Recording device and recording method

Abstract

In a printing apparatus having a drying device that dries ink ejected onto a printing medium using a collision jet, image unevenness is suppressed when an interrupt operation is performed during printing. [Solution] A recording device that records an image on a recording medium by alternating main scans that eject ink onto the recording medium and sub-scans that transport the recording medium a specified transport amount using a transport means, and when a specified interrupt operation is performed between a first main scan and the following second main scan, the recording medium is transported a specified transport amount using a small transport operation that includes a first small transport operation by the transport means and a subsequent second small transport operation, and the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing in a second direction between multiple air outlets so that the part of the recording medium facing the air outlet after the first small transport operation is not located in a position facing the air outlet after the second small transport operation is performed.

Description

[Technical Field]

[0001] The present invention relates to an inkjet printing apparatus and a printing method. [Background technology]

[0002] When an inkjet recording apparatus records on a recording medium with low ink absorbency, such as a polyvinyl chloride sheet, ink droplets remain in a liquid state on the recording medium for a long time, which can cause image defects such as ink bleeding on the recording medium. For this reason, some recording apparatuses are equipped with a drying device that uses air blowing or heating to promote evaporation of the solvent (liquid component) such as water or solvent in the ink droplets on the recording medium, thereby efficiently fixing the coloring material to the surface of the recording medium.

[0003] Inkjet printing devices perform printing by repeating a main scan, in which the print head ejects ink while moving relative to the print medium, and a sub-scan, in which the print medium is transported in a direction intersecting the main scan direction. In the print head of an inkjet printing device, mist adheres to the periphery of the nozzles, degrading the ink ejection characteristics. Therefore, if the printing time is long, maintenance operations such as wiping and suction must be performed midway through printing (the period between the first main scan and the following second main scan). If an interruption operation such as a maintenance operation is performed midway through printing, the transport of the print medium stops for a long time, and the print medium may remain in the drying device for a long time, potentially resulting in thermal damage to the print medium. Patent Document 1 describes a technology that shortens the residence time of the print medium in the drying device by transporting the print medium from the entrance to the exit of the drying device when an interruption operation such as a maintenance operation occurs.

[0004] One way to improve the drying efficiency of a drying device is to increase the heating temperature. However, increasing the heating temperature can cause problems such as thermal damage to the recording medium, such as expansion and contraction, and increased power consumption. Therefore, another way to improve drying efficiency is to use an impingement jet, which blows a jet of gas onto the recording medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-130900 A Summary of the Invention [Problem to be solved by the invention]

[0006] When a recording medium is dried using an impinging jet, image unevenness such as gloss difference may be visible. In particular, image unevenness is likely to occur when an interruption operation is performed during recording, causing the conveyance to stop for a long period of time.

[0007] The present invention aims to suppress the occurrence of image unevenness when an interrupt operation is performed during printing in a printing apparatus having a drying device that dries ink ejected onto a printing medium using a collision jet. [Means for solving the problem]

[0008] The present invention provides a recording head that ejects ink while moving relative to a recording medium in a first direction; a conveying means for conveying the recording medium in a second direction intersecting the first direction; a drying means having a plurality of blowout ports arranged in the second direction and configured to blow jets of gas from the blowout ports toward a surface of the recording medium onto which the ink has been ejected; The main scanning in which the recording head ejects ink onto the recording medium and the conveying means a control means for alternately performing a sub-scanning operation and a sub-scanning operation for conveying the recording medium by a fixed conveyance distance; A recording device comprising: when a predetermined interrupt operation is performed between a first main scan and a subsequent second main scan, the control means carries out a small-conveying operation including a first small-conveying operation and a subsequent second small-conveying operation by the conveying means to convey the recording medium by the specified conveying distance, This recording device is characterized in that the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing between the multiple air outlets in the second direction so that the part of the recording medium facing the air outlet after the first small transport operation is not positioned in a position facing the air outlet after the second small transport operation is performed. [Effects of the Invention]

[0009] According to the present invention, in a recording device having a drying device that dries ink ejected onto a recording medium using a collision jet, it is possible to suppress the occurrence of image unevenness when an interrupt operation is performed during recording. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing the internal configuration of a recording apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the configuration of a heating and drying mechanism of the recording apparatus according to the embodiment. [Figure 3] FIG. 2 is a diagram illustrating the configuration of a print head of a printing apparatus according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing a maintenance mechanism of the recording apparatus according to the embodiment. [Figure 5] 10 is a flowchart showing a wiping operation sequence according to an embodiment of the present invention. [Figure 6] FIG. 2 is a block diagram showing the functional configuration of the recording apparatus according to the embodiment. [Figure 7] FIG. 2 is a block diagram showing the functional configuration of a recording control unit of the recording apparatus according to the embodiment. [Figure 8] 3A to 3C are diagrams illustrating a recording method of the recording apparatus according to the embodiment. [Figure 9] 10A and 10B are diagrams for explaining image unevenness caused by drying using a collision jet. [Figure 10] 10A and 10B are diagrams for explaining image unevenness caused by drying using a collision jet. [Figure 11(a)] 10A and 10B are diagrams for explaining transport control during an interrupt operation in the first embodiment. [Figure 11(b)]10A and 10B are diagrams for explaining transport control during an interrupt operation in the first embodiment. [Figure 12] 10A and 10B are diagrams for explaining patterns of transport control that cannot suppress image unevenness. [Figure 13] 10 is a flowchart showing a transport control during an interrupt operation in the first embodiment. [Figure 14] 10A and 10B are diagrams for explaining transport control during an interrupt operation in the second embodiment. [Figure 15] 10A and 10B are diagrams for explaining transport control during an interrupt operation in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Example 1 Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the following examples may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and the scope of the present invention is not intended to be limited to the following examples.

[0012] 1 is a diagram showing the internal configuration of an inkjet recording apparatus 1 of Example 1. A drive belt 105 moves using a carriage motor 104 (hereinafter also referred to as a CR motor) as a drive source. As the drive belt 105 moves, a carriage 103 carrying recording heads 101 and 102 moves back and forth in the main scanning direction (first direction, X direction) while being guided and supported by a guide shaft 106. The recording heads 101 and 102 eject ink while moving relative to a recording medium 109 in the X direction.

[0013] The flexible cable 107 electrically connects the control board (not shown) provided in the main body of the recording apparatus 1 to the recording heads 101 and 102 while following the movement of the carriage 103. The pair of conveying rollers 108 is a conveying means that holds the recording medium 109 and conveys the recording medium 109 in a second direction (sub-scanning direction, Y direction) that intersects with the first direction (main scanning direction, X direction) as the conveying rollers rotate.

[0014] The recording device 1 alternately repeats main scanning and sub-scanning to gradually record an image corresponding to the recording data on the recording medium 109. The main scanning is an operation in which the carriage 103 moves in the main scanning direction while the recording heads 101 and 102 eject ink in accordance with the recording data. The sub-scan is an operation in which the recording medium 109 is conveyed a specified conveyance distance by the conveyance roller pair 108 between the first main scanning and the following second main scanning.

[0015] At one end of the X-direction movement range of the carriage 103, a maintenance mechanism 110 is provided that performs maintenance operations (recovery processes) to maintain the ejection function of the print heads 101 and 102 in good condition. The recovery processes include a suction operation, a wiping operation, and a preliminary ejection operation. The suction operation removes bubbles and impurities from inside the print heads 101 and 102 by forcibly sucking ink from the nozzles (ejection ports) of the print heads 101 and 102. The wiping operation wipes away droplets from the ink ejection surfaces of the print heads 101 and 102. The preliminary ejection operation involves preliminary ink ejection to regulate ejection prior to the actual printing of print data.

[0016] The recording medium 109 on which the ink is ejected and an image is formed is transported in the transport direction (Y direction), and a heating and drying mechanism 201 shown in Fig. 2 blows hot air onto the surface on which the ink is ejected, thereby heating and fixing the ink. The heating and drying mechanism 201 can also heat and form a film of resin particles, which will be described later. The resin particles are a substance that forms a film when heated after being applied to the recording medium 109, and improves the scratch resistance of the image.

