JP2007062879A - Sheet conveying apparatus, sheet processing apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a sheet by a necessary number of roller pairs when conveying a sheet by three or more conveying roller pairs.
A sheet conveying apparatus includes three or more conveying roller pairs that are arranged in a sheet conveying direction and convey a sheet, and a sheet conveyed by the conveying roller pair extends over three or more conveying roller pairs. In the case of a long sheet, the sheet conveying function of at least one conveying roller pair 172 out of three or more conveying roller pairs is reduced or stopped.
[Selection] Figure 3

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, a sheet processing apparatus that performs processing on a sheet, and an image forming apparatus that forms an image on a sheet.

  Conventionally, there is a sheet conveying apparatus that conveys a sheet. This sheet conveying apparatus is often installed in a sheet handling apparatus such as an image reading apparatus, an automatic document feeder, or a sheet processing apparatus.

  Examples of the image forming apparatus include a copying machine, a printer, a facsimile, and a composite device thereof that form an image on a sheet. The automatic document feeder has a function of automatically supplying a document to the image reading device. Examples of the sheet processing apparatus include a punching apparatus that punches holes in sheets and sheet bundles, a bending apparatus that bends sheet bundles, and a binding apparatus (stapler) that binds sheet bundles.

  In order to convey a sheet, the sheet conveying apparatus has a plurality of roller pairs as a plurality of rotating body pairs arranged along the sheet conveying path (see Patent Document 1).

JP-A-11-116121

  By the way, in the conventional sheet conveying apparatus, the arrangement interval of the roller pairs is set to be equal to or smaller than the length of the minimum size sheet (for example, a postcard) among the conveyed sheets. . However, when a conventional sheet conveying apparatus conveys a long sheet of A4, B5, LTR size or the like having a high conveyance ratio, it may be conveyed across three or more roller pairs.

  Originally, in order to take over and convey a sheet, it is sufficient that two roller pairs are engaged with one sheet. For this reason, since the conventional sheet conveying apparatus conveys a long sheet straddling three or more roller pairs when conveying a long sheet, there existed a roller pair which is carrying out useless operation | movement. In addition, the sheet conveyance speed of each roller pair is slightly different due to wear of the roller pair, rotation unevenness, and the like.

  For this reason, the conventional sheet conveying apparatus may cause the sheet to jam or damage the sheet by loosening the sheet or applying a pulling force to the sheet. Further, the conventional sheet conveying apparatus has large roller wear, operating noise, and power consumption.

  As described above, the sheet processing apparatus and the image forming apparatus equipped with the sheet conveying apparatus that generates a jam or damages the sheet have poor sheet processing efficiency and image forming efficiency.

  SUMMARY OF THE INVENTION The present invention provides a sheet conveying apparatus that reduces jamming and scratches on a sheet by minimizing the number of rotating body pairs that are actually conveyed with a sheet sandwiched therebetween. There is.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet processing apparatus that includes a sheet conveying device that does not easily cause a jam or damage the sheet, and has improved sheet processing efficiency.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet conveying device that hardly causes jamming or scratches on a sheet and has improved image forming efficiency.

  The sheet conveying apparatus of the present invention includes three or more rotating body pairs arranged in the sheet conveying direction and conveying the sheet, and the sheets conveyed by the rotating body pair are the three or more rotating body pairs. In the case of a long sheet having a length in the sheet conveying direction, the sheet conveying function of at least one rotating body pair among the three or more rotating body pairs is reduced or stopped.

  The sheet conveying apparatus of the present invention is characterized in that when the sheet conveyed by the pair of rotating bodies is a long sheet, the rotating bodies of the at least one rotating body pair are separated from each other.

  The sheet processing apparatus of the present invention includes a sheet conveying apparatus that conveys a sheet, and a sheet processing unit that performs processing on the sheet conveyed by the sheet conveying apparatus, and the sheet conveying apparatus is any one of the above It is a sheet conveying apparatus.

