JP2008055839A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed, high-quality recording device by preventing occurrence of image degradation due to the transfer of a stain in the downstream side even if recording paper while conveyed at the time of paper feeding, is brought into contact with a forcing member to generate the stain, in a recording device using a recording head of a full multi-type in which a plurality of head chips are arranged in the direction of a recording element sequence. <P>SOLUTION: In the recording device, a projection member 2 is formed between a plurality of recording heads aligned in a row, and a movement means, which is provided on the downstream side of the long head in the moving direction of a recording medium, is arranged in a position which does not overlap in the row direction with a pressing means. As a result, the stain transferred by the pressing means is not transferred again by the movement means, and images without degradation are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  According to the present invention, a plurality of recording elements are arranged in a line, and a plurality of recording element substrates each having one or a plurality of columns are arranged in the column direction, and a long recording head is used in the column direction. In a recording apparatus that forms an image by driving the recording head while relatively moving the recording medium in a direction perpendicular to the recording medium and applying ink to the recording medium, the recording element surface is prevented from being damaged and caused by contamination. The present invention relates to a configuration of a recording apparatus capable of preventing image deterioration.

  Printing devices (recording devices) used in printers, copiers, etc., or recording devices used as output devices such as composite electronic devices including computers and word processors and workstations, are based on print information (recording information). An image (including characters and symbols) is printed (image recording) on a recording medium such as a plastic thin plate. Such printing apparatuses can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a printing method.

  In a so-called serial type printing apparatus that performs printing while scanning in a main scanning direction that intersects a conveyance direction (sub-scanning direction) of a recording medium, a recording head (printing head) as a printing unit that moves along the recording medium ) To record an image. That is, every time the printing operation for one main scan is completed by the recording head, the recording medium is conveyed by a predetermined amount, thereby printing the entire recording medium.

  On the other hand, in a so-called line type printing apparatus that involves only movement of the recording medium in the conveyance direction during the printing operation, the recording medium is set at a predetermined position, and the printing operation for one line is performed while conveying the recording medium. By performing it continuously, printing is performed on the entire recording medium.

  Among each type of printing apparatus, an ink jet printing apparatus (ink jet recording apparatus) uses an ink jet recording head (ink jet print head) as a printing means, and ejects ink from the recording head's ejection port toward a recording medium. And printing. This ink jet printing apparatus is easy to downsize the recording head, can form high-definition images at high speed, can print on so-called plain paper without requiring special processing, and has low running cost. In addition, the non-impact method has advantages such as low noise, and the ease of adopting a configuration for forming a color image using multicolor ink. Furthermore, in this type of printing apparatus, that is, a recording head (so-called full multi-type recording head) in which a large number of inkjet recording elements are arranged in a direction intersecting (generally orthogonal) with the conveyance direction of the recording medium. In the line printer type using this, image formation can be further speeded up, and the possibility as a printer for on-demand recording, which has recently been increasing in demand, has been attracting attention. The ink jet recording element is positioned over the entire width of the recording area of the recording medium, and is configured to eject ink from the ejection port.

In this case, an increase in the size of the chip constituting the recording element of the recording head is expected. When the chip size is increased, the exposure of the recording element surface is increased, and the possibility that the recording paper comes into contact with the recording element surface due to corner breakage or jamming of the recording sheet increases. As a result, the recording element surface is damaged, resulting in ejection failure. (See Figure 3)
As a measure for preventing damage to the recording element surface due to such a jam of the recording paper, it is common to provide a nozzle cover for covering the outer periphery of the chip shown in FIG. It has been difficult to completely prevent the recording element surface from being damaged by the recording paper.

  For this purpose, a head having an inclination or a protrusion with respect to the mask surface described in JP-A-5-338160, a head having a recording element surface as a recess described in JP-A-4-35054, -78056, a head with a cover for preventing ink from entering, and a head for preventing damage by providing a crosspiece at the opening described in JP-A-2002-67345. It has already been proposed.

  Further, in a full multi-type recording head in which a plurality of recording elements are arranged in the width direction by arranging a plurality of chips in the recording element array direction, the chips arranged in a staggered pattern as shown in FIG. There is already a configuration in which a recording paper is pressed against the platen by providing a pressing means such as a spur to prevent damage caused by the recording paper even in a full multi-type recording head that is larger than a normal recording head.