[0017] 2 is a diagram showing the configuration of a heating and drying mechanism 201 according to an embodiment. The heating and drying mechanism 201 is provided downstream of the recording heads 101 and 102 in the Y direction. The heating and drying mechanism 201 has a plurality of jet holes 902, which are blowout ports, arranged in a second direction (Y direction). The heating and drying mechanism 201 is a drying means that dries the ink ejected onto the recording medium 109 by blowing a jet of gas from the jet holes 902 from above (+Z direction) the recording medium 109 toward the surface of the recording medium 109 onto which the ink has been ejected.

[0018] The heating and drying mechanism 201 includes a blower 202 with a blowing function, a heater 204 equipped with a heater 203 for heating the gas collected by the blower 202, and a jet unit 205 for blowing the heated gas onto the recording medium 109. The jet unit 205 is provided with a plurality of jet holes 902. Below the heater 204, there is a parallel flow unit 207, which is provided upstream of the jet unit 205 in the Y direction (second direction). The parallel flow unit 207 dries the ink ejected onto the recording medium 109 by flowing gas along the surface of the recording medium 109 onto which the ink has been ejected. The parallel flow unit 207 is not configured to blow warm air from above the recording medium 109, but rather the air ejected from the heater 204 flows in parallel along the surface of the recording medium 109. The parallel flow unit 207 also promotes evaporation of ink film components.

[0019] If the jet is applied immediately after ink is ejected onto the recording medium 109, image unevenness caused by the jet (jet unevenness) may occur. Therefore, by arranging the parallel flow section 207 upstream of the jet section 205 in the second direction (Y direction), the liquid component (water) of the ink is first evaporated to a certain extent in the parallel flow section 207, thereby suppressing jet unevenness.

[0020] Gas circulates within the heating and drying mechanism 201, which reduces power consumption. The airflow in the heating and drying mechanism 201 is indicated by dotted arrows in FIG. 2. Heated gas emitted from the jet section 205 passes through the parallel flow section 207 below the heating section 204, and is then collected from the collection section 206. This causes the gas to circulate within the heating and drying mechanism 201. Note that the recovery unit 206 does not have to be configured to recover and heat all of the heated gas. In order to suppress an increase in humidity within the heating and drying mechanism 201, it may be configured to take in a certain amount of outside air.

[0021] The higher the drying efficiency of the heating and drying mechanism 201, the shorter the heating and drying time required to fix the ink film, making it possible to reduce the size of the heating and drying mechanism 201. Furthermore, the higher the drying efficiency of the heating and drying mechanism 201, the less power is required for heating and drying by the heating and drying mechanism 201, making it possible to reduce power consumption.

[0022] The heating and drying mechanism 201 uses an impinging jet in the jet section 205, which causes a gas jet from the jet holes 902 to impinge on the recording medium 109. In other words, because heated gas is blown onto the object to be heated at a relatively high wind speed, drying efficiency can be improved without increasing the heating temperature as much as possible. When cooling or heating an object with the impinging jet, significant heat transfer is achieved near the stagnation point (spurt point) on the object surface where the jet impinges. In addition, the thermal load on the surface of the recording medium 109 can be adjusted by adjusting the diameter of the jet holes 902 and the distance between the jet holes 902 and the recording medium 109 where the jet impinges.

[0023] The heating and drying mechanism 201 using a collision jet can suppress thermal damage to the recording medium, such as expansion and contraction of the entire recording medium or partial expansion and contraction causing wavy patterns, as well as increased power consumption, compared to when the heating temperature is increased to improve drying efficiency.

[0024] The heating temperature of the heating and drying mechanism 201 is preferably equal to or higher than the minimum film-forming temperature of the resin particles contained in the ink in order to heat the resin particles. It is also preferable that the temperature be such that most of the liquid components in the ink, such as the water-soluble organic solvent, can evaporate during heating. The higher the heating temperature, the higher the drying efficiency. While there is no lower limit for the heating temperature, it is preferable that it be 60°C or higher, and more preferably 80°C or higher. On the other hand, if the heating temperature is too high, the recording medium may be deformed. Therefore, although there is no upper limit for the heating temperature, it is preferable that it be 120°C or lower, and more preferably 100°C or lower.

[0025] FIG. 3 is a diagram showing the configuration of the print heads 101 and 102 of the printing apparatus 1 of this embodiment. FIG. 3 is a view of the print heads 101 and 102 as seen from the printing medium 109 side, showing the ink ejection surface provided with a printing element array (nozzle array). The print heads 101 and 102 each have a nozzle array (ejection opening array) for each ink color, and eject ink for each ink color. The nozzle array consists of multiple nozzles arranged in the Y direction. In this embodiment, the nozzle array is configured with 2,400 nozzles arranged at a density of 1,200 nozzles per inch (1,200 dpi). The printing apparatus 1 of this embodiment has separate print heads 101 for color inks containing colorants and 102 for reaction liquids containing components that insolubilize or aggregate the colorants of the color inks. This makes it possible to suppress adverse reactions caused by floating mist.

[0026] Nozzle row 31C is a nozzle row in which nozzles that eject cyan ink are arranged. Nozzle row 31M is a nozzle row in which nozzles that eject magenta ink are arranged. Nozzle row 31Y is a nozzle row in which nozzles that eject yellow ink are arranged. Nozzle row 31BK is a nozzle row in which nozzles that eject black ink are arranged. Nozzle row 31LC is a nozzle row in which nozzles that eject light cyan ink are arranged. Nozzle row 31LM is a nozzle row in which nozzles that eject light magenta ink are arranged. These nozzle rows are arranged overlapping each other when viewed in the main scanning direction (X direction). Hereinafter, when there is no need to distinguish between the colors of nozzle rows 31C, 31M, 31Y, 31LC, 31LM, and 31BK, they may be simply referred to as nozzle row 31.

[0027] Nozzle rows 31C, 31M, 31Y, 31LC, 31LM, and 31BK of the recording head 101 Each of the recording heads 101 and 102 has two nozzle rows arranged side by side in the X direction, with nozzles arranged at a density of 600 per inch (600 dpi). The two nozzle rows (referred to as an even row and an odd row) are offset by 1 / 1200 inch in the sub-scanning direction so that the nozzles of both rows are arranged in a staggered pattern overall. By regarding these two rows as one nozzle row, it is possible to form 1200 dots per inch on the recording medium 109. In other words, the recording heads 101 and 102 can form an image at a recording density of 1200 dpi (dots / inch) in the sub-scanning direction. By ejecting ink droplets from each nozzle while moving the recording heads 101 and 102 in the main scanning direction, dots are recorded on the recording medium 109 at a density of 2400 dpi in the main scanning direction and 1200 dpi in the sub-scanning direction.

[0028] The volume of ink droplets ejected from each nozzle (ejection volume) is approximately 5 pL. However, the ejection volume of black ink may be set larger than that of other color inks to achieve high density. The print heads 101 and 102 of this embodiment eject ink using thermal energy. Each print element has an electrothermal converter for generating thermal energy.

[0029] The ink ejection method is not limited to the method using thermal energy, and other methods, such as a method of ejecting ink using a piezoelectric element, may also be used. Furthermore, the print head 101 ejecting the six colors of ink (C, M, Y, LC, LM, and BK) may be configured independently for each color, or may be configured as an integrated unit. In addition to the six colors of ink, red ink, green ink, blue ink, etc. may be used to improve color reproduction, and white ink may be added to improve color reproduction of the film.

[0030] The print head 102 for the reaction liquid has a nozzle array 32OPT for ejecting the reaction liquid, which is made up of 2400 nozzles (printing elements) arranged at a density of 1200 per inch, similar to the print head 101.

[0031] When ink is ejected by the print head, floating mist is generated. In this embodiment, the print head 101 for the color ink and the print head 102 for the reaction liquid are configured separately. Therefore, compared to when the print head for the color ink and the print head for the reaction liquid are integrated, the floating mist is prevented from reacting with each other and aggregating on the ejection surface of the print head. Note that the print head for the color ink and the print head for the reaction liquid may also be integrated. In this case, reaction caused by floating mist can be reduced by widening the interval between the nozzle array for the color ink and the nozzle array for the reaction liquid. Note that narrowing the interval between the nozzle arrays allows the size of the print head to be reduced.

[0032] (Maintenance Organization) 4 is a cross-sectional view showing the maintenance mechanism 110 of the recording apparatus 1 of the embodiment. The maintenance mechanism 110 has a wiping member 401 made of a sheet-like porous material that can wipe off ink adhering to the ink ejection surfaces of the recording head 101 and the recording head 102 (not shown).

