JP2013230890A - Sheet conveying apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying apparatus and an image forming apparatus configured to improve workability and visibility during jamming processing, and to improve image printing performance against a skew, lateral registration or the like.SOLUTION: A sheet conveying apparatus includes: an upper roller support unit 148 arranged on an upper conveyance guide plate 128; and a lower roller support unit 149 arranged on a lower conveyance guide plate 129. In a state that a lower conveyance guide plate 129 is made to come close to the upper conveyance guide plate 128 by bringing a driven roller 117b in press contact with a driving roller 117a to form a conveyance nip therebetween, connection mechanisms (133, 155, 134, 139, 140) connect both the roller support units, and also connect both the conveyance guide plates so that the roller support units 148 and 149 function as sliding units 152 as a whole which are movable relative to the conveyance guide plates 128 and 129.

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and an image forming apparatus such as a copying machine, a facsimile, and a printer including the sheet conveying apparatus.

  In an image forming apparatus such as a copying machine, a facsimile machine, or a printer, the print position of a printed image may be shifted from the sheet. This is because, for example, the sheet is shifted in the width direction (hereinafter also referred to as “horizontal registration”) perpendicular to the sheet conveyance direction with respect to the image in the paper feed cassette, or is positioned obliquely (hereinafter also referred to as “skew”). One of the factors is that it is. Further, the lateral registration or skew may occur in the transport path after feeding.

  Thus, as a configuration for improving the image printing accuracy, skew feeding correction by sheet edge butting and lateral registration correction by registration roller shift are known. For example, a conveyance device having a skew correction mechanism that corrects skew by abutting the leading end of a sheet against a registration roller is known (see Patent Document 1).

  In this transport apparatus, first, the leading side of the leading edge of the sheet transported from the registration upstream roller (hereinafter referred to as “pre-registration roller”) hits the nip edge of the registration roller that is stopped. Further, the sheet is excessively pushed by the pre-registration roller, thereby forming a loop with the registration roller. As a result, when the sheet is swung in the loop, the contact gradually shifts to the delay side, and finally, the entire area of the front end of the sheet follows the ridge line of the nip portion of the registration roller, thereby correcting the skew. Thereafter, the registration roller is driven and conveyed to the image forming unit.

  Also, an image forming apparatus having a configuration for performing lateral registration correction by registration roller shift is known (see Patent Document 2). This image forming apparatus includes a lateral registration detection sensor that detects a side edge of the sheet and a mechanism that moves the registration roller in the thrust direction. Then, with the sheet held between the registration rollers, the lateral registration is corrected by thrust-moving the sheet end portion to an appropriate position based on the detection of the lateral registration detection sensor.

  However, in the lateral registration correction mechanism using such a registration roller shift, the sheet is shifted while being nipped (clamped) between the pre-registration roller and the registration roller. It was happening. In other words, the reaction force caused by the twisting of the loop between the two causes inconveniences such as skewing and wrinkling when the sheet is conveyed by the registration roller. In particular, when the sheet is thick paper with high rigidity, the skew becomes noticeable because the reaction force due to loop twist is large.

  Thus, a sheet aligning device configured to eliminate the loop twist has been proposed (see Patent Document 3). This sheet aligning apparatus has a configuration (hereinafter referred to as “slide configuration”) in which the pre-registration roller is thrust-free supported by a linear bearing member. Thereby, in the sheet aligning device, when the registration roller is shifted in a state where the sheet is sandwiched, the pre-registration roller is also thrust-moved through the sheet to eliminate the loop twist. Since compression springs are arranged at both ends of the pre-registration roller to urge the roller to the center, the pre-registration roller automatically returns to the center position after the trailing edge of the sheet is removed.

  The configuration of the sheet aligning apparatus is not limited to the pre-registration roller, and is effective for eliminating loop twisting for a large-sized sheet by being applied to a further upstream conveying roller. Specifically, in the sheet aligning apparatus 10 shown in FIG. 19, a registration roller 11 that shifts in a sheet conveyance path 161 from the sheet feeding apparatus, and a pre-registration roller 12 that is disposed so as to be capable of thrust movement. A slide roller is arranged. As a result, a configuration effective for eliminating the loop twist with respect to the large-size sheet described above is obtained.

  In the sheet aligning device 10, a sensor Sr that restricts the movement position of the drive shaft 11 a is disposed at the other end of the drive shaft 11 a of the registration roller 11. When the sheets are aligned, the registration roller 11 is moved in the horizontal direction by the horizontal movement mechanism 15 with the leading edge of the sheet S being held. When the trailing edge of the sheet S finishes passing while the side Pe of the sheet S is aligned with the reference line K, the registration roller 11 is returned to the position set based on the sensor Sr. And wait. Reference numeral 3 in the figure denotes a gate member that is disposed immediately before the registration roller 11 and can be moved in and out of the sheet conveyance path, Sp is a sheet sensor, 30 and 30a are lateral movement regulating members such as compression springs, 16 Is a rack, 17 is a drive gear, and 18 is a driven gear.

Japanese Patent No. 4016621 Japanese Patent No. 2893540 Japanese Patent No. 3191834

  Incidentally, in the conventional sheet aligning apparatus 10, a load is generated when the pre-registration roller 12 slides due to the reaction force of the urging force for forming the conveyance nip. For this reason, the pre-registration roller 12 cannot slide smoothly, and there is a possibility that the positional accuracy of the sheet related to skew feeding / horizontal registration or the like may be lowered.

  In order to cope with the above problem, there is the following problem when a pair of guide members individually supporting the rollers of the conveying roller pair such as the pre-registration roller 12 are integrated. That is, when a sheet jam occurs in the sheet conveyance path having the slide configuration, the sheet conveyance path cannot be opened. For this reason, the user or operator must grasp the upstream or downstream sheet end of the conveying roller pair and pull out the sheet nipped by the conveying roller pair. For this reason, there has been a problem that workability and visibility are inferior compared with a case where a pair of guide members are opened to perform jam processing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveying apparatus and an image forming apparatus that improve workability and visibility during jam processing while improving the conveyance accuracy.

  The present invention includes a first conveyance guide plate supported by an apparatus main body, a second conveyance guide plate supported so as to be openable and closable with respect to the first conveyance guide plate, and a first roller. A first roller support unit disposed on the guide plate, and a second roller support unit disposed on the second conveyance guide plate, the second roller support unit including a first roller support unit disposed on the guide plate and a second roller biased by a biasing member toward the first roller. And when the second conveyance guide plate is opened with respect to the first conveyance guide plate, the second roller is separated from the first roller. A sheet conveying apparatus in which a two-roller supporting unit is separated, wherein the first and second roller supporting units can be moved integrally with respect to the first and second conveying guide plates in a width direction perpendicular to the sheet conveying direction. Supporting slide mechanism and The first and second roller support units are in a state where the second conveyance guide plate is brought close to the first conveyance guide plate so as to form a conveyance nip by pressing the second roller against the first roller. A connection that connects the first and second roller support units and connects the first and second transport guide plates so as to be a slide unit that is movable relative to the first and second transport guide plates. And a mechanism.

  According to the present invention, while improving workability at the time of jam processing, the roller pair is formed while supporting only the weight of the slide unit by the slide mechanism without applying the biasing force for forming the conveyance nip to the slide mechanism. It can slide in the width direction. Thereby, it is possible to improve the workability and visibility at the time of jam processing while reducing the load at the time of slide movement and improving the positional accuracy of the sheet with respect to skew and lateral registration.

