JP2007022019A - Image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording device which is an inkjet recording device, which obtains a high picture quality by applying a preparatory treatment liquid, and prevents the recorded surface from being stained by sliding contact with a head. <P>SOLUTION: A recording head is interlocked with the selection of presence/absence of the application of the preparatory treatment liquid to move vertically, and an interval between an ink discharging port arranging surface installed on the recording head and the recording surface of a recording medium can be changed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus using an ink jet recording system, and further comprising a pretreatment liquid application unit that applies a liquid for forming a good image on a recording medium as a treatment liquid before jetting recording ink.

  In recent years, many image forming apparatuses of an ink jet recording system, such as copying machines, facsimile machines, printers, etc., have been commercialized. The ink jet recording method is one of low noise non-impact recording methods in which ink is ejected and directly adhered to a printing material (paper, cloth, non-woven fabric, OHP paper, sheet material, etc.). An image forming apparatus using a head can perform high-density and high-speed recording operations.

  However, the composition of ink used in conventional ink jet recording generally comprises water as a main component and a water-soluble high-boiling solvent such as glycol that exhibits effects such as prevention of drying and prevention of clogging. Therefore, when recording on plain paper using such ink, the ink fixing property is insufficient, or non-uniformity that seems to be due to the non-uniform distribution of the filler and sizing agent on the plain paper surface. Generate an image. In addition, when trying to obtain a color image, multiple colors of ink are stacked one after the other before fixing on the paper, so that the color blurs or mixes unevenly at the boundary between different color images. In some cases, satisfactory images could not be obtained.

  Therefore, in order to improve the above-described problems, a method is disclosed in which a liquid that satisfactorily forms an image on a recording medium is applied as a pretreatment liquid before jetting the recording ink.

  For example, Patent Document 1 uses an ink composition containing at least one chemical dye agent having at least one carboxyl group and a polyvalent metal salt solution, and after applying the polyvalent metal salt solution to a recording medium, A method for obtaining a good image by applying an ink composition is disclosed.

  Patent Document 2 also discloses an image forming method and a treatment liquid and an ink composition used for obtaining a good image.

  In the embodiments of Patent Document 1 and Patent Document 2 described above, a method of applying a treatment liquid to a recording medium using a roller prior to recording by an ink jet recording head is shown.

  However, if the application of the pretreatment liquid and the ink jet recording are linked, when the ink jet recording intermittently feeds the recording medium, the pretreatment liquid is excessively applied from the application section while the recording medium is stopped, resulting in uneven coating. In other words, when a large number of types of recording media are transported, they are also applied to unnecessary recording media.

  In order to improve these problems, in Patent Document 3, the driving of the coating roller and the conveyance roller for image recording are performed in order to separate the operation in the relationship between the pretreatment liquid coating process and the subsequent inkjet recording process. A method of driving independently is disclosed.

  Further, Patent Document 4 discloses an image recording apparatus having an independent path in which the presence or absence of application can be selected for a recording medium that does not require application.

  FIG. 4 is a sectional view showing a conventional example.

In the image recording apparatus 100, the recording medium 71 has a switching claw 88 as a path switching unit immediately after the feeding by the paper feeding roller 72 is started. A route A divided by the switching claw 88 is a coating process, and B is a route without coating. The pretreatment liquid 82 is transferred to the application roller 85 by the drawing rollers 83 to 84 and applied to the recording medium. Regardless of the presence or absence of application, the recording roller 96 passes through the auxiliary roller 73, and is eventually sandwiched between the pair of transport rollers 91 and 93 and is recorded by the recording head 96 mounted on the carriage 95 between the pair of paper discharge rollers 98.
JP-A-5-202328 JP-A-61-75870 JP 2002-103583 A JP 2002-137378 A

  However, according to the conventional example, it is clearly stated that the recording is improved by performing the coating recording, but in the area where the inks of a plurality of colors have been ejected conventionally, rubbing with the recording head caused by the swelling of the recording medium. No countermeasure has been disclosed for the possibility that the recording surface stain (smear) may be further deteriorated by application.

  The present invention has been made paying attention to the above points, and is to provide an image recording apparatus for preventing recording surface contamination due to head rubbing in an ink jet recording apparatus that applies a pretreatment liquid to improve image quality. Objective.