[0033] An unused wiping member 401 (before wiping off ink) is wound around a first rotating member 402a. A second rotating member 402b is disposed downstream of the first rotating member 402a in the transport direction (Y direction) of the recording medium 109.

[0034] The tip of the wiping member 401 is attached to the second rotating member 402b, and the used wiping member 401 (after wiping off the ink) is taken up by the second rotating member 402b, which is driven by the wiping operation motor 614. This allows the wiping member 401 to be transported downstream in the transport direction of the recording medium 109 (Y direction).

[0035] On the other hand, the first rotating member 402a is rotated in accordance with the rotation of the second rotating member 402b. The transport amount (transport length) of the wiping member 401 is controlled by the rotation amount of the wiping operation motor 614. Note that the control of the transport amount of the wiping member 401 can also be performed based on the measurement results obtained by a measuring means that uses optical means.

[0036] A pressing member 403 is disposed between the first rotating member 402a and the second rotating member 402b. The pressing member 403 presses the wiping member 401 upward (in the Z direction) with a constant load using a compression spring 404. When the pressing member 403 presses the wiping member 401 up to a predetermined position, a part of the wiping member 401 comes into contact with the nozzle row 31 of the recording head 101.

[0037] The longer the length in the nozzle row direction (Y direction; wiping direction) of the wiping member 401 that is brought into contact with the nozzle row 31 by the pressing member 403, the greater the cleaning effect of the wiping operation. In this embodiment, the length in the Y direction of the wiping member 401 that is brought into contact with the nozzle row 31 by the pressing member 403 is approximately 5 mm. Furthermore, the width (length in the X direction) of the wiping member 401 that is brought into contact with the recording head 101 by the pressing member 403 is wide enough to wipe all of the nozzle row 31 of the recording head 101. In this embodiment, by making the width of the pressing member 403 longer than the width of the recording head 101, the width of the wiping member 401 that is brought into contact with the recording head 101 by the pressing member 403 is made approximately the same as the width of the recording head 101.

[0038] The wiping member 401 may be composed of one or more members. For example, the recording head 101 may have different wiping members 401 depending on the position of the nozzle rows 31 for each ink. Furthermore, if there are multiple recording heads, each recording head may be composed of multiple wiping members 401. The number of divisions of the wiping member 401 and the width, length, etc. of each division are not limited to the above example.

[0039] In this embodiment, the wiping member 401 uses a nonwoven fabric made of polyester staple fibers, but the raw material and manufacturing method are not particularly limited. The nonwoven fabric is formed in a sheet shape by bonding or entangling fibers by fusion or mechanical or chemical action. The wiping member 401 may also be a sheet-like member made of knitted or woven fabric made of long fibers. The wiping member 401 may also be made of a material such as a mixture of polyester and nylon, cotton, etc.

[0040] (wiping operation) In this embodiment, the wiping operation is performed at least during the recording operation. That is, the wiping operation is performed as a predetermined interrupt operation between the first main scan and the following second main scan. Other timings for performing the wiping operation include at the start of recording, between pages, before the cap closing operation, during the cleaning sequence (during the suction recovery sequence), etc.

[0041] The wiping operation at the start of recording is a wiping operation that is performed before the first page is recorded. Even if the ejection surface is contaminated with ink that has been adhering to the cap during standby, or if mist has adhered to the ejection surface due to preliminary ejection performed during standby, it can be wiped off by the wiping operation at the start of recording.

[0042] The wiping operation during printing is performed as a periodic maintenance operation, which prevents mist of the same or other color ink from the print heads 101 and 102 that is generated during printing from covering the nozzles, adhering to and solidifying on the ejection surface, or gathering together to form large droplets that fall.

[0043] The wiping operation between pages is a wiping operation that is performed after the previous page has been printed and before the next page has been printed, and also includes a wiping operation that is performed when the recording medium 109 is cut by the cutter process after all pages have been printed.

[0044] The wiping operation before the capping operation is performed for maintenance before capping the print heads 101 and 102 after printing is completed.

[0045] The wiping operation during the cleaning sequence is performed to wipe off a large amount of ink droplets adhering to the ejection surface after a recovery process such as ink suction using a cap has been performed.

[0046] 5 is a flowchart showing the wiping operation sequence of the embodiment. The process of this flowchart is executed by the CPU 608 of the recording control unit 607 in FIG.

[0047] In step S501, the CPU 608 moves the carriage 103 to above the maintenance mechanism 110, and moves the maintenance mechanism 110 to the wiping start position. In step S502, the CPU 608 winds up the wiping member 401, which has been soiled with ink in the previous wiping operation, by a predetermined length so that the unused portion is pressed against the ejection surfaces of the recording heads 101 and 102 by the pressing member 403. For example, the CPU 608 winds up approximately 5 mm, which is the length that contacts the nozzle row 31, as the winding operation.

[0048] In step S503, the CPU 608 raises the pressing member 403 and moves it to the wiping position. In step S504, the CPU 608 performs the wiping operation. That is, the CPU 608 moves the maintenance mechanism 110 from the wiping start position to the wiping end position. In step S505, the CPU 608 lowers the pressing member 403 and moves it to the standby position. In step S506, the CPU 608 returns the maintenance mechanism 110 to the wiping start position.

[0049] (Ink composition) Next, the ink formulations in the present examples will be described in detail. The present invention is not limited in any way by the following examples, provided that the gist of the invention is not exceeded. Note that "parts" and "%" in the text are by mass unless otherwise specified.

[0050] - Preparation of resin particle dispersion The ink of Example 1 contains resin microparticles that adhere to the recording medium and the colorant, improving the abrasion resistance (fixability) of the recorded image. The resin microparticles are melted by heat, and a heater is used to form a film of the resin microparticles and dry the solvent contained in the ink. In this example, "resin microparticles" refers to polymer microparticles that exist in a dispersed state in water. Specifically, these include acrylic resin microparticles synthesized by emulsion polymerization of monomers such as (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides. Styrene-acrylic resin microparticles synthesized by emulsion polymerization of styrene monomers such as (meth)acrylic acid alkyl esters or (meth)acrylic acid alkyl amides. Examples include polyethylene resin microparticles, polypropylene resin microparticles, polyurethane resin microparticles, and styrene-butadiene resin microparticles. Core-shell resin microparticles, in which the polymer composition of the core and shell of the resin microparticles differ, and resin microparticles obtained by emulsion polymerization around pre-synthesized acrylic microparticles used as seed particles to control particle size, may also be used. Furthermore, hybrid resin particles in which different resin particles such as acrylic resin particles and urethane resin particles are chemically bonded together may also be used.

[0051] Furthermore, "polymer particles dispersed in water" may be in the form of resin particles obtained by homopolymerizing or copolymerizing multiple types of monomers having a dissociative group, i.e., a so-called self-dispersing resin particle dispersion. Examples of the dissociative group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of monomers having this dissociative group include acrylic acid and methacrylic acid. Furthermore, so-called emulsions in which resin particles are dispersed using an emulsifier may also be used. As the emulsifier, a material having an anionic charge can be used regardless of whether it is a low molecular weight or a high molecular weight.

[0052] The resin particle dispersion used in this example was prepared by first adding the following three additives dropwise in small amounts while stirring in a nitrogen atmosphere heated to 70°C, and polymerizing for 5 hours. Each additive was a mixture containing a hydrophobic monomer consisting of 28.5 parts methyl methacrylate, a hydrophilic monomer consisting of 4.3 parts sodium p-styrenesulfonate and 30 parts water, and a polymerization initiator consisting of 0.05 parts potassium persulfate and 30 parts water. In this way, a 20% by mass resin particle dispersion was obtained.

[0053] The methods for preparing each ink and reaction liquid will be described below.

[0054] (Adjustment of black pigment dispersion) First, an anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (polymerization ratio (weight ratio) = 30 / 40 / 30), acid value 202, weight average molecular weight 6500] was prepared. This was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer aqueous solution.

[0055] 600 g of the polymer solution, 100 g of carbon black, and 300 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove undispersed material, including coarse particles, to obtain a black dispersion. The resulting black dispersion had a pigment concentration of 10% by mass.

[0056] (Preparation of Magenta Pigment Dispersion) First, an AB-type 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 by a conventional method. The polymer was then neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50% by mass aqueous polymer solution.

