JP2008273697A - Sheet conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper discharging device capable of forming corrugations on a paper sheet by a simple structure. <P>SOLUTION: This sheet conveying device comprises a rotatingly driven discharge roll 42 and a plurality of pinch rolls 43 installed along the axial direction of the discharge roll 42 and brought into contact with the outer peripheral surface of the discharge roll 42 to hold paper between themselves and the discharge roll 42 before conveyance. The positions of the pinch rolls 43 on the discharge roll 42 are different from each other in the paper conveying direction. The pinch rolls 43a disposed at the axial both ends of the discharge roll 42 are brought into contact with the discharge roll 42 at a position higher than the pinch rolls 43b disposed adjacently to the pinch rolls 43a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus and an image forming apparatus.

  2. Description of the Related Art Conventionally, in a paper conveyance device (sheet conveyance device) provided in an image forming apparatus such as a printer, corrugation is made in a direction substantially perpendicular to the conveyance direction on discharged paper (sheet) to improve running stability. Improvements are being made. This is because when the paper curled by the roller of the fixing device is discharged, the paper curls from the leading edge and falls off the discharge tray, or the curled paper leading edge is landed near the discharge port. This is to prevent page misalignment caused by discharging the next sheet with the trailing edge remaining in the discharge port.

For this reason, a corrugation roller for creating corrugation is provided separately from the roller that imparts a conveying force to the paper, a rib is provided on the frame, and a corrugation recess is formed on the paper with the rib and the drive roller. What forms the corrugation by providing the part which protruded in the edge part is known (for example, patent documents 1, 2).
Japanese Patent Laid-Open No. 05-043110 JP 2005-034486 A

  However, the technique of separately providing a corrugation roller for producing corrugation has a problem of increasing the cost. Furthermore, the provision of the corrugation roller increases the number of parts that come into contact with the paper, which increases the risk of the paper becoming dirty.

  Also, in the technology for corrugating with ribs, the ribs are not movable, so depending on the strength of the paper, the corrugation may be too strong and the paper may be streaked. Conversely, corrugation may not be formed depending on the paper. (In other words, there is a problem that the running of the seat becomes unstable).

  Furthermore, in the technique of providing a protruding portion at the roller end, the position where the paper is nipped and the portion for forming the corrugation are too close, and depending on the strength of the paper, there may be a mark that is bent on the paper. There was a problem.

  The present invention has been made from the above-described technical background, and an object thereof is to provide a sheet conveying apparatus and an image forming apparatus that can form corrugation on a sheet with a simple configuration.

  In order to solve the above-described problem, a sheet conveying apparatus according to the present invention is provided with a conveying member that is rotationally driven, and a plurality of the conveying members that are arranged along the axial direction of the conveying member, and that contacts the outer peripheral surface of the conveying member. An abutting member that contacts and conveys the sheet between the conveying member and the abutting position of the abutting member with respect to the conveying member is a part or all of the abutting members. It differs from each other in the sheet conveying direction.

  According to a second aspect of the present invention, in the first aspect of the present invention, the contact member is a cylindrical member that rotates following the conveying member.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the contact members disposed at both ends in the axial direction of the transport member are disposed next to the contact member. Abutting on the conveying member at a position higher than the abutting member.

  In order to solve the above-described problem, an image forming apparatus according to a fourth aspect of the present invention includes an apparatus main body, a sheet storage unit that stores a sheet, and a supply unit that supplies a sheet from the sheet storage unit to the apparatus main body. An image forming unit that forms an image on the sheet supplied from the supply unit, a fixing unit that thermally fixes the image formed by the image forming unit to the sheet, and the sheet that is thermally fixed by the fixing unit. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is discharged outside the apparatus main body.

  According to the first aspect of the present invention, corrugation is formed on the sheet by the conveyance member and the contact member by making the contact positions of the plurality of contact members different from each other in the sheet conveyance direction. Corrugation can be formed on the sheet with a simple configuration.

  According to the second aspect of the present invention, since the contact member rotates, the contact member does not slide with the sheet to become a conveyance resistance, so that the corrugation can be smoothly formed on the sheet. Become.

