JP2008110875A - Sheet conveying device, image reading device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet conveying device capable of conveying a sheet to a downstream side of a sheet conveying passage in a second conveying means with stable linear velocity while holding the sheet even when the sheet such as cardboard having high rigidity is used. <P>SOLUTION: A belt conveying means 8A is arranged in an outer direction of a first conveying passage, and is provided with a conveying belt 82 driven by a grip roller 81 and conveying the paper sheet to a nip part. The belt conveying means 8A is provided with the conveying belt 82 made of rubber, pulleys 83 and 84 holding the conveying belt 82 so that the conveying belt 82 can travel, and a belt supporting member 86 pivotally supporting the pulleys 83 and 84 so as to be rotatable. The pulleys 83 and 84 are supported by the belt supporting member 86 so as to keep an inter-shaft distance constant. The conveyance belt 82 is characterized to satisfy following conditions; the thickness of the belt is 1.5 mm or more, hardness of the rubber of the belt (JIS K6325A) is 35-85 degrees, and an expansion ratio of the conveying belt 82 is 10-5%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus, a copier equipped with the sheet conveying apparatus, a facsimile, a printer, a printing machine, an inkjet recording apparatus, an image reading apparatus such as a scanner, or a combination machine combining at least two of them. The present invention relates to an image forming apparatus.

  Conventionally, image forming apparatuses such as copiers, facsimiles, printers, printers, ink jet recording apparatuses, etc., including PPC (plain paper copier: plain paper copiers), etc., are designed to reduce the size of the entire apparatus. For transporting and supplying an image forming medium or a sheet-like recording medium (hereinafter referred to as “sheet”), which is a medium on which the image is formed, from the sheet storage means or the sheet stacking means for stacking sheets to the image forming means body The conveying means also tends to be downsized. Hereinafter, the sheet storing means for storing the sheet will be described as a representative.

  Further, the image forming apparatus generally has a model corresponding to various sheet sizes (hereinafter referred to as “paper size”) and sheet types (hereinafter referred to as “paper type”). In such an image forming apparatus model, for example, a sheet (hereinafter, referred to as “paper” illustratively) having several paper sizes and types is stored in advance in a sheet storage unit, and the user selects as appropriate. The sheet can be fed from the sheet storing means or the sheet automatically selected by the image forming apparatus. Accordingly, in the case of such a configuration, the sheet storage unit occupies more space in the image forming apparatus and consumes it, so that the demand for downsizing the transport unit is increased.

For these reasons, the conveyance path formed between the sheet storage unit and the image forming unit main body in the image forming apparatus depends on the positional relationship between the two. The space occupied is reduced. As a result, in order to change the conveyance direction continuously and smoothly on the conveyance path, a curved portion having a curved shape is provided, and the curvature radius of the curved portion is used as a sheet normally used in an image forming apparatus. Is set to a relatively small radius that allows the standard recording paper to be conveyed.
As a sheet conveying apparatus in such an image forming apparatus, for example, a conventional technique described in Japanese Patent Application Laid-Open No. 2004-338923 can be cited (see Patent Document 1). That is, as shown in FIGS. 6 and 7 of the same publication, a sheet storage unit that stores a predetermined number of sheets of a predetermined size and type on each stage on the lower side of the image forming unit main body. A sheet feeding tray is arranged, and between the sheet feeding tray and the image forming unit main body, one sheet is pulled out in a substantially horizontal direction of the sheet feeding tray which is the selected stage, and the upper image forming unit main body The sheet conveying device for feeding toward is provided.

Hereinafter, the reference numerals shown in the drawings of the above-mentioned Japanese Patent Application Laid-Open No. 2004-338923 will be described with parentheses as appropriate, and the sheet (P) in the paper feed tray (1) will be 1 in the well-known FRR separation system. The sheet is separated and sent out, and is conveyed to the main body of the image forming unit through a conveyance path having a curvature portion formed by the upper guide plate (8) and the lower guide plate (7). The curvature portion is formed of a curved fixed guide member including an upper guide plate (8) and a lower guide plate (7). When the sheet (P) passes through the curvature portion, the lower guide plate ( 7) As the conveyance proceeds along the sheet 7), the path of the sheet (P) is corrected so as to be pressed by the upper guide plate (8), and the elastic deformation located at the outlet of the lower guide plate (7) is achieved. The conveying roller pair (5) is reached along the possible guide piece (6). Hereinafter, the upper guide plate (8) and the lower guide plate (7) are referred to as “curved fixed guide members”.
However, in the sheet conveying apparatus configured as described above, when trying to convey a sheet of special paper (P) having high rigidity such as recording paper such as thick paper or an envelope, the curvature radius of the curvature portion of the conveyance path is small. Therefore, since the resistance when the sheet (P) is conveyed while being bent according to the curvature thereof is significantly larger than that of a sheet such as plain paper for copying, a sheet (P ) Cannot be advanced, causing jams and poor conveyance, resulting in a failure to perform a stable feeding operation.

  The above operation will be described in more detail as follows. When the sheet (P) has a leading end (front end) in the conveying direction of the sheet (P) reaches a curved fixed guide member composed of an upper guide plate (8) and a lower guide plate (7), the curved fixed guide The first half of the sheet (P) on the leading end side is curved in the thickness direction by the member. For this reason, when the highly rigid sheet (P) is conveyed, the force with which the highly rigid sheet (P) resists bending increases, and the resistance force that prevents the conveyance also increases. Therefore, the leading end of the highly rigid sheet (P) does not reach the downstream conveying roller pair (5), and the highly rigid sheet (P) is conveyed only by the upstream roller pair (2a, 2b). When the high-rigidity sheet (P) is curved by the curved fixed guide member, the resistance generated from the curved high-rigidity sheet (P) can be obtained only by the conveying force by the upstream roller pair (2a, 2b). As a result, there is a shortage of force that advances in the transport direction relative to the force. For this reason, conveyance failure such as skewing in which the center line of the highly rigid sheet (P) does not coincide with the center line of the conveyance path, or the highly rigid sheet (P) is caught by the curved fixed guide member and stopped. Paper jam is likely to occur.

Therefore, in Japanese Patent Application Laid-Open No. 2004-338923, in a sheet feeding device that conveys a sheet fed from a first conveying unit to a second conveying unit that is positioned downstream in the conveying direction and substantially vertically above. A pair of linear guide members are provided between the first conveyance unit and the second conveyance unit, and a sheet feeding device that conveys a sheet by the guide of the linear guide member has been proposed. According to this paper feeding device, since the guide member is not a curved shape but a straight linear guide member, the conveyance load can be suppressed to a low level, that is, a rapid increase in the load can be suppressed, and paper jams, skews, etc. It is said that poor conveyance can be prevented.
In other words, according to the sheet feeding device, the deformed portion on the conveyed sheet is not concentrated on one curve by the curved guide member, but near the front and rear ends of the linear guide member in the conveyance direction. Since the linear guide member is installed in a slanted posture with a substantially intermediate angle so that the degree of bending at these two places is substantially equal and the same, it can be conveyed at the time of conveyance. It is said that a sudden increase in load can be suppressed. That is, since the sheet changes its traveling direction, the curved portion is divided into two locations: a location where the sheet is delivered from the upstream roller pair to the linear guide member, and a location where the sheet is delivered from the linear guide member to the downstream roller pair. At least, the degree of bending of each portion becomes small, and accordingly, the resistance generated by bending at each portion can be kept low, so that it is possible to avoid a sharp increase in the transport load.

It has the 1st, 2nd conveyance means comprised like the said Unexamined-Japanese-Patent No. 2004-338923 (patent document 1), and it is 2nd between a 1st conveyance means and a 2nd conveyance means. 2. Description of the Related Art There is known a paper feeding device that is provided with a reversing guide member that has an inclined surface that extends to the transporting unit, and the reversing guide member is configured to move toward a second transporting unit (for example, Patent Documents). 2).
According to this paper feeding device, when the rear end of the sheet contacts the reversing guide member, the reversing guide member is displaced in a direction substantially the same as the direction in which the rear end of the sheet is in contact. It is said that it can reduce the playing sound because it can absorb the shock at the time.

In addition, a plurality of sheet storage units that store sheets, a conveyance path and a sheet feeding unit that are individually provided in each sheet storage unit, and the ends of these conveyance paths are joined to one common conveyance path. And at least the conveyance path provided in the sheet accommodation means that accommodates the highly rigid sheet has a radius of curvature of the first curvature portion when joining the common conveyance path provided at the end of the conveyance path. There is known a sheet feeding apparatus that is set to be larger than the radius of curvature of another curvature portion when the conveyance paths of the two are merged (see, for example, Patent Document 3).
According to this sheet feeding device, a highly rigid sheet is curved to the same extent as a normal sheet when it passes through the first curvature portion having a large radius of curvature while traveling on the conveyance path. In contrast, since the sheet is kept curved sufficiently slowly as compared with the normal sheet, the resistance during conveyance can be reduced, and the sheet can be conveyed by reaching the common conveyance path without causing stagnation or delay of the sheet.

The reversing roller pair has a reversing conveyance path for conveying and guiding the sheet fed by the reversing roller pair, and the reversing conveyance path has a direction changing portion for changing the sheet conveying direction. In addition, by disposing a roller that is rotatable inward in the direction changing portion in a direction perpendicular to the sheet conveying direction, the sheet fed into the reverse conveying path is sent out while being brought into contact with the roller. A sheet inverting means provided in a forming apparatus is known (for example, see Patent Document 4).
According to this sheet reversing means, the fed sheet is in the above-mentioned direction changing portion, and the inner contact portion always comes into contact with the roller, and this roller is driven to rotate as the sheet is conveyed in the conveying direction. Compared to the conventional guide plate, the conveyance resistance can be reduced, that is, the frictional resistance generated between the fixed guide member and the moving sheet is eliminated, and the guide for changing the conveyance direction at the direction changing portion. I can do it.

JP 2004-338923 A (pages 1 to 3, FIGS. 1 to 7) Japanese Patent Laying-Open No. 2005-89008 (pages 2 and 3, FIGS. 4 and 5) Japanese Patent Laid-Open No. 10-129883 (pages 1 and 2, FIG. 1) Japanese Patent Laying-Open No. 2005-1771 (pages 1 and 2, FIG. 1)

However, in the sheet conveying device described in Patent Document 1, since the fixing member is arranged for guiding the sheet to be conveyed, the sheet conveying apparatus between the sheet to be conveyed and the fixed guide member is arranged. The speed difference is not eliminated, and there is a problem that a resistance acting in a direction that hinders the conveyance of the sheet is always generated between the two regardless of the shape of the guide member and the installation posture, resulting in a conveyance load.
That is, in the conventional configuration, the effect of avoiding the above-described conveyance failure and jam is insufficient, and the linear guide member causes a conveyance load even if a rapid increase in the conveyance load can be suppressed. It can be said that there is no change. In particular, when a highly rigid paper (sheet) such as thick paper or an envelope is transported, the above-mentioned transport failure, jam, and the trailing sound of the paper become noticeable.

  In the configuration provided with the reversal guide member described in Patent Document 2, even if it is a movable member in the sense that it can be displaced in the direction in which the rear end of the paper is in contact, the guide for changing the orientation of the paper is a fixed guide member. Similarly, when guiding by changing the direction, the relative speed difference between the sheet and the reverse guide member is not eliminated, and a transport load is generated. In particular, when a highly rigid sheet (sheet) such as thick paper or an envelope is conveyed, the above-described conveyance failure, jam, and the trailing sound of the sheet become noticeable.

  In addition, as in the technique described in Patent Document 3, even in a configuration in which a dedicated conveyance path having a predetermined large radius of curvature is provided, the sheet traveling on this dedicated conveyance path is gently curved so that the sheet is removed from the conveyance path. Even if the transport resistance received is reduced, the transport load is similarly generated. In particular, when transporting highly rigid paper (sheets) such as thick paper and envelopes, the above-mentioned transport failure and jamming become noticeable.

  Further, as in the technique described in Patent Document 4, in a configuration in which a movable member such as a roller is provided at a predetermined position of the inner conveyance path portion in the direction change portion of the conveyance path, in the conveyance process, by the inner roller, Even if the frictional resistance between the two in the state where the intermediate portion between the front and rear ends of the seat is supported can be particularly effectively reduced, the state before and after such a state, that is, the outside of the direction changing portion There is a lack of consideration for the conveyance load when the conveyance path portion and the sheet are in contact with each other, and no particular mention is made of the behavior of the sheet leading edge and the sheet trailing edge during the conveyance process. In particular, when a highly rigid sheet (sheet) such as thick paper or an envelope is conveyed, the above-described conveyance failure, jam, and the trailing sound of the sheet become noticeable.

  Accordingly, the applicant of the present application is an invention (hereinafter referred to as “prior application”) that aims to provide a novel sheet conveying apparatus that can solve the problems of the prior art and an image forming apparatus having the sheet conveying apparatus. Proposed). Details of the example to which the invention of the prior application is applied will be described later before the embodiment of the present invention is described. According to the present invention, a compact and space-saving, simple and low-cost configuration, a sheet conveying apparatus excellent in compatibility with sheet types (paper types), an image reading apparatus including the sheet conveying apparatus, and a sheet An image forming apparatus including a conveying device and / or an image reading device can be provided.

  Therefore, in the present invention, even when a sheet having relatively high rigidity (strong waist) such as cardboard is used, the advantages and effects such as space saving, simple configuration, and low cost are left in practical use of the invention of the prior application. A sheet conveying apparatus capable of conveying the sheet without any problem downstream of the sheet conveying path in the second conveying means while holding the sheet, an image reading apparatus including the sheet conveying apparatus, a sheet conveying apparatus, and / or The main object is to realize and provide an image forming apparatus provided with an image reading apparatus. It is another object of the present invention to realize and provide a sheet conveying apparatus capable of obtaining the effects of each claim described later, an image reading apparatus including the sheet conveying apparatus, a sheet conveying apparatus, and / or an image forming apparatus including the image reading apparatus. It is said.

  In order to solve the above-mentioned problems and achieve the above-mentioned object, the present inventors have conducted research and evaluation as described in the examples of the prior inventions described later, examples, etc. As a simple configuration that can transport relatively rigid sheets, such as cardboard and envelopes, without causing poor transport or jamming, regardless of the type of sheet, the simple design of a moving guide means (moving guide) was conceived. As a specific means, the belt conveying means having the simplest configuration has been variously devised and put into practical use. The present invention has been made on the basis of the results supported by such tests.