[0057] 100 g of the polymer solution, 100 g of CI Pigment Red 122, and 800 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove non-dispersed material including coarse particles, to obtain a magenta dispersion. The resulting magenta dispersion had a pigment concentration of 10% by mass.

[0058] (Preparation of Cyan Pigment Dispersion) First, an AB-type block polymer with an acid value of 250 and a number-average molecular weight of 3000 was prepared using benzyl acrylate and methacrylic acid as raw materials by a conventional method. The polymer was then neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 50% by mass aqueous polymer solution.

[0059] 200 g of the polymer solution, 100 g of CI Pigment Blue 15:3, and 700 g of ion-exchanged water were mixed and mechanically stirred for a predetermined time, followed by centrifugal separation to remove non-dispersed material, including coarse particles, to obtain a cyan dispersion. The resulting cyan dispersion had a pigment concentration of 10% by mass.

[0060] (Preparation of Yellow Pigment Dispersion) First, the anionic polymer P-1 was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass aqueous polymer solution.

[0061] 300 g of the polymer solution, 100 g of CI Pigment Yellow 74, and 600 g of ion-exchanged water were mixed, mechanically stirred for a predetermined time, and then centrifuged to remove non-dispersed matter including coarse particles, to obtain a yellow dispersion. The concentration was 10% by mass.

[0062] (Ink adjustment) Pigment inks 1 to 6 were prepared by mixing the components (unit: %) shown in the upper row of Table 1 and then filtering under pressure through a membrane filter (HDCII filter; manufactured by Pall) with a pore size of 1.2 μm. The amount of ion-exchanged water used was determined so that the total amount of the components would be 100.0%. Acetylenol E100 is a surfactant manufactured by Kawaken Fine Chemicals. The lower row of Table 1 shows the pigment content (unit: %) in the pigment ink. Each of the inks obtained in this manner was filled into a cartridge. [Table 1]

[0063] (Preparation of reaction solution) The reaction liquid used in this example contains a reactive component that reacts with the pigment contained in the ink and causes the pigment to aggregate or gel. Specifically, this reactive component is a component that, when mixed on a recording medium or the like with an ink containing a pigment stably dispersed in an aqueous medium by the action of ionic groups, can destroy the dispersion stability of the ink. Specifically, magnesium sulfate is used in this example.

[0064] It is not necessary to use magnesium sulfate, and in this example, various water-soluble organic acids and polyvalent metal salts can be used as reactive components in the reaction solution. The content of the organic acid or polyvalent metal salt is preferably 0.1% by mass or more and 90.0% by mass or less, and more preferably 1.0% by mass or more and 70.0% by mass or less, based on the total mass of the composition contained in the reaction solution.

[0065] Ink preparation In this example, as described above, magnesium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used, and the following components were mixed to prepare reaction solution 1. Magnesium sulfate 2 parts 2-pyrrolidone 5 parts 2-methyl-1,3-propanediol 15 parts Acetylene glycol EO adduct 0.5 parts Ion-exchanged water (manufactured by Kawaken Fine Chemicals Co., Ltd.) Remaining

[0066] (Image processing system configuration example) 6 is a block diagram showing the functional configuration (control configuration) of the recording apparatus 1 of this embodiment. First, image data (multi-valued data) stored in an image input device 601 such as a scanner or digital camera or in various storage media such as a hard disk is input to an image input unit 602. The image input unit 602 is a host computer connected to the outside of the recording apparatus 1, and transfers image information (image data) to be recorded to an image output unit 604, which is the recording apparatus 1, via an interface circuit 603. The image input unit 602 is provided with a CPU 605 and a memory element (ROM 606) required for transferring image data. The host computer may take the form of an information processing computer or may take the form of an image reader, etc.

[0067] The print control unit 607 has a CPU 608, an input / output port 609, a storage element (ROM 610) that stores control programs and the like, and a RAM 611 that serves as a work area when various image processing operations are performed. The ROM 610 stores various data such as the control program for the CPU 608 and parameters necessary for print operations. The RAM 611 is used as a work area for the CPU 608 and also temporarily stores various data such as image data received from the image input unit 602 and generated print data. Then, based on the image data converted by the print control unit 607, an image is formed by applying ink from the nozzles of the print heads 101 and 102 to the print medium 109.

[0068] The recording control unit 607 is connected via an input / output port 609 to the carriage motor 104 and transport motor 612 (also referred to as an LF motor) in the transport unit, and drive circuits 615, 616, and 619 for the recording heads 101 and 102. The recording control unit 607 is also connected via the input / output port 609 to drive circuits 617 and 618 for a recovery operation motor 613 and a wiping operation motor 614. The recovery operation motor 613 is a drive source for suctioning ink from each nozzle during the recovery operation of a recovery processing unit (not shown) that recovers ejection from non-ejecting nozzles in the recording heads 101 and 102. The recording control unit 607 is also connected via the input / output port 609 to a drive circuit 620 for driving the heating element 203 of the heating and drying mechanism 201 and a drive circuit 621 for driving the air blower 202.

[0069] Furthermore, sensors such as a temperature and humidity sensor 623 that detects the temperature and humidity of the surrounding environment are connected to the input / output port 609. A signal from an encoder sensor 622 that detects the position of the carriage 103 is also input to the recording control unit 607 via the input / output port 609. The recording control unit 607 is a control means that controls alternating main scanning, in which the recording heads 101 and 102 eject ink onto the recording medium 109, and sub-scanning, in which the conveying means (pair of conveying rollers 108) convey the recording medium 109 a specified conveyance distance.

[0070] (Block diagram) Fig. 7 is a block diagram showing the functional configuration of the recording control unit 607 shown in Fig. 6. The recording control unit 607 determines which nozzle to use to record on the recording medium 109 for each pixel of image data.

[0071] Input image data input from the image input unit 602, which is composed of 8 bits for each of the colors R, G, and B, is input to a color conversion processing unit 701 and converted into density signals for C, M, Y, and K. The color conversion processing unit 701 converts the input image data (RGB data) into multi-tone data (CMYK data) of multiple ink colors that can be used by the recording device 1 for each pixel, while referring to a 3D-LUT 702, which is a three-dimensional color conversion lookup table.

[0072] The number of dimensions of the color conversion lookup table of the 3D-LUT 702 is set to the color conversion processing unit 701. The number of components of the input image data is referred to as the number of components. The 3D-LUT 702 holds density signals for specific and discrete RGB signals. Of all the combinations of RGB values ​​expressed in 256 levels for each color, for RGB signals for which values ​​are not held in the 3D-LUT 702, the color conversion processing unit 701 uses the multiple data held to determine CMYK signals through interpolation processing. The interpolation processing method is a well-known technique, so a detailed description will be omitted. The values ​​of the multi-tone data (CMYK data) acquired by the color conversion processing unit 701 are expressed in 8 bits, just like the input image data that is the input value, and are output as density data having 256 levels of gradation values.

[0073] The CMYK data that has been color converted in the color conversion processing unit 701 is then converted by an output gamma correction unit 703. The output gamma correction unit 703 performs correction for each ink color by referencing a 1D-LUT 704, which is a one-dimensional color conversion lookup table, so that the optical density finally expressed on the recording medium 109 maintains linearity with respect to the input density signal. The C'M'Y'K' data that is the output signal from the output gamma correction unit 703 is 8-bit density data, just like the input image data.

[0074] This 8-bit density data is converted by a binarization processor 705 into 1-bit binary image data that defines the positions of dots to be printed by the print heads 101 and 102. The binarization processor 705 can employ a general multi-level error diffusion process.

[0075] Based on this binary image data, a mask pattern processing unit 706 selects a mask pattern to be used and creates output image data for each main scan.

[0076] The optimal conversion methods in the color conversion processing unit 701, output gamma correction unit 703, and binarization processing unit 705 described above differ depending on the type of recording medium 109, the type of image to be recorded, etc. In particular, the three-dimensional color conversion lookup table of the 3D-LUT 702 used in the color conversion processing unit 701 is prepared for each type of recording medium 109.

[0077] 8 is a diagram showing the printing method of the printing apparatus 1 of this embodiment. The mask pattern used by the mask pattern processing unit 706 is stored in the ROM 610 of the printing control unit 607. The mask pattern processing unit 706 uses the mask pattern to divide the printing data of each color for each printing scan, and generates dot data to be printed for each printing scan of each color.