In this configuration, it is possible to cope with a high-speed and high-quality recording apparatus using continuous paper such as roll paper, and pressing means arranged on each nozzle row even when a recording paper having a curled shape is fed. The sheet is nipped by the downstream conveying roller and discharged.
JP-A-5-338160 Japanese Patent Laid-Open No. 4-235054 Japanese Patent Laid-Open No. 11-78056 JP 2002-67345 A

  However, even with the above-described configuration, various problems have arisen in recent years with the demand for higher image quality.

  One of the demands is to reduce the distance between recording sheets (0.5 to 1.0 mm) in order to improve ink landing accuracy. FIG. 2 is a graph showing the height of the leading edge depending on the paper type. The horizontal axis indicates the free length (mm) from the nip to the leading edge with one side nipped by a roller, and the vertical axis indicates the height. The demand for roll paper is strong due to the recent demands for higher speed, higher image quality, and borderless printing such as photos, and the graph shows the results of measuring three types of roll paper. It can be seen that in order to avoid contact, it is necessary to provide pressing means at intervals of 10 mm to 20 mm in the transport direction.

  On the other hand, in order to increase the resolution in the nozzle direction, the width of the chip in the conveyance direction is increased. As a result, the width of the entire recording head is increased, and in the embodiment, the width is 50 mm. As a result, there is a problem that in order to avoid contact, it is necessary to hold down at least three pieces in the conveying direction, but the arrangement cannot be made.

  If it is intentionally placed, the dilemma will be further increased, and it will become more susceptible to the curl of the recording paper.

  In particular, when the roll paper is conveyed, one-side conveyance is performed by the upstream-side conveyance roller at the time of paper supply, and after passing under the head, the both-side conveyance state with the downstream-side conveyance roller is achieved. By controlling the upstream and downstream transport rollers in both-side transport, it is possible to suppress the lift directly under the head, and it is easy to maintain a stable distance between the recording element and the recording paper, and to obtain high image quality. Although this is an advantageous recording method because it can be performed, in the state of one-side transport during paper feeding, a problem arises because a large float occurs due to the curl.

  Furthermore, even if a spur, which is a rotating body, is used for the pressing member or the like to prevent transfer, ink mist adheres to the recording element surface due to the narrowing of the interval between the recording paper and the recording element, and transfer occurs over time. I can easily imagine that.

  An object of the present invention is a device that records on continuous paper such as roll paper using a full multi-type recording head, and when the recording paper is transported at the time of paper feeding and is in contact with the pressing member and is contaminated. Another object of the present invention is to provide a recording apparatus in which image deterioration due to transfer of dirt does not occur on the downstream side.

  In order to achieve the above object, the recording apparatus of the present invention provides a long recording in the column direction in which a plurality of recording elements are arranged in a line and a plurality of recording element substrates each having one or more columns are arranged in the column direction. In a recording apparatus for forming an image by driving a recording head while relatively moving a recording medium in a direction orthogonal to the column of recording elements using a head, and applying ink to the recording medium. A convex member is provided between a plurality of recording heads arranged in a line, and the moving means provided on the downstream side of the long head in the recording medium moving direction is arranged at a position that does not overlap the pressing means in the row direction. Thus, an image without deterioration can be obtained by not transferring again the dirt transferred by the pressing means by the moving means.

  Further, since the pressing means is constituted by a rotating body and rotates following the movement of the recording medium, the occurrence of transfer itself by the pressing means can be suppressed.

  Further, since the rotating body is constituted by a spur, the contact area on the surface of the recording paper can be reduced, and the occurrence of contamination due to transfer can be prevented.

  In the case where a plurality of the full multi-type recording heads are arranged in the scanning direction, and the overlapping portions of the recording elements are arranged arbitrarily shifted in the nozzle direction so as not to overlap each recording head, the recording heads By disposing the moving means provided on the downstream side at a position that does not overlap the pressing member in the row direction, it is possible to provide a high-speed and high-quality recording apparatus that is not deteriorated by transfer.