1 is a schematic sectional view of a color digital printer as an image forming apparatus according to the present invention. FIG. 3 is a perspective view of a sheet skew correction device including a registration unit according to the embodiment. (A)-(d) is the top view and side view which looked at the skew feeding correction | amendment operation | movement of a sheet | seat and the lateral registration correction | amendment operation from the conveyance path upper side and the side surface. The flowchart for demonstrating the operation | movement in embodiment. The block diagram which shows the control system in embodiment. The top view which shows a loop shape when a registration roller pair is shifted in the state which pinched | interposed the sheet | seat. (A)-(c) is a figure which shows the state in which the roller pair before registration forms the conveyance nip. (A)-(c) is a figure which shows the state in which the roller pair before registration has canceled the conveyance nip. Sectional drawing shown about schematic structure from a feeding deck to a registration part. (A) is a perspective view showing a slide configuration, (b) is a perspective view showing an extracted slide unit, (c) is a perspective view showing an upper roller support unit, and (d) is a lower roller support unit. FIG. (A) is a front view of a slide unit, (b) is a front view in which a portion connecting an upper roller support unit and a lower roller support unit and a forming portion of a conveyance nip are visualized. (C) is a front view which shows only an upper roller support unit provided with the upper conveyance guide plate. (A) is a diagram showing a state in which the slide unit is in a nominal position, (b) is a diagram showing a state in which the slide unit is slid to the near side, and (c) is a state in which the slide unit is slid to the back side. FIG. (A)-(c) is a top view of a slide center positioning part, respectively. (A) is a perspective view showing the slide unit in an opened state, (b) is a front view showing the upstream direction from the downstream side of the conveyance path, and (c) is a view of the opened slide unit from the left side. The figure shown in the state. (A)-(d) is a perspective view which shows a 2nd hook member etc., respectively, a left view, a front view, and a bottom view. (A) is a diagram when the drive roller is held at the nominal center position, (b) is a diagram when the drive roller is shifted to the near side, and (c) is a diagram where the drive roller is shifted to the back side. Figure when. (D) is a view when the slide drive unit is viewed from the back side, and (e) is a view when the slide drive unit is viewed from an oblique front side. The figure which summarized the structure which concerns on the slide unit in a sheet conveying apparatus roughly. Schematic which shows a comparative example. The top view which shows the conventional sheet aligning apparatus.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a color digital printer as an image forming apparatus according to the present invention.

<First Embodiment>
[Configuration of Entire Image Forming Apparatus]
As shown in FIG. 1, the image forming apparatus 100 includes an apparatus main body 97 and a feeding deck 150 connected to the apparatus main body 97 via a feeding buffer device 118. In the apparatus main body 97, there is provided a control unit 50 that comprehensively controls each part of the apparatus.

  In the image forming apparatus 100, the four photosensitive drums 101a to 101d provided in the image forming unit 96 that forms an image on the conveyed sheet are charged with uniform charges on the surfaces by the charging rollers 102a to 102d, respectively. . Image signals of yellow (Y), magenta (M), cyan (C), and black (K) are input to the laser scanners 103a to 103d provided in the image forming unit 96, respectively, and drums are generated according to the image signals. The surface is irradiated with laser light, the charge is neutralized, and a latent image is formed.

  The latent images formed on the photosensitive drums 101a to 101d are developed with yellow, magenta, cyan, and black toners by the developing devices 104a to 104d, respectively. The toner developed on each of the photosensitive drums 101a to 101d is sequentially transferred to the intermediate transfer belt 106, which is an endless belt-like image carrier, by the primary transfer rollers 105a to 105d, and the full color is transferred onto the intermediate transfer belt 106. A toner image is formed.

  On the other hand, the sheet S, which is a transfer material such as recording paper fed from one of the paper feed cassettes 111 and 112, is directed to the registration roller pair 120 via the conveyance roller pair 114 and the pre-registration roller pair 115. Are transported. Further, the sheet S fed from the feeding deck 150 is directed toward the registration roller pair 120 via the feeding buffer roller pair 117 including the driving roller 117a and the driven roller 117b and the pre-registration roller pair 115. Be transported.

  The registration unit 116 includes the registration roller pair 120, the pre-registration roller pair 115, the CIS (Contact Image Sensor) 143, the registration sensor 160, and the skew detection sensors 141F and 141R.

  The registration roller pair 120 controls the toner image on the intermediate transfer belt 106 so that there is no misalignment between the sheet S and the image. The toner image is transferred from the intermediate transfer belt 106 to the sheet S via the secondary transfer unit 99 and then heated and pressed by the fixing device 110 to be fixed. Thereafter, the sheet S is discharged from the discharge unit 119a or 119b to the stacking unit 98 on the upper part of the apparatus main body 97. The secondary transfer unit 99 includes a secondary transfer outer roller 109a and a secondary transfer inner roller 109b that are opposed to each other with the intermediate transfer belt 106 interposed therebetween.

  A side regulating plate (not shown) that regulates the position of the sheet S in the width direction orthogonal to the sheet conveying direction is movable in the sheet feeding cassettes 111 and 112 and the feeding deck 150 according to the side edge of the sheet S. Has been placed. Thereby, the position in the width direction of the sheet S (hereinafter referred to as “lateral registration position”) can be aligned with the image forming unit.

  In the paper feed cassettes 111 and 112, a pair of separation rollers including a feed roller 93 that feeds the stored sheet S, a feed roller 94 that separates and feeds the fed sheet S and a retard roller 95, and the like. And are arranged. The feeding deck 150 is provided with a pickup roller 126 for the stored sheet S and a deck pulling roller 125 (see FIG. 9) for separating and feeding the fed sheet S into only one sheet. . Further, the feeding deck 150 is provided with a deck feeding roller 124 (see also FIG. 9) for feeding the sheet S fed from the deck drawing roller 125 to the feeding buffer device 118.

  Drive rotation of the pickup roller 126 is transmitted to the deck drawing roller 125 via the endless belt 75. In FIG. 1, for convenience, the endless belt 75, the deck pulling roller 125, and the like are not illustrated, but actually have the configuration shown in FIG.

  In addition, the side regulating plate also has an effect of preventing the skew that occurs when the sheet is fed and the skew that is caused by the conveyance rollers on the downstream side such as the feeding roller 93. However, in reality, a slight shift between the side regulating plate and the sheet may cause a lateral registration shift and skew, and a lateral registration amount (hereinafter referred to as “input lateral registration amount”) when inputting to the registration roller pair 120. ) And the amount of skew (hereinafter “input skew amount”) may vary.

  Therefore, the skew can be corrected by causing the leading end of the sheet to contact the stopped pair of registration rollers 120 and further forming a loop with the pair of pre-registration rollers 115 upstream thereof. The loop amount at this time is adjusted by performing a predetermined amount of excessive feeding after passing through the registration sensor 160 that detects the leading edge of the sheet. A CIS 143 for detecting a lateral registration position of the sheet S is disposed between the registration roller pair 120 and the secondary transfer unit 99.

  After the conveyance by the registration roller pair 120 is started, the control unit 50 calculates a deviation amount between the detection result by the CIS 143 and the nominal position as a lateral registration correction amount. Then, the lateral registration position of the sheet is corrected by shifting the registration roller pair 120 in the thrust direction by the lateral registration shift amount.

[Configuration of Registration Unit 116]
Next, the configuration of the registration unit, the skew feeding correction operation, and the lateral registration correction operation will be described with reference to FIG. FIG. 2 is a perspective view of the sheet skew correction device including the registration unit 116 according to the present embodiment. However, for simplicity, only the lower side of the sheet conveyance guide is shown, and the upper side is not shown.

