JP2019005959A - Inkjet recording device, inkjet recording method, and computer program - Google Patents

Abstract

To provide an inkjet recording device which enables two-sided printing to be continuously performed without interrupting the printing.SOLUTION: An inkjet recording device 100 performs recording on double sides of a print sheet P by using an aqueous ink. In surface printing, the aqueous ink is discharged from a recording head 13 to a first surface of the print sheet P. In reverse printing, the aqueous ink is discharged from the recording head 13 to a second surface of the print sheet P. In a time period after the surface printing and before the reverse printing, a liquid containing water is supplied from a liquid supply part 19 to at least a part of a supply area R1 on the second surface of the print sheet P.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ink jet recording apparatus, an ink jet recording method, and a computer program.

  When recording is performed on printing paper using water-based ink, the printing paper may be curled. For example, Patent Document 1 described later proposes to use a printing paper on which a pretreatment liquid containing a monohydric alcohol is attached in advance as a method for preventing the occurrence of curling.

JP 2009-269358 A

  However, when double-sided printing is continuously performed by the method described in Patent Document 1, monohydric alcohol may volatilize and enter the nozzles of the recording head. As a result, the stability of the water-based ink in the nozzle may be reduced.

  In general, a treatment agent for preventing the occurrence of curling tends to aggregate when mixed with water-based ink. When the treatment agent is mixed with the water-based ink in the nozzle and aggregated, the nozzle may be clogged.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an ink jet recording apparatus, an ink jet recording method, and a computer program capable of continuously performing double-sided printing without causing interruption of printing. It is.

  The ink jet recording apparatus according to the present invention performs recording on printing paper using water-based ink. Specifically, the inkjet recording apparatus according to the present invention includes a recording head that discharges the water-based ink onto the printing paper, a liquid supply unit that supplies a liquid containing water to the printing paper, the recording head, and the liquid supply. And a control unit for controlling the unit. The control unit is configured to discharge the water-based ink onto the second surface of the printing paper located on the opposite side of the first surface after the water-based ink is discharged onto the first surface of the printing paper. The recording head is controlled. The control unit supplies the liquid to at least a part of the supply region on the second surface after the water-based ink is discharged onto the first surface and before the water-based ink is discharged onto the second surface. The liquid supply unit is controlled as described above. The supply region is located at the periphery of the second surface and extends along the longitudinal direction of the printing paper.

  In the ink jet recording method according to the present invention, recording is performed on both sides of a printing paper using water-based ink. Specifically, in the ink jet recording method according to the present invention, after the water-based ink is ejected onto the first surface of the printing paper, the water-based ink is ejected onto the second surface of the printing paper positioned on the side opposite to the first surface. And after discharging the water-based ink onto the first surface and before discharging the water-based ink onto the second surface, liquid is supplied to at least a part of the supply region on the second surface. Providing. The liquid contains water. The supply region is located at the periphery of the second surface and extends along the longitudinal direction of the printing paper.

  The computer program according to the present invention causes a computer constituting an ink jet recording apparatus that records on a printing paper using water-based ink to discharge the water-based ink onto the first surface of the printing paper, And discharging the water-based ink onto the second surface after discharging the water-based ink onto the first surface, and discharging the water-based ink onto the first surface. Before supplying the liquid to at least a portion of the supply area on the second surface. The liquid contains water. The supply region is located at the periphery of the second surface and extends along the longitudinal direction of the printing paper.

  According to the present invention, double-sided printing can be continuously performed without causing interruption of printing.

1 is a diagram illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating a control system of an ink jet recording apparatus according to an embodiment of the present invention. (A)-(c) is a top view which respectively shows the 2nd surface of printing paper. 5 is a flowchart illustrating a procedure of processing performed by the ink jet recording apparatus according to an embodiment of the present invention.

  Hereinafter, an inkjet recording apparatus, an inkjet recording method, and a computer program according to embodiments of the present invention will be described in order with reference to the drawings. In the drawings, the same reference numerals represent the same or corresponding parts. The dimensional relationships such as length, width, thickness, and depth are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

[Inkjet recording apparatus]
The configuration of the ink jet recording apparatus 100 will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of an ink jet recording apparatus according to the present embodiment. In FIG. 1, the upper side in the vertical direction is denoted as Z1, and the lower side in the vertical direction is denoted as Z2. Further, the direction from Z1 to Z2 is orthogonal to the direction from X1 to X2.

  The ink jet recording apparatus 100 performs recording on the printing paper P using water-based ink. The inkjet recording apparatus 100 may be a monochrome printer or a color printer as long as double-sided printing is possible. Further, the printing paper P may be any of plain paper, copy paper, recycled paper, thin paper, thick paper, or glossy paper, for example.