In order to solve the above-described problems and achieve the above-mentioned object, the invention according to each claim employs the following characteristic means / invention-specific matters (hereinafter referred to as “configuration”).
According to the first aspect of the present invention, a first conveying unit that conveys a sheet, and a sheet that is disposed downstream of the first conveying unit in the sheet conveying direction and that has been conveyed by the first conveying unit is the first conveying unit. Second conveying means for forming a nipping portion for nipping and conveying in a sheet conveying direction different from the sheet conveying direction of the conveying means, and one of the opposing pair forming the nipping portion rotates to generate a driving force. A rotation conveying drive means capable of transmitting, and the other of the opposing pair is disposed in an outer direction of a sheet conveying path formed between the first conveying means and the second conveying means, and the rotating conveyance driving means And a belt conveying unit that is configured to include a belt that conveys the sheet toward the clamping unit, the belt conveying unit including the belt made of an elastic member and at least a pair of belts that hold the belt so that the belt can run. Holding times A member and a support member that rotatably supports each belt holding and rotating member, and each belt holding and rotating member is supported by the support member so as to keep the distance between the axes constant. The belt has a hardness of 40 to 80 degrees, and a percentage ratio of an extension from a circumference of the belt alone when the belt is wound between the belt holding and rotating members. The sheet conveying apparatus is characterized in that an expansion ratio satisfies a condition of 10 to 5%.

  According to a second aspect of the present invention, in the sheet conveying apparatus according to the first aspect, the initial position near the belt in the outer direction of the sheet conveying path formed between the first conveying unit and the second conveying unit. The belt is disposed and has a guide member that guides the sheet to the belt, and the belt is in contact with the sheet when the belt has a hardness of 40 to 80 degrees and the expansion ratio is 4%. The belt satisfies the special condition by disposing the guide member at a position away from the conveyance surface to the extent that the conveyance surface does not interfere with the conveyance surface when the conveyance surface swells in a direction that interferes with the guide member. It is possible to adopt.

  According to a third aspect of the present invention, there is provided a first conveying unit that conveys a sheet, and a sheet that is disposed downstream of the first conveying unit in the sheet conveying direction and that has been conveyed by the first conveying unit. A second conveying unit that forms a nipping unit that nipped and conveys in a sheet conveying direction different from the sheet conveying direction of the first conveying unit, and a first sheet formed between the first conveying unit and the second conveying unit A second sheet conveying path different from the first sheet conveying path, the first sheet conveying path, and the second sheet conveying formed from the conveying path, upstream of the second conveying means to the second conveying means One of the opposed pairs forming the clamping portion is a rotation conveyance driving means capable of transmitting a driving force by rotating. And the other of the opposing pair is the merging conveyance path Belt conveying means disposed in an outer contour direction and including a belt that conveys a sheet toward the sandwiching portion following the rotation conveying driving means, and the belt conveying means includes the belt made of an elastic member, At least a pair of belt holding and rotating members that hold the belt so that the belt can run, and support members that rotatably support the belt holding and rotating members, and each belt holding and rotating member has a constant inter-axis distance. The belt is supported by the support member so as to be held, and the belt has a hardness of 40 to 80 degrees, and the belt when the belt is wound between the belt holding and rotating members. The sheet conveying apparatus is characterized in that an expansion ratio, which is a percentage ratio of expansion from a single circumference, satisfies a condition of 10 to 5%.

  According to a fourth aspect of the present invention, a first conveying unit that conveys a sheet and a sheet that is disposed downstream of the first conveying unit in the sheet conveying direction and that has been conveyed by the first conveying unit is the first conveying unit. Second conveying means for forming a nipping portion for nipping and conveying in a sheet conveying direction different from the sheet conveying direction of the conveying means, and one of the opposing pair forming the nipping portion rotates to generate a driving force. A rotation conveying drive means capable of transmitting, and the other of the opposing pair is disposed in an outer direction of a sheet conveying path formed between the first conveying means and the second conveying means, and the rotating conveyance driving means And a belt conveying unit that is configured to include a belt that conveys the sheet toward the clamping unit, the belt conveying unit including the belt made of an elastic member and at least a pair of belts that hold the belt so that the belt can run. Holding times A member and a support member that rotatably supports each belt holding and rotating member, and each belt holding and rotating member is supported by the support member so as to keep the distance between the axes constant. The belt has a belt hardness of 35 to 85 degrees, and a percentage ratio of an extension from the circumference of the belt alone when the belt is wound between the belt holding and rotating members. The sheet conveying apparatus is characterized in that an expansion ratio satisfies a condition of 10 to 5%.

  Invention of Claim 5 is arrange | positioned in the sheet | seat conveying apparatus of Claim 4, arrange | positioned in the belt vicinity of the outer direction of the sheet conveyance path | route formed between the 1st conveyance means and the 2nd conveyance means, The belt has a guide member for guiding a sheet, and the belt has a hardness of 35 to 85 degrees, and the belt conveying surface that comes into contact with the sheet under the special condition that the expansion ratio is 4%. However, when the belt bulges in a direction that interferes with the guide member, the belt satisfying the special condition can be adopted by disposing the guide member at a position away from the conveyance surface so as not to interfere with the conveyance surface. It is characterized by that.

  According to a sixth aspect of the present invention, there is provided a first conveying unit that conveys a sheet, and a sheet that is disposed downstream of the first conveying unit in the sheet conveying direction and that has been conveyed by the first conveying unit. A second conveying unit that forms a nipping unit that nipped and conveys in a sheet conveying direction different from the sheet conveying direction of the first conveying unit, and a first sheet formed between the first conveying unit and the second conveying unit A second sheet conveying path different from the first sheet conveying path, the first sheet conveying path, and the second sheet conveying formed from the conveying path, upstream of the second conveying means to the second conveying means One of the opposed pairs forming the clamping portion is a rotation conveyance driving means capable of transmitting a driving force by rotating. And the other of the opposing pair is the merging conveyance path Belt conveying means disposed in an outer contour direction and including a belt that conveys a sheet toward the sandwiching portion following the rotation conveying driving means, and the belt conveying means includes the belt made of an elastic member, At least a pair of belt holding and rotating members that hold the belt so that the belt can run, and support members that rotatably support the belt holding and rotating members, and each belt holding and rotating member has a constant inter-axis distance. The belt is supported by the support member so as to be held, and the belt has a hardness of 35 to 85 degrees, and the belt when the belt is wound between the belt holding and rotating members. The sheet conveying apparatus is characterized in that an expansion ratio, which is a percentage ratio of expansion from a single circumference, satisfies a condition of 10 to 5%.

  A seventh aspect of the present invention is the sheet conveying apparatus according to any one of the first to sixth aspects, wherein the belt has a thickness of 1.5 mm or more.

  The invention according to claim 8 is the sheet conveying apparatus according to any one of claims 1 to 7, wherein the belt is any one of ethylene / propylene rubber, chloroprene rubber, urethane rubber, or silicon rubber. It is characterized by that.

  According to a ninth aspect of the invention, in the sheet conveying apparatus according to any one of the first to eighth aspects, the outer direction of the sheet conveying path formed between the first conveying means and the second conveying means A first belt holding and rotating member disposed opposite to the rotary conveyance driving means, and a guide member for guiding a sheet to the belt. A second belt holding and rotating member disposed on the upstream side in the sheet conveying direction of the second conveying means so as to face the first belt holding and rotating member, and the second belt holding and rotating member includes: Positioned on the downstream side in the sheet conveying direction of the second conveying means from the axial center of the rotating member provided on the outer periphery of the conveying means, and on the upstream side in the sheet conveying direction of the second conveying means from the downstream end of the guide member It is characterized by doing.

  According to a tenth aspect of the present invention, in the sheet conveying apparatus according to any one of the first to ninth aspects, the belt conveying means includes a belt in which a leading end of the sheet is held by the belt holding rotating members. It is arrange | positioned so that the conveyance surface of this belt except a part may be contacted.

  The invention according to claim 11 is the sheet conveying apparatus according to any one of claims 1 to 10, wherein the sheet is a sheet having relatively high rigidity.

  A twelfth aspect of the invention is an image forming apparatus comprising the sheet conveying device according to any one of the first to eleventh aspects.

According to the present invention, it is possible to realize and provide a novel sheet conveying apparatus and an image forming apparatus having the sheet conveying apparatus by solving the above problems.
That is, according to the present invention, while maintaining space, a simple configuration, and low cost, regardless of the type of sheet including a sheet having relatively high rigidity such as cardboard, the sheet is held with a belt at a stable linear velocity. It is possible to realize and provide a novel sheet conveying apparatus capable of feeding / conveying without problems to the downstream side of the sheet conveying path in the second conveying unit and an image forming apparatus having the sheet conveying apparatus.

The following are specific effects for each invention described in the claims.
According to the first, third, fourth, sixth and eleventh aspects of the present invention, the above configuration is possible regardless of the type of sheet including a relatively high rigidity sheet such as cardboard while being space-saving, simple configuration and low cost. By the appropriate elastic displacement / deformation of the belt, the sheet can be fed / conveyed to the downstream side in the sheet conveying direction in the second conveying unit at a stable linear velocity while holding the sheet with the belt.

  According to the second and eleventh aspects of the invention, when the belt has a hardness of 40 to 80 degrees and the extension ratio is 4% under the special conditions, the conveying surface of the belt contacting the sheet is the guide member. When the belt bulges in a direction that interferes with the belt, the guide member is arranged at a position away from the conveyance surface so that it does not interfere with the conveyance surface of the belt. Since it becomes possible to expand the selection range of the rate, the degree of freedom of design can be expanded.

  According to the fifth and eleventh aspects of the invention, when the belt hardness is 35 to 85 degrees and the extension ratio is 4%, the belt conveying surface in contact with the sheet is the guide member. When the belt bulges in a direction that interferes with the belt, the guide member is arranged at a position away from the conveyance surface so that it does not interfere with the conveyance surface of the belt. Since it becomes possible to expand the selection range of the rate, the degree of freedom of design can be expanded.

  According to the eighth and eleventh aspects of the invention, by setting the material as the elastic member, the belt can be stably rotated and the sheet can be stably gripped regardless of the sheet type. .

  According to the ninth and eleventh aspects of the invention, with the above configuration, the leading end of the sheet is disposed so as to come into contact with the belt conveyance surface excluding the belt portion held by the belt holding rotation member. The effects of the first, third, fourth, sixth and eleventh aspects are remarkable.

  According to the tenth and eleventh aspects of the invention, the effects of the inventions of the first, third, fourth, sixth and eleventh aspects become remarkable due to the above configuration.

  According to the twelfth aspect of the present invention, as an image forming apparatus having the sheet conveying apparatus according to any one of the first to eleventh aspects, an image forming apparatus having the effects of the above inventions can be realized and provided. it can.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) including the best mode for carrying out the present invention will be described with reference to the drawings. Constituent elements such as members and components having the same function and shape, etc. over the examples, embodiments, modifications, examples, etc. of the sheet conveying device to which the above-mentioned invention of the prior application is applied and the image forming apparatus equipped with the same. Will be omitted after having been described once by assigning the same reference numerals. In order to simplify the drawings and the description, even components that are to be represented in the drawings may be omitted as appropriate without being specifically described in the drawings. When a constituent element such as a published patent gazette is cited and explained as it is, the reference numeral is attached with parentheses to distinguish it from that of each embodiment.

  FIGS. 4 to 10 to be described later including FIGS. 1 to 3 and the like include examples of a sheet conveying apparatus to which the invention of the prior application is applied and an image forming apparatus on which the sheet conveying apparatus is mounted. explain in detail. First, an overall configuration of a copying machine 1 as an example of an image forming apparatus will be described with reference to FIG.

The copying machine 1 is a monochrome copying machine that reads an image from the surface of a document and forms a copy image on recording paper, transfer paper, paper, OHP film, etc. as various sheet-like recording media (hereinafter referred to as “sheets”). is there. The copying machine 1 includes an image forming apparatus main body 2 having an image forming unit that performs a predetermined image forming process based on a read original image, and the image forming apparatus main body 2 mounted thereon. As an example, a sheet feeding device 3 that supplies sheets S one by one, and a document reading device 4 that is mounted on the image forming apparatus main body 2 reads a document image and sends this document image information to the image forming apparatus main body 2. Have.
A paper discharge tray 9 is provided on the upper part of the image forming apparatus main body 2 so as to form a space below the document reading device 4 and discharge and stack the sheets that have passed through the image forming apparatus main body 2. A paper transport path R1 (hereinafter also referred to as “transport path R1”) is formed as a paper transport path (sheet transport path) for moving the paper S from the paper device 3 to the paper discharge tray 9. Most of the transport path R1 extends from the sheet feeding device 3 to the upper part of the image forming apparatus main body 2, and extends in a substantially vertical upward direction, that is, a substantially vertical upward direction with respect to a substantially horizontal line, and the transport path R1. On the top, there are provided sheet conveying means as several sheet conveying means which are configured by a pair of conveying rollers, a pair of rollers, etc. with a predetermined interval corresponding to the minimum size sheet S. Any one of these sheet conveying means is configured to always convey the sheet S on the conveying path R1 by nipping or the like. Further, the sheet feeding device 3 is provided with a sheet conveying device 5 as a sheet conveying device for feeding and conveying the sheets S accommodated in the respective stages of the sheet feeding device 3 to the conveying path R1.

  In the image forming apparatus main body 2, a photosensitive unit 10 as an image forming unit for forming an image and a fixing device 11 are sequentially arranged from the upstream side to the downstream side of the conveyance path R <b> 1. After the photoreceptor unit 10 transfers the generated toner image to the sheet S conveyed from the upstream side to the downstream side on the conveyance path R1, the fixing device 11 transfers the transferred toner image. The sheet S fixed on the sheet S and fixed with the toner image is discharged to a sheet discharge tray 9 disposed at the end of the transport path R1.

