JP2012062172A - Printer and recording medium registering mechanism part control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high paper traveling stability by preventing the occurrence of carrying jam at carriage between a feed roller and a gate member regardless of the rigidity of carrying paper.SOLUTION: A part of the downstream side in the paper carrying direction of an upper side carrying guide 14b of a feed roller of a paper registering mechanism 1 is formed as an auxiliary guide 15 rotatable with respect to an expanding position and a narrowing position of a clearance of a paper carrying passage. A part of the upstream side in the paper carrying direction of an upper side carrying guide of a shift roller is engaged with a free end of the auxiliary guide 15 as a rotatable rotary guide 12d. When carrying the paper 9 toward the gate member 3 by feed roller pairs 4 in a state of separating shift roller pairs 2 by putting the gate member 3 in a projecting position, the auxiliary guide 15 is rotated to the position for narrowing the clearance of the paper carrying passage by the rotary guide 12d. When forming a buffer B in the paper by passing and carrying the paper 9 after making the tip of the paper 9 abut on the gate member 3, the auxiliary guide 15 is rotated with respect to the position for expanding the clearance of the paper carrying passage by the rotary guide part 12d.

Description

  The present invention relates to a printing apparatus using an image forming apparatus such as a laser printer, and more particularly to a recording medium alignment mechanism provided in a recording medium conveyance path and a control method thereof.

  2. Description of the Related Art In a printing apparatus using an image forming apparatus such as a commercial laser printer, a recording medium such as a transfer sheet stacked on a paper feeding apparatus is conveyed one by one along its conveyance path, and a photosensitive drum or a photosensitive drum is conveyed. The toner image formed on the photosensitive member such as a body belt is directly or once transferred to the intermediate transfer member, and then the paper is transferred to the transfer position to transfer the toner image, and the toner image is passed through the fixing device. Is fixed on the paper, and the image is printed on the paper.

  In such a printing apparatus, a paper alignment mechanism is provided in the paper conveyance path to the image transfer position of the printing unit, and corrects the posture of the recording medium and then conveys it to the transfer position, so that the correct position on the recording medium is obtained. The toner image is transferred to the surface.

  For example, as described in Patent Document 1, the sheet aligning mechanism unit of such a printing apparatus is positioned upstream in a state where the leading end of the sheet is abutted against a stopper (gate member) and the leading end is stopped. The paper is fed by the carrying means to form a curved buffer on the paper, and the inclination with respect to the carrying direction is corrected. Thereafter, the stopper is opened, the paper is nipped and conveyed by a pair of rollers positioned downstream of the stopper, and a direction perpendicular to the paper conveyance direction (by a detection means provided on the side near the downstream side of the stopper ( The width direction is detected from the reference position and the amount of deviation is detected, and the pair of rollers nipping the paper is moved by the detected amount of deviation in the opposite direction to the detected deviation direction. After correction, the paper is conveyed to the transfer position of the printing unit.

  An example of the sheet alignment mechanism in such a conventional printing apparatus will be described with reference to FIGS. 6 includes a shift roller pair 2, a gate member (stopper) 3, a feed roller pair 4, a detection sensor 5, and the like, and is provided between the feed roller pair 4 and the shift roller pair 2. The distance (interval in the paper conveyance direction) and the conveyance path shape are substantially straight at a distance that allows conveyance of small-size paper.

The gate member 3 is urged by a spring so that the leading end of the gate member 3 projects into the downstream sheet conveyance path immediately after the pair of shift rollers 2, and rotates between a protruding position for closing the sheet conveyance path and a retracted position for opening the sheet conveyance path. It is supported movably.
A sheet posture correction (alignment) operation in the sheet alignment mechanism will be described. Before the leading edge of the sheet 9 conveyed by the feed roller pair 4 reaches the shift roller pair 2, the shift roller pair is separated and the gate member 3 is raised to a protruding position that closes the sheet conveying path.

  The feed roller pair 4 conveys the sheet 9 in a pressure contact state, and presses the sheet 9 against the gate member 3 while reducing the conveyance speed immediately before the leading end of the sheet 9 abuts against the gate member 3 to over convey the sheet 9. As a result, an upwardly curved buffer B is formed on the sheet 9 between the gate 3 and the feed roller pair 4, and the inclination of the leading end of the sheet 9 along the gate 3 along the gate 3 by the elastic force ( After correcting the meandering, the shift roller pair 2 is closed and the paper 9 is held in pressure contact.

  Subsequently, the gate member 3 is lowered to the retracted position for opening the paper conveyance path, the feed roller pair 4 is separated, the paper 9 is conveyed by the shift roller pair 2 with the buffer B released, and the downstream paper conveyance path 13 is conveyed. When the sheet reaches the detection sensor 5 in the side, the position of the side edge in the direction perpendicular to the transport direction of the sheet 9 (the direction perpendicular to the paper surface, here referred to as “main scanning direction”) is detected by the detection sensor 5. Is detected, and the shift direction and shift amount of the sheet 9 from the reference position in the main scanning direction are detected.

Then, the shift roller pair 2 is moved (shifted) in the main scanning direction by the amount of deviation in the opposite direction to the detected deviation direction, thereby correcting the positional deviation of the paper 9 in the main scanning direction and correcting the posture of the paper. To complete.
Then, after the sheet 9 is nipped by a pair of conveyance rollers (not shown) in the sheet conveyance path 13 on the downstream side of the shift roller pair 2, the shift roller pair 2 is separated again, and the gate member 3 is moved again through the sheet conveyance path. The position is raised to the close position, and the feed roller pair 4 is brought into pressure contact again to prepare for the posture correction of the next sheet.

The position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4 in the series of sheet alignment operations are performed by the gate switching cam 17 and the shift roller separation cam provided on the common cam shaft 6. 18, a feed roller separation cam 19, a shift roller separation lever 20, and a feed roller separation lever 21.
The position switching operation of the gate member 3 and the separating / pressing operation of the shift roller pair 2 and the feed roller pair 4 are performed by the rotation of the common cam shaft 6, and the gate member 3 and the shift roller are operated by the sequence shown in FIG. The pair 2 and the feed roller pair 4 repeat the operation states (1) to (4) in FIG.

  In order to form a paper conveyance path in this paper alignment mechanism, the distance between the shift roller lower conveyance guide 12a and the shift roller upper conveyance guide 12b disposed from the downstream side to the upstream side of the shift roller pair 2 is , Expanding toward the upstream side. Further, the feed roller lower conveyance guide 14a arranged from the upstream side to the downstream side of the feed roller pair 4 extends to a position close to the upstream end of the shift roller lower conveyance guide 12a, and feed roller upper conveyance The downstream side of the guide 14b is short and bent upward.

  When the buffer B is formed on the sheet 9 between the gate member 3 and the feed roller pair 4 at the downstream end in the transport direction of the feed roller upper transport guide 14b, the height of the buffer is kept below a certain level. In order to suppress, the auxiliary guide 15 which is somewhat curved is fixed to a holder 26 provided on the upper feed guide 14b. Thereby, the gap of the conveyance path between the auxiliary guide 15 and the lower conveyance guide 14a of the feed roller part is made wider than the gap of the conveyance path in the feed roller part and the shift roller part, and the gate member 3 and the feed roller pair 4 The buffer B is easily formed on the paper 9 between the two.

  Further, the shift roller unit lower conveyance guide 12a and the shift roller unit upper conveyance guide 12b are independent of the conveyance guides of other parts, and the shift roller unit lower conveyance guide 12a and the shift roller unit lower upper conveyance guide 12b are aligned. The shift roller pair 2 and the shift roller pair 2 can be moved in a direction perpendicular to the sheet conveyance direction.

  In such a conventional printing apparatus, when a sheet having a low rigidity such as a thin sheet or a sheet with a curled tip is conveyed in the sheet aligning mechanism unit, a gap between the conveyance paths of the auxiliary guide unit is large. 4, in the process of transporting the sheet 9 toward the gate member 3, the leading end of the sheet is easily lifted by the momentum during transport, and the lifted leading end of the sheet is, as shown in FIG. 7, the entrance of the shift roller unit upper transport guide 12 b. There is a problem that a jam may occur due to being caught on the upper side or jumping out from the gap between the shift roller upper conveyance guide 12b and the auxiliary guide 15.

  The present invention has been made to solve such a problem. In the recording medium alignment mechanism of the printing apparatus, recording is performed during conveyance between the feed roller and the gate member regardless of the rigidity of the conveying medium. Prevents the occurrence of transport jams due to the rising of the leading edge of the medium, and ensures the followability of the leading edge of the recording medium to the gate member by forming a buffer of the recording medium between the gate member and the feed roller, and high recording medium running The purpose is to achieve both stability.

  The printing apparatus according to the present invention includes a recording medium storage unit that stores a recording medium, a printing unit that prints an image on the recording medium, and a recording that conveys the recording medium that is sent one by one from the recording medium storage unit to the printing unit. A recording medium alignment mechanism for correcting the posture of the recording medium to be conveyed upstream of the printing unit in the recording medium conveyance path in the recording medium conveyance direction. The mechanism portion arranges a shift roller pair and a feed roller pair each composed of a driving roller and a driven roller, which can be brought into contact with and separated from each other at a predetermined interval on the downstream side and the upstream side in the recording medium conveyance direction. A protruding position that is inserted into the recording medium conveyance path downstream of the shift roller pair in the recording medium conveyance direction to prevent the recording medium from passing, and retreats from the recording medium conveyance path to prevent the recording medium from passing. The printing apparatus and a displaceable gate member in a retracted position to ability to achieve the above object, is characterized by being configured in the following manner.

That is, the recording medium conveyance guide on the shift roller pair side forming the recording medium conveyance path in the recording medium alignment mechanism section and the recording medium conveyance guide on the feed roller pair side are provided separately, and the feed roller opposite side A part of the upper recording medium conveyance guide on the downstream side in the recording medium conveyance direction as an auxiliary guide that can be rotated to a position that widens and narrows a gap that forms a recording medium conveyance path with the lower recording medium conveyance guide With composition
A part of the upper recording medium conveyance guide on the shift roller opposite side on the upstream side in the recording medium conveyance direction is configured as a rotatable rotation guide part, and an end of the rotation guide part on the upstream side in the recording medium conveyance direction is formed. A position where the auxiliary guide is brought into contact with the lower surface of the free end portion on the downstream side in the recording medium conveyance direction, and the auxiliary guide is rotated by the rotation guide portion to narrow and widen the gap forming the recording medium conveyance path; It was comprised so that it might rotate.

  When the recording medium is conveyed toward the shift roller pair and the gate means by pressing the feed roller pair in a state where the gate member is displaced to the protruding position and the shift roller pair is separated, Then, the auxiliary guide is rotated by the rotating guide portion to a position that narrows the gap forming the recording medium conveyance path, the front end of the recording medium is abutted against the gate member, and then the recording is performed by the feed roller pair. When the buffer is formed on the recording medium between the gate member and the feed roller pair by over-conveying the medium, the rotation guide portion causes the auxiliary guide to widen the gap that forms the recording medium conveyance path. A means for rotating is provided.

  The means for rotating the auxiliary guide by the rotation guide portion is fixed to a cam shaft common to a cam for controlling the contact and separation operation of the feed roller pair and a cam for controlling the displacement operation of the gate member. A cam for controlling the contact / separation operation of the shift roller pair and the cam surface of the cam are always in contact with the cam. The feed roller pair is brought into contact with and separated from the cam and the rotation guide portion is rotated. It is preferable that the lever has a driving piece to be driven.

The means for rotating the auxiliary guide by the rotation guide unit is also a direction in which the rotation guide unit widens a gap that forms a recording medium conveyance path between the rotation guide unit and the lower recording medium conveyance guide on the shift roller opposite side. The auxiliary guide may be rotated to a position where a gap for forming a recording medium conveyance path is widened between the auxiliary guide and the lower recording medium conveyance guide on the opposite side of the feed roller.

