JP2004307185A - Recording medium carrier and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium carrier capable of enhancing the carriage accuracy of a recording medium, and a recorder having the recording medium carrier. <P>SOLUTION: When a recording medium to be fed onto a recording medium carrying surface 122 is sucked and carried, the carriage capacity of the recording medium is corrected according to the suction force. Since the carriage capacity of the recording medium can be maintained to be a constant value, recording of high accuracy can be performed. The suction force is operated based on the size of the recording medium. Further, the suction force is operated based on the kind of the recording medium. Still further, the suction force is operated based on the carrying position of the recording medium. Therefore, the carrying accuracy can be enhanced to cope with a case in which the suction force is possibly changed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording medium transport device that transports a recording medium and a recording device including the recording medium transport device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, an ink-jet printer, which is one of recording apparatuses, has a configuration in which, for example, a sheet, which is one of recording media, is sent to a recording unit by a sheet conveying device and recorded and sent to the outside. In such an ink-jet printer, a sheet is recorded by a recording head while being nipped and fed by a paper feed roller and a driven roller thereof, and is sent and discharged by being nipped by a discharge roller and a spur roller as a driven roller. ing.
[0003]
In an ink jet printer equipped with such a paper transport device, when an image in which a large number of ink droplets are ejected, such as a solid image, is recorded on the paper, the paper absorbs a large amount of ink and the recording is performed. Later, so-called cockling, which swells in a wave-like manner on the recording head side, may occur. When this cockling occurs and develops, the distance between the paper and the recording head becomes non-uniform, and the flying distance of ink droplets varies, resulting in uneven recording, or when the paper comes into contact with the recording head. There is a problem that it becomes dirty. Therefore, in recent years, a plurality of holes, i.e., a plurality of holes in a lattice shape, are punched at a constant pitch in the paper transport direction and a direction perpendicular to the paper transport direction, and the paper is sucked by a suction pump or the like through these holes. Ink jet printers that suppress the cockling described above have been proposed (see Patent Documents 1 and 2).
[0004]
[Patent Document 1]
JP-A-63-303781 [Patent Document 2]
JP-A-3-270 [0005]
[Problems to be solved by the invention]
In the ink jet printer including the above-described conventional suction-type paper conveyance device, the suction drag, which is the conveyance resistance of the recording medium caused by suction, due to a change in the area of the paper covering the hole, a difference in friction coefficient for each type of paper, and the like. Changes, the paper transport amount changes, and the recording accuracy may deteriorate.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described various problems, and an object of the present invention is to provide a recording medium conveyance device capable of improving the conveyance accuracy of a recording medium and a recording device including the recording medium conveyance device. Is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a recording medium transport device according to the present invention is a recording medium transport device that transports a recording medium supplied on a recording medium transport surface while adsorbing the recording medium, wherein the transport amount of the recording medium is determined by a suction drag. The correction is performed according to Accordingly, the conveyance amount of the recording medium can be always kept constant, so that highly accurate recording can be performed.
[0008]
The suction drag is calculated based on the size of the recording medium. The suction drag is calculated based on the type of the recording medium. Further, the suction drag is calculated based on a conveyance position of the recording medium. Thereby, the transport accuracy can be improved particularly in the case where the suction drag is likely to change.
[0009]
In order to achieve the above object, a recording apparatus according to the present invention is provided with each of the recording medium transport devices described above. Accordingly, it is possible to provide a recording device that has the above-described respective effects.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a side view showing a recording medium transport device according to an embodiment of the present invention. The recording medium transport apparatus 100 includes a suction unit 110 that suctions and holds a recording medium during recording, and a recording medium transport unit 150 that transports a recording medium from an upstream side to a downstream side of the suction unit 110. The suction unit 110 is disposed below the recording head 231 for recording on a recording medium with the recording medium transport path L interposed therebetween. And it is formed in the shape of a hollow box having an upper and lower two-stage configuration including an upper suction unit 120 and a lower suction force generation unit 130.