  Specifically, the ink jet recording apparatus 100 includes a first transport unit 11, a recording head 13, a second transport unit 15, a paper reversing unit 17, a liquid supply unit 19, a paper feed cassette 21, and a manual feed tray 23. The discharge tray 25 and the control unit 51 are provided. Hereinafter, the configuration of the inkjet recording apparatus 100 will be specifically described.

  The first transport unit 11 transports the print paper P supplied from the paper feed cassette 21 or the manual feed tray 23 along the paper transport direction (direction from the X2 side to the X1 side) while sucking. Specifically, the first transport unit 11 includes a driving roller 111, a driven roller 113, an endless transport belt 115, and a suction unit 117. The conveyor belt 115 is rotatably stretched by a driving roller 111 and a driven roller 113. A number of suction holes are formed in the conveyor belt 115. A suction unit 117 is provided on the inner side of the transport belt 115 (the back side of the transport surface of the transport belt 115). As the driving roller 111 and the driven roller 113 rotate, the transport belt 115 rotates. Further, the suction unit 117 generates a negative pressure, so that the printing paper P is attracted to the conveyance surface of the conveyance belt 115. In this way, the printing paper P adsorbed on the transport surface of the transport belt 115 is transported along the paper transport direction.

  The recording head 13 is provided above the first transport unit 11 (more specifically, the transport surface of the transport belt 115) in the vertical direction, and applies water-based ink to one surface of the print paper P based on image data and printing conditions. To discharge. For example, the recording head 13 has a plurality of nozzles. Each of the nozzles opens at the lower surface (nozzle surface) 13A of the recording head 13, and discharges water-based ink onto one surface of the printing paper P (more specifically, the printing paper P adsorbed on the conveyance surface of the conveyance belt 115). To do. The water-based ink is accommodated in a tank included in the inkjet recording apparatus 100 and flows from the tank to the recording head 13 when necessary.

  The second transport unit 15 transports the printing paper P transported from the first transport unit 11 along the paper transport direction (direction from the X2 side to the X1 side) while adsorbing. The second transport unit 15 is configured in the same manner as the first transport unit 11 and functions in the same manner as the first transport unit 11. Specifically, the second transport unit 15 includes a driving roller 151, a driven roller 153, an endless transport belt 155, and a suction unit 157. As the driving roller 151 and the driven roller 153 rotate, the transport belt 155 rotates. Further, the suction unit 157 generates a negative pressure, so that the printing paper P is adsorbed to the conveyance surface of the conveyance belt 155. In this way, the printing paper P attracted to the transport surface of the transport belt 155 is transported along the paper transport direction.

  The water-based ink discharged onto the printing paper P is dried while the printing paper P passes through the second transport unit 15. The printing paper P that has passed through the second transport unit 15 is discharged to the discharge tray 25 or is transported to the paper reversing unit 17.

  When performing double-sided printing, the paper reversing unit 17 reverses the front and back of the printing paper P on which the water-based ink is ejected only on one side. Specifically, the paper reversing unit 17 reverses the paper transport direction of the printing paper P, so that the front and back of the printing paper P are reversed. The printing paper P that has been turned upside down by the paper reversing unit 17 is conveyed to the first conveying unit 11.

  The liquid supply unit 19 supplies a liquid containing water (hereinafter referred to as “liquid S”) to one side of the printing paper P. Preferably, the liquid supply unit 19 supplies the liquid S to the surface of the printing paper P that has become the printing surface when the paper reversing unit 17 reverses the front and back. More preferably, the liquid supply unit 19 is provided downstream of the paper reversing unit 17 in the paper transport direction.

  The water-based ink and the liquid S will be described. As the water-based ink, a well-known water-based ink can be used without particular limitation as a water-based ink used for recording on printing paper using an ink jet recording apparatus. Therefore, the aqueous ink preferably includes an aqueous medium containing water and a plurality of pigment particles dispersed in the aqueous medium.

  The liquid S may contain water, and is preferably a transparent ink. The transparent ink corresponds to an aqueous ink obtained by removing pigment particles. Therefore, the transparent ink preferably contains an aqueous medium. More preferably, the aqueous ink and the liquid S include an aqueous medium having the same composition.

  The aqueous medium preferably contains, for example, water, glycerin and / or glycol, and alcohol and / or glycol ether. If the aqueous medium contains glycerin and / or glycol, drying of the aqueous ink can be prevented, and drying of the liquid S can be prevented. If the aqueous medium contains alcohol and / or glycol ether, the permeability of the aqueous ink to the printing paper P can be enhanced, and the permeability of the liquid S to the printing paper P can be enhanced. The water contained in the aqueous medium is preferably ion exchange water.

