Printing device, control method of printing device, print head, and printing system

Abstract

A printing device, a control method of a printing device, a print head, and a printing system are disclosed. A printing unit includes a reaction liquid element row in which a plurality of printing elements are arranged in a first direction, a first element row in which a plurality of printing elements are arranged in the first direction, and a second element row in which a plurality of printing elements are arranged in the first direction. The reaction liquid element row, the first element row, and the second element row are arranged in a second direction perpendicular to the first direction. A scanning unit scans the printing unit in the second direction. A printing control unit controls a printing operation of the printing unit so that a ratio of a number of pixels that are allowed to eject a second ink to a number of pixels in a predetermined area on a print medium does not exceed a threshold value.

Description

Technical Field

[0001] This invention relates to a printing apparatus, a control method for the printing apparatus, a printhead, and a printing system. Background Technology

[0002] Printing apparatuses are known to print images on printing media by ejecting ink from a printhead onto the printing medium. Such printing apparatuses have recently been used in a variety of applications and therefore utilize a wide range of printing media. For example, printing apparatuses capable of performing printing on impermeable and low-permeability media have been proposed.

[0003] It is known that when printing images on printing media like this, in addition to ink containing coloring materials, a reactive liquid is used to suppress ink bleeding or beading by causing phenomena such as thickening through reaction with the ink. However, when using this reactive liquid, moisture generated when it is ejected from the nozzle adheres to the ink ejection surface, sometimes leading to defective ink ejection. To prevent this, Japanese Patent Publication No. 2010-089425 proposes an inkjet printing apparatus that suppresses moisture adhesion to the ink ejection surface by using an air suction mechanism to remove moisture from the moving area of ​​the head (the upper part of the platform). Summary of the Invention

[0004] According to one embodiment of the present disclosure, a printing apparatus is provided, the printing apparatus comprising:

[0005] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, a plurality of printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction. In the first element row, a plurality of printing elements for applying a first ink are arranged in a first direction. In the second element row, a plurality of printing elements for applying a second ink are arranged in a first direction. The reactivity of the second ink to the reaction liquid is lower than that of the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0006] The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium; and

[0007] The print control unit is configured to control the printing operation of the print unit such that the ratio of the number of pixels allowed to eject the second ink to the number of pixels in a predetermined area on the print medium does not exceed a threshold.

[0008] According to another embodiment of this disclosure, a method for controlling a printing apparatus is provided, the printing apparatus comprising:

[0009] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with a coloring material in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in a first direction. In the second element row, multiple printing elements for applying a second ink are arranged in a first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction. The method includes:

[0010] Scan the printing unit in the second direction relative to the printing medium; and

[0011] The printing operation of the printing unit is controlled such that the ratio of the number of pixels allowed to eject second ink to the number of pixels in a predetermined area on the printing medium does not exceed a threshold.

[0012] According to another embodiment of the present invention, a printhead is provided, the printhead including a row of reaction liquid elements, a first element row, and a second element row, wherein a plurality of printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction in the row of reaction liquid elements, a plurality of printing elements for applying a first ink are arranged in the first element row in the first direction, and a plurality of printing elements for applying a second ink are arranged in the second element row in the first direction, wherein the reactivity of the second ink to the reaction liquid is lower than that of the first ink to the reaction liquid, wherein the row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0013] According to another embodiment of the present disclosure, a printing system is provided, the printing system comprising:

[0014] Printing apparatus, including

[0015] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in the first direction. In the second element row, multiple printing elements for applying a second ink are arranged in the first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0016] The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium, and

[0017] A print control unit is configured to control the printing operation of the print unit; and

[0018] An information processing apparatus includes a determining unit configured to determine the amount of a second ink applied based on input image data, such that the amount of the second ink sprayed per unit time does not exceed a threshold.

[0019] The printing control unit controls the printing of the printing unit based on the applied amount determined by the determining unit.

[0020] Other features of the invention will become clear from the following description of exemplary embodiments (with reference to the accompanying drawings). Attached Figure Description

[0021] Figure 1A This is a view showing the appearance of an inkjet printing apparatus according to an embodiment;

[0022] Figure 1B This is a schematic diagram of the heating unit of the printing device;

[0023] Figure 2 This is a schematic diagram of the nozzle forming surface of the printhead unit;

[0024] Figure 3 It shows Figure 2 The diagram shows a cross-section of the nozzle-forming surface of the printhead unit.

[0025] Figure 4 This is a block diagram showing an outline of the configuration of the control system of the printing device;

[0026] Figure 5 This is a flowchart of the print data generation and processing.

[0027] Figure 6 This is a schematic diagram illustrating the mask pattern in a multi-pass printing method;

[0028] Figure 7 This is a view used to illustrate the multiple printing method;

[0029] Figure 8 (A) is a view showing an example of a table used for color conversion processing;

[0030] Figure 8 (B) is a view showing another example of a table used for color conversion processing;

[0031] Figure 8 (C) is a view showing yet another example of a table used for color conversion processing;

[0032] Figure 9This is a schematic diagram showing the mask pattern during 8 printing scans;

[0033] Figure 10A This is a flowchart illustrating an example of CPU processing;

[0034] Figure 10B It is a flowchart illustrating an example of CPU processing; and

[0035] Figure 11 This is a flowchart illustrating an example of CPU processing. Detailed Implementation

[0036] However, in the aforementioned prior art, the airflow generated by air suction may contaminate the lower surface of the printing medium, or in areas where suction ports are not formed, effective suction cannot be performed. Furthermore, the air suction mechanism may increase the size and cost of the device.

[0037] Embodiments of the present invention provide a technique for effectively suppressing defective ink ejection with a simple arrangement.

[0038] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the scope of the claimed invention. Several features are described in the embodiments, but this does not limit the invention to requiring all such features, and multiple such features can be suitably combined. Furthermore, in the drawings, the same reference numerals are given the same or similar configuration, and redundant descriptions are omitted.

[0039] It should be noted that, in this specification, "printing" refers not only to the formation of important information such as characters and graphics, but to the formation of any information, whether important or unimportant. "Printing" also refers to the formation of images, designs, patterns, etc., on a printing medium, as well as the processing of the medium itself, regardless of whether they are realized to be visually perceptible to humans.

[0040] In addition, "printing media" refers not only to paper used in general printing devices, but also to any material that can accept ink, such as cloth, plastic film, metal plate, glass, ceramics, wood and leather.

[0041] Furthermore, “ink” (hereinafter also referred to as “liquid”) should be interpreted broadly, just as the definition of “printing” mentioned above suggests. Therefore, “ink” refers to a liquid that, when applied to a printing medium, can be used to form images, designs, patterns, etc., to process the printing medium, or to process ink (e.g., the curing or insolubility of the colorant in the ink to be applied to the printing medium).

[0042] Furthermore, unless otherwise specified, "jet nozzle" generally refers to a jet nozzle or a liquid path connected to it. Additionally, a printing element for generating energy to eject ink as droplets is formed inside each jet nozzle, and in some cases, the jet nozzle including this printing element will be referred to as a "jet nozzle".

[0043] <First Embodiment>

[0044] (Overview of the printing device)

[0045] (Overall Configuration)

[0046] Figure 1A The appearance of an inkjet printing apparatus 100 (hereinafter also referred to as printing apparatus 100) according to an embodiment is shown. Figure 1B This is a schematic diagram of the heating unit of the printing apparatus 100. The printing apparatus 100 is a so-called serial scanning printer that prints images on the printing medium P by scanning the print head in the X direction (scanning direction) perpendicular to the Y direction (transfer direction) of the printing medium P.

[0047] Reference Figure 1A and Figure 1B Here is an overview of the printing apparatus 100. The printing apparatus 100 includes a carriage unit 2, a printhead unit 3 that can be attached to the carriage unit 2, a table 4, a roll 6, an encoder 7, a guide shaft 8, a transfer roller 10, a pressure roller 11, a take-up roller 14, and a heating unit 20. The printing apparatus 100 typically performs printing as follows.

[0048] First, the printing medium P is conveyed in the Y direction from the spool 6 holding the printing medium P by a conveyor motor (not shown) and a conveyor roller driven by a gear connected to the conveyor motor. The printing medium P conveyed from the spool 6 is further conveyed by the conveyor roller 10 and the pressure roller 11 pushed against the conveyor roller 10, and guided to the printing position (scanning area of ​​the printhead unit 3) on the platform 4.

[0049] Subsequently, carriage unit 2 scans (moves) printhead unit 3 back and forth along guide shaft 8 extending in the X direction via carriage motor (not shown). During this scanning process, printhead unit 3 performs jetting operations at timings based on position signals obtained by encoder 7, thereby printing an image on printing medium P with a predetermined bandwidth corresponding to the arrangement range of jet nozzles 30 of printhead unit 3. In this embodiment, carriage motor scans carriage unit 2 while data from one scan is accumulated in buffer, thereby performing printing as described above. Note that the printing apparatus 100 of this embodiment can perform so-called multipass printing, by which an image is printed in a unit area (1 / n band) on printing medium P by scanning printhead unit 3 multiple times (n times). This multipass printing will be described in detail later.

[0050] Note that the scan rate is variable; for example, it can be performed at a rate of 10 to 70 inches per second. Additionally, the print resolution is also variable, for example, it can be 300 to 2400 dpi (dots per inch: the number of ink dots per inch). The print media P is then transported after the scan, and printing is performed further in the next bandwidth. This allows printing to be performed across the entire print range of the print media.

[0051] It should also be noted that a carriage belt or similar device can be used to transmit driving force from the carriage motor to the carriage unit 2. However, instead of a carriage belt, another drive system can be used, such as a system that includes a lead screw extending in the X direction and rotating by the carriage motor, and a fitting portion arranged in the carriage unit 2 to engage with a groove of the lead screw.

[0052] Furthermore, the surface of the printhead unit 3 is typically covered when in the paused state. Therefore, the printhead unit 3 or carriage unit 2 can be set to a scannable state by opening the cover before the print media P reaches the printing position.

[0053] The printing medium P, which has passed through the printing area of ​​the printhead unit 3 and has been inked, is heated and dried by the heating unit 20. The heating unit 20 includes a heater 25 and a heater cover 26. The heater 25, supported by a frame (not shown), is mounted downstream of the carriage unit 2 in the Y direction (sub-scanning direction) where it scans back and forth in the X direction (main scanning direction), and uses heat to dry the liquid ink on the printing medium P. The heater cover 26, which covers the heater 25, effectively dissipates the heat from the heater 25 onto the printing medium P and protects the heater 25.

[0054] Practical examples of heater 25 include a heater with a sheath and a halogen heater. Note that heating unit 20 can also be mounted vertically above printhead unit 3, and can heat the printing medium with the printed image from above. Also note that heating unit 20 can be mounted vertically below table 4, and can heat the printing medium with the printed image from below. Although in Figure 1B Although not shown, the heating unit 20 can be used in conjunction with an infrared sensor or the like to control the maximum temperature of the printing medium. For example, a controller can be formed to control the temperature of the printing medium and perform control to keep the heating temperature of the printing medium constant.

[0055] In this embodiment, the heating unit 20 can also be used as a unit for forming a film by heating water-soluble resin particles in the printing medium P. The water-soluble resin particles are resins used to improve the scratch resistance of an image by forming a film when heated after being applied to the printing medium. In this case, it is desirable that the heating temperature is higher than the minimum film-forming temperature of the resin particles, and that most of the liquid components in the ink, such as water-soluble organic solvents, need to be evaporated during heating. Therefore, in the printing medium transport direction, the heating unit 20 has a temperature distribution sufficient to ensure the heating time required to supply the energy needed to evaporate most of the liquid components.

[0056] In this embodiment, the printing apparatus 100 includes a take-up reel 14. The printing medium P, which has been printed by the printhead unit 3 and heated by the heating unit 20, is taken up by the take-up reel 14 and formed into a roller-shaped take-up medium.