  As shown in FIG. 2, the pre-registration roller pair 115 is configured such that a pre-registration upper roller 115a having a roller made of polyacetal (POM) and a pre-registration lower roller 115b formed by a rubber roller are arranged to face each other. Is done. A pressure spring 113 is hung on each of the bearing portions provided in the plurality of pre-registration upper rollers 115a. As a result, the pre-registration upper roller 115a is pressed against the pre-registration lower roller 115b to form a conveyance nip. The sheet S is conveyed using a pre-registration drive motor (hereinafter referred to as “drive motor”) 121 shown in FIGS.

  Similarly, as shown in FIG. 2, the registration roller pair 120 is configured such that a registration upper roller 120a having a roller made of POM and a registration lower roller 120b formed of a rubber roller are arranged to face each other. The pressure springs 13 are respectively hung on the bearing portions provided in the registration upper roller 120a. As a result, the upper registration roller 120a is pressed against the lower registration roller 120b to form a conveyance nip.

  As described above, the registration roller pair 120 is responsible for skew correction and lateral registration correction of the sheet S, and it is necessary to accurately convey the sheet to the image forming unit 96. Therefore, the clamping pressure of the registration roller pair 120 is often set higher than other rollers (for example, about 2.5 kgf to 5.0 kgf). The sheet S is conveyed using a drive motor 61 such as a stepping motor as a drive source.

  Here, the mechanism for shifting the sheet S in the thrust direction (left-right direction in FIG. 2) is configured as follows. That is, when the registration roller shift motor (registration roller shift motor) 42 that shifts the registration roller pair 120 in the thrust direction is driven, the pinion gear 44 fixed to the rotation shaft rotates. As a result, the rack 45 meshing with the pinion gear 44 moves in translation.

  The rack 45 is supported with respect to the rotation shaft 120c of the registration roller pair 120 so that the rack 45 is free in the rotational direction and positioned in the thrust direction. Thereby, the relative position of the rack 45 and the rotating shaft 120c does not change in the thrust direction.

  With the above configuration, the thrust movement operation of the registration roller pair 120 is enabled, and the sheet S sandwiched between the registration roller pair 120 can be shifted in the width direction (left and right direction in FIG. 2) perpendicular to the sheet conveyance direction. it can.

  An input gear 63 is fixed to one end of the rotating shaft 120d of the registration lower roller 120b. In the vicinity of the input gear 63, a drive motor 61 that rotates the rotation shaft 120d to rotate the registration roller pair 120 is disposed. A motor gear 62 that meshes with the input gear 63 of the rotary shaft 120 d and transmits the rotation of the drive motor 61 to the input gear 63 is fixed to the rotary shaft of the drive motor 61.

  The input gear 63 has a wider tooth width than the motor gear 62. This is because, even when the registration roller pair 120 and the input gear 63 are thrust, the meshing of the gears is maintained well and the registration roller pair 120 can be rotated.

  The input lateral registration amount is detected by the CIS 143. The CIS 143 is disposed in front of the secondary transfer unit 99 in the sheet conveyance direction, and is deviated from the center in the width direction orthogonal to the sheet conveyance direction. This is because it is sufficient to detect the side edge of one side of the sheet S from the minimum width to the maximum width.

[Declination correction operation and horizontal registration correction operation]
Next, the basic skew correction operation and lateral registration correction operation of the sheet in the registration unit 116 will be described with reference to FIGS. 3A to 3D respectively show the skew feeding correction operation and the lateral registration correction operation of the sheet S conveyed to the registration roller pair 120 by the pre-registration roller pair 115 from the upper side and the side surface of the conveyance path. It is the top view and side view which were seen from. FIG. 4 is a flowchart for explaining these operations, and FIG. 5 is a block diagram showing a control system in the present embodiment.

  As shown in FIG. 5, the control unit 50 provided in the apparatus main body 97 includes an operation unit 200 (not shown in FIG. 1) provided in the apparatus main body 97 and a registration drive motor (registration motor) 61. It is connected. A registration roller shift motor (hereinafter referred to as “shift motor”) 42 as a registration roller shift motor, a feeding motor 54, and a registration sensor (registration sensor) 160 are connected to the control unit 50. Further, the skew detection sensors 141F and 141R and the CIS (lateral registration detection sensor) 143 are connected to the controller 50, and a computer such as a personal computer connected to the image forming apparatus 100 directly or via a network. 201 is connected.

  When the processing is started, the control unit 50 starts executing a print job input from the operation unit 200 or the computer 201 (Step 101 in FIG. 4). When the feeding operation of the sheet S by the feeding roller 93 or the feeding roller 90 is started (Step 102), the sheet passes through the conveying roller pair 114 or the feeding buffer roller pair 117 of the feeding buffer device 118. Then, it is conveyed to the registration unit 116.

  At this time, for example, when the sheet S is conveyed in the direction of the arrow A in FIG. 3A while being skewed in the direction in which the back side of the apparatus (the back side of the paper in FIG. 1) has advanced, FIG. 1 and FIG. Input skew is calculated by the skew detection sensors 141F and 141R shown (Step 103).

  When the conveyance is further continued, the leading edge on the right side of the sheet S in the conveyance direction comes into contact with the roller member 120e on the back side of the registration upper roller 120a. At this time, the static torque of the registration roller drive motor (hereinafter referred to as “drive motor”) 61 is larger than the abutting force due to the stiffness (rigidity) of the sheet S. Therefore, the registration roller pair 120 remains stopped, and the sheet S is prevented from advancing by the registration upper roller 120a.

  At this time, since the sheet S is skewed, the roller member 120e on the front side of the registration roller pair 120 (on the front side in FIG. 1) does not come into contact with the sheet S. By continuing further conveyance by the pre-registration roller pair 115, a loop Lo is formed as shown in FIG. 3B, and the roller S 120e on the front side of the apparatus that has not been in contact with the sheet S is also formed on the sheet S. Are brought into contact with each other (Step 104).

  That is, at the position of the pre-registration roller pair 115, the skew correction is performed by aligning the leading edge of the skewed sheet S with the conveyance nip of the registration roller pair 120. For this reason, in the sheet S, the loop Lo is twisted at this time.

  Thereafter, the control unit 50 drives the drive motor 61 to start the rotation of the registration roller pair 120. Then, the control unit 50 conveys the sheet S to the downstream side by the rotation of the registration roller pair 120 while maintaining the state in which the skew is corrected (FIG. 3C), and the sheet side end portion is moved by the CIS 143. The input lateral registration amount is detected (Step 105).

  The difference between the detection result and the nominal value is the lateral registration shift correction amount to be corrected, and the control unit 50 drives the shift motor 42 to shift the registration roller pair 120 in the thrust direction to correct the lateral registration of the sheet. (Step 106). At this time, the lateral registration position is different between the pre-registration roller pair 115 and the registration roller pair 120, and the loop Lo is twisted (FIG. 3D).

  Thereafter, the sheet S is conveyed by the registration roller pair 120 (Step 107), sent to the secondary transfer unit 99 to transfer the image onto the sheet S, and then discharged from the discharge unit 119a or 119b to the stacking unit 98. Is executed (Step 108). Then, after the series of print jobs is completed (Step 109), the registration roller pair 120 is returned to the home position (HP) before the thrust movement (Step 110).

[Explanation of Loop Caused by Skew Correction and Horizontal Registration Correction]
Next, a loop caused by horizontal registration correction and skew correction will be described with reference to FIG. FIG. 6 is a plan view showing a loop shape when the registration roller pair 120 is shifted in the direction of the arrow B in a state where the sheet S is sandwiched between the registration roller pair 120 and the pre-registration roller pair 115.