  A control system of the inkjet recording apparatus 100 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a control system of the ink jet recording apparatus according to the present embodiment. The control system of the inkjet recording apparatus 100 includes a storage device 31, an input display unit 33, an interface 41, and a control unit 51.

  The storage device 31 is configured by a nonvolatile memory. For example, the storage device 31 is preferably a hard disk. The storage device 31 preferably stores, for example, image data for printing, a control program related to various controls, and data used in the control program. Examples of the control program include a program for controlling recording on the printing paper P (hereinafter referred to as “recording control program”). The recording control program preferably includes a liquid supply program and a recording execution program. The liquid supply program means a program for supplying the liquid S to one side of the printing paper P. The recording execution program means a program for executing recording on the printing paper P. Examples of data used in the control program include a printing area, a water-based ink discharge amount, a supply area, or a liquid S supply amount.

  The input display unit 33 includes an input unit 35 and a display unit 37. The input unit 35 receives a signal input by a user of the inkjet recording apparatus 100 (hereinafter simply referred to as “user”). The display unit 37 displays various information.

  The interface 41 can communicate with the control unit 51 and each of the storage device 31, the input display unit 33, the recording head 13, the paper reversing unit 17, the liquid supply unit 19, the first transport unit 11, and the second transport unit 15. Connect to. The interface 41 connects the control unit 51 and an external device so that they can communicate with each other. Here, “external device” means a device connected to the control unit 51 via a communication network. Examples of the communication network include the Internet or a LAN.

  The control unit 51 includes a CPU 53, a ROM 55, and a RAM 57. The CPU 53 is a processor that performs various arithmetic processes. The ROM 55 is a nonvolatile memory. The ROM 55 stores in advance a control program for causing the CPU 53 to execute various arithmetic processes. The recording control program may be stored in the ROM 55 instead of the storage device 31. The RAM 57 is a volatile memory, and more specifically, temporarily stores various arithmetic processes executed by the CPU 53. When the CPU 53 executes a control program (a control program stored in advance in the storage device 31 or the ROM 55), the control unit 51 controls the operation of the inkjet recording apparatus 100.

  The control unit 51 is configured to control recording on the printing paper P, and more specifically, is configured to control the recording head 13 and the liquid supply unit 19. The controller 51 is preferably embodied by a CPU 53 that can execute a recording control program. Further, when requesting recording on the printing paper P, the control unit 51 preferably initializes various parameters used for controlling recording on the printing paper P. Recording on the printing paper P may be requested by the user operating the input unit 35 of the input display unit 33. Recording on the printing paper P may be requested by the user operating an external device (for example, a personal computer). Examples of the time when recording on the printing paper P is requested include when the power source of the ink jet recording apparatus 100 is switched from OFF to ON, or when the ink jet recording apparatus 100 returns from the power saving mode.

  Hereinafter, the control unit 51 will be described more specifically. In the following, the surface of the printing paper P on which printing is first performed in double-sided printing will be referred to as “the first surface of the printing paper P”. The surface of the printing paper P located on the opposite side to the first surface of the printing paper P is referred to as “second surface of the printing paper P”. Printing on the first surface of the printing paper P is referred to as “front printing”. Printing on the second side of the printing paper P after front side printing is referred to as “back side printing”. In double-sided printing, after front surface printing and before back surface printing is simply referred to as “before back surface printing”. “Printing” means that recording on the printing paper P is performed by discharging water-based ink from the recording head 13 onto one surface of the printing paper P.

  When requesting double-sided printing, the control unit 51 controls the recording head 13 so that the water-based ink is discharged onto the second surface of the printing paper P after the water-based ink is discharged onto the first surface of the printing paper P. It is configured. More specifically, the control unit 51 may be configured to eject water-based ink based on image data and printing conditions stored in the storage device 31 or the ROM 55, or an image input from an external device. It may be configured to eject water-based ink based on data and printing conditions.

  Further, the control unit 51 is configured to control the liquid supply unit 19 so that the liquid S is supplied to at least a part of the supply region on the second surface of the printing paper P before the back side printing. The supply area is located at the peripheral edge of the second surface of the printing paper P, and more specifically, at each of both ends in the lateral direction of the second surface of the printing paper P. The supply area is a belt-like area extending along the longitudinal direction of the printing paper P. The controller 51 may be configured to continuously supply the liquid S in the longitudinal direction of the supply region, or may be configured to intermittently supply the liquid S in the longitudinal direction of the supply region. Hereinafter, supplying the liquid S to at least a part of the supply area on the second surface of the printing paper P may be simply referred to as “supplying the liquid S”.