[0078] FIG. 8(A) shows the print duty of a unit pixel 801, and in this example, the print duty of the unit pixel 801 is 50%. The unit pixel 801 undergoes binarization processing and resolution conversion in the binarization processing unit 705, and binary image data 802 shown in FIG. 8(B) is generated. In this example, the binary image data 802 consists of 4 dots x 2 dots. The blacked-out areas in FIG. 8(B) indicate dots that will be printed. In this example, 4 dots out of 8 dots will be printed, which results in a print duty of 50%.

[0079] Mask pattern 803 in Figure 8(C) is an example of a mask pattern used in four-pass multi-pass printing, which prints an image using four printing scans. The mask pattern determines the printed and non-printed areas for each dot. In Figure 8(C), black areas indicate dots that are allowed to be printed, and white areas indicate dots that are not allowed to be printed. The print permission rates of the four mask patterns 803a, 803b, 803c, and 803d are each 25%, and they complement each other.

[0080] The nozzles in the nozzle row 31 are divided into four regions in the vertical direction (Y direction), and each region corresponds to a mask pattern 803a to 803d. The nozzles included in each region print dots according to the mask patterns 803a to 803d corresponding to each region. By taking the logical product of the dots 803a to 803d and the binary image data 802 generated by the binarization processing unit 705, the dots to be actually printed in each printing scan are determined.

[0081] Output image data 804 in Figure 8(D) shows the positions of dots printed in each printing scan. In the example of Figure 8(D), it can be seen that one dot is printed per printing scan. For example, output image data 804b printed in the second printing scan is obtained from the logical product of binary image data 802 and mask pattern 803b. A dot is actually printed only if there is a dot to be printed in binary image data 802 and printing is permitted in mask pattern 803.

[0082] When dots are actually printed on the print medium 109, the print medium 109 is conveyed a fixed conveyance amount (prescribed conveyance amount) each time a print scan is performed, thereby realizing overlapping prints from multiple print scans. In the example of Fig. 8, the data shown in the binary image data 802 is printed by conveying the print medium 109 by two dots per print scan. This conveyance amount is also called the print scan width.

[0083] 8 shows a mask pattern having a 4 dot x 2 dot area for ease of explanation, but an actual mask pattern may have a larger area in both the main scanning direction and the sub-scanning direction. In particular, in the sub-scanning direction, it is common for the number of nozzles in the nozzle array of the print head to be the same as the number of pixels in the mask pattern.

[0084] As explained above, the dots that are permitted to be printed are determined for each printing operation, and by performing multiple printing operations, ink of the target printing duty is printed on the printing medium 109. The ink applied to the printing medium 109 exhibits robustness by evaporating most of the liquid components, such as water-soluble organic solvents, in the heating and drying mechanism 201, causing the resin particles contained in the ink to form a film. In this embodiment, the heating and drying mechanism 201 is configured to use an impinging jet. Drying devices that use an impinging jet can cause image unevenness (also known as jet unevenness) due to differences in evaporation speed.

[0085] (Mechanism of uneven jet flow) The details of the jet unevenness will be explained below using Figure 9. Figure 9(a) is a view of the jet unit 205 of the heating and drying mechanism 201 as viewed in the Z direction. The portion of the jet unit 205 facing the recording medium 109 has jet holes 902 opened at a uniform pitch on a metal plate 901. In this embodiment, the diameter of the jet holes 902 is 1 mm. An efficient pitch layout varies depending on the size of the jet holes 902, but in this embodiment, the distance between the centers of the jet holes 902 (the spacing in the X direction) is 3.5 mm. Note that the size and pitch of the jet holes 902 are just examples; the effect of this embodiment can be achieved even if the jet holes 902 have a diameter of 0.5 mm or 2 mm. The pitch of the jet holes 902 can be changed depending on the size of the jet holes 902.

[0086] In principle, in the heating and drying mechanism 201 using a jet, a difference in evaporation rate can occur between the area directly below the jet hole 902 and the area around it, depending on the difference in heat transfer coefficient.

[0087] FIG. 9B shows how an ink film 903 ejected onto the recording medium 109 during a recording operation by the recording heads 101 and 102 enters directly below the jet portion 205 in the heating and drying mechanism 201 as the recording medium is transported by sub-scanning. The recording apparatus 1 of this embodiment performs recording using a serial scan method in which main scanning and sub-scanning are alternately repeated. In FIG. 9B, the recording medium 109 is transported 907 in the Y direction between stop periods S904 and S905, and is transported 908 in the Y direction between stop periods S905 and S906. During each stop period, the recording heads 101 and 102 perform a recording operation for one recording scan. The recording medium 109 is not transported while the recording heads 101 and 102 are performing a recording operation.

[0088] The ink film 903 ejected onto the recording medium 109 advances through the heating and drying mechanism 201 as transports 907 and 908 progress during stop periods S904, S905, and S906. The distance the recording medium 109 on which the ink film 903 is formed moves per transport is determined by the transport distance of the recording medium 109 performed directly below the print heads 101 and 102. In other words, the transport distance during transports 907 and 908 within the heating and drying mechanism 201 is the same as the print scan width. Considering only the fixation of the ink film 903, it is sufficient to ensure the time required for the ink film 903 to pass through the heating and drying mechanism 201, so the transport distance does not need to be the same as the print scan width. However, in this embodiment, the multi-pass printing is performed on the recording medium 109 while the ejected ink film 903 is fixed and dried at the same time. In order to transport the recording medium 109 so as to prevent misalignment of the dots during the print scans described above, the transport distance and the print scan width are the same unless reverse transport is performed.

[0089] When an impinging jet of liquid impinges on an ink film 903 on a recording medium 109, uneven film formation occurs due to differences in evaporation speed, which can result in image unevenness (jet unevenness) that is visually recognized as gloss differences (gloss unevenness). Generally, when there is a difference in evaporation speed during the drying process of a liquid film, a phenomenon (convection) occurs in which liquid components are attracted to areas with a faster evaporation rate as they evaporate. As shown in Figure 9(c), the difference in evaporation speed causes unevenness in the distribution of ink components within the ink film 903, which is thought to lead to image unevenness after fixing. Jet unevenness becomes more pronounced as the amount of reaction liquid applied increases. This is thought to be because the physical properties of the reaction liquid and the color ink differ, which makes the difference in evaporation speed more pronounced and causes unevenness in the ink components within the surface.

[0090] The effect of the difference in evaporation rate due to the impinging jet becomes more pronounced the longer the ink film 903 remains stationary under the jet. In a serial scan printing method, the recording medium 109 remains stationary under the jet while the print heads 101 and 102 print for one print scan. By evaporating some of the water before entering the area under the impinging jet, jet unevenness due to the difference in evaporation rate can be suppressed. To evaporate water upstream of the impinging jet, in this embodiment, as described with reference to FIG. 2, a parallel flow section 207 is provided upstream of the jet section 205 that impinges the impinging jet to promote water evaporation. This evaporates the water in the ink film 903, increasing the viscosity of the entire ink film 903. This suppresses convection in the ink film 903 and suppresses the effect of the difference in evaporation rate in the jet section 205. A separate drying device may be provided upstream of the impinging jet.

[0091] If a recording stop (transport stop) occurs due to an interrupt operation such as a wiping operation between the first main scan and the subsequent second main scan, the period during which the recording medium 109 is stopped at the jet flow unit 205 becomes longer. In this case, even if the moisture in the ink film 903 has evaporated to some extent in the parallel flow unit 207 upstream of the jet flow unit 205, jet flow unevenness may occur. It is possible to suppress jet flow unevenness when a recording stop occurs by increasing the size of the parallel flow unit 207 in the transport direction, but this leads to an increase in the size of the heating and drying mechanism 201.

[0092] FIG. 10 is a diagram showing a schematic diagram of jet unevenness occurring when a wiping operation is performed during a printing operation. As shown in state S1002, the ink film 1001 ejected onto the printing medium 109 enters the heating and drying mechanism 201 as it is transported after ejection. At this time, the ink film 1001 is located in the parallel flow section 207, and the parallel flow of hot air primarily promotes evaporation of water. A printing scan is performed by the print heads 101 and 102, and a transport operation is performed across the printing scan width indicated by arrow 1007. As shown in state S1003, a region 1006 of the ink film 1001 is positioned directly below the jet holes 902. Note that each transport operation is controlled, for example, by trapezoidal drive with constant acceleration during acceleration, constant speed, and deceleration, or by S-shaped drive with smooth speed changes during trapezoidal drive.