  Here, the movement from the near side to the far side of the apparatus main body 97 is defined as a plus shift, and the movement from the far side to the near side is defined as a minus shift. FIG. 6 shows a state when the registration roller pair 120 is moved in the direction of arrow B and shifted positively.

  At this time, as a feature of the loop shape, the loop height (size) LoF on the front side (near side in FIG. 1) and the loop size LoR on the back side (back side in FIG. 1) are equal. Is mentioned. Furthermore, it can be mentioned that the ridgelines e1d and e1u serving as the bending deflection points are parallel to each other and have an angle α with respect to the sheet leading edge. As a result, it is known that the sheet S generates a force that turns in the direction of arrow D in FIG. 6 at the portion sandwiched between the registration roller pair 120.

  Actually, a loop is rarely formed in such an open space, and is usually surrounded by the conveyance guide space, and the sheet S may come into contact with the conveyance guide due to the deformation of the loop. In this case, the turning force in the direction of arrow D is further increased. When the turning force exceeds the clamping force of the registration roller pair 120, skew may become more noticeable in the registration roller pair 120.

  As described above, the registration roller pair 120 is generally set to have a higher pinching pressure than the other transport rollers so as not to cause a transport slip in order to accurately adjust the leading edge timing with the image. However, if a large turning force is generated, slipping may occur.

[Configuration of Pre-Registration Roller Pair 115]
As described above, the twisting force caused by the skew correction and the lateral registration correction by the registration roller pair 120 may cause a turning force and cause a slip. Therefore, in the present embodiment, a configuration is employed in which the conveyance nip of the pre-registration roller pair 115 is opened when the lateral registration correction by the registration roller pair 120 is performed.

  7 and FIG. 8, the direction from the registration roller pair 120 to the pre-registration roller pair 115 is the front, (a) left side view, (b) front view. It shows as a figure and (c) right view. 7A to 7C show a state in which the pre-registration roller pair 115 forms a conveyance nip, and FIGS. 8A to 8C show the pre-registration roller pair 115 to be conveyed. The state where the nip is released is shown.

  That is, in the state shown in FIG. 8, the pre-registration roller pair 115 is rotationally driven by the drive motor 121 driven under the control of the control unit 50. During this drive, the pre-registration upper roller 115a is rotated along with the pre-registration lower roller 115b that is driven to rotate (driven rotation).

  The pre-registration upper roller 115a is urged in a direction approaching the pre-registration lower roller 115b by the pressure spring 113 described in FIG.

  Here, when the eccentric cam gear 123 is rotated and held at the position shown in FIG. 7 by driving the pre-registration separation motor 122, the gap between the axes of the pre-registration roller pair 115 becomes narrow La, and the pre-registration roller pair 115 A conveyance nip is formed. On the other hand, when the eccentric cam gear 123 is rotated and held at the position shown in FIG. 8 by driving the pre-registration separation motor 122, the distance between the axes of the pair of pre-registration rollers 115 becomes Lb (> La). The conveyance nip of the front roller pair 115 is released.

  With the configuration described above, by switching the axis between the pre-registration roller pair 115 between narrow La and wide Lb, it is possible to avoid slipping due to the turning force of loop torsion and prevent skew from becoming noticeable. it can.

[Description of upstream transport roller configuration]
Next, the configuration of the slide unit 152 having the feed buffer roller pair 117 that is the upstream transport roller, which is a feature of the present invention, will be described. FIG. 9 is a cross-sectional view illustrating a schematic configuration from the feeding deck 150 to the registration unit 116.

  As shown in FIG. 9, a feeding deck 150 connected to the apparatus main body 97 via a feeding buffer device 118 can stack more sheets S than the sheet feeding cassettes 111 and 112 in the apparatus main body 97. It is configured. Due to the characteristics of the conveyance path, the feeding deck 150 can feed and convey types of sheets that are difficult to feed and convey (for example, highly rigid sheets or sheets having a large basis weight) from the sheet feeding cassettes 111 and 112. Composed. The feeding deck 150 is configured not to be a feeding deck dedicated to a certain image forming apparatus but also to an image forming apparatus having various specifications.

  In the image forming apparatus 100 that requires high-precision printing accuracy, skew correction and lateral registration correction by registration roller shift for improving printing accuracy are as described above. However, a long sheet may be conveyed in the sheet conveying direction, such as A3 size. Therefore, a feed buffer device 118 having a slide unit 152 including a feed buffer roller pair 117 is interposed between the feed deck 150 and the apparatus main body 97 for good registration roller shift. The slide unit 152 is pulled by the sheet so as to follow the turning force generated by the loop twist of the nipped sheet in a state where the entire weight is supported by the slide mechanism including the linear bearing 151 and the slide table 159. Move in the width direction perpendicular to the transport direction.

  The feed buffer roller pair 117 of the feed buffer device 118 has a slide configuration that slides in the shift direction of the registration roller pair 120 (pre-registration roller pair 115). This slide configuration follows the turning force generated by the loop twist caused by the shift of the registration roller pair 120 and the pre-registration roller pair 115.

  In the present embodiment, the feeding buffer device 118 having this slide configuration prevents the problem of skewing due to loop twisting. To achieve this, when feeding a long sheet in the transport direction, the sheet is fed in such a direction that the loop twist generated between the registration roller pair 120, the pre-registration roller pair 115, and the feed buffer roller pair 117 is eliminated. The buffer roller pair 117 is slid.

  Since the feeding buffer device 118 is a connecting portion between the apparatus main body 97 and the feeding deck 150, a feeding buffer roller is generated when a jam occurs in which the sheet S stays in the feeding buffer apparatus 118 and the apparatus main body 97. The conveyance nip and conveyance path of the pair 117 are configured to be openable. With this configuration, accessibility and visibility are improved for an operator who performs jam processing.

[Conveyance path opening configuration and slide configuration]
The conveyance path opening configuration and the slide configuration of the sheet conveyance device described here are not limited to the feeding buffer device 118, but the conveyance roller pair 114 arranged on the conveyance path from the sheet feeding cassette 111 or 112. It can also be applied to parts and the like.

  Hereinafter, the conveyance path opening configuration and the slide configuration will be described with reference to FIGS. Although it has been described above that the configuration of the sheet conveying apparatus according to the present invention is not limited to the feeding buffer device 118, a case where the present configuration is applied to the feeding buffer device 118 will be described below.

  Hereinafter, an example in which the sheet conveying device according to the present invention is applied to a feeding buffer device 118 having a slide unit 152 including a feeding buffer roller pair 117 will be described. 10A is a perspective view illustrating a slide configuration including the slide unit 152, and FIG. 10B is a perspective view illustrating the slide unit 152 extracted. FIG. 10C is a perspective view showing the upper roller support unit 148 that holds the driving roller 117a that rotates by receiving the driving force. FIG. 10D is a perspective view showing an extracted lower roller support unit 149 that holds a driven roller 117b that rotates in contact with the drive roller 117a. The upper roller support unit 148 constitutes the first roller support unit of the present invention. Further, the lower roller support unit 149 constitutes a second roller support unit of the present invention that is movable with respect to the upper roller support unit (first roller support unit) 148.

  FIG. 11A is a front view showing a state in which the slide unit 152 is viewed from the downstream side of the conveyance path to the upstream side. FIG. 11B is a front view in which a portion connecting the upper roller support unit 148 and the lower roller support unit 149 and a forming portion of the conveyance nip are visualized in FIG.