Further, the means for rotating the auxiliary guide by the rotation guide portion can also rotate the upper auxiliary guide to a plurality of positions as a position to widen a gap forming the recording medium conveyance path.
The means for rotating the auxiliary guide by the rotation guide part has a cam surface of a cam for controlling the contact / separation operation of the shift roller pair in a plurality of stages. You may make it rotate a guide to several positions as a position which expands the clearance gap which forms the said recording-medium conveyance path.

In the printing apparatus according to the present invention, as described above, the recording medium alignment mechanism unit control method includes a portion of the upper recording medium conveyance guide on the opposite side of the feed roller on the downstream side in the recording medium conveyance direction between the lower recording medium conveyance guide. As an auxiliary guide that can be turned to a position that widens and narrows the gap that forms the recording medium conveyance path, the upper recording medium conveyance guide on the opposite side of the shift roller rotates a part on the upstream side in the recording medium conveyance direction. In the printing apparatus, which is configured as a possible rotation guide portion, and an end portion on the upstream side in the recording medium conveyance direction of the rotation guide portion is brought into contact with the lower surface of the free end portion on the downstream side in the recording medium conveyance direction of the auxiliary guide. A recording medium alignment mechanism control method,
The rotation guide part is rotated in the separated state of the shift roller pair,
When the recording medium is conveyed toward the shift roller pair and the gate means by pressing the feed roller pair in a state where the gate member is displaced to the blocking position and the shift roller pair is separated, The auxiliary guide is rotated by the rotating guide portion to a position that narrows the gap forming the recording medium conveyance path, the front end of the recording medium is abutted against the gate member, and then the recording medium is moved by the feed roller pair. When the buffer is formed on the recording medium between the gate member and the feed roller pair by over-conveying, the rotation guide portion rotates the auxiliary guide to a position where the gap forming the recording medium conveyance path is widened. It is made to move.

  Three cams fixed to a common camshaft respectively make contact / separation operation of the shift roller pair, displacement operation of the gate member, contact / separation operation of the feed roller pair, and rotation of the rotation guide portion. It is preferable to control the rotation of the auxiliary guide by movement in conjunction with each other.

  According to the present invention, in the recording medium alignment mechanism portion of the printing apparatus, the upstream portion of the auxiliary conveyance guide and the upper conveyance guide of the shift roller portion can be rotated in the recording medium conveyance direction, and in a series of posture correction operations of the recording medium. Regardless of the rigidity of the recording medium, the recording medium is aligned by increasing or decreasing the clearance of the auxiliary guide conveyance path in conjunction with the position switching operation of the gate member and the separation / pressing operation of the shift roller pair and the feed roller pair. The lift of the recording medium front end in the auxiliary guide section conveyance path of the mechanism section is suppressed, and jamming due to catching of the shift roller section at the recording medium front end to the conveyance guide entrance or jumping out of the gap is prevented, and as a result, the gate member The follow-up to the gate member at the leading edge of the recording medium is ensured by forming a buffer on the recording medium between the feed roller pair and the feed roller pair. Realization of high recording medium running stability in the recording medium aligning mechanism becomes possible.

FIG. 2 is a diagram illustrating a schematic configuration of a recording medium conveyance path in an embodiment of the printing apparatus according to the present invention. FIG. 2 is a mechanism diagram illustrating a configuration example of a recording medium alignment mechanism unit in FIG. 1. It is a mechanism figure which similarly shows the different operation | movement state. FIG. 3 is a sequence diagram illustrating the operation of each unit accompanying the rotation of the camshaft in the recording medium alignment mechanism unit illustrated in FIGS. 1 and 2. FIG. 2 is a schematic drawing showing the printing apparatus main body 100 shown in FIG. 1 in a simplified manner. It is a mechanism figure which shows the structure of the recording medium alignment mechanism part in the conventional printing apparatus. It is a figure for demonstrating the problem similarly. FIG. 6 is a sequence diagram illustrating changes in the operating state of the gate member, the shift roller pair, and the feed roller pair in a series of recording medium alignment operations by the recording medium alignment mechanism unit illustrated in FIG. 5.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
[Recording medium conveyance path in printing apparatus]
FIG. 1 is a diagram showing a schematic configuration of a recording medium conveyance path in an embodiment of a printing apparatus according to the present invention. The printing apparatus includes a printing apparatus main body 100 and a mass feeding apparatus 200. In the printing apparatus main body 100, a paper tray 10 (actually provided in a plurality of stages, but shown in a simplified manner) that is a recording medium storage unit that stores paper as a recording medium, and one sheet is fed from the tray. And a sheet conveyance path 7 which is a recording medium conveyance path for conveying a sheet to be printed to a printing unit (image forming unit) (not shown). The printing unit prints images such as characters and graphics on the conveyed paper. Hereinafter, in the description of this embodiment, the recording medium is described as “paper”, but the recording medium includes various types of printable films and sheets.

  Each of the paper conveyance paths 7 is formed by a guide plate or the like, and a paper feeding path 7a for feeding the paper 9 as a recording medium from the paper tray 10 and a double-sided conveyance for reversing the paper printed on one side. The sheet conveyance path 7b, the curve-shaped conveyance path 7c, and the straight-shaped conveyance path 7d for carrying in the sheet from the outside are provided, and the sheet conveyance path by the sheet alignment mechanism unit 1 according to the present invention is provided on the downstream side. The curve-shaped conveyance path 7 c and the straight-shaped conveyance path 7 d merge at point A on the upstream side of the feed roller pair 4 of the sheet alignment mechanism unit 1.

  A pair of pickup roller 71 and paper feed roller 72 and separation roller 73 is provided near the entrance of the paper feed path 7a, and a pair of transport rollers 74 is provided near the exit. The curved conveyance path 7c is provided with conveyance roller pairs 75 and 76, and the straight conveyance path 7d is provided with a conveyance roller pair 77. The conveyance roller pairs 76 and 77 are each composed of a drive roller and a driven roller. Can be pressed against and separated from the drive roller, and is urged by springs 78 and 79 in the direction of pressure contact.

  On the other hand, in the large-volume paper feeder 200, a large-volume paper tray 11 (actually a plurality of large-sized paper trays are provided in a simplified manner), which is a recording medium storage unit, and the large-volume paper tray 11 A sheet feeding path 8 for feeding the sheet 9 as a recording medium fed one by one to the straight-shaped conveyance path 7d of the printing apparatus main body 100 is provided. A pair of a pickup roller 81, a paper feed roller 82, and a separation roller 83 is provided near the entrance of the paper feed path 8, a pair of transport rollers 84 is provided on the downstream side, and a pair of transport rollers 85 is provided near the exit. Yes. The conveying roller pair 85 includes a driving roller and a driven roller. The driven roller can be pressed against and separated from the driving roller and is urged by a spring 86 in a pressing direction.

The sheet alignment mechanism 1 will be described in detail with reference to FIGS. 2 and 3. In FIG. 1, a shift roller pair 2, a gate member 3, a feed roller pair 4, a detection sensor 5 similar to the conventional example shown in FIG. Only the shift roller unit conveyance guide 12, the feed roller unit conveyance guide 14, the auxiliary guide 15 and the like are shown in a simplified manner.
The distance between each pair of adjacent transport rollers and between the feed roller pair 4 and the shift roller pair 2 is a distance that can transport even a minimum size sheet, for example, about 150 mm to 180 mm.

  The uppermost sheet 9 is fed from the sheet tray 10 in the printing apparatus main body 100 to the sheet feeding path 7a by the pickup roller 71, separated into one sheet by the sheet feeding roller 72 and the separation roller 73, and conveyed. It is sent to the curve-shaped conveyance path 7c by the roller pair 74. Alternatively, a sheet printed on one side by a printing unit (not shown) is reversed and sent from the duplex conveyance path 7b to the curved conveyance path 7c. Any one of these sheets is conveyed in the curve-shaped conveyance path 7c by the conveyance roller pairs 75 and 76, and is sent to the sheet alignment mechanism unit 1 through the point A.

Further, the uppermost sheet 9 is sent out from the large-volume sheet tray 11 of the large-volume sheet feeding device 200 to the sheet feeding path 8 by the pickup roller, and is separated and fed into one sheet by the sheet feeding roller 82 and the separation roller 83. A pair of conveyance rollers 84 and 85 are fed into the straight conveyance path 7d of the printing apparatus main body 100. The sheet can be transported by the transport roller pair 77 of the straight-shaped transport path 7d and sent to the sheet aligning mechanism unit 1 through the point A.
These are selected according to the designated paper, print mode, and the like.

  The basic configuration of the sheet alignment mechanism unit 1 and the sheet posture correction operation are substantially the same as those of the conventional example described above, but the upstream guide part of the upper guide of the auxiliary guide 15 and the shift roller unit guide 12 in the sheet transport direction. Are supported so that each free end thereof is engaged, and during a series of paper alignment operations, they are rotationally displaced, and the paper 9 is moved between the feed roller pair 4 and the shift roller pair 2. The difference is that the gap in the conveyance path of the auxiliary guide part that forms the buffer B curved in (3) is widened or narrowed.

[Paper alignment mechanism]
2 and 3 are mechanism diagrams showing an example of the configuration of the sheet aligning mechanism unit 1, and portions corresponding to those in FIGS. 6 and 7 are denoted by the same reference numerals.
The configuration of the sheet alignment mechanism unit 1 other than the portions related to the shift roller unit conveyance guide 12 and the auxiliary guide 15 is the same as the configuration described with reference to FIGS. This will be described in detail.

The shift roller pair 2 and the feed roller pair 4 are each composed of a lower drive roller and an upper driven roller, and each axis thereof is fixed in parallel to a side plate (not shown) on the front side and the back side in the drawing. However, the driven roller is supported by the drive roller so as to be capable of being pressed and separated, and is urged by springs 31 and 32 in the direction of pressing the drive roller.
An opening is formed in the shift roller section conveyance guide 12 so that the shift roller pair 2 can be pressed and separated in the sheet conveyance path of the gap, and the gate member 3 has a comb-like gate at the tip. A plurality of slots into which the pieces 3a are inserted are also formed.

  The shift roller unit conveyance guide 12 includes a shift roller unit lower conveyance guide 12a, a fixed guide unit 12b and a rotation guide unit 12c into which the shift roller unit upper conveyance guide is divided. That is, the shift roller unit upper conveyance guide is composed of a fixed guide portion 12b on the downstream side in the paper conveyance direction and a rotation guide portion 12c on the upstream side, and is fastened by a shaft member or the like at the rotation fulcrum 23.

  The fixed guide portion 12b on the downstream side is fixed to a side plate (partially indicated by a broken line) 22, but a support pin 25 is provided at a side end of the upstream rotation guide portion 12c. Is inserted into a long hole 24 provided in the side plate 22. The long hole 24 is formed in an arc shape centered on the rotation fulcrum 23. Therefore, the rotation guide portion 12 c can rotate in the direction indicated by the arrow D within the range of the long hole 24 around the rotation fulcrum 23.

The feed roller unit conveyance guide 14 is configured by a feed roller unit lower conveyance guide 14a and a feed roller unit upper conveyance guide 14b, and an opening is formed so that the feed roller pair 4 can be pressed and separated in the paper conveyance path of the gap. Has been.
A pair of holders 16 are fixed to both ends in the width direction with respect to the sheet conveyance path of the support piece 14c where the downstream end of the feed roller upper conveyance guide 14b is bent upward, and the pair of holders A shaft hole is formed in each 16.

On the other hand, the auxiliary guide 15 covers substantially the entire area on the paper transport path between the downstream end of the feed roller upper transport guide 14b and the upstream end of the shift roller upper transport guide 12b, and extends in the paper transport direction. It is made of resin in a shape that is curved upward and somewhat convex. Pins 15 a protrude from both side surfaces of the auxiliary guide 15 on the upstream side in the sheet conveying direction, and the pins 15 a are loosely fitted into the shaft holes of the pair of holders 16, respectively.
Therefore, the auxiliary guide 15 is supported by the holder 16 so as to be rotatable in the direction of arrow E with the pin 15a as a fulcrum. This auxiliary guide 15 constitutes the downstream portion of the feed roller upper transport guide 14b.

