JP2005028721A - Medium transport device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of a jam or the like by obtaining suitable medium transport force depending on the thickness of the medium, in a medium transport device for transporting media of various thicknesses. <P>SOLUTION: In the medium transport device for transporting media of various thicknesses, a motion follower 8 is supported to a pull-up cover 9 in a freely swingable manner at a follower fulcrum 8b, in a position opposing a pull-up roller 7; or a lower end roller 11 is mounted at the lower end of the motion follower 8; or a roller 12 for preventing lateral shift of a sheet is mounted at the upper end of the motion follower 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transport mechanism that transports media having various thicknesses in a printer, a copying apparatus, or the like.
[0002]
[Prior art]
Configuration diagrams of a conventional medium transport mechanism are shown in FIGS. FIG. 13 is a diagram showing a configuration of a transport mechanism of a conventional medium transport device, and FIG. 14 is a configuration diagram around the pull-up mechanism 102. Conventionally, in this type of apparatus, a sheet 103 to be printed is transported by a tractor 104, wound around a platen 105, fed to a print head unit 101, and then fed into a pull-up mechanism 102 by a pull-up roller 107. The paper was being pulled out and fed.
[0003]
In the pull-up mechanism 102, the pull-up cover 109 fixed to the printer body is driven in the direction A in the drawing to press the paper 103 against the pull-up roller 107, and the paper 103 is advanced by the frictional force of the pull-up roller 107. It was.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 5-29764
[Problems to be solved by the invention]
However, in the above-described conventional medium transport mechanism, in the case of thick paper transport, the mechanism load is large in the upstream process in the transport direction. Therefore, the pull-up cover 109 and the pull-up cover 109 are pulled in order to strongly press the medium against the pull-up roller 107 to obtain a strong transport force. If the gap between the up rollers 107 is set narrow, jamming occurs due to a strong load between the pull-up cover 109 and the pull-up roller 107 in the case of thin paper conveyance, and conversely, the pull-up cover 109 and the pull-up roller 107 according to the thin paper conveyance. If the gap is set, there is a problem in that a jam occurs in the transport path because a strong transport force cannot be obtained because the friction between the pull-up cover 109 and the thick paper is generated during transport of the thick paper.
[0006]
[Means for Solving the Problems]
The present invention employs the following configuration in order to solve the above-described problems. That is, in the medium transport apparatus of the first invention, a transport unit that is provided on the transport path and transports the medium;
A transport unit guide provided so as to face the transport unit with respect to the transport path, and the swing unit guide swingably supported, and a downstream portion of the transport unit guide in the medium transport direction is supported by the transported medium. And a support portion that supports the upstream portion in the medium conveyance direction of the conveyance portion guide so as to be biased by the conveyance portion when pressed.
[0007]
In the medium carrying device of the second invention, in the medium carrying device of the first invention, a roller is provided upstream of the carrying unit guide in the medium carrying direction.
[0008]
According to a third aspect of the present invention, there is provided the medium conveying device according to the first aspect, wherein a roller exposed on the conveying path is provided downstream of the conveying portion guide in the medium conveying direction.
[0009]
According to a fourth aspect of the present invention, in the medium conveying apparatus of the first aspect, the downstream portion of the conveying portion guide in the medium conveying direction protrudes into the conveying path under its own weight.
[0010]
In the medium transport apparatus of the fifth invention, in the medium transport apparatus of the first invention, the downstream section in the medium transport direction of the transport section guide is urged by the urging member and protrudes onto the transport path.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in drawing.
[0012]
<< First Embodiment >>
The medium transport apparatus according to the first embodiment is provided with a fulcrum portion on a pull-up cover and an operating follower that can swing around the fulcrum portion by a paper transport force.
[0013]
(Constitution)
FIG. 1 is a perspective view of a medium conveying apparatus according to a first embodiment, and FIG. 2 is a sectional view of the conveying mechanism (cross-sectional view taken along line XX in FIG. 1) and FIG. 3 is a pull-up cover position in FIG. FIG. 4 is an external view seen from the upper position of the working follower, FIG. 4 is a diagram for explaining the state of the working follower according to the paper carrying state, and FIG. FIG. 7 is a perspective view of the entire printer as an example equipped with the printer.
