JP2004268417A - Recording medium carrier and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium carrier capable of preventing the forward end part of the recording medium from floating when the recording medium is carried, and to provide a recorder comprising that recording medium carrier. <P>SOLUTION: A suction hole 124 on the downstream carrying side of a recording medium carrying surface 122 has an area larger than that of a suction hole on the upstream carrying side. Since air flow increases below the forward end part of the recording medium, the recording medium is carried with the forward end part thereof being attracted to the suction hole thus preventing contamination due to contact with a recording head. <P>COPYRIGHT: (C)2004,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 having a constant area at a constant pitch, that is, a plurality of holes in a lattice shape, are punched in the sheet transport surface in a sheet transport direction and a direction orthogonal thereto, and a sheet is sucked by a suction pump or the like through these holes. Ink jet printers that suppress the cockling described above by suction 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]
Generally, paper is warped (curled) due to environmental influences such as humidity and temperature, and properties of the surface coating material. In particular, it is difficult to suck the leading end of the paper curled upward and draw it to the paper transport surface.However, due to the position setting of the paper feed roller disposed in the paper transport insertion unit in the above-described paper transport device, It is possible to press the leading end of the inserted sheet against the sheet conveying surface so as not to float. However, as the paper advances, the force for mechanically pressing the leading edge of the paper against the paper transport surface decreases, so that the leading edge of the paper becomes easier to separate from the paper transport surface. For this reason, the leading end of the raised sheet may come into contact with the recording head and become soiled.
[0006]
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 transport apparatus and a recording medium transporting apparatus capable of preventing a leading end of a recording medium from rising when transporting the recording medium. An object of the present invention is to provide a recording apparatus provided with a medium transport device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a recording medium transport device according to the present invention includes a plurality of suction holes on a recording medium transport surface, and transports the supplied recording medium while sucking the supplied recording medium. It is characterized in that the area of the suction hole on the transport downstream side on the medium transport surface is formed larger than the area of the suction hole on the upstream side of transport. This increases the amount of air flow below the leading end of the recording medium, so that the recording medium is conveyed with the leading end drawn toward the suction hole, thereby preventing contamination due to contact with the recording head. be able to.
[0008]
The suction hole is formed so that the area thereof gradually increases toward the downstream side of the conveyance. Thereby, the amount of air flow can be increased below the leading end of the recording medium without reducing the suction force.
[0009]
In order to achieve the above object, the liquid ejecting apparatus according to the present invention is characterized in that the liquid ejecting apparatus includes an ejected material conveying device having each of the above functions. Accordingly, it is possible to provide a liquid ejecting apparatus having the above-described respective effects. In order to achieve the above object, a recording apparatus according to the present invention is provided with the above-described respective transport devices. 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]
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.
[0013]
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.
[0014]
2A, 2B, and 2C are a plan view, a cross-sectional side view taken along the line AA, and a cross-sectional side view taken along the line BB showing the suction unit 120. FIG. 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.
[0015]
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. Further, as a characteristic part of the present invention, the suction hole 124 has a larger area on the downstream side of the conveyance of the recording medium. Specifically, the suction hole 124 is formed so that the area gradually increases toward the downstream side of the conveyance of the recording medium.
[0016]
Here, in a state where the recording medium is stuck to the recording medium transport surface 122 by suction, no air flow occurs below the recording medium. The magnitude of the negative pressure (static pressure) in the decompression chamber 121 is dominant in the force for maintaining this state (the suction force in the state of being in close contact). On the other hand, when the recording medium is separated from the recording medium transport surface 122, air flows below the recording medium. Then, the recording medium is drawn to the recording medium transport surface 122 by a dynamic pressure loss caused by an air flow passing between the lower surface of the recording medium and the recording medium transport surface 122.
[0017]
In the present invention, using the latter action, the leading end of the recording medium curled upward is sucked and drawn to the recording medium transport surface 122, but the effect increases as the amount of air flowing below the recording medium increases. large. The large amount of air flowing can be obtained by increasing the area of the suction hole 124. However, when the area of all the suction holes 124 is increased, the negative pressure in the decompression chamber 121 is reduced for the following reason, and the suction force is reduced. That is, the negative pressure in the decompression chamber 121 is determined by the total area of the suction holes 124 and the flow characteristics of the pump 132.
[0018]
FIG. 3 is a diagram showing the relationship between the negative pressure ΔP in the decompression chamber 121, the total area ΔS of the suction holes 124 and the flow rate Q of the pump 132, and the characteristics of the negative pressure ΔP in the decompression chamber 121 and the flow rate Q of the pump 132. is there. The negative pressure ΔP in the decompression chamber 121 is expressed by the following equation (1) based on the total area ΔS of the suction holes 124 and the flow rate Q of the pump 132.