Further, the upstream end portion of the rotation guide portion 12c of the shift roller portion conveyance guide 12 is in contact with the lower surface of the free end portion of the auxiliary guide 15 on the downstream side in the sheet conveyance direction. The contact state is always maintained by the weight of the guide 15.
Therefore, the auxiliary guide 15 can be rotated to a position for narrowing and widening a gap for forming a paper conveyance path between the auxiliary guide 15 and the lower paper conveyance guide 14a by the rotation of the rotation guide portion 12c. Note that the auxiliary guide 15 may be biased by a spring so as to always provide left-hand turning ability in FIG.

  The shift roller separation lever 20 has an upper end portion rotatably supported on the side plate 22 by a shaft 41, and a driving piece 20a extending below the shaft 2a of the driven roller of the shift roller pair 2 is fixed to the upper end portion. is doing. As shown in FIG. 2, when the large diameter portion of the cam surface 18 a of the shift roller separation cam 18 is in contact with the shift roller separation lever 20, the shift roller separation lever 20 turns right about the shaft 41. The driving piece 20a pushes up the shaft 2a against the urging force of the spring 31, and the driven roller of the shift roller pair 2 is separated from the driving roller so that the sheet is not conveyed.

At this time, the drive piece 20a of the shift roller separation lever 20 pushes down the lever piece 26 that is bent to the left from the rotation fulcrum portion of the rotation guide portion 12c of the shift roller portion conveyance guide 12 and rotates. As shown in FIG. 2, the moving guide portion 12c is turned to the left and the auxiliary guide 15 is turned to the right against its own weight, thereby forming a paper conveyance path between the feed roller portion and the lower paper conveyance guide 14a. Set the position to widen the gap.
In this embodiment, the large-diameter portion of the cam surface 18a of the shift roller separation cam 18 is formed in a plurality of stages having different distances from the cam shaft 6, so that the rotation guide portion by the rotation of the shift roller separation lever 20 is formed. The rotation amount of 12c is varied, and the auxiliary guide 15 is rotated according to the rotation amount of the rotation guide portion 12c, so that the positions for widening the gaps forming the paper conveyance path can be set to a plurality of different positions.

When the shift roller separation cam 18 rotates in the direction indicated by the arrow C and the large diameter portion of the cam surface 18a does not come into contact with the shift roller separation lever 20, the shaft 2a and the drive piece are driven by the biasing force of the spring 31. 20a is pushed down, the shift roller separation lever 20 rotates counterclockwise, and the driven roller of the shift roller pair 2 comes into pressure contact with the drive roller as shown in FIG.
At this time, since the drive piece 20a of the shift roller separation lever 20 releases the lever piece 26 of the rotation guide portion 12c, the auxiliary guide 15 descends counterclockwise while rotating the rotation guide portion 12c clockwise by its own weight. It becomes a position to narrow the gap forming the transport path

  An intermediate portion of the feed roller separation lever 21 is rotatably supported by a side plate by a shaft 42, and a tip portion thereof is bent and extends below the shaft 4 a of the driven roller of the feed roller pair 4. As shown in FIG. 2, when the large diameter portion of the cam surface of the feed roller separation cam 19 is not in contact with the feed roller separation lever 21, the feed roller separation lever 21 is fed by a biasing means (not shown). It is turned right so as to follow the roller separation cam 19, and its tip is separated from the shaft 4a. Therefore, the shaft 4a is pushed down by the urging force of the spring 32, and the driven roller of the feed roller pair 4 is in pressure contact with the driving roller, so that the sheet can be conveyed.

  From this state, when the feed roller separation cam 19 rotates in the direction of arrow C and the large diameter portion of the cam surface comes into contact with the feed roller separation lever 21 as shown in FIG. Rotates counterclockwise about the shaft 42, and the tip of the shaft 4a pushes up the shaft 4a against the urging force of the spring 32, and the driven roller of the feed roller pair 4 is separated from the driving roller so that the paper is not conveyed. To do.

  The gate member 3 is provided with a lever portion 3b that is bent substantially perpendicularly from a gate piece 3a having a comb-like tip at its tip, and is bent upward from a side end of an intermediate portion thereof. The support piece 3c is rotatably supported on the side plate 22 by a shaft 43. The end of the lever portion 3b opposite to the gate piece 3a extends to a position where it can come into contact with the gate switching cam 17. As shown in FIG. 2, when the large diameter portion of the cam surface of the gate switching cam 17 is not in contact with the lever portion 3b, the lever portion 3b is rotated clockwise by the urging force of the spring 33, and the gate piece 3a is in a protruding position that protrudes into the paper conveyance path in the shift roller unit conveyance guide 12, and is in a state in which the leading edge of the conveyed paper can be locked.

  From this state, when the gate switching cam 17 rotates in the direction of arrow C and the large diameter portion of the cam surface comes into contact with the lever portion 3b of the gate member 3 as shown in FIG. The gate piece 3a is turned to the left against the urging force of the spring 33, so that the gate piece 3a is retracted from the sheet conveyance path in the shift roller section conveyance guide 12, and the sheet can pass therethrough.

On the upstream side of the feed roller pair 4 in the paper conveyance direction, a photosensor 28 for detecting double feed comprising a light emitting portion and a light receiving portion facing each other across the paper conveyance path by the feed roller portion conveyance guide 14 is disposed. Of course, the feed roller section conveyance guide 14 is formed so as not to obstruct the optical path of the photosensor 28.
In this embodiment, the gate switching cam 17, the shift roller separation cam 18, the feed roller separation cam 19, and the feed roller separation lever 21 are made of resin, the shift roller separation lever 20 is made of aluminum die casting, and the gate member 3 is made of sheet metal. It is built.

  The order of the paper transport position correction and the meandering (tilt) correction operation in the paper alignment mechanism unit 1 is the same as that described in the background art. That is, as shown in FIG. 2, the shift roller pair 2 is separated before the leading edge of the sheet 9 reaches the shift roller pair 2, and the gate member 3 has the gate piece 3 a inserted into the shift roller section conveyance guide 12. Then, the sheet conveyance path is raised to the protruding position. The pair of feed rollers 4 conveys the sheet in a pressure contact state, and presses the sheet 9 against the gate member 3 while decelerating the conveyance speed immediately before the leading end of the sheet 9 abuts against the gate member 3 to overconvey.

  As a result, a buffer B in which the sheet 9 is curved upward is formed between the gate member 3 and the feed roller pair 4 as shown by a one-dot chain line in FIG. 2, and the leading end of the sheet 9 extends along the gate member 3. After correcting the meandering (inclination), the shift roller pair 2 holds the sheet in pressure contact.

  Subsequently, the gate member 3 is lowered and retracted from the conveyance path in the shift roller unit conveyance guide 12, and the sheet 9 is conveyed by the shift roller pair 2 while the feed roller pair 4 is separated and the buffer B is released. When the paper 9 reaches the detection sensor 5, the detection sensor 5 detects the position of the end portion (side end portion) of the paper 9 in the main scanning direction, and the reference in the main scanning direction of the paper 9 from the detected information. The shift direction and shift amount with respect to the position are calculated. The shift roller pair 2 is moved in the direction (main scanning direction) perpendicular to the sheet conveying direction together with the shift roller unit conveying guide 12 by the amount of deviation in the direction opposite to the calculated deviation direction, so Correct the position.

  After that, after the position-corrected sheet 9 is nipped by a roller pair (not shown) on the downstream side of the shift roller pair 2, the shift roller pair 2 is separated again to bring the gate member 3 to the position for closing the sheet conveyance path again. The feed roller pair 4 is brought into pressure contact again to prepare for the next sheet.

As the detection sensor 5 for detecting the deviation in the main scanning direction of the paper, as described in Patent Document 1, various sensors such as a CIS sensor, a CCD linear image sensor, and a plurality of photocouplers, which are contact image sensors, are used. However, if the CIS sensor is used, it is possible to easily detect the deviation direction and the deviation amount of the paper with an accuracy corresponding to the resolution.
Although the feed roller pair 4 is moved in the main scanning direction by the pressing force of the cam and the spring, the mechanism is the same as in the prior art, and the description thereof is omitted.

  In the sheet alignment mechanism control method according to the present invention, the gate member 3 is raised to the protruding position that closes the sheet conveyance path and the feed roller pair 4 is pressed against the movement of the position of the auxiliary guide 15 when performing the sheet alignment operation. At the timing when the sheet 9 is transported toward the member 3, the auxiliary guide 15 is moved in a direction to narrow the gap of the auxiliary guide portion transport path. Subsequently, at the timing at which the leading edge of the sheet 9 is pressed against the gate member 3 to carry it over and the buffer B is formed on the sheet 9 between the gate member 3 and the feed roller pair 4, as shown in FIG. The auxiliary guide 15 is moved in a direction to widen the gap in the conveyance path.

  As a result, the lifting of the sheet in the auxiliary guide section conveyance path is suppressed, and the leading edge of the sheet is caught by the entrance end of the shift roller section upper conveyance guide 12b and the gap between the shift roller section upper conveyance guide 12b and the auxiliary guide 15 is prevented. To prevent jamming due to popping out of the paper and to form an appropriate buffer on the paper between the gate member 3 and the feed roller 4 to correct the posture and realize paper running stability. It becomes possible to make it.

  The three cams of the gate switching cam 17, the shift roller separation cam 18, and the feed roller separation cam 19 are provided on the common cam shaft 6, and the auxiliary guide 15 is rotated by the rotation of the cam shaft 6 in the direction of arrow C. The main part of the means for performing the position switching in conjunction with the position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4 is constituted. The cam shaft 6 is rotated by a motor whose drive is controlled by a control unit (not shown).

FIG. 4 shows a sequence of the position switching operation of the gate member 3, the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4, and the position switching operation of the auxiliary guide 15. The horizontal axis is the rotation phase (angle) of the cam shaft 6 that rotates integrally with the auxiliary guide drive cam 23, and shows a sequence of one rotation (360 ° rotation).
In FIG. 4, at the home position (HP) where the rotation angle of the cam shaft 6 is 0 °, the gate member 3 is in the retracted position, the shift roller pair 2 is in a separated state, and the feed roller pair 4 is in a pressure contact state. The auxiliary guide is in the reference position.

The state shown in FIG. 2 is a state in which the rotation angle of the cam shaft 6 in FIG. 4 is in the vicinity of α °, and the state shown in FIG. 3 is a state in which the rotation angle of the cam shaft 6 is in the vicinity of β °.
4, the auxiliary guide 15 moves in two steps from the standard position to positions 1 and 2 above the standard position (positions that make the paper conveyance path gap wider than the standard interval) in the angle range indicated by U. it can.

In this embodiment, the large-diameter portion of the cam surface 18 of the feed roller separating cam 19 is formed in three stages having different distances from the cam shaft 6 to assist the feed roller pair 2 in a separated state. The guide 15 can be rotated to a standard position (a position for narrowing the gap in the auxiliary guide part conveyance path) and an upper position 1 and 2 (a position for widening the gap in the auxiliary guide part conveyance path).
Note that it is possible to change the shape of the large diameter portion of the cam surface of the auxiliary guide drive cam 23 to three or more upper positions.

  Regarding the position switching of the auxiliary guide 15 when the buffer B is formed between the gate member 3 and the feed roller pair 4, there is a difference in the buffer formation height even when the buffer amount is the same between the low-rigidity paper and the high-quality paper (stiffness). Therefore, the rotation of the auxiliary guide drive cam 23 is such that the clearance of the auxiliary guide portion conveyance path is wider when the high-stiffness paper buffer is formed than when the low-rigidity paper buffer is formed. It is possible to switch the height position of the auxiliary guide 15 by changing the phase.

In this case, as in the above-described embodiment, when the auxiliary guide 15 has a plurality of positions as positions for widening the gap of the sheet conveyance path formed between the auxiliary sheet 15 and the lower sheet conveyance guide 14a, the recording used for printing is performed. According to the rigidity of the medium, the auxiliary guide 15 may select a plurality of positions that widen the gaps forming the paper conveyance path.
The plurality of positions can be set according to the shape of the cam surface of the shift roller separation cam 18 that rotates the shift roller separation lever 20 as described above.