The photoconductor unit 10 has a single drum-like photoconductor 10A as an image carrier, and can be rotated to a side plate (not shown) in the image forming apparatus main body 2 around a rotation shaft arranged substantially horizontally. It is supported by. The photoconductor 10A has a known configuration formed in a cylindrical shape with a predetermined diameter. The photosensitive member 10A is stabilized in the rotational direction indicated by an arrow in the drawing when a rotational driving force is transmitted from a driving source such as a motor provided on either the photosensitive unit 10 side or the image forming apparatus main body 2 side. It is driven to rotate at a constant speed.
Around the photoconductor 10A, a developing device 12, a transfer device 13, a photoconductor cleaning device 18, a static eliminator, and a charging device 14 are arranged in the rotation direction indicated by the arrows in the drawing. Within the range of one rotation in the counterclockwise rotation direction, the development position, the transfer position, the cleaning position, the charge removal position, and the charging position are sequentially applied from the upstream to the downstream by each of these devices 12 to 14, respectively. Is set.
Further, a latent image forming position is set between the charging position and the developing position, and exposure is performed to write an invisible latent image corresponding to image information by irradiating the latent image forming position with a predetermined laser beam. The device 47 is disposed obliquely below and slightly away from the photoconductor unit 10. Then, the photoconductor 10A is rotationally driven in a predetermined counterclockwise direction, and each of the devices 12 to 14 and the exposure device 47 perform a cooperative operation in a predetermined manner in synchronization with the rotation of the photoconductor 10A. Thus, a series of image forming processes are executed.

That is, the developing device 12 has an appropriate well-known configuration such as a developing roller that generates a toner brush in which toner particles are erected radially from the surface thereof, and is generated at a predetermined location on the surface of the photoreceptor 10A. The toner particles at the tip of the toner brush are attached to the latent image that moves around the circumference and passes through the developing position with the rotation of 10A, and the invisible latent image is visualized as a monochrome toner image.
The transfer device 13 includes two support rollers 15 and 16 that are opposed to each other with a predetermined spacing in a substantially vertical direction, and a transfer belt 17 that is an endless belt stretched between the support rollers 15 and 16. Then, the toner image on the outer peripheral surface of the photoreceptor 10A is transferred to the sheet S, and the sheet S on which the unfixed toner image is transferred is conveyed to the downstream side of the conveyance path R1. That is, the lower support roller 16 has its portion around which the transfer belt 17 is wound pressed against an approximately right diagonally lower portion of the photoconductor 10A, and the transfer belt 17 is transferred to a location where the surface of the photoconductor 10A and the transfer belt 17 are in contact with each other. The position is set. Further, the upper support roller 15 is disposed in front of the introduction port of the fixing device 11.

The photoconductor cleaning device 18 is a blade material (not shown) configured such that the blade edge at the tip thereof is in contact with the cleaning position on the photoconductor 10A with a predetermined pressure, or the photoconductor is in contact with the cleaning position. It has either or both of the configurations of a rotating brush that rotates following the rotation of 10A, and removes toner, foreign matter, and the like remaining on the surface of the photoreceptor 10A after transfer.
The static eliminator is mainly composed of a lamp capable of emitting light of a predetermined intensity. The static elimination position is irradiated from the lamp to the static elimination position, and the charged state on the surface of the photoreceptor 10A passing through the static elimination position is determined. The surface potential of the photoconductor 10A after being released and passing through the transfer position is returned to the initial state.

The fixing device 11 includes a heating roller 31 having a built-in electric heater as a heat source, and a pressure roller 32 disposed to face the heating roller 31 in a substantially horizontal direction and pressed and urged toward the heating roller 31. When the heating roller 31 is rotationally driven by a driving source such as a motor (not shown), the pressure roller 32 in contact therewith is driven to rotate, and at a place where both the rollers 31 and 32 are in contact, a predetermined heating temperature is set. Thus, a nip portion for fixing the toner image on the paper is formed.
In the figure, reference numeral 20 denotes a toner storage container composed of a toner bottle or the like that stores new or new toner. A toner transport path (not shown) is formed from the toner storage container 20 to the developing device 12. When the developing device 12 consumes its own toner for development and becomes insufficient, new toner is replenished from the toner container 20 to the developing device 12.

  Below the image forming apparatus main body 2 is provided a paper feeding device 3 that can selectively select a paper size (sheet size) automatically or manually by a user according to the size of a document to be read. Yes. That is, the sheet feeding device 3 stores and arranges a plurality of sheet feeding trays 51 and 51 as sheet storing means in multiple stages in the sheet feeding device 3 and feeds each sheet feeding tray 51 and 51 individually. It is configured to be able to be pulled out of the apparatus 3, and the paper for the tray can be set in each paper feed tray 51 and an appropriate number of sheets can be replenished. Each of the paper feed trays 51 and 51 stores and stores a large number of sheets S having different sheet types (sheet types) in various vertical sizes and horizontal directions with respect to various sheet sizes and sheet conveyance directions (sheet conveyance directions). ing.

The document reading device 4 has a reading device main body 4A that forms the framework, and a contact glass 57 is disposed over a predetermined range on the upper surface of the reading device main body 4A. In the reading apparatus main body 4A, reading means for optically reading a document image with a predetermined range on the surface of the contact glass 57 as a scanning target is accommodated. The reading means includes at least the first traveling body 53, the first traveling body 53, and the like. 2 is mainly composed of a traveling body 54, an imaging lens 55, and a reading sensor 56 such as a CCD.
Further, in the document reading device 4, a document pressing plate 58 configured to be openable and closable between a closed position covering the contact glass 57 and an opened open position is provided on the upper surface of the reading device main body 4A. That is, the document pressing plate 58 is formed in a vertical and horizontal dimension larger than that of the contact glass 57, and one end thereof is supported on the upper surface of the reading apparatus main body 4A by a hinge (not shown) so as to be freely opened and closed.

  Based on the configuration described above, the operation of the copying machine 1 will be described. First, when copying a document with the copying machine 1, the user manually opens the document pressing plate 58 of the document reading device 4 from the closed position to the open position, and places and sets the document on the contact glass 57. The document pressing plate 58 is manually operated in the closing direction, and the document set on the contact glass 57 is pressed from above by the document pressing plate 58. By this operation, the original is brought into close contact with the contact glass 57 and spread in a flat shape so that the original surface can be read accurately, and the original is fixed on the glass 57.

  When the user depresses / turns on a start switch installed in an operation screen (not shown) provided in advance in the copying machine 1, the reading operation of the document reading device 4 is immediately started, and a drive mechanism (not shown) The first traveling body 53 and the second traveling body 54 are traveled. Then, the light from the light source of the first traveling body 53 is irradiated toward the document, the reflected light from the document surface is directed to the second traveling body 54, and the reflected light is reflected by the mirror of the second traveling body 54. The image is input to the reading sensor 56 through the imaging lens 55. As a result, the reading sensor 56 photoelectrically converts an image of the document and the like and reads it.

  When the start switch is turned on as described above, the photoconductor 10A of the photoconductor unit 10 starts rotating, and an operation for forming a toner image on the photoconductor 10A based on the read original image. Is started. That is, as the photoconductor 10A is rotated, predetermined portions on the outer peripheral surface of the photoconductor 10A are sequentially arranged between the charging device 14, the exposure device 47, the developing device 12, the transfer device 13, the photoconductor cleaning device 18, and the charge eliminating device. After passing through the respective positions set in step 1, the toner is sequentially charged to a predetermined charged state, a latent image is generated, visualized as a toner image, transferred to the paper S, and the residual toner is removed. The charging state is released, one cycle is completed, and the cycle is predetermined so that a toner image is generated in a predetermined length range of the outer peripheral surface in the rotation direction of the photoconductor 10A according to the image size to be formed. Persisted.

When the start switch is pressed, the operation of the sheet conveying device 5 attached to the sheet feeding stage from the sheet feeding tray 51 of the sheet feeding stage in which the automatically or manually selected sheet S is stored in the sheet feeding apparatus 3 is operated. Thus, one sheet S is conveyed to the conveyance path R1 via a predetermined sheet conveyance path (sheet conveyance path). The sheet S is conveyed by a conveyance roller or the like on the conveyance path R1 in the image forming apparatus main body 2 substantially vertically upward, and the leading edge of the sheet S abuts against the registration roller pair 21 and temporarily stops.
On the other hand, in the case of manual paper feed, the paper S set on the manual feed tray 67 is first fed out by the rotation of the paper feed roller 67A for the manual feed tray, and when a plurality of paper S are stacked and set. The paper is separated into one sheet by the separation rollers 67B and 67C for the manual feed tray, conveyed to the manual sheet feed path R2, and further conveyed from the manual sheet feed path R2 to the conveyance path R1. It hits 21 and stops.
Then, the registration roller pair 21 starts to rotate at an accurate timing according to the relative movement of the toner image on the photoconductor 10A that has been rotationally driven, and sends the temporarily stopped paper S to the transfer position. As a result, the toner image is transferred onto the paper S by the transfer device 13.

  The sheet S to which the unfixed monochrome toner image is transferred in this way is conveyed to the fixing device 11 by the transfer belt 17 of the transfer device 13 that forms a part of the conveying path R1, and passes through the nip portion formed by the fixing device 11. Then, predetermined heat and pressure are applied by the nip portion, whereby the image is fixed on the paper S. The sheet S on which the image is fixed is guided by the switching claw 34 toward the conveyance path R1 reaching the discharge tray 9 and is discharged onto the discharge tray 9 by the discharge rollers 35 to 38. Is stacked. Then, the user can take out the paper stacked on the paper discharge tray 9 from the opening portion on the front side of the apparatus between the paper discharge tray 9 and the document reading device 4.

  Further, when the duplex copy mode is selected by the user's setting input, the sheet S on which the image is fixed on one side is conveyed to the sheet reversing device 42 side by the switching claw 34 and is arranged in the sheet reversing device 42. A plurality of pairs of rollers 66 and a guide member (not shown) are moved back and forth on the reverse conveyance path R3 to reverse the vertical direction of the paper surface, and then the resist is registered from a position positioned in front of the photosensitive unit 10. After returning to the conveyance path R1 via the roller pair 21, the sheet is conveyed on the conveyance path R1 and guided again to the transfer position. This time, after the image is transferred and fixed on the back surface of the sheet S, the discharge rollers 35 to 38 are used. The paper is finally discharged onto the paper discharge tray 9.

(First example)
Next, a characteristic configuration of the sheet conveying apparatus 5 (hereinafter also referred to as “first example”) to which the sheet conveying apparatus according to the invention of the prior application is applied will be described.
As shown in FIGS. 2 and 3, the sheet transport device 5 has a large number of sheets S stacked and accommodated in a predetermined tray (lower in this example) of the paper feed tray 51 in the paper feeder 3 shown in FIG. 1. One sheet S is pulled out from the sheet S, the sheet conveyance direction (sheet conveyance direction) of the drawn sheet S is changed, and the sheet S is fed to the image forming apparatus main body 2 substantially vertically above.

  The sheet conveying device 5 is disposed on the downstream side of the first conveying unit (hereinafter referred to as “first conveying unit”) 6 that conveys the sheet S and the sheet conveying direction (sheet conveying direction) of the first conveying unit 6. A second conveying means (hereinafter referred to as “second conveying means”) 7 for conveying the paper S conveyed by the first conveying means 6 in a paper conveying direction different from the paper conveying direction of the first conveying means 6; Each of the first conveying means 6 and the second conveying means 7 is configured as a nipping and conveying means for nipping and conveying the sheet S by a pair of conveying rotating members, that is, the first conveying means 6 is a feed roller 61. And a reverse roller 62. The second conveying means 7 is composed of two conveying rotating members disposed opposite to each other. The second conveying means 7 includes a grip roller 81, a roller-shaped pulley 83, and a roller-shaped pulley 84. Stretched between The second conveying rotary member pair is composed of two conveying rotary members disposed opposite to the conveying belt 82, and one of the second conveying rotary member pairs is kept in contact with the leading edge of the paper S. However, it is a belt conveying means 8 (movement guiding means) provided with a conveying belt 82 that moves and guides the paper S toward a clamping section (to be described later) of the second conveying means 7, and the conveying belt 82 in the belt conveying means 8. A conveying surface 82a, which is a belt traveling surface formed on the upper surface, is an outer periphery of the first conveying path A as a sheet conveying path (sheet conveying path) formed between the first conveying means 6 and the second conveying means 7. It is characterized by being arranged at a position deviating in the direction.

As described above, the paper conveyance direction of the first conveyance rotation member pair including the feed roller 61 and the reverse roller 62 and the paper conveyance direction of the second conveyance rotation member pair including the grip roller 81 and the conveyance belt 82 are: Different from each other, that is, the sheet conveying direction of the first conveying rotating member pair is set to a substantially horizontal direction which is an upper right diagonal direction in FIGS. 2 and 3, whereas the sheet conveying direction of the second conveying rotating member pair is The direction is set substantially vertically upward. Thus, the first conveyance path A formed between the first conveyance means 6 and the second conveyance means 7 is a curved curvature having a small curvature radius that causes the paper conveyance direction to change rapidly in the first conveyance path A. Forming part.
Here, the respective paper transport directions of the first and second transport means 6 and 7 are strictly expressed as follows. That is, in FIG. 4, the sheet conveying direction of the first conveying means 6 is the rotation center of the feed roller 61, the rotation center of the reverse roller 62, and the center of the nipping portion (nip portion) of the feed roller 61 and the reverse roller 62. Are set in a substantially horizontal direction orthogonal to the center of the nip portion in the line segment connecting the three points.
Similarly, the sheet conveying direction of the second conveying means 7 includes three points: the rotation center of the grip roller 81, the rotation center of the pulley 83, and the center of the gripping portion (nip portion) of the grip roller 81 and the conveying belt 82. It is set in a substantially vertical upward direction perpendicular to the center of the nip portion in the connecting line segment.

  In other words, in the paper transport path formed between the first transport means 6 and the second transport means 7 and configured to change the paper transport direction, the thickness of the paper S constituting and transporting the paper transport path Of the pair of opposing surfaces that define the direction of the direction, the surface on the side where the leading edge of the paper S sent out from the first conveying means 6 abuts is at least the part where the leading edge of the paper S abuts. Thus, a predetermined range from the longitudinal direction of the paper conveyance direction to the second conveyance unit 7 is configured as a conveyance guide surface that continuously and constantly moves in a direction approaching the clamping portion of the second conveyance unit 7. The conveying guide surface is formed by a belt running surface (conveying surface 82a) formed on the conveying belt 82 in the belt conveying means 8. In addition, the range surrounded by the extension line along the paper conveyance direction of the first conveyance means 6 and the extension line along the paper conveyance direction of the second conveyance means 7 is an inner outline, and the other is the outer outline. The conveying surface 82a of the conveying belt 82 used for conveying the sheet formed by the flat belt running surface is disposed at a position deviated from the inner contour in the outer contour direction, and generally intersects the paper traveling direction. Has been extended to.

