery flow path 410, a valve 411, and a valve 412.

[0042] The joint 404 is connected to the ink tank 202 via a supply tube 105 that passes through the inside of the carriage unit 102. The joint 404 allows ink supplied from the ink tank 202 to flow to a filter 405 of the buffer tank 401 via the supply tube 105.

[0043] The filter 405 allows the ink to pass through and flow to the first pressure chamber 406 via the flow path in the buffer tank 401 and the valve 411 .

[0044] The first pressure chamber 406 is connected to the second pressure chamber 407 by a first flow path and a second flow path. Specifically, the first pressure chamber 406 is connected to the second pressure chamber 407 by a first flow path via a valve 412. Ink flows from the first pressure chamber 406 to the second pressure chamber 407 through the first flow path. The first pressure chamber 406 is connected to the second pressure chamber 407 by a second flow path via a pump 408. Ink flows from the second pressure chamber 407 to the first pressure chamber 406 through the second flow path.

[0045] Valves 411, 412 are provided at the inlet ports of the first pressure chamber 406 and the second pressure chamber 407, respectively, and open when a predetermined negative pressure is reached. The valve 411 at the inlet port of the first pressure chamber 406 is provided in the flow path between it and the filter 405. The valve 412 at the inlet port of the second pressure chamber 407 is provided in the first flow path between it and the first pressure chamber 406. The negative pressure at which the valve 412 at the inlet port of the second pressure chamber 407 opens is set to be higher than the negative pressure at which the valve 411 at the first pressure chamber opens.

[0046] Ink is supplied from the first pressure chamber 406 to a supply flow path (described later) of one or more ejection port arrays 400 arranged in the chip 403 via a joint 414 and a common supply flow path 409 configured in the print head 110. Then, the ink that has passed through the ejection port arrays 400 is returned to the second pressure chamber 407 from a recovery flow path (described later) in the chip 403, through a common recovery flow path 410 and a joint 415 configured in the print head 110.

[0047] Fig. 6 is a partial perspective view of chip 403 as viewed from the bottom. Fig. 7 is a schematic diagram of the bottom of chip 403. The configuration of the ejection ports and flow paths formed in chip 403, and the flow of ink will be described with reference to Figs. 6 and 7.

[0048] The chip 403 includes an orifice plate 420 , a substrate 430 , and a cover plate 440 .

[0049] The orifice plate 420 is provided on the bottom surface of the chip 403, i.e., on the recording medium side. A plurality of ejection ports 402 are formed on the surface of the orifice plate 420. The ejection ports 402 are arranged in a plurality of rows. When ink is supplied, a negative pressure is maintained such that a meniscus is formed on the ejection port surface where the ejection ports are formed.

[0050] One or more inlets 421 and one or more outlets 422 are formed on both sides of the outlet 402. One inlet 421 and one outlet 422 may be provided for one outlet 402, or one for two or more outlets 402.

[0051] The substrate 430 is provided between the orifice plate 420 and the cover plate 440. A recording element 423 is provided on the surface of the substrate 430 facing the orifice plate 420. The recording element 423 is electrically connected to a terminal 450 provided on the substrate 430. When a pulse is supplied to the recording element 423 via the terminal 450, the recording element 423 generates ejection energy for ejecting ink. The recording element 423 may be an electrothermal conversion element (heater) or a piezoelectric element. When a heater is used as the recording element 423, the heat generated by the heater causes ink in and near the ejection orifices 402 to bubble, and the resulting bubble-ejecting energy is used to eject ink from the ejection orifices 402. In addition, a temperature sensor (not shown) made of a diode for detecting the temperature of the substrate 430 is provided on the substrate 430. The temperature sensor is used for controlling ejection energy and ink temperature maintenance.

[0052] A supply flow path 431 and a recovery flow path 432 are formed in the substrate 430. The supply flow path 431 and the recovery flow path 432 are also referred to as back surface flow paths. The supply flow path 431 and the recovery flow path 432 are formed along the ejection port array direction. The supply flow path 431 and the recovery flow path 432 are connected to the ejection port 402 via the inlet 421 and the outlet 422.