  Regarding the paper stiffness determination method, for example, a paper stiffness rank table is created in advance using a matrix of various paper types and paper thicknesses and stored in the memory of the control unit. Based on the conditions of the paper type and the paper thickness to be determined, the CPU of the control unit can make a determination with reference to the table.

Alternatively, the light transmittance from the light emitting portion to the light receiving portion is detected by using a photo sensor 28 for detecting double feed provided on the upstream side of the feed roller pair 4, and the paper type and paper thickness are determined based on the detection result. It is conceivable to recognize and determine the paper rigidity rank. The photo sensor 28 or another photo sensor may be provided near the exit of the paper tray 10 to recognize the paper type and paper thickness immediately after the start of paper feeding.
The thickness of the sheet is generally expressed in g / ^{m 2,} with 220 g / ^{m 2} or more Heavyweight, generally higher stiffness, at 100 g / ^{m 2} or less light soy, generally less rigid.

  As described above, the gap in the conveyance path of the auxiliary guide unit in the sheet alignment mechanism unit 1 is used for the position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller 2 pair and the feed roller pair 4 in a series of sheet alignment operations. By increasing and decreasing in conjunction with each other, the feed roller pair 4 feeds the sheet to the gate member while ensuring followability of the leading end of the sheet to the gate member 3 by forming the sheet buffer between the gate member 3 and the feed roller pair 4. Therefore, it is possible to suppress the occurrence of jamming due to the sheet tip portion floating in the auxiliary guide portion conveyance path when conveying toward the sheet 3.

  In the above-described embodiment, the shift roller separation cam 18 and the shift roller separation lever for controlling the separation / contact of the shift roller pair are used for the position control of the auxiliary guide 15, so a new dedicated cam or lever is added. There is also an advantage that it can be implemented at low cost.

  [Overall configuration of printing device]

Here, the overall configuration of an embodiment of the printing apparatus according to the present invention will be briefly described.
FIG. 5 is a schematic diagram showing the printing apparatus (image forming apparatus) main body 100 shown in FIG. 1 in a simplified manner, and parts corresponding to those in FIG. Although the paper feed roller 72, the separation roller 73, the transport roller 78, and the like in FIG. 1 are not shown, they actually exist.

  The printing apparatus main body 100 includes a tandem intermediate transfer type color printing unit, and the portion surrounded by a broken line is the above-described sheet alignment mechanism unit 1. In this printing apparatus main body 100, color printing (color image formation) is performed on a sheet that is a recording medium that is conveyed through the above-described sheet conveying path, and whose posture is corrected by the sheet aligning mechanism unit 1 and sent out. Various members constituting the printing section are provided.

  In the upper part, photosensitive drums 101Y, 101C, 100M, and 100K as image carriers constituting a color image forming unit, charging rollers 110Y, 110C, 110M, and 110K and optical writing around each photosensitive drum. An irradiation unit for image writing laser light of each color by the device 102 and developing devices 103Y, 103C, 103M, and 103K are provided. Y, C, M, and K represent yellow, cyan, magenta, and black, respectively, corresponding to the development color of each image that is attached to each code.

  Further, an intermediate transfer belt, which is an intermediate transfer member, is formed by a pair of drive rollers 111, a driven roller 112, and a lower secondary transfer counter roller 113 so as to be in contact with the respective lower end surfaces of the photosensitive drums 101Y, 101C, 100M, and 100K. 104 is stretched and appropriate tension is applied by the tension roller 114.

  A secondary transfer roller 115 is disposed at a position facing the secondary transfer counter roller 113 and the intermediate transfer belt 104, and a secondary transfer portion is formed by a nip portion between the secondary transfer roller 115 and the intermediate transfer belt 104. Is configured. The secondary transfer unit corresponds to the path of the sheet conveyed from the sheet alignment mechanism unit 1.

  A sheet conveying belt 106 is provided on the downstream side of the secondary transfer unit, and a fixing device 107 is further provided on the downstream side thereof. A discharge tray 120 is mounted on the side surface of the printing apparatus main body 100 on which printed sheets are discharged. However, instead of the paper discharge tray 120, a sorter or a post-processing device for aligning and stacking printed sheets one by one or stapling may be connected. Needless to say, the mass feeding device 200 shown in FIG. 1 can be connected to the right side surface in FIG.

  In the printing apparatus main body 100, the surface of each of the photosensitive drums 101Y, 101C, 100M, and 100K is uniformly charged by the charging rollers 110Y, 110C, 110M, and 110K, and then the image writing laser light of each color by the optical writing apparatus 102 is obtained. 5, the photosensitive drums 101Y, 101C, 100M, and 100K are sub-scanned by rotating counterclockwise in FIG. 5 while being scanned in the main scanning direction (perpendicular to the paper surface). An image is formed.

  The electrostatic latent images on the respective photosensitive drums 101Y, 101C, 100M, and 100K are developed by the developers of the respective colors of the developing devices 103Y, 103C, 103M, and 103K, and toner images of yellow, cyan, magenta, and black are used. Is formed. The toner on each of the photosensitive drums 101Y, 101C, 100M, and 100K is applied by applying a voltage to a primary transfer roller (not shown) that faces each of the photosensitive drums 101Y, 101C, 100M, and 100K with the intermediate transfer belt 104 interposed therebetween. The images are sequentially transferred onto the intermediate transfer belt 104 that rotates in the direction indicated by the arrow, thereby forming a full-color toner image.

  In accordance with the timing when the full-color toner image on the intermediate transfer belt 104 in the printing unit reaches the secondary transfer unit 105, the sheet that has passed through the sheet alignment mechanism unit 1 is conveyed to the secondary transfer unit, and the secondary transfer roller By applying a voltage to 115, the full-color toner image on the intermediate transfer belt 104 is transferred onto the paper. The sheet is conveyed to the fixing device 107 by the sheet conveying belt 106, where heat and pressure are applied to fix the toner image on the sheet. The paper on which printing has been completed in this manner is conveyed by a paper discharge roller (not shown) and discharged onto a paper discharge tray 120 outside the apparatus.

  When printing on both sides of a sheet, the fixing device 107 switches the conveyance path of the sheet on which the toner image is fixed on one side, and reverses the front and back to the duplex conveyance path 7b shown in FIG. From there, the paper is fed again by the printing unit through the curved conveyance path 7c and the sheet aligning mechanism unit 1 to form an image on the other side.

In this embodiment, an example in which the printing unit is a tandem type intermediate transfer type color printing unit has been described. However, the present invention is not limited to this, and a tandem type direct transfer type color printing unit may be a color printing unit other than the tandem type. Alternatively, a printing unit that forms a monochrome image may be used. Furthermore, the present invention is not limited to an electrophotographic printing apparatus, and can also be applied to an inkjet printing apparatus.
The present invention is not limited to the above-described embodiments and modifications thereof, and it is needless to say that various modifications can be made except for the requirements defined in the claims.

  The present invention can be applied to various printing apparatuses using an image forming apparatus such as a laser printer or an ink jet printer, and is particularly suitable for a commercial printing apparatus provided with a recording medium alignment mechanism in the recording medium conveyance path.

1: Paper alignment mechanism unit 2: Shift roller pair 3: Gate member 4: Feed roller pair 5: Detection sensor 6: Common cam shaft 7: Paper transport path 7a: Paper feed path 7b: Double-side transport path 7c: Curve Shape conveying path 7d: Straight shape conveying path 8: Paper feeding path 9: Paper (recording medium) 10: Paper tray 11: Mass paper tray 12: Shift roller section conveyance guide 12a: Shift roller section lower conveyance guide 12b: Shift roller Fixed guide portion 12c of the upper side conveyance guide: Rotation guide portion 13 of the shift roller portion upper conveyance guide 13: Paper conveyance path 14 on the downstream side of the shift roller pair 14: Feed roller portion conveyance guide 14a: Feed roller portion lower conveyance guide 14b: Feed roller upper conveyance guide 15: Auxiliary guide 15a: Pin 16, 26: Holder 17: Gate switching cam 18: Thread Trawler separation cam 18a: Cam surface 19: Feed roller separation cam 20: Shift roller separation lever 21: Feed roller separation lever 22: Side plate 23: Rotation fulcrum 24 of the rotation guide portion 24: Long hole 25: Support pin 26: Lever piece 28 : Photosensors 31-34: Spring 41-43: Shaft
71, 81: Pickup rollers 72, 82: Paper feed rollers 73, 83: Separation rollers 74 to 77, 84, 85: Pairs of conveying rollers 78.79, 86: Spring 100: Printer main body 200: Mass feed device 101Y, 101C, 100M, 100K: Photosensitive drum 102: Optical writing device 103Y, 103C, 103M, 103K: Developing device 104: Intermediate transfer belt 105: Secondary transfer unit 106: Paper transport belt 107: Fixing device 110Y, 110C, 110M, 110K: Charging roller 113: Secondary transfer counter roller 115: Secondary transfer roller 120: Paper discharge tray

JP 2008-50069 A

  The present invention relates to a printing apparatus using an image forming apparatus such as a laser printer, and more particularly to a recording medium alignment mechanism provided in a recording medium conveyance path and a control method thereof.

  2. Description of the Related Art In a printing apparatus using an image forming apparatus such as a commercial laser printer, a recording medium such as a transfer sheet stacked on a paper feeding apparatus is conveyed one by one along its conveyance path, and a photosensitive drum or a photosensitive drum is conveyed. The toner image formed on the photosensitive member such as a body belt is directly or once transferred to the intermediate transfer member, and then the paper is transferred to the transfer position to transfer the toner image, and the toner image is passed through the fixing device. Is fixed on the paper, and the image is printed on the paper.

  In such a printing apparatus, a paper alignment mechanism is provided in the paper conveyance path to the image transfer position of the printing unit, and corrects the posture of the recording medium and then conveys it to the transfer position, so that the correct position on the recording medium is obtained. The toner image is transferred to the surface.

  For example, as described in Patent Document 1, the sheet aligning mechanism unit of such a printing apparatus is positioned upstream in a state where the leading end of the sheet is abutted against a stopper (gate member) and the leading end is stopped. The paper is fed by the carrying means to form a curved buffer on the paper, and the inclination with respect to the carrying direction is corrected. Thereafter, the stopper is opened, the paper is nipped and conveyed by a pair of rollers positioned downstream of the stopper, and a direction perpendicular to the paper conveyance direction (by a detection means provided on the side near the downstream side of the stopper ( The width direction is detected from the reference position and the amount of deviation is detected, and the pair of rollers nipping the paper is moved by the detected amount of deviation in the opposite direction to the detected deviation direction. After correction, the paper is conveyed to the transfer position of the printing unit.

An example of a sheet alignment mechanism unit that is a recording medium alignment mechanism unit in such a conventional printing apparatus will be described with reference to FIGS. 6 includes a shift roller pair 2, a gate member (stopper) 3, a feed roller pair 4, a detection sensor 5, and the like, and is provided between the feed roller pair 4 and the shift roller pair 2. The distance (interval in the paper conveyance direction) and the conveyance path shape are substantially straight at a distance that allows conveyance of small-size paper.

The gate member 3 is urged by a spring so that the leading end projects into the downstream sheet conveyance path immediately after the shift roller pair 2 , and rotates between a protruding position for closing the sheet conveyance path and a retracted position for opening the sheet conveyance path. It is supported movably.
A sheet posture correction (alignment) operation in the sheet alignment mechanism will be described. Before the leading edge of the sheet 9 conveyed by the feed roller pair 4 reaches the shift roller pair 2 , the shift roller pair 2 is separated and the gate member 3 is raised to a protruding position that closes the sheet conveying path.