  An image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet, a sheet conveying device that is disposed on at least one of the upstream side and the downstream side of the image forming unit, and conveys the sheet, The sheet conveying apparatus is any one of the sheet conveying apparatuses described above.

  In the sheet conveying apparatus of the present invention, when conveying a long sheet, the sheet conveying function of at least one rotating body pair is reduced or stopped. The number can be minimized as compared with the prior art. For this reason, the sheet conveying apparatus of the present invention can reduce the occurrence of a jam or damage to the sheet.

  In the sheet conveying apparatus of the present invention, when the sheet is a long sheet, the rotating members of at least one rotating member pair are separated from each other, so that it is possible to reduce the occurrence of a jam or damage to the sheet. it can.

  The sheet processing apparatus of the present invention includes a sheet conveying apparatus that hardly causes jamming or scratches on a sheet, and can increase sheet processing efficiency.

  The image forming apparatus of the present invention includes a sheet conveying device that hardly causes jamming or scratches on a sheet, and can increase image forming efficiency.

  Hereinafter, a sheet conveying apparatus, a sheet processing apparatus, and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Image forming device)
(Description of configuration of image forming apparatus)
FIG. 1 is a schematic cross-sectional view along the sheet conveying direction of a copying machine as an image forming apparatus. Note that the image forming apparatus includes a copying machine, a printer, a facsimile, and a composite device that forms an image on a sheet, and is not limited to the copying machine.

  An apparatus main body (copier main body) 300A of the copier 300 includes a platen glass 906, a light source 907, a lens system 908, a paper feeding unit 909, an image forming unit 902, an automatic document feeder 500, a sheet processing apparatus 100, and the like. ing. The automatic document feeder 500 is not necessarily required.

  The platen glass 906 is a document table on which a document is placed. The automatic document feeder 500 has a function of automatically feeding a document to the platen glass 906. The sheet processing apparatus 100 has a function of selectively performing a binding process on an image-formed sheet discharged from the copying machine main body.

  The paper feeding unit 909 includes a pedestal 912 having cassettes 910 and 911 and a deck 913 that store recording sheets P and are detachable from the apparatus main body 300A. The image forming unit 902 includes a cylindrical photosensitive drum 914, a developing unit 915, a transfer charging unit 916, a separation charging unit 917, a cleaner 918, a primary charging unit, which are sequentially arranged around the photosensitive drum 914 in the clockwise direction. A container 919 and the like. A conveyance device 920, a fixing device 904, a discharge roller pair 905, and the like are disposed on the downstream side of the image forming unit 902.

(Description of operation of image forming apparatus)
When a paper feed signal is output from the control device 900 provided on the apparatus main body 300A side, the sheet P is fed from the cassettes 910, 911 or the deck 913. On the other hand, the light reflected from the light source 907 on the document D placed on the platen glass 906 is applied to the photosensitive drum 914 through the lens system 908. The photosensitive drum 914 is charged in advance by a primary charger 919, and an electrostatic latent image is formed by irradiation with light. The electrostatic latent image is developed by the developing device 915 to become a toner image.

  The sheet P fed from the sheet feeding unit 909 is corrected in skew by the registration roller 901 and further fed to the image forming unit 902 at a proper timing. In the image forming unit 902, the toner image on the photosensitive drum 914 is transferred to the sheet P that has been sent by the transfer charger 916. The sheet P to which the toner image has been transferred is charged to a polarity opposite to that of the transfer charger 916 by the separation charger 917 and separated from the photosensitive drum 914.

  The separated sheet P is conveyed to the fixing device 904 by the conveying device 920, and the toner image is permanently fixed by the fixing device 904. The sheet P on which the toner image is fixed is discharged by the discharge roller pair 905 with the toner image facing upward. Alternatively, when the sheet P is discharged with the toner image on the lower side, after the image is fixed, the sheet P is conveyed to the sheet reversing path 930 and reversed before being discharged. In this way, the sheet P fed from the sheet feeding unit 909 forms a toner image and is discharged to the sheet processing apparatus 100.