[0053] The cover plate 440 is disposed opposite the orifice plate 420 across the substrate 430. The cover plate 440 covers the surfaces of the supply flow paths 431 and the recovery flow paths 432 opposite the substrate 430. Openings 441 are formed in the cover plate 440. The openings 441 are connected to the supply flow paths 431 and the recovery flow paths 432. The supply flow paths 431 and the recovery flow paths 432 are connected to the common supply flow path 409 and the common recovery flow path 410 of the recording head 110 via the openings 441. One or more openings 441 are provided for each supply flow path 431 and recovery flow path 432. The number of openings 441 may be the same as or different from the number of supply flow paths 431 and recovery flow paths 432.

[0054] Fig. 8 is an enlarged schematic cross-sectional view of chip 403 around the ejection orifice in Fig. 6. The structure around the ejection orifice and the flow of ink will be described with reference to Fig. 8.

[0055] Pressure chambers 801 filled with ink and ejection ports 802 for ejecting ink are formed inside the orifice plate 800. The pressure chambers 801 are part of a circulation path for circulating the ink.

[0056] A recording element 803 is provided on the substrate 810. The recording element 803 is disposed in a position facing the ejection port 802 across the pressure chamber 801. The recording element 803 functions as a heat generating unit. When energized, the recording element 803 ejects ink from the ejection port 802 by using thermal energy that causes film boiling in the ink. The substrate 810 is formed with supply channels 804 that are individually connected to the supply channels 431, and recovery channels 805 that are individually connected to the recovery channels 432. The supply channels 804 and the recovery channel 805 are part of a circulation path for circulating ink.

[0057] FIG. 9 is a diagram illustrating the energy applied to a printing element. One example of the energy applied to a printing element is split pulse energy applied to an electrothermal transducer. In FIG. 9, Vop is the driving voltage, P1 is the pulse width of the first pulse (hereinafter referred to as a preheat pulse) of the split heat pulses, P2 is the interval time, and P3 is the pulse width of the second pulse (hereinafter referred to as a main heat pulse). T1, T2, and T3 indicate the times used to determine P1, P2, and P3. When the driving voltage Vop is applied to the electrothermal transducer, it generates thermal energy in the ink near the ejection orifice, providing the electrical energy required for ejection. The value of the driving voltage Vop may be determined based on the area, resistance, and film structure of the electrothermal transducer, the liquid path structure of the printhead, and other factors. The split pulse driving method may sequentially apply pulses with widths of P1, P2, and P3.

[0058] The preheat pulse is an example of pre-energy, and is a pulse supplied before ink is ejected to control the ink temperature mainly near the ejection orifice. The pulse width P1 of the preheat pulse is set so that the thermal energy generated by the electrothermal transducer when the preheat pulse is applied does not cause bubbling in the ink.

[0059] The interval time P2 is set to provide a fixed time interval so that the preheat pulse and the main heat pulse do not interfere with each other, and to make the temperature distribution of the ink in the ink path uniform.

[0060] The main heat pulse is an example of main energy, and is a pulse (energy) that generates bubbles in the ink near the ejection orifice, causing the ink to be ejected from the ejection orifice, and plays an important role in the ejection control of this embodiment. The pulse width P3 of the main heat pulse may be determined by the area, resistance value, and film structure of the electrothermal conversion element, the structure of the ink flow path in the print head, the type of ink, etc.

[0061] (Problem description) The problem with this embodiment will now be described. Fig. 10 is a cross-sectional schematic diagram of the vicinity of the ejection ports of a non-ink circulation type print head. As shown in Fig. 10, pressure chambers 1001, ejection ports 1002, print elements 1003, and supply channels 1004 are provided around the ejection ports of the non-ink circulation type print head.

[0062] As shown in Figure 10(a), in a non-ink circulation type print head, during ejection, ink flows from a supply flow path 1004 through a pressure chamber 1001 into an ejection port 1002, and ink droplets are ejected. On the other hand, as shown in Figure 10(b), during non-ejection, ink is not supplied to the vicinity of the ejection port 1002. Therefore, the longer the non-ejection state continues, the more viscous the ink becomes near the ejection port 1002, causing deviations in the landing position due to fluctuations in the flight speed of ink droplets during ejection. It is known that this deviation in the landing position of a non-ink circulation type print head occurs from the time the non-ejection state lasts for about several hundred milliseconds, and worsens over time.

[0063] Fig. 11 is a cross-sectional view of the vicinity of the ejection ports of an ink circulation type print head. As shown in Fig. 11, a pressure chamber 1101, an ejection port 1102, a print element 1103, a supply flow path 1104, and a recovery flow path 1105 are provided around the ejection ports of the ink circulation type print head.