  According to the invention described in claim 3, since both ends of the sheet are upwardly corrugated, the sheet is difficult to bend downward, the landing point is far from the discharge port, and the stacking stability of the discharged sheet is improved. Is possible.

  According to the fourth aspect of the present invention, it is possible to obtain an inexpensive image forming apparatus having a good sheet discharge performance by using a sheet conveying apparatus capable of forming corrugation on a sheet with a simple configuration.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a conceptual diagram of a tandem type color printer as an image forming apparatus according to an embodiment of the present invention. This color printer is configured to execute a printing operation based on image data sent from, for example, a personal computer or a scanner. Of course, the image forming apparatus may be configured as a copier or facsimile provided with a scanner, or a multifunction machine provided with these functions. Furthermore, a monochrome printer or a color printer other than a tandem type may be used.

  In FIG. 1, an image forming unit (image forming means) 2 is arranged in the vertical direction in a substantially central portion of a tandem color printer main body (apparatus main body) 1. Further, in the color printer main body 1, a sheet on which a plurality of color toner images formed by the image forming unit 2 are transferred is adsorbed to one side (left side in the figure) of the image forming unit 2. Is disposed on the other side of the image forming unit 2 (on the right side in the figure), the control unit 4 having a control circuit or the like is oblique to the image forming unit 2. A power supply circuit unit 5 including a high-voltage power supply circuit and the like is disposed above.

  In addition, a sheet feeding cassette (sheet storing means) 6 for storing and feeding a sheet 18 or the like as a sheet on which an image is transferred is disposed at the bottom of the color printer main body 1.

  The image forming unit 2 includes four image forming units 7Y, 7M, 7C, and 7K that form toner images of yellow (Y), magenta (M), cyan (C), and black (K) in order from the bottom. These four image forming units 7Y, 7M, 7C, and 7K are arranged in series at regular intervals along the vertical direction.

  These four image forming units 7Y, 7M, 7C, and 7K are configured in the same manner except for the color of the image to be formed, and roughly divided, as shown in FIG. 1, holds an image that rotates at a predetermined rotation speed. Photosensitive drum 8 (8Y, 8M, 8C, 8K), and a charging roll 9 (9Y, 9M, 9C, 9K) for primary charging that uniformly charges the surface of the photosensitive drum 8 to a predetermined potential. An exposure device 10 (10Y, 10M, 10C, 10K) that exposes an image corresponding to each color on the surface of the photosensitive drum 8 to form an electrostatic latent image, and a static image formed on the photosensitive drum 8. A developing device 11 (11Y, 11M, 11C, 11K) that develops the electrostatic latent image with the corresponding color toner, and a static eliminating device 21 (21Y, 21M, 21C) that removes charge remaining on the photosensitive drum 8 after development. , 21K) and on the photosensitive drum 8 Cleaning cleans the residual untransferred toner unit 12 (12Y, 12M, 12C, 12K) and supplies the toner to the developing device 11 toner cartridge 13 is configured from (13Y, 13M, 13C, 13K) and.

  As shown in FIG. 1, the developing device 11 supplies two-component or one-component developer contained therein to the developing roll 14 (14Y, 14M, 14C, 14K) while stirring, and the developing roll 14 While controlling the layer thickness of the developer supplied to the photosensitive drum 8, the developer is conveyed to a developing area facing the photosensitive drum 8, and the electrostatic latent image formed on the surface of the photosensitive drum 8 is formed with toner of a predetermined color. It is comprised so that it may develop.

  The yellow (Y), magenta (M), cyan (C), and black (K) developing devices 11Y, 11M, 11C, and 11K correspond to yellow (Y), magenta (M), and cyan (M). C) and toner cartridges 13Y, 13M, 13C, and 13K as developer containers for supplying toner of each color of black (K).

  The static eliminator 21 removes residual charges after development by irradiating the photosensitive drum 8 with light so that the drum surface is uniformly charged in the next image formation.

  Further, as shown in FIG. 1, the cleaning device 12 removes the transfer residual toner remaining on the surface of the photosensitive drum 8 with a cleaning blade 15 (15Y, 15M, 15C, 15K), and the removed transfer residual toner. The cleaning device 12 is transported and accommodated inside.