As shown in FIGS. 3 and 4, the belt conveying means 8 includes a conveying belt 82, a grip roller 81 and a conveying belt 82 for holding the conveying belt 82 so as to be able to travel and winding the conveying belt 82. The roller-like pulley 83 as the first belt holding and rotating member disposed opposite to the nipping portion (nip portion) of the roller, and the sheet conveying direction of the second conveying means 7 facing the pulley 83. And the above-described roller-shaped pulley 84 as the second belt holding and rotating member disposed on the upstream side. In the present example, a single example of the second belt holding and rotating member is shown, but the present invention is not limited to this, and at least one or more may be provided.
In the belt conveyance unit 8, the leading edge of the paper S conveyed by the first conveyance unit 6 abuts on the conveyance surface 82 a of the conveyance belt 82 excluding the conveyance belt 82 portion held by the pulley 83 and the pulley 84. It is important to arrange them so that they are in contact. In this way, the belt is conveyed such that the shaft center of the pulley 84 (center of the pulley shaft 84a) is located above the lower end position of the reverse roller 62 and below the downstream end height of the conveyance guide member 71. By disposing the means 8, the leading edge of the sheet S collides with the belly portion of the conveyance belt 82 (the portion that should be called “effective conveyance surface”), so that the stable elastic displacement of the conveyance belt 82 is stable. A deformed state is obtained, and the state in which the leading end of the sheet S is reliably in contact with the transport surface 82a of the transport belt 82 without being repelled is maintained, and the effects described below can be obtained. it can.
On the other hand, when the leading edge of the paper S is arranged so as to be in contact with (contact with) the conveyor belt 82 held by the pulley 83 and the pulley 84 of the conveyor belt 82, the conveyor belt 82 is connected to the pulley 83. The conveyor belt 82 portion held by the pulley 84 is generally harder than the belly portion of the conveyor belt 82 and is less elastically displaced and deformed. In this case, it is not preferable because it repels or a stable and appropriate elastic displacement / deformation state cannot be obtained. The same applies to each of the examples to which the invention of the prior application described later is applied, and the embodiments, modifications, examples, etc. to which the invention of the present application is applied (hereinafter also referred to simply as “the same”).

Further, as shown in FIG. 4, the belt conveying unit 8 causes the leading edge of the sheet S conveyed by the first conveying unit 6 to enter the conveying surface 82 a of the conveying belt 82 with an acute entry angle θ. It is also important to place them in By arranging the belt conveying means 8 in this way, the leading edge of the sheet S stably contacts the above-described antinode portion of the conveying belt 82, so that the leading edge of the sheet S is surely brought into contact with the conveying surface 82 a of the conveying belt 82. The state of abutting on is maintained, and the effects described below can be obtained.
In the case where the leading edge of the sheet S is arranged so as to enter the conveying surface 82a of the conveying belt 82 with a substantially perpendicular or perpendicular entry angle θ, the leading edge of the sheet S enters the conveying surface 82a of the conveying belt 82. This is not preferable because the contact state becomes unstable, for example, it is bent in a direction opposite to the traveling direction of the conveyor belt 82 or repulsion is caused (the same applies hereinafter).

The paper feed trays 51 of each stage in the paper feed device 3 are formed in a substantially flat box shape with an upper opening, ensuring a planar shape capable of storing the maximum size paper S that can be handled by the copying machine 1. A bottom plate 50 as a sheet stacking unit is provided on the bottom surface. The bottom plate 50 is attached and fixed to a horizontal shaft 50A supported at the base end portion on the left side in FIG. The free end portion is configured to be swingable in the paper feed tray 51 about the shaft 50A.
In addition, a recess having a predetermined shape is formed at the bottom of the paper feed tray 51, and the rising arm 52 is stored in the recess. The ascending arm 52 is fixed to a horizontal shaft 52A that is supported so that the base end portion of the rising arm 52 can rotate within a predetermined angular range within the concave portion, that is, can swing, and the horizontal shaft 52A has a rotation (not shown). When the rotational driving force in an arbitrary rotational direction is transmitted from the driving source and rotated, the ascending arm 52 is driven to swing so as to occupy a predetermined tilted position about the horizontal shaft 52A. As a result, the free end of the raising arm 52 pushes up the bottom plate 50, and the one side periphery of the uppermost surface of the paper S placed on the bottom plate 50 is kept at a predetermined height position.

As described above, the paper feed tray 51 loads and stores the sheets S on the bottom plate 50 and raises the stacked sheets S by raising and tilting the free end portion on the right end side of the bottom plate 50 in the drawing. Even when the sheets S are fed one by one and the number of stacked sheets decreases, the uppermost surface is maintained at a predetermined height.
As described above, the paper feed tray 51 is configured to be attachable / detachable / removable with respect to the main body of the paper feeder 3. That is, the paper feed tray 51 is inserted into the main body of the paper feeding device 3 as shown in FIG. It is configured to be able to selectively occupy the separation position where the paper S can be replenished or the size of the paper S can be exchanged by being pulled out / removed to the front side.
Further, at least the first transport unit 6, the second transport unit 7, and the paper transport path (transport path) disposed between the first transport unit 6 and the second transport unit 7 are when the paper feed tray 51 is pulled out. Left in the body. Therefore, in this example, it is an in-body discharge type image forming apparatus, but by providing the movement guide means, the above-mentioned conveyance path can be conveyed with the same curvature as the conventional one or less. Without increasing the size, the advantage of the in-body discharge type can be prevented from being reduced.

The pickup roller 60 is rotatably supported by the housing 80 that forms the outer shape of the main body of the paper feeding device 3 so as to contact the uppermost surface of the paper S that has been raised to a predetermined height. A paper feed separation mechanism for separating and feeding the paper S into a single sheet is positioned on an extension line along the drawing direction of the paper S by the pickup roller 60. This paper feed separation mechanism is reverse to the feed roller 61. The roller 62 is configured to form a nip portion that is in contact with a predetermined pressure.
As shown in detail in FIG. 3, the pickup roller 60 is a well-known one that is integrally fixed around a shaft 60a that is integrally formed with a core metal (not shown), and is rotatable with the shaft 60a. A one-way clutch (not shown) is provided between the shaft 60a and the metal core, and is supported so as to rotate freely with respect to the shaft 60a when not driven. A soft high-friction material such as rubber having a high friction coefficient with respect to the paper S is used for the outer peripheral portion including the outer peripheral surface of the pickup roller 60 so that the pick-up roller 60 can be easily picked when contacting the paper S. In addition, on the outer peripheral surface portion of the pickup roller 60, there may be a case where a substantially saw-tooth shaped protrusion is formed on the entire circumference in order to increase the frictional resistance as appropriate.

  In this example, for example, an FRR (Feed Reverse Roller) paper feeding method, which is a reverse separation method, is adopted as a paper feeding method (sheet feeding method) that separates and feeds stacked paper S into one sheet without double feeding. is doing. That is, when two or more sheets S are pulled out by the pickup roller 60, the sheet S is separated into one sheet S in contact with the feed roller 61 and other sheets S in contact with the reverse roller 62, The feed roller 61 advances and feeds one sheet S as it is in the sheet conveying direction, while the reverse roller 62 advances another sheet in the direction opposite to the sheet conveying direction to return to the original stacked position. In addition, the reverse roller 62 is configured not to interfere with the sheet conveyance by the feed roller 61.

More specifically, the sheet feed separation mechanism using the FRR sheet feed method as the sheet separation mechanism is in contact with a feed roller 61 that is rotationally driven in a forward direction that advances in the sheet conveyance direction, and a lower side of the feed roller 61. , A reverse roller 62 that is rotated in reverse by a rotational driving force transmitted in the reverse rotation direction via a torque limiter is provided, and the feed roller 61 is in contact with the uppermost sheet S on the bottom plate 50, The reverse roller 62 is in contact with the lower surface of the paper S in contact with the feed roller 61 regardless of whether two or more sheets are present.
The feed roller 61 is integrally fixed around a shaft 61a formed integrally with a core metal (not shown) and can be rotated together with the shaft 61a, or the same support method as that of the pickup roller 60 can be used. Sometimes. In the outer peripheral portion including the outer peripheral surface of the feed roller 61, a rubber having a high coefficient of friction with respect to the paper S so that it can be easily sent out in the paper transport direction when it contacts the paper S, like the pickup roller 60. Such a soft high friction material is used. Further, the outer peripheral surface portion of the feed roller 61 may be formed with substantially saw-tooth shaped protrusions on the entire circumference in order to increase the frictional resistance as appropriate.
The reverse roller 62 is formed integrally with a metal core (not shown), and is rotatably supported by the housing 80 together with the reverse roller drive shaft 62a via the torque limiter.

In the FRR sheet feeding method, a weak torque in the reverse rotation direction with respect to the feed roller 61 is applied to the reverse roller 62 via a torque limiter (not shown). Accordingly, when the reverse roller 62 is in contact with the feed roller 61 or when one sheet S enters between the rollers 61 and 62, the reverse roller 62 rotates with the feed roller 61. That is, by the action of the torque limiter, for example, the reverse roller 62 slips with respect to the reverse roller drive shaft, and similarly to the feed roller 61, the reverse roller 62 rotates in the forward direction that advances in the paper feeding direction. On the other hand, when the feed roller 61 is separated or when two or more sheets S enter between the rollers 61 and 62, the reverse roller 62 rotates in the reverse direction. For this reason, when the multi-feed paper S enters, other paper S in contact with the reverse roller 62 other than one paper S in contact with the feed roller 61 which is the uppermost paper S is upstream in the paper transport direction. Thus, the double feeding of the paper S is prevented.
Accordingly, the conveyance force supplied from the reverse roller 62 to the sheet S in contact with the reverse roller 62 is sufficient to ensure the conveyance force in the reverse direction sufficient to return the sheet S to the original stacking position. The conveying force supplied to the sheet S from the feed roller 61 for advancing S in the forward direction is set to a predetermined value so as not to prevent the sheet conveyance in the forward direction by the feed roller 61. For this reason, the so-called transport force supplied from the feed roller 61 to the paper S is reduced by the reverse transport force from the reverse roller 62.

  In the figure, reference numeral 65 denotes an idler gear coupled to a drive shaft that outputs a rotational driving force from a drive source provided on the main body side of the sheet feeding device 3, and the sheet feeding device is engaged by meshing between the gears or belt transmission. 3 is distributed and transmitted to the pickup roller 60 and the feed roller 61 so that the pickup roller 60 and the feed roller 61 are respectively rotated at a predetermined speed.

A grip roller 81 which is the other transport rotation member of the second transport rotation member pair in the second transport means 7 is disposed obliquely above the feed roller 61 via a rotation drive shaft 81 a formed integrally with the grip roller 81. The housing 80 is rotatably supported and arranged. As with the feed roller 61, the outer peripheral portion including the outer peripheral surface of the grip roller 81 has a high friction coefficient with respect to the paper S so that it can be easily sent out in the paper transport direction. Soft high friction materials such as rubber are used.
In the vicinity of the grip roller 81, the pulley 83 is rotatably supported by the housing 80 so as to be in contact with the outer peripheral surface of the roller 81 via the conveying belt 82 and faces the grip roller 81 in the horizontal direction. Is arranged.
The pulley 83 is formed integrally with the pulley shaft 83a and is rotatably supported by the housing 80 together with the pulley shaft 83a. Below the pulley 83 diagonally to the left, the pulley 84 described above that is rotatably supported by the housing 80 is disposed. The pulley 84 is formed integrally with the pulley shaft 84a and is rotatably supported by the housing 80 together with the pulley shaft 84a. The pulleys 83 and 84 have a function as a belt holding and rotating member that supports and holds the conveyance belt 82 so as to run and rotate.

The arrangement of the belt conveying means 8 is not limited to the arrangement state described above, and may be as follows. That is, in FIG. 3, reference numeral 79 shown with parentheses indicates an open / close guide configured to be openable and closable with respect to the housing 80 as a part of the main body of the sheet conveying device 5. The open / close guide 79 is integrated (unitized) with a transport guide member 72 and a belt transport unit 8 which will be described later, and is configured as an open / close unit, such as a first transport path A and a vertical transport path extending substantially vertically upward. In order to make it easier for the user to handle paper jams, jams, etc., the conveyor belt 82 can be brought into and out of contact with the grip roller 81 around a hinge fulcrum shaft (not shown) below the housing 80. It is configured to be openable and closable.
When such an opening / closing guide 79 is provided, the pulley 83 and the pulley 84 are rotatably supported on the opening / closing guide 79 side together with the pulley shafts 83a and 84a. Note that the opening / closing guide 79 shown in FIG. 3 and the like is compared with the opening / closing guide 79A shown in FIG. Instead of the belt conveying means 8A, a conveying belt 82 is provided that extends or is divided along the sheet width direction so as to be in contact with at least the entire area or both side edges of the sheet S in the sheet width direction. The main difference is that the belt conveying means 8 is arranged.

Although the conveyance belt 82 is partially described above, it is an endless belt and is stretched between the pulleys 83 and 84. The distance between the shafts of the pulleys 83 and 84 is set in advance. The linear belt running surface (conveying surface 82a) of the conveying belt 82 formed between the pulleys 83 and 84 is disposed at a position where the leading edge of the sheet S sent out by the first conveying means 6 always comes into contact. As described above, the outer peripheral surface of the conveyor belt 82 wound around the outer peripheral surface of the pulley 83 is in direct contact with the outer peripheral surface of the grip roller 81 with a predetermined pressure, and a clamping portion (nip portion) is formed at this contact portion. Has been.
The conveyor belt 82 is formed of, for example, a rubber member that is an elastic member, and the surface thereof is made of a material of the belt itself or subjected to an appropriate surface treatment to the paper S (sheet) to be used. A predetermined coefficient of friction is set. That is, the conveyance belt 82 faces the sheet S and contacts the sheet surface, and the belt surface as the conveyance surface avoids a sliding contact between the sheet surface and the belt surface, so that the belt surface extends to the sheet surface. A coefficient of friction that can reliably transmit the transport driving force is set.