  In addition, the recording medium is continuous paper, and high-speed conveyance with a constant distance between the recording medium and the recording element can be performed at high speed and high image quality.

  According to the present invention, in a recording apparatus using a full multi-type recording head in which a plurality of head chips are arranged in the direction of the recording element array, the recording paper is transported during feeding, and contamination occurs due to contact with the pressing member. Even in this case, it is possible to provide a high-speed and high-quality recording apparatus by preventing the transfer of dirt from occurring downstream.

(Example 1)
The first embodiment of the present invention will be described below.

  In the embodiment described below, a recording apparatus using a full line head will be described as an example of a printer.

  FIG. 2 is a cross-sectional view of the image forming apparatus according to the present invention in FIG. 1.

  In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and figures, but also for human beings, regardless of whether it is significant or not. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” means not only paper used in general recording apparatuses but also a wide range of materials that can accept ink, such as cloth, plastic, metal plate, glass, ceramics, wood, leather, etc. To do.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “recording (printing)” above. It represents a liquid that can be used to form a pattern or the like, process a recording medium, or process an ink (for example, solidification or insolubilization of a colorant in ink applied to the recording medium).

  First, the conveyance of the recording paper will be described from the paper supply side. The roll paper P is held by the feed rotating body 22 and abuts on a roll paper reference guide 25 located on the back side of the main body, and is regulated and fixed in the thrust direction by the roll paper movement guide 24 from the front side. Then, the roll paper P fed from the feed rotating body 22 is swung by the loop detection flag 29 and guided to a guide regulated by the reference regulation guide 15 and the movement regulation guide 16 in the nozzle row direction perpendicular to the conveyance direction. It is burned.

  The loop detection flag 29 is movable in the direction of the arrow shown in the figure, and a constant tension is applied to the roll paper P in the transport direction. When the roll paper P is transported and the loop amount decreases, the loop detection flag 29 is The sensor is detected by swinging, the feed rotating body 22 is rotated, and the roll paper P is conveyed in the direction of the regulation guides 15 and 16. As a result, the loop amount increases, the loop detection flag 29 returns to the original position, the detection is released, the feed rotating body 22 is stopped, and a constant tension is maintained again. By repeating this operation during the transport operation, the recording paper is transported while the tension on the upstream side of the registration roller 31 is stably generated.

  The roll paper P positioned in the nozzle row direction perpendicular to the conveyance direction by the regulation reference guide 15 is conveyed to the nip portion of the registration roller 31 and applies a certain conveyance force to the registration roller 31 and the pressure applied thereto. The paper is conveyed to a recording area by a driven roller 32 that rotates while rotating.

  In the print area, a plurality of full multi-type recording heads 7 in which a number of nozzles are provided in a direction orthogonal to the transport direction to fly ink are arranged in the transport direction, and the upstream side of each recording head 7, On the downstream side, a transport roller 35 is provided on the back side sandwiching the roll paper and the upper roller 34 for suppressing the roll paper from floating. As a result, the interval between the recording head 7 and the roll paper P is narrowed (about 0.6 mm), and high-definition images are made possible by reducing the deviation of landing due to flying.

  Also, the four recording heads 7 shown in the figure are fixed to the upper and lower head frames 6 and are arranged at a certain distance from the roll paper P during printing, and during the storage and head recovery operations, the upper and lower head frames 6 are arranged. Moves up and down. The vertical movement may be performed by pulse control (not shown) using a stepping motor, or a height reference is provided and the vertical head frame 6 is abutted so that the height is always constant. There may be.

  In the print area, the roll paper P on which a high-definition image is formed is conveyed by the drive roller 33 and the upper roller 34, and is conveyed to the cutter area as a subsequent process. In the cutter area, the roll paper P, which is continuously transported, is stopped during the cutting operation, and after completion, it is transported at a high speed at about 3 times the transport speed and repeatedly moved to the next cutting position. The cutting operation is performed to a certain length. For this reason, since the cutter area is intermittently fed, a loop area is provided, and while the roll paper is stopped during the cutter operation, the continuously fed portion is looped to stay. The cut roll paper P is discharged from the cutter area, and a series of printing operations is completed.