[0057] (Print head configuration)

[0058] Figure 2 This is a schematic diagram of the nozzle forming surface of the printhead unit 3. Figure 3 It shows Figure 2 The diagram shows a schematic cross-section of the nozzle-forming surface of the printhead unit 3. The printhead unit 3 of this embodiment includes two printheads 31 and 32. The chip of printhead 31 includes nozzle rows 35K (element rows 35K) for ejecting black ink (K) as an ink containing coloring material, nozzle rows 35m (element rows 35m) for ejecting light magenta ink (m), and nozzle rows 35M (element rows 35M) for ejecting magenta ink (M). In this embodiment, each of the black ink, light magenta ink, and magenta ink contains pigment as a coloring material. Light magenta ink is an ink having the same hue as magenta ink but a lower coloring material concentration than magenta ink. The hue of the black ink is different from that of the magenta ink. These inks will also be referred to hereinafter as pigment inks. The chip of printhead 32 has nozzle rows 35Tr (reaction liquid element rows) for ejecting a treatment liquid (Tr) that contains neither coloring material nor water-soluble resin particles. In this embodiment, the nozzle rows are arranged in the order of nozzle rows 35Tr, 35M, 35m, and 35K from left to right in the X direction. More specifically, the nozzle rows are arranged such that the distance between nozzle rows 35Tr and 35M is greater than the distance between nozzle rows 35M and 35m. Because the nozzle row 35Tr of the treated liquid is set relatively far apart, the effect of adhesion of water vapor (described later) of the treated liquid is suppressed. Similarly, the nozzle rows are arranged such that the distance between nozzle rows 35Tr and 35M is greater than the distance between nozzle rows 35m and 35K.

[0059] This embodiment employs the following arrangement: nozzle rows 35M, 35m, and 35K are arranged close to each other in the same printhead 31, but nozzle row 35Tr is formed in another printhead 32, i.e., it is positioned relatively far away from nozzle rows 35M, 35m, and 35K. This arrangement can suppress the mixing of the processing liquid and color ink, except for processing liquid moisture, when the processing liquid and color ink are arranged close to each other by using the same cap. On the other hand, from the viewpoint of preventing the mixing of processing liquid moisture during printing, which will be described later, this arrangement is not always necessary, so nozzle rows 35M, 35m, 35K, and 35Tr can also be arranged in the same printhead.

[0060] Note that the distance between the nozzle rows is not limited to the distances described above. For example, the processing liquid nozzle row 35Tr is typically arranged far away from other nozzle rows. Also note that each of the nozzle rows 35Tr, 35M, 35m, and 35K is formed by arranging 1280 nozzles 30 for spraying processing liquid or ink at a density of 1200 per inch in the Y direction (sub-scanning direction).

[0061] The ink jets 35Tr, 35M, 35m, and 35K are connected to ink tanks (not shown) that store their respective inks and supply ink from them. Note that printheads 31 and 32 and the ink tanks can be integrated or separate from each other. Alternatively, the ink tanks can be installed at a location spaced apart from the printheads 31 and 32 of the printing device 100 and connected to them using tubing or the like. In this case, a pump can be installed to supply ink from the ink tanks to the printheads 31 and 32.

[0062] Note that the detailed composition of black ink, light magenta ink, magenta ink, and processing liquid will be described later.

[0063] A temperature sensor mounted on the nozzle forming substrate detects the temperature of each of the printheads 31 and 32 in the printhead unit 3. For example, the temperature sensor may be a temperature-dependent sensor using the anode-cathode voltage of a diode.

[0064] Below, we will refer to Figure 3 The configuration of the ejector 30 will be explained below. Printheads 31 and 32 in this embodiment are thermal inkjet printheads. A thermal inkjet printhead includes a heating element that serves as the printing element. Ink is heated on the heating element and ejected from the ejector through the ejector by utilizing the film boiling phenomenon.

[0065] An upper plate member 55 is disposed on a heating element forming substrate 51. By disposing the upper plate member 55 on the heating element forming substrate 51 in this way, an injection port forming substrate 33 is formed. A liquid channel 53 is formed between the heating element forming substrate 51 and the upper plate member 55. The liquid channel 53 communicates with an injection port 30 formed in the upper plate member 55. A bubble release chamber is formed at the end of the injection port 30 in the liquid channel 53. In this bubble release chamber, a heating element 54 is disposed facing the injection port 30. During printing and pre-jetting operations, the heating element 54 is heated by... Figure 4 The drive circuit 307 shown in the diagram sends a signal to drive the liquid, thereby generating heat from the heating element 54 and locally heating the liquid. As a result, film boiling occurs in the liquid inside the bubble release chamber, and the resulting pressure ejects droplets from the ejection port 30. As described above, the printheads 31 and 32 of this embodiment include an ejection port 30 and a heating element 54 formed in a channel communicating with the ejection port 30. Note that the amount of droplets ejected from each ejection port is approximately 4 ng.

[0066] (Control Configuration)

[0067] Figure 4 This is a block diagram showing an outline of the configuration of the control system of the printing apparatus 100. The main control unit 300 includes a CPU 301, a ROM 302, a RAM 303, a memory 313, and an input / output port 304. The CPU 301 performs processing operations such as arithmetic operations, selection, judgment, and control, as well as printing operations. The ROM 302 stores control programs to be executed by the CPU 301. The RAM 303 is used as a print data buffer, etc. The memory 313 stores various information such as mask patterns. The input / output port 304 is connected to drive circuits 305, 306, 307, and 308 for driving the transfer motor (LF motor) 309, the carriage motor (CR motor) 310, the print heads 31 and 32, and the actuators in the heater 25, etc. The main control unit 300 is connected to a PC 312, which serves as a host computer, via an interface circuit 311.

[0068] (Data Processing)

[0069] Figure 5 This is a flowchart of the print data generation process to be executed by CPU 301. For example, CPU 301 reads the program stored in ROM 302 into RAM 303 and executes the program to implement this flowchart.

[0070] In step S1 (each step will be simply referred to as S1 etc. below), CPU 301 acquires image data (brightness data) represented by 8-bit 256-value information (0 to 255) of each of red (R), green (G) and blue (B) input from PC 312, which is the host computer, to the printing device 100.

[0071] In S2, the CPU 301 converts image data represented by R, G, and B into multi-level data represented by various types of ink to be used for printing the image data. This color conversion process generates multi-level data represented by 8-bit 256-value information (0 to 255) that determines the grayscale of the ink in a pixel group comprising multiple pixels. Furthermore, the CPU 301 in this embodiment utilizes (described later)... Figure 8 (A) to Figure 8 The color conversion table shown in (C) obtains the print duty for each color ink relative to the multi-level data (grayscale) used to determine the generated grayscale. In this case, print duty indicates the ratio of the number of pixels to which ink is allowed to be applied to the number of pixels in a predetermined area of ​​the printing medium. For example, when ink is allowed to be applied to all pixels in a predetermined area of ​​the printing medium, the print duty is 100% (so-called solid printing). As another example, when ink is allowed to be applied to half of all pixels in a predetermined area of ​​the printing medium, the print duty is 50%.

[0072] In S3, CPU 301 performs quantization of the aforementioned multi-level data, thereby generating quantized data (binary data) represented by 1-bit binary information (0, 1) determining whether each ink is sprayed or not at each pixel. In this step, the processing can be performed using various quantization methods such as error diffusion, binary signaling, and indexing. More specifically, CPU 301 generates the quantized data based on the multi-level data acquired in S2 and the print load value for each ink.

[0073] In S4, CPU 301 performs an allocation process that distributes quantized data to multiple scans of the printhead unit 3 relative to a unit area. This allocation process generates print data represented by 1-bit binary information (0, 1) determining whether each type of ink is ejected to each pixel or not in each of the multiple scans of a unit area of ​​the print medium. This allocation process is performed using a mask pattern that corresponds to the multiple scans and determines whether ink ejection to each pixel is allowed or not (see [link]). Figure 6 ).

[0074] The printhead ejects ink based on the print data generated as described above.

[0075] Note that the form in which the CPU 301 of the printing device 100 performs all the processes in S1 to S4 has been described, but it could also be in another form. An example is the form in which the PC 312 performs all the processes in S1 to S4. Another example is the form in which the PC 312 performs some processes while the printing device 100 performs the remaining processes.

[0076] (Multiple printing processes)

[0077] The following describes an image printing method performed using the so-called multi-pass printing process employing the aforementioned processing liquid (Tr), magenta ink (M), light magenta ink (m), and black ink (K). Note that, for simplicity, it is assumed that in S4, the same mask pattern is used for each ink (see...). Figure 6 The printing is performed by performing four scans in a unit area. Note that in this embodiment, printing is completed by performing four scans in a unit area, but the number of scans in a unit area can be set appropriately. Also note that in the following description, performing n print scans in a unit area will be referred to as n-pass print scans (e.g., 4-pass print scans).

[0078] Figure 6 This is a schematic diagram showing an example of a mask pattern to be used in a multi-pass printing process. Figure 7 This is a view used to illustrate the multiple printing process. In this embodiment, through... Figure 6 The four nozzle groups A1 to A4, obtained by dividing each nozzle row 35 along direction A, eject ink in each of the four scans of a unit area. Note that in practice, the printing medium is conveyed to the downstream side along direction A between scans of the printhead unit 3 (described later). However, for illustrative purposes, Figure 6 This shows the printhead unit 3 moving upstream in direction A between scans of the printhead unit 3.

[0079] First, in the first scan (first scan), the printhead unit 3 is scanned with the unit area 80 on the print media P and the nozzle group A1 of the nozzle row 35 positioned relative to each other. The nozzle group A1 ejects ink into the unit area 80 according to the print data generated in S4 and corresponding to each type of ink in the first scan. After the first scan is completed, the print media is transported in the Y direction (transport direction) a distance corresponding to one nozzle group. Then, a second scan (second scan) is performed, and the nozzle group A2 ejects ink into the unit area 80. Thereafter, the transport of the print media P and the ejection of ink from the printhead unit 3 are performed alternately, and nozzle groups A3 and A4 eject ink into the unit area 80 in the third and fourth scans. In this way, multiple passes of printing on the unit area 80 are completed.

[0080] exist Figure 6 In the mask pattern shown, each black pixel indicates a pixel that is allowed to eject ink if ink ejection is determined by quantization data (hereinafter also referred to as a print-allowed pixel). Each white pixel indicates a pixel that is not allowed to eject ink even when ink ejection is determined by quantization data (hereinafter also referred to as a non-print-allowed pixel). Figure 6 Mask patterns, each with a size of 5 pixels × 5 pixels, are shown. By repeatedly applying these mask patterns in directions A and B, allocation processing is performed on all quantized data corresponding to each unit region.

[0081] Figure 6 The number of pixels present in each of the four mask patterns shown is 5 pixels × 5 pixels = 25 pixels. The ratio of the allowed pixels to be ejected in the four 5-pixel × 5-pixel mask patterns is the print tolerance. Print data for applying ink in each print scan can be generated by performing a logical product (AND) operation between a portion of the binary data of each ink (5-pixel × 5-pixel size) and the mask pattern corresponding to each print scan (per pass).

[0082] In the mask patterns corresponding to each scan, three printable pixels are arranged in the mask pattern corresponding to the first scan (nozzle group A1). Therefore, the print tolerance of the mask pattern corresponding to the first scan is approximately 12% (=3 / 25×100). Similarly, the print tolerances of the mask patterns corresponding to the second scan (nozzle group A2), third scan (nozzle group A3), and fourth scan (nozzle group A4) are 36%, 32%, and 12%, respectively. When using these mask patterns, the allocation is performed so that the printhead unit 3 ejects ink across the entire nozzle line. Note that, for simplicity, Figure 6 Each pattern shown is obtained by extracting a portion of the mask pattern, and therefore differs slightly from the printing tolerances mentioned above in some cases.