  In order to solve the above-mentioned problems, the present invention provides an application means for applying a pretreatment liquid containing a compound that insolubilizes a colorant being recorded to a recording area of a recording medium, and the recording area to which the pretreatment liquid is applied. And an image recording unit that records an image by ejecting ink from the surface of the ink ejection port. The application unit can select whether to apply or not, and the ink can be linked to the selection of whether or not to apply. It is characterized by comprising a sheet interval changing means in which the interval between the discharge port surface and the recording medium is variable.

According to the present invention, in an image recording apparatus capable of selectively applying a processing liquid that makes recording good prior to image recording,
In an image recording apparatus capable of selectively applying a processing liquid that improves recording prior to image recording, means for varying the interval between the ink discharge port arrangement surface mounted on the recording head and the recording surface of the recording medium Thus, even if the recording medium swells due to the application of the recording medium, it is possible to prevent the recording surface from being soiled by the recording medium coming into contact with the recording head, even if the recording medium is further swollen due to the absorption of the ink.

  In addition, the recording medium can be prevented from coming into contact with the recording head by changing the distance between the ink discharge port mounting surface mounted on the recording head and the recording surface of the recording medium in conjunction with the humidity measured by the humidity measuring means. We were able to.

  Further, when the image is recorded again after the first image is recorded, the interval between the ink discharge port arrangement surface mounted on the recording head and the recording surface of the recording medium can be changed between the first time and again. Thus, it was possible to prevent the recording medium from coming into contact with the recording head.

  According to the image recording apparatus of the present invention, in conjunction with the selection of application of the pretreatment liquid, the interval between the ink discharge port arrangement surface mounted on the recording head and the recording surface of the recording medium is made variable, thereby enabling recording. This prevents the recording medium from coming into contact with the head.

  In addition, the recording medium can be prevented from coming into contact with the recording head by changing the distance between the ink discharge port mounting surface mounted on the recording head and the recording surface of the recording medium in conjunction with the humidity measured by the humidity measuring means. To do.

  Further, when the image is recorded again after the first image is recorded, the interval between the ink discharge port arrangement surface mounted on the recording head and the recording surface of the recording medium can be changed between the first time and again. This prevents the recording medium from coming into contact with the recording head.

  FIG. 1 is a cross-sectional view showing the configuration of an image recording apparatus to which an image recording method according to the present invention is applied.

  In the figure, in the image recording apparatus of the present embodiment, the first sheet feeding unit 10 and the second sheet feeding unit 60 that send out the recording medium, the image recording unit 30 that performs image formation, and the coating unit 20 that coats the pretreatment liquid are large. Separated. The image recording unit 30 and the coating unit 20 have independent conveyance paths.

  First, the first paper feed unit 10 will be described.

  The first paper feeding unit 10 feeds a recording medium to an image recording area, and a plurality of recording media 13 stacked on the pressure plate 12 are individually sent out to the image recording area by a paper feeding roller 11 (hereinafter referred to as an image recording area). This direction, including the conveyance direction during image recording, is called the forward rotation direction). The path to the LF roller 31 that performs the main conveyance of the recording medium passes through the coating unit 20 (details below) immediately after feeding, and is along the U-turn base 24. Transport in the forward direction.

  Next, the second paper feed unit 60 will be described.

  Similar to the first paper feed unit 10, the second paper feed unit 60 feeds the recording medium to the area for image recording. It is separated by a pressure plate 12 'and a paper feed roller 11'. The recording medium passes through the conveyance path 63, is guided by the conveyance guide 45, and is guided to the LF roller 31.

  The transport guide 45 is pivotally supported on the upstream side and is rotatable, and the downstream side is lightly urged upward by a spring (not shown), so that the transport from the first paper feed unit is smoothly performed, and the second feed is performed. The conveyance from the paper unit is strong in the recording medium, so that the downstream side of the conveyance guide 45 is larger than the force that is lightly urged upward, and is guided to the LF roller 31 while pushing downward.

  In addition, the application unit 20 that was in the middle of the first paper supply unit is not sent directly to the image recording area. The conveyance path along the U-turn base of the first sheet feeding unit 10 is not U-shaped but has a J-shaped conveyance path, and is not suitable for feeding thick paper such as glossy paper. ing.

  Next, the image recording unit 30 will be described.