  The apparatus main body 300A of the copying machine 300 is controlled by a control device 900, and the sheet processing apparatus 100 is controlled by a control circuit 150. The control circuit 150 may be incorporated in the control device 900 so that the control device 900 controls the entire copier 300 including the sheet processing apparatus 100.

  The copier 300 according to the present embodiment has a contact / separation mechanism 140 described later on one of a plurality of conveyance roller pairs (not shown) that conveys a sheet disposed upstream or downstream of the image forming unit 902. Is provided. For this reason, when the copier 300 conveys a long sheet, the sheet conveying function of at least one roller pair is reduced or stopped, so the number of roller pairs that actually convey the sheet while sandwiching the sheet. Can be reduced to a minimum as compared with the prior art. Accordingly, the copying machine 300 can reduce the occurrence of jams or scratches on the sheet, and can improve the image forming efficiency. Further, the amount of wear, operating noise, and power consumption of the rollers of the copying machine 300 are reduced.

(Sheet processing equipment)
FIG. 2 is a schematic cross-sectional view of the sheet processing apparatus along the sheet conveyance direction.

  The sheet processing apparatus 100 has a function of receiving a sheet discharged from the apparatus main body 300A of the image forming apparatus 300 by the entrance roller pair 102 and selectively performing sheet bundle alignment processing and binding processing. Note that the sheet processing apparatus is not limited to the process of binding the sheet bundle. A punching process for making a hole in a sheet or a sheet bundle, a bending process for folding a sheet bundle, or the like may be performed.

  The entrance sensor 101 detects the delivery timing of the sheet sent from the apparatus main body 300A. The inlet sensor 101 detects the leading edge and the trailing edge of the passing sheet, and detects the sheet length in cooperation with the control circuit 150.

  The sheet conveyed by the entrance roller pair 102 passes through the lateral registration detection sensor 104 by conveyance of the conveyance roller pair 170 having a contact / separation mechanism and guidance of the conveyance path 103, and further, the conveyance roller pairs 106 and 107. Is conveyed downstream. Thereafter, the sheet is conveyed through the intermediate conveyance path 105 as the guide path to the conveyance roller pair 110 and the conveyance roller pair 172 having the second contact / separation mechanism, and reaches the buffer roller pair 115.

  When the sheet is discharged to the upper tray 136, the upper path switching flapper 118 is switched by a drive source such as a solenoid (not shown), and after being guided to the upper path conveying path 117 by the guidance of the flapper 118, the upper discharge roller 120 is discharged to the upper tray 136.

  When the sheet is fed into the saddle unit 135 as a sheet processing unit, the sheet is guided to the bundle conveyance path 121 by the upper path switching flapper 118. Thereafter, the sheet is conveyed in the bundle conveyance path 121 by the conveyance roller pair 122, the buffer roller pair 123, and the bundle conveyance roller pair 124. The sheet is conveyed to the saddle path 133 when the saddle path switching flapper 125 is switched by a driving source such as a solenoid (not shown), and sent to the saddle unit 135 by the pair of saddle inlet rollers 134. The saddle unit 135 bundles the sheets, then binds the middle (saddle, saddle stitching), and folds the portion into a booklet.

  When the sheet is discharged to the lower tray 137, the saddle switching flapper 125 is switched to the solid line position, and then guided to the lower path 126 and discharged to the processing tray 138 by the lower discharge roller pair 128. The sheet discharged to the processing tray 138 is brought into contact with the stopper 139 by the returning operation of the rotating paddle 131 and the knurled belt 129 and is aligned at the rear end. Thereafter, the sheet is subjected to a binding process by a stapler 132 as a sheet processing unit as needed, and is discharged to the lower tray 137 by a bundle discharge roller pair 130.

  In the sheet processing apparatus 100 of the present embodiment, a contact / separation mechanism 140 described later is provided on a pair of conveyance rollers 170 and 172 that conveys a sheet. For this reason, the sheet processing apparatus 100 lowers or stops the sheet conveyance function of at least one roller pair when conveying a long sheet. The number can be reduced to a minimum as compared with the prior art. Therefore, the sheet processing apparatus 100 is less likely to cause jams or scratches on the sheet, and can improve sheet processing efficiency. In addition, the wear amount, operating noise, and power consumption of the rollers of the sheet processing apparatus 100 are reduced.