  In general, when recording on printing paper using an ink jet recording apparatus, the use of water-based ink has been proposed from the viewpoint of reducing environmental impact. However, when recording is performed on printing paper using water-based ink, water is absorbed by the printing paper, so that the cellulose fibers contained in the printing paper are likely to swell or the intermolecular hydrogen bonds of the cellulose fibers are broken. Therefore, a curl (convex curl) that protrudes in a direction from the non-printing surface to the printing surface is likely to occur on the printing paper on which the water-based ink is discharged.

  When performing reverse surface printing on a printing paper on which convex curl has occurred, the printing paper conveyed to the first conveying unit is likely to be positioned on the upper side in the vertical direction compared to the center. For this reason, when the printing paper is conveyed to the first conveyance unit, the front end of the printing paper in the paper conveyance direction may collide with the recording head. If the recording head is damaged by the collision of the printing paper with the recording head, it may be difficult to discharge water-based ink. Therefore, printing may be interrupted (occurrence of paper feed failure: first problem). Further, when the printing paper passes through the first conveyance unit, the trailing edge of the printing paper in the paper conveyance direction may rub the nozzle surface. Thereby, the water-based ink may contaminate the nozzle surface. When the water-based ink that contaminates the nozzle surface blocks the nozzle opening, printing is interrupted (the occurrence of a paper feed failure: a first problem). In addition, water-based ink that contaminates the nozzle surface may adhere to the non-printing area of the printing paper P (occurrence of image defects: second defect).

  As a method for preventing the occurrence of the first and second problems, for example, it is conceivable to separate the nozzle surface from the conveyance surface (more specifically, the conveyance surface of the conveyance belt included in the first conveyance unit). However, this method may cause image defects. In addition, satellite droplets may be generated. When the generated satellite droplets adhere to the non-printing area of the printing paper, an image defect occurs. When the generated satellite droplet adheres to an electrical connection site in the ink jet recording apparatus, an electrical short circuit occurs.

  As another method for preventing the occurrence of the first and second problems, it is conceivable to crease the printing paper mechanically before the back side printing. However, in this method, a paper jam is likely to occur, so that a paper feed failure is likely to occur.

  On the other hand, in the ink jet recording apparatus 100, the liquid S is supplied before the back side printing. Thereby, since the water contained in the liquid S is absorbed by the supply region, the cellulose fibers contained in the printing paper P swell or the intermolecular hydrogen bonds of the cellulose fibers are broken in the supply region. Therefore, at each end in the short direction of the printing paper P, curling that protrudes in a direction from the portion of the first surface of the printing paper P on the side opposite to the supply region to the supply region is likely to occur. Therefore, in the printing paper P transported to the first transport unit 11 during back surface printing, each end in the short direction is more easily located on the lower side in the vertical direction than the inner side in the short direction. As described above, even when the back side printing is performed on the printing paper P on which the convex curl has occurred, the occurrence of the first and second problems can be prevented. Therefore, if the inkjet recording apparatus 100 is used, double-sided printing can be continuously performed without causing interruption of printing (hereinafter, this effect may be referred to as “desired effect”). For example, if the inkjet recording apparatus 100 is used, double-sided printing can be performed at high speed and continuously.

  As described above, in the ink jet recording apparatus 100, the water contained in the liquid S is absorbed by the supply region, so that a desired effect can be obtained. Therefore, unlike the case where the printing paper is mechanically creased, it is possible to prevent curling from occurring at the short-side end of the printing paper P immediately after the liquid S is supplied. Therefore, it is possible to prevent the occurrence of a paper jam during the conveyance of the printing paper P.

  When the liquid S is a transparent ink, the liquid S and the water-based ink have the same composition except for the presence or absence of pigment particles. Thereby, the liquid S shows a high affinity for the water-based ink. Therefore, even when the liquid S enters the nozzles of the recording head 13, aggregation of the liquid S due to the mixing of the liquid S and the water-based ink can be prevented. Therefore, the stability of the water-based ink in the nozzle can be ensured. Further, it is possible to effectively prevent the nozzles in the recording head 13 from clogging.

  Note that, as described above, in the printing paper P conveyed to the first conveyance unit 11 at the time of back surface printing, each end in the short direction is more easily located on the lower side in the vertical direction than the inner side in the short direction. However, the suction unit 117 sucks the printing paper P onto the transport surface of the transport belt 115 during backside printing. Therefore, even if the liquid S is supplied before the back side printing, the aqueous ink can be supplied to a desired position on the second side of the printing paper P during the back side printing. Therefore, it is possible to prevent the occurrence of image defects during backside printing.