  As shown in FIG. 1, a control unit 4 is disposed inside the color printer main body 1, and the control unit 4 includes, for example, an image processing device 16 that performs predetermined image processing on image data. Is provided. The image processing device 16 sequentially outputs image data of each color of yellow (Y), magenta (M), cyan (C), and black (K) to the exposure device 10, and the exposure device 10 according to the image data. The four laser beams LB emitted in this manner are scanned and exposed on the respective photosensitive drums 8Y, 8M, 8C, and 8K to form electrostatic latent images. The electrostatic latent images formed on the photosensitive drums 8Y, 8M, 8C, and 8K are respectively yellow (Y), magenta (M), cyan (C), and black by the developing devices 11Y, 11M, 11C, and 11K. It is developed as a toner image of each color of (K).

  Further, as shown in FIG. 1, the sheet conveying belt unit 3 includes a sheet conveying belt 17 that circulates and moves as an endless belt, and the sheet conveying belt 17 includes the image forming units 7Y, 7M, and 7C. , Transported in a state of electrostatically adsorbing paper 18 as a transfer material onto which toner images of each color of yellow (Y), magenta (M), cyan (C), and black (K) formed at 7K are transferred. Is configured to do.

  As shown in FIG. 1, the paper transport belt 17 is stretched with a predetermined tension between a drive roll 19 and a driven roll 20 as stretch rolls arranged along the vertical direction. A drive roll 19 that is rotationally driven by a motor is configured to circulate counterclockwise in FIG. 1 at a predetermined speed.

  For example, the distance between the drive roll 19 and the driven roll 20 is set to a length substantially equal to the length of the A3 size paper 18, but is not limited thereto, and may be set arbitrarily. As the paper transport belt 17, for example, a flexible synthetic resin film such as polyimide is formed in an endless belt shape.

  Further, as shown in FIG. 1, an attracting roll 22 for electrostatically attracting the paper 18 to the surface of the paper transport belt 17 is brought into contact with the surface of the drive roll 19 via the paper transport belt 17. Is arranged. The suction roll 22 is configured, for example, by covering the surface of a metal cored bar with conductive rubber in the same manner as the charging rolls 9 of the image forming units 7Y, 7M, 7C, and 7K. A predetermined bias voltage for adsorption is applied. The suction roll 22 is configured to electrostatically charge the paper 18 sent from the paper feed cassette 6 and suck the paper 18 on the surface of the paper transport belt 17. Note that the suction roll 22 is not necessarily provided.

  Toner of each color of yellow (Y), magenta (M), cyan (C), and black (K) formed on the photosensitive drums 8Y, 8M, 8C, and 8K of the image forming units 7Y, 7M, 7C, and 7K As shown in FIG. 1, the images are sequentially transferred in multiple layers onto the sheet 18 conveyed while being attracted to the surface of the sheet conveying belt 17 while being superimposed on each other by the transfer rolls 23Y, 23M, 23C, and 23K. Is done. The transfer rolls 23Y, 23M, 23C, and 23K are integrally attached to the paper transport belt unit 3, and these transfer rolls 23Y, 23M, 23C, and 23K are attached to the photosensitive drums 8Y, 8M, 8C, and 8K. The nip portions that are in pressure contact with each other serve as an image transfer region where the toner image is transferred onto the paper 18.

  As shown in FIG. 1, the paper 18 is fed from a paper feed cassette 6 disposed at the bottom of the printer main body 1 and conveyed to the printer main body 1. The paper feed cassette 6 includes a paper tray 24 in which paper 18 having a desired size and material is accommodated. In addition, a pickup roll 35 that nips the uppermost sheet 18 is disposed immediately above the sheet tray 24. As a result, the paper 18 having a desired size and material is taken out from the paper tray 24 one by one by the pick-up roll 35 and fed by the feeding roll (feeding means) 25 and one sheet by the paper roll 26. The paper is fed in a separated state and conveyed to a suction position on the paper conveying belt 17 at a predetermined timing via a registration roll 27 serving as a paper feeding means.

  The feeding roll 25 and the pickup roll 35 are provided on the color printer main body 1 side, and the separating roll 26 is provided on the paper feeding cassette 6 side.