(Sheet conveying device)
The sheet conveying device 200 is arranged in the sheet conveying direction, and includes a pair of inlet rollers 102, a pair of conveying rollers 170, 106, 107, 110, 172, and a pair of buffer rollers 115 as a pair of rotating bodies that convey sheets. A roller pair 122, a buffer roller pair 123, and the like are provided.

  The arrangement interval of these roller pairs is set to be equal to or less than the length of the minimum size sheet so that the minimum size (for example, postcard) of the transported sheets can be conveyed. Among these roller pairs, for example, there are long sheets straddling the three conveyance roller pairs 110 and 172 and the buffer roller pair 115. Long sheets include A4, B5, and LTR size sheets that are longer than postcards.

  Whether the sheet is a long sheet is determined and transmitted to the inlet sensor 101 and the control circuit 150 as information transmission means. In addition, sheet size information input by the user from the operation panel 921 of the apparatus main body 300A of the copier 300 may be determined by the control device 900 and transmitted via the control circuit 150 or directly. Therefore, the operation panel 921 also corresponds to information transmission means.

  One of the roller pairs is provided with a contact / separation mechanism, which will be described later, as release means for stopping the sheet conveying function. In the sheet conveying apparatus 200 of this embodiment, the conveying roller pair 170, 172 is provided with a contact / separation mechanism. The case where the contact / separation mechanism is provided in the conveyance roller pair indicated by reference numeral 172 will be described, and the description of the case where it is provided in the conveyance roller pair indicated by reference numeral 170 will be omitted.

  FIG. 3 is a perspective view of an abutment / separation mechanism 140 as a release means.

  The contact / separation mechanism 140 has a function of separating the separation roller 172b from the conveyance roller 172a and stopping the sheet conveyance function of the conveyance roller pair 172 when long sheet information is obtained from the control circuit 150 (see FIG. 2). I have. The transport roller 172a is a drive roller as a drive rotator that is rotated by a motor (not shown). The separation roller 172b is a driven roller as a driven rotating body that rotates in contact with the conveying roller 172a.

  The separation frame 224 is moved up and down in the direction of arrow F by the guide of the shaft 223 protruding from the fixed frame 221. Normally, the separation frame 224 stands by at the home position when the flag 224a is detected by the home position sensor 225. When the drive gear 227 is rotated clockwise in FIG. 3 by a drive source such as a stepping motor (not shown), the driven gear 226 meshed with the drive gear 227 is rotated counterclockwise. When the driven gear 226 rotates counterclockwise, the rack 141 with which the driven gear 226 is engaged is lowered. The rack 141 is provided on the separation frame 224. Accordingly, the separation frame 224 is lowered together with the rack 141 in the arrow F direction.

  A long hole 143 is formed in the separation frame 224 along the ascending / descending direction of the separation frame 224. A bearing 142 of the separation roller 172b is provided in the elongated hole 143 so as to be movable up and down. A compression spring 222 is provided in the long hole 143. The compression spring 222 presses the bearing 142 downward.

  Even if the separation frame 224 is lowered and the separation roller 172b comes into contact with the conveying roller 172a, the separation frame 224 continues to be slightly lowered. At this time, the separation roller 172b cannot come into contact with the conveying roller 172a and descend. Therefore, the separation frame 224 is lowered while compressing the compression spring 222, and the separation roller 172b is pressed against the transport roller 172a by the elasticity of the compression spring 222.

  The descending distance of the separation frame 224 is calculated by the control circuit 150 based on the number of pulses of the stepping motor from the home position. The descending distance is calculated in consideration of the type and thickness of the sheet input by the user to the operation panel 921.

  In a state where the separation roller 172b is in pressure contact with the conveyance roller 172a, the conveyance roller 172a is rotated by a driving source (not shown) to convey the sheet.