The feed roller pair 4 conveys the sheet 9 in a pressure contact state, and presses the sheet 9 against the gate member 3 while reducing the conveyance speed immediately before the leading end of the sheet 9 abuts against the gate member 3 to over convey the sheet 9. Thereby, a buffer B that is curved upward is formed on the sheet 9 between the gate member 3 and the feed roller pair 4, and the leading end of the sheet 9 is moved along the gate member 3 by the elastic force with respect to the conveyance direction of the sheet 9. After correcting the inclination (meandering), the shift roller pair 2 is closed to hold the sheet 9 in pressure contact.

  Subsequently, the gate member 3 is lowered to the retracted position for opening the paper conveyance path, the feed roller pair 4 is separated, the paper 9 is conveyed by the shift roller pair 2 with the buffer B released, and the downstream paper conveyance path 13 is conveyed. When the sheet reaches the detection sensor 5 in the side, the position of the side edge in the direction perpendicular to the transport direction of the sheet 9 (the direction perpendicular to the paper surface, here referred to as “main scanning direction”) is detected by the detection sensor 5. Is detected, and the shift direction and shift amount of the sheet 9 from the reference position in the main scanning direction are detected.

Then, the shift roller pair 2 is moved (shifted) in the main scanning direction by the amount of deviation in the opposite direction to the detected deviation direction, thereby correcting the positional deviation of the paper 9 in the main scanning direction and correcting the posture of the paper. To complete.
Then, after the sheet 9 is nipped by a pair of conveyance rollers (not shown) in the sheet conveyance path 13 on the downstream side of the shift roller pair 2, the shift roller pair 2 is separated again, and the gate member 3 is moved again through the sheet conveyance path. The position is raised to the close position, and the feed roller pair 4 is brought into pressure contact again to prepare for the posture correction of the next sheet.

The position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4 in the series of sheet alignment operations are performed by the gate switching cam 17 and the shift roller separation cam provided on the common cam shaft 6. 18, a feed roller separation cam 19, a shift roller separation lever 20, and a feed roller separation lever 21.
The position switching operation of the gate member 3 and the separating / pressing operation of the shift roller pair 2 and the feed roller pair 4 are performed by the rotation of the common cam shaft 6, and the gate member 3 and the shift roller are operated by the sequence shown in FIG. The pair 2 and the feed roller pair 4 repeat the operation states (1) to (4) in FIG.

  In order to form a paper conveyance path in this paper alignment mechanism, the distance between the shift roller lower conveyance guide 12a and the shift roller upper conveyance guide 12b disposed from the downstream side to the upstream side of the shift roller pair 2 is , Expanding toward the upstream side. Further, the feed roller lower conveyance guide 14a arranged from the upstream side to the downstream side of the feed roller pair 4 extends to a position close to the upstream end of the shift roller lower conveyance guide 12a, and feed roller upper conveyance The downstream side of the guide 14b is short and bent upward.

  When the buffer B is formed on the sheet 9 between the gate member 3 and the feed roller pair 4 at the downstream end in the transport direction of the feed roller upper transport guide 14b, the height of the buffer is kept below a certain level. In order to suppress, the auxiliary guide 15 which is somewhat curved is fixed to a holder 26 provided on the upper feed guide 14b. Thereby, the gap of the conveyance path between the auxiliary guide 15 and the lower conveyance guide 14a of the feed roller part is made wider than the gap of the conveyance path in the feed roller part and the shift roller part, and the gate member 3 and the feed roller pair 4 The buffer B is easily formed on the paper 9 between the two.

Further, the shift roller unit lower conveyance guide 12a and the shift roller unit upper conveyance guide 12b are independent of the conveyance guides of other parts, and the shift roller unit lower conveyance guide 12a and the shift roller unit upper conveyance guide 12b are aligned. The shift roller pair 2 and the shift roller pair 2 can be moved in a direction perpendicular to the sheet conveyance direction.

In such a conventional printing apparatus, when the recording medium alignment mechanism unit transports a sheet with low rigidity such as thin paper or a sheet with a curled tip, the gap between the transport paths of the auxiliary guide unit is large. 4, in the process of transporting the sheet 9 toward the gate member 3, the leading end of the sheet is easily lifted by the momentum during transport, and the lifted leading end of the sheet is, as shown in FIG. 7, the entrance of the shift roller unit upper transport guide 12 b. There is a problem that a jam may occur due to being caught on the upper side or jumping out from the gap between the shift roller upper conveyance guide 12b and the auxiliary guide 15.

  The present invention has been made to solve such a problem. In the recording medium alignment mechanism of the printing apparatus, recording is performed during conveyance between the feed roller and the gate member regardless of the rigidity of the conveying medium. Prevents the occurrence of transport jams due to the rising of the leading edge of the medium, and ensures the followability of the leading edge of the recording medium to the gate member by forming a buffer of the recording medium between the gate member and the feed roller, and high recording medium running The purpose is to achieve both stability.

The printing apparatus according to the present invention includes a recording medium storage unit that stores a recording medium, a printing unit that prints an image on the recording medium, and a recording that conveys the recording medium that is sent one by one from the recording medium storage unit to the printing unit. A recording medium alignment mechanism for correcting the posture of the recording medium to be conveyed upstream of the printing unit in the recording medium conveyance path in the recording medium conveyance direction. The mechanism portion arranges a shift roller pair and a feed roller pair, each of which includes a drive roller and a driven roller, which can be contacted and separated , at a predetermined interval on the downstream side and the upstream side in the recording medium conveyance direction. retracting position to permit passage of the recording medium conveyance direction downstream side of the recording medium is inserted into the conveying path evacuated to a recording medium from the protruding position and the recording medium conveying path to prevent passage of the recording medium relative pairs The printing apparatus and a displaceable gate member in bets, in order to achieve the above object, is characterized by being configured as follows.

That is, the recording medium conveyance guide on the shift roller pair side forming the recording medium conveyance path in the recording medium alignment mechanism section and the recording medium conveyance guide on the feed roller pair side are provided separately, and the feed roller opposite side A part of the upper recording medium conveyance guide on the downstream side in the recording medium conveyance direction as an auxiliary guide that can be rotated to a position that widens and narrows a gap that forms a recording medium conveyance path with the lower recording medium conveyance guide With composition
A part of the upper recording medium conveyance guide on the shift roller opposite side on the upstream side in the recording medium conveyance direction is configured as a rotatable rotation guide part, and an end of the rotation guide part on the upstream side in the recording medium conveyance direction is formed. A position where the auxiliary guide is brought into contact with the lower surface of the free end portion on the downstream side in the recording medium conveyance direction, and the auxiliary guide is rotated by the rotation guide portion to narrow and widen the gap forming the recording medium conveyance path; It was comprised so that it might rotate.

When the recording medium is conveyed toward the shift roller pair and the gate member by displacing the gate member to the projecting position and separating the shift roller pair, the feed roller pair is pressed against the shift roller pair and the gate member. Then, the auxiliary guide is rotated by the rotating guide portion to a position that narrows the gap forming the recording medium conveyance path, the front end of the recording medium is abutted against the gate member, and then the recording is performed by the feed roller pair. When the buffer is formed on the recording medium between the gate member and the feed roller pair by over-conveying the medium, the rotation guide portion causes the auxiliary guide to widen the gap that forms the recording medium conveyance path. A means for rotating is provided.

  The means for rotating the auxiliary guide by the rotation guide portion is fixed to a cam shaft common to a cam for controlling the contact and separation operation of the feed roller pair and a cam for controlling the displacement operation of the gate member. A cam for controlling the contact / separation operation of the shift roller pair and the cam surface of the cam are always in contact with the cam. The feed roller pair is brought into contact with and separated from the cam and the rotation guide portion is rotated. It is preferable that the lever has a driving piece to be driven.

  The means for rotating the auxiliary guide by the rotation guide unit is also a direction in which the rotation guide unit widens a gap that forms a recording medium conveyance path between the rotation guide unit and the lower recording medium conveyance guide on the shift roller opposite side. The auxiliary guide may be rotated to a position where a gap for forming a recording medium conveyance path is widened between the auxiliary guide and the lower recording medium conveyance guide on the opposite side of the feed roller.

Furthermore, means for rotating the auxiliary guide by the rotation guide portion, the auxiliary guide may be rotated to a plurality of positions as a position to extend the gap to form the recording medium conveying path.
The means for rotating the auxiliary guide by the rotation guide part has a cam surface of a cam for controlling the contact / separation operation of the shift roller pair in a plurality of stages. You may make it rotate a guide to several positions as a position which expands the clearance gap which forms the said recording-medium conveyance path.

In the printing apparatus according to the present invention, as described above, the recording medium alignment mechanism unit control method includes a portion of the upper recording medium conveyance guide on the opposite side of the feed roller on the downstream side in the recording medium conveyance direction between the lower recording medium conveyance guide. As an auxiliary guide that can be turned to a position that widens and narrows the gap that forms the recording medium conveyance path, the upper recording medium conveyance guide on the opposite side of the shift roller rotates a part on the upstream side in the recording medium conveyance direction. In the printing apparatus, which is configured as a possible rotation guide portion, and an end portion on the upstream side in the recording medium conveyance direction of the rotation guide portion is brought into contact with the lower surface of the free end portion on the downstream side in the recording medium conveyance direction of the auxiliary guide. A recording medium alignment mechanism control method,
The rotation guide part is rotated in the separated state of the shift roller pair,
When the recording medium is conveyed toward the shift roller pair and the gate member by pressing the feed roller pair in a state where the gate member is displaced to the blocking position and the shift roller pair is separated, The auxiliary guide is rotated by the rotating guide portion to a position that narrows the gap forming the recording medium conveyance path, the front end of the recording medium is abutted against the gate member, and then the recording medium is moved by the feed roller pair. in forming the buffer to the recording medium between the gate member and the feed roller pair and over conveyor, the position twice to widen the gap of the auxiliary guide to form said recording medium conveying path by the rotation guide portion It is made to move.

  Three cams fixed to a common camshaft respectively make contact / separation operation of the shift roller pair, displacement operation of the gate member, contact / separation operation of the feed roller pair, and rotation of the rotation guide portion. It is preferable to control the rotation of the auxiliary guide by movement in conjunction with each other.

  According to the present invention, in the recording medium alignment mechanism portion of the printing apparatus, the upstream portion of the auxiliary conveyance guide and the upper conveyance guide of the shift roller portion can be rotated in the recording medium conveyance direction, and in a series of posture correction operations of the recording medium. Regardless of the rigidity of the recording medium, the recording medium is aligned by increasing or decreasing the clearance of the auxiliary guide conveyance path in conjunction with the position switching operation of the gate member and the separation / pressing operation of the shift roller pair and the feed roller pair. The lift of the recording medium front end in the auxiliary guide section conveyance path of the mechanism section is suppressed, and jamming due to catching of the shift roller section at the recording medium front end to the conveyance guide entrance or jumping out of the gap is prevented, and as a result, the gate member The follow-up to the gate member at the leading edge of the recording medium is ensured by forming a buffer on the recording medium between the feed roller pair and the feed roller pair. Realization of high recording medium running stability in the recording medium aligning mechanism becomes possible.

1 is a diagram showing a schematic configuration of a recording medium conveyance path in an embodiment of a printing apparatus according to the present invention. FIG. 2 is a mechanism diagram illustrating a configuration example of a recording medium alignment mechanism unit in FIG. 1. It is a mechanism figure which similarly shows the different operation | movement state. FIG. 3 is a sequence diagram showing the operation of each part of the recording medium alignment mechanism shown in FIGS. 1 and 2 as the cam shaft rotates. FIG. 2 is a schematic diagram illustrating a simplified printing apparatus main body 100 illustrated in FIG. 1. It is a mechanism figure which shows the structure of the recording medium alignment mechanism part in the conventional printing apparatus. It is a figure for demonstrating the problem similarly. FIG. 7 is a sequence diagram illustrating changes in the operating state of the gate member, the shift roller pair, and the feed roller pair in a series of recording medium alignment operations by the recording medium alignment mechanism unit illustrated in FIG. 6 .