  Here, a roll that combines the function of the pickup roll 35 and the function of the feeding roll 25 may be used. Further, instead of the separating roll 26, a pad type separating means having a predetermined friction resistance with respect to the paper 18 to be taken out may be used.

  As the sheet, for example, various sizes such as A4 size, A3 size, B5 size, B4 size, and sheet-like materials of various materials such as thick paper such as plain paper and coated paper, and OHP sheets are used.

  As shown in FIG. 1, the paper 18 on which the toner images of each color of yellow (Y), magenta (M), cyan (C), and black (K) are transferred in a multiple manner has a rigidity ( After being separated from the paper transport belt 17 by so-called stiffness, the paper is transported along a transport path 28 to a fixing device (fixing means) 29. The fixing device 29 applies heat and pressure to the paper 18 to fix the toner image on the paper 18.

  The paper transport belt 17 and the fixing device 29 are arranged close to each other, and the paper 18 separated from the paper transport belt 17 is transported to the fixing device 29 by the transport force of the paper transport belt 17. The fixing device 29 is rotationally driven in a state in which the heating roll 30 and the pressure belt 31 are in pressure contact with each other, and the sheet 18 is passed through a nip portion formed between the heating roll 30 and the pressure belt 31. The fixing process is performed by heat and pressure.

  Thereafter, the paper 18 on which the toner images of the respective colors are fixed is discharged by a paper discharge device (sheet transport device) 32 with the print surface facing down on a paper discharge tray 33 provided on the upper portion of the color printer main body 1. The paper is discharged from the exit, and the printing operation ends.

  Note that a color printer can print an image of a desired color such as monochrome as well as a color image, and yellow (Y), magenta (M), magenta (M), and the like depending on the color of the image to be printed. A toner image is formed by all or part of the cyan (C) and black (K) image forming units 7Y, 7M, 7C, and 7K.

  In FIG. 1, reference numeral 34 denotes an operation panel provided with a display unit such as a liquid crystal panel attached to the front of the printer main body 1. The operation panel 34 displays the status of the printer and is necessary. It is configured to perform operations and the like.

  Next, the paper discharge device 32 of the image forming apparatus having such a schematic configuration will be described with reference to FIGS. Here, FIG. 2 is a perspective view showing a paper discharge device of the image forming apparatus and a housing to which the paper discharge device is attached according to an embodiment of the present invention, FIG. 3 is a front view of FIG. 2, and FIG. 5 is a cross-sectional view taken along the line A ′, FIG. 5 is an explanatory diagram showing a three-dimensional positional relationship between the discharge roll and the pinch roll constituting the paper discharge device, and FIG. 6 is a view of the discharge roll and the pinch roll constituting the paper discharge device. FIG. 7 is a perspective view showing paper discharged from a paper discharge device attached to the housing.

  As shown in FIGS. 2 to 4, the paper discharge device 32 is provided in the housing 50 together with the fixing device 29.

  Here, the fixing device 29 is rotated by a rotational force of a rotation driving unit (not shown), and a heating roll 30 in which a heat source 30a such as a halogen lamp is attached, and a heated rotation in pressure contact with the heating roll 30. The pressure belt 31 is provided.

  Then, the sheet 18 having the toner image transferred to the image transfer portion of the image forming unit 2 passes through the fixing portion P where the heating roll 30 and the pressure belt 31 are in pressure contact with each other in the sheet conveying direction (sheet conveying direction) D. Heat and a pressure force are applied when passing toward the toner, and the toner image is fixed on the paper 18 by this.

  Then, the sheet 18 on which the toner image is fixed is discharged onto the sheet discharge tray 33 (FIG. 1) outside the printer body 1 on the downstream side in the sheet conveyance direction D from the fixing unit P in such a fixing device 29. A paper discharge device (sheet conveying device) 32 is disposed.

  As shown in detail in FIG. 5, the paper discharge device 32 includes a discharge roll (conveying member) 42 that is rotated by the rotational force of a motor (rotational drive source) 40 transmitted via a drive system 41 configured by, for example, a gear train. And a pinch roll (contact member) 43 that is in pressure contact with the discharge roll 42 and rotates.