[0083] <Printing Media and Ink>

[0084] Next, the properties of the printing media and ink to be used in the printing device 100 will be explained.

[0085] (Printing media permeability)

[0086] In this embodiment, the printing apparatus 100 can print images on an impermeable printing medium (where water-soluble ink is impermeable) or on a low-permeability printing medium (where water-soluble ink is almost impermeable). The ink transfer volume obtained by the Bristow process exhibits less than 20 ml / m³. 2Printing media with ink transfer values ​​that are significantly lower than the aforementioned values ​​will be referred to as low-permeability printing media. Additionally, printing media exhibiting ink transfer volumes that are significantly lower than the aforementioned values ​​and are generally difficult to measure will be referred to as non-permeable printing media.

[0087] The Bristow process, a method for evaluating the permeability of ink relative to the printing medium, is described in Japanese TAPPI Pulp Test Method No. 51, "Test Method for Liquid Absorption of Paper and Paperboard". Since this method is explained in many commercially available books, its detailed description will be omitted, and a summary is provided below.

[0088] A predetermined amount of ink is injected into a holding container with a slit of a predetermined size, bringing it into contact with printing media formed in strips and wound around a disk. While the holding container is in a fixed position, the disk rotates and the area (length) of the ink strip transferred to the printing media is measured.

[0089] The transfer volume per unit area (ml / m²) can be calculated based on the area of ​​the ink ribbon. 2 ), and the transfer volume (ml / m 2 This indicates the volume of ink that has penetrated the printing media within a predetermined time. The predetermined time is defined as the transfer time. The transfer time (milliseconds^1 / 2) is equal to the time of contact between the slit and the printing media, and is converted according to the disk speed and the width of the slit opening.

[0090] For general printing coated paper, when measuring the transfer volume of water-based ink using the Bristow process, the transfer volume in a 1-second transfer time is less than 20 ml / m³. 2 Especially when using low-permeability printing media as coating paper, a flow rate of less than 10 ml / m³ is achieved. 2 The value of . When the processing fluid of this embodiment is used on a low-permeability printing medium such as the printing coated paper, more favorable image formation can be performed compared to the case where no processing fluid is used. When using the Bristow process, many inkjet papers exhibit 30 ml / m 2 Or larger transfer volumes, but some of them have a transfer rate of less than 20 ml / m 2 The amount of transfer. Although such a printing medium is inkjet paper, it can also be considered a low-permeability printing medium. That is, the effect can be achieved by applying (described later) the features of this embodiment not only to printing coated paper but also to general printing media, as long as the medium is a low-permeability printing medium.

[0091] Practical examples of impermeable printing media are glass, plastics, and films—that is, products that are not manufactured as printing media for water-based inkjet printing. Examples include products that do not undergo surface treatments for water-based inkjet printing, i.e., products that do not form an absorbent layer, such as products obtained by coating a substrate, such as a non-plastic film or paper, with a plastic coating. Examples of plastics are polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

[0092] Compared to inkjet paper, PVC sheets, to which water-based inks do not penetrate, will be explained below. PVC sheets are flexible sheets manufactured by adding plasticizers to vinyl chloride resin, which is the main material. They possess excellent printing and embossing properties (forming uneven patterns through embossing) in gravure printing, screen printing, and other applications. Because they can achieve a wide variety of expressions through combinations, they are used in many products such as tarpaulins, canvas, and wallpaper. However, because vinyl chloride resin is the main material, water-based inks do not penetrate and overflow onto the sheet surface, resulting in significant image problems and drying issues.

[0093] Practical examples of low-permeability printing media are actual substrates used for offset printing, such as art paper and coated paper.

[0094] In this embodiment, the actual printing substrate will be described. The actual printing substrate is the formal (real) printing paper used in offset printing during the manufacture of products (goods). Paper manufactured using pulp as a material and used directly is uncoated paper, while paper with a smooth surface coated with white pigment is coated paper. In inkjet printing, significant image problems and drying problems caused by ink overflow occur on coated paper. This is achieved by applying approximately 40 g / m³ of sizing agents (e.g., synthetic resins) to limit liquid absorption in the gaps between pulp particles and prevent water-based ink seepage, fillers (e.g., kaolin) to improve opacity, whiteness, and smoothness, and paper reinforcing agents (e.g., starch). 2 The coating is formed by a mixture of paint and ink. The average capillary diameter of the coated paper forms a normal distribution around 0.06 μm, resulting in significant capillary permeation of water (capillary effect). However, the pore volume of the coated paper is much smaller than that of the inkjet paper, resulting in low permeability of water-based inks. Consequently, ink overflows onto the paper surface, leading to noticeable image problems and drying issues.

[0095] (Composition of ink and processing solution)

[0096] The composition of the ink and processing liquid to be used in this embodiment will be described below. In this embodiment, both the colored ink (M, m, and K), which contains pigments as coloring materials, and the processing liquid (Tr), which does not contain pigments but contains components that react with pigments, contain water-soluble organic solvents. In addition, they may also contain water-soluble resin particles (described in detail later), reactants, surfactants, etc.

[0097] Water-soluble organic solvents

[0098] For the sake of wettability and moisture retention of the nozzle surface of the printhead unit 3, the water-soluble organic solvent preferably has a boiling point of 150°C to 300°C. From the viewpoint of its function as an aid to film formation of resin particles, particularly advantageous solvents are ketone compounds such as acetone and cyclohexane, propylene glycol derivatives such as tetraethylene glycol dimethyl ether, and heterocyclic compounds with lactam structures such as N-methylpyrrolidone and 2-pyrrolidone. From the viewpoint of jetting performance, the content of the water-soluble organic solvent is preferably 3 wt% to 30 wt%. Practical examples of water-soluble organic solvents are as follows: Alkyl alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, and tert-butanol; Amides such as dimethylformamide and dimethylacetamide; Ketones and ketols such as acetone and diacetone; Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol. Ethylene glycol. Alkylene glycols containing 2 to 6 carbon atoms, such as propylene glycol, butanediol, triethylene glycol, 1,2,6-hexanetriol, thiodiethylene glycol, hexanediol, and diethylene glycol. Lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate. Glycerin. Lower alkyl ethers of polyols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether. Polyols such as trimethylolpropane and trimethylolethane. N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazoline. The water-soluble organic solvents described above can be used alone or in mixtures.

[0099] Water-soluble resin particles

[0100] In this embodiment, the pigment-containing colored inks (M, m, and K) contain water-soluble resin microparticles to ensure close contact between the printing medium P and the coloring material and improve the scratch resistance (fixation) of the printed image. Since the water-soluble resin microparticles melt due to heat, film formation of the resin microparticles and drying of the solvent contained in the ink are performed by a heater. In this embodiment, "water-soluble resin microparticles" refers to polymer microparticles existing in a dispersed state in water. Practical examples are as follows: Acrylic resin microparticles synthesized by emulsion polymerization of monomers such as alkyl (meth)acrylates or alkylamide (meth)acrylates. Styrene-acrylic resin microparticles synthesized by emulsion polymerization of monomers such as alkyl (meth)acrylates or alkylamide (meth)acrylates and styrene. Polyethylene resin microparticles, polypropylene resin microparticles, polyurethane resin microparticles, and styrene-butadiene resin microparticles. Core-shell resin microparticles with different polymer compositions forming the core and shell portions of the resin microparticles, and resin microparticles obtained by performing emulsion polymerization around acrolein-based microparticles that are pre-synthesized to control particle size, can also be used. In addition, hybrid resin particles obtained by chemically bonding different resin particles such as acrylic resin particles and polyurethane resin particles can be used.

[0101] Furthermore, the aforementioned "polymer microparticles existing in a state dispersed in water" can be in the form of resin microparticles obtained through homopolymerization or various types of copolymerization of monomers having dissociable groups, i.e., so-called self-dispersible resin microparticle dispersions. Examples of dissociable groups are carboxyl groups, sulfonic acid groups, and phosphate groups, and examples of monomers having such dissociable groups are acrylic acid and methacrylic acid. So-called emulsion-dispersed resin microparticle dispersions can also be used. As emulsifiers, materials with anionic charges can be used, regardless of whether the molecular weight is low or high.

[0102] The glass transition temperature (Tg) of the resin microparticles used in the ink of this embodiment is preferably between 40°C and 120°C, and more preferably between 50°C and 110°C. If the Tg is less than 40°C, the resin is soft, and sometimes the effect of improving the scratch resistance of the obtained image cannot be sufficiently obtained. If the Tg is higher than 110°C, the minimum film-forming temperature of the resin emulsion also increases, so the resin applied to the printing medium hardly softens, and this may result in insufficient scratch resistance of the image. From these points of view, since the Tg of the resin microparticles can fall within the range of 40°C to 120°C, it is advantageous to use resin emulsions using methyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate. When water-soluble resin microparticles as described above are used, even when an external force is applied to the printed image by means of a fingernail, slippage occurs, and thus the coefficient of kinetic friction can be effectively reduced. This water-soluble resin microparticle ink will also be referred to as a treatment solution, coating ink, surface coating ink, transparent ink, improving solution, or resin emulsion ink. Tg will be described in detail later.

[0103] Furthermore, it is desirable to use deionized water as the water. The water content (mass%) in the ink is preferably from 10.0% to 90.0% by mass, more preferably from 30.0% to 80.0% by mass, of the total ink mass. Additionally, the water-soluble organic solvent content (mass%) in the ink is preferably from 3.0% to 50.0% by mass, more preferably from 3.0% to 40.0% by mass, of the total ink mass. In order to impart the desired physical properties to the colored ink and water-soluble resin microparticle ink to be used in this embodiment as needed, surfactants, pH adjusters, corrosion inhibitors, preservatives, fungicides, antioxidants, anti-reduction agents, evaporation promoters, chelating agents, and other resins may be appropriately added in addition to the components mentioned above.

[0104] Surfactants

[0105] Because of the use of surfactants, the surface tension of each ink in this embodiment is 20 to 30 dyn / cm. This is because if inks with high surface tension are used on low-permeability / impermeable printing media such as actual substrates or PVC sheets, the ink hardly diffuses on the surface of the printing media, and bubbling occurs more significantly. Fluoro- or silicone-based surfactants are advantageous as surfactants. Even at low concentrations, fluoro- or silicone-based surfactants can reduce the surface tension of the ink, thus improving the wettability of the ink to the printing media. Therefore, even when printing is performed on impermeable printing media, image quality can be improved by suppressing the repulsion of ink on the printing media. Examples of fluorinated and silicone surfactants are Zonyl FSO, Zonyl FSO100, Zonyl FSN, and Zonyl FS100 (manufactured by DuPont); MEGAFACE F-410, MEGAFACE F-493, MEGAFACE F-443, MEGAFACE F-444, and MEGAFACE F-445 (manufactured by DIC); Novec FC-4430 and Novec FC-4432 (manufactured by 3M); FTERGENT 100, FTERGENT 150, FTERGENT 150CH, FTERGENT 250, FTERGENT 400SW, and FTERGENT 501 (manufactured by NEOS); KS508, KP360A, and KP360A (manufactured by Shin-Etsu). (manufactured by Silicone); and FZ-2191, FZ-2123 and 8211ADDITIVE (manufactured by Dow Corning Toray). As the amount of surfactant added increases, the property of reducing the surface tension of the ink becomes stronger, thus improving the wettability and penetration of the ink to the printing medium. Therefore, inks with a surface tension of 30 dyn / cm or less are advantageous for use with low-penetration / impermeable printing media. Furthermore, in order to ensure that the ejection characteristics (ejection volume, ejection speed, etc.) of the ejection nozzles of printheads used for various types of inks are equal, the ink to be used preferably has a surface tension falling within a given range. In the printhead unit 3 of this embodiment, the surface tension preferably falls within the range of ±3 dyn / cm. Note that the surface tension is measured using, for example, a bubble pressure tensiometer model: BP2 manufactured by KRUSS. It is also noted that the measuring device is not limited to this; any device capable of measuring the surface tension of the ink is acceptable.