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
[Recording medium conveyance path in printing apparatus]
FIG. 1 is a diagram showing a schematic configuration of a recording medium conveyance path in an embodiment of a printing apparatus according to the present invention. The printing apparatus includes a printing apparatus main body 100 and a mass feeding apparatus 200. In the printing apparatus main body 100, a paper tray 10 (actually provided in a plurality of stages, but shown in a simplified manner) that is a recording medium storage unit that stores paper as a recording medium, and one sheet is fed from the tray. And a sheet conveyance path 7 which is a recording medium conveyance path for conveying a sheet to be printed to a printing unit (image forming unit) (not shown). The printing unit prints images such as characters and graphics on the conveyed paper. Hereinafter, in the description of this embodiment, the recording medium is described as “paper”, but the recording medium includes various types of printable films and sheets.

Each of the paper conveyance paths 7 is formed by a guide plate or the like, and a paper feeding path 7a for feeding the paper 9 as a recording medium from the paper tray 10 and a double-sided conveyance for reversing the paper printed on one side. Sheet conveyance path 7b, curve-shaped conveyance path 7c, and straight-shaped conveyance path 7d for carrying in a sheet from the outside, and the sheet on the downstream side by sheet alignment mechanism section 1 which is a recording medium alignment mechanism section according to the present invention. A conveyance path is provided. The curve-shaped conveyance path 7 c and the straight-shaped conveyance path 7 d merge at point A on the upstream side of the feed roller pair 4 of the sheet alignment mechanism unit 1.

  A pair of pickup roller 71 and paper feed roller 72 and separation roller 73 is provided near the entrance of the paper feed path 7a, and a pair of transport rollers 74 is provided near the exit. The curved conveyance path 7c is provided with conveyance roller pairs 75 and 76, and the straight conveyance path 7d is provided with a conveyance roller pair 77. The conveyance roller pairs 76 and 77 are each composed of a drive roller and a driven roller. Can be pressed against and separated from the drive roller, and is urged by springs 78 and 79 in the direction of pressure contact.

  On the other hand, in the large-volume paper feeder 200, a large-volume paper tray 11 (actually a plurality of large-sized paper trays are provided in a simplified manner), which is a recording medium storage unit, and the large-volume paper tray 11 A sheet feeding path 8 for feeding the sheet 9 as a recording medium fed one by one to the straight-shaped conveyance path 7d of the printing apparatus main body 100 is provided. A pair of a pickup roller 81, a paper feed roller 82, and a separation roller 83 is provided near the entrance of the paper feed path 8, a pair of transport rollers 84 is provided on the downstream side, and a pair of transport rollers 85 is provided near the exit. Yes. The conveying roller pair 85 includes a driving roller and a driven roller. The driven roller can be pressed against and separated from the driving roller and is urged by a spring 86 in a pressing direction.

The sheet alignment mechanism 1 will be described in detail with reference to FIGS. 2 and 3. In FIG. 1, a shift roller pair 2, a gate member 3, a feed roller pair 4, a detection sensor 5 similar to the conventional example shown in FIG. Only the shift roller unit conveyance guide 12, the feed roller unit conveyance guide 14, the auxiliary guide 15 and the like are shown in a simplified manner.
The distance between each pair of adjacent transport rollers and between the feed roller pair 4 and the shift roller pair 2 is a distance that can transport even a minimum size sheet, for example, about 150 mm to 180 mm.

The uppermost sheet 9 is fed from the sheet tray 10 in the printing apparatus main body 100 to the sheet feeding path 7a by the pickup roller 71, separated into one sheet by the sheet feeding roller 72 and the separation roller 73, and conveyed. It is sent to the curve-shaped conveyance path 7c by the roller pair 74. Alternatively, a sheet printed on one side by a printing unit (not shown) is reversed and sent from the duplex conveyance path 7b to the curved conveyance path 7c. Any one of these sheets is conveyed in the curve-shaped conveyance path 7c by the conveyance roller pairs 75 and 76, and is sent to the sheet alignment mechanism unit 1 through the point A.

In addition, the uppermost sheet 9 is fed from the large-volume sheet tray 11 of the large-volume sheet feeding device 200 to the sheet feeding path 8 by the pickup roller 81 , and separated and fed by the sheet feeding roller 82 and the separation roller 83. Then, the sheet is fed into the straight-shaped conveyance path 7d of the printing apparatus main body 100 by the conveyance roller pairs 84 and 85. The sheet can be transported by the transport roller pair 77 of the straight-shaped transport path 7d and sent to the sheet aligning mechanism unit 1 through the point A.
These are selected according to the designated paper, print mode, and the like.

The basic configuration of the sheet alignment mechanism unit 1 and the sheet posture correction operation are substantially the same as those of the conventional example described above, but the upstream guide part of the upper guide of the auxiliary guide 15 and the shift roller unit guide 12 in the sheet transport direction. Are supported so that each free end thereof is engaged, and during a series of paper alignment operations, they are rotationally displaced, and the paper 9 is moved between the feed roller pair 4 and the shift roller pair 2. The difference is that the gap of the auxiliary guide section conveyance path that forms the curved buffer B is widened or narrowed.

[ Recording medium alignment mechanism]
2 and 3 are mechanism diagrams showing a configuration example of the sheet aligning mechanism unit 1 which is a recording medium aligning mechanism unit, and portions corresponding to those in FIGS. 6 and 7 are denoted by the same reference numerals.
The configuration of the sheet alignment mechanism unit 1 other than the portions related to the shift roller unit conveyance guide 12 and the auxiliary guide 15 is the same as the configuration described with reference to FIGS. This will be described in detail.

The shift roller pair 2 and the feed roller pair 4 are each composed of a lower drive roller and an upper driven roller, and each axis thereof is fixed in parallel to a side plate (not shown) on the front side and the back side in the drawing. However, the driven roller is supported by the drive roller so as to be capable of being pressed and separated, and is urged by springs 31 and 32 in the direction of pressing the drive roller.
An opening is formed in the shift roller section conveyance guide 12 so that the shift roller pair 2 can be pressed and separated in the sheet conveyance path of the gap, and the gate member 3 has a comb-like gate at the tip. A plurality of slots into which the pieces 3a are inserted are also formed.

The shift roller unit conveyance guide 12 is constituted by a shift roller unit lower conveyance guide 12a, a divided fixed guide unit 12c and a rotation guide unit 12d of the shift roller unit upper conveyance guide. That is, the shift roller unit upper conveyance guide includes a fixed guide portion 12c on the downstream side in the sheet conveyance direction and a rotation guide portion 12d on the upstream side, and is fastened by a shaft member or the like at the rotation fulcrum 23.

The downstream fixed guide portion 12c is fixed to a side plate (partially indicated by a broken line) 22, but a support pin 25 is provided at a side end portion of the upstream rotation guide portion 12d. Is inserted into a long hole 24 provided in the side plate 22. The long hole 24 is formed in an arc shape centered on the rotation fulcrum 23. Therefore, the rotation guide portion 12 d can rotate in the direction indicated by the arrow D within the range of the long hole 24 around the rotation fulcrum 23.

The feed roller unit conveyance guide 14 is configured by a feed roller unit lower conveyance guide 14a and a feed roller unit upper conveyance guide 14b, and an opening is formed so that the feed roller pair 4 can be pressed and separated in the paper conveyance path of the gap. Has been.
A pair of holders 16 are fixed to both ends in the width direction with respect to the sheet conveyance path of the support piece 14c where the downstream end of the feed roller upper conveyance guide 14b is bent upward, and the pair of holders A shaft hole is formed in each 16.

On the other hand, the auxiliary guide 15 covers substantially the entire area on the sheet conveyance path between the downstream end of the feed roller upper conveyance guide 14b and the upstream end of the rotation guide 12d of the shift roller upper conveyance guide. In addition, it is formed of resin in a shape that is curved upwards somewhat along the paper conveyance direction. Pins 15 a protrude from both side surfaces of the auxiliary guide 15 on the upstream side in the sheet conveying direction, and the pins 15 a are loosely fitted into the shaft holes of the pair of holders 16, respectively.
Therefore, the auxiliary guide 15 is supported by the holder 16 so as to be rotatable in the direction of arrow E with the pin 15a as a fulcrum. This auxiliary guide 15 constitutes the downstream portion of the feed roller upper transport guide 14b.

Further, the upstream end portion of the rotation guide portion 12d of the shift roller portion conveyance guide 12 mentioned above is brought into contact with the lower surface of the free end portion of the auxiliary guide 15 on the downstream side in the sheet conveyance direction. The contact state is always maintained by the weight of the guide 15.
Therefore, the auxiliary guide 15 can be rotated to a position for narrowing and a space for forming a paper conveyance path between the auxiliary guide 15 and the lower conveyance guide 14a by the rotation of the rotation guide portion 12d . Note that the auxiliary guide 15 may be biased by a spring so as to always provide left-hand turning ability in FIG.

  The shift roller separation lever 20 has an upper end portion rotatably supported on the side plate 22 by a shaft 41, and a driving piece 20a extending below the shaft 2a of the driven roller of the shift roller pair 2 is fixed to the upper end portion. is doing. As shown in FIG. 2, when the large diameter portion of the cam surface 18 a of the shift roller separation cam 18 is in contact with the shift roller separation lever 20, the shift roller separation lever 20 turns right about the shaft 41. The driving piece 20a pushes up the shaft 2a against the urging force of the spring 31, and the driven roller of the shift roller pair 2 is separated from the driving roller so that the sheet is not conveyed.

At this time, the shift driving piece 20a of the roller separation lever 20, and the rotation support portion of the rotation guide portion 12d of the shift roller unit conveyance guide 12 by bending to the left down on the extended by a lever piece 12e, times As shown in FIG. 2, the moving guide portion 12d is turned to the left, the auxiliary guide 15 is turned to the right against its own weight, and a gap that forms a sheet conveyance path with the lower conveyance guide 14a of the feed roller portion. Set the position to widen.
In this embodiment, the large-diameter portion of the cam surface 18a of the shift roller separation cam 18 is formed in a plurality of stages having different distances from the cam shaft 6, so that the rotation guide portion by the rotation of the shift roller separation lever 20 is formed. The rotation amount of 12d is varied, and the auxiliary guide 15 is rotated in accordance with the rotation amount of the rotation guide portion 12d , so that the positions for widening the gaps forming the paper conveyance path can be set to a plurality of different positions.

When the shift roller separation cam 18 rotates in the direction indicated by the arrow C and the large diameter portion of the cam surface 18a does not come into contact with the shift roller separation lever 20, the shaft 2a and the drive piece are driven by the biasing force of the spring 31. 20a is pushed down, the shift roller separation lever 20 rotates counterclockwise, and the driven roller of the shift roller pair 2 comes into pressure contact with the drive roller as shown in FIG.
At this time, since the drive piece 20a of the shift roller separation lever 20 releases the lever piece 12e of the rotation guide portion 12d , the auxiliary guide 15 is lowered by turning left while rotating the rotation guide portion 12d by its own weight. This is the position to narrow the gap forming the paper transport path .

  An intermediate portion of the feed roller separation lever 21 is rotatably supported by a side plate by a shaft 42, and a tip portion thereof is bent and extends below the shaft 4 a of the driven roller of the feed roller pair 4. As shown in FIG. 2, when the large diameter portion of the cam surface of the feed roller separation cam 19 is not in contact with the feed roller separation lever 21, the feed roller separation lever 21 is fed by a biasing means (not shown). It is turned right so as to follow the roller separation cam 19, and its tip is separated from the shaft 4a. Therefore, the shaft 4a is pushed down by the urging force of the spring 32, and the driven roller of the feed roller pair 4 is in pressure contact with the driving roller, so that the sheet can be conveyed.

  From this state, when the feed roller separation cam 19 rotates in the direction of arrow C and the large diameter portion of the cam surface comes into contact with the feed roller separation lever 21 as shown in FIG. Rotates counterclockwise about the shaft 42, and the tip of the shaft 4a pushes up the shaft 4a against the urging force of the spring 32, and the driven roller of the feed roller pair 4 is separated from the driving roller so that the paper is not conveyed. To do.