[0093] If a wiping operation is inserted as an interrupt operation after the transport operation indicated by arrow 1007 is completed, the jet will continue to hit area 1006 for a longer period of time than a normal print scan, resulting in jet unevenness 1008 as shown in state S1004. By subsequently performing a print scan and a transport operation of the print scan width indicated by arrow 1009, area 1006 moves from the opposing position directly below jet hole 902 as shown in state S1005, but the jet unevenness 1008 that has occurred will not disappear.

[0094] 10 is a schematic representation of the jet unevenness 1008, and in reality the jet unevenness 1008 occurs in a certain range of area including directly below the jet portion 205. The size of the area where the jet unevenness 1008 occurs varies depending on the speed of the jet and the size of the jet hole 902. Furthermore, the jet unevenness 1008 can only actually be seen after the heating and drying is complete and the ink has fixed on the recording medium 109; at the stage of state S1004, liquid components remain, so the jet unevenness 1008 cannot be seen.

[0095] According to this embodiment, even when an interrupt operation is performed during recording, it is possible to prevent jet flow irregularities from occurring. This will be explained in detail below.

[0096] The recording device 1 of this embodiment performs recording by alternately repeating main scans and sub-scans that transport the recording medium a specified transport amount. When a predetermined interrupt operation, such as a wiping operation, is performed between a first main scan and the subsequent second main scan, the recording medium is transported the specified transport amount through a small transport operation that includes a first small transport operation and a subsequent second small transport operation by the transport means. In other words, instead of performing a sub-scan through a single transport operation of the specified transport amount, the sub-scan is performed through multiple small transport operations. The transport amount through the small transport operations is determined so that the portion of the recording medium 109 that stops facing the jet holes 902 after the first small transport operation is not located at the same position where the recording medium 109 stops facing the jet holes 902 after the second small transport operation. The transport amount through the small transport operation is determined based on the spacing between the jet holes 902 in the second direction (Y direction). The transport amount through the small transport operation is less than the specified transport amount. The first small transport operation and the second small transport operation may be performed with an interval between them. Each small transfer operation is controlled by trapezoidal drive, which consists of constant acceleration, constant speed, and deceleration, or by S-curve drive, which is a trapezoidal drive with smooth speed changes.

[0097] 11(a) and 11(b) are diagrams illustrating transport control during an interruption operation in this embodiment. As shown in state S1102, the ink film 1101 ejected onto the recording medium 109 enters the interior of the heating and drying mechanism 201 as it is transported after being ejected, but is located at the parallel flow section 207 and does not reach the jet section 205. At the timing of state S1102 when the ink film 1101 has been recorded, a wiping operation by the maintenance mechanism 110 is performed as an interruption operation.

[0098] In the normal transport control described above with reference to FIG. 10, the recording medium 109 is transported to the position of state S1104 in order to advance the recording medium 109 in preparation for the next recording. In the transport control of this embodiment shown in FIGS. 11(a) and 11(b), two small transport operations are performed while the wiping operation is being performed, so that the recording medium 109 moves to the positions shown in states S1103 and S1104. The small transport operation is a transport operation with a transport amount less than the specified transport amount (printing scan width). The total transport amount of the two small transport operations is equal to the specified transport amount. The two small transport operations may be performed with an interval between them. Of the two small transport operations, the state in which the recording medium 109 stops after the first small transport operation 1108 is performed is state S1103, and the state in which the recording medium 109 stops after the second small transport operation 1109 is performed is state S1104. Subsequently, a print scan and a conveying operation by the print scan width indicated by an arrow 1110 are performed, and the print medium 109 moves to the position indicated by state S1105.

[0099] The transport amount of the first small transport operation 1108 and the transport amount of the next second small transport operation 1109 are The spacing is determined as follows based on the spacing of the holes 902 in the second direction (transport direction, Y direction). That is, the spacing is determined so that the portion of the recording medium 109 that stops facing the jet hole 902 after performing the first small transport operation 1108 is not located at a position where the recording medium 109 stops facing the jet hole 902 after performing the second small transport operation 1109. As a result, the region 1106 directly below the jet hole 902 in state S1103 and the region 1107 directly below the jet hole 902 in state S1104 are located at different positions on the recording medium 109.

[0100] As a result, the area 1106 where the jet collides in state S1103 and the area 1107 where the jet collides in state S1104 do not overlap. In this way, the transport operation of the specified transport amount between the first main scan and the subsequent second main scan is divided taking into account the pitch of the jet holes 902 so as to shift the positions of the ink film 1101 and the jet holes 902. This shortens the time that the same area of ​​the ink film 1101 stops directly under the jet portion 205. This makes it possible to suppress the occurrence of jet unevenness. In this embodiment, a wiping operation and two short transport operations shorter than the printing scan width (specified transport amount) are performed between the first main scan and the second main scan. If the transport operation characteristic of this embodiment is not performed, a wiping operation and a transport operation (sub-scan) of one printing scan width (specified transport amount) are performed between the first main scan and the second main scan. In this embodiment, when an interrupt operation is performed, the number of transport operations performed between the first main scan and the second main scan is simply increased by one.

[0101] The transport amount of the small transport operation in this embodiment will be explained using FIG. 11B. The print heads 101 and 102 in this embodiment have 2400 nozzles at a density of 1200 dpi in the sub-scanning direction (Y direction), and the size of the nozzle array in the sub-scanning direction is approximately 50.8 mm. Because a four-division print scan is performed, the print scan width is approximately 12.7 mm, and the transport amount of the transport operation indicated by arrow 1110 is the same as print scan widths 1113 and 1114. As described in FIG. 9A, the pitch 1111 of the jet holes 902 in the X direction is 3.5 mm, so the interval 1112 between the jet holes 902 in the transport direction (Y direction) is approximately 6.1 mm. Transport control is performed so that the sum of the transport amount of the first small transport operation 1108 and the transport amount of the second small transport operation 1109 is approximately 12.7 mm, which is the specified transport amount (print scan width). Furthermore, the transport distance of each small transport operation is determined so that the portion facing the jet hole 902 after the first small transport operation 1108 is not positioned facing the jet hole 902 after the second small transport operation 1109. For example, the transport distance of the first small transport operation 1108 is set to 7.8 mm, and the transport distance of the second small transport operation 1109 is set to 4.9 mm. Note that the time required for the wiping operation is approximately 5 seconds, but this embodiment can also be applied to a time longer than 5 seconds, such as 10 seconds, or shorter, such as 3 seconds.

[0102] FIG. 12 is a diagram illustrating a comparative example in which a small-transport operation smaller than the print scan width is performed without considering the pitch of the jet holes 902 before and after the wiping operation. As shown in state S1202, the ink film 1201 ejected onto the print medium 109 enters the interior of the heating and drying mechanism 201 due to the transport after the ink film 1201 is ejected. The wiping operation is performed at this timing. In the comparative example of FIG. 12, two small-transport operations 1208 and 1209 are performed while the wiping operation is being performed. The sum of the transport distances achieved by the two small-transport operations 1208 and 1209 is equal to the specified transport distance. Of the two small-transport operations, the state in which the print medium 109 stops after the first small-transport operation 1208 is performed is state S1203, and the state in which the print medium 109 stops after the second small-transport operation 1209 is performed is state S1204. The two small-transport operations 1208 and 1209 may be performed with an interval between them. Subsequently, a print scan and a conveying operation by the print scan width indicated by an arrow 1210 are performed, and the print medium 109 moves to the position indicated by state S1205.

[0103] 12, an area 1206 of the recording medium 109 facing the jet hole 902 after the first small-conveying operation 1208 has been performed overlaps with an area 1207 of the recording medium 109 facing the jet hole 902 after the second small-conveying operation 1209 has been performed. Therefore, even though two small-conveying operations have been performed, jet unevenness occurs in the area 1207.

[0104] 13 is a flowchart showing the transport control during an interrupt operation in this embodiment. The process shown in this flowchart is executed by the CPU 608 of the recording control unit 607 in FIG.

[0105] When print data is sent to the printing apparatus 1, in step S1302, the CPU 608 performs print scanning (main scanning) with the print heads 101 and 102. When the main scanning is completed, in step S1303, the CPU 608 determines whether to perform a wiping operation.

