JP2006192814A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an image gap caused by a waving platen structure. <P>SOLUTION: Image recording is carried out to a recording medium by sequentially scanning a recording head in a direction different from a transfer direction of the recording medium. The inkjet recorder comprises: a platen which is provided at a position opposed to a scanning direction of the recording head, and which forms dents and projections by a plurality of ribs provided to extend in the same direction as the recording medium transfer direction at a face opposed to the recording head; a linear encoder adapted to adjust scales in accordance with the dents and projections and to correct a gap of ink hitting positions; and a means which reads scale information of the linear encoder and scans the recording head. The linear encoder is constituted so that intervals of the scales are not equal in accordance with the dents and projections generated between the ribs of the recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, in an inkjet recording apparatus, the influence of wrinkles and wavy deformation (hereinafter referred to as cockling) that occurs when ink is ejected onto a recording medium in order to perform stable recording is eliminated as much as possible. The distance between the surface of the recording medium and the recording head must be kept constant. In addition, it is necessary to prevent paper floating from the top of the platen toward the head even for a recording medium that has been curled due to moisture or the like.

  Therefore, in order to solve such a problem, cockling and paper floating are prevented by a mechanism that is disposed on the recording area of the ink jet recording apparatus and imparts an uneven shape to the recording medium in a direction crossing the conveyance direction of the recording medium. There are some (see, for example, Patent Document 1).

Japanese Patent No. 3432052

  However, in the configuration in which the recording medium of the above-described conventional example is provided with a concavo-convex shape (hereinafter referred to as a corrugated platen), cockling and paper floating can be prevented. The interval between the recording head and the recording medium is not constant. As a result, image displacement occurs because ink ejected at equal intervals does not land on the recording medium at equal intervals.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve image shift caused by a corrugated platen structure.

In order to achieve the above object, an ink jet recording apparatus of the present invention comprises the following arrangement.

  That is, a recording medium that performs image recording by sequentially scanning the recording head in a direction different from the conveyance direction of the recording medium, provided at a position facing the scanning direction of the recording head, and recording on a surface facing the recording head. A platen that forms irregularities with a plurality of ribs provided so as to extend in the same direction as the medium conveyance direction, a linear encoder that adjusts the scale according to the irregularities and corrects the deviation of the ink landing position, and the linear encoder It is constituted by means for reading the scale information and scanning the recording head.

  According to the present invention, even if the interval between the recording head and the recording medium is not constant due to the unevenness of the recording medium due to the corrugated platen, the linear encoder has position information matched to the unevenness unique to the corrugated platen. By scanning the recording head in accordance with the information, it is possible to correct the landing position deviation due to the non-uniform distance between the recording head and the recording medium, and to obtain a high-quality image.

Hereinafter, embodiments of the ink jet recording apparatus of the present invention will be described with reference to the drawings.
<Embodiment 1>
(1) Description of Mechanical Configuration of Inkjet Recording Device In FIG. 2, 1 is a recording head that performs recording by ejecting ink, 2 is a carriage that moves while instructing the recording head 1, and 3 is a guide that supports and guides the carriage 2. Rails 4 are support rails that support the carriage 2, 5 are guide rollers that protrude from the carriage 2 and support the carriage 2 and move on the support rails 4, and 6 are directly connected to a carriage motor (not shown) that drives the carriage 2. A timing belt 7 wound around a pulley (not shown) is a cap for protecting the discharge nozzles of the recording head 1 from being dried or dirty while the recording head 1 is waiting.

  Reference numeral 8 denotes a recording medium such as paper, and reference numeral 9 denotes a paper feed side driving roller for conveying the recording medium. Reference numeral 10 denotes a registration roller that rotates following the paper feed side drive roller 9 and is pressed against the paper feed side drive roller 9 by a biasing means (not shown) to form a pair of registration rollers 11 with the paper feed side drive roller 9. ing.

  Reference numeral 12 denotes a discharge side driving roller for discharging the recording medium 8. Reference numeral 13 denotes a paper discharge roller that is driven to rotate by the paper discharge side drive roller 12 and is pressed against the paper discharge side drive roller 12 by an urging means (not shown). Forming. The paper supply side drive roller 9 and the paper discharge side drive roller 12 are driven by a motor (not shown) through a gear train or the like.

  Reference numeral 15 denotes a platen at a position facing the recording head 1, and a plurality of ribs 16 are formed on the surface of the platen in parallel with the conveyance direction of the recording medium 8. The ribs 16 need only be arranged on the platen 15 so that the recording medium 8 can be provided with irregularities in a direction intersecting the conveyance direction of the recording medium, and at least the conveyance direction of the recording medium with respect to the platen 15. If the direction is not orthogonal to Reference numeral 18 denotes a paper pressing plate for causing the recording medium 8 to follow the platen 15, and is arranged so that the upper surface of the rib 16 of the platen 15 and the horizontal portion 20 of the paper pressing plate 18 can come into contact with each other. The paper presser plate 18 is provided with a projection 19 projecting toward the platen 15 corresponding to the recess 17 between the ribs 16 on the platen 15, and is urged toward the platen 15 by urging means (not shown). Yes. In the apparatus having the above-described configuration, the recording head 1 reciprocates on the recording medium 8 via the timing belt 6 by a motor (not shown) to perform recording by ejecting ink droplets to a predetermined position of the recording medium 8.