[0014]
As shown in FIG. 2 or FIG. 3, the medium conveying apparatus according to the first embodiment is configured such that the print head 1 that performs printing and the paper 3 are sandwiched to face each other, and the platen 5 is disposed behind the platen 5. The sheet 3 is fed out by the tractor 4 disposed in the platen 5 and supplied to the platen 5. A pull-up mechanism 2 is disposed above the platen 5 for discharging and drawing the paper 3 on which printing has been performed.
[0015]
The pull-up roller 7 is arranged in parallel with the platen 5 and is supported by a frame (not shown) as shown in FIG. The pull-up cover 9 is disposed at a certain distance from the pull-up roller 7 and is supported by a frame (not shown) as shown in FIG. As shown in FIG. 4, the follower fulcrum 8 b extends from each operating follower 8 and engages with the pull-up cover 9.
[0016]
4 and 5, each operating follower 8 is attached to the pull-up cover 9 so as to be swingable in the direction of arrow C in FIG. 5 at the operating follower fulcrum 8b. The follower cam 8a is configured to be heavier than the lower end of the operation follower 8 (or the position of the operation follower fulcrum 8b may be closer to the lower end), and normally protrudes into the conveyance path 10 due to its own weight. It is trying to be in a state.
[0017]
The operation follower 8 may be urged by a spring or the like so that the follower cam 8 a at the upper end of the operation follower 8 protrudes into the conveyance path 10. Even if the medium conveying device is installed vertically or in an oblique direction, the follower cam 8a protrudes into the conveying path 10 when there is no paper 3 by adopting a configuration in which it is biased by a spring or the like. it can.
[0018]
(Operation)
With the above configuration, the medium transport apparatus of the first embodiment operates as follows. First, as shown in FIG. 2, the printing operation is performed by the print head 1 when the paper 3 fed out by the tractor 4 reaches the platen 5, and the paper 3 is further moved upward. The sheet 3 is pulled in by the up mechanism 2, transported, and discharged out of the printer.
[0019]
Of the series of printing operations described above, the pull-up operation of the paper 3 that is a feature of the present application will be described below. FIG. 5 shows a state before the paper 3 is sucked by the pull-up mechanism 2, and FIG. 6 shows that the paper 3 is sucked by the pull-up mechanism 2 and is conveyed upward by the pull-up roller 7. Indicates the state.
[0020]
As shown in FIG. 5, before the sheet 3 is drawn into the pull-up mechanism 2, the operation follower cam portion 8 a protrudes into the conveyance path 10 due to its own weight or urging, and the lower end portion of the operation follower 8 has an arrow D. The position is close to the direction.
[0021]
Then, as shown in the state of FIG. 6, when the sheet 3 is fed out and advanced by the tractor 4 and the leading end of the sheet reaches the follower cam 8a and starts to be pushed, the operation follower 8 rotates in the direction of arrow E around the follower fulcrum 8b. The lower end of the operating follower 8 moves in the direction of arrow F, and the positional relationship is such that the sheet 3 is sandwiched between the lower end of the operating follower 8 and the pull-up roller 7.
[0022]
Since the operation follower 8 operates as described above, for example, when thin paper is conveyed, the thin paper 3 weakly pushes the operation follower cam portion 8a and slightly lifts it in the direction of arrow E. Then, the lower end of the operation follower presses the paper 3 against the pull-up roller 7 with a weak pressing force. Further, when thick paper is conveyed, the thick paper 3 strongly pushes the follower cam portion 8a, so that the operation follower 8 rotates strongly in the direction of arrow E, and accordingly, the lower end portion of the operation follower 8 strongly pushes in the direction of arrow F. The paper 3 is pressed against the up roller 7 with pressure. Therefore, an appropriate pressing force can be obtained according to the thickness of the paper, and an appropriate conveying force can be obtained.
[0023]
(Effect of the first embodiment)
As described in detail above, according to the medium conveying apparatus of the first embodiment, the operation follower 8 is supported on the pull-up cover 9 by the follower fulcrum 8b so as to face the pull-up roller 7, and the operation follower is supported. 8 is configured to be swingable, so that there is no special drive source for moving the pull-up roller 7 up and down, and the sheet 3 is fed to the pull-up roller 7 with an appropriate pressing force according to the thickness of the sheet. It can be pressed and a stable conveying force can be obtained. In addition, although it does not normally occur, an appropriate pressing force can be obtained even when the thickness partially changes in a series of sheets, and a stable conveying force can be obtained.
[0024]
<< Second Embodiment >>
In the medium conveying apparatus of the second embodiment, a roller is disposed at the lower end of the operating follower 8 of the medium conveying apparatus of the first embodiment to improve the conveying force.