[0064] In an ink circulation type print head, during ejection, ink flows from a supply flow path 1104 through a pressure chamber 1101 into an ejection port 1102. A portion of the ink is ejected from the ejection port 1102 as ink droplets, and the remainder flows from the supply flow path 1104 through the pressure chamber 1101 to a recovery flow path 1105.

[0065] The impact position deviation that is a problem in this embodiment is mainly seen in non-ink circulation type print heads, but the formation of ink droplets does not monotonically worsen with respect to the non-ejection time.

[0066] FIG. 12 is a diagram illustrating the relationship between non-ejection time and the amount of deviation in landing position, which was discovered during the inventors' research. As shown in FIG. 12, the amount of deviation in landing position reaches a maximum during the non-ejection time T. The deviation in landing position occurs after a certain period of continuous ink droplet ejection at a high ejection frequency, and occurs even after a short non-ejection time of only a few milliseconds. It is known that the deviation in landing position is greatest at several tens of milliseconds and then disappears if the non-ejection time is sufficiently long. Depending on the configuration of the print head, the flight speed of ink droplets during the non-ejection time T may be slower or faster than normal. In other words, the deviation in landing position, which is a problem in this embodiment, occurs after a certain period of continuous ink droplet ejection at a high ejection frequency, and becomes large within a specific time range during the non-ejection state immediately thereafter.

[0067] The reason why this deviation in the landing position becomes the largest is presumed to be as follows: Normally, in an ink circulation type print head, the ink is pressurized by a pressure circulation pump while the device is running, regardless of whether it is ejecting or not. This pressurization pushes the ink from the supply flow path 804 side to the recovery flow path 805 side, as shown in Figure 8. As a result, fresh ink is always supplied near the ejection port 802, making it difficult for the ink to thicken.

[0068] However, when the ink droplet ejection frequency is high and the ink droplets are ejected continuously for a certain period of time or more, a state may occur in which ink is supplied to the pressure chamber 1101 from both the supply channel 1104 side and the recovery channel 1105 side, as shown in Figure 11(a). In this case, when ejection ends and the system transitions to a non-ejecting state, the flow of ink supply to the pressure chamber 1101 and the ejection port 1102 does not immediately recover. As a result, a state occurs in which ink is supplied only from the supply channel 1104 side, as shown in Figure 11(b).

[0069] The inventors speculate that when the non-ejection time becomes even longer and approaches time T, ink retention and thickening occur near the ejection orifice 1102, as shown in FIG. 11(c).

[0070] After a further non-ejection time has elapsed, the ink supply flow from the supply flow channel 1104 side to the recovery flow channel 1105 side is restored, as shown in FIG. 11(d).

[0071] Therefore, the impact position deviation that is a problem in this embodiment is believed to be caused by fluctuations in the flight speed of ink droplets ejected from the ejection port 1102 in the state shown in Figure 11(c). It is known that impact position deviation caused by this factor can be resolved by significantly increasing the amount of circulating ink, but this raises concerns about increased costs for the circulation pump and larger print heads. This embodiment was made in consideration of the above-mentioned problems, and by this embodiment, it is possible to suppress impact position deviation and reduce degradation of image quality while suppressing increases in the size of the device and component costs.

[0072] (First embodiment) A first embodiment will be described. In this embodiment, a CPU 302 counts the dots of ink droplets ejected for each unit area based on input image data, and determines the pulse energy to be applied to the printing elements according to the dot count. For example, the CPU 302 switches between a normal control method, in which the pulse energy is determined based on a value detected by a temperature sensor, and a control method different from the normal control method, according to the dot count.

[0073] Specifically, the CPU 302 of this embodiment counts a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a plurality of predetermined unit areas. The CPU 302 controls the ejection of ink onto a target unit area, which is a unit area on which an image is printed after the unit area group, based on the number of consecutive unit areas whose dot counts satisfy a predetermined counting condition.

[0074] Fig. 13 is a diagram schematically showing an image based on image data and unit areas. In Fig. 13, unit areas 1301 separated by dashed lines indicate unit areas on the image. A unit area of ​​interest 1302 is a unit area of ​​interest among the unit areas, and indicates an area that is the target of determination as to whether or not to change the pulse energy control. A unit area group 1305 indicates a group including multiple unit areas 1301 located before the unit area of ​​interest 1302 in the scanning direction.