  When the control circuit 150 determines that the length of the conveyed sheet is a long sheet, the drive gear 227 rotates counterclockwise in FIG. Then, the separation frame 224 rises to separate the separation roller 172b from the conveyance roller 172a. The separation frame 224 stops when the flag 224a is detected by the home position sensor 225.

  As a result, the conveying roller pair 172 is stopped from the sheet conveying function. The long sheet is not conveyed to the conveyance roller pair 172 but is conveyed by the conveyance roller pair 110 and the second buffer roller pair 115.

  The conveyance roller 172a continues to rotate even after the separation roller 172b is separated, and assists the sheet conveyance of the conveyance roller pair 110 and the second buffer roller pair 115. Not only in this configuration, but also by reducing or not transmitting the conveying force of the conveying roller pair 172, problems due to the difference in sheet conveying speed between the roller pairs can be solved. For example, after the separation roller 172b is separated, the rotation of the conveyance roller 172a may be stopped so that the sheet slides on the circumferential surface of the conveyance roller, or a clutch is provided between the conveyance roller 172a and the drive source. The drive transmission may be cut off and the vehicle may idle.

  In the above description, the force for pressing the separation roller 172b against the conveyance roller 172b and the distance for separating the separation roller 172b from the conveyance roller 172a can be changed according to the thickness and material of the sheet. The change is performed by the control circuit 150 controlling a stepping motor that is a drive source of the drive gear 227. Information on the thickness and material of the sheet is obtained from user input information from the operation panel 921 or from detection information from sensors provided in the apparatus main body 300A and the sheet processing apparatus 100.

  As described above, when conveying a long sheet, the sheet conveying apparatus 200 according to the present embodiment reduces or stops the sheet conveying function of at least one roller pair. For this reason, the number of roller pairs that are actually conveyed with the sheet sandwiched therebetween can be reduced to a necessary minimum and less than the conventional one. Therefore, the sheet conveying apparatus 200 can reduce the tension and slack of the sheet due to the difference in sheet conveying speed between the pair of rollers, which has conventionally been generated by conveying one sheet by three or more roller pairs. it can. Therefore, the sheet conveying apparatus 200 is less likely to damage the sheet or cause a jam.

  In addition, the sheet conveying apparatus 200 reduces the operating noise and power consumption by reducing the number of roller pairs that are actually conveyed while sandwiching the sheet. Further, the wear amount of the roller pair provided in the contact / separation mechanism 140 can be reduced.

  As shown in FIG. 4, the conveyance roller pair 172 protrudes into the intermediate conveyance path 105 and conveys the sheet P.

  FIG. 5 is a diagram illustrating a state in which the separation roller 172b of the conveyance roller pair 172 is separated from the conveyance roller 172a. Even if the separation roller 172 b is separated from the conveyance roller 172 a, the outer peripheral portion B as a rotation peripheral surface remains in the intermediate conveyance path 105. As a result, the sheet P is guided by the outer peripheral portion B of the separation roller 172b, and the leading end of the sheet P is not caught by the escape portion C of the intermediate conveyance path 105 on the downstream side of the separation roller 172b.

FIG. 6 is a diagram showing in detail the separation state of the separation roller 172b. The amount G of the separation roller 172b protruding into the intermediate transport path 105 is
G ≧ 0
It is. For this reason, the separation roller 172b forms a part of the intermediate conveyance path 105 and serves as a guide wall for the sheet P.

  FIG. 7 is a diagram when the separation amount of the separation roller 172b is increased. If the separation roller 172b moves to a position where it is retracted from the intermediate conveyance path 105, the leading edge of the sheet P rides on the end D of the escape portion C of the intermediate conveyance path 105, which causes a jam.

  As described above, the sheet can be conveyed in a stable state by using the outer peripheral surface of the pair of conveying rollers 172 as a sheet conveying guide.

  Instead of the contact / separation mechanism 140 serving as the release means described above, for example, an electromagnetic clutch may be provided between the transport roller 172a and the drive source. The electromagnetic clutch cuts off drive transmission based on the sheet size information indicating that the sheet is a long sheet, and causes the separation roller 172b to idle while keeping the pressure contact with the conveying roller 172a.