  Next, the paper feed state of the roll paper at the time of paper feed will be described with reference to FIGS.

  As described above, when the roll paper is conveyed by a pair of rollers, the height increases as the free length increases as the paper is fed from the rollers as shown in the graph of the tip height of the paper type shown in FIG. Incidentally, in this apparatus, the distance between the nozzle and the recording paper is 0.6 mm, and in this case, it comes into contact with the recording element surface with a free length of about 10 mm.

FIG. 3 is a simplified cross-sectional view of a full multi-type recording head 7 having two rows of recording elements 4 in the transport direction, and shows the state of the leading edge of the roll paper during paper feeding. As described above, the leading edge of the roll paper P that has passed through the nip between the upstream-side transport roller 35a and the upper roller 34a is transported by a pair of rollers immediately below the recording head 7. As a result, as described above, the free length is about 10 mm, and when the leading end of the roll paper is sent out, it comes into contact with the recording element surface of the recording head 7. (Figure below)
Therefore, as shown in FIG. 4, a convex member as pressing means is provided on the recording element surface so that the convex member is always brought into contact with the recording element surface. In this apparatus, the gap between the recording element and the recording paper is 0.6 mm, and the convex member is set to a height of 0.2 mm from the recording element surface.

  In FIG. 5 (a), a fluororesin is pasted as a convex member, and a chip having a chip located thereon is arranged using a material having good sliding properties with recording paper and chemical resistance with ink. Arranged in a reverse staggered pattern at no position. By forming in this way, it is possible to form a convex portion with a free shape, and it is possible to cope with heads of various shapes and sizes.

  FIG. 5B shows a staggered arrangement of the spurs described in the prior art as convex members, which is advantageous in consideration of transfer due to the occurrence of dirt over time. It is effective as long as placement is allowed. However, when recording on high-quality paper such as photographs, there is a problem that the surface is scratched or the surface of the recording paper is soft and easily damaged.

  FIG. 5C shows a structure in which convex members are provided at both ends of each chip arranged in a staggered pattern. Originally there is a connection part for wiring to the chip, and epoxy resin is used as a sealing material to cover that part, and the convex height is controlled by optimizing the viscosity of this part The structure is used as pressing means.

  FIG. 4 shows the state of the leading end when roll paper is fed in these configurations. When the height of the leading end of the roll paper conveyed by the nip between the conveying roller 35a and the upper roller 34a located on the upstream side of the recording head 7 increases as the free length increases, it protrudes ahead of the recording element surface of the recording head 7. It will come into contact with the member. At this time, in the ink jet, a recovery operation such as cleaning is performed before the recording operation, and the vicinity of the recording element is in a clean state. It is conceivable that the ink remains. This remaining ink amount is larger per unit area than the landing amount due to ejection, so when contacting the recording paper, all the ink cannot be absorbed or it takes time, and there is a problem in this proposal downstream. As a result, image deterioration due to transfer occurs.

  However, when feeding the leading edge of the roll paper in a gap of 0.6 mm for pressing on the convex member, the recording element can be conveyed without being damaged. A narrow gap between the recording head and the platen is conveyed by being pressed by a plurality of convex members (two locations in the figure) in the conveying direction, and reaches the downstream conveying roller 35b and the upper roller 34a, and then the upstream roller pair By controlling the feed amount with the pair of downstream rollers, a constant tension is generated in the roll paper, and it becomes possible to stably convey between the narrow gaps of 0.6 mm. Then, recording is performed by flying ink.

  In this embodiment, the recording head 7 has a width of 50 mm, and the distance between the upstream and downstream rollers is 75 mm. When the leading end of the roll paper reaches the downstream side and is conveyed 20 mm, the bottom of FIG. Therefore, the roll paper leading edge 100 mm is cut and discarded by the cutter located downstream as the paper feeding leading edge margin. At the tip 100 mm, a lot of stains and the like are generated due to the contact of the convex member described above, but the printed matter does not generate any stains because roll paper is used.