[0075] The image data is input by the user via the interface and converted into binary data for each ink color after color separation and pass mask processing. The converted image data corresponds to the amount of image data printed by the print head in one scan. The print head of this embodiment has 1,680 ejection orifice neighborhoods for each color. Therefore, image data for one scan contains data for 1,680 pixels arranged in the direction in which the ejection orifice neighborhoods are arranged (Y direction). If the image width based on the image data is 42 inches and the printing resolution is 600 dpi, 25,200 pixels will be aligned in the scan direction (X direction) of the print head. This image data for one scan, consisting of 1,680 x 25,200 pixels, is divided into unit areas.

[0076] The size of the unit area 1301 and the unit area of ​​interest 1302 is preferably an integer multiple of the area (an example of an area to which the same energy is supplied) in which a group of printing elements driven by the same heat enable signal is provided as a signal value (heat enable signal) for generating the energy required to eject ink. The CPU 302 may acquire a dot count by counting the printing dots of each color for each unit area, and calculate the printing density of the image in one scan.

[0077] Dot count threshold A is used as the threshold for the dot count number. D and dot count threshold B D is preset. Dot count threshold A D is an example of the first dot count threshold. D is an example of the second dot count threshold. D is the dot count threshold B D The area 1303 shown in FIG. 13 is larger than the dot count threshold A D This is the area where the dot count is equal to or greater than the dot count threshold A. D The area 1304 indicates the dot count threshold B D or more, and dot count threshold A DThe white areas other than the area 1303 and the area 1304 are areas where the dot count threshold B D The area (also called the non-ejection area or blank area) where the number of dots is less than or equal to the dot count threshold B. D Being less than or equal to is another example of a count condition.

[0078] The CPU 302 calculates the dot count value in the unit area group 1305 when the dot count value is equal to or exceeds the dot count threshold A D The unit area where the number of dots is equal to or greater than the first dot count threshold is a predetermined area threshold A R If it is determined that a first unit area group exists, the CPU 302 determines whether or not a first unit area group exists in which the dot count threshold B D The unit area having a dot count below (below the second dot count threshold) is a predetermined area threshold B R or more (second region threshold or more), and a predetermined region threshold B R The CPU 302 determines whether there is a second unit area group that is continuous for a distance equal to or less than the third area threshold. Based on these determination results, the CPU 302 controls the ink ejection settings for the target unit area 1302. Specifically, when it determines that the first unit area group and the second unit area group exist, the CPU 302 changes the energy for ejecting ink droplets when it determines that either the first unit area group or the second unit area group does not exist.

[0079] Fig. 14 is a flowchart of the determination process when determining the pulse energy of the unit region of interest 1302. The CPU 302 executes the determination process shown in Fig. 14 by reading and executing a computer program stored in the memory 303 or the like.

[0080] In S1401, the CPU 302 acquires image data for one scan and performs dot count for each unit area of ​​the image from the image data. In this embodiment, the CPU 302 performs dot count for each unit area in the order in which ejection is performed. Here, since the print head 110 scans along the X direction, the CPU 302 performs dot count for each unit area along the X direction. When determining the pulse energy for the unit area of ​​interest 1302 shown in FIG. 13, the CPU 302 makes a determination starting from the unit area group 1305 located before the unit area of ​​interest 1302. Therefore, the CPU 302 performs dot count for the unit areas 1301 in the unit area group 1305 sequentially along the X direction.

[0081] In step S1402, the CPU 302 sets the dot count threshold A in the unit area group 1305 used for the determination. D The CPU 302 determines whether there is a unit area 1301 (area 1303) with a dot count equal to or greater than the dot count threshold A. D If it is determined that there is no unit area 1301 with a dot count equal to or greater than the dot count threshold A, the process proceeds to step S1407. D If it is determined that there exists a unit area 1301 with a dot count equal to or greater than this, the process proceeds to S1403.

[0082] Next, in step S1403, the CPU 302 determines whether the dot count is greater than or equal to the dot count threshold A. D The unit area where the threshold value is A R The CPU 302 determines whether the dot count number is equal to or exceeds the dot count threshold A D The unit area where the threshold value is A R If it is determined that the dot count is not greater than or equal to the dot count threshold A, the process proceeds to step S1407. D The unit area where the threshold value is A R If it is determined that the first unit area group exists, the process proceeds to S1404. In other words, if the CPU 302 determines that the first unit area group exists, the process proceeds to S1404.