  First, the upper roller support unit 148 will be described. As shown in FIG. 10C, in the upper roller support unit 148, the drive roller 117a is rotatably attached to the slide upper guide 132 via a bearing 147. Further, a feed buffer input gear 131 is attached to one end (the right end in the figure) of the rotating shaft 117c of the drive roller 117a. The bearing 147 is also provided at one end (the right end in the figure) of the driving roller 117a. The drive roller 117a and the upper slide guide 132 that holds the drive roller 117a constitute an upper roller support unit 148.

  The upper roller support unit 148 has a driving roller (first roller) 117a that is supported so as to be movable in the width direction via a linear bearing 151 and a slide base 159 in a direction in which the loop of the conveyed sheet is not twisted. Arranged on the upper conveyance guide plate 128. The linear bearing 151 and the slide base 159 constitute the slide mechanism of the present invention. Further, the upper transport guide plate 128 constitutes the first transport guide plate of the present invention.

  As shown in FIGS. 10A to 10C, a slide cam member 137 having a smooth slope is provided in the longitudinal direction of the slide upper guide 132 at the front center portion of the slide upper guide 132 of the upper roller support unit 148. It is fixed along The slide cam member 137 is for urging the slide unit 152 to a designated position, and details will be described later.

  Note that the upper conveyance guide plate 128 and the lower conveyance guide plate 129 shown in FIGS. 10 (a) and 14 (a) actually protrude slightly toward the deck feed roller 124 upstream of the conveyance as shown in FIG. It is formed to do. Moreover, the upper side conveyance guide plate 128 and the lower side conveyance guide plate 129 in FIG. 1 are drawn more flat than an actual shape for convenience. The lower conveyance guide plate 129 constitutes the second conveyance guide plate of the present invention.

  The feed buffer input gear 131 is rotationally driven via an idler gear 136 (FIG. 10A) that rotates by receiving a driving force from the feed buffer drive motor 127. The feed buffer drive motor 127 is disposed in the main body (118a) of the feed buffer device 118 (see FIG. 17).

  The idler gear 136 is rotatably attached to a position that meshes with the feed buffer input gear 131 at one end (the right end in the figure) of the upper transport guide plate 128 supported by the apparatus main body (118a) (FIG. 14A). reference). A toothed pulley 72 (see FIG. 14A) is attached to the rotating shaft 127a of the feed buffer drive motor 127, and between the toothed pulley 72 and the toothed pulley (not shown) at the end of the idler gear 136, An endless timing belt 73 (FIG. 14A) is wound around.

  The idler gear 136 is formed so as to increase in width in the front-back direction (left-right direction in FIG. 10), and even when the driving roller 117a slides in the front-back direction, the engagement with the idler gear 136 is reliably maintained. It is comprised so that.

  As shown in FIGS. 11A and 11B, the driving roller 117a, which is the first roller, is rotatably supported by a rotating shaft 117c supported by the upper roller support unit 148 at a predetermined distance. ing. Further, two driven rollers 117b, which are second rollers, are rotatably supported at a predetermined distance on a rotating shaft 117d supported by a lower roller support unit 149 via a holder 146. In the present embodiment, the first roller of the present invention is the driving roller 117a and the second roller of the present invention is the driven roller 117b, but this relationship can be reversed. That is, the first roller of the present invention can be the driven roller 117b, and the second roller of the present invention can be the drive roller 117a.

  Second hook pins 140 for connecting and coupling the lower roller support unit 149 are attached to both ends of the slide upper guide 132 of the upper roller support unit 148. Further, as shown in FIG. 10A, connecting pins 88 are attached to both ends of the upper conveyance guide plate 128 (see also FIG. 14A). The connecting pin 88 rotatably connects support members 87 attached to both ends of the lower conveyance guide plate 129 so that the lower roller support unit 149 can be opened and closed with respect to the upper roller support unit 148.

  That is, the lower conveyance guide plate 129 is formed in the width direction (the left-right direction in FIG. 14A) perpendicular to the sheet conveyance direction (front-back direction in FIG. 14B, left-right direction in FIG. 14C). ) (Supporting pin 88) as a fulcrum and is supported by the upper conveyance guide plate 128 so as to be openable and closable.

  Next, the lower roller support unit 149 will be described. As shown in FIG. 10D, the lower roller support unit 149 is configured by the driven roller 117b and the slide lower guide 135 that holds the driven roller 117b. The lower roller support unit 149 has a driven roller 117b urged by a roller pressure spring (biasing member) 156 so as to be directed to the driving roller 117a, and is disposed on the lower conveyance guide plate 129. The roller pressing spring 156 also constitutes a spring member that presses the driving roller 117a that is the first roller and the driven roller 117b that is the second roller.

  The driven roller 117b is rotatably attached to the holder 146 via a bearing 145 as shown in FIG. The holder 146 is attached to the slide lower guide 135 so as to be movable together with the slide lower guide 135 in the vertical direction of FIG. The holder 146 is urged in the direction of arrow F by a roller pressing spring 156 while attached to the slide lower guide 135.

  The roller pressurizing spring 156 is composed of, for example, a coil spring or a leaf spring, and both ends thereof are attached to and supported by a support portion 149a in the lower roller support unit 149 as shown in FIG. . In this state, the holder 146 is urged so that the driven roller 117b protrudes outward from the lower roller support unit 149.

  As shown in FIGS. 11A and 11B, hook shafts 142 are attached to both ends of the lower slide guide 135, and the second hook members 139 rotate on the hook shafts 142 on both ends. It is attached as possible.

  The second hook member 139 that can rotate around the hook shaft 142 at both ends of the slide lower guide 135, that is, the lower roller support unit 149 is illustrated by a hook biasing spring 80 so as to be engageable with the second hook pin 140. 11 (b) is urged to rotate in the direction of arrow G. When the second hook member 139 as a connecting member is engaged with the second hook pin 140, the lower roller support unit 149 is integrated with the upper roller support unit 148. Then, a slide unit 152 shown in FIG. 10B is formed in which a conveyance nip is formed by the driving roller 117a and the driven roller 117b.

  The slide unit 152 according to the present embodiment follows the turning force generated by the loop twist generated between the roller pairs 120, 115, and 117 when conveying a long sheet in the sheet conveying direction. It has a slide configuration that slides in the shift direction. This prevents the problem that skew becomes noticeable due to loop twist.

  Next, a configuration for sliding the slide unit 152 will be described with reference to FIG. 11 (c) and FIGS. 12 (a) to 12 (c). FIG. 11C is a front view showing only the upper roller support unit 148 provided with the upper conveyance guide plate 128. FIG. 12 is a front view showing the slide unit 152, the upper conveyance guide plate 128, and the lower conveyance guide plate 129. FIG. 12A shows a state in which the slide unit 152 is in the designated position, and FIG. 12B shows a state in which the slide unit 152 slides to the near side (left side in the figure). Further, FIG. 12C shows a state in which the slide unit 152 is slid to the back side (right side in FIG. 12).

  As a structure of the slide mechanism, on the upper conveyance guide plate 128 (see FIGS. 9 and 11C) attached so as to be fixed to the apparatus main body (118a) (see FIG. 17) of the feeding buffer device 118, A slide base 159 is attached. A linear bearing 151 is attached to the slide upper guide 132 of the upper roller support unit 148. The upper roller support unit 148 is mounted on the upper conveyance guide plate 128 with the linear bearing 151 facing the slide table 159. As a result, the linear bearing 151 and the slide base 159 are coupled, and the upper roller support unit 148 is supported so as to be slidable in the front-back direction (left-right direction in FIG. 12) with respect to the upper transport guide plate 128. .