[0106] If the wiping operation is not to be performed (step S1303: NO), the CPU 608 performs a conveying process (sub-scanning) of the recording medium 109 by the conveying motor 612 by a specified conveying amount (recording scanning width) in step S1301.

[0107] When the wiping operation is to be performed (step S1303: YES), the CPU 608 performs a first small transport operation in step S1304 and a second small transport operation in step S1305, thereby transporting the recording medium 109 a total of the specified transport distance. In addition, the CPU 608 performs a wiping operation in step S1306 in parallel with the two small transport operations. The wiping operation in step S1306 is the process described with reference to FIG. 5.

[0108] The two small conveying operations in steps S1304 and S1305 and the wiping operation in step S1306 may be performed in parallel, or the wiping operation (S1306) may be performed between the first small conveying operation (S1304) and the second small conveying operation (S1305). When the first small conveying operation, wiping operation, and second small conveying operation are performed sequentially, even if the conveying motor 612 and the wiping operation motor 614 are the same motor, the conveying control of this embodiment can be performed by switching gears.

[0109] After the sub-scanning in step S1301 is completed, or after the small conveying operation and wiping operation in steps S1304, S1305, and S1306 are completed, the CPU 608 determines in S1307 whether the recording of image data is completed. If completed (step S1307: YES), the CPU 608 ends the recording sequence, and if not completed (step S1307: NO), the CPU 608 returns to step S1302.

[0110] As described above, according to this embodiment, in a recording apparatus having a drying device that dries ink ejected onto a recording medium using a collision jet, it is possible to suppress the occurrence of image unevenness when an interruption operation is performed during recording. When the recording operation is stopped due to an interruption operation such as a wiping operation, the occurrence of jet unevenness can be suppressed by performing multiple small conveyance operations of the recording medium before and after the interruption operation, using a conveyance amount that is narrower than the recording scan width and determined taking into account the pitch of the jet holes.

[0111] Example 2 In the first embodiment, two small conveying operations are performed during the wiping operation, and the pitch of the jet holes 902 is a uniform pattern of 3.5 mm as shown in FIG. 11(b). In the second embodiment, the pitch of the jet holes in the jet unit 205 of the heating and drying mechanism 201 is changed between the upstream side (first half) and the downstream side (second half) in the Y direction (conveyance direction). FIG. 14(A) is a diagram showing the configuration of the jet unit 205 of the heating and drying mechanism 201 in the second embodiment. In the portion of the jet unit 205 facing the recording medium 109, jet holes 1402 are opened in a metal plate 1401. In the upstream portion in the Y direction, the pitch 1403 of the jet holes 1402 is 3.5 mm, as in the first embodiment. In the downstream portion in the Y direction, the pitch 1404 of the jet holes 1402 is 7.0 mm.

[0112] 14B is a diagram for explaining the transport control of the second embodiment. When a wiping operation is performed as an interrupt operation between a first main scan and the following second main scan, a first small transport operation 1405 and a second small The transport operation 1406 is performed to transport the sheet by a specified transport amount (printing scan width). The transport amounts of the first small transport operation 1405 and the second small transport operation 1406 are the same as the transport amounts of the first small transport operation 1108 and the second small transport operation 1109 shown in FIGS. 11(a) and 11(b) of the first embodiment. The first small transport operation 1405 and the second small transport operation 1406 may be performed with an interval between them.

[0113] When drying using a collision jet, the greater the moisture content of the ink film, the greater the effect of differences in evaporation speed, so the transport amount for the small transport operation is determined based on the pitch (3.5 mm) of the jet holes 1402 in the upstream portion. Note that it is easier to determine the transport amount for the small transport operation 1405 if the jet holes 1402 are arranged at a uniform pitch in the region of the jet section 205 where the jet is first sprayed onto the recording medium 109 (the upstream region). However, even if the jet holes 1402 are not arranged at a uniform pitch, it is possible to prevent the jet from repeatedly hitting the same location by appropriately adjusting the transport amount for the small transport operation based on the pitch of the jet holes 1402.

[0114] (Other Examples) In Examples 1 and 2, two small transport operations are performed during the wiping operation, but the transport may be divided into any number of operations as long as the total transport amount of the small transport operations is the same as the specified transport amount (printing scan width) and falls within the time of the wiping operation.

[0115] 15 shows an example of transport control in which four small transport operations are performed when an interrupt operation such as a wiping operation is performed. As shown in state 1504, an ink film 1503 ejected onto the recording medium 109 enters the interior of the heating and drying mechanism 201 as it is transported after being ejected, but is located at the parallel flow section 207 and does not reach the jet section 205. At the timing of state S1504 in which the ink film 1503 has been recorded, a wiping operation by the maintenance mechanism 110 is performed as an interrupt operation.

[0116] In the example of Figure 15, four small transport operations 1506, 1508, 1510, and 1512 are performed while the wiping operation is being performed. As a result, the recording medium 109 moves to the positions shown in states S1507, S1509, S1511, and S1513, respectively, and then stops. The total transport amount by the four small transport operations is equal to the specified transport amount (printing scan width). Next, a printing scan and a transport operation of the printing scan width shown by arrow 1514 are performed, and the recording medium 109 moves to the position shown in state S1515.

[0117] The transport amount of each small transport operation is determined as follows: After the first small transport operation 1506, position A of the recording medium 109 that stops facing the jet holes 1502 opened in the metal plate 1501 is not located at position B of the recording medium 109 that stops facing the jet holes 1502 after the second small transport operation 1508. After the second small transport operation 1508, positions A and B that have stopped facing the jet holes 1502 until now are not located at position C of the recording medium 109 that stops facing the jet holes 1502 after the third small transport operation 1510. After the third small transport operation 1510, positions A, B, and C of the recording medium 109 that have stopped facing the jet holes 1502 until now are not located at position D of the recording medium 109 that stops facing the jet holes 1502 after the fourth small transport operation 1512.

[0118] In this way, by determining the transport amount and performing a small transport operation, and performing the small transport operation multiple times so that the points where the nozzles stop directly below the jet holes 1502 do not overlap, it is possible to suppress the occurrence of jet unevenness.

[0119] Increasing the number of small transport operations reduces the possibility of jet unevenness occurring, but if the number of operations is too large, it becomes difficult to determine the transport amount of the small transport operation taking into account the pitch of the jet holes. In this embodiment, the transport amount is determined so that areas slightly wider than the diameter of the jet holes do not overlap directly below the jet holes. By determining the transport amount so that areas of the same diameter as the jet holes do not overlap, it is possible to suppress jet unevenness.

[0120] In addition, interrupt operations (recovery operations) performed during printing operations include suction operations in addition to wiping operations performed by the maintenance mechanism. However, suction operations require a longer downtime than wiping operations. For example, a wiping operation takes 5 seconds, while a suction operation takes 60 seconds. Assuming the pitch of the jet holes is the same as in Example 1 described in Figure 11(b), 24 small transport operations are required to maintain the same time directly below the jet holes as when two small transport operations are performed in Example 1. To perform 24 small transport operations within a printing scan width of 12.7 mm, the average transport distance is 0.5 mm. Considering that the diameter of the jet holes is 1 mm, it is difficult to determine the transport distance while taking the jet hole pitch into account. Therefore, in the case of long-duration interrupt operations such as suction operations, even if the interrupt operation is divided into multiple small transport operations and sub-scans are performed as in the above example, jet unevenness may still occur.

[0121] Furthermore, after recording on the recording medium is completed, the ink film is dried and fixed, and in this case, performing small transport operations before and after the wiping operation has the effect of suppressing jet unevenness.Since there is no need to consider dot overlap for each recording scan, there is no need to match the total amount of small transport operations with the recording scan width, but when considering the continuity of control, it is desirable to perform the same control as before recording was completed.

[0122] In addition, in the embodiment, an example is shown in which a print head having two nozzle rows, an even row and an odd row, for one color of ink is used, but a print head having more than one nozzle row for one color may also be used.

[0123] Furthermore, the present invention is applicable to all recording devices that use recording media such as paper, cloth, nonwoven fabric, and transparency film, and is not limited to the type of recording media. Since the present invention can simultaneously achieve short ink drying times using an impinging jet and suppression of jet unevenness during interruption operations, it is particularly suitable for use with recording media that do not absorb the liquid components of the ink or have low absorbency. Specific examples of applicable devices include office machines such as printers, copiers, and facsimiles, mass production machines, and industrial applications such as semiconductor devices.