The gate member 3 is provided with a lever portion 3b that is substantially parallel to the sheet conveyance direction and is bent upward from a side end of the intermediate portion thereof, which is bent at a substantially right angle from a gate piece 3a having a comb-like tip. The support piece 3c is rotatably supported on the side plate 22 by a shaft 43. The end of the lever portion 3b opposite to the gate piece 3a extends to a position where it can come into contact with the gate switching cam 17. As shown in FIG. 2, when the large diameter portion of the cam surface of the gate switching cam 17 is not in contact with the lever portion 3b, the lever portion 3b is rotated clockwise by the urging force of the spring 33, and the gate piece 3a is in a protruding position that protrudes into the paper conveyance path in the shift roller unit conveyance guide 12, and is in a state in which the leading edge of the conveyed paper can be locked.

  From this state, when the gate switching cam 17 rotates in the direction of arrow C and the large diameter portion of the cam surface comes into contact with the lever portion 3b of the gate member 3 as shown in FIG. The gate piece 3a is turned to the left against the urging force of the spring 33, so that the gate piece 3a is retracted from the sheet conveyance path in the shift roller section conveyance guide 12, and the sheet can pass therethrough.

On the upstream side of the feed roller pair 4 in the paper conveyance direction, a photosensor 28 for detecting double feed comprising a light emitting portion and a light receiving portion facing each other across the paper conveyance path by the feed roller portion conveyance guide 14 is disposed. Of course, the feed roller section conveyance guide 14 is formed so as not to obstruct the optical path of the photosensor 28.
In this embodiment, the gate switching cam 17, the shift roller separation cam 18, the feed roller separation cam 19, and the feed roller separation lever 21 are made of resin, the shift roller separation lever 20 is made of aluminum die casting, and the gate member 3 is made of sheet metal. It is built.

  The order of the paper transport position correction and the meandering (tilt) correction operation in the paper alignment mechanism unit 1 is the same as that described in the background art. That is, as shown in FIG. 2, the shift roller pair 2 is separated before the leading edge of the sheet 9 reaches the shift roller pair 2, and the gate member 3 has the gate piece 3 a inserted into the shift roller section conveyance guide 12. Then, the sheet conveyance path is raised to the protruding position. The pair of feed rollers 4 conveys the sheet in a pressure contact state, and presses the sheet 9 against the gate member 3 while decelerating the conveyance speed immediately before the leading end of the sheet 9 abuts against the gate member 3 to overconvey.

  As a result, a buffer B in which the sheet 9 is curved upward is formed between the gate member 3 and the feed roller pair 4 as shown by a one-dot chain line in FIG. 2, and the leading end of the sheet 9 extends along the gate member 3. After correcting the meandering (inclination), the shift roller pair 2 holds the sheet in pressure contact.

  Subsequently, the gate member 3 is lowered and retracted from the conveyance path in the shift roller unit conveyance guide 12, and the sheet 9 is conveyed by the shift roller pair 2 while the feed roller pair 4 is separated and the buffer B is released. When the paper 9 reaches the detection sensor 5, the detection sensor 5 detects the position of the end portion (side end portion) of the paper 9 in the main scanning direction, and the reference in the main scanning direction of the paper 9 from the detected information. The shift direction and shift amount with respect to the position are calculated. The shift roller pair 2 is moved in the direction (main scanning direction) perpendicular to the sheet conveying direction together with the shift roller unit conveying guide 12 by the amount of deviation in the direction opposite to the calculated deviation direction, so Correct the position.

  After that, after the position-corrected sheet 9 is nipped by a roller pair (not shown) on the downstream side of the shift roller pair 2, the shift roller pair 2 is separated again to bring the gate member 3 to the position for closing the sheet conveyance path again. The feed roller pair 4 is brought into pressure contact again to prepare for the next sheet.

As the detection sensor 5 for detecting the deviation in the main scanning direction of the paper, as described in Patent Document 1, various sensors such as a CIS sensor, a CCD linear image sensor, and a plurality of photocouplers, which are contact image sensors, are used. However, if the CIS sensor is used, it is possible to easily detect the deviation direction and the deviation amount of the paper with an accuracy corresponding to the resolution.
Although the feed roller pair 4 is moved in the main scanning direction by the pressing force of the cam and the spring, the mechanism is the same as in the prior art, and the description thereof is omitted.

In the recording medium alignment mechanism control method according to the present invention, with respect to the movement of the position of the auxiliary guide 15 during the sheet alignment operation, the gate member 3 is raised to the protruding position that closes the sheet conveyance path, and the feed roller pair 4 is pressed. At the timing when the sheet 9 is conveyed toward the gate member 3, the auxiliary guide 15 is moved in a direction to narrow the gap of the auxiliary guide portion conveyance path. Subsequently, at the timing at which the leading edge of the sheet 9 is pressed against the gate member 3 to carry it over and the buffer B is formed on the sheet 9 between the gate member 3 and the feed roller pair 4, as shown in FIG. The auxiliary guide 15 is moved in a direction to widen the gap in the conveyance path.

As a result, the lifting of the sheet in the auxiliary guide section conveyance path is suppressed, the leading edge of the sheet is caught on the entrance end of the upper conveyance guide of the shift roller section, and the gap is formed between the shift roller section upper conveyance guide and the auxiliary guide 15. To prevent the occurrence of jamming due to the above, and to form a suitable buffer on the paper between the gate member 3 and the feed roller 4 to correct the posture and realize paper running stability. And become possible.

  The three cams of the gate switching cam 17, the shift roller separation cam 18, and the feed roller separation cam 19 are provided on the common cam shaft 6, and the auxiliary guide 15 is rotated by the rotation of the cam shaft 6 in the direction of arrow C. The main part of the means for performing the position switching in conjunction with the position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4 is constituted. The cam shaft 6 is rotated by a motor whose drive is controlled by a control unit (not shown).

FIG. 4 shows a sequence of the position switching operation of the gate member 3, the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4, and the position switching operation of the auxiliary guide 15. The horizontal axis represents the rotational phase (angle) of the cam shaft 6 and represents a sequence of one rotation (360 ° rotation).
In FIG. 4, at the home position (HP) where the rotation angle of the cam shaft 6 is 0 °, the gate member 3 is in the retracted position, the shift roller pair 2 is in a separated state, and the feed roller pair 4 is in a pressure contact state. The auxiliary guide 15 is at the reference position.

The state shown in FIG. 2 is a state in which the rotation angle of the cam shaft 6 in FIG. 4 is in the vicinity of α °, and the state shown in FIG. 3 is a state in which the rotation angle of the cam shaft 6 is in the vicinity of β °.
4, the auxiliary guide 15 moves in two steps from the standard position to positions 1 and 2 above the standard position (positions that make the paper conveyance path gap wider than the standard interval) in the angle range indicated by U. it can.

In this embodiment, the large-diameter portion of the cam surface 18a of the shift roller separating cam 18 is formed in three stages having different distances from the cam shaft 6 to assist the shift roller pair 2 in a separated state. The guide 15 can be rotated to a standard position (a position for narrowing the gap in the auxiliary guide part conveyance path) and an upper position 1 and 2 (a position for widening the gap in the auxiliary guide part conveyance path).
It should be noted that the upper position can be changed to three or more stages by changing the shape of the large diameter portion of the cam surface 18a of the shift roller separating cam 18 .

Regarding the position switching of the auxiliary guide 15 when the buffer B is formed between the gate member 3 and the feed roller pair 4, there is a difference in the buffer formation height even when the buffer amount is the same between the low-rigidity paper and the high-quality paper (stiffness). Rotation of the shift roller separation cam 18 so that the gap in the auxiliary guide section conveyance path is wider when the high-stiffness paper buffer is formed than when the low-stiffness paper buffer is formed. It is possible to switch the height position of the auxiliary guide 15 by changing the phase.

In this case, as in the above-described embodiment, the auxiliary guide 15 is used for printing when the auxiliary guide 15 has a plurality of positions as positions for widening the gap of the paper conveyance path formed between the feed roller portion lower conveyance guide 14a. Depending on the rigidity of the recording medium, the auxiliary guide 15 may select a plurality of positions that widen the gaps forming the paper conveyance path.
The plurality of positions can be set by the shape of the cam surface 18a of the shift roller separation cam 18 that rotates the shift roller separation lever 20 as described above.

Regarding the paper stiffness determination method, for example, a paper stiffness rank table is created in advance using a matrix of various paper types and paper thicknesses and stored in the memory of the control unit. The CPU of the control unit can make a determination with reference to the table based on the condition of the sheet type and the sheet thickness to be performed.

Alternatively, the light transmittance from the light emitting portion to the light receiving portion is detected by using a photo sensor 28 for detecting double feed provided on the upstream side of the feed roller pair 4, and the paper type and paper thickness are determined based on the detection result. It is conceivable to recognize and determine the paper rigidity rank. The photo sensor 28 or another photo sensor may be provided near the exit of the paper tray 10 to recognize the paper type and paper thickness immediately after the start of paper feeding.
The thickness of the sheet is generally expressed in g / ^{m 2,} with 220 g / ^{m 2} or more Heavyweight, generally higher stiffness, at 100 g / ^{m 2} or less light soy, generally less rigid.

As described above, the gap in the conveyance path of the auxiliary guide unit in the sheet alignment mechanism unit 1 is used for the position switching operation of the gate member 3 and the separation / pressure contact operation of the shift roller pair 2 and the feed roller pair 4 in a series of sheet alignment operations. By increasing and decreasing in conjunction with each other, the feed roller pair 4 feeds the sheet to the gate member while ensuring followability of the leading end of the sheet to the gate member 3 by forming the sheet buffer between the gate member 3 and the feed roller pair 4. Therefore, it is possible to suppress the occurrence of jamming due to the sheet tip portion floating in the auxiliary guide portion conveyance path when conveying toward the sheet 3.

In the above-described embodiment, the shift roller separation cam 18 and the shift roller separation lever 20 for controlling the separation / contact of the shift roller pair 2 are also used for the position control of the auxiliary guide 15, so that a new dedicated cam or lever is used. There is also an advantage that it can be implemented at low cost.

  [Overall configuration of printing device]

Here, the overall configuration of an embodiment of the printing apparatus according to the present invention will be briefly described.
FIG. 5 is a schematic diagram showing the printing apparatus (image forming apparatus) main body 100 shown in FIG. 1 in a simplified manner, and parts corresponding to those in FIG. Although the paper feed roller 72, the separation roller 73, the conveyance roller pair 74 , and the like in FIG. 1 are not shown, they actually exist.

The printing apparatus main body 100 includes a tandem intermediate transfer type color printing unit, and the portion surrounded by a broken line is the above-described sheet alignment mechanism unit 1. In this printing apparatus main body 100, color printing (color image formation) is performed on a sheet that is a recording medium that is conveyed through the above-described sheet conveying path, and whose posture is corrected by the sheet aligning mechanism unit 1 and sent out. Various members constituting the printing section are provided.

In the upper part, photosensitive drums 101Y, 101C, 101M, and 101K as image carriers constituting a color image forming unit, charging rollers 110Y, 110C, 110M, and 110K and optical writing around each photosensitive drum. An irradiation unit for image writing laser light of each color by the device 102 and developing devices 103Y, 103C, 103M, and 103K are provided. Y, C, M, and K indicate yellow, cyan, magenta, and black, respectively, corresponding to the development color of each image that is attached to each code.

Further, an intermediate transfer belt, which is an intermediate transfer body, is formed by a pair of driving rollers 111, a driven roller 112, and a lower secondary transfer counter roller 113 so as to be in contact with the respective lower end surfaces of the photosensitive drums 101Y, 101C, 101M, and 101K. 104 is stretched, a suitable tension is applied by the tension roller 114.

  A secondary transfer roller 115 is disposed at a position facing the secondary transfer counter roller 113 and the intermediate transfer belt 104, and a secondary transfer portion is formed by a nip portion between the secondary transfer roller 115 and the intermediate transfer belt 104. Is configured. The secondary transfer unit corresponds to the path of the sheet conveyed from the sheet alignment mechanism unit 1.