  As described above, the slide unit 152 including both the support units 148 and 149 integrated by the engagement of the second hook member 139 and the second hook pin 140 is slidably supported by the slide base 159 and the linear bearing 151.

  Next, the slide configuration of the slide unit 152 will be described with reference to FIGS. FIG. 13 is a plan view showing the slide center positioning portion 46 of the slide urging portion in FIG. 10A as viewed from above. FIG. 13A shows a state in which the slide unit 152 is not slid and is in the center position of the designation, and FIG. 13B shows a state in which the slide unit 152 is slid to the near side, and FIG. c) shows a state in which the slide unit 152 slides to the back side.

  As shown in FIG. 13A, the slide cam member 137 is attached to the slide upper guide 132 (upper roller support unit 148), and is attached to the apparatus main body (support portion 118a in FIG. 17) so as to face this. The slide center positioning portion 46 is disposed. The slide center positioning portion 46 includes a support member 65 having a fixing portion 65a fixed to the apparatus main body (support portion 118a) side, a rotation support shaft 66 attached to the support member 65 in the vertical direction, and a rotation support shaft. 66, and a roller support member 138 extending at one end thereof.

  Further, the slide center positioning portion 46 includes a support member 67 attached to the roller support member 138 on the side facing the slide cam member 137 and a roller member 69 rotatably supported on the support member 67 by a shaft 68. ing. The roller support member 138 is urged toward the slide cam member 137 by a compression spring 70 attached to the inner surface of the fixed portion 65a on the side opposite to the roller member 69 at the other end.

  In the slide center positioning portion 46 having the above configuration, the roller support member 138 is urged by the compression spring 70 and rotates about the rotation support shaft 66 in the clockwise direction of FIG. 69 elastically contacts (elastically contacts) the cam groove 71 of the slide cam member 137.

  The cam groove 71 is formed in a triangular shape having a concave portion at the center in plan view and having two oblique sides extending obliquely toward the slide center positioning portion 46 with the recessed portion as a top portion. Such a cam groove 71 includes a first engagement portion 71a that is most recessed corresponding to the nominal position shown in FIG. 13A, and a second engagement that corresponds to the near-side slide position shown in FIG. 13B. Part 71b, and a third engagement part 71c corresponding to the back side slide position shown in FIG.

  13A, the roller member 69 is elastically engaged with the first engagement portion 71a of the cam groove 71, so that the slide unit 152 (see FIG. 12A) moves the slide cam member 137. It stays stably at the designated position.

  13B, the roller member 69 is elastically engaged with the second engagement portion 71b that is the slope of the cam groove 71, so that the slide unit 152 is interposed via the slide cam member 137. A force constantly applied toward the center in the front-back direction is received.

  Further, at the back side slide position in FIG. 13C, the roller member 69 is elastically engaged with the third engaging portion 71 c that is the slope of the cam groove 71, so that the slide unit 152 is interposed via the slide cam member 137. A force constantly applied toward the center in the front-back direction is received.

  As a result, when the slide unit 152 is slid by the turning force of the loop twist of the conveyed sheet to eliminate the loop twist, the slide unit 152 is automatically called when the sheet passes the feed buffer roller pair 117. It can be returned to the position.

  The upper roller support unit 148 has a cam groove 71 for returning the slide unit 152, which is supported by the slide mechanism and moves in the width direction perpendicular to the sheet conveying direction, to the home position (the position of FIG. 13A). A cam member 137 is disposed. The slide mechanism includes a linear bearing 151 and a slide base 159. A roller member (rotating member) that functions to return to the home position when the slide unit 152 is moved while being constantly urged toward the cam groove 71 is provided on the support portion (device main body) 118a of the feeding buffer device 118. ) 69 is arranged. As described above, by configuring the slide mechanism by the slide cam member 137 and the slide center positioning portion 46, the slide unit 152 can be stably slid.

  In the present embodiment, the force relationship of the nip pressure of the feed buffer roller pair 117 is completed within the slide unit 152. That is, the reaction force of the roller pressing spring 156 (FIG. 11B) that applies the nip pressure by urging the driven roller 117b toward the driving roller 117a is engaged with the second hook pin 140 of the support unit 148. This is because it is received by the second hook member 139 of the support unit 149.

  Next, the opening configuration of the transport nip and the transport path will be described with reference to FIG. FIG. 14A is a perspective view showing a state where the transport nip of the feed buffer roller pair 117 and the lower transport guide plate 129 are opened. 14B and 14C show a state in which the upstream direction is viewed from the downstream side of the conveyance path when the conveyance nip of the feed buffer roller pair 117 and the lower conveyance guide plate 129 are opened. It is a figure which shows the state seen from the front view shown and the left side surface.

  As shown in FIG. 14A, an upper and lower guide latch shaft 153 is rotatably supported on the lower conveyance guide plate 129. An operation knob 134, a first hook member 133, and a hook release member 154 shown in FIGS. 14B and 14C are attached to the vertical guide latch shaft 153 in this order.

  The hook release members 154 are attached to both ends of the upper and lower guide latch shafts 153, respectively. As shown in FIGS. 14B and 15A, 15C, and 15D, the hook release member 154 is rotatably supported by hook shafts 142 at both ends of the lower roller support unit 149. Each of the second hook members 139 is attached to a corresponding position.

  The hook release member 154 is formed so as to extend below an overhang portion 139a formed so as to extend from the two second hook members 139 toward the central portion. As a result, the hook release member 154 pushes the overhanging portion 139a at its tip when the vertical guide latch shaft 153 is rotated in the direction of arrow H in FIG. The second hook members 139 are rotated in the opposite directions of FIG. The two second hook members 139 are always urged to rotate by a torsion spring (not shown) so as to be able to return to the position shown in FIG. Further, the first hook member 133 is provided only on the operation knob 134 side of the upper and lower guide latch shaft 153.

  Further, the upper / lower guide latch shaft 153 is constantly urged counterclockwise in FIG. 14A by a torsion spring (not shown). A first hook pin 155 that engages the first hook member 133 is fixed to one end portion (front side) of the upper conveyance guide plate 128. The first hook member 133 on the lower conveyance guide plate 129 side engages with the first hook pin 155 on the upper conveyance guide plate 128 side, so that the lower conveyance guide plate 129 is connected to the upper conveyance guide plate 128 and integrated. Make it.

  The first hook member 133, the first hook pin 155, the second hook member 139, the second hook pin 140, and the operation knob 134 constitute the connection mechanism of the present invention. This coupling mechanism can function as follows with the lower conveyance guide plate 129 approaching the upper conveyance guide plate 128 so that the driven roller 117b is brought into pressure contact with the driving roller 117a to form a conveyance nip. That is, in this state, the two roller support units 148 and 149 are connected to each other so that the both support units 148 and 149 can be integrally moved with respect to the both conveying guide plates 128 and 129, and the upper and lower sides are connected. The conveyance guide plates 128 and 129 are connected.

  Further, the first hook member 133 and the first hook pin 155 constitute a first lock portion of the present invention that connects the lower conveyance guide plate 129 to the upper conveyance guide plate 128. Furthermore, the second hook member 139 and the second hook pin 140 constitute a second lock portion of the present invention that connects the lower roller support unit 149 to the upper roller support unit 148. Further, the operation knob 134 operates the first and second lock portions simultaneously to connect and release the upper and lower roller support units 148 and 149 and to connect the upper and lower transport guide plates 128 and 129. An operation unit of the present invention that can be operated in conjunction with release is configured. The operation knob (operation unit) 134 is a second hook member (connection member) of the upper roller support unit 148 and the lower roller support unit 149 so that the drive roller 117a and the driven roller 117b can be separated from each other. The connection by 139 is released.