[0106] In addition, nonionic surfactants can also be used. Even when components that react with the pigment dispersion (e.g., polyvalent metals or acids) are present, nonionic surfactants can stably maintain the dispersion through the dispersion stabilizing effect of the EO chain. Practical examples are polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene glycol esters, polyoxyethylene fatty acid amides, polyoxyethylene fatty acid esters, polyoxyethylene polyoxypropylene glycol, glycerol esters, dehydrated sorbitan esters, sucrose esters, polyoxyethylene ethers of glycerol esters, polyoxyethylene ethers of dehydrated sorbitan esters, polyoxyethylene ethers of sorbitan esters, fatty acid alkanolamides, amine oxides, polyoxyethylene alkylamines, glycerol fatty acid esters, sorbitan anhydride fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and alkyl (poly)ols.

[0107] Coloring materials

[0108] In this embodiment, anionic coloring materials are used in each ink, in addition to the processing liquid. Therefore, the pH of each ink is stable on the alkaline side, and the pH value is between 8.5 and 9.5. From the viewpoint of preventing, for example, impurities from being washed away from the components in contact with the ink, deterioration of the materials forming the components, and a decrease in the solubility of the pigment dispersion resin contained in the ink, the pH of the ink is generally preferably between 7.0 (inclusive) and 10.0 (inclusive). Examples of pH adjusters are organic amines such as diethanolamine and triethanolamine, hydroxides of alkali metals such as sodium hydroxide, lithium hydroxide, and potassium hydroxide, organic acids, and inorganic acids. pH can be measured using, for example, a pH METER Model F-52 manufactured by HORIBA, but the measuring device is not limited, as long as the device can measure the pH of the ink.

[0109] • Treatment fluid

[0110] In this embodiment, a processing liquid (RCT) is used for the purpose of forming an image on a low-permeability or impermeable printing medium. The processing liquid used in this embodiment contains a reactive component that reacts with the pigments contained in the ink, causing the pigments to aggregate or gel. More specifically, this reactive component is one that can disrupt the dispersion stability of the ink when mixed with ink containing pigments stably dispersed or dissolved in an aqueous medium by the action of ionic groups on a printing medium or the like. Since anionic coloring materials are used in this embodiment, the reactants can be broadly categorized into acidic reactants, polyvalent metal reactants, and cationic polymer reactants. In the following description, the processing liquid will also be referred to as a reaction liquid.

[0111] Acidic reactants can be broadly classified into inorganic acids and organic acids. Organic acids will be described in this embodiment, but acidic reactants are not limited to organic acids. Practical examples of organic acids include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, glutaric acid, glutamic acid, fumaric acid, citric acid, tartaric acid, lactic acid, pyrrolidone carboxylic acid, pyranone carboxylic acid, pyrrolic carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, hydroxysuccinic acid, and dihydroxysuccinic acid. As a reference, the organic acid content in the total mass of the components included in the treatment solution preferably ranges from 3.0% by mass to 90.0% by mass, more preferably from 5.0% by mass to 70.0% by mass.

[0112] Favorable examples of multivalent metal reactants are such as Ca 2+ Cu 2+ Ni 2+ Mg 2+ Zn 2+ 、Sr 2+ and Ba 2+ divalent metal ions such as Al 3+ Fe 3+ Cr 3+ and Y 3+ Trivalent metal ions, such as those described above. However, the invention is not limited to these examples. These multivalent metal ions can be contained in the treatment solution by using salts of multivalent metals. A "salt" refers to a metal salt formed from multivalent metal ions as described above and anions bonded to these ions. The salt must be soluble in water. An advantageous example of an anion for forming the salt is Cl. - NO 3- I - ,Br - ClO3 - SO4 2-、 CO3 2- CH3COO - and HCOO - However, the present invention is not limited to these.

[0113] In this embodiment, from the viewpoints of reactivity, colorability, and ease of manipulation, the polyvalent metal ion is more preferably Ca. 2+ Mg 2+ 、Sr 2+ Al 3+ Or Y 3+ And the most preferred option is Ca. 2+ Furthermore, from a safety perspective, methanesulfonic acid is particularly preferred as an anion that forms salts with polyvalent metal ions.

[0114] The cationic polymer reactant is preferably soluble in water. Practical examples of cationic polymers are polyarylamine hydrochloride, polyamine sulfonate, polyethyleneamine hydrochloride, and chitosan acetate. Other examples are copolymers of vinylpyrrolidone and aminoalkylalkyl ester quaternary salts, obtained by cationizing a portion of a nonionic polymeric substance, as well as copolymers of acrylamide and aminomethacrylamide quaternary salts. The treatment solution containing the cationic polymer as a reactive component is preferably colorless, but not necessarily a liquid that exhibits no absorption in the visible range. That is, the treatment solution may also be light-colored and exhibit absorption in the visible range, as long as the liquid does not actually affect the formed image.

[0115] <Adhesion of water vapor from the treatment fluid to the nozzle>

[0116] One characteristic of inkjet printing is its small ink ejection nozzle. This results in smaller ink droplets falling onto the printing medium, allowing for the printing of fine images. However, the small nozzle also makes it prone to defective ink ejection for reasons explained below.

[0117] First, the ejection frequency—the frequency at which the printing element is driven—increases. A smaller volume of ink is ejected from a smaller nozzle, and if the ejection frequency is low, the amount of ink applied to the printing medium per unit time is reduced. On the other hand, the amount of moisture generally increases when the ejection frequency increases. When the amount of moisture in the processing fluid increases, the likelihood of moisture adhering to the vicinity of the color ink ejection nozzle increases. That is, increasing the ejection frequency can increase the incidence of defective ink ejection. Note that the ejection frequency can be reduced by decreasing the carriage scanning rate, but this leads to a decrease in print productivity.

[0118] Furthermore, it is known that as the ejection frequency increases, the airflow generated between the ejection nozzles increases. When the ejection frequency of the color ink ejection nozzles increases, the airflow swirling around the color ink ejection nozzles increases, and this increases the amount of water vapor swirling in the processing liquid. As a result, defective ejection of the color ink may occur.

[0119] Based on the above, the frequency of defective ink ejection caused by moisture in the processing fluid when using a processing fluid can be explained by the relationship between the physical properties of the ink, represented by the mixed viscosity of the processing fluid and the color ink, and the airflow generated between the print head and the printing medium. These two points will be described in detail below.

[0120] (Physical properties of ink)

[0121] In this embodiment, the processing liquid contacts the ink and reduces the flowability of the ink and / or certain ink components on the printing medium. This suppresses ink bleeding and bubbling during image formation. More specifically, reactants contained in the processing liquid (also referred to as ink viscosity-increasing components) contact and chemically react with or physically adsorb the coloring materials and resins that form the ink. This allows for an increase in the overall viscosity of the ink or a localized increase in viscosity by aggregating components such as the coloring materials that form the ink, thereby reducing the flowability of the ink and / or certain ink components.

[0122] As mentioned earlier, a processing fluid is necessary to form images on impermeable media while maintaining high productivity. However, if a small amount of water vapor from the processing fluid mixes with the color ink in the color ink nozzle, defective ejection occurs in the color ink nozzle. This is because when the processing fluid and color ink mix, the dispersion of the pigment contained in the color ink is disrupted, and this increases the viscosity of the color ink in the color ink nozzle.

[0123] Based on the above, the behavior observed when mixing color ink with processing liquid is considered as a physical property of the ink. Mixing viscosity is measured as a method to evaluate the reactive behavior of the ink during mixing.

[0124] Before mixing with the processing liquid, the viscosity of the color ink to be used in this embodiment is preferably 1 to 20 mPa·s. If the ink viscosity is less than 1 mPa·s, it is difficult to form an ink image on an impermeable printing medium, thus resulting in image degradation. On the other hand, if the ink viscosity is greater than 20 mPa·s, ink ejection becomes difficult, and ejection reliability decreases. The ink viscosity is further preferably 2 to 10 mPa·s. Note that the ink viscosity is a value measured by a viscometer (a "RE-80 type viscometer" manufactured by TOKI SANGYO) at 25°C. Note that the measuring device is not limited to the above example, as long as the device can measure ink viscosity. The method for measuring the mixed viscosity of the processing liquid and color ink using the viscometer mentioned above will be described below. The viscometer used in this embodiment is generally referred to as a cone-plate viscometer. First, the color ink is applied to a cup so that the ink spreads and wets the entire cup. Then, the reaction liquid is applied to the center of the cup, the cup is immediately covered with a plate, and the viscosity measurement begins. The measurement is performed for 1 minute by setting the measurement temperature to 25°C and the rotation speed to 5 rpm. Based on these results, a reactivity assessment was performed as an evaluation of viscosity rise behavior by measuring the viscosity after 1 minute and 10 minutes following mixing. Details of the measurement method will be described later.

[0125] (Airflow between the print head and the printing media)

[0126] The airflow (paper-to-paper airflow) between the printhead unit 3 and the printing medium in the printing apparatus 100, which is used as a serial inkjet printer in this embodiment, will now be described.

[0127] Examples of inter-paper airflow in the printing apparatus 100 include the airflow generated when the printhead unit 3 moves (inflow airflow) and the airflow generated by ejecting ink droplets from each ejection nozzle 30 (self-airflow). The inflow airflow is the airflow generated between the printhead unit 3 and the printing medium in the X direction (main scanning direction). The self-airflow is the airflow that flows from the printhead unit 3 to the printing medium, collides with the printing medium, and returns to the printhead unit 3 by reversing the direction of movement. In addition, after the self-airflow collides with the printing medium, the airflow moving towards the printhead overlaps with the inflow airflow, thereby generating a swirling vortex (vortex). It is generally known that when this vortex captures floating water vapor (very small ink droplets in the atmosphere, also simply referred to as water vapor) drifting in the printing apparatus, the floating water vapor continues to advance along the flow of the vortex and adheres to the ejection nozzle surface of the printhead unit 3.

[0128] It is known that the airflow increases as the ink droplet ejection frequency increases. It is also generally known that eddies increase as both the airflow and inflow increase. Therefore, to reduce the amount of water vapor adhering to the surface, it is important to reduce the amount of water vapor generated and to minimize both the airflow and inflow.

[0129] However, reducing the amount of water vapor generated is not always a simple matter, as it may require changes to the nozzle design and the materials used in the ink. Additionally, reducing the jet speed or frequency may effectively decrease the airflow. However, reducing the jet speed may make it difficult to eliminate nozzle clogging caused by evaporating ink. Furthermore, reducing the jet frequency may lead to reduced productivity or product quality degradation, such as decreased color development, as described above. Therefore, it is necessary to reduce eddies while maintaining both productivity and image quality.

[0130] (Positional relationship between the liquid injection nozzle and the color ink injection nozzle)

[0131] The relative position of the nozzle and the adhering water vapor also affects whether the water vapor in the treated liquid is coiled due to eddies and whether it causes defective spraying by adhering to the nozzle surface. Figure 2 The positional relationship between the injection nozzles shown is for illustrative purposes only. In the following description, Figure 2 The magenta ink (M) and light magenta ink (m) shown in the figure are considered as dark ink and light ink, respectively.

[0132] When thick ink (magenta ink (M)) is ejected from nozzle line 35M, which is closest to nozzle line 35Tr for ejecting the treatment liquid, moisture from the treatment liquid adheres between nozzle line 35M for thick ink and nozzle line 35Tr for the treatment liquid, taking into account the location of eddy current generation.