[0083] The purpose of performing S1402 and S1403 is to determine the number of unit areas (here, the area threshold A) with high ejection frequencies before the unit area of ​​interest 1302, so that the ink inflow state near the ejection port is such that ink is supplied from both the supply flow path 1104 and the recovery flow path 1105 shown in FIG. 11(a). R ) to determine whether they exist consecutively. R If the dot count threshold A is set to 3, the determinations in S1402 and S1403 are both "Yes" when the image data is as shown in FIG. 13(a), FIG. 13(d), FIG. 13(e), or FIG. 13(f). D There is no unit area 1301 where the dot count threshold A D Even if there is a unit area 1301 that is greater than or equal to the area threshold A R If the area threshold A is not greater than 1000, ink is not supplied from both the supply flow path 1104 and the recovery flow path 1105 near the ejection port, and the problem of this embodiment is unlikely to occur. R is shown as 3, but the area threshold A R The steps S1402 and S1403 may be changed as appropriate. Steps S1402 and S1403 are an example of a first determination process.

[0084] In step S1404, the CPU 302 determines whether the dot count number is equal to or exceeds the dot count threshold B after the first unit area group in the unit area group 1305 to be determined. D The CPU 302 determines whether there is a unit area 1301 (non-ejection area) where the dot count number is equal to or smaller than the dot count threshold B D If it is determined that there is no unit area 1301 where the dot count is equal to or smaller than the dot count threshold B, the process proceeds to step S1407. D If it is determined that the following unit area 1301 exists, the process proceeds to S1405.

[0085] Next, in step S1405, the CPU 302 calculates the dot count threshold B D The unit area 1301 that is below the area threshold B R and area threshold BR The CPU 302 determines whether the dot count threshold B D The unit area 1301 is the area threshold B R Above threshold B R If it is determined that the dot count threshold B D The unit area 1301 that is below the area threshold B R Above threshold B R In other words, if the CPU 302 determines that the second unit area group described above exists consecutively after the first unit area group in the image recording order (scanning direction), the process proceeds to S1406.

[0086] The purpose of performing S1404 and S1405 is to determine whether there is a non-ejection area following the area with high ejection frequency before the unit area of ​​interest 1302, where the ink inflow state near the ejection orifice will be in a state where ink stagnation occurs near the ejection orifice 1102 as shown in FIG. 11(c). R 3, area threshold B R If ' is 5, the determinations in S1402 and S1405 are all Yes in Fig. 13(a). S1404 and S1405 are an example of the second determination process.

[0087] As shown in Figure 13(d), the dot count threshold A D The dot count threshold B D If there is no unit area 1301 that satisfies the following condition, and if the dot count threshold B D The unit area that is less than or equal to the area threshold B R If the dot count threshold B is not exceeded, the ink inflow state will be as shown in FIG. 11(b), and the problem of this embodiment will not occur. D The unit area 1301 that is below the area threshold B RIf the number of consecutive occurrences is greater than ', the ink inflow state is in the normal state shown in FIG. 11(d), and the problem of this embodiment is unlikely to occur. R 3, area threshold B R ´ is shown as 5, but the area threshold B R and area threshold B R ´ may be changed as appropriate.

[0088] In S1407, which is executed if any of the determinations in S1402 to S1405 is No, the CPU 302 may determine and control the pulse energy in the unit area of ​​interest 1302 in accordance with the value of a temperature sensor provided in the print head 110. In other words, in S1407, the CPU 302 ejects ink without changing the control of the pulse energy for ejecting ink from the normal control method.

[0089] On the other hand, in the case of the unit area of ​​interest 1302 shown in FIG. 13(a) where all the determinations in S1402 to S1405 are Yes, ink is supplied only from the supply channel 1104, as shown in FIG. 11(c), causing localized ink stagnation and thickening near the ejection port 1102. If ink droplets are ejected in this state, the flight speed of the ink droplets will be disturbed. Therefore, in S1406, which is executed when all the determinations in S1402 to S1405 are Yes, the CPU 302 changes the control of pulse energy applied to the recording element 423 from the normal control method in S1407 when image data is present in the unit area of ​​interest 1302, and ejects ink within the unit area of ​​interest 1302.