  The main conveyance unit that performs image recording is a pair of rollers of an LF roller 31 and a pinch roller 32, and the recording medium 13 is sandwiched between the pair of rollers to generate a conveyance force during recording. A photo sensor 38 for detecting the presence or absence of a recording medium, which is a means for controlling switching of the conveyance direction of the recording medium, is installed on the immediately upstream side sandwiched between the pair of rollers. On the downstream side of the LF roller 31 is a platen 35 that maintains the flatness of the recording medium during image recording, and on the further downstream side is a discharge roller 33 and a spur 34 that are counter rollers for discharging the recording medium after recording. The discharged recording media are stacked on the paper discharge tray 39.

  The recording unit 30 is a step of realizing recording by reciprocating the recording head (sub-scanning direction) in the width direction of the recording medium (front and back direction in the drawing) while intermittently feeding the recording medium (main scanning direction), A carriage 42 on which a recording head 41 having a large number of ink jet droplet discharge nozzles is slid on a slide shaft 43 and a slide rail 44 fixed to a chassis (not shown) of the recording apparatus 1 to thereby adjust the width of the recording medium. Recording is performed while reciprocating in the direction, and an image is completed by interlocking with intermittent feeding of the recording medium by the LF roller 31.

  Next, the duplex conveyance unit 110 will be described.

  When the user's instruction is double-sided recording, the duplex transport unit 110 is in a stage before being stacked on the paper discharge tray 39, that is, after the end of recording and the rear end of the recording medium is sandwiched between the paper discharge roller 33 and the spur 34. In this state, the LF roller 31 and the paper discharge roller 33 are reversed, and the trailing edge of the paper reaches the duplex unit 110 through the conveyance guide 45. The paper is guided to the front of the paper feed roller 11 of the first paper feed unit 10 by the conveyance path 47 and the duplex roller 61. The sheet feeding roller 11 is D-cut, and the conveyance resistance is reduced to the coating unit 20 while the recording medium is being conveyed by the duplex unit 110. Thereafter, as described above, the image is transported to the image recording unit 30 and image recording is performed in the same manner as the first transport.

  Next, the coating unit 20 will be described.

  The coating unit 20 is a unit that realizes the coating process of the pretreatment liquid, and is provided in the middle of the transport path of the first paper feeding unit 10. That is, the recording medium 13 separated into one sheet by the paper feed roller 11 is sandwiched between the application roller 52 and the pressure roller 53, and the pretreatment liquid is applied by the application roller 52.

  FIG. 2 is a schematic front view for illustrating the mechanism of the coating mechanism unit 20.

  The treatment liquid holding member 51 is longer than the maximum width of the recording medium that can be recorded by the recording apparatus, the application roller 52 is longer than the treatment liquid holding member 51, and the pressure contact roller 53 is longer than the application roller 52. The processing liquid holding member 51 is filled with the processing liquid 57, and the processing liquid holding member 51 is biased by a spring 50. For this reason, even if the roller pair of the application roller 52 and the pressure roller 53 rotates, the processing liquid 57 does not leak from the processing liquid holding member 51.

  The processing liquid tank 56 stores a processing liquid 58 to be replenished to the processing liquid holding member 51. Tubes 59 and 54 are connected to both ends of the processing liquid holding member 51, the other end of the tube 59 is connected to the processing liquid 58 of the processing liquid tank 56, and the other end of the tube 54 is connected to the pump P. 55 is communicated with the atmosphere above the processing liquid 58.

  When several recording media pass through the roller pair of the application roller 52 and the pressure roller 53 and the processing liquid 57 is reduced, the processing liquid holding member 51 is made negative pressure through the tube 54 by the pump P. Through 59, the processing liquid is replenished in the B direction from the processing liquid 58. The processing liquid sucked to create the negative pressure is circulated in the B direction through the tube 55 and flows to the upper part of the processing liquid 58 communicated with the atmosphere.

  Next, the manner in which the slide shaft 43 for raising and lowering the print head 41 in FIG. 3 will be described.

  The print head 41 mounted on the carriage 42 of the image recording unit 30 has a large number of inkjet droplet discharge nozzles, and the discharge surfaces thereof are narrow in distance (between paper sheets) with the recording medium flattened along the platen 35. However, most of the recording medium swells when it contains a large amount of moisture and the like, and the recording medium on the platen 35 grows into a wavy shape while losing flatness, and is recorded by rubbing with the print head 41. Surface contamination may occur. In this embodiment, since swelling easily occurs due to the application of the pretreatment liquid, in the case of paper feeding from the first paper feeding unit 10, the print head 41 is moved upward in advance before the leading edge of the recording medium passes through the LF roller 31. It is desirable to evacuate.