^{ΔP = ρ (Q / ΣS)} 2/2 ··· (1)
Therefore, the intersection of the graph of the expression (1) and the characteristic graph is the negative pressure ΔP in the decompression chamber 121 determined by the suction hole 124 having the total area ΣS at that time. For example, the negative pressure in the decompression chamber 121 determined when the suction hole 124 having the total area ΣS1 is formed is ΔP1, and the negative pressure in the decompression chamber 121 determined when the suction hole 124 having the total area ΣS2 larger than the total area ΣS1 is formed. The pressure is ΔP2 smaller than ΔP1, and the negative pressure in the decompression chamber 121 determined when the suction hole 124 having the total area ΣS3 larger than the total area ΣS2 is ΔP3 smaller than ΔP2. That is, when the total area ΔS of the suction holes 124 increases, the negative pressure ΔP in the decompression chamber 121, that is, the suction force decreases. Therefore, in this case, it is important to form the suction hole 124 so as to gradually increase the area of the suction hole 124 toward the most necessary downstream side of the conveyance of the recording medium. Thus, the total area of the suction holes 124 can be reduced, so that the negative pressure in the decompression chamber 121 can be increased. Therefore, it is possible to dynamically suction and easily draw a recording medium whose tip portion is warped upward, particularly a recording medium having high rigidity.
[0019]
As described above, by forming the suction hole with the suction hole 124 and the suction chamber 123 and forming the suction hole 124 with a small-diameter through hole, the utilization rate of the negative pressure that can be used for the characteristics of the pump 132 is increased. 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 can be generated for the recording medium. Further, since the area of the suction hole 124 is formed so as to gradually increase toward the downstream side of the conveyance of the recording medium, the leading end portion of the recording medium may be drawn to the suction hole 124 even if the recording medium advances. It is maintained and transported. Therefore, it is possible to prevent the contact contamination with the recording head 231 due to the lifting of the leading end of the recording medium as in the related art.
[0020]
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. At the same time, the recording head 231 ejects ink droplets onto the recording medium and performs recording while moving above the recording medium in the main scanning direction.
[0021]
At this time, the leading end of the recording medium is conveyed while being kept attracted to the suction hole 124. Therefore, it is possible to prevent contamination due to the leading end of the recording medium rising and coming into contact with the recording head 231. 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.
[0022]
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.
[0023]
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.
[0024]
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. The suction hole 124 is formed so that the area gradually increases toward the downstream side of the recording medium conveyance over the entire surface of the recording medium conveyance surface 122. Thus, contamination due to contact with the recording head 231 in the recording medium of each size can be prevented.
[0025]
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.
[0026]
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. 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.
[0027]
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.
[0028]
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. At the same time, 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. . Since the leading end of the recording medium is conveyed while being maintained in a state of being drawn to the suction hole 124, it is possible to prevent contamination due to the leading end of the recording medium rising and coming into contact with the recording head 231. Can be. 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.
[0029]
As described above, since the leading end portion of the recording medium is conveyed while being kept attracted to the suction holes 124, the recording head 231 can be brought closer to the recording medium, and the recording accuracy can be further improved. Can be improved. In the above-described embodiment, the suction chamber 123 is formed as a rectangular recess that is long in the transport direction of the recording medium. However, the same effect can be obtained by forming the suction chamber 123 in a conventional lattice shape. The same effect can be obtained by using a suction unit provided with only the suction hole 124 without providing the suction chamber 123. In the above-described embodiment, the recording apparatus including the apparatus for conveying the recording medium has been described. However, the present invention is applicable to a liquid ejecting apparatus including an apparatus for conveying a material to be ejected, including, for example, an ink jet printer. It has the function and effect of.
[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 showing the relationship between the negative pressure in the decompression chamber, the total area of the suction holes, and the flow rate of the pump, and the characteristics of the negative pressure in the decompression chamber and the flow rate of the pump.
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 (4)

A recording medium transport device that has a plurality of suction holes on a recording medium transport surface and transports the supplied recording medium while sucking the recording medium,
A recording medium transport apparatus, wherein an area of a suction hole on a transport downstream side on the recording medium transport surface is formed larger than an area of a suction hole on a transport upstream side. The recording medium transport apparatus according to claim 1, wherein the suction hole is formed so that an area gradually increases toward a downstream side of the transport. A liquid ejecting apparatus, comprising: the ejected material conveying apparatus having the function according to claim 1. A recording apparatus comprising the transport device according to claim 1.

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