[0090] In the control of S1406, the CPU 302 determines whether to increase or decrease the pulse energy so as to reduce fluctuations in the ink flight speed or maintain a constant flight speed. For example, the CPU 302 can increase the ink flight speed by increasing the pulse energy supplied to eject ink. A method for increasing the pulse energy includes, but is not limited to, lengthening the pulse width P1 of the preheat pulse (delaying the time T1). The pulse energy can also be increased by lowering the drive voltage Vop. This is because the volume of ink heated around the heat generating element varies depending on the drive voltage Vop. If the drive voltage Vop is high, film boiling occurs around the heat generating element before the ink around the heat generating element is sufficiently heated, causing ink droplets to be ejected. On the other hand, if the drive voltage Vop is low, a large volume of ink is heated around the heat generating element before film boiling occurs, which reduces the viscosity of the ink near the ejection port 1102 and increases the flight speed. For the same reason, the pulse width P3 of the main heat pulse (from application time T2 to time T3) may be increased. Also, if it is sufficient to increase the temperature of the ink near the ejection port 1102 and reduce its viscosity, the effect of increasing the volume of ink heated can also be obtained by increasing the interval P2 (from time T2 to time T3) between the preheat pulse and the main heat pulse.

[0091] Furthermore, the CPU 302 may reduce the pulse energy given to the ink and slow down the flying speed of the ink depending on the determination result or the like.

[0092] When changing the pulse energy, a pulse table determined based on the magnitude of the pulse energy taking into account the above-mentioned details may be prepared in advance and stored in memory 303. In this case, CPU 302 may select a setting related to the pulse energy from the pulse table according to the determination results from S1402 to S1405.

[0093] As described above, the CPU 302 of the inkjet recording apparatus 101 controls the ejection of ink in a unit area of ​​interest based on the number of consecutive unit areas where the count of dots ejected in each unit area satisfies the count condition. This allows the inkjet recording apparatus 101 to suppress an increase in ink viscosity, suppress fluctuations in the ink flight speed, and suppress deterioration of image quality, while suppressing an increase in the size of the apparatus and an increase in parts costs.

[0094] For example, the inkjet recording apparatus 101 changes the control of the pulse energy of the unit area of ​​interest and changes the ejection of ink depending on whether there are a certain number (for a certain time) of unit areas ejected at a high ejection frequency before the unit area of ​​interest and whether there are a certain number (for a certain time) of unit areas that are in a non-ejection state following that unit area. This allows the inkjet recording apparatus 101 to suppress ink thickening and reduce disturbances in the flying speed of ink from the ejection ports, thereby suppressing deterioration of image quality while suppressing increases in the size of the apparatus and component costs.

[0095] Although this embodiment has been described using the serial scan printer shown in Figure 1, it can also be implemented in a full multi-type printer. In the case of a full multi-type printer, the above method is applied to the conveyance of the recording medium, not to a single scan of the recording head. In addition, in a full multi-type printer, the X direction in Figure 13 is the conveyance direction of the recording medium.

[0096] (Second embodiment) Even if the ink supply is disrupted due to ink stagnation and thickening, as shown in Figure 11(c), ink inflow will recover if a certain number of ink dots are ejected from the ejection ports. After the ink supply is restored, it is preferable to select pulse energy according to the temperature of the print head. This applies to the case where a certain number of ink droplets are ejected from the ejection ports after changing the pulse energy according to the first embodiment, even if the answers in S1402 to S1405 are all Yes, a certain number of ink droplets have been ejected from the ejection ports within the area that was designated as a non-ejection area in S1404 and S1405.

[0097] 15 is a flowchart of the determination process of the second embodiment. The determination process of the second embodiment will be described with reference to FIG.

[0098] S1501 to S1505 and S15060 are the same as S1401 to S1405 and S1406 in the first embodiment. When executing S15060, the CPU 302 changes the control of the pulse energy of the unit region of interest 1302 in the same way as in S1406.

[0099] In S1506, the CPU 302 counts dots from the first pixel (the next pixel in the first unit area group) of the non-ejection area determined as Yes in S1504 and S1505 to the pixel of interest to be determined, and calculates the cumulative dot count number. The pixel of interest may be a pixel within the unit area of ​​interest 1302. The CPU 302 calculates the cumulative dot count number when the cumulative dot count number is equal to or exceeds the cumulative dot count threshold C D The CPU 302 determines whether the integrated dot count is equal to or less than the dot count threshold C D If it is determined that the integrated dot count is equal to or less than the dot count threshold C D If it is determined that the number is not equal to or less than the predetermined number, the process proceeds to S1508. S1506 is an example of a third determination process.