[0025]
(Constitution)
The configuration of the medium conveying device of the second embodiment is different from the configuration of the medium conveying device of the first embodiment in the configuration of the lower end portion of the operating follower 8 and the other is the same, and for the sake of brevity, The configuration of the lower end portion of the operating follower 8 will be mainly described.
[0026]
In the medium conveying apparatus of the second embodiment, as shown in FIGS. 8 and 9, the operating follower 8 is connected to the pull-up cover 9 and the operating follower fulcrum 8b as in the medium conveying apparatus of the first embodiment. And is swingably mounted. The lower end roller 11 is rotatably attached to the lower end portion of the operating follower 8 by a lower end roller fulcrum 11a. The configuration of the other parts is the same as that of the medium conveying apparatus of the first embodiment.
[0027]
(Operation)
With the above configuration, the medium transport apparatus of the second embodiment operates as follows. FIG. 8 shows a state before the paper 3 is sucked by the pull-up mechanism 2, and FIG. 9 shows a state where the paper 3 is sucked by the pull-up mechanism 2 and the paper 3 is conveyed upward by the pull-up roller 7. Show.
[0028]
As shown in FIG. 8, before the sheet 3 is sucked into the pull-up mechanism 2, the operating follower cam portion 8 a protrudes into the conveyance path 10 due to its own weight or urging, and thus the lower end of the lower end portion of the operating follower 8. The partial roller 11 is in a position close to the arrow D direction.
[0029]
Then, as shown in FIG. 9, when the sheet 3 is fed out and advanced by the tractor 4 and the leading end of the sheet reaches the follower cam 8a and starts to be pushed, the working follower cam portion 8a is pushed up by the sheet 3 and the arrow E with the follower fulcrum 8b as a fulcrum. Since the operation follower 8 rotates in the direction, the lower end roller 11 at the lower end of the operation follower 8 moves in the direction of arrow F, and the positional relationship is such that the sheet 3 is sandwiched between the lower end roller 11 and the pull-up roller 7.
[0030]
Since the operation follower 8 operates as described above, for example, when thin paper is conveyed, the thin paper 3 weakly pushes the operation follower cam portion 8a and slightly pushes up the operation follower 8 in the direction of arrow E. Then, the lower end roller 11 of the operation follower 8 presses the paper 3 against the pull-up roller 7 with a weak pressing force.
[0031]
When the thick paper is conveyed, the thick paper 3 strongly pushes the follower cam portion 8a, so that the operation follower 8 rotates strongly in the direction of arrow E, and accordingly, the lower end roller 11 of the operation follower 8 has a strong pressing force. The paper 3 is pressed against the pull-up roller 7.
[0032]
Therefore, an appropriate pressing force can be obtained according to the thickness of the paper, and an appropriate conveying force can be obtained. And since the lower end part of the operation follower 8 is comprised with the roller, conveyance force can be raised, without generating friction, an impact, etc. with the paper 3 and a lower end part.
[0033]
(Effect of the second embodiment)
As described in detail above, according to the medium conveying apparatus of the second embodiment, the lower end roller is attached to the lower end portion of the operating follower 8 that is swingably attached to the pull-up cover 9 at the operating follower fulcrum 8b. 11 is attached, so that in addition to the effect of the medium conveying apparatus of the first embodiment, the conveying force can be improved without generating a frictional force between the lower end portion of the operating follower 8 and the sheet 3. And the occurrence of jams can be reduced.
[0034]
<< Third Embodiment >>
In the medium conveying apparatus of the third embodiment, a roller is disposed at the upper end portion of the operating follower 8 of the medium conveying apparatus of the second embodiment to further improve the conveying force.
[0035]
(Constitution)
The configuration of the medium conveying device of the third embodiment is different from the configuration of the medium conveying device of the second embodiment in the configuration of the upper end portion of the operation follower 8, and the others are the same. The configuration of the different part will be mainly described below.
[0036]
That is, as shown in FIGS. 10 and 11, the operating follower 8 is swingably attached to the pull-up cover 9 at the operating follower fulcrum 8b. A sheet lateral misalignment prevention roller 12 is attached rotatably by a roller fulcrum 12a. The configuration of the other parts is the same as that of the medium conveying apparatus of the second embodiment.