  The slide shaft 43 can move up and down in a slit 48 provided in a chassis (not shown) inside both ends thereof. A shaft gear 49 is provided at both ends of the slide shaft 43, and a cam shape 49c is provided in the shaft gear 49. The cam shape 49c is configured along a cam guide portion provided in a chassis (not shown). With this cam shape 49c, the vertical position of the slide shaft 43 is made variable as shown in FIGS. The shaft gear 49 has a flag 49f, and the sensor 77 grasps the position of the shaft gear 49.

  The idler gear 46 is rotatable about a shaft 75 that protrudes from a chassis (not shown). The slide shaft 43 is not always separated from the idler gear 46 by the bias of the spring 78. Drive transmission from a motor (not shown) passes through an idler gear 46 and the shaft gear 49 rotates around the idler gear 46, while the slide shaft 43 is moved up and down in the slit 48 as shown in FIGS. When the shaft gear 49 moves up and down as shown in FIGS. 3A and 3B, the carriage 42 on which the print head 41 is mounted can be moved up and down.

  Further, the humidity is detected by a humidity sensor (not shown) mounted in the vicinity of the image recording apparatus 1, and when the humidity is low, the curl of the recording medium after applying the pretreatment liquid is large, so that the print head 41 is further mounted. It is also preferable to raise the carriage 42 to prevent the recording surface from being stained.

  Furthermore, it is also preferable to control the vertical movement of the carriage 42 on which the print head 41 is mounted in accordance with the change in the wavy shape due to curling or swelling of the recording medium, depending on the characteristics of the pretreatment liquid and the ink for forming an image. Particularly in double-sided printing, the carriage 42 carrying the print head 41 is moved up and down before printing on the back surface according to the change in the wavy shape due to curling or swelling of the recording medium by applying the pretreatment liquid on the back surface. Prevents contamination of the recording surface.

It is principal part sectional drawing of the Example of the image recording apparatus to which this invention is applied. It is a schematic front view for showing the mechanism of the application mechanism unit to which the present invention is applied. FIG. 5 is a diagram for explaining a state of raising and lowering a slide shaft 43 for raising and lowering a print head 41. It is sectional drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image recording device 10 1st paper feed unit 11 Paper feed roller 12 Pressure plate 13 Recording medium 20 Coating unit 24 U-turn base 30 Image recording unit 31 LF roller 32 Pinch roller 33 Paper discharge roller 34 Spur 35 Platen 36 Auxiliary roller pair 38 Photo Sensor 39 Paper discharge tray 41 Print head 42 Carriage 43 Slide shaft 44 Slide rail 45 Transport guide 46 Idler gear 47 Transport path 48 Slit 49 Shaft gear 49c Cam shape 49f Flag 50 Spring 51 Treatment liquid holding member 52 Application roller 53 Pressure roller 54, 55 59 Tube 57, 58 Treatment liquid 60 Second paper feeding unit

Claims (5)

Application means for applying a pretreatment liquid containing a compound that insolubilizes the colorant in the recording liquid to the recording area of the recording medium; and discharging ink from the ink discharge port surface to the recording area to which the pretreatment liquid has been applied. In an image recording apparatus having an image recording means for recording an image
The application unit can select whether or not to apply, and includes a sheet interval changing unit that can change a distance between the ink discharge port arrangement surface and the recording surface of the recording medium in conjunction with selection of application or not. An image recording apparatus.   The image recording apparatus according to claim 1, wherein the paper interval changing unit is capable of moving the image recording unit perpendicularly to a recording surface of the recording medium.   3. The interval between the ink discharge port surface and the recording medium is variable in association with the application amount of the pretreatment liquid by the application unit. Image recording device.   The paper interval changing means has a measuring means for measuring the ambient humidity at which the recording medium is recorded, and the interval between the ink discharge port surface and the recording medium is variable in conjunction with the humidity by the measuring means. The image recording apparatus according to claim 1, wherein the image recording apparatus is provided.   There are at least two or more insertion ports for inserting the recording medium into the recording apparatus, and feeding from at least one insertion port is a conveying path through the coating means, and feeding of the recording medium is from which insertion port 5. The image recording apparatus according to claim 1, wherein a distance between the ink discharge port surface and the recording medium is variable in conjunction with whether the ink is fed.

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