[0133] Note that when moisture adheres between the ink jet line 35M and the processing liquid jet line 35Tr, the moisture typically adheres to the vicinity of these jet lines. Although depending on the state of the vortex, moisture hardly adheres to each jet line itself, and moisture adhesion caused by the vortex often occurs within a range between the jet line and a position approximately 5 mm away from the jet line. Note that the aforementioned distance depends on, for example, the size of the droplets ejected from the jet line, the velocity of the droplets ejected from the jet line, the distance between the jet line and the printing medium, or the scan rate of the printhead. In this embodiment, the evaluation is performed with the ink jet line 35M and the processing liquid jet line 35Tr spaced at least 15 mm or more apart. Therefore, the evaluation is performed in a state where jet lines do not form at the location where processing liquid moisture adheres, and in a state where the jet lines are spaced apart to the extent that defective ejection does not occur due to individual ejection from each jet line.

[0134] On the other hand, when spraying diluted ink (light magenta ink (m)) at a nozzle length of 35m, considering the position of the vortex, the scanning direction in which the processing liquid is sprayed relatively earlier than that of the colored ink ( Figure 2 Processing liquid vapor is generated near the nozzle line 35M (to the left of the image). This is because the evaluation is performed when the nozzle line 35M of the concentrated ink and the nozzle line 35m of the diluted ink are 5mm or less apart. This processing liquid vapor mixes in the nozzle of the concentrated ink nozzle line 35M and disrupts the dispersion of pigment inside the nozzle, thus clogging the nozzle and causing defective spraying. The method for evaluating defective spraying of ink will be described below, followed by an example configuration for suppressing defective spraying of concentrated ink in this nozzle positional relationship.

[0135] <Evaluation Methods>

[0136] • Evaluation of defective spraying

[0137] The printing apparatus 100 of this embodiment includes a configuration for suppressing defective jetting of color ink jets. A method for evaluating the frequency of defective jetting will be described below.

[0138] First, for each of the two types, print five A0-sized solid images (RGB = 0,0,0 and RGB = 255,0,128). Then, print A4-sized solid images (100% load of each color ink) through a single print pass. If there are nozzles causing defective jetting, uninked white lines are formed on the A4-sized print. The number and thickness of these lines are visually evaluated. The evaluation criteria for defective jetting in this embodiment are as follows.

[0139] AA (Defect-Free Spraying)

[0140] ...After solid printing, the lines cannot be visually confirmed.

[0141] A (Several defective jet lines)

[0142] ...After solid printing, several fine lines can be visually identified.

[0143] B (Many defective jet lines)

[0144] ...After solid printing, many thick lines can be visually identified.

[0145] C (Most of them are defective jet lines)

[0146] ...After solid printing, most of the evaluation patterns were not printed.

[0147] • Gray-scale evaluation method

[0148] In this method, control is implemented to relatively reduce the spray ratio of thin ink relative to the spray ratio of thick ink, but this control may abruptly change the color within the same grayscale tone. Therefore, the change in grayscale is evaluated as follows.

[0149] Print an image with concentric grayscale changes and evaluate whether concentric rings are generated by abrupt color changes. That is, evaluate whether concentric rings can be clearly identified visually using the following criteria.

[0150] A (Good grayscale)

[0151] ...At a distance of 30cm, concentric rings cannot be visually confirmed with the naked eye.

[0152] B (the allowable range of gray levels)

[0153] ...Concentric rings can be visually confirmed at a distance of 30cm.

[0154] C (Poor grayscale)

[0155] ...At a distance of 30cm, the thick concentric rings can be clearly visually identified.

[0156] Mixed viscosity evaluation method

[0157] The purpose of this embodiment is to suppress nozzle clogging caused by thickening due to the disruption of pigment dispersion when the processing liquid and water vapor mix in the color ink nozzle. Therefore, the likelihood of nozzle clogging when the ink is mixed can be assessed by measuring the viscosity of the mixture of color ink and processing liquid. For example, when the viscosity does not change after mixing the processing liquid, defective spraying occurs almost never, while when the viscosity increases immediately after mixing the processing liquid, nozzle clogging is likely. Furthermore, even if thickening does not occur immediately after mixing, thickening is sometimes observed when the viscosity is measured after 24 hours. To compare these cases, the following steps are used to measure the mixed viscosity using the aforementioned viscometer to assess whether defective spraying can be suppressed.

[0158] First, collect 0.97 mL of colored ink and apply it to the cone side of the viscometer, ensuring the ink wets the entire cone. Then, apply 0.13 mL of the treatment solution to the center of the cone. Immediately afterward, measure the viscosity at 5 rpm and 25°C for 1 minute. Perform the measurement again immediately after mixing and 10 minutes later.

[0159] By comparing measurements obtained after 1 minute and 10 minutes following mixing, we can assess whether thickening occurs immediately or slowly, or whether almost no reaction occurs.

[0160] It is important to note that when thickening of the mixed viscosity is suppressed, the reactivity with the processing liquid decreases. If the reactivity of the concentrated ink decreases, significant bubbling occurs when performing high-load printing methods on impermeable printing media. To suppress bubbling, it is necessary to limit the amount of ink to be applied to the printing media, but it is difficult to limit the amount of concentrated ink applied for the purpose of printing images with high color rendering. Therefore, in this embodiment, thickening suppression of the mixed viscosity is not performed for concentrated ink, and thickening suppression is performed using dilute ink or colorless ink.

[0161] <Example 1>

[0162] The invention will be further illustrated below by providing examples and comparative examples.

[0163] (Ink composition)

[0164] This example uses a processing liquid that reacts with the pigments contained in the colored inks and accelerates pigment aggregation. Especially when printing images on a liquid-impermeable printing medium (e.g., a resin sheet), the processing liquid and the colored inks mix with each other on the printing medium, thereby promoting thickening caused by pigment aggregation and suppressing bubbling. In the following description, magenta ink and light magenta ink containing pigments will be described as colored inks.

[0165] In this example, starting from the row of nozzles closest to the processing liquid, the nozzles for magenta and light magenta inks are arranged in the order of magenta ink and light magenta ink. Generally, when forming an image with a high color gamut, the ejection frequency of the denser ink tends to increase. Therefore, because this color order is advantageous for the curling caused by eddies, the nozzle rows for denser ink are positioned close to the processing liquid. On the other hand, if, unlike this example, the nozzle rows for thinner ink are positioned close to the processing liquid nozzle rows, then when forming an image with a high ejection frequency and a high color gamut, a large amount of water vapor from the processing liquid adheres to the vicinity of the thinner ink nozzle rows. As a result, defective ejection of the thinner ink may occur significantly. Magenta ink and light magenta ink are described as denser and thinner inks, respectively, but these are merely examples, and the ink colors, etc., are not limited to these examples.

[0166] (Magenta ink)

[0167] (1) Preparation of pigment dispersion

[0168] First, an AB block polymer with an acid value of 300 and a number-average molecular weight of 2500 was prepared using benzyl acrylate and methacrylic acid as raw materials via conventional methods. The polymer was neutralized with an aqueous potassium hydroxide solution and diluted with deionized water to prepare a homogeneous 50% by mass polymer solution. 100 g of this polymer solution, 100 g of CI Pigment Red 122, and 300 g of deionized water were mixed and mechanically stirred for 0.5 hours. The mixture was then treated by passing it through an interaction chamber five times at a liquid pressure of approximately 70 MPa using a microfluidic apparatus. Furthermore, the obtained dispersion was centrifuged (12000 rpm, 20 minutes) to remove non-dispersible matter containing coarse particles, thereby obtaining a magenta dispersion. The obtained magenta dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 5% by mass.

[0169] (2) Preparation of water-soluble resin microparticle dispersion

[0170] First, the following three liquid additives were added dropwise at 70°C under nitrogen atmosphere, stirred by a motor, and polymerized for 5 hours. The liquid additives consisted of a hydrophobic monomer containing 28.5 parts methyl methacrylate, a hydrophilic monomer containing 4.3 parts sodium p-styrene sulfonate and 30 parts water, and a polymerization initiator containing 0.05 parts potassium persulfate and 30 parts water. The resulting solution mixture was used as a water-soluble resin microparticle dispersion.

[0171] (3) Ink making

[0172] Ink was prepared by adding the following components to the aforementioned magenta dispersion at a predetermined concentration. The pigment concentration was adjusted by preparing a 5% by mass pigment ink. Similarly, to achieve a 10% by mass concentration of the obtained water-soluble resin particles in the ink, the following components were mixed, dissolved and dispersed by thorough stirring, and the dispersion was filtered under pressure through a microfilter (manufactured by FUJIFILM) with a pore size of 2.5 μm, thereby preparing the magenta ink. Finally, the ink was adjusted to primarily contain the following components.

[0173] (Example 1 of magenta ink formula)

[0174]

[0175] (Example 1 of a light magenta ink formula)

[0176] By using the aforementioned magenta dispersion and water-soluble resin particle dispersion, the light magenta ink is adjusted so that the mixing ratio of water-soluble resin particles to magenta pigment is equal to the mixing ratio of magenta ink.

[0177]

[0178] (Example 1 of treatment solution formulation)

[0179] The treatment solution was prepared using glutaric acid, an organic acid, one of the reactive components mentioned above. Finally, the treatment solution was adjusted to primarily contain the following components.

[0180]

[0181] (Data Generation)

[0182] This example also features data generation, so data generation will be described in detail below. In this example, a method for suppressing the generation of eddies to prevent defective ink jetting caused by water vapor in the processing liquid will be explained.

[0183] When the inflow or outflow is large, significant vortices are generated, leading to defective jets. Therefore, reducing the outflow is effective in suppressing defective jets. Extensive studies have shown that the effect of the outflow tends to increase at jet frequencies above 10 kHz. Furthermore, the effect of the outflow has been confirmed even at 8 kHz.

[0184] That is, at high carriage speeds, defective ejection is more likely to occur even under the same print load. For example, when a scan is performed at a carriage speed of 60 ips (inches per second), a resolution of 600 dpi, and a print load of 100%, the ejection frequency is 36 kHz. In multi-pass printing, an image is printed in a unit area by performing multiple scans, so the print load of each scan affects the ejection frequency. If the print load of each scan exceeds 22.2%, the effect of eddy currents occurs significantly. Furthermore, when the carriage speed is 30 ips, the effect of eddy currents becomes significant if the print load of each scan exceeds 44.4%. Therefore, it is necessary to consider the relationship between the print load of the thin ink that can be printed per scan and the occurrence of defective ejection.

[0185] In this embodiment, in order to suppress the maximum print load of diluted ink per scan to 20% or less, in Figure 5 The color conversion process shown in the diagram switches the color conversion processing table. More specifically, in the color conversion process, the color conversion processing table is switched based on the number of print scans and the carriage travel speed.

[0186] Figure 8 (A) to Figure 8 Example (C) illustrates a color conversion processing table. In each table, the horizontal axis represents the grayscale values ​​of the image data, and the vertical axis represents the print load for each ink color as the grayscale values ​​change. Grayscale values ​​can be represented in steps of 0 to 100, 0 to 255, etc. Note that the print load on the vertical axis represents the print load for one pass of printing. To distribute the ink jet evenly across each scan when performing, for example, four passes of printing, the print load for each scan is 1 / 4. Note that in the following description, the resolution is 600 dpi under each condition.

[0187] Figure 8 Table 1 shown in (A) is a color conversion processing table as a comparative example. In this table, the print load of light magenta ink is maximum near the halftone and decreases towards the high-tone area. In 4-pass printing scans at a carriage speed of 30 ips, the maximum value D1 of the maximum print load of light magenta ink in Table 1 is set to a value exceeding 40% of the maximum print load per scan. That is, if the color conversion processing using Table 1 is performed under these conditions, significant eddy currents may occur.

[0188] On the other hand, Figure 8 In Table 2 shown in (B), the maximum print load for light magenta ink is reduced compared to the maximum print load in Table 1. To suppress the frequency of defective ink ejection, the maximum print load is reduced to a maximum value D2. In a 4-pass print scan at a carriage speed of 30 ips, the maximum value D2 for light magenta ink in Table 2 is set to 40% or less of the maximum print load per scan. Furthermore, when the print scan is 60 ips, the maximum value D2 is set to 20% or more of the maximum print load per scan.