[0011]
The suction unit 120 includes a decompression chamber 121 formed therein, a plurality of suction chambers 123 formed as long rectangular recesses in the recording medium conveyance surface 122 in the conveyance direction of the recording medium, and a pressure reduction chamber 123. In order to communicate with the chamber 121, a plurality of suction holes 124 having a smaller circular cross-sectional area than the suction chamber 123 extending in the vertical direction are provided.
[0012]
FIGS. 2A and 2B are a plan view and a cross-sectional side view taken along the line AA showing the suction unit 120. The suction chamber 123 is formed such that the short side has a predetermined length and the long side has a length from the vicinity of the upstream end to the vicinity of the downstream end of the recording medium conveying surface 122. That is, the suction chambers 123 are formed so as to communicate with each other in the direction in which the recording medium is conveyed, and to line up with the partition wall 125 therebetween in a direction orthogonal to the direction in which the recording medium is conveyed. The suction holes 124 are formed on the bottom surface of the suction chamber 123 at a predetermined pitch in the recording medium conveyance direction. That is, the suction holes 124 are formed in one row for each suction chamber 123.
[0013]
The suction force generating unit 130 communicates with the decompression chamber 121 of the suction unit 120 via a communication hole 131, and has a pump 132 having a centrifugal fan inside. The pump 132 is attached to a predetermined position below the decompression chamber 121 so as to communicate with the decompression chamber 121 via the communication hole 131, and the centrifugal fan rotates during recording. The operation of the pump 132 causes a dynamic pressure loss in each suction hole 124, and the decompression chamber 121 becomes a negative pressure.
[0014]
The recording medium conveying means 150 includes a feed roller 151 for feeding the recording medium between the recording head 231 and the suction unit 110, a driven roller 152 pressed against the feed roller 151 from above, and a recording medium to the outside. A discharge roller 153 that discharges and a spur roller 154 that contacts the discharge roller 153 from above are provided. It should be noted that the discharge roller 153 and the spur roller 154 may not be provided by, for example, making the suction unit 110 movable in the discharge direction.
[0015]
As described above, the suction hole is constituted by the suction hole 124 and the suction chamber 123, and the suction hole 124 is formed by a small-diameter through-hole, thereby increasing the utilization rate of the negative pressure that can be used for the characteristics of the pump 132. In addition, by forming the suction chamber 123 as a substantially rectangular recess having a larger area than the suction hole 124, a large suction force (that is, negative pressure × area) can be generated for the recording medium.
[0016]
FIG. 3 is a diagram illustrating a relationship between a suction drag and a cumulative error of a transport amount when a different type of recording medium is transported. Here, the suction drag means suction force × the coefficient of friction between the recording medium and the recording medium transport surface. Relationship between suction drag (N) and cumulative error (%) in the transport amount when so-called plain paper, thin paper-based coated paper, thick paper-based coated paper, and backside resin-coated paper are transported as recording media, respectively. Is shown. As is apparent from the figure, the conveyance amount of the recording medium slightly decreases due to the suction drag applied to the recording medium. The rate of decrease was found to be constant in proportion to the suction drag.
[0017]
Here, the change in the suction drag occurs, for example, in the following case. When the recording medium is conveyed from the leading end, as the leading end of the recording medium advances, the area over which the recording medium covers the suction holes 124 increases, and the suction drag increases. As the leading end of the recording medium advances, the rate at which the recording medium covers the suction holes 124 increases (the aperture ratio decreases), the negative pressure in the decompression chamber 121 increases, and the increase in suction drag is further accelerated.