  The discharge roll 42 is made of rubber attached to the shaft 42a at a predetermined interval from a shaft 42a having a gear 42b meshing with the drive system 41 attached to one end thereof and rotatably supported by a bearing (not shown). And a cylindrical roll body 42c. The discharge roll 42 is attached to the inside of a lid 50a for maintenance or the like attached to the housing 50 so as to be openable and closable. When the lid 50a is closed, the gear 42b meshes with the drive system 41 and its outer peripheral surface. (To be more precise, the outer peripheral surface of the roll main body 42 c abuts on the pinch roll 43.

  As shown in the figure, a plurality of pinch rolls 43 are separated from each other so as to correspond to the roll main body 42c of the discharge roll 42, and two axes that are coaxially arranged alternately along the axial direction of the discharge roll 42. Arranged on S1 and S2.

  That is, in the five pinch rolls 43 arranged along the axial direction of the discharge rolls 42, a total of three pinch rolls 43a on both sides and in the center are located on the axis S1, and the total number of pinch rolls 43a between these pinch rolls 43a. The two pinch rolls 43b are located on an axis S2 that is moved by a predetermined rotation angle counterclockwise from the axis S1 around the axis of the discharge roll 42 in FIG. Therefore, the contact position of the pinch roll 43 with respect to the discharge roll 42 in the sheet conveyance direction D differs between the pinch roll 43a and the pinch roll 43b.

  More specifically, in FIG. 6, when the contact position of the pinch roll 43a with respect to the discharge roll 42 in the paper transport direction D is N1, the discharge roll 42 of the pinch roll 43b in the paper transport direction D is shown in FIG. The contact position N2 with respect to is upstream of the contact position N1 in the paper transport direction D. Further, the contact position N1 of the pinch roll 43a is higher by the height H than the contact position N2 of the pinch roll 43b.

  For example, as shown in FIG. 5, the pinch roll 43 formed of a fluororesin includes a cylindrical body portion 43-1 that contacts the roll body 42c of the discharge roll 42, and a shaft portion that protrudes from both ends of the body portion. 43-2. The shaft 43-2 is rotatably supported by a support 50b (FIGS. 2 and 3) which is a pair of protrusions formed in the housing 50, so that the pinch roll 43 can freely rotate. It has become. Such a pinch roll 43 abuts on the discharge roll 42 to transmit the rotational force of the discharge roll 42 and is driven to rotate, and transports the paper 18 in cooperation with the discharge roll 42.

  A torsion spring that generates a pressure contact force between the pinch roll 43 and the discharge roll 42 by biasing the shaft portion 43-2 of the pinch roll 43 toward the discharge roll 42 is provided on the support portion 50b (see FIG. (Not shown) is installed. As described above, when the lid 50 a is closed, the discharge roll 42 comes into pressure contact with the pinch roll 43. This is because the pinch roll 43 moves backward against the elastic force of the torsion spring 57 by the discharge roll 42.

  According to the paper discharge device 32 configured as described above, the discharge roll 42 and the pinch roll 43 sandwich and rotate the paper 18 by the pressing force, whereby the rotational force of the rolls 42 and 43 is transmitted to the paper 18 and the paper 18 18 moves along the paper transport direction D and is discharged onto the paper discharge tray 33.

  As described above, the contact position of the pinch roll 43 with respect to the discharge roll 42 in the sheet conveyance direction D is different between the pinch roll 43a and the pinch roll 43b. Only a height H (FIG. 6) is formed. Therefore, when the paper 18 is passed through the paper discharge device 32 composed of the discharge roll 42 and the pinch roll 43, the contact position N1 and the contact position N2 are placed on the paper 18 as shown in FIG. Corrugation corresponding to the difference in height H is formed in a direction substantially perpendicular to the transport direction.

  Therefore, according to the present embodiment, a simple configuration in which a plurality of contact positions between the discharge roll 42 and the pinch roll 43 (the pinch roll 43a and the pinch roll 43b) is formed (that is, a special for forming a corrugation). Corrugation can be formed on the paper 18 without requiring a special member or a special shape.