  Further, the conveyance belt 82 has a belt width in the sheet width direction orthogonal to the sheet conveyance direction, which is at least substantially the same as the maximum sheet width to be conveyed. That is, as the belt width of the conveying belt 82, at least a belt width equal to or larger than the maximum sheet width to be conveyed is set and secured. Similarly, the pulleys 83 and 84 on which the conveying belt 82 is stretched and the grip roller 81 facing and contacting the belt have pulleys and roller lengths in the paper width direction (axial longitudinal direction) longer than the belt width. Is formed. Therefore, the sheet S sent out from the first conveying means 6 always comes into contact with the conveying belt 82 over the entire width of the sheet, and the contact area between the two can be ensured as much as possible. Accordingly, the propulsive force supplied to the sheet S from the conveying belt 82 that is always moved in the sheet conveying direction, that is, the conveying propulsive force that advances the sheet S in the conveying direction, also has the maximum possible force from the conveying belt 82. It can be transmitted to the paper S.

A rotational drive source such as an electric motor provided exclusively for rotational driving of the grip roller 81 is connected to a rotational driving shaft 81a of the grip roller 81 via a driving force transmission means (not shown) such as a gear or a belt. They are connected (for example, see FIG. 11 and FIG. 12 showing an embodiment described later). The grip roller 81 is rotationally driven by transmitting a rotational driving force at a predetermined rotational speed from the rotational driving source via the driving force transmitting means. Thus, the grip roller 81 is a drive roller, while the conveyor belt 82 in contact with the grip roller 81 and the pulley 83 that supports the contact portion of the conveyor belt 82 from the inside of the belt are grips as a drive roller. A driven belt driven by a belt is driven by the rotation of the roller 81, and a driven roller is driven to rotate through the driven belt. Of course, the pulley 84 is also a driven roller that is rotationally driven via the driven belt.
If it is not necessary to have the same effect as that of the embodiments described later with reference to FIGS. 11 and 12, for example, the drive system for driving the grip roller 81 is removed from the drive mechanism 22 to remove the grip roller. 81 may be a driven side, and the conveyance belt 82 side may be driven by a drive mechanism (not shown).

2 and 3, reference numeral 70 denotes a conveyance guide member that is provided at a position on the inner side of the sheet conveyance device 5 and has a curved and fixed guide surface 70 a that protrudes substantially downward and contacts the sheet S. Reference numeral 71 denotes a conveyance guide member provided at a position on the outer side of the sheet conveyance device 5. The transport guide member 71 has a guide surface 71 a that is curved and fixed in a concave shape corresponding to the transport guide member 70, and is disposed facing the guide surface 70 a of the transport guide member 70 with a predetermined gap. . Thus, the first conveyance path A is formed between the first conveyance means 6 and the second conveyance means 7 by the conveyance guide member 70, the conveyance guide member 71 and the conveyance belt 82 facing the conveyance guide member 70. Has been.
2 and 3, 72 is a conveyance guide member provided at a position on the outer side of the vertical conveyance path approximately vertically upward from the second conveyance means 7, and 73 is a feed from the paper feed tray 51. This is a conveyance guide member that forms a sheet conveyance path to the nipping portion (nip portion) between the roller 61 and the reverse roller 62 and that has an introduction port for guiding and entering the sheet S in the nip portion. The conveyance guide member 70 is a curved surface that bulges substantially downward (on the conveyance guide member 71 side provided on the outer wall) across the line connecting the nip portions of the first conveyance means 6 and the second conveyance means 7. (Guide surface 70a) is provided, and the degree of bulge is set such that the sheet S is gently curved so that the leading edge of the sheet S always reaches the belt conveyance surface.

  In FIG. 1, the upper apparatus configuration of the sheet feeding device 3 is an apparatus configured by conventional means. Compared with the lower apparatus configuration described above, the sheet conveyance apparatus 5 ′ replaced with the sheet conveyance apparatus 5. The only difference is the use of. The sheet conveying apparatus 5 ′ is different from the sheet conveying apparatus 5 only in that the second conveying means 7 ′ is used instead of the second conveying means 7. Compared with the second conveyance means 7, the second conveyance means 7 ′ has a grip roller 81 as a second conveyance rotation member pair and a roller that is driven and rotated (substantially the same size and shape as the pulley 83). Only) is different. In the upper paper feed tray 51 and the paper transport device 5 ′, plain paper or the like, which is the paper S having relatively low rigidity, is used except for the paper S (sheet) having relatively high rigidity such as thick paper and envelopes.

Next, a paper feeding operation from a predetermined stage in the paper feeding device 3 and a transporting operation of the paper transporting device 5 started in conjunction with the paper feeding operation will be described.
As shown in FIG. 2, the sheets S stacked on the bottom plate 50 are lifted so that the uppermost surface thereof has a predetermined height by the swinging and lifting operation of the lifting arm 52. The uppermost sheet S is pulled out and conveyed to a sheet feeding / separating mechanism including a feed roller 61 and a reverse roller 62. In the sheet feeding / separating mechanism, only the uppermost sheet is separated by the cooperative action of the feed roller 61 and the reverse roller 62, and the separated sheet S is moved to the downstream side of the sheet conveying path. Further, as shown in FIG. 2, the leading edge of the sheet S is guided and moved by traveling in the direction of the arrow of the conveyance belt 82 while contacting the belt conveyance surface of the conveyance belt 82, and the grip roller 81 and the conveyance belt 82 are moved. When reaching the nip portion, the sheet S is conveyed by being vertically conveyed while being nipped and conveyed by the grip roller 81 and the conveying belt 82, and finally the sheet S is sent out in a vertical posture.

More specifically, the leading edge of the sheet S that is nipped between the feed roller 61 and the reverse roller 62 and fed out from the nip portion first reaches the belt conveyance surface of the conveyance belt 82 as shown in FIG. And touch. Then, as shown in FIG. 3, the conveyance surface 82a is gradually curved from the leading end side of the sheet S as the conveyance surface 82a moves in the direction of the sheet conveyance due to the traveling of the conveyance belt 82 in the direction of arrow a, and this curve progresses. Accordingly, the contact area between the belt conveyance surface and the paper surface is enlarged. Therefore, even if the paper S is a highly rigid paper, a sufficient transport driving force for advancing the paper S in the transport direction from the belt transport surface to the paper surface can be applied. In this way, the belt conveyance means 8 provides a shortage from the conveyance resistance generated when the highly rigid paper S is curved and conveyed more deeply by the conveyance driving force applied from the first conveyance means 6. This is given to the paper S to be sufficiently compensated. Therefore, it is possible to prevent at least the occurrence of poor conveyance of the paper S between the first and second conveying means 6 and 7 and prevent the paper S from occurring. Nip).
On the other hand, the conveyance surface 82a of the conveyance belt 81 extends continuously as it is to the nipping portion (nip portion) of the second conveyance means 7, so that the leading edge of the sheet S in contact with the belt conveyance surface is reliably and smoothly stabilized. Then, it reaches the clamping part. In other words, first, even the highly rigid paper S is conveyed by the first conveying means 6 while being gently curved so that the leading edge always comes into contact with the belt conveying surface, and the leading edge of the paper S is the belt conveying surface. The leading edge of the sheet S is moved to the second sheet after the second sheet conveying propulsion force that advances in the sheet conveying direction from the belt conveying surface to the sheet S by the active conveying guide action by the belt conveying surface. The sheet S is bent more deeply so as to reach the holding portion of the conveying means 7.

  After the leading edge of the paper S reaches the second transport means 7 and the paper S is nipped and transported by the first transport means 6 and the second transport means 7, the transport means 6 and 7 are sufficient. Since a strong transport force acts on the paper S, the smooth transport of the highly rigid paper S can be continued. Further, even if the rear end of the sheet S is detached from the first conveying unit 6 and the conveying force from the first conveying unit 6 cannot be obtained, the holding portion of the second conveying unit 7 on the sheet S is moved to the rear end side. Depending on the contact state of the belt conveyance surface, the conveyance driving force is replenished from the belt conveyance surface to the paper surface again, and the degree of curvature of the paper S is gradually reduced, so that the paper conveyance can be continued. it can. As a result, as the paper transport device 5, the paper S received by the first transport means 6 is reliably and stably transferred from the second transport means 7 to the downstream paper transport path regardless of the rigidity of the paper S. Can be sent out.

As described above, the belt conveyance unit 8 is disposed in the outer direction of the first conveyance path A formed between the first conveyance unit 6 and the second conveyance unit 7 and maintains a state in contact with the leading edge of the paper S. However, it has a function as a movement guide means for moving and guiding the paper S toward the second transport means 7.
In this example, the belt conveyance unit 8 as the movement guide unit moves and guides the conveyance direction of the sheet S by changing the conveyance direction of the sheet S in the direction toward the nipping portion (nip portion) of the second conveyance unit 7 by the conveyance belt 82. It also has a function.

  Next, Reference Example 1 (hereinafter simply referred to as “Example 1”) according to the invention of the prior application will be described. The basic configuration and specifications are the same as those of the paper feeding device 3 having the paper conveying device 5 shown in FIGS. 1 to 3, and only a paper feeding device of “Imagio Neo453” manufactured by Ricoh Co., Ltd. is modified for testing. Machine (shown as “belt system” in Table 1) and a conventional paper conveying device (in FIGS. 1 to 3), the conveying rotating member facing the grip roller 81 is a roller-like pulley 83, and the conveying belt 82 and "Imagio" manufactured by Ricoh Co., Ltd., which is equipped with a paper feeder provided with a roller-like pulley 84 and having a paper feed device 5 'shown in the paper feeder 3 shown in FIG. Using a Neo453 "copying machine (shown as" conventional system "in Table 1), a comparative test on the paper feeding and conveying state (paper passing state) was conducted.

In the belt system, details of the belt conveying means 8 used in the comparative test and the main members around it (including the conventional system) are as follows.
Material of conveyor belt 82: Ethylene / propylene rubber (EPDM)
Conveyance belt 82 hardness: JIS K6253 A type 40 degrees Friction coefficient of conveyance belt 82 to paper: 2.6
Conveying belt 82 thickness (wall thickness): 1.5 mm
Pulley 83 diameter: 13 mm
Pulley 84 diameter: 7 mm
Spacing between pulleys 83 and 84: 13 mm (distance between pulley shafts 83a and 84a)
Expansion rate of the conveyor belt 82: 7%
Diameter of each roller 60, 61, 62, 81: All 20mm

  As a basic test condition, the weight of the paper (metric basis weight) is used as a substitute value for the strength of the paper (stiffness: stiffness). At a relative humidity of 50%, the sheets were fed from the same tray in the copying machine. Then, with the test conditions described below with reference to FIG. 4, a test for examining the variation (variation) in the conveyance time of each paper type was performed. FIG. 5 shows a test result of the variation in the conveyance time, and Table 1 shows a summary of the sheet passing state based on the test result of FIG.

  In FIG. 4, 88 is a paper feed sensor that detects the leading edge of the paper S picked up by the pickup roller 60, and 89 is a second conveying means 7 (belt system) or a grip roller 81 and a roller-like pulley 83. A vertical conveyance sensor for detecting the leading edge of a sheet conveyed by a pair (conventional method) is shown. The paper feed sensor 88 and the vertical conveyance sensor 89 are each composed of a reflective photosensor.

Further, the conveyance path length between the attachment / arrangement of the paper feed sensor 88 and the vertical conveyance sensor 89: the sheet conveyance distance (sheet conveyance distance) was set to a constant 57 mm for both the belt method and the conventional method as follows. That is, the conveyance path length from the arrangement portion of the paper feed sensor 88 to the nip portion of the feed roller 61 and the reverse roller 62 is 10 mm, and the nip portion of the second conveyance means 7 from the nip portion of the feed roller 61 and the reverse roller 62 ( Belt path), or the conveyance path length from the nip portion between the feed roller 61 and the reverse roller 62 to the nip portion between the grip roller 81 and the roller pulley 83 (conventional method) is the same 38 mm, The conveyance path length from the nip part (belt system) to the arrangement part of the vertical conveyance sensor 89 or from the nip part (conventional system) between the grip roller 81 and the roller pulley 83 to the arrangement part of the vertical conveyance sensor 89 is 9 mm. The total transport path length is 57 mm.
The radius of curvature at the center of the curved paper conveyance path (first conveyance path A) between the first conveyance means 6 and the second conveyance means 7 of the paper conveyance device 5 is constant about 20 mm in both the conventional method and the belt method. Carried out.

  In both the conventional method and the belt method, the pick-up pressure (feed pressure) by the pick-up roller 60 is changed to two types of 1.1N and 2.2N, and the driving-side feed roller 61 and the driving-side grip are changed. Both the linear speeds of the rollers 81 are the same 154 mm / s, and the arrival time of the leading edge of the paper transported through the transport path length 57 mm from the paper feed sensor 88 to the vertical transport sensor 89 is changed to five paper types, respectively. The graph of FIG. 5 shows the variation result of the paper type conveyance time measured by the oscilloscope.

From the test results in FIG. 5, when the metric basis weight is 256 g / m ² or more as the paper type, the conveyance time is long and the paper slip is large in the conventional method, whereas in the belt method of the present invention, the conveyance time is not so long. It turned out that the slip of the paper was small without becoming long. Further, it was found that the conveyance force decreases when the pickup pressure is reduced, but in the case of the belt system of the present invention, even if the pickup pressure is reduced, the conveyance time is not significantly affected. Therefore, when the belt system of the present invention is adopted, the pickup pressure can be reduced, so that the power of the drive motor can be reduced. As a result, the apparatus can be reduced in size.

Next, Table 1 that summarizes the sheet passing state based on the test results of FIG. 5 will be described.
Here, “metric basis weight” corresponds to the weight of one sheet of paper per square meter in grams when displaying the weight of paper or paperboard (paper). In general, a paper having a small basis weight is “light paper” or “thin paper”, and a paper having a large basis weight is “heavy paper” or “thick paper”.
In the test results in Table 1, “good paper passing” indicated by a circle means that the paper feed sensor 88 was turned on and reached the vertical conveyance sensor 89 within a predetermined time after the leading edge of the paper (sheet) was detected. That is, “impossible to pass paper”, which is indicated by an X mark, indicates that the conveyance is good and the vertical conveyance sensor 89 is reached within a predetermined time after the paper feed sensor 88 is turned on and the leading edge of the paper is detected. This indicates that there was no conveyance, that is, a conveyance failure.

From the test results in Table 1, when the metric basis weight is 256 g / m ² or more as the paper type, the conventional method could not pass the paper, whereas the belt method according to the present invention shown in FIGS. All the papers passed. Thereby, the remarkable effect of the belt system according to the present invention was recognized.
According to the comparative observation of the sheet passing / conveying state, when the metric basis weight is 256 g / m ² or more in the conventional method, the sheet becomes stiff and difficult to bend along the curved sheet conveying path. 1 to 4, it was found that the leading edge of the sheet hits a roller-like pulley 83 that is in contact with the grip roller 81.
In addition, as a paper type, a paper having a metric basis weight of 256 g / m ² or more was subjected to a comparative observation of a sheet passing / conveying state using a paper whose surface portion was coated and a paper which was not coated. However, significant differences other than the test results in Table 1 were not recognized.