[0189] exist Figure 8 In Table 3 shown in (C), the maximum print load (maximum value D3) of the light magenta ink is further reduced compared to the maximum print load in Table 2. Additionally, in Table 3, magenta ink is used with a grayscale value (G2) lower than the grayscale value (G1) in Table 2. In 4-pass print scans at a carriage speed of 60 ips, the maximum value D3 is set to 20% or more of the maximum print load per scan, and in 8-pass print scans, it is set to 20% or less of the maximum print load per scan.

[0190] A comparison of Tables 1 and 2 reveals that grayscale is prioritized in Table 1 because of the relatively high print load of thin ink. On the other hand, in Table 2, the maximum print load of thin ink is relatively reduced to suppress defective jetting caused by eddies. Furthermore, in Table 3, the print load of thin ink is further reduced compared to that in Table 2, but grayscale in low-tone areas is ensured by using concentrated ink from lower grayscale values.

[0191] The evaluation results of this embodiment and the comparative examples will be explained below. Comparative Example 1 is an example where the maximum print load per scan exceeds 40% in 4-pass printing scans at a carriage speed of 30 ips, i.e., it is an example using Table 1. On the other hand, Example 1 is an example where the maximum print load per scan is 40% or less in 4-pass printing scans at a carriage speed of 30 ips, i.e., it is an example using Table 2. In addition, Comparative Example 2 and Example 3 are examples showing a comparison between the use of Table 2 and Table 3 in 4-pass printing scans at a carriage speed of 60 ips. Furthermore, Example 3 is an example using Table 1 in 8-pass printing scans at a carriage speed of 60 ips. Note that... Figure 9 The printing scanning methods in these examples and comparisons are shown. Table 1 below summarizes the printing conditions for these examples and comparisons.

[0192] Table 1

[0193]

[0194]

[0195] (Evaluation Results)

[0196] The frequency and grayscale of defective ink ejection were evaluated. The evaluation was performed using the methods described in the <Evaluation Method>. Comparative examples will be explained first. In Comparative Example 1, the maximum print load per scan was high, and the ejection frequency of light magenta ink in the halftone of the grayscale image increased. Since this increased the frequency of defective ink ejection, the grade was C. In Examples 1 and 2, the ejection frequency of light magenta ink decreased, thus the frequency of defective ink ejection could be reduced by suppressing eddies. Note that in Comparative Example 2, the frequency of defective ink ejection could be reduced because the print load of light magenta ink was reduced. On the other hand, grayscale decreased in Comparative Example 2. This is because the increased carriage speed increased the limitation on the print load of thin ink, so grayscale was separated before the use of thick ink. In contrast, in Example 2, the printing of magenta ink started from the low-tone stage, thus ensuring grayscale. Furthermore, in Example 3, the number of print scans was high, so when using the same table, the print load per scan was significantly reduced compared to the other examples. Therefore, in Example 3, by using Table 1, which serves as a color conversion processing table for prioritizing grayscale, good results can be obtained in terms of both the frequency of defective spraying and grayscale. Table 2 below summarizes these results.

[0197] Table 2

[0198]

[0199]

[0200] Even with a high number of print scans, switching color conversion processing tables can improve image quality while ensuring reliability. For example, when performing a total of 8 print scans using Tables 1 and 2 above, Table 2 is more effective at reducing the frequency of defective jets, but Table 1 is superior in terms of grayscale. Therefore, when performing a total of 8 print scans, it is beneficial to switch to Table 1, which prioritizes grayscale, instead of Table 2, which prioritizes the frequency of defective jets. For example, when using Table 1 at a carriage speed of 30 ips in 4 print scans, the maximum print load per scan exceeds 40%. However, when the maximum print load per scan is 40% or less in 8 print scans, using Table 1 can suppress defective jets while maintaining good grayscale.

[0201] (Method for selecting a color conversion processing table)

[0202] As mentioned above, by using an appropriate color conversion processing table according to the printing conditions, defective inkjet printing can be suppressed and grayscale can be ensured. The process of selecting a color conversion processing table will be explained below. Figure 10A and Figure 10B This is a flowchart illustrating an example of CPU 301 processing. These flowcharts are implemented by CPU 301 reading programs stored in ROM 302 into RAM 303 and executing those programs. For example, this is performed when the settings of the printing device 100 change, or when a print command is received. Figure 5 These flowcharts can be executed before the flowcharts shown in the diagram.

[0203] In S11, CPU 301 acquires the printing conditions. For example, CPU 301 reads the printing conditions stored in the storage area of ​​the printing device 100. Examples of printing conditions are carriage speed, resolution, and the number of scans (passes) per unit area in multi-pass printing.

[0204] In S12, the CPU 301 selects a color conversion processing table based on the acquired printing conditions. For example, when performing a printing operation under the acquired printing conditions, the CPU 301 selects a color conversion processing table such that the ejection frequency of the light magenta ink nozzle 30 is equal to or less than a threshold. The threshold can be set to a value in the range of, for example, 8kHz and 10kHz. For example, when the carriage speed is relatively low, the resolution is relatively low, and the number of print passes is relatively high, even if a color conversion processing table with a relatively high maximum print load for light magenta ink is selected, the ejection frequency may still become equal to or less than the threshold. In this case, printing can be performed by selecting, for example, Table 1 above to maintain good grayscale. On the other hand, when the carriage speed is relatively high, the resolution is relatively high, and the number of print passes is relatively low, the ejection frequency often increases, so defective ejection can be suppressed by selecting, for example, Table 2 or Table 3 above.

[0205] Figure 10B This is a flowchart illustrating an actual processing example of S12. Figure 10B The process is shown when one of Tables 1 to 3 above is selected based on the printing conditions. Note that, for illustrative purposes, it is assumed that the carriage speed is selected from 60 ips and 30 ips, the number of strokes is selected from 4 and 8, and the resolution is constant at 600 dips.

[0206] In S120, CPU 301 confirms the type of printing media. If the printing media is impermeable or low-permeability, it proceeds to S121; otherwise, it proceeds to S125 and selects Table 1. CPU 301 obtains information about the type of printing media set by the user, etc., and performs a determination based on the obtained information. If the printing media is neither impermeable nor low-permeability, processing fluid is not required, and this eliminates the need to limit the ink jetting frequency to suppress the adhesion of processing fluid moisture. Therefore, Table 1, which assigns priority to grayscale, is selected.

[0207] In S121, based on the information obtained in S11, CPU 301 proceeds to S122 if the carriage speed is 30 ips, and proceeds to S124 if the carriage speed is 60 ips. In S122, based on the information obtained in S11, CPU 301 proceeds to S123 and selects Table 2 if the number of passes is 4, and proceeds to S125 and selects Table 1 if the number of passes is 8. That is, when the carriage speed is 30 ips and the number of passes is 4, if Table 1 is used as described above, the maximum print load per scan exceeds 40%, and therefore the maximum ejection frequency exceeds 8 kHz. Therefore, the ejection frequency is limited by selecting Table 2. On the other hand, when the carriage speed is 30 ips and the number of passes is 8, even when using Table 1, the maximum ejection frequency does not exceed 8 kHz, so grayscale is ensured by selecting Table 1. Similarly, in S124, based on the information obtained in S11, CPU 301 proceeds to S126 and selects Table 3 if the number of times is 4, and proceeds to S125 and selects Table 1 if the number of times is 8.

[0208] By selecting a table based on the above processing example, printhead unit 3 is controlled to reduce the maximum print load of light magenta ink when the number of passes is low, thereby limiting the ejection frequency when the number of passes is low. Additionally, by selecting a table based on the above processing example, printhead unit 3 is controlled to reduce the maximum print load of light magenta ink when the carriage speed is high, thereby limiting the ejection frequency when the number of passes is low. That is, in this embodiment, CPU 301 controls printhead unit 3 to change the maximum print load of thin ink according to printing conditions such as carriage speed, number of passes, or resolution, thereby changing the degree of control over the ejection frequency of thin ink. From another perspective, this embodiment limits the ejection frequency of thin ink by changing the ejection ratio of thin ink to thick ink according to printing conditions. This makes it possible to suppress the adhesion of processing liquid moisture caused by thin ink.

[0209] When the carriage speed is 60 ips, Table 3 is selected at stroke 4, and Table 1 is selected at stroke 8. Table 3 is set to ensure that the amount of light magenta ink applied is greater than that when Table 1 is selected in grayscale regions where the maximum print load of light magenta ink is relatively small and therefore the amount of light magenta ink applied is limited. This ensures grayscale even when the limitation on the jetting frequency of light magenta ink is relatively large.

[0210] Figure 11 This is a flowchart illustrating another example of the actual processing of S12. Figure 11 The following processing example is shown: In the printing device 100, the user can select a grayscale priority mode, which prioritizes grayscale values, as the printing mode, and a defective jet suppression priority mode, which prioritizes the suppression of defective jets, as the printing mode.

[0211] In S131, CPU 301 checks, based on the information obtained in S11, whether the ejection frequency of the light magenta ink exceeds a threshold if Table 1 is selected. If the ejection frequency exceeds the threshold, CPU 301 proceeds to S132; otherwise, it proceeds to S134 and selects Table 1. Based on the obtained carriage speed, resolution, and number of strokes, when the maximum print load of the light magenta ink is the maximum value D1, CPU 301 checks whether the maximum ejection frequency exceeds a threshold (e.g., whether the maximum ejection frequency exceeds 10 kHz or is less than 10 kHz or lower). More specifically, the ejection frequency can be calculated as follows:

[0212] Ejection frequency (kHz) = carriage speed (ips) × resolution (dpi) × maximum print load (%) / (number of prints × 1000)

[0213] Therefore, CPU 301 checks the ejection frequency based on this formula. If it is determined that the ejection frequency does not exceed the threshold, then defective ejection of light magenta ink will hardly occur even when using Table 1, so CPU 301 selects Table 1.

[0214] In S132, CPU 301 checks the printing mode. If the printing mode is a grayscale priority mode, CPU 301 proceeds to S134 and selects Table 1; if the printing mode is a defective jet suppression priority mode, it proceeds to S133 and selects the defective jet suppression priority mode. In this process, if there is a possibility of defective jetting, the user can intentionally choose whether to prioritize grayscale or suppressing defective jetting.

[0215] Note that in this embodiment, the ink ejection frequency is limited by switching the color conversion processing table, but another approach can also be used. For example, multiple arithmetic expressions defining the relationship between grayscale values ​​and print load can be prepared, and the ink ejection frequency can be limited by calculating the print load based on the arithmetic expressions corresponding to the printing conditions.

[0216] Furthermore, the positional relationship between the concentrated ink jet nozzles and the diluted ink jet nozzles only needs to be as follows: based on their relationship with the reaction liquid jet nozzles, the concentrated ink jet nozzles are closer to the reaction liquid jet nozzles than the diluted ink jet nozzles. Therefore, the ink color is not limited to the relationship that concentrated ink is magenta and diluted ink is light magenta.

[0217] When the dilute ink jet nozzle is closer to the reaction liquid jet nozzle than the concentrated ink jet nozzle, changes in reactivity and the frequency of defective jetting need to be considered. This will be explained in Example 2 below.

[0218] <Example 2>

[0219] In this example, the case of considering another jet row in addition to the ink jet row closest to the processing liquid and the adjacent jet rows will be explained as the relationship between the position of the jet row and the colored ink. More specifically, the jet rows of magenta and light magenta inks have been described in Example 1, but in this embodiment, the case of considering the jet row of black ink will also be explained. Note that this example will be explained by considering black ink, but the ink only needs to have a relatively high pigment concentration, so yellow ink or another color ink can also be used.

[0220] (Ink composition)

[0221] In this example, the inspection is performed using the ink from Example 1 as magenta ink and processing liquid. Light magenta ink and black ink will be described below.