[0100] In S1507, the CPU 302 continues the change made in S15060 to make the pulse energy applied to the recording element 803 larger or smaller than that in other regions.

[0101] In S1508, the CPU 302 sets and controls the pulse energy based on the temperature of the print head 110 detected by the temperature sensor. D If it is greater than , that is, if the process proceeds from S1506 to S1508, the pulse energy control that was changed in S1506 is returned to the normal control method for the pixels after the pixel of interest.

[0102] As described above, even when the inkjet recording apparatus 101 of the second embodiment changes the pulse energy control method from the normal control method, it returns the pulse energy control to the original control method (normal control method) after ejecting a predetermined number of ink droplets or more from the non-ejection state. This allows the inkjet recording apparatus 101 to further reduce fluctuations in the flight speed of ink droplets and suppress degradation of image quality. Furthermore, the inkjet recording apparatus 101 does not change the pulse energy control for pixels subsequent to the pixel of interest in the unit area of ​​interest, which satisfy the condition of S1506 described above and are unlikely to cause fluctuations in flight speed, thereby simplifying control.

[0103] This embodiment makes it possible to obtain high-quality printed materials such as CAD (Computer Aided Design) drawings, posters, and graphic art printed by an inkjet printing apparatus. This embodiment is particularly effective for objects such as ruled lines where image quality degradation due to misalignment of ink droplets is easily visible, but is not limited to this. Even in poster images printed in multiple colors, it is possible to suppress the phenomenon of colors appearing misaligned.

[0104] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0105] The disclosure of this specification includes the following control device, inkjet printing device, control method thereof, and program. (Item 1) A control device for controlling an inkjet recording device that records an image by ejecting ink from an ejection port, a control means for controlling the ejection of ink; The control means Counting a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a predetermined plurality of unit areas; Based on the number of consecutive unit areas whose dot counts satisfy a predetermined count condition, ink ejection is controlled in a target unit area, which is a unit area in which an image is printed after the group of unit areas. A control device characterized by: (Item 2) The control means executes a first determination process to determine whether or not a first unit area group exists in which unit areas having the dot count number equal to or greater than a first dot count threshold are consecutive for a number equal to or greater than a first area threshold; executes a second determination process to determine whether a second group of unit areas, the number of which is equal to or less than a second dot count threshold, is equal to or greater than a second area threshold and equal to or less than a third area threshold, is consecutively present after the first group of unit areas; Controlling ink ejection settings in the target unit area based on the determination result 2. The control device according to item 1, (Item 3) The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, When either the first unit area group or the second unit area group does not exist, the control of energy for ejecting ink droplets onto the target unit area is changed. 3. The control device according to item 2, (Item 4) The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, a third determination process is executed to count the number of dots from the first pixel of the second unit area group to the target pixel of the target unit area as an accumulated dot count, and to determine whether the accumulated dot count is equal to or less than a predetermined third dot count threshold value; Controlling ink ejection settings for the pixel of interest and subsequent pixels based on the determination result of the third determination process. 4. The control device according to item 2 or 3, (Item 5) The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, changing the control of energy for ejecting ink droplets onto the target unit area when either the first unit area group or the second unit area group does not exist; If it is determined in the third determination process that the integrated dot count number is equal to or less than a predetermined third dot count threshold, the change of the energy is continued; In the third determination process, when it is determined that the integrated dot count number is not equal to or less than a predetermined third dot count threshold, the change in the energy after the pixel of interest is returned. 5. The control device according to item 4, (Item 6) The first dot count threshold is greater than the second dot count threshold. 6. The control device according to any one of items 2 to 5, characterized in that: (Item 7) The area of ​​the unit area is an integer multiple of the area to which the same energy is supplied to eject ink. 7. The control device according to any one of items 1 to 6, characterized in that: (Item 8) When the control means determines in the first determination process that the first unit area group exists and determines in the second determination process that the second unit area group exists, Changing the time for supplying pre-energy before ink ejection; Changing the voltage of the main energy for ejecting ink; Varying the time for supplying the main energy; and Changing the interval during which no energy is supplied between the pre-energy and the main energy The ink ejection is controlled based on at least one of the above. 7. The control device according to any one of items 2 to 6, characterized in that: (Item 9) The control device according to any one of items 1 to 8, a print head having a print element that generates energy for ejecting ink and at least a part of a circulation path that circulates the ink; An inkjet recording apparatus comprising: (Item 10) A control method for controlling an inkjet recording apparatus that records an image by ejecting ink from an ejection port, comprising: a control step for controlling the ejection of ink; In the control step, Counting a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a predetermined plurality of unit areas; Based on the number of consecutive unit areas whose dot counts satisfy a predetermined count condition, ink ejection is controlled in a target unit area, which is a unit area in which an image is printed after the group of unit areas. 10. A method for controlling an inkjet recording apparatus comprising: (Item 11) A program for causing a computer to function as each means of the control device according to any one of items 1 to 9.