On the other hand, the recording medium 8 is fed to a nip position of the registration roller pair 11 by a paper feeding mechanism (not shown), and after correcting skewing, the registration medium is driven from a motor (not shown) through a gear train (not shown). By the rotation of the roller pair 11, it is conveyed to the recording position. At this time, the paper pressing plate 18 is urged and pressed in the direction of the platen 15, and the recording medium 8 becomes the apex at the rib 16 portion of the platen 15 due to the rib 16 formed on the platen 15 and the projection 19 of the paper pressing plate 18. The corrugated shape becomes a valley at the protrusion 19 portion of the paper pressing plate 18.
(2) Description of Corrugated Platen Next, the corrugated platen will be described with reference to FIG.

  FIG. 3 is an enlarged view of the cross section of FIG.

In the recording operation, the recording medium 8 that has passed through the paper pressing plate 18 becomes a peak at the rib 16 portion on the platen 15 and has a gentle undulating shape like the recording medium 8a indicated by the wavy line in FIG. In this embodiment, since the recording medium is corrugated, the effect of curling and cockling of the recording medium is corrected because the recording medium is given stiffness. Will not float.
(3) Description of Control Configuration Next, a control configuration for executing recording control of each part of the apparatus configuration will be described with reference to a block diagram shown in FIG.

  In the figure showing the control circuit, 406 is an interface for inputting a recording signal, 403 is a CPU, 402 is a program ROM for storing a control program executed by the CPU 403, and 405 is various data (supplied to the recording signal and the head). In this case, the number of print dots, the number of ink recording head replacements, and the like can be stored.

Reference numeral 404 denotes a gate array that controls supply of print data to the printhead, and also controls data transfer between the interface (406), the CPU (403), and the DRAM (405). Reference numeral 409 denotes a carriage motor (LF motor) for conveying the recording head, and reference numeral 410 denotes a conveyance motor (CR motor) for conveying the recording paper. Reference numerals 407 and 408 denote motor drivers for driving the transport motor (410) and the carriage motor (409), respectively. Reference numeral 411 denotes a linear encoder arranged in parallel with the scanning direction of the recording head, reference numeral 412 denotes an encoder sensor arranged on a carriage for reading the linear encoder 411, and reference numeral 413 denotes a recording head.
(4) Description of Linear Encoder Next, the operation using a linear encoder that corrects the irregularities of the corrugated platen will be described with reference to FIG.

  Reference numeral 101 denotes a linear encoder in which the scale interval is adjusted in accordance with the position of the rib in order to correct the unevenness of the corrugated platen of this embodiment. Reference numeral 100 is a normal linear encoder, and scales are arranged at equal intervals, and is described for comparison with the 101 linear encoder.

  Reference numeral 102 denotes a recording medium, and 103 denotes ink droplets ejected from the recording head. 104a and 104b are platen ribs, and 105 is a platen.

  Reference numeral 110 denotes a recording direction of the recording head. As shown in this figure, when recording is performed from the left to the right by the recording head, the ink droplets ejected from the recording head at the encoder position 101a are added to the moving speed of the recording head and land at the position 103a.

  The recording medium 102 is uneven by the ribs 104a and 104b. The scale 108 of the linear encoder 101 is cut finer than usual in accordance with the recessed portion 106 of the recording medium 102 with the rib 104a as the apex, and the landing positions on the recording medium 102 are kept at equal intervals.

  The scale 107 of the linear encoder 101 is rougher than usual from the most concave portion of the recording medium 102 between the ribs 104a and 104b to the apex of the rib 104b, and the landing positions on the recording medium 102 are equally spaced. Keep on.

It is the figure which showed the characteristic of this invention. It is a figure which shows the structure of the inkjet recording device which can apply this invention. It is sectional drawing of the platen which can apply this invention. It is a control block diagram of an ink jet recording apparatus to which the present invention can be applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 2 Carriage 3 Guide rail 4 Support rail 5 Guide roller 6 Timing belt 7 Cap 8 Recording medium 9 Paper feed side drive roller 10 Registration roller 11 Registration roller pair 12 Paper discharge side drive roller 13 Paper discharge roller 14 Paper discharge roller pair 15 Platen 16 Rib 17 Concave 18 Paper holding plate 19 Protrusion 402 Program ROM
403 CPU
404 Gate array 405 DRAM
406 Interface 407 Motor driver 408 Motor driver 409 Carriage motor (LF motor)
410 Conveyor motor (CR motor)
411 Linear encoder 412 Encoder sensor 413 Recording head 100 Linear encoder 101 Linear encoder 101a Encoder position 102 Recording medium 103 Ink droplet 103a Ink droplet landing position 104a Rib 104b Rib 105 Platen 106 Scale 107 Scale 108 Scale 109 Scale 110 Recording direction of recording head

Claims (3)

  A recording medium for recording an image by sequentially scanning the recording head in a direction different from the conveyance direction of the recording medium, the recording medium being provided at a position facing the scanning direction of the recording head and on a surface facing the recording head A platen that forms irregularities with a plurality of ribs provided so as to extend in the same direction as the transport direction, a linear encoder that adjusts the scale according to the irregularities and corrects the deviation of the ink landing position, and a linear encoder An ink jet recording apparatus comprising: means for reading scale information and scanning a recording head.   The inkjet recording apparatus according to claim 1, wherein the linear encoder has uneven scale intervals in accordance with the unevenness generated between the ribs of the recording medium.   2. The ink jet recording apparatus according to claim 1, wherein the linear encoder has a portion having a coarse scale interval and a dense portion in accordance with the unevenness generated between the ribs of the recording medium.

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