From the observation results of the paper conveyance process in Example 1 described above, the following was found. That is, when the highly rigid paper S having a metric basis weight of 256 g / m ² or more is transported from the first transport unit 6 to the transport surface 82a of the transport belt 82 in the belt transport unit 8 via the first transport path A. Because of the high straightness transportability of the highly rigid paper S, the various guide members constituting the first transport path A are changed to simple shapes that reduce the transport load resistance or the various guide members are changed. It turns out that it is possible to make it completely unnecessary.
Therefore, in the case of a sheet conveying apparatus that conveys using only the sheet S having relatively high rigidity, the essential components are the first conveying means 6, the second conveying means 7, the first and The second transport unit is disposed in the outer direction of the first transport path A (in this case, no guide member is formed) formed between the second transport units 6 and 7 and maintains a state in contact with the leading edge of the sheet S. Belt conveying means 8 (movement guiding means) for moving and guiding the paper S toward the paper 7.
From the above, the various guide members forming the first transport path A have relatively low rigidity, for example, when the paper S such as plain paper or PPC is transported, the straightness of the paper S with low rigidity is weak. It can be said that it is necessary to compensate for the straightness as compared with the paper S having relatively high rigidity such as thick paper, and to guide and guide it to the transport surface 82a of the transport belt 82. In other words, the first transport path is used in order to make the leading edge of the paper S abut on the antinode portion of the transport surface 82a of the transport belt 82 to compensate for the decrease in straightness as the rigidity of the paper S decreases. It can be said that it is necessary to set the shape of the guide surfaces of the various guide members forming A.
In other words, as the sheet S having higher rigidity (the sheet S having a larger metric basis weight) is used, the various guides used when configuring the sheet conveyance path of the curvature portion having the relatively small curvature radius described above. It becomes possible to give a degree of freedom to the design of the shape and arrangement of the members.
The material of the conveyor belt 82 is not limited to that used in the comparative test, and may be, for example, chloroprene rubber, urethane rubber, or silicon rubber. The rubber hardness of the conveyor belt 82 may be JIS K6253 A type 40 to 60 degrees.

  As described above, according to the paper conveyance device 5 and the copying machine 1 having the same shown in FIGS. 1 to 4, the paper type compatibility is achieved with a simple and low-cost device configuration while being compact and space-saving. It is possible to provide a sheet conveying apparatus and an image forming apparatus excellent in the above. In other words, basically, the conveyor belt is wound around the existing roller that constitutes the second conveying means, and the belt conveying means 8 is newly provided and added, and a dedicated drive source for the belt conveying means 8 is also provided. The sheet conveying device and the image forming apparatus can be realized at a low cost because of the extremely simple configuration.

  In the conventional configuration, the conveyance resistance due to the contact of the sheet with the conveyance guide member 70 is large, or the rigidity is high due to the conveyance load in the first conveyance path A from the first conveyance unit 6 to the second conveyance unit 7. In contrast to the paper type, which causes a conveyance failure, the paper conveyance device 5 can cope with a high-rigidity paper type and is a paper conveyance device with excellent paper type characteristics. That is, in the conventional configuration, since the fixing member is merely arranged for guiding the paper, the speed difference between the transported paper that is a moving body and the fixed guide member is fundamentally different. The sheet conveyance device 5 and the copying machine 1 not only eliminates the conveyance resistance but always eliminates the conveyance resistance and positively advances the sheet downstream. It is possible to guide while applying a conveyance driving force (or, by adding a conveyance force by the second conveyance means 7 to a conveyance force by the first conveyance means 6, the first conveyance means 6 to the second conveyance means 7 Since it is possible to counter the transport load in the first transport path A, the sheet can be advanced downstream). That is, in the paper transport device 5, the frictional resistance generated between the paper S and the transport belt 82 is not a resistance that hinders the transport of the paper S, but a negative resistance for applying a transport driving force to the paper S. Become. In other words, it is not converted to a resistance that acts to prevent the conveyance of the paper S, but is converted to a preferable negative resistance that acts to give a conveyance driving force to the paper S.

In addition, in the transport direction in which the paper S is transported, after the leading edge of the paper S abuts the running surface (transport surface) of the transport belt 82, the difference in the degree of rigidity depending on the paper type as the transport progresses. However, since the leading end surface of the sheet S is conveyed so as to gradually overlap the traveling surface of the conveying belt 82, the area of the sheet surface in contact with the belt traveling surface gradually increases. For this reason, as the contact area increases, the resistance force between the two can be increased, and a larger transport driving force for advancing the paper S in the transport direction can be supplied from the transport belt 82 to the paper S. As a result, the traveling direction of the sheet S is changed toward the nip portion between the grip roller 81 and the conveyance belt 82. In other words, the force acting as the conveyance driving force transmitted from the running surface (conveyance surface) of the conveyance belt 82 to the sheet surface is steadily increased.
Therefore, even if the rigidity of the sheet S is high, the sheet S is surely directed toward the sandwiching portion of the second transporting means while overcoming this rigidity and appropriately deforming or curving the sheet S in the thickness direction. And can be transported stably. As described above, since the main cause of the conveyance failure due to the high rigidity of the sheet S can be dealt with, the sheet conveyance after the leading edge of the sheet S reaches the clamping portion of the second conveying means is reliably and stably performed. It can last. As a result, the paper transport device can cope with a wide variety of paper types, the transport capability can be expanded, and high paper transport performance can be obtained.

(Modification of the first example)
FIG. 6 shows a modification of the first example to which the invention of the prior application is applied.
As shown in FIG. 6 (a), one of the opposed roller pairs of the first conveying means 6 arranged on the upstream side may be the belt conveying means 8, and as shown in FIG. Of the pair of rollers in contact with each other in the first conveying means 6 and the second conveying means 7, one of both sides may be the belt conveying means 8 and 8 ', and further, as shown in FIG. As a moving guide means (moving guide) that substitutes for either one of the roller pair of the first conveying means 6 arranged in the side or one of the roller pair of the second conveying means 7 arranged on the downstream side, these A separate and independent belt conveying means 8 may be provided between the two roller pairs.

In the belt conveying means 8 in the modified example shown in the lower side of FIGS. 6A and 6B, for example, the separation action of the reverse roller 62 (counterclockwise rotation for returning the paper) is affected. The reverse roller 62 is divided into a skewered shape in the axial direction so that the reverse roller 62 is provided, and a roller bearing or the like (not shown) is provided on the outer peripheral side of the shaft between the divided reverse rollers 62 (the portion where the reverse roller 62 is not provided). In addition, by providing a skewer roller pulley (not shown) having an outer diameter slightly smaller than the outer diameter of the reverse roller 62, the conveyance belt 82 is driven to rotate and rotate in the clockwise direction to convey the sheet. What is necessary is just to convey to the 2nd conveyance means 7 and belt conveyance means 8 'of the downstream side. At the nip portion between the feed roller 61 and the reverse roller 62, the conveying belt 82 is provided one step lower than the outer peripheral surface of the reverse roller 62 so as not to form the nip portion. Thus, after the sheet is fed out while being separated into one sheet at the nip portion between the feed roller 61 and the reverse roller 62, the above-described operation of the conveying belt 82 may be exhibited.
Therefore, any of the above-described modified examples can obtain at least the same effects as the first example described above.

(Second example)
A second example to which the invention of the prior application is applied will be described with reference to FIGS. The same components and members as those of the sheet conveying device 5 shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted or simplified. Although not specifically described, the configuration not described in this example, that is, the sheet conveying apparatus and other configurations and the operation thereof are the same as those of the sheet conveying apparatus 5 of the first example and the first embodiment shown in FIGS. is there.

  The sheet conveying apparatus 5 shown in FIGS. 7 to 9 is a first conveying unit 5 formed between the first conveying means 6 and the second conveying means 7 as compared with the sheet conveying apparatus 5 shown in FIGS. In addition to the first conveyance path A serving as the sheet conveyance path, another independent second sheet conveyance path formed from the upstream of the second conveyance means 7 to the second conveyance means 7 and different from the first conveyance path A The point having the second transport path B as the first, the first transport path A and the second transport path B merge at the upstream of the second transport means 7 (hereinafter referred to as “joining transport path” or “joining section”) And the other belt conveying means 8 of the second conveyance rotating member pair is disposed so as to be out of the outline direction of the merged conveyance path of the first and second conveyance paths A and B. Mainly different. The sheet conveying apparatus 5 shown in FIGS. 7 to 9 is the same as the sheet conveying apparatus 5 shown in FIGS. 1 to 4 except for the differences.

  In other words, the belt conveying means 8 is configured such that one of the pair of roller-like pulleys 83, 84 around which the conveying belt 82 is stretched is separated from the pulley 83 by a predetermined distance to be freely rotatable to the housing 80. As a result, the belt conveyance surface is formed as a surface in the outline direction of the second conveyance path B. Therefore, the leading surface of the sheet S conveyed on the first conveying path A by the first conveying means 6 always comes into contact with the conveying surface 82a of the conveying belt 82, and on the second conveying path B by an unillustrated conveying means. This prevents the conveyed paper S from reaching the second transport means 7.

Next, the conveying operation of the sheet conveying device 5 shown in FIGS. 7 to 9 will be described. Since the paper S is fed out and transported from the state of being horizontally stacked in the paper feed tray 51, the paper transport direction in the paper feed separation mechanism of the first transport means 6 is substantially horizontal, but thereafter it is positioned upward. In order to convey the image forming apparatus main body 2 to the image forming unit 2, it is necessary to convey the sheet S in a substantially vertical upward direction orthogonal to the substantially horizontal direction.
Therefore, as shown in FIG. 8, after the sheets S are separated one by one by the sheet feeding / separating mechanism, one sheet S is conveyed with a gentle bend so that the conveyance resistance can be reduced, and the leading end of the sheet S is conveyed. 82 abuts.
Since the conveyor belt 82 travels in a substantially vertical direction (substantially above) indicated by an arrow a in FIG. 8, the leading edge of the sheet S that is in contact with the conveyor belt 82 is As shown in FIG. 9, it is conveyed to the clamping part (nip part) between the grip roller 81 and the conveyor belt 82, and is clamped and conveyed to the downstream side in the substantially vertical direction by the pair of the grip roller 81 and the conveyor belt 82. . At this time, as described above, the sheet S is subjected to the conveyance propulsion force that is transmitted from the conveyance belt 82 in the conveyance direction and acts toward the nip portion between the grip roller 81 and the conveyance belt 82 by the conveyance belt 82. Therefore, even the highly rigid paper S can be stably conveyed without causing a conveyance failure.

  As described above, according to the paper transport device 5 shown in FIGS. 7 to 9, the paper transport device having the merging transport path is the same as the paper transport device 5 described with reference to FIGS. 1 to 4. Effects, that is, high-stiffness paper such as cardboard can be stably conveyed, has excellent paper type compatibility, and has at least two or more conveyance paths such as first and second conveyance paths A and B. The paper conveying apparatus can be applied in correspondence with the developed paper conveying apparatus, and the application range can be expanded, that is, the paper conveying apparatus excellent in model compatibility can be obtained.

  The second example is not limited to the example in which the belt conveying unit 8 is configured using the existing second conveying roller pair 81 and 83 as illustrated in FIGS. 7 to 9, and is illustrated in FIG. 6C. Similarly to the modification of the first embodiment, the belt conveying means 8 that is independent from the second conveying roller pair 81 and 83 may be provided.

(Third example)
A third example to which the invention of the prior application is applied will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component and member same as a 2nd example, and description is abbreviate | omitted or simplified. Although not particularly described, the configuration not described in the third example, that is, the paper transport device and other configurations and operations thereof are the same as those of the paper transport device 5 of the second example shown in FIGS.

As shown in FIG. 10, when the trailing end Se of the curved sheet S during the conveyance is removed from the support by the guide member 71 or the like, the arrow b shown in FIG. A splash phenomenon occurs in which the trailing edge Se of the sheet S moves in the direction. In particular, in the case of a stiff, high-rigidity sheet S such as thick paper, the reaction force becomes large, and this sudden sound is a problem.
That is, in the transport process, the paper S is forcibly supported by at least two support points, and the rear end Se side of the paper S is the holding portion or guide of the first transport means 6 as one support point. When it is removed from the member 71 or the like, it is supported only at the leading end side, and the trailing end Se of the sheet S instantaneously collides with the conveying surface 82a of the conveying belt 82 by the elastic restoring force of the curved sheet S. The impact at that time increases as the rigidity of the paper S increases. For this reason, the sudden sound generated when the trailing edge Se of the paper S collides with the conveyor belt 82 due to the above-described splash phenomenon not only causes discomfort to the user, but also may cause misunderstanding that a failure has occurred. In other words, whether or not the device is malfunctioning because the above sudden sound occurs even if the paper is transported normally regardless of whether it is a normal paper S or a highly rigid paper S. There is a risk of giving such extra suspicion.

  Therefore, as shown in the figure, in the sheet conveying apparatus 5 of the third example, the belt conveying means 8 includes a pair of roller type pulleys 83 and 84 and a grip roller 81 on which the conveying belt 82 is stretched. A contact member such as a tension roller 85 as a member that contacts the other conveyance belt 82 is not arranged on the conveyance surface 82 a side of the conveyance belt 82. Accordingly, a portion of the conveyance belt 82 on the conveyance surface 82a side has appropriate elasticity, and the impact caused by the trailing edge Se of the sheet S is absorbed by the elastic action of the conveyance belt 82, so Even when the highly rigid paper S is transported, the paper transport device 5 that can ensure quietness is realized and provided.

  The tension roller 85 is formed in two linear portions formed on the conveyor belt 82 so as to be stretched around the pulley pairs 83 and 84, but not on the one conveying surface 82a side, and on the other opposite surface side portion. The roller 85 is pivotally supported at a position in contact with the peripheral surface so as to be displaceable outward from the position across the conveyor belt 82, and the roller 85 is pressed to the right in the drawing by a biasing member (not shown) and biased. Has been. As a result, the tension roller 85 is driven to rotate as the conveyor belt 82 travels, and is always in contact with the inner peripheral surface of the conveyor belt 82 so as to be displaced outwardly by receiving a predetermined urging force. A constant tension can be maintained without loosening 82 in the circumferential direction.