[0106] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0107] 101: Inkjet recording device, 110: Recording head, 302: CPU, 400: Discharge port array, 402, 802, 1002, 1102: Discharge port, 1301: Unit area, 1302: Attention unit area, 1305: Unit area group, 1303: Area.

Claims

1. A control device for controlling an inkjet recording device that records an image by ejecting ink from an ejection port, a control means for controlling the ejection of ink; The control means Counting a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a predetermined plurality of unit areas; Based on the number of consecutive unit areas whose dot count number satisfies a predetermined count condition, ink ejection is controlled in a target unit area, which is a unit area in which an image is printed after the group of unit areas. A control device characterized by:

2. The control means executes a first determination process to determine whether or not a first unit area group exists in which unit areas having the dot count number equal to or greater than a first dot count threshold are consecutive for a number equal to or greater than a first area threshold; executes a second determination process to determine whether a second group of unit areas, the number of which is equal to or less than a second dot count threshold, is equal to or greater than a second area threshold and equal to or less than a third area threshold, is consecutively present after the first group of unit areas; Controlling ink ejection settings in the target unit area based on the determination result 2. The control device according to claim 1.

3. The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, When either the first unit area group or the second unit area group does not exist, the control of energy for ejecting ink droplets onto the target unit area is changed.

3. The control device according to claim 2.

4. The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, a third determination process is executed to count the number of dots from the first pixel of the second unit area group to the target pixel of the target unit area as an accumulated dot count, and to determine whether the accumulated dot count is equal to or less than a predetermined third dot count threshold value; Controlling ink ejection settings for the pixel of interest and subsequent pixels based on the determination result of the third determination process.

3. The control device according to claim 2.

5. The control means When it is determined in the first determination process that the first unit area group exists and when it is determined in the second determination process that the second unit area group exists, changing the control of energy for ejecting ink droplets onto the target unit area when either the first unit area group or the second unit area group does not exist; If it is determined in the third determination process that the integrated dot count number is equal to or less than a predetermined third dot count threshold, the change of the energy is continued; In the third determination process, if it is determined that the integrated dot count number is not equal to or less than a predetermined third dot count threshold, the change in the energy from the pixel of interest onwards is reversed.

5. The control device according to claim 4.

6. The first dot count threshold is greater than the second dot count threshold.

3. The control device according to claim 2.

7. The size of the unit area is an integer multiple of the size of an area to which the same energy is supplied to eject ink.

2. The control device according to claim 1.

8. When the control means determines in the first determination process that the first unit area group exists and determines in the second determination process that the second unit area group exists, Changing the time for supplying pre-energy before ink ejection; Changing the voltage of the main energy for ejecting ink; Varying the time for supplying the main energy; and Changing the interval during which no energy is supplied between the pre-energy and the main energy The ink ejection is controlled based on at least one of the above.

3. The control device according to claim 2.

9. The control device according to claim 1 ; a print head having a print element that generates energy for ejecting ink and at least a part of a circulation path that circulates the ink; An inkjet recording apparatus comprising:

10. A control method for controlling an inkjet recording apparatus that records an image by ejecting ink from an ejection port, comprising: a control step for controlling the ejection of ink; In the control step, Counting a dot count, which is the number of ink droplets ejected onto each unit area of ​​a unit area group including a predetermined plurality of unit areas; Based on the number of consecutive unit areas whose dot count number satisfies a predetermined count condition, ink ejection is controlled in a target unit area, which is a unit area in which an image is printed after the group of unit areas.

10. A method for controlling an inkjet recording apparatus comprising:

11. A program for causing a computer to function as each means of the control device according to any one of claims 1 to 9.

Images