[0018]
When a recording medium having a different size, particularly a width, is conveyed, a wide recording medium has a large area covering the suction hole 124, and the suction drag increases. A wide recording medium has a higher ratio of covering the suction holes 124 (a smaller aperture ratio), the negative pressure in the decompression chamber 121 increases, and the increase in suction drag is further accelerated. Further, when the suction force is set separately for each type of recording medium (such as a change in the driving condition of the pump 132), the suction drag changes. In each of the above cases, by setting the conveyance amount of the recording medium in advance in consideration of the reduction rate of the conveyance amount of the recording medium, high conveyance accuracy of the recording medium can be obtained.
[0019]
The recording medium transport device 100 having such a configuration operates as follows. The feed roller 151 and the like are driven to rotate to feed the recording medium between the recording head 231 and the suction unit 110. On the other hand, the pump 132 is driven to apply a suction force to the suction hole 124 and the suction chamber 123 via the communication hole 131 and the decompression chamber 121. As a result, the recording medium is conveyed while being suction-adsorbed on the recording medium conveying surface 122.
[0020]
The conveyance amount of the recording medium at this time is corrected according to the suction drag. Specifically, first, the suction drag is calculated based on the size of the print medium and the type of the print medium, and the transport amount of the print medium is corrected based on the calculated suction drag. Next, the suction drag is calculated based on the transport position of the recording medium, and the transport amount of the recording medium is corrected based on the calculated suction drag. Accordingly, the conveyance amount of the recording medium can be always kept constant, so that highly accurate recording can be performed. Then, the recording head 231 performs recording by discharging ink droplets onto the recording medium while moving above the recording medium in the main scanning direction. Then, the discharge roller 153 and the like are driven to rotate, and the recording medium on which recording is completed is discharged to the outside.
[0021]
FIG. 4 is a perspective view showing an ink jet printer as a recording apparatus provided with the recording medium transport device 100, and FIGS. 5 to 7 are a plan view, a front view, and a side view showing a main part thereof. The ink jet printer 200 includes an automatic sheet feeding (ASF) unit 220 which is obliquely attached to a rear upper portion of a printer main body 210, a recording unit 230 built in the printer main body 210, and a recording medium transport device 100. As the recording medium, various types of paper such as OHP film, tracing paper, and postcard can be used in addition to the special paper and plain paper of the ink jet printer 200.
[0022]
The ASF unit 220 includes a tray 221 that stores the paper 1, a paper feed roller 222 that pulls out the paper 1 from the tray 221, and supplies the paper 1. The recording unit 230 includes a carriage 233 on which the recording head 231 and the ink cartridge 232 are mounted, a DC motor 235 for moving the carriage 233 along a guide shaft 234 provided in the main scanning direction, and the like. The recording head 231 has a nozzle row including a plurality of nozzles, for example, 96 nozzles for each color of cyan, magenta, yellow, light cyan, light magenta, light yellow, and black.
[0023]
The recording medium conveying device 100 conveys a recording medium from an upstream side to a downstream side of the suction unit 110, which includes an upper suction unit 120 and a lower suction force generating unit 130 that suction and hold the recording medium during recording. And a recording medium transport unit 150. The suction unit 120 includes a decompression chamber 121 formed therein, a plurality of suction chambers 123 formed as long rectangular recesses in the recording medium conveyance surface 122 in the conveyance direction of the recording medium, and a pressure reduction chamber 123. It has a plurality of suction holes 124 communicating with the chamber 121.
[0024]
The suction force generating unit 130 communicates with the decompression chamber 121 of the suction unit 120 via a communication hole 131, and has a pump 132 having a centrifugal fan inside. The pump 132 is attached to a predetermined position below the decompression chamber 121 so as to communicate with the decompression chamber 121 via the communication hole 131, and the centrifugal fan rotates during recording.
[0025]
The recording medium conveying means 150 has a feed roller 151 for feeding the recording medium between the recording head 231 and the suction unit 110, and a driven roller 152 pressed against the feed roller 151 from above. A transport control unit (not shown) corrects the transport amount of the recording medium according to the suction force, and controls the transport of the recording medium while taking the corrected transport amount into consideration. In this embodiment, there is provided a discharge roller 153 that discharges the recording medium to the outside, and a suction unit 110 that is movable in the discharge direction without the spur roller 154 that comes into contact with the discharge roller 153 from above. Although the inkjet printer 200 is used, an inkjet printer having a discharge roller 153 and a spur roller 154 may be used.