  Also in this case, the sheet conveying device is configured to reduce or stop the sheet conveying function of at least one roller pair when conveying a long sheet. The number can be reduced to a minimum as compared with the prior art. For this reason, the sheet conveying apparatus can reduce the occurrence of a jam or damage to the sheet. Further, since the contact / separation mechanism is unnecessary, the apparatus can be simplified and downsized.

  Further, since the number of roller pairs that are actually conveyed with the sheet interposed therebetween is reduced, it is possible to reduce operating noise, power consumption, and roller wear.

1 is a schematic cross-sectional view along a sheet conveying direction of a copying machine as an image forming apparatus according to an embodiment of the present invention. It is a schematic sectional view along the sheet conveyance direction in the sheet processing apparatus of the embodiment of the present invention. FIG. 6 is a perspective view of a contact / separation mechanism for bringing a separation roller into contact with and separating from the conveyance roller in the sheet conveyance apparatus according to the embodiment of the present invention. FIG. 6 is a diagram illustrating a positional relationship between a pair of conveyance rollers and an intermediate conveyance path in a sheet conveyance apparatus. FIG. 5 is a diagram illustrating a state in which the separation rollers of the pair of conveyance rollers are separated from the conveyance rollers. FIG. 5 is a diagram showing the amount of protrusion in the intermediate conveyance path when the separation roller is separated from the conveyance roller. In FIG. 4, it is a figure at the time of increasing the separation amount of a separation roller.

Explanation of symbols

B Outer peripheral part of rotating roller (rotating peripheral surface)
P sheet 100 sheet processing apparatus 101 entrance sensor 105 intermediate conveyance path (guide path)
110 Conveying roller pair (rotating body pair)
115 Buffer roller pair (Rotating body pair)
132 Stapler (sheet processing means)
135 Saddle unit (sheet processing means)
140 Contact / Separation Mechanism 150 Control Circuit 172 Conveying Roller Pair (Rotating Body Pair)
172a Conveying roller (drive rotating body)
172b Separating roller (driven rotor)
200 Sheet conveying apparatus 300 Copying machine (image forming apparatus)
300A Copying Machine Main Body 500 Automatic Document Feeding Device 900 Control Device 901 Registration Roller 902 Image Forming Unit 921 Operation Panel 950 Control Device

Claims (6)

Comprising three or more rotating body pairs arranged in a sheet conveying direction and conveying the sheet;
When the sheet conveyed by the rotating body pair is a long sheet having a length in the sheet conveying direction across the three or more rotating body pairs, at least one rotation of the three or more rotating body pairs. A sheet conveying apparatus that reduces or stops a sheet conveying function of a body pair.   2. The sheet conveying apparatus according to claim 1, wherein when the sheet conveyed by the pair of rotating bodies is a long sheet, the rotating bodies of the at least one rotating body pair are separated from each other. The rotating body pair includes a driving rotating body that rotates by driving, and a driven rotating body that rotates in contact with the driving rotating body,
3. The sheet conveying apparatus according to claim 1, wherein when the sheet conveyed by the pair of rotating bodies is a long sheet, the driven rotating body is moved toward and away from the driving rotating body. A guide path for guiding a sheet conveyed by the pair of rotating bodies;
The seat according to any one of claims 1 to 3, wherein a rotational peripheral surface of the rotating body when the at least one rotating body pair is separated forms a part of a side wall of the guide path. Conveying device. A sheet conveying device for conveying a sheet;
Sheet processing means for processing the sheet conveyed by the sheet conveying device,
The sheet processing apparatus according to claim 1, wherein the sheet conveying apparatus is the sheet conveying apparatus according to claim 1. An image forming unit for forming an image on a sheet;
A sheet conveying device arranged on at least one of the upstream side and the downstream side of the image forming unit to convey the sheet,
The image forming apparatus, wherein the sheet conveying apparatus is the sheet conveying apparatus according to claim 1.

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