  A supply area | region is demonstrated concretely using Fig.3 (a)-(c). FIG. 3A is a plan view showing the second surface of the printing paper P. FIG. FIG. 3B and FIG. 3C are plan views showing enlarged portions of the second surface of the printing paper P, respectively. In each of FIGS. 3A to 3C, the longitudinal direction of the printing paper P is denoted as D1, and the lateral direction of the printing paper P is denoted as D2. Moreover, in each of FIG.3 (b) and FIG.3 (c), the supply location is attached with the oblique line. Below, a supply area | region is demonstrated using Fig.3 (a). Moreover, the relationship between a supply area | region and a supply location is demonstrated using each of FIG.3 (b) and FIG.3 (c). The supply location means a location where the liquid supply unit 19 actually supplies the liquid S in the supply region.

  Preferably, as shown in FIG. 3A, the supply region R <b> 1 has a length extending from each end in the short direction of the print paper P to the inside in the short direction of the print paper P on the second surface of the print paper P. It is located at a site separated by L1 or more and length L2 or less. An example of a preferable combination of the length L1 and the length L2 is a combination in which the length L1 is 3 mm and the length L2 is 40 mm. Thereby, in the printing paper P conveyed to the 1st conveyance part 11 at the time of back surface printing, each edge part of a transversal direction is easy to be located below a perpendicular direction compared with an inner side of a transversal direction.

  Supply part R2 may be located in a part in the longitudinal direction of supply field R1. In this case, it is preferable that the liquid S is supplied to a portion including both ends in the longitudinal direction of the supply region R1 in the supply region R1. More specifically, the liquid S may be supplied to portions of the supply region R1 excluding the center in the longitudinal direction of the supply region R1 (FIG. 3B), or spaced apart from each other in the longitudinal direction of the supply region R1. It may be supplied open (FIG. 3 (c)). The supply location R2 may be located in a part of the supply region R1 in the short direction. The inventors have confirmed that a desired effect is easily obtained when the dimension W of the supply point R2 in the short direction of the printing paper P is about 25 mm. The control unit 51 controls the liquid supply unit 19 to change the position of the supply location R2 in the supply region R1. In addition, the planar shape of the supply location R2 on the second surface of the printing paper P is not limited to the shape illustrated in each of FIGS. 3B and 3C.

Hereinafter, a description will be given of items that are considered as reasons why a desired effect is easily obtained when the supply region R1 is located at the site illustrated in FIG.
Specifically, when the supply area is located in the vicinity of the short side edge of the printing paper on the second surface of the printing paper, the length between the short edge of the printing paper and the supply area (hereinafter referred to as the supply area). Simply described as “length L”) is too short. For this reason, curling may be difficult to occur at the edge of the printing paper in the short direction.

  On the other hand, when the supply area is located on the inner side in the short direction of the printing paper on the second surface of the printing paper, the length L is too long. For this reason, the mass of the portion of the printing paper located on the short side end portion of the printing paper with respect to the supply region becomes too large, and it is difficult to maintain the shape of the portion. Therefore, the first or second problem may occur.

  However, when the supply region R1 is located at the site shown in FIG. 3A, the length L is an appropriate length. Thereby, a desired effect is easily obtained.

The supply amount of the liquid S per unit area of the printing paper P is preferably 0.1 mL / m ² or more and 2.0 mL / m ² or less. Thereby, in the supply area | region R1, the swelling of the cellulose fiber contained in the printing paper P tends to occur, and the intermolecular hydrogen bond of the cellulose fiber is likely to be broken. The control unit 51 may be configured to supply the liquid S based on the supply amount of the liquid S selected by the user when requesting double-sided printing.

Hereinafter, the control unit 51 will be described more specifically.
Preferably, the control unit 51 is transporting based on the size of the printing paper P selected by the user when requesting double-sided printing or based on the position of the paper guide in the manual feed tray 23 adjusted when the user requests double-sided printing. The printing paper P is configured to determine the longitudinal direction and the short direction. Thereby, the liquid S can be accurately supplied to at least a part of the supply region R1. When the inkjet recording apparatus 100 includes a sensor that detects the size of the printing paper P, the control unit 51 determines the longitudinal direction and the short side direction of the printing paper P being conveyed based on the detection result by the sensor. It may be configured.