[0222] (Black ink)

[0223] (1) Preparation of pigment dispersion

[0224] First, anionic polymer P-1 [a styrene / butyl acrylate / acrylic acid copolymer with an acid value of 202 and a weight-average molecular weight of 6500 (polymerization ratio (by weight) = 30 / 40 / 30)] was prepared. Anionic polymer P-1 was neutralized with an aqueous potassium hydroxide solution and diluted with deionized water to prepare a homogeneous 10% by mass polymer solution.

[0225] 600 g of the polymer solution, 100 g of carbon black, and 300 g of deionized water were mixed, and the mixture was mechanically stirred for a predetermined time and then centrifuged to remove non-dispersible matter containing coarse particles, thereby obtaining a black dispersion. The obtained black dispersion had a pigment concentration of 10% by mass.

[0226] (2) Ink making

[0227] Ink was prepared by using the aforementioned black dispersion and water-soluble resin microparticle dispersion, and adding the following components to them at a predetermined concentration. The pigment concentration was adjusted by preparing a 5% by mass pigment ink. Similarly, to achieve a 10% by mass concentration of the obtained water-soluble resin microparticles in the ink, the following components were mixed, dissolved and dispersed by thorough stirring, and the dispersion was filtered under pressure through a microfilter (manufactured by FUJIFILM) with a pore size of 2.5 μm, thereby preparing the black ink. Finally, the ink was adjusted to primarily contain the following components.

[0228] (Example 1 of black ink formula)

[0229]

[0230] (Light red ink)

[0231] In this example, a nonionic activator is added to suppress mixing viscosity. This is to suppress defective spraying caused by the high-frequency spraying of adjacent black inks. More specifically, the addition of a nonionic activator can improve the dispersion stability of the magenta pigment and reduce the impact of dispersion-damaging materials. Extensive studies have shown that the addition amounts in the following formulations have an effect on suppressing defective spraying. As a comparative example, Formulation Example 3 shows a highly reactive light magenta ink formulation. This is an example of adding water-soluble resin particles at a high concentration.

[0232] (Example 2 of a light magenta ink formula)

[0233]

[0234]

[0235] (Example 3 of a light magenta ink formula)

[0236]

[0237] (Evaluation of the physical properties of ink)

[0238] The mixed viscosities of the three types of inks are shown in Table 3 below. Note that "before mixing" in this table refers to the viscosity of each light magenta ink formulation before mixing with the treatment solution. The unit is mPa·s.

[0239] Table 3

[0240]

[0241] Table 3 shows that, based on the differences between the light magenta ink formulations, the evaluation results can be categorized into cases where the reaction occurs immediately, cases where the reaction occurs slowly, and cases where almost no reaction occurs.

[0242] In Formulation Example 1, the viscosity increases significantly within 10 minutes, indicating slow thickening. In Formulation Example 3, thickening is noticeable within 1 minute, indicating an immediate reaction. In Formulation Example 2, almost no thickening occurs until 10 minutes, meaning the reaction is very low. In this example, the variation in reactivity and the frequency of defective spraying will be illustrated by switching between the three types of light magenta inks mentioned above.

[0243] (Head structure)

[0244] In this example, an image is formed on a printing medium by ejecting the aforementioned ink from the ejection nozzle via a head. In this case, the positional relationship between the processing liquid and each color ink significantly affects the frequency of defective ejections. In this example, the processing liquid and each color ink are arranged in... Figure 2 The location shown in the image.

[0245] In this example, a magenta ink with relatively high reactivity is used in the row of nozzles closest to the processing liquid. Typically, in many cases, highly reactive color inks are placed further away from the reaction liquid. As a comparative example, the frequency of defective sprays is compared based on the levels shown in Table 4 below. Note that in Table 4, "Color Ink Spray No. 1" is the nozzle closest to the processing liquid spray nozzle, and "Color Ink Spray No. 2" and "Color Ink Spray No. 3" are arranged in this order, gradually spaced apart from the reaction liquid spray nozzle.

[0246] Table 4

[0247]

[0248]

[0249] (Printing method)

[0250] In this example, an image is formed in each predetermined area through four print scans using a multi-pass printing process. Additionally, the carriage speed is 30 ips, and Table 2 shown in Example 1 is used for color conversion processing, etc.

[0251] (result)

[0252] Table 5 below summarizes the nozzle arrangement and the corresponding frequency of defective sprays according to this example.

[0253] Table 5

[0254] Frequency of defective spraying Example 4 AA Comparative Example 3 A Comparative Example 4 B Comparative Example 5 C Comparative Example 6 C Comparative Example 7 C

[0255] Table 5 shows the good results achieved by the nozzle arrangement in this example. Note that in the comparative example, defective spraying was significant at the location of the color ink nozzle 2 used for spraying color ink 3. As assumed based on the positional relationship with the nozzles causing defective spraying, the curling of the processing liquid due to eddies is the cause of the defective spraying. On the other hand, this example uses a low-reactivity ink as color ink 2 (light magenta ink) and is able to suppress defective spraying of color ink 2 (light magenta ink) caused by spraying color ink 3 (black ink). That is, the color of the ink used in this example is not limited. Concentrated inks generally have high reactivity. The purpose of this example is to arrange concentrated ink in color ink nozzles 1 and 3 and to arrange dilute ink in color ink nozzle 2. Another purpose of this example is to prevent concentrated inks from being arranged adjacent to each other. Table 6 shows an example of the arrangement of concentrated and dilute inks that can suppress defective spraying. Note that the concentrated inks in Table 6 are cyan, magenta, yellow, and black inks, and generally have a pigment concentration of 1% or greater. The diluted inks in Table 6 are light cyan, light magenta, gray, and light gray inks, and typically have a pigment concentration of less than 1%. Note that, as will be described in detail in other examples, diluted inks include inks without pigment.

[0256] Table 6

[0257]

[0258] <Other Examples>

[0259] In Example 1, based on the relationship between the processing liquid ejection nozzle and the color ink ejection nozzle, the ejection frequency of the thin ink is limited to suppress defective ejection of the color ink, and the selection of the color conversion processing table to ensure grayscale is illustrated. More specifically, the dense ink is placed in the color ink ejection nozzle row close to the processing liquid ejection nozzle, and the thin ink is placed further away, thereby limiting the ejection frequency of the thin ink and performing color conversion processing on the dense ink to ensure grayscale.

[0260] Example 2 illustrates the relationship between the reactivity of the reaction solution and the nozzle position as the amount of colored ink increases. More specifically, it illustrates the case where the three colored inks are adjacent to each other. More specifically, it illustrates the limitation on the spraying frequency of the ink placed at the center of the three inks and the suppression of defective spraying through reactivity control.

[0261] This example illustrates the case where the ink placed in the center is a light magenta ink, but this ink is not limited to light magenta, and the same effect can be achieved with inks having limited reactivity. Therefore, this example will illustrate the case where a transparent ink containing no pigment or a very small amount of pigment is placed in the center. For ease of explanation, a pigment-free ink will be described in the formulation example.

[0262] The advantage of this approach is that it makes it easier to suppress defective spraying, eliminates concerns about the aforementioned gray levels, and offers greater flexibility in using both concentrated and diluted inks. The formulation for transparent ink is as follows.

[0263] (Example 1 of a transparent ink formulation)

[0264]

[0265] Note that Formula Example 1 is used for each of the magenta ink, black ink, and processing liquid. Also note that, regarding the relationship between the nozzle row and ink color, the colored ink 2 in this example is replaced with the transparent ink in Table 4 above. Furthermore, the same printing method as described in Examples 1 and 2 is used as the printing method.

[0266] When evaluating the frequency of defective jetting in this example, the result was AA. Based on this result, and the results of Examples 1 and 2 above, it is confirmed that even when using transparent ink, an effect equal to or greater than that of the examples above can be obtained. Furthermore, Example 2 illustrates the case where three colored ink jet lines are close to each other. The case where four or more colored ink jet lines are adjacent to each other will be described below.

[0267] It is difficult to limit the ejection frequency of dense ink. This is because dense ink is used for the purpose of increasing print load and improving color development. That is, in order to limit the ejection frequency, it is difficult to arrange dense ink nozzles next to each other. However, by limiting the adjacency between dense ink nozzles, four or more nozzle rows can be arranged close to each other. This allows for a reduction in carriage size.

[0268] In this embodiment as described above, selecting a maximum print load of light magenta ink that is less than the maximum print load in Table 2 of Table 1 is equivalent to selecting a case where the restriction on the ejection frequency of light magenta ink is greater than that of grayscale. In this embodiment, the printing apparatus 100 controls the printing of the printhead unit 3 according to the printing conditions to change the restriction on the ejection frequency of light magenta ink corresponding to a specific ejection nozzle. Therefore, according to this embodiment, it is possible to prevent the ejection frequency of light magenta ink from exceeding a predetermined value, for example, a value of 8 kHz to 10 kHz that may be affected by airflow, and to suppress defective ink ejection caused by the adhesion of processing liquid moisture. Furthermore, this configuration does not require any moisture extraction mechanism, etc., so defective ink ejection can be suppressed with a simple configuration.

[0269] Furthermore, this embodiment does not limit the ejection frequency of magenta ink (dense ink) with a relatively high pigment concentration, but limits the ejection frequency of light magenta ink (dilute ink) with a relatively low pigment concentration. This allows for the suppression of defective ejections caused by the ejection of dilute ink while ensuring the color development of dense ink. Additionally, in this example, the ejection nozzle line 35M of the magenta ink is closer to the ejection nozzle line 35Tr of the processing liquid than the ejection nozzle line 35m of the light magenta ink. Therefore, in the area between ejection nozzle lines 35Tr and 35M where there are no ejection nozzle lines, moisture adhesion occurs due to the airflow generated by the ink ejection from ejection nozzle line 35M. Therefore, defective ejections caused by the ejection of dense ink can be suppressed without particularly limiting the ejection frequency of the dense ink ejection nozzle line.

[0270] <Other Embodiments>

[0271] The embodiments described above are illustrated using a printing apparatus that employs inkjet printing. However, the printing apparatus can also be, for example, a single-function printer with only printing capabilities or a multi-function printer with multiple functions such as printing, faxing, and scanning. Additionally, the printing apparatus can be a manufacturing apparatus for producing, for example, color filters, electronic devices, optical devices, or microstructures using a predetermined printing process.

[0272] One or more embodiments of the present invention can also be implemented by a computer that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transient computer-readable storage medium") to perform the functions of one or more embodiments described above and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more embodiments described above, and by a method executed by a computer of a system or device, for example, by reading and executing computer-executable instructions from a storage medium to perform the functions of one or more embodiments described above and / or controlling one or more circuits to perform the functions of one or more embodiments described above. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include a network of individual computers or individual processors to read and execute the computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or storage medium. The storage medium may include, for example, a hard disk, random access memory (RAM), read-only memory (ROM), storage devices for distributed computing systems, optical discs (such as CDs, DVDs, or Blu-ray discs). TMOne or more of the following: flash memory devices, memory cards, etc.

[0273] Other embodiments

[0274] The embodiments of the present invention can also be implemented by providing software (programs) that perform the functions of the above embodiments to a system or device via a network or various storage media, and the computer or central processing unit (CPU) or microprocessor unit (MPU) of the system or device reads out and executes the program.

[0275] <Additional>

[0276] The embodiments mentioned above disclose at least a printing apparatus, a control method for the printing apparatus, a print head, and a printing system.

[0277] (Project 1)

[0278] A printing apparatus, comprising:

[0279] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, a plurality of printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction. In the first element row, a plurality of printing elements for applying a first ink are arranged in a first direction. In the second element row, a plurality of printing elements for applying a second ink are arranged in a first direction. The reactivity of the second ink to the reaction liquid is lower than that of the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0280] The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium; and

[0281] The print control unit is configured to control the printing operation of the print unit such that the ratio of the number of pixels allowed to eject the second ink to the number of pixels in a predetermined area on the print medium does not exceed a threshold.