  Here, an operation when the conveyance nip of the feed buffer roller pair 117 and the lower conveyance guide plate 129 are opened will be described.

  First, when the operation knob 134 is rotated in the direction of arrow H in FIG. 14C against the urging force of a torsion spring (not shown), the upper and lower guide latch shaft 153, the first hook member 133, and the hook release member 154 rotate all at once in the same direction. Then, the first hook member 133 is rotated in the direction of arrow H, so that the engagement with the first hook pin 155 on the upper conveyance guide plate 128 side is released. At the same time, the hook release member 154 rotates in the direction of arrow H, so that the two second hook members 139 rotate in the direction of arrow I in FIGS. 14B and 15C, respectively. The engagement with the two hook pins 140 is released.

  For this reason, the first hook member 133 is disengaged from the first hook pin 155, and the second stage disengagement from the second hook pin 140 is followed by the second step disengagement from the first hook pin 155. The conveyance guide plate 129 rotates around the connecting pin 88 and the support member 87. As a result, the upper roller support unit 148 is detached from the lower roller support unit 149, and the lower conveyance guide plate 129 is separated from the upper conveyance guide plate 128. Therefore, the conveyance nip of the feed buffer roller pair 117 and the conveyance path formed between the lower conveyance guide plate 129 and the upper conveyance guide plate 128 are opened.

  In order to make it easier to understand the operation described here, the second hook member 139, the hook release member 154, and the upper and lower guide latch shafts 153 are shown in FIGS. 15 (a), (b), (c), and (d), respectively. Are a perspective view, a left side view, a front view, and a bottom view. In FIG. 15, the arrow H direction and the arrow I direction described in FIG. 14 are similarly described.

  By the turning operation of the operation knob 134 in the direction of arrow H, the conveyance path formed by the upper conveyance guide plate 128 and the lower conveyance guide plate 129 and the conveyance nip of the feed buffer roller pair 117 are both released. A lower roller support unit 149 is disposed inside the lower conveyance guide plate 129.

  In the state of FIG. 14A in which the conveyance path is opened, the driven roller 117b is driven while the lower roller support unit 149 (not shown in FIG. 14A) is supported by the lower conveyance guide plate 129. It is greatly separated from the roller 117a (not shown in FIG. 14A). Therefore, it is possible to provide the slide unit 152 that greatly improves the accessibility and visibility during the jam processing for removing the sheet staying in the feeding buffer device 118.

  Further, when the opened conveyance path and the conveyance nip between the pair of feed buffer rollers 117 are returned to the original state, the operation order described above may be reversed. First, the operation knob 134 is picked and rotated and held in the same arrow H direction as described above. Thereby, the 1st hook member 133 and the 2nd hook member 139 are hold | maintained in the state which each rotated in the same direction as the above.

  Further, in this state, the lower conveyance guide plate 129 is moved closer to the upper conveyance guide plate 128, and the rotation operation of the operation knob 134 is completed. Thus, the first hook member 133 is rotated by the spring force of a torsion spring (not shown) and engages with the first hook pin 155 to form a conveyance path. At the same time, the second hook member 139 is engaged with the second hook pin 140 by the spring force of a torsion spring (not shown) to form the transport nip of the feed buffer roller pair 117, and the integrated slide unit 152 is formed. The

  Here, the configuration related to the slide unit 152 in the sheet conveying apparatus of the present embodiment is schematically shown in FIG. Since each part is functionally shown in FIG. 17, the positions, shapes, and sizes of the second hook member 139, the linear bearing 151, the slide base 159, the roller pressure spring 156, and the like are different from those in the other drawings.

  As shown in FIG. 17, in the present embodiment, an upper conveyance guide plate 128 is fixed to a support portion 118 a in the apparatus main body of the feed buffer device 118, and a lower conveyance guide plate 129 with respect to the upper conveyance guide plate 128. Are connected so as to be freely opened and closed.

  A driving roller 117a is supported on the upper conveyance guide plate 128 via a slide base 159 fixed on the upper conveyance guide plate 128 and a linear bearing 151 that freely moves on the slide base 159 in the thrust direction. Yes. Thus, the driving roller 117a is supported so as to be reciprocally movable within a predetermined distance in the arrow Q direction. Further, the upper conveyance guide plate 128 is provided with an opening 128a that is sized so as to allow the drive roller 117a to protrude downward and to move in the sliding direction.

  The driven roller 117b is reciprocated on the lower conveyance guide plate 129 in the range of a predetermined distance in the direction of arrow Q integrally with the driving roller 117a while the second hook member 139 and the second hook pin 140 are engaged. It is supported freely. In the lower conveyance guide plate 129, an opening 129a corresponding to the driven roller 117b is formed to face the opening 128a. The opening 129a is formed in a size that allows the driven roller 117b to protrude upward and allows movement in the sliding direction.

  The driven roller 117b has a holder 146 (see FIG. 5) so that both end portions protrude outward of the lower roller support unit 149 by roller pressure springs 156 attached to the support portion 149a in the lower roller support unit 149. 11 (b)). As a result, as shown in FIG. 17, the first hook member 133 is engaged with the first hook pin 155 and the second hook member 139 is engaged with the second hook pin 140. A slide unit 152 in which the side conveyance guide plate 129 is closed is formed.

  With the above configuration, in this embodiment, the reaction force of the roller pressing spring 156 that biases the driven roller 117b to apply the nip pressure can be received by the second hook member 139 engaged with the second hook pin 140. . For this reason, the force relationship of the nip pressure of the feed buffer roller pair 117 can be completed in the slide unit 152.

  Here, in order to make it easier to understand the effect of the present embodiment, a comparative example shown in FIG. 18 will be described. This comparative example shows the technology on which the present invention is based.

  That is, in FIG. 18, the guide members 242a and 242b that form the sheet conveyance path 242 are opened, so that jam processing can be performed. The roller 12a of the pre-registration roller 12 is supported by the guide member 242a, the roller 12b is supported by the guide member 242b, and the guide member 242b is supported to be openable with respect to the guide member 242a. The guide members 242a and 242b and the rollers 12a and 12b of the pre-registration roller 12 are connected to a slide mechanism 79 supported on the apparatus body side, and the whole is configured to be slidable in the thrust direction by the slide mechanism 79. ing.

  The roller 12b of the pre-registration roller 12 has a pressure contact spring 39 supported by a support portion 38 on the apparatus main body side in a state where the guide member 242b is close to the guide member 242a side and forms a sheet conveyance path 242. To form a conveyance nip.

  However, in this configuration, although the workability at the time of jam processing can be improved, the slide mechanism 79 receives the urging force of the pressure contact spring 39 in addition to supporting the total weight of the guide members 242a and 242b and the rollers 12a and 12b. You must slide in the For this reason, the load at the time of slide movement becomes large, and a new problem such as impairing improvement in image printing performance such as skew feeding and horizontal registration occurs.

  In contrast to such a comparative example, in this embodiment, the force relationship of the nip pressure of the feed buffer roller pair 117 is completed within the slide unit 152, so the linear buffer 151 as a slide mechanism is connected to the feed buffer roller pair 117. The nip pressure is not carried on the back. For this reason, the feeding buffer roller pair 117 may be slid in a state where only the weight of the entire slide unit 152 is supported by the linear bearing 151 without receiving the urging force of the roller pressing spring 156. As a result, the sliding operation of the slide unit 152 can be realized with a low sliding resistance, and the feed buffer roller pair 117 that follows the slide with respect to the turning force of the loop torsion can be obtained.