  Preferably, the control unit 51 controls the liquid supply unit 19 so that the liquid S is supplied to at least a part of the supply region R1 on the second surface of the printing paper P with the paper reversing unit 17 reversed. ,It is configured. Thereby, supply of the liquid S becomes easy. In addition, an appropriate time interval can be provided after the liquid S is supplied until the back surface printing starts. Therefore, when the printing paper P is transported to the first transporting part 11, the water contained in the liquid S is sufficiently absorbed by the supply region R1, so that an appropriate curl is formed at each end in the short direction of the printing paper P. Can be generated. This control can be easily realized by disposing the liquid supply unit 19 downstream of the sheet reversing unit 17 in the sheet conveyance direction.

  Preferably, the control unit 51 is configured to control the liquid supply unit 19 so that the liquid S is not supplied before surface printing. Thereby, it is possible to prevent the curling from occurring at each end in the short direction of the printing paper P before the front surface printing. Therefore, it is possible to prevent the first and second problems from occurring during surface printing. Moreover, it is preferable that the control part 51 is comprised so that the liquid S may not be supplied after back surface printing by controlling the liquid supply part 19. FIG. By disposing the liquid supply unit 19 on the downstream side in the paper transport direction from the paper reversing unit 17, these controls can be easily realized.

  Preferably, the control unit 51 controls the liquid supply unit 19 so that the water-based ink is discharged to at least a part of a predetermined printing area (hereinafter referred to as “printing area Rp”) on the first surface of the printing paper P. In this case, the liquid S is supplied. Here, the print region Rp is a portion of the first surface of the print paper P that is 3 mm or more and 40 mm or less away from at least one end in the short direction of the print paper P inward in the short direction of the print paper P. To position. As a result of experiments by the present inventors, convex curls were likely to occur on the printing paper P when water-based ink was ejected to at least a part of the printing region Rp. Therefore, it is possible to effectively prevent the first and second problems from occurring by supplying the liquid S when the water-based ink is ejected to at least a part of the print region Rp. In this case, the control unit 51 determines whether the water-based ink is ejected to at least a part of the print region Rp based on the image data stored in the storage device 31 or the ROM 55 or based on the image data input from the external device. It is preferably configured to determine whether or not.

  Preferably, the control unit 51 is configured to determine the supply condition of the liquid S based on the curl amount of the printing paper P before the back surface printing. More specifically, the control unit 51 determines the supply condition of the liquid S based not only on the print area but also on the type of water-based ink, the type of printing paper P, or the amount of water-based ink discharged during surface printing. Further, it is preferable to be configured. The supply conditions of the liquid S include the presence or absence of the supply of the liquid S, the position of the supply location R2, and the supply amount of the liquid S per unit area of the printing paper P.

  Preferably, the control unit 51 is configured to control the liquid supply unit 19 so that the liquid S is supplied in a direction parallel to the eye direction of the printing paper P. Thereby, the water contained in the liquid S is easily absorbed into the supply region R1. Therefore, in the printing paper P transported to the first transport unit 11 during back surface printing, each end in the short-side direction is likely to be positioned on the lower side in the vertical direction as compared with the inside in the short-side direction. More preferably, the control unit 51 is configured to determine the eye direction of the printing paper P based on information regarding the eye direction of the printing paper P input by the user when requesting double-sided printing.

  The liquid supply unit 19 may be, for example, a roller having the liquid S attached to the peripheral surface or a sponge impregnated with the liquid S, but is preferably a sprayer in which the liquid S is accommodated. If the liquid supply unit 19 is a sprayer, the liquid S can be supplied to a desired position even when the size of the printing paper P is changed. Further, if the liquid supply unit 19 is a sprayer, the liquid S can be supplied without sandwiching the printing paper P between predetermined members. Therefore, the part where the liquid S is not in the supply region R1 (for example, the printing paper P of the printing paper P). Adhering to the first surface) can be prevented.

  Further, the ink jet recording apparatus 100 may include a curl correction unit that is downstream of the second transport unit 15 in the paper transport direction and upstream of the paper reversing unit 17 in the paper transport direction. Even if the ink jet recording apparatus 100 includes the curl correction unit, the desired effect can be easily obtained by supplying the liquid S before the back surface printing.

  Moreover, the implementation method of the control part 51 is not limited to the above-mentioned method. For example, the control unit 51 may be embodied in cooperation with an electronic circuit and / or a program provided outside the inkjet recording apparatus 100. More specifically, the control unit 51 may be realized by a user executing or downloading a print job control program held in a predetermined server on the communication network.