[0282] (Project 2)

[0283] According to the apparatus of Project 1, the second ink is an ink having the same hue as the first ink and a lower coloring material concentration than the first ink.

[0284] (Project 3)

[0285] The apparatus according to item 1 or 2 further includes a determining unit configured to determine the amount of a first ink and a second ink applied based on input image data.

[0286] The print control unit controls the printing operation based on the applied amount determined by the determining unit.

[0287] (Project 4)

[0288] According to the apparatus described in Project 3, the determining unit determines the amount of first ink and the amount of second ink applied based on the printing conditions of the printing operation.

[0289] (Project 5)

[0290] According to the apparatus described in Project 4, the determining unit determines the amount of second ink applied such that the amount applied does not exceed a threshold determined for each printing condition.

[0291] (Project 6)

[0292] According to the apparatus described in Project 5, wherein...

[0293] The printing unit completes the printing of an image by scanning a unit area on the printing medium multiple times.

[0294] The printing conditions include the number of scans in the unit area, and

[0295] The threshold determined for printing conditions where the number of scans is the first number of scans is greater than the threshold determined for printing conditions where the number of scans is the second number of scans, and the second number of scans is less than the first number of scans.

[0296] (Project 7)

[0297] According to the apparatus described in Project 5, wherein...

[0298] Printing conditions include the scanning rate of the printing unit, and

[0299] The threshold determined for printing conditions where the scan rate is the first scan rate is greater than the threshold determined for printing conditions where the scan rate is the second scan rate, where the second scan rate is higher than the first scan rate.

[0300] (Project 8)

[0301] According to the apparatus described in Project 3, wherein...

[0302] The print control unit executes a first control and a second control based on the printing conditions of the printing operation. In the first control, the threshold is a first value; in the second control, the threshold is a second value smaller than the first value.

[0303] In the second control, the amount of the first ink applied in the grayscale region where the amount of the second ink applied is limited is greater than the amount of the first ink applied in the grayscale region where the amount of the second ink applied is limited in the first control.

[0304] (Project 9)

[0305] The apparatus according to any one of items 1 to 8, wherein the printing control unit causes the printing unit to apply the reaction liquid to a printing medium that satisfies the conditions regarding the permeability of the water-based ink.

[0306] (Project 10)

[0307] According to the apparatus described in Project 9, the condition regarding the permeability of the water-based ink is that the ink transfer amount obtained through the Bristow process is less than 20 ml / m³. 2 The value of .

[0308] (Project 11)

[0309] The apparatus according to any one of items 1 to 10, wherein the distance between the first element row and the reaction liquid element row in the second direction is greater than the distance between the first element row and the second element row in the second direction.

[0310] (Project 12)

[0311] The apparatus according to any one of items 1 to 11, wherein the printing unit includes a first printhead having rows of reaction liquid elements and a second printhead having rows of first elements and rows of second elements.

[0312] (Project 13)

[0313] According to the apparatus of item 12, the second printhead further includes a third element row in which a plurality of printing elements for applying a third ink having a hue different from that of the first ink and the second ink are arranged in a first direction.

[0314] (Project 14)

[0315] According to the apparatus described in item 13, wherein...

[0316] In the second direction, the distance between the third element row and the reaction liquid element row is greater than the distance between the second element row and the reaction liquid element row, and the distance between the first element row and the reaction liquid element row is greater than the distance between the second element row and the third element row.

[0317] The reactivity between the third ink and the reaction solution is higher than that between the second ink and the reaction solution.

[0318] (Project 15)

[0319] The apparatus according to any one of items 1 to 14, wherein the reactivity between the ink and the reaction liquid is the degree to which the viscosity of the ink increases after the ink and the reaction liquid are mixed.

[0320] (Project 16)

[0321] The apparatus according to any one of items 1 to 15, wherein the reaction liquid contains a reactive component that causes the coloring material in the ink to aggregate or gel.

[0322] (Project 17)

[0323] The apparatus according to any one of items 1 to 16, wherein,

[0324] The first and second inks contain pigments as coloring materials, and

[0325] The pigment concentration in the first ink is higher than that in the second ink.

[0326] (Project 18)

[0327] The apparatus according to any one of items 1 to 17, wherein,

[0328] The first ink contains pigment, and

[0329] The second ink does not contain pigment.

[0330] (Project 19)

[0331] According to the apparatus of Project 4, the determining unit determines the amount of the first ink and the amount of the second ink by switching a table that shows the ratio of the grayscale values ​​relative to the second ink.

[0332] (Project 20)

[0333] The apparatus according to any one of items 1 to 19, wherein the printing control unit controls the printing operation such that the frequency of the printing element used to apply the second ink to the predetermined area is not more than 10 kHz.

[0334] (Project 21)

[0335] A method for controlling a printing apparatus, the printing apparatus comprising:

[0336] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with a coloring material in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in a first direction. In the second element row, multiple printing elements for applying a second ink are arranged in a first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction. The method includes:

[0337] Scan the printing unit in the second direction relative to the printing medium; and

[0338] The printing operation of the printing unit is controlled such that the ratio of the number of pixels allowed to eject second ink to the number of pixels in a predetermined area on the printing medium does not exceed a threshold.

[0339] (Project 22)

[0340] A printhead includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, a plurality of printing elements for applying a reaction liquid containing components that react with a coloring material in ink are arranged in a first direction. In the first element row, a plurality of printing elements for applying a first ink are arranged in the first direction. In the second element row, a plurality of printing elements for applying a second ink are arranged in the first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0341] (Project 23)

[0342] According to the printhead described in Item 22, the second ink has the same hue as the first ink, and the coloring material concentration of the second ink is lower than that of the first ink.

[0343] (Project 24)

[0344] A printing system, comprising:

[0345] Printing apparatus, including

[0346] A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in the first direction. In the second element row, multiple printing elements for applying a second ink are arranged in the first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction.

[0347] The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium, and

[0348] A print control unit is configured to control the printing operation of the print unit; and

[0349] An information processing apparatus includes a determining unit configured to determine the amount of a second ink applied based on input image data, such that the amount of the second ink sprayed per unit time does not exceed a threshold.

[0350] The printing control unit controls the printing of the printing unit based on the applied amount determined by the determining unit.

[0351] While the invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to include all such modifications and equivalent structures and functions.

Claims

1. A printing apparatus, comprising: A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with a coloring material in the ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in a first direction. In the second element row, multiple printing elements for applying a second ink are arranged in a first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction. The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium; as well as The print control unit is configured to control the printing operation of the print unit based on printing conditions, such that the ejection frequency of the second ink does not exceed a threshold, the printing conditions including the scanning rate of the print unit and the number of scans per unit area of ​​the print medium.

2. The apparatus according to claim 1, wherein, The second ink is an ink with the same hue as the first ink but a lower concentration of coloring material than the first ink.

3. The apparatus according to claim 1 or 2, wherein, The print control unit determines the amount of first ink and second ink to be applied based on the input image data, and controls the printing operation based on the determined amount of ink to be applied.

4. The apparatus according to claim 1, wherein, The print control unit controls the printing operation so that the ejection frequency of the second ink does not exceed a threshold, regardless of whether the scan rate is the first scan rate or a second scan rate that is different from the first scan rate.

5. The apparatus according to claim 3, wherein, The printing control unit selects one of several tables relating to the amount applied to each of the first and second inks.

6. The apparatus according to claim 1, wherein, When the number of scans is the same as the first scan, the threshold is the first value. When the number of scans is less than the number of scans in the first scan, the threshold is a second value, and The first value is higher than the second value.

7. The apparatus according to claim 1, wherein, When the scan rate is the first scan rate, the threshold is a first value. When the scan rate is a second scan rate that is higher than the first scan rate, the threshold is a second value, and The first value is higher than the second value.

8. The apparatus according to claim 3, wherein, The print control unit executes first control and second control based on the printing conditions of the printing operation. In the first control, the threshold is a first value; in the second control, the threshold is a second value lower than the first value. In the second control, the amount of the first ink applied in the grayscale region where the amount of the second ink applied is limited is greater than the amount of the first ink applied in the grayscale region where the amount of the second ink applied is limited in the first control.

9. The apparatus according to claim 1 or 2, wherein, The print control unit causes the print unit to apply the reaction liquid to a print medium that meets the conditions for the permeability of water-based ink.

10. The apparatus according to claim 9, wherein, The conditions for the permeability of water-based inks are that the ink transfer rate obtained through the Bristow process is less than 20 ml / m³. 2 The value of .

11. The apparatus according to claim 1 or 2, wherein, The distance between the first element row and the reaction liquid element row in the second direction is longer than the distance between the first element row and the second element row in the second direction.

12. The apparatus according to claim 1 or 2, wherein, The printing unit includes a first printhead having rows of reaction liquid elements and a second printhead having rows of first and second elements.

13. The apparatus according to claim 12, wherein, The second printhead also includes a third element row in which multiple printing elements for applying a third ink having a hue different from that of the first ink and the second ink are arranged in a first direction.

14. The apparatus according to claim 13, wherein, In the second direction, the distance between the third element row and the reaction liquid element row is longer than the distance between the second element row and the reaction liquid element row, and the distance between the first element row and the reaction liquid element row is longer than the distance between the second element row and the third element row. The reactivity between the third ink and the reaction solution is higher than that between the second ink and the reaction solution.

15. The apparatus according to claim 1 or 2, wherein, The reactivity between the ink and the reaction liquid is the degree to which the viscosity of the ink increases after the ink and the reaction liquid are mixed.

16. The apparatus according to claim 1 or 2, wherein, The reaction solution contains reactive components that cause the coloring materials in the ink to aggregate or gel.

17. The apparatus according to claim 1 or 2, wherein, The first and second inks contain pigments as coloring materials, and The pigment concentration in the first ink is higher than that in the second ink.

18. The apparatus according to claim 1 or 2, wherein, The first ink contains pigment, and The second ink does not contain pigment.

19. The apparatus according to claim 3, wherein, The print control unit determines the application amount of the first ink and the second ink by switching tables. Each table associates the print load with the grayscale value of the second ink. Print load is the ratio of the number of pixels to which the second ink is allowed to be ejected to to the number of pixels in a predetermined area on the printing medium.

20. The apparatus according to claim 1 or 2, wherein, The print control unit controls the printing operation so that the ejection frequency of the second ink does not exceed 10 kHz.

21. A method for controlling a printing apparatus, the printing apparatus comprising: A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with a coloring material in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in a first direction. In the second element row, multiple printing elements for applying a second ink are arranged in a first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction. The method includes: Scan the printing unit in the second direction relative to the printing medium; and The printing operation of the printing unit is controlled based on printing conditions, so that the ejection frequency of the second ink does not exceed a threshold. The printing conditions include the scanning rate of the printing unit and the number of scans per unit area of ​​the printing medium.

22. A printing system, comprising: Printing apparatus, including A printing unit includes a row of reaction liquid elements, a first element row, and a second element row. In the row of reaction liquid elements, multiple printing elements for applying a reaction liquid containing components that react with coloring materials in ink are arranged in a first direction. In the first element row, multiple printing elements for applying a first ink are arranged in the first direction. In the second element row, multiple printing elements for applying a second ink are arranged in the first direction. The second ink has a lower reactivity to the reaction liquid than the first ink. The row of reaction liquid elements, the first element row, and the second element row are arranged sequentially in a second direction perpendicular to the first direction. The scanning unit is configured to scan the printing unit in a second direction relative to the printing medium, and The print control unit is configured to control the printing operation of the print unit; as well as An information processing apparatus includes a determining unit configured to determine the amount of second ink applied based on input image data and printing conditions, such that the ejection frequency of the second ink does not exceed a threshold, the printing conditions including the scanning rate of the printing unit and the number of scans per unit area of ​​the printing medium. The printing control unit controls the printing of the printing unit based on the applied amount determined by the determining unit.

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