[0037]
(Operation)
With the above configuration, the medium carrying device of the third embodiment operates as follows. FIG. 10 shows a state before the paper 3 is sucked by the pull-up mechanism 2, and FIG. 11 shows a state where the paper 3 is sucked by the pull-up mechanism 2 and the paper 3 is conveyed upward by the pull-up roller 7. Show.
[0038]
Before the sheet 3 is sucked into the pull-up mechanism 2 as in the state of FIG. 10, the operating follower cam portion 8 a and the sheet lateral displacement prevention roller 12 are protruded into the conveyance path 10 due to their own weight or urging. 8 is in a state where the lower end roller 11 at the lower end portion is in the direction of the arrow D.
[0039]
Then, as shown in FIG. 11, when the sheet 3 is fed out and advanced by the tractor 4 and reaches the operating follower cam unit 8 a and the sheet lateral displacement prevention roller 12 and starts to be pushed, the sheet 3 causes the operation follower cam unit 8 a and sheet lateral displacement prevention. Since the roller 12 is pushed up and the operation follower 8 rotates in the direction of arrow E with the follower fulcrum 8b as a fulcrum, the lower end roller 11 at the lower end of the operation follower 8 moves in the direction of arrow F, and the sheet 3 is moved to the lower end roller 11. The positional relationship is between the pull-up rollers 7. At this time, the sheet lateral displacement prevention roller 12 at the upper end portion of the operation follower 8 rotates so that the sheet 3 is appropriately brought into contact with the sheet 3 and smoothly conveyed.
[0040]
The operation of appropriately pressing the paper when the thin paper is transported or when the thick paper is transported is as described in the medium transport device of the second embodiment, but the medium transport device of the third embodiment. Then, when the sheet 3 reaches the sheet lateral displacement prevention roller 12 by the sheet lateral displacement prevention roller 12 arranged at the upper end of the operation follower 8, the leading end portion of the sheet 3 is conveyed by the sheet lateral displacement prevention roller 12 to the conveyance path 10. Since the sheet 3 is conveyed while being moderately pressed to the side, it acts to prevent the sheet 3 from coming into contact with other parts such as the operating follower cam portion 8a, and also to reliably prevent the lateral displacement of the leading end of the sheet 3. Therefore, jamming of the paper 3 can be surely prevented, and horizontal deviation of the paper 3 can also be prevented. Therefore, horizontal deviation does not occur even at a place where printing is performed by the print head 1, and high-quality printing is performed. be able to.
[0041]
In order to further prevent lateral misalignment, although not shown, a configuration may be adopted in which a roller or the like is provided in a conveyance path at a position facing the sheet lateral misalignment prevention roller 12 and the sheet 3 is sandwiched therebetween.
[0042]
(Effect of the third embodiment)
As described above in detail, according to the medium conveying apparatus of the third embodiment, the lateral displacement of the sheet is detected at the upper end of the operating follower 8 that is swingably attached to the pull-up cover 9 at the operating follower fulcrum 8b. Since the prevention roller 12 is mounted, in addition to the effect of the second embodiment, it is possible to prevent the sheet 3 from coming into contact with other parts such as the operation follower cam portion 8a, and the side of the leading end of the sheet 3 can be prevented. Since misalignment can be prevented, jamming of the paper 3 and lateral misalignment during printing can be prevented, and high-quality printing can be performed.
[0043]
<< Other modifications >>
In addition to the embodiments described above, the same functions and effects of the present invention can be obtained as embodiments of the following modifications. That is,
[0044]
(1) In the description of each embodiment, the operation follower 8 has been provided for each pull-up cover 9, but the operation follower 8 may be provided only in the pull-up covers 9 at both ends, A configuration may be adopted in which the operation followers 8 are not attached to all the pull-up covers 9, for example, the operation followers 8 are provided only in the pull-up covers 9 of the part.
[0045]
(2) In the description of each exemplary embodiment, the pull-up mechanism of the impact printer has been described. However, the present invention is also applied to a paper transport unit such as an inkjet printer, a laser printer, a passbook, or a copy apparatus. Is possible.
[0046]
(3) A rubber material or the like that generates a constant frictional force as shown in FIG. 12, for example, as shown in FIG. 12 is applied to the entire surface or a part of the lower end roller or the sheet lateral displacement prevention roller 12 in the second and third embodiments. By providing in, horizontal deviation can be prevented reliably. Alternatively, the lower end roller 11 is a roller that is not provided with a material such as rubber in order to prevent jamming of the paper 3 and does not generate friction, and a material such as rubber is provided at the front end of the paper lateral displacement prevention roller 12 to prevent lateral deviation. It is good also as a structure which prevents.