A sheet conveying belt 106 is provided on the downstream side of the secondary transfer unit, and a fixing device 107 is further provided on the downstream side thereof. Wearing the discharge tray 120 on the side for discharging the printed sheet of the printing apparatus main body 100. However, instead of the paper discharge tray 120, a sorter or a post-processing device for aligning and stacking printed sheets one by one or stapling may be connected. Needless to say, the mass feeding device 200 shown in FIG. 1 can be connected to the right side surface in FIG.

In the printing apparatus main body 100, the surfaces of the photosensitive drums 101Y, 101C, 101M, and 101K are uniformly charged by the charging rollers 110Y, 110C, 110M, and 110K, and then each color image writing laser beam by the optical writing apparatus 102 is obtained. 5, each photoconductive drum 101 </ b> Y, 101 </ b> C, 101 </ b> M, 101 </ b> K is rotated leftward in FIG. 5 while being scanned in the main scanning direction (perpendicular to the paper surface). An image is formed.

The electrostatic latent images on the photosensitive drums 101Y, 101C, 101M, and 101K are developed by the developers of the colors of the developing devices 103Y, 103C, 103M, and 103K, and toner images of yellow, cyan, magenta, and black are used. Is formed. Then, the toner on the photosensitive drums 101Y, 101C, 101M, a voltage is applied to the primary transfer roller (not shown) face each other across the 101K and the intermediate transfer belt 104, the photosensitive drums 101Y, 101C, 101M, 101K The images are sequentially transferred onto the intermediate transfer belt 104 that rotates in the direction indicated by the arrow, thereby forming a full-color toner image.

  In accordance with the timing when the full-color toner image on the intermediate transfer belt 104 in the printing unit reaches the secondary transfer unit 105, the sheet that has passed through the sheet alignment mechanism unit 1 is conveyed to the secondary transfer unit, and the secondary transfer roller By applying a voltage to 115, the full-color toner image on the intermediate transfer belt 104 is transferred onto the paper. The sheet is conveyed to the fixing device 107 by the sheet conveying belt 106, where heat and pressure are applied to fix the toner image on the sheet. The paper on which printing has been completed in this manner is conveyed by a paper discharge roller (not shown) and discharged onto a paper discharge tray 120 outside the apparatus.

  When printing on both sides of a sheet, the fixing device 107 switches the conveyance path of the sheet on which the toner image is fixed on one side, and reverses the front and back to the duplex conveyance path 7b shown in FIG. From there, the paper is fed again by the printing unit through the curved conveyance path 7c and the sheet aligning mechanism unit 1 to form an image on the other side.

In this embodiment, an example in which the printing unit is a tandem type intermediate transfer type color printing unit has been described. However, the present invention is not limited to this, and a tandem type direct transfer type color printing unit may be a color printing unit other than the tandem type. Alternatively, a printing unit that forms a monochrome image may be used. Furthermore, the present invention is not limited to an electrophotographic printing apparatus, and can also be applied to an inkjet printing apparatus.
This invention is not limited to the embodiments and modifications described above, it is needless to say that other than the requirements as defined in the following claims may be variously modified.

  The present invention can be applied to various printing apparatuses using an image forming apparatus such as a laser printer or an ink jet printer, and is particularly suitable for a commercial printing apparatus provided with a recording medium alignment mechanism in the recording medium conveyance path.

1: Paper alignment mechanism (recording medium alignment mechanism) 2: Shift roller pair 3: Gate member 4: Feed roller pair 5: Detection sensor 6: Common cam shaft 7: Paper transport path 7a: Paper feed path 7b: Double-sided conveyance path 7c: Curve-shaped conveyance path 7d: Straight-shaped conveyance path 8: Paper feed path 9: Paper (recording medium) 10: Paper tray 11: Large-volume paper tray 12: Shift roller section conveyance guide 12a: Below shift roller section Side transport guide
12c : Fixed guide portion of the shift roller portion upper side conveyance guide
12d : Rotation guide part 12e of shift roller part upper side conveyance guide 12e: Lever piece 13: Paper conveyance path 14 downstream of the pair of shift rollers 14: Feed roller part conveyance guide 14a: Feed roller part lower conveyance guide 14b: Feed roller part upper side Transport guide 15: Auxiliary guide 15a: Pin 16, 26: Holder 17: Gate switching cam 18: Shift roller separation cam 18a: Cam surface 19: Feed roller separation cam 20: Shift roller separation lever 21: Feed roller separation lever 22: Side plate 23: rotation fulcrum of rotation guide section 24: long hole 25: support pin 28: photosensor 31 to 33: spring 41 to 43: axis
71, 81: Pickup roller 72, 82: Paper feed roller 73, 83: Separation roller 74-77, 84, 85: Pair of conveyance rollers
78 , 79 , 86: Spring 100: Printing device main body 200: Mass feeding device 101Y, 101C, 101M, 101K : Photosensitive drum 102: Optical writing device 103Y, 103C, 103M, 103K: Developing device 104: Intermediate transfer belt 105 : Secondary transfer unit 106: Paper transport belt 107: Fixing device 110Y, 110C, 110M, 110K: Charging roller 113: Secondary transfer counter roller 115: Secondary transfer roller 120: Paper discharge tray

JP 2008-50069 A

Claims (8)

A recording medium storage unit that stores the recording medium, a printing unit that prints an image on the recording medium, and a recording medium conveyance path that conveys the recording medium sent out one by one from the recording medium storage unit to the printing unit, A recording medium alignment mechanism for correcting the posture of the recording medium to be conveyed, upstream of the printing unit in the recording medium conveyance path in the recording medium conveyance direction;
The recording medium aligning mechanism section includes a shift roller pair and a feed roller pair, each of which includes a driving roller and a driven roller, which can be brought into contact with and separated from each other at predetermined intervals on the downstream side and the upstream side in the recording medium conveyance direction. And a protruding position for blocking the passage of the recording medium by being inserted into the recording medium conveyance path on the downstream side in the recording medium conveyance direction with respect to the pair of shift rollers, and allowing the recording medium to pass by retreating from the recording medium conveyance path. In a printing apparatus comprising a gate member that can be displaced to a retracted position,
A recording medium conveyance guide on the shift roller pair side that forms a recording medium conveyance path in the recording medium alignment mechanism section and a recording medium conveyance guide on the feed roller pair side are provided separately, and an upper side on the feed roller pair side A part of the recording medium conveyance guide on the downstream side in the recording medium conveyance direction is configured as an auxiliary guide that can be rotated to a position that widens and narrows a gap that forms a recording medium conveyance path with the lower recording medium conveyance guide. With
A part of the upper recording medium conveyance guide on the opposite side of the shift roller on the upstream side in the recording medium conveyance direction is configured as a rotatable rotation guide part, and the end of the rotation guide part on the upstream side in the recording medium conveyance direction is formed. A position where the auxiliary guide is brought into contact with the lower surface of the free end on the downstream side in the recording medium conveyance direction, and the auxiliary guide is rotated by the rotation guide portion to narrow and widen the gap forming the recording medium conveyance path; Configured to rotate,
When conveying the recording medium toward the shift roller pair and the gate means by pressing the feed roller pair in a state where the gate member is displaced to the protruding position and the shift roller pair is separated, The auxiliary guide is rotated to a position that narrows the gap that forms the recording medium conveyance path by the rotation guide portion, and after the leading end of the recording medium abuts against the gate member, the recording medium is moved by the feed roller pair. When the buffer is formed on the recording medium between the gate member and the feed roller pair by over-conveying, a position where the auxiliary guide is widened by the rotation guide portion to form the recording medium conveyance path A printing apparatus, characterized in that a rotating means is provided.   The means for rotating the auxiliary guide by the rotation guide portion is fixed to a cam shaft that is common to a cam that controls the contact / separation operation of the feed roller pair and a cam that controls the displacement operation of the gate member, A cam for controlling the contact / separation operation of the shift roller pair, and the cam surface of the cam is always in contact with the cam, and the feed roller pair is brought into and out of contact with the cam. The printing apparatus according to claim 1, wherein the printing apparatus is a lever having a driving piece.   The means for rotating the auxiliary guide by the rotation guide portion extends in a direction to widen a gap that forms a recording medium conveyance path between the rotation guide portion and the lower recording medium conveyance guide on the shift roller opposite side. 2. The rotary guide according to claim 1, wherein the auxiliary guide is rotated to a position where a gap for forming a recording medium conveyance path is widened between the auxiliary guide and the lower recording medium conveyance guide on the opposite side of the feed roller. The printing apparatus according to 2.   The means for rotating the auxiliary guide by the rotation guide unit rotates the auxiliary guide to a plurality of positions as positions for widening a gap forming the recording medium conveyance path. The printing apparatus according to claim 1.   3. The printing apparatus according to claim 2, wherein the means for rotating the auxiliary guide by the rotation guide portion has a cam surface of a cam that controls the contact / separation operation of the shift roller pair in a plurality of stages. A printing apparatus, wherein the auxiliary guide is rotated to a plurality of positions as a position to widen a gap forming the recording medium conveyance path according to a rotation angle of the cam.   6. The printing apparatus according to claim 4, wherein a plurality of positions are selected by which the auxiliary guide widens a gap forming the recording medium conveyance path according to the rigidity of the recording medium used for printing. Printing device to do. A recording medium alignment mechanism provided in the recording medium conveyance path when the recording medium fed out from the recording medium storage unit one by one is conveyed to the printing unit via the recording medium conveyance path to print an image on the recording medium. The recording medium transporting mechanism corrects the posture of the recording medium conveyed by the recording medium, and the recording medium aligning mechanism includes a drive roller that can be contacted and separated from each other at a predetermined interval on the downstream side and the upstream side in the recording medium medium conveying direction. A blocking roller position and a driven roller pair, and a blocking position that is inserted into a recording medium transport path downstream of the shift roller pair in the recording medium transport direction to block the passage of the recording medium; A shift member configured to form a recording medium conveyance path of the recording medium alignment mechanism unit, the gate member being displaceable to a retraction position that is retracted from the recording medium conveyance path to allow the recording medium to pass therethrough. The recording medium conveyance guide on the opposite side of the roller and the recording medium conveyance guide on the opposite side of the feed roller are provided separately, and a part of the upper recording medium conveyance guide on the opposite side of the feed roller on the downstream side in the recording medium conveyance direction is provided. And an auxiliary guide that can be rotated to a position that widens and narrows a gap that forms a recording medium conveyance path with the lower recording medium conveyance guide, and
A part of the upper recording medium conveyance guide on the opposite side of the shift roller on the upstream side in the recording medium conveyance direction is configured as a rotatable rotation guide part, and the end of the rotation guide part on the upstream side in the recording medium conveyance direction is formed. A recording medium alignment mechanism control method in a printing apparatus in contact with the lower surface of the free end of the auxiliary guide on the downstream side in the recording medium conveyance direction,
Rotating the rotation guide portion in a separated state of the shift roller pair;
When the recording medium is conveyed toward the shift roller pair and the gate means by pressing the feed roller pair in a state where the gate member is displaced to the blocking position and the shift roller pair is separated, The auxiliary guide is rotated by a rotation guide portion to a position that narrows a gap forming the recording medium conveyance path,
After the leading end of the recording medium is abutted against the gate member, the recording medium is over-conveyed by the feed roller pair to form a buffer on the recording medium between the gate member and the feed roller pair. A method for controlling a recording medium alignment mechanism in a printing apparatus, wherein the rotation guide unit rotates the auxiliary guide to a position where a gap forming the recording medium conveyance path is widened.   Three cams fixed to a common cam shaft each make contact / separation operation of the shift roller pair, displacement operation of the gate member, contact / separation operation of the feed roller pair, and rotation of the rotation guide portion. 9. The method of controlling a recording medium alignment mechanism in a printing apparatus according to claim 8, wherein the rotation of the auxiliary guide by movement is controlled in conjunction with each other.

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