[Inkjet recording method]
Hereinafter, an ink jet recording method using the ink jet recording apparatus 100 will be described. When the user requests double-sided printing, the control unit 51 executes a recording control program. Specifically, when the user requests double-sided printing, the control unit 51 sequentially performs front side printing, liquid S supply, and back side printing. When the CPU 53 executes the recording control program (the recording control program stored in the storage device 31 or the ROM 55), the front surface printing, the supply of the liquid S, and the back surface printing can be sequentially performed.

  Hereinafter, an example of the recording control program will be described with reference to FIG. FIG. 4 is a flowchart showing a preferred example of the procedure of the recording control program. When the CPU 53 executes the recording control program, the processing shown in FIG. 4 can be performed.

  Specifically, when the user requests double-sided printing, the control unit 51 performs surface printing in step S101. More specifically, first, the control unit 51 supplies the printing paper P from the paper feed cassette 21 or the manual feed tray 23 into the ink jet recording apparatus 100. Next, the control unit 51 transports the printing paper P supplied into the ink jet recording apparatus 100 to the first transport unit 11, and then attracts it to the suction unit 117. Subsequently, the control unit 51 controls the recording head 13 to discharge water-based ink from the recording head 13 to the first surface of the printing paper P (front surface printing). Subsequently, the control unit 51 transports the printing paper P on which surface printing has been performed from the first transport unit 11 to the second transport unit 15 and then transports it to the paper reversing unit 17. Then, it progresses to step S102.

  In step S <b> 102, the control unit 51 controls the paper reversing unit 17 to reverse the front and back of the printing paper P that has been printed on the front side. Thereafter, the process proceeds to step S103.

  In step S103, the control unit 51 controls the liquid supply unit 19 to supply the liquid S from the liquid supply unit 19 to at least a part of the supply region R1 on the second surface of the printing paper P. Thereafter, the process proceeds to step S104.

  In step S104, the control unit 51 performs back surface printing. More specifically, first, the control unit 51 conveys the printing paper P supplied with the liquid S to the first conveyance unit 11 and then adsorbs the printing paper P to the suction unit 117. Next, the control unit 51 controls the recording head 13 to discharge water-based ink from the recording head 13 to the second surface of the printing paper P (back surface printing). Subsequently, the control unit 51 transports the double-side printed printing paper P from the first transport unit 11 to the second transport unit 15 and then discharges it to the discharge tray 25. In this way, the process shown in FIG. 4 ends.

  Note that the process shown in FIG. 4 may include a predetermined determination step before step S103. In the predetermined determination step, the control unit 51 determines whether or not the water-based ink has been ejected to at least a part of the print region Rp in step S101. If it is determined in step S101 that the water-based ink has been ejected to at least a part of the print region Rp, if the back side printing is performed at this time, the first and second problems may occur, and the process proceeds to step S103. move on. On the other hand, if it is determined in step S101 that the water-based ink has not been ejected to at least a part of the print region Rp, it can be determined that the first and second problems are unlikely to occur even if the back surface printing is performed at this time. The process proceeds to S104.

[Computer program]
The functions related to the control of the inkjet recording apparatus 100 may be realized by a computer program (software). The computer program according to the present embodiment causes a computer constituting the inkjet recording apparatus 100 to execute a recording control program.

  The program (recording control program) executed by the control unit 51 may be stored in a computer-readable recording medium and distributed. Further, the recording control program may be held in a predetermined server on the communication network so that the user can execute or download the recording control program.

  When the recording control program includes a liquid supply program and a recording execution program, both the liquid supply program and the recording execution program may be stored in a computer-readable recording medium, or a predetermined server on a communication network May be held. Further, one of the liquid supply program and the recording execution program may be stored in a computer-readable recording medium, and the other may be held in a predetermined server on the communication network.

[Example of material contained in liquid S]
The liquid S may further contain at least one of a surfactant, a dissolution stabilizer, a humectant, and a penetrating agent, separately from the aqueous medium. If the liquid S contains a surfactant, the wettability of the liquid S with respect to the printing paper P is improved. The surfactant is preferably a nonionic surfactant, for example, preferably an acetylene glycol surfactant. The content of the surfactant in the liquid S is preferably 0.05% by mass or more and 2.00% by mass or less.

  If the liquid S contains a dissolution stabilizer, the components contained in the liquid S are easily compatible with each other, so that the dissolved state of the liquid S can be stabilized. The dissolution stabilizer is preferably at least one of 2-pyrrolidone, N-methyl-2-pyrrolidone, and γ-butyrolacton. The content of the dissolution stabilizer in the liquid S is preferably 1% by mass or more and 20% by mass or less.