  Therefore, according to the paper transport device 5 of this example, the leading end side of the paper S in the paper transport direction is sandwiched and transported by the second transport means 7, and the rear end Se of the paper S is removed from the support by the guide member 71. Even when it collides with the conveyance surface 82a of the conveyance belt 82, it can be sufficiently elastically deformed so that the conveyance surface 82a of the conveyance belt 82 is displaced in the collision direction as shown by a two-dot chain line in the figure. Since the impact of the trailing edge Se can be absorbed, the magnitude of the sound generated by the collision can be reduced, and the generation of abnormal noise as the operation sound of the paper transport device can be suppressed and mitigated.

As described above, according to the paper transport device 5 of the third example, the rear end Se of the transported paper S contacts the belt 82 at a location different from the location where it contacts the transport surface 82a of the transport belt 82. Since the tension roller 85 is disposed as a contact member for supporting the sheet S, when the sheet S is conveyed in a predetermined curve, the rear end Se of the sheet S is When the carrier belt 82a collides with the conveyance surface 82a after being separated from either the nip portion or the guide member 71, the collision belt 82 is sufficiently elastically bent to absorb the impact. It is possible to suppress sudden sound (honeycomb) generated by the collision. That is, when the trailing edge Se of the sheet S is in contact with the conveying surface 82a of the conveying belt 82, the contact member does not hinder the deformation of the conveying belt 82 where the trailing edge Se of the sheet S contacts, and the trailing edge of the sheet S is prevented. The conveyor belt 82 can be sufficiently bent in the contact direction of the end Se.
In particular, when a highly rigid sheet S such as a thick sheet is conveyed, even if the rear end Se of the sheet S in the sheet conveying direction comes into strong collision with the conveying belt 82, the impact due to the collision is conveyed to the conveying belt. 82 can be absorbed and relaxed by the elastic deformation of 82, and the generated impact sound can be sufficiently suppressed.
Therefore, as described above, sudden noises during paper conveyance can be suppressed, eliminating the user's uncomfortable feeling and avoiding misperception that a failure has occurred, improving the usability of the device. Can be made.

  On the other hand, when the leading edge of the sheet S first contacts the conveying surface 82a side of the conveying belt 82 as in the above-described sheet conveying process, even if no sudden sound is generated by the contact of the leading edge of the sheet S, Since a certain degree of elastic deformation of the conveying belt 82 can be expected, the leading edge of the paper S does not flounce from the conveying surface 82a, that is, does not repel, and is brought into contact with the software, and is shifted to the state in which it is in contact. Is possible. That is, with respect to the conveyance surface 82a of the conveyance belt 82 traveling so as to travel in the sheet conveyance direction, the leading edge of the sheet S conveyed by the first conveyance means 6 for the first time obliquely enters the conveyance angle 82 ( 8), the leading edge of the sheet S can be shifted to the advancing direction by following the conveying surface 82a without repelling the leading edge of the sheet S from the conveying surface 82a. .

  The third example is not limited to the one shown in FIG. 10. For example, if the conveyance belt can be deformed to such an extent that sufficient silence can be obtained, the third example is arranged in a predetermined facing manner as in the configuration shown in FIG. 10. Of the two substantially linear belt running surfaces that are stretched around the pair of pulleys 83 and 84 and formed on the conveying belt 82, the tension / Without being limited to the arrangement of the roller 85, one of the two belt running surfaces including the facing conveying surface side is selected, and the roller is placed at any location on the selected belt running surface. May be arranged. That is, regardless of the rigidity strength in the thickness direction of the paper, the location where the trailing edge of the paper contacts the belt conveyance surface due to the above-described sag phenomenon is almost constant, and the belt deformation is allowed from the contact location. The roller may be arranged so that the tension roller is brought into contact with an appropriate place on the transport surface which is separated by a distance.

In the third example, the above-mentioned predetermined position is secured, and a tension roller is provided for securing tension by pressing and urging outward from the stretched belt. On the contrary, a tension roller for pressing and urging inward from the outside of the belt to ensure tension may be provided.
In the case of this configuration, in addition to the function of imparting tension, a configuration may also be used in which a function of cleaning the outer peripheral surface of the belt is also used. According to the configuration of the tension roller that combines the tension imparting function for the belt and the cleaning function for the belt conveyance surface, the belt conveyance surface can be kept clean, which in turn improves the image quality. We can expect to contribute. That is, the belt conveyance surface can be kept clean, and the surface of the sheet in contact with the belt conveyance surface can be similarly kept clean. In addition, a tension roller and a cleaning roller may be provided separately after securing the above predetermined position, and only a cleaning roller mainly having a cleaning function that does not have a tension applying function as a main function. It may be provided.

As described above, the second conveying means 7 of each paper conveying apparatus 5 shown in FIGS. 1 to 4 and 7 to 10 is configured as a nipping and conveying means for nipping and conveying the paper S. That is, the second conveying means 7 is a second conveying rotation comprising two conveying rotating members arranged opposite to each other, a grip roller 81, a roller-like pulley 83 and a conveying belt 82 stretched between the roller-like pulley 84. Although it has been described as a member pair configuration, the grip roller 81 side is the driving side, and the conveying belt 82 side is described as the driven side that is driven in contact with the grip roller 81, but the drive / driven side is not necessarily defined. However, the technical contents include that the conveyance belt 82 side may be driven.
On the other hand, in the first embodiment of the present invention and the like, the grip roller 81 side is defined as the driving side, and the conveying belt 82 side is defined as the driven side that is driven in contact with the grip roller 81 by the following contents.

  In addition, as described above, the conveyance belt 82 of each of the sheet conveyance devices 5 illustrated in FIGS. 1 to 4 and 7 to 10 has a width of the conveyance belt 82 in the sheet width direction Y of at least the maximum size to be conveyed. As the belt width that is substantially the same as the paper width, that is, the belt width of the conveyance belt 82, a belt width that is at least equal to or larger than the maximum width of the paper to be conveyed is set and secured. Similarly, the pulleys 83 and 84 over which the conveyance belt 82 is stretched and the grip roller 81 that is opposed to the conveyance belt 82 have pulleys and roller lengths in the paper width direction Y (axial longitudinal direction), and the belt width It is continuously formed to have a length equal to or longer than the length of. As a result, the sheet S sent out from the first conveying means 6 always comes into contact with the conveying belt 82 over the entire width of the sheet, and the contact area between the two can be ensured as much as possible. . Along with this, it is possible to transmit the maximum possible force for the conveyance propulsion force that advances the paper S that can be supplied to the paper S from the conveyance belt 82 that is always moved in the conveyance direction in the conveyance direction. Is listed as a feature. In contrast, the first embodiment and the like are configured as follows.

(First embodiment)
With reference to FIG. 11 to FIG. 20, the sheet conveying device 5 </ b> A of the first embodiment will be described. FIGS. 11 and 12 simply show a drive mechanism 22 as a feeding drive means (feeding drive system) of the first conveying means 6 and the second conveying means 7 in the paper conveying apparatus 5A of the first embodiment. ing. FIGS. 13 to 18 show in detail the periphery of the belt conveying means 8A of the second conveying means 7 in the paper conveying apparatus 5A of the first embodiment.
The sheet conveying apparatus 5A of the first embodiment shown in FIGS. 11 to 18 and the like is a second nipping and conveying means as compared with the sheet conveying apparatus 5 shown in FIGS. 1 to 4 and FIGS. The belt conveying means 8A is used in place of the belt conveying means 8 in place of clarifying the driving / following relationship of the conveying means 7, and the conveying belt 82 and the like are in contact with a part of the paper S in the paper width direction Y. The main difference is that they are intermittently configured in the sheet width direction Y, and the material of the conveyor belt 82, the physical property values described later, and the like are specified. The sheet conveying apparatus 5A of the present embodiment is the same as the sheet conveying apparatus 5 shown in FIGS. 1 to 4 and FIGS. 7 to 10 except for the differences described above.

  That is, the second conveying means 7 of the sheet conveying apparatus 5A is a rotating conveying driving means / rotating conveying driving member capable of transmitting a driving force by rotating one of the opposed pairs forming the nip portion as the clamping portion. And the other of the opposed pair is disposed in the outer direction of the paper conveyance path (first conveyance path A) formed between the first conveyance means 6 and the second conveyance means 7, A conveyance belt 82 that conveys (moves and guides) the sheet S toward the nipping portion (nip portion) of the second conveying unit 7 while keeping the state of being in direct contact with the roller 81 and in contact with the leading edge of the sheet S. It is characterized by comprising a belt conveying means 8A (movement guide means) provided with

  Further, the sheet conveying apparatus 5A according to the first embodiment has a maximum sheet width that the width of the conveying belt 82 conveys as compared with the sheet conveying apparatus 5 illustrated in FIGS. 1 to 4 and 7 to 10. Instead of the above-described length, the lengths of the pulleys 83 and 84 and the grip roller 81 are continuously formed in the paper width direction Y so as to be longer than the width of the conveying belt 82. The sheet width direction Y of the conveyance belt 82 in the belt conveyance unit 8A is in contact with a part of the leading edge (including the leading edge, the leading edge surface, and the corner / edge of the leading edge) of the sheet S in the sheet width direction Y. It is characterized by being configured intermittently in the width direction Y.

A plurality of grip rollers 81 are intermittently fixed and arranged on a rotational drive shaft 81a in the paper width direction Y in a skewered dumpling shape. On the other hand, the conveying belt 82 and the pulleys 83 and 84 of the belt conveying means 8A are disposed and arranged corresponding to at least one of the plurality of grip rollers 81 (that is, at least one of the opposed pairs). . Specifically, as shown in FIGS. 11, 16, and 18, three grip rollers 81 are arranged on the rotation drive shaft 81 a, and three grip rollers 81 correspond to and face the three grip rollers 81. The conveyor belt 82 is arranged with a width substantially equal to that of each grip roller 81. This detailed configuration will be described later.
In FIG. 11, in order to clearly show the drive mechanism 22, the arrangement interval of the grip rollers 81 is intentionally shifted in the direction of the rotation drive shaft 81 a, but is shown irregularly. Of course, it is arranged at intervals.

As shown in FIGS. 11 and 12, the drive mechanism 22 includes a paper feed motor 23 composed of a stepping motor as a single drive source and drive means, and a motor gear 24 fixed to the output shaft of the paper feed motor 23. The idler gear 25 meshed with the motor gear 24, the feed roller drive gear 61B meshed with the idler gear 25 and fixed to one end of the shaft 61a of the feed roller 61, the idler gear 26 meshed with the feed roller drive gear 61B, and the idler gear 26, and a feed roller gear 61A fixed to the other end of the shaft 61a near the feed roller 61, a feed roller gear 61A fixed to one end of the rotational drive shaft 81a of the grip roller 81, and the feed roller gear 61A. The above-described idler gear 65 that meshes with the roller gear 61A, and this Meshes with Idoragiya 65, is mainly composed of a pickup roller gear 60A which is fixed to the other end of the shaft 60a of the pickup roller 60 closer.
The paper feed motor 23 is fixed to the housing 80. The idler gears 25, 26, and 65 are rotatably supported by the housing 80, respectively.
As described above, in this example, the paper transport device 5 is compact and space-saving, that is, as illustrated in the first embodiment, the first transport path A is configured with a curvature portion having a relatively small curvature radius. For this reason, the sheet feeding motor 23 is single and serves as the driving means for the first conveying means 6 and the second conveying means 7 and contributes to the compactness of the apparatus.
The reverse roller 62 is driven by a separate system that includes, for example, a solenoid that releases pressure on the feed roller 61 and the like. In FIG. 11, 62b represents what was demonstrated as the torque limiter which is not shown in the example shown in FIGS.

In the example shown in FIGS. 1 to 4, the rotational drive relationship between the pickup roller 60 and the feed roller 61 has been briefly described. In practice, however, as shown in an enlarged view in FIG. The shafts 60a and 61a are connected by the pickup arm member 64, and a solenoid (not shown) and the like are arranged so that the pickup roller 60 swings and displaces through the pickup arm member 64 around the shaft 61a on the feed roller 61 side. It is driven by a combination of springs.
In the actual drive mechanism 22, more drive force transmission members such as gears and timing belts are appropriately disposed between the paper feed motor 23 and the feed roller 61. Here, however, the grip roller 81 is a rotary conveyance drive member. In order to clarify that this is the case, an example is shown in both figures.

  Here, since the conveyance belt 82 of the belt conveyance means 8 is configured to be brought into direct contact with the grip roller 81 (rotational conveyance drive means / rotational conveyance drive member) that is rotationally driven by the drive mechanism 22, the conveyance belt 82. The variation in the linear velocity of the conveyor belt 82 can be reduced by driving the grip roller 81 side than when driving the side. As a result, the conveyor belt 82 that rotates toward the clamping portion of the second conveyor means 7 is disposed outside (in the outer direction) of the turn of the first conveyor path A (paper transport path), so that the first conveyor path A It is possible to improve the transportability of relatively stiff paper such as thick paper at the turn portion, and by driving the grip roller 81 that faces and directly contacts the transport belt 82 and rotates the transport belt 82, a stable line can be obtained. It becomes possible to convey the sheet to the second conveying means 7 and the subsequent ones at a speed.

Next, with reference to FIGS. 13 to 20, a detailed configuration mainly on the side of the belt conveying means 8 </ b> A arranged facing the grip roller 81 will be described.
Compared with the belt conveying means 8 of the paper conveying device 5 shown in FIGS. 1 to 4 and 7 to 10, the belt conveying means 8 </ b> A of the paper conveying device 5 </ b> A has a material and physical property values (elastic member). In this example, three pulleys are used in place of the three pulleys 83 fixed on the pulley shaft 83a in that the rubber hardness (hardness), the elongation ratio) and the thickness are specified as follows. 83 is rotatably supported on the pulley shaft 83b, and instead of the pulley 84 fixed on the pulley shaft 84a, three pulleys 84 are rotatably supported on the pulley shaft 84b, Each pulley 83, 84 is formed of a resin such as polyacetal resin, a belt support member 86 is used as a support member that rotatably supports and supports each pulley 83, 84, and in the axial direction thereof. Long continuous pulley Instead of 84a, wherein the point and described below are used three pulley shaft 84b of the short metal lengths in the axial direction is mainly differs.