  Next, an embodiment of the present invention will be described with reference to FIGS. Four full multi-type recording heads 7 are arranged in the order of black, cyan, magenta, and yellow from the upstream side of the transport, and the recording paper passes directly under these heads to form a high-definition photographic image. It is a recording device that can do this.

  The recording heads are arranged so as to be shifted by about 0.2 to 1.5 mm in the nozzle row direction. This is to prevent the seam from overlapping and conspicuous on the recorded image by shifting the joint between the chips constituting the recording head. As described above, the paper is fed while being in contact with the convex member at the time of feeding the leading edge of the roll paper. However, if contact is made at the same position in the nozzle row direction at this time, color is mixed on the recording element surface and the color of the ink is changed. May change, and high image quality may not be obtained, so that the positions of the convex members do not overlap in the nozzle row direction.

  Between each recording head 7, an upper roller 34 having a plurality of divided rollers on the same axis is arranged. The material is a rubber material having water repellency. The position of the divided conveying means is the main means in the present invention, where the above-mentioned convex members are arranged, and the roll paper leading edge in consideration of the amount of displacement of each recording head in the nozzle direction. When the range in the nozzle row direction that may come into contact is the range indicated by the arrow N in FIG. 6, the divided rollers as the conveying means are arranged in the range indicated by the arrow W that does not overlap the range N.

  With this configuration, even when ink that cannot be absorbed adheres to the convex portion at the leading end of the roll paper when it is fed, and the ink is fed by each of the transport rollers, the transport rollers are not soiled. As a result, it is possible to provide a high-quality image without image quality degradation.

  According to the present invention, in a recording apparatus using a full multi-type recording head in which a plurality of head chips are arranged in the direction of the recording element array, the recording paper is transported during feeding, and contamination occurs due to contact with the pressing member. Even in this case, it is possible to provide a high-speed and high-quality recording apparatus because it is possible to prevent image deterioration due to transfer of dirt on the downstream side.

1 is a cross-sectional view of an image forming apparatus according to the present invention. Graph of measuring the tip height according to the paper type. FIG. 3 is a schematic cross-sectional view showing a state of a tip when a roll paper is fed. The schematic sectional drawing which showed the state of the front end at the time of feeding the roll paper in this invention. Sectional drawing and the bottom view which showed the form of the convex member in this invention. The bottom view which showed the arrangement structure of the convex member and conveyance means in this invention. Sectional drawing which showed the arrangement structure of the convex member and conveyance means in this invention. Sectional drawing and the bottom view which showed the form of the convex member in the conventional Example.

Explanation of symbols

P Roll paper 1 Recording device
2 Convex member
4 Recording element
5 chips
6 Upper and lower head frames
7 Recording head section 7K, 7C, 7M, 7Y Recording head
8 cap
22 Feed rotating body
23 Pressing roller spring
24 Roll paper reference guide
25 Roll paper movement guide
29 Loop detection flag
30 platen
31 Registration roller
32 Followed roller
33 Drive roller
34 Upper roller
35 Transport roller
36 Feed upstream sensor
37 Feeding downstream sensor
41 Paper discharge roller
51 Cutter unit
52 Cutter
53 Drive motor

Claims (5)

A direction in which a plurality of recording elements are arranged in a line and a plurality of recording element substrates each having one or more columns arranged in the column direction are used in a column direction and are orthogonal to the column of the recording elements. In the recording apparatus for forming an image by driving the recording head while relatively moving the recording medium and applying ink to the recording medium,
A convex member is provided between the plurality of recording heads arranged in a row, and the moving means provided on the downstream side of the long head in the recording medium moving direction is disposed at a position not overlapping the convex member in the row direction. A recording apparatus.   The recording apparatus according to claim 1, wherein the convex member is formed of a rotating body and rotates according to the movement of the recording medium.   3. The recording apparatus according to claim 2, wherein the rotating body is configured by a spur.   In the case where a plurality of the recording heads are arranged in the scanning direction, and the overlapping portions of the recording elements are arranged in the nozzle direction so as not to overlap each recording head, the recording heads are not overlapped with the convex members in the row direction. 4. The recording apparatus according to claim 1, further comprising a moving unit.   The recording apparatus according to claim 1, wherein the recording medium is continuous paper.

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