  Further, the contact position N1 of the pinch roll 43a disposed at both ends of the discharge roll 42 in the axial direction is higher than the contact position N2 of the pinch roll 43b disposed adjacent thereto by a height H, so that Thus, both ends of the paper 18 are upwardly corrugated. Accordingly, the sheet 18 is difficult to bend downward, the landing point is far from the discharge port, and the stacking stability of the discharged sheet 18 is improved.

  Therefore, an inexpensive image forming apparatus having good sheet discharging performance can be obtained by adopting the sheet discharging apparatus 32 having a configuration capable of forming corrugation on the sheet 18 with such a simple configuration in the image forming apparatus.

  In the present embodiment, the pinch rolls 43 are arranged on the two axes S1 and S2 that are alternately coaxial along the axial direction of the discharge roll 42. That is, of the plurality of pinch rolls 43, Are partially different from each other in the paper transport direction D, but may be all different. Further, the method of changing the contact position may not be alternate.

  Further, although the pinch roll 43 that is a cylindrical member that rotates following the discharge roll 42 is used as the contact member, a flat pad-shaped member may be used as the contact member. However, according to the configuration of the present embodiment, since the pinch roll 43 rotates, the pinch roll 43 does not slide with the paper 18 to be transported and does not become transport resistance. Accordingly, corrugation can be smoothly formed on the paper 18.

  Further, in the present embodiment, the contact position N1 of the pinch roll 43a disposed at both ends in the axial direction of the discharge roll 42 is set higher than the contact position N2 of the pinch roll 43b disposed adjacent thereto. If the stacking stability of the paper 18 is not a problem, the contact position may be the same or low.

  In the above description, the case where the sheet conveying apparatus of the present invention is mounted on an image forming apparatus for recording toner is shown. However, for example, an ink jet type image forming apparatus for recording with ejected ink or ATM (automatic cash deposit and withdrawal) And the like can be used for various apparatuses to which a sheet conveying apparatus can be mounted.

1 is a conceptual diagram of a tandem type color printer that is an image forming apparatus as an embodiment of the present invention. FIG. 1 is a perspective view showing a paper discharge device of an image forming apparatus according to an embodiment of the present invention and a housing to which the paper discharge device is attached. FIG. 3 is a front view of FIG. 2. FIG. 4 is a cross-sectional view taken along line A-A ′ of FIG. 3. It is explanatory drawing which shows the positional relationship of the discharge roll and pinch roll which comprise a paper discharge apparatus in three dimensions. It is explanatory drawing which shows the positional relationship of the discharge roll and pinch roll which comprise a paper discharge apparatus from an axial direction. FIG. 6 is a perspective view illustrating a sheet discharged from a sheet discharge device attached to a housing.

Explanation of symbols

1 Color printer (device main unit)
2 Image forming unit (image forming means)
6 Paper cassette (sheet storage means)
25 Feeding roll (supplying means)
29 Fixing device (fixing means)
32 Paper discharge device (sheet transport device)
42 Discharge roll (conveying member)
43, 43a, 43b Pinch roll (contact member)
43-1 Body 43-2 Shaft D Paper transport direction (sheet transport direction)

Claims (4)

A conveying member that is rotationally driven;
A plurality of members provided along the axial direction of the conveying member, and an abutting member that contacts the outer peripheral surface of the conveying member and conveys the sheet with the conveying member interposed therebetween,
The contact position of the contact member with respect to the transport member is different from each other in the sheet transport direction for some or all of the plurality of contact members.
A sheet conveying apparatus. The contact member is a cylindrical member that rotates following the conveying member.
The sheet conveying apparatus according to claim 1. The contact members disposed at both ends of the transport member in the axial direction are in contact with the transport member at a position higher than the contact member disposed next to the contact member.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The device body;
Sheet storage means for storing the sheet;
Supply means for supplying a sheet from the sheet storage means to the apparatus main body;
Image forming means for forming an image on the sheet supplied from the supply means;
Fixing means for thermally fixing the image formed by the image forming means to the sheet;
The sheet conveying apparatus according to any one of claims 1 to 3, wherein the sheet thermally fixed by the fixing unit is discharged out of the apparatus main body.
An image forming apparatus comprising:

Images