[0124] In the above-described embodiment, the recording control unit 607, which performs the characteristic processing of the present invention, is provided inside the inkjet recording apparatus. However, the recording control unit 607 does not have to be provided inside the inkjet recording apparatus. For example, the functions of the recording control unit 607 may be provided in a printer driver of a host computer (image input unit 602) connected to the inkjet recording apparatus. In this way, an inkjet recording system comprising a host computer and an inkjet recording apparatus also falls within the scope of the present invention. In this case, the host computer functions as a data supply device that supplies data to the inkjet recording apparatus, and also functions as a control device that controls the inkjet recording apparatus.

[0125] The disclosure of this embodiment includes the following configuration. (Configuration 1) a recording head that ejects ink while moving relative to a recording medium in a first direction; a conveying means for conveying the recording medium in a second direction intersecting the first direction; a drying means having a plurality of blowout ports arranged in the second direction and configured to blow jets of gas from the blowout ports toward a surface of the recording medium onto which the ink has been ejected; a control means for alternately performing a main scan in which the recording head ejects ink onto the recording medium and a sub scan in which the conveying means conveys the recording medium a specified conveyance distance; A recording device comprising: when a predetermined interrupt operation is performed between a first main scan and a subsequent second main scan, the control means carries out a small-conveying operation including a first small-conveying operation and a subsequent second small-conveying operation by the conveying means to convey the recording medium by the specified conveying distance, A recording device characterized in that the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing between the multiple air outlets in the second direction so that the part of the recording medium facing the air outlet after the first small transport operation is not positioned in a position facing the air outlet after the second small transport operation is performed. (Configuration 2) 2. The recording apparatus according to configuration 1, wherein the control means performs the first small transport operation and the second small transport operation with an interval therebetween. (Configuration 3) A recording device described in configuration 1 or 2, wherein the transport amounts of the first small transport operation and the second small transport operation are determined so that the location of the recording medium that stops facing the air outlet after performing the first small transport operation is not located at a position where the recording medium stops facing the air outlet after performing the second small transport operation. (Configuration 4) The recording apparatus according to configuration 1, wherein the small transport operation is performed in parallel with the interrupt operation. (Configuration 5) 2. The recording apparatus according to configuration 1, wherein the interrupt operation is performed between the first small-transport operation and the second small-transport operation. (Configuration 6) 6. The recording apparatus according to any one of configurations 1 to 5, wherein the interrupt operation is a wiping operation for wiping a discharge surface on which nozzles of the recording head are provided. (Configuration 7) 6. The recording apparatus according to any one of configurations 1 to 5, wherein the interrupt operation is a suction operation for sucking the nozzles of the recording head. (Configuration 8) 6. The recording apparatus according to any one of configurations 1 to 5, wherein the interrupt operation is a preliminary ejection operation for preliminary ejection of ink from the recording head. (Configuration 9) The recording device according to any one of configurations 1 to 8, wherein the recording head ejects a plurality of inks including color inks containing color materials and a reaction liquid containing a component that insolubilizes or aggregates the color materials of the color inks. (Configuration 10) 10. The recording apparatus according to any one of configurations 1 to 9, wherein the recording medium has a property of not absorbing the liquid component of the ink. (Configuration 11) The recording device according to any one of configurations 1 to 10, wherein the drying means comprises a jet section in which the outlet is provided, and a parallel flow section that is provided upstream of the jet section in the second direction and causes gas to flow along the surface of the recording medium onto which the ink is ejected. (Method 1) a recording head that ejects ink while moving relative to a recording medium in a first direction; a conveying means for conveying the recording medium in a second direction intersecting the first direction; a drying means having a plurality of blowout ports arranged in the second direction and configured to blow jets of gas from the blowout ports toward a surface of the recording medium onto which the ink has been ejected; and A recording method for recording an image on a recording medium by alternately performing a main scan in which the recording head ejects ink onto the recording medium and a sub scan in which the conveying means conveys the recording medium a specified conveyance distance, the method comprising: a step of performing a predetermined interrupt operation between a first main scan and a subsequent second main scan; When the interrupt operation is performed, a step of conveying the recording medium by the specified conveyance distance in a small conveyance operation including a first small conveyance operation and a subsequent second small conveyance operation by the conveyance means; and A recording method characterized in that the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing between the multiple air outlets in the second direction so that the part of the recording medium facing the air outlet after the first small transport operation is not positioned in a position facing the air outlet after the second small transport operation is performed. [Explanation of symbols]

[0126] 1: recording device, 101: recording head, 102: recording head, 108: pair of conveying rollers, 110: maintenance mechanism, 201: heating and drying mechanism, 607: recording control section, 612: conveying motor, 902: jet hole

Claims

1. a recording head that ejects ink while moving relative to a recording medium in a first direction; a conveying means for conveying the recording medium in a second direction intersecting the first direction; a drying means having a plurality of nozzles arranged in the second direction, and configured to blow jets of gas from the nozzles toward a surface of the recording medium onto which the ink has been ejected; a control means for alternately performing a main scan in which the recording head ejects ink onto the recording medium and a sub scan in which the conveying means conveys the recording medium a specified conveyance distance; A recording device comprising: when a predetermined interrupt operation is performed between a first main scan and a subsequent second main scan, the control means carries out a small-conveying operation including a first small-conveying operation and a subsequent second small-conveying operation by the conveying means to convey the recording medium by the specified conveying amount, A recording device characterized in that the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing between the multiple air outlets in the second direction so that the part of the recording medium facing the air outlet after the first small transport operation is not positioned in a position facing the air outlet after the second small transport operation is performed.

2. 2. The recording apparatus according to claim 1, wherein the control means performs the first small transport operation and the second small transport operation with an interval therebetween.

3. A recording device as described in claim 1 or 2, wherein the transport amounts of the first small transport operation and the second small transport operation are determined so that the portion of the recording medium that stops facing the air outlet after performing the first small transport operation is not located at a position where the recording medium stops facing the air outlet after performing the second small transport operation.

4. 3. The recording apparatus according to claim 1, wherein the small transport operation is performed in parallel with the interrupt operation.

5. 3. The recording apparatus according to claim 1, wherein the interrupt operation is performed between the first small transport operation and the second small transport operation.

6. 3. The recording apparatus according to claim 1, wherein the interrupt operation is a wiping operation for wiping a nozzle surface of the recording head on which the nozzles are provided.

7. 3. The recording apparatus according to claim 1, wherein the interrupt operation is a suction operation for sucking the nozzles of the recording head.

8. 3. The printing apparatus according to claim 1, wherein the interrupt operation is a preliminary ejection operation for preliminary ejection of ink from the print head.

9. 3. The recording apparatus according to claim 1, wherein the recording head ejects a plurality of inks including color inks containing coloring materials and a reaction liquid containing a component that insolubilizes or aggregates the coloring materials of the color inks.

10. 3. The recording apparatus according to claim 1, wherein the recording medium has a property of not absorbing a liquid component of ink.

11. 3. The recording apparatus according to claim 1, wherein the drying means comprises a jet section in which the outlet is provided, and a parallel flow section provided upstream of the jet section in the second direction and causing gas to flow along the surface of the recording medium onto which the ink is ejected.

12. a recording head that ejects ink while moving relative to a recording medium in a first direction; a conveying means for conveying the recording medium in a second direction intersecting the first direction; a drying means having a plurality of nozzles arranged in the second direction, and configured to blow jets of gas from the nozzles toward a surface of the recording medium onto which the ink has been ejected; and A recording method for recording an image on a recording medium by alternately performing a main scan in which the recording head ejects ink onto the recording medium and a sub scan in which the conveying means conveys the recording medium a specified conveyance distance, the method comprising: a step of performing a predetermined interrupt operation between a first main scan and a subsequent second main scan; a step of conveying the recording medium by the specified conveyance distance in a small conveyance operation including a first small conveyance operation and a subsequent second small conveyance operation by the conveyance means when the interrupt operation is performed; and A recording method characterized in that the transport amounts of the first small transport operation and the second small transport operation are determined based on the spacing between the multiple air outlets in the second direction so that the part of the recording medium facing the air outlet after the first small transport operation is not positioned in a position facing the air outlet after the second small transport operation is performed.

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