[0047]
(4) In the description of the embodiment, when the leading edge of the sheet reaches the follower cam 8a or the sheet lateral displacement prevention roller 12 and starts pushing, the operating follower 8 is moved around the follower fulcrum 8b by the force in the transport direction of the sheet 3 by the arrow E. Although the configuration and control have been described as being rotated in the direction, of course, although the configuration and control are somewhat complicated, the power source may be provided to detect the position of the sheet 3 and to control the operation follower 8 to rotate appropriately based on the position detection result. Good.
[0048]
(5) In the description of the embodiment, when the leading edge of the sheet reaches the follower cam 8a or the sheet lateral displacement prevention roller 12 and starts to push, the operating follower 8 is moved around the follower fulcrum 8b by the force in the sheet transport direction. Although described as a configuration that rotates in the E direction, the configuration is somewhat complicated in consideration of the case of conveying extremely thick paper. However, an operation follower 8 is provided as in the embodiment, and according to the thickness, The operation follower 8 and the pull-up cover 9 may be moved in directions A and B in FIG.
[0049]
【The invention's effect】
As described in detail above, according to the medium transport apparatus of the present invention, the transport unit provided on the transport path and transports the medium, and the transport unit guide provided to face the transport unit with respect to the transport path. The transport unit guide is supported in a swingable manner, and when the downstream part of the transport unit guide in the medium transport direction is pushed by the transported medium, the upstream part of the transport unit guide in the medium transport direction is biased to the transport unit. In this way, a stable conveying force can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view of a medium carrying device according to an embodiment.
FIG. 2 is a side view (XX cross-sectional view of FIG. 1) of the medium transport device transport mechanism of the first embodiment.
FIG. 3 is a side view (YY cross-sectional view of FIG. 1) of the medium transport device transport mechanism of the first embodiment.
FIG. 4 is an external view of a pull-up mechanism according to an embodiment.
FIG. 5 is an operation diagram (a) of the medium transport device pull-up mechanism according to the first embodiment.
FIG. 6 is an operation diagram (b) of the medium transport device pull-up mechanism of the first embodiment.
FIG. 7 is a perspective view of a printer equipped with a medium conveyance device.
FIG. 8A is an operation diagram (a) of a medium transport device pull-up mechanism according to a second embodiment.
FIG. 9 is an operation diagram (b) of the medium transport device pull-up mechanism according to the second embodiment.
FIG. 10 is an operation diagram (a) of a medium transport device pull-up mechanism according to a third embodiment.
FIG. 11 is an operation diagram (b) of the medium transport device pull-up mechanism of the third embodiment.
FIG. 12 is a structural example of a lower end roller and a paper misalignment roller of the embodiment.
FIG. 13 is a configuration diagram of a conventional medium transport device.
FIG. 14 is a configuration diagram of a pull-up mechanism of a conventional medium transport device.
[Explanation of symbols]
2 Pull-up mechanism 3 Paper 7 Pull-up roller 8 Active follower 8a Active follower cam 8b Active follower fulcrum 9 Pull-up cover 10 Conveyance path

Claims (5)

A transport unit provided on the transport path for transporting the medium;
A transport unit guide provided to face the transport unit with respect to the transport path;
The transport unit guide is supported in a swingable manner, and when the downstream part of the transport unit guide in the medium transport direction is pushed by the transported medium, the upstream part of the transport unit guide in the medium transport direction is attached to the transport unit. A medium conveying apparatus comprising: a supporting portion that supports the urging force. The medium conveying apparatus according to claim 1, wherein
2. A medium conveying apparatus comprising a roller provided upstream of the conveying unit guide in the medium conveying direction. The medium conveying apparatus according to claim 1, wherein
A medium conveying apparatus comprising a roller exposed on the conveying path at a downstream portion of the conveying unit guide in the medium conveying direction. The medium conveying apparatus according to claim 1, wherein
A medium conveying apparatus characterized in that a downstream portion of the conveying unit guide in the medium conveying direction protrudes into the conveying path by its own weight. The medium conveying apparatus according to claim 1, wherein
A medium conveying apparatus characterized in that a downstream portion of the conveying section guide in the medium conveying direction is urged by an urging member and protrudes onto the conveying path.

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