  Therefore, according to the present embodiment, the urging force for urging the driven roller 117b to the drive roller 117a is applied to the linear bearing 151 for forming the conveyance nip while improving the workability and visibility at the time of jam processing. I will not let you. For this reason, the load at the time of slide movement can be reduced, and image printing performance, such as skew feeding and horizontal registration, can be improved.

<Second Embodiment>
Next, a second embodiment according to the present invention will be described with reference to FIG. In the first embodiment, the slide unit 152 is slid to follow the loop twist generated between the registration roller pair 120, the pre-registration roller pair 115, and the feeding buffer roller pair 117. On the other hand, the present embodiment is different in that the slide unit 152 is actively slid by the slide drive unit 83 having the slide drive motor 157. In this embodiment, the linear bearing portion in the slide configuration, the transport nip of the feed buffer roller pair 117, and the transport path opening configuration are the same as those in the first embodiment and are redundant. Omitted.

  FIG. 16A is a view when the slide drive motor 157 holds the drive roller 117a at the center position of the designation without shifting. FIG. 16B is a diagram when the slide drive motor 157 shifts the drive roller 117a to the near side (left side in the figure). FIG. 16C is a view when the slide drive motor 157 shifts the drive roller 117a to the back side (right side in the figure). FIG. 16D is a view when the slide drive unit 83 is viewed from the back side (the right side of FIG. 16C). FIG. 16E is a view of the slide drive unit 83 of FIG. 16D as viewed from the oblique front side.

  As shown in FIGS. 16A to 16E, a feed buffer input gear 131 is attached to one end of the rotating shaft 117c of the drive roller 117a. A sleeve portion 89a, which is an attachment portion of the rack 89 in the slide drive portion 83, is attached to the extension portion at one end of the rotating shaft 117c in a fitted state. The sleeve portion 89a is coupled to one end of the rotating shaft 117c in a state that allows the driving roller 117a to rotate and restricts movement in the thrust direction.

  The slide drive unit 83 has a slide drive motor 157 disposed in the apparatus main body of the feed buffer device 118. A pinion 85 is attached to the rotation shaft 157 a of the slide drive motor 157. A large-diameter transmission gear 84 that meshes with the pinion 85 and a small-diameter pinion 86 that is integrally provided at the distal end of the transmission gear 84 are rotated by a support member (not shown) in the main body of the feeding buffer device 118. It is supported freely. A holder portion 82 is provided integrally with the rack 89.

  The holder portion 82 is formed in a “reverse U-shape” extending upward from the rack 89 portion. In the state where the pinion 86 is inserted into the opening 82 a formed in the “reverse U-shaped portion”, the transmission gear 84 and the pinion 86 on the transmission gear 84 side of the “reverse U-shaped portion” Is slidably supported by the shaft portion between the two.

  In the slide drive unit 83 having such a configuration, when the slide drive motor 157 is driven by the control of the control unit 50 (see FIG. 1), the pinion 86 rotated through the pinion 85 and the transmission gear 84 thrusts the rack 89. Move to. Thus, for example, when the slide drive motor 157 is rotated forward, the slide unit 152 moves from the front side of the apparatus main body to the back side (that is, in the arrow Y direction in FIG. 16C) by pulling the drive roller 117a. Be made. On the other hand, at the time of reverse rotation of the slide drive motor 157, the slide unit 152 is moved from the front side of the apparatus main body to the back side (that is, the arrow X direction in FIG. 16B) by pressing the drive roller 117a.

  As described above, the slide unit 152 according to the present exemplary embodiment is configured so that the sheet conveyance direction is determined by the driving force of the slide drive motor 157 serving as a drive source in a state where the entire weight is supported by the slide mechanism including the linear bearing 151 and the slide base 159. It is moved in the orthogonal width direction.

  Since the slide drive unit 83 is provided, the slide unit 152 can perform the thrust movement operation of the drive roller 117a by the drive of the slide drive motor 157. For this reason, the sheet S sandwiched by the pair of feeding buffer rollers 117 can be appropriately shifted under the control of the control unit 50. Also according to this embodiment, substantially the same effect as that of the first embodiment can be obtained.

  DESCRIPTION OF SYMBOLS 96 ... Image forming part, 100 ... Image forming apparatus, 117a ... 1st roller (drive roller), 117b ... 2nd roller (driven roller), 118 ... Sheet conveying apparatus (feed buffer apparatus), 118a ... Main body (feed) Supporting portion of the sending buffer device), 128... First conveying guide plate (upper conveying guide plate), 129... Second conveying guide plate (lower conveying guide plate), 133 and 155. 1 hook member, 1st hook pin), 134 ... operation part (operation knob part), 139, 140 ... connection mechanism, 2nd lock part (2nd hook member (connection member), 2nd hook pin), 148 ... 1st roller Support unit (upper roller support unit), 149 ... second roller support unit (lower roller support unit), 151 ... slide mechanism (linear bearing), 152 ... slide unit , 156 ... urging member, a spring member (roller pressing spring), 157 ... driving source (slide drive motor), S ... Sheet

Claims (7)

A first transport guide plate supported by the apparatus body;
A second conveyance guide plate supported to be openable and closable with respect to the first conveyance guide plate;
A first roller support unit having a first roller and disposed on the first transport guide plate;
A second roller supporting unit disposed on the second transport guide plate, the second roller having a second roller biased by a biasing member so as to face the first roller;
When the second conveyance guide plate is opened with respect to the first conveyance guide plate, the second roller support unit is separated from the first roller support unit so that the second roller is separated from the first roller. A sheet conveying device,
A slide mechanism for supporting the first and second roller support units integrally with the first and second transport guide plates so as to be movable in a width direction orthogonal to the sheet transport direction;
The first and second roller support units are in a state where the second conveyance guide plate is brought close to the first conveyance guide plate so as to form a conveyance nip by pressing the second roller against the first roller. A connection that connects the first and second roller support units and connects the first and second transport guide plates so as to be a slide unit that is movable relative to the first and second transport guide plates. A mechanism,
A sheet conveying apparatus. The coupling mechanism is
A first lock portion connecting the second transport guide plate to the first transport guide plate;
A second lock portion connecting the second roller support unit to the first roller support unit;
An operation that can be operated by operating the first and second lock portions simultaneously to interlock the release of the connection of the first and second roller support units and the release of the connection of the first and second transport guide plates. And having a part,
The sheet conveying apparatus according to claim 1, A first roller support unit having a first roller;
A second roller support unit having a second roller pressed against the first roller and movable relative to the first roller support unit such that the first roller and the second roller are separated from each other;
A spring member that press-contacts the first roller and the second roller;
A connecting member that connects the first and second roller support units while receiving a reaction force of the spring member so that the first roller and the second roller are pressed against each other by the spring member;
A slide mechanism that supports the first and second roller support units connected by the connection member as a slide unit so as to be slidable in a width direction orthogonal to the sheet conveying direction;
An operation unit for releasing the connection of the first roller support unit and the second roller support unit by the connecting member so that the first roller and the second roller can be separated from each other; Have
A sheet conveying apparatus. The slide unit is pulled by the sheet so as to follow the turning force generated by the loop twist of the sheet nipped by the first roller and the second roller while being supported by the slide mechanism. Move in the direction,
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The slide unit is moved in the width direction by a driving force of a driving source while being carried by the slide mechanism.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The first roller is a driving roller that rotates by receiving a driving force,
The second roller is a driven roller that rotates in contact with the driving roller.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A sheet conveying apparatus according to any one of claims 1 to 6,
An image forming unit that forms an image on the conveyed sheet,
An image forming apparatus.

Images