[0026]
The ink jet printer 200 having such a configuration operates as follows. When a recording command for the paper 1 stored in the tray 221 is input by a host computer or the like (not shown), the paper feed roller 222 is driven to rotate and picks up the paper 1 stored in the tray 221 one by one. Feed paper. Further, the feed roller 152 and the like are driven to rotate to feed the paper 1 between the recording head 231 and the suction unit 110.
[0027]
On the other hand, the pump 132 is driven to apply a suction force to the suction hole 124 and the suction chamber 123 via the communication hole 131 and the decompression chamber 121. Then, the sheet 1 is conveyed while being sucked and adsorbed on the recording medium conveying surface 125. In this conveyance, first, the suction drag is calculated based on the size of the recording medium and the type of the recording medium, and the conveyance amount of the recording medium is corrected based on the calculated suction drag to be controlled. Next, the suction drag is calculated based on the transport position of the recording medium, and the transport amount of the recording medium is corrected and controlled based on the calculated suction drag. Accordingly, the conveyance amount of the recording medium can be always kept constant, so that highly accurate recording can be performed.
[0028]
Then, the DC motor 235 is driven to move the carriage 233 along the guide shaft 234 via the timing belt. At this time, the recording head 231 ejects the ink supplied for each color from the ink cartridge 232 as minute ink droplets from all or a part of the plurality of nozzles onto the paper 1 according to the recording data and records. . Then, the discharge roller 153 and the like are driven to rotate, and the sheet 1 on which recording has been completed is discharged from the discharge port 201 to the outside. As described above, it is possible to obtain high recording accuracy by high conveyance accuracy regardless of the size of the recording medium, the type of the recording medium, and the transport position of the recording medium, and without requiring any special additional device.
[Brief description of the drawings]
FIG. 1 is a side view showing a recording medium transport device according to an embodiment of the present invention.
FIG. 2 is a plan view and a cross-sectional side view taken along line AA of the suction unit in FIG. 1;
FIG. 3 is a diagram illustrating a relationship between a suction drag and a cumulative error of a transport amount when a different type of recording medium is transported.
FIG. 4 is a perspective view showing an ink jet printer as a recording apparatus provided with the recording medium transport device of the present invention.
FIG. 5 is a plan view showing a main part of the ink jet printer of FIG.
FIG. 6 is a front view showing a main part of the ink jet printer of FIG. 4;
FIG. 7 is a side view showing a main part of the ink jet printer of FIG.
[Explanation of symbols]
1 paper, 100 recording medium transport device, 110 suction unit, 120 suction section, 121 decompression chamber, 122 recording medium transport surface, 123 suction chamber, 124 suction hole, 125 partition wall, 130 suction force generating section, 131 communication hole, 132 Pump, 150 recording medium conveying means, 151 feed roller, 152 driven roller, 153 discharge roller, 154 spur roller, 200 inkjet printer, 210 printer main body, 220 ASF unit, 221 tray, 222 paper feed roller, 230 recording section, 231 Recording head, 232 ink cartridge, 233 carriage, 234 guide shaft, 235 DC motor

Claims (5)

A recording medium transport device that transports a recording medium supplied onto a recording medium transport surface while adsorbing the recording medium,
A recording medium transport apparatus, wherein the transport amount of the recording medium is corrected according to a suction drag. The apparatus according to claim 1, wherein the suction drag is calculated based on a size of the recording medium. The apparatus according to claim 1, wherein the suction drag is calculated based on a type of the recording medium. The recording medium transport apparatus according to claim 1, wherein the suction drag is calculated based on a transport position of the recording medium. A recording apparatus comprising the recording medium transport device according to claim 1.

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