  If the liquid S contains a humectant, the volatilization of the liquid component from the liquid S can be suppressed, so that the viscosity of the liquid S can be stabilized. The humectant is preferably at least one of polyalkylene glycols, alkylene glycols, and glycerin. The polyalkylene glycol is preferably polyethylene glycol or polypropylene glycol. Alkylene glycols are ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, triethylene glycol, tripropylene glycol, 1,2,6-hexanetriol, thiodiglycol, 1,3-butane. Diol or 1,5-pentanediol is preferred. The content of the humectant in the liquid S is preferably 2% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 25% by mass or less.

  If the liquid S contains a penetrant, the permeability of the liquid S to the printing paper P is improved. The penetrant is preferably hexylene glycol, 1,2-octanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, triethylene glycol mono At least one of butyl ether and diethylene glycol monobutyl ether. The content of the penetrant in the liquid S is preferably 0.5% by mass or more and 20% by mass or less.

  The liquid S is preferably a transparent ink having a composition shown in Table 1 below, for example. The transparent ink having the composition shown in Table 1 can be obtained by mixing the materials shown in Table 1 at the ratio shown in Table 1 and then pressure-filtering using a filter having a predetermined pore size (for example, 5 μm pore size). It is done.

  The ink jet recording apparatus according to the present invention can be used as, for example, a printer capable of duplex printing.

13 Recording Head 17 Paper Reversing Unit 19 Liquid Supply Unit 51 Control Unit 100 Inkjet Recording Device P Printing Paper R1 Supply Area

Claims (8)

An inkjet recording apparatus that records on a printing paper using water-based ink,
A recording head for discharging the water-based ink onto the printing paper;
A liquid supply unit for supplying a liquid containing water to the printing paper;
A control unit for controlling the recording head and the liquid supply unit;
With
The control unit is configured to discharge the water-based ink onto the second surface of the printing paper located on the opposite side of the first surface after the water-based ink is discharged onto the first surface of the printing paper. Controlling the recording head;
The control unit supplies the liquid to at least a part of the supply region on the second surface after the water-based ink is discharged onto the first surface and before the water-based ink is discharged onto the second surface. And controlling the liquid supply,
The supply region is an ink jet recording apparatus that is located at a peripheral edge of the second surface and extends along a longitudinal direction of the printing paper. A paper reversing unit for reversing the front and back of the printing paper on which the water-based ink is discharged only to the first surface of the first surface and the second surface;
2. The ink jet recording apparatus according to claim 1, wherein the control unit controls the liquid supply unit so that the liquid is supplied to a second surface of the printing paper whose front and back are reversed by the paper reversing unit.   The supply area is located in a portion of the second surface that is 3 mm or more and 40 mm or less away from each of both ends in the short direction of the printing paper inward in the short direction of the printing paper. 2. An ink jet recording apparatus according to 1. The control unit controls the liquid supply unit so that the liquid is supplied to the second surface when the water-based ink is ejected to at least a part of a predetermined printing area on the first surface,
2. The print area is located in a portion of the first surface that is 3 mm or more and 40 mm or less away from at least one end in the short direction of the print paper inward in the short direction of the print paper. The inkjet recording apparatus as described in any one of -3.   The control unit controls the liquid supply unit so that the liquid is not supplied to the second surface before the water-based ink is ejected to the first surface. The inkjet recording apparatus according to Item. The liquid is a transparent ink;
The water-based ink and the transparent ink each include an aqueous medium,
The aqueous ink further includes a plurality of pigment particles dispersed in the aqueous medium,
The inkjet recording apparatus according to claim 1, wherein the transparent ink does not include the pigment particles. An inkjet recording method for recording on both sides of a printing paper using water-based ink,
Discharging the water-based ink onto the first surface of the printing paper, and then discharging the water-based ink onto the second surface of the printing paper located on the opposite side of the first surface;
Supplying liquid to at least a portion of the supply area on the second surface after discharging the water-based ink to the first surface and before discharging the water-based ink to the second surface;
Including
The liquid contains water;
The ink jet recording method, wherein the supply region is located at a peripheral edge of the second surface and extends along a longitudinal direction of the printing paper. In a computer constituting an ink jet recording apparatus that records on printing paper using water-based ink,
Discharging the water-based ink onto the first surface of the printing paper, and then discharging the water-based ink onto the second surface of the printing paper located on the opposite side of the first surface;
Supplying liquid to at least a portion of the supply area on the second surface after discharging the water-based ink to the first surface and before discharging the water-based ink to the second surface;
And execute
The liquid contains water;
The computer program according to claim 1, wherein the supply area is located at a peripheral edge of the second surface and extends along a longitudinal direction of the printing paper.

Images