  As shown in FIG. 4, the grip roller 81 and the conveyor belt 82 are in contact with each other on a line connecting the center of the rotation drive shaft 81a of the grip roller 81 and the center of the pulley shaft 83b, as shown in FIG. A sandwiching portion (nip portion) is formed at a portion including the contact point. The pulleys 83 and 84 are made of, for example, a resin such as a polyacetal resin having good lubrication performance and wear resistance / durability, and the weight is reduced.

The conveyor belts 82 arranged at the three locations are the same except for the setting of a spring load, which will be described later, and therefore, one of them will be described as a representative. For example, ethylene / propylene rubber (EPDM) as an elastic member is used as the material of the conveyor belt 82, and a base material (usually, the belt is often used to attach rubber to a base material such as a fabric in which fibers are knitted). It is made of rubber without any material.
The material of the conveyance belt 82 is not limited to the above, and for example, a material formed of any one of chloroprene rubber (CR), urethane rubber (U), silicon rubber, or silicone rubber (Q) is used. May be.

The transport belt 82 is rotated by the pulley shaft 83b and the pulley 83 rotatably supported by the pulley shaft 83b due to the assembly of the pulleys 83 and 84 to the belt support member 86 via the pulley shafts 83b and 84b. It is spanned with a predetermined tension between the pulley 84 supported freely.
That is, the pulley shafts 83b and 84b are fixed and supported by the belt support member 86 so as to keep the distance between the shafts constant. At this time, the pulley shafts 83b and 84b are connected to the belt support member 86 so that the circumference of the conveyor belt 82 when the conveyor belt 82 is wound between the pulleys 83 and 84 is larger than the circumference of the conveyor belt 82 alone. It is also a feature point that it is arranged and supported in the case. With the above configuration, when the conveyor belt 82 is assembled on the belt support member 86 as the belt conveyor means 8A, the conveyor belt 82 is elastically adjusted so that the circumference after assembly is larger than the circumference of the conveyor belt 82 alone. It will be used by extending.

  Two bearings 87 are mounted on the pulley shaft 83 b between the three belt support members 86. A spring 91 as an urging means / elastic member pressurizes the pulley shaft 83b via a bearing 87 to generate a transport force for transporting the paper. As described above, the pulley shaft 83b and the pulley shaft 84b are fixed by the belt support member 86 so as to maintain a constant distance between the shafts, and the pulley shaft 84b is configured to be swingable about the pulley shaft 83b. ing.

The belt support member 86 is integrally formed of a resin such as polyacetal resin, and the weight is reduced. A spring pedestal 86 a that locks one end of the spring 92 is integrally formed on the back wall of the belt support member 86. Retaining rings for preventing the pulley shafts 83b and 84b from coming off are mounted in the vicinity of the pulley shafts 83b and 84b protruding from the belt support member 86.
As shown in FIG. 14, the back surface of the belt support member 86 is biased between the spring base 86 a of the belt support member 86 and the spring receiving member 93 fixed to the opening / closing guide 79, thereby conveying the belt 82. A spring (compression spring) 92 is mounted as a biasing means that biases the grip roller 81 in a direction in which it is always pressed against the grip roller 81 shown in FIG.

  As shown by hatching in FIG. 15, a positioning portion 86b for positioning the transport belt 82 at a predetermined position is integrally formed at the lower portion of the belt support member 86, and this positioning portion 86b is transported. By contacting the guide member 72, the position of the conveyance belt 82 itself is positioned. Also, as shown in FIGS. 14 and 17, the positioning belt 86 and the transport guide member 72 come into contact with each other by the biasing force of the spring 92 as the biasing means / elastic member, so that the transport belt 82 is brought into a predetermined position. It is positioned so that a belt protruding amount h from a conveyance guide rib 72b formed to protrude inward from the conveyance guide member 72 can be secured.

As shown in detail in FIG. 17, the bearing 87 is formed with a U-shaped groove 87a, and the pulley shaft 83b is loosely fitted to the U-shaped groove 87a, so that the pulley shaft 83b is urged by the urging force of the spring 91. The conveying belt 82 is urged and pressurized in a direction in which the conveying belt 82 is pressed against the grip roller 81. The position of the pulley shaft 83b is fixed when the conveying belt 82 is brought into pressure contact with the grip roller 81, but the pulley shaft 84b is configured to be swingable in the direction of the arrow shown in FIG. 15 about the pulley shaft 83b. .
Referring to FIGS. 14 and 17, it has been described above that one end of the spring 92 presses the belt support member 86, but the other end is supported and locked by the spring pressurizing table 94. The spring pressing base 94 is configured to be movable and fixed at an arbitrary position with respect to a slit 93a formed in the spring receiving member 93 along the direction of the urging force of the spring 92. In the figure, an example of fastening and fixing with screws is shown. With this configuration, the spring load as an urging force of the spring 92, that is, the applied pressure can be changed by arbitrarily changing the compression length of the spring 92 at three locations. In the example of the present embodiment, the same spring specifications such as the spring load, spring length, and shape of the two springs 91 are used. Similarly, the same spring specifications such as spring load, spring length, and shape of the three springs 92 are used.

  Although the description will be omitted, as shown in FIGS. 18A and 18B, the configuration of the main body side of the paper feeding device 3 is divided into the first conveyance path A, as in a general conventional paper feeding device. Then, with respect to the apparatus main body 78 provided with the housing 80 and the like shown in FIGS. 3, 4 and 7 to 10, the hinge fulcrum shaft 76 provided at the lower part of the apparatus main body 78 is used as a swing fulcrum. The opening / closing guide 79 as an opening / closing unit employs a configuration that can be opened and closed in the directions of arrows C and D in FIG. With such an open / close configuration, the jammed paper (jam paper) is removed.

As described above, the conveying belt 82 of the belt conveying means 8A in the present embodiment has a pair of roller-like pulleys depending on the relationship of assembling the pulleys 83 and 84 to the belt support member 86 via the pulley shafts 83b and 84b. It is spanned between 83 and 84 with a predetermined tension. The conveyor belt 82 is pressed against a grip roller 81 driven by a pulley 83 provided so as to be freely rotatable by an urging force of a spring 92, and is driven to rotate as the grip roller 81 rotates.
In such a basic configuration around the belt conveying means 8A in the present embodiment, there are appropriate conditions for the conveying belt 82, and items to be considered when determining the appropriate conditions are as follows. It is done. That is,
(1) Rotational load when the conveyor belt 82 is driven to rotate by increasing the extension ratio (2) Looseness of the conveyor belt 82 when the conveyor belt 82 is used by decreasing the extension ratio.

Regarding the relationship between the rubber hardness of the conveyor belt 82 and the stretch rate, the following phenomenon is generally expected. That is, if a low hardness belt belt is used as the conveyance belt 82, the conveyance belt 82 is loosened, and the conveyance belt 82 may not function as the above-described movement guide means. For example, when the stretch rate of the conveyor belt 82 is low, regardless of the rubber hardness, if the conveyor belt 82 is stretched along the pulleys 83 and 84, as shown by broken lines in FIG. The conveyor belt 82 in the straight portion between the pulleys 83 and 84 swells outward.
Further, when a high hardness belt belt is used as the conveyor belt 82, the tension of the conveyor belt 82 increases and the rotational load (load load) applied to the pulleys 83 and 84 via the conveyor belt 82 increases. As a result, the torque for rotating the conveyance belt 82 becomes larger than necessary, and it becomes difficult to follow the grip roller 81 and follow it. That is, the conveyance belt 82 slips with respect to the grip roller 81, and the grip roller 81 Since the linear velocity of the conveyor belt 82 is slower than the linear velocity (hereinafter also referred to as “linear velocity”), the intended linear velocity of the conveyor belt 82 does not appear, and the effects of the present invention cannot be exhibited.

Therefore, in order to obtain the necessary functions of the conveyor belt 82 while avoiding the looseness of the conveyor belt 82 and the rotational load more than necessary, the expansion rate of the conveyor belt 82 and the rubber under the condition that the thickness of the conveyor belt 82 is constant. A necessary threshold was set for the hardness of. That is, as a necessary threshold value / evaluation standard, it means that the linear velocity of the conveyance belt 82 is substantially the same as the linear velocity of the grip roller 81, in other words, the intended linear velocity of the conveyance belt 82 can be obtained. To do.
Based on the above threshold value, a test evaluation was performed as to whether or not the combination of each parameter of the stretching ratio and the hardness of the conveyance belt 82 is suitable for holding and stable conveyance of a sheet (sheet). The evaluation results are shown in Table 2 below.

As basic test conditions of Example 2, tests were performed under the same test conditions as those of Example 1 shown in FIG. 5 and Table 1 except for the following special conditions. Regarding the relationship between the linear hardness of the grip roller 81 and the linear velocity of the grip roller 81, the test results shown in Table 2 below were obtained as the relationship between the rubber hardness of the conveying belt 82 made of ethylene / propylene rubber and the expansion ratio. As shown in Table 2, the stretch rate (%) of the conveyor belt 82 is changed in seven stages of 10 to 4%, and the hardness of the rubber of the conveyor belt 82 (JIS K 6253 A type) is 40 °, 60 °, 80 It was carried out by changing it in three stages.
As a special test condition for Example 2, the thickness of the conveyor belt 82 was fixed to 1.5 mm. The other test conditions of Example 2 are that the distance between the shafts of the pulley shafts 83b and 84b is constant 13 mm, and the linear velocity of the grip roller 81 is constant. The test conditions are the same as those of the first embodiment, including that the paper can be conveyed.

Here, the expansion rate of the conveyor belt 82 in this embodiment is the circumference of the conveyor belt 82 alone when the conveyor belt 82 is wound between pulleys 83 and 84 (each belt holding and rotating member) having a constant inter-axis distance. This is expressed as a percentage (%) ratio of the extension of the conveyor belt 82 from the length. For example, when the circumference of the conveyance belt 82 before winding between the pulleys 83 and 84 with a constant inter-axis distance is 100 mm, after winding between the pulleys 83 and 84 with the same inter-axis distance. The expansion ratio when the peripheral length of the conveyor belt 82 is expanded to 110 mm is represented by 110/100 × 100 (%) − 100 (%) = 10 (%). The same applies to the first embodiment described above.
The concept of the belt stretch rate is a well-known belt tensioner that has a fixed center-to-axis distance between pulleys as a belt holding and rotating member. It does not apply to those that apply tension to the belt by a dedicated means. On the other hand, the belt conveying means as the movement guide means of the present invention has a simple configuration with a small number of parts, such as simply winding and extending the conveying belt 82 between pulleys 83 and 84 having a constant inter-axis distance, and is inexpensive. Therefore, it is a novel one that is not present in conventional sheet conveying apparatuses and image forming apparatuses.

In Table 2, the details of symbols ◯, Δ, and X indicating the test evaluation results for the conveyance performance of six types of paper similar to those shown in Table 1 are as follows.
◯: Indicates that the linear velocity of the conveyor belt 82 is substantially the same as the linear velocity of the grip roller 81 (a linear velocity as intended by the conveyor belt 82 has been obtained) and can be used without any problem in practice. A combination range of levels.
Δ: As a result of appearance observation, as indicated by a broken line in FIG. 19A, when the stretch rate of the conveyor belt 82 is 4%, the conveyor belt 82 in the straight portion between the pulleys 83 and 84 bulges outward. It means that it has stopped (bulged). Therefore, for example, in the sheet feeding device 3 in FIG. 1, the lower sheet feeding tray is further disposed below the lower sheet feeding tray 51, and the conveyance guide member 71 also serves as the second conveyance path B and the guide. In the case of the configuration of this embodiment, the conveyance belt 82 interferes with the conveyance guide member 71 as indicated by a broken line in FIG.
However, when there is no sheet conveyance path from the lower sheet feed tray (see FIGS. 1 to 4), the conveyance guide member 71 indicated by a solid line in FIG. If it is shifted to the left in the figure to the extent that it does not interfere, there is no practical problem, so that it can be used. This is because there is no problem with respect to the movement guide of the leading end of the sheet even if the distance in the sheet conveyance direction between the downstream end 71c of the conveyance guide member 71 and the conveyance belt 82 is long.

  In other words, when the hardness of the conveyor belt 82 is 40 to 80 ° and the extension ratio is 4%, the conveyance surface 82a of the conveyor belt 82 that comes into contact with the sheet is conveyed. When the conveying guide member 71 bulges in a direction that interferes with the downstream end 71c of the guide member 71 and the like, the conveyance guide member 71 is slightly displaced to the left in the position away from the conveying surface 82a so as not to interfere with the conveying surface 82a (FIG. 19B). This means that the conveyor belt 82 that satisfies the special condition can be adopted.

  X: Since the extension rate and hardness of the conveyor belt 82 are large, the load applied to the pulleys 83 and 84 is large, and the belt rotation load increases, so that the conveyor belt 82 slips with respect to the grip roller 81 and the grip roller 81 Since the linear velocity of the conveyor belt 82 becomes slower than the linear velocity, the intended linear velocity of the conveyor belt 82 does not come out, indicating that the effect of the belt system of the present invention cannot be exhibited.

From the test evaluation results in Table 2,
Hardness 40 ° ⇒ Elongation rate 5-10%
Hardness 60 ° ⇒ Elongation rate 5-7%
Hardness 80 ° ⇒ Elongation rate 5%
It was found that the hardness and elongation rate of the conveyor belt 82 should be set under the conditions. In addition, it was found that when the rubber hardness is small, the influence on the rotation of the conveying belt 82 is small even if the expansion rate is large.
However, at any hardness of 40 to 80 °, an elongation rate of 4% is an evaluation result Δ, and can be employed with the special conditions described above.

A third embodiment will be described with reference to FIGS. In this third embodiment, the thickness of the conveyor belt 82 is regarded as a parameter instead of the condition in which the thickness of the conveyor belt 82 is made constant as compared with the above-described second embodiment. The main difference is that a necessary threshold value is set for the hardness, and the rubber hardness test range is 40 ° to 80 ° with high accuracy in increments of 10 °.
Other than the above differences, the second embodiment is the same as the second embodiment. That is, with respect to the thickness, elongation ratio, and rubber hardness of the conveyor belt 82 in this embodiment, as a necessary threshold value / evaluation standard, the linear velocity of the conveyor belt 82 is substantially the same as the linear velocity of the grip roller 81 ( This means that a linear velocity as intended by the conveyor belt 82 can be obtained). Based on the above threshold value, a test evaluation is performed as to whether or not the combination of the parameters of the thickness of the conveyor belt 82, the stretch ratio, and the hardness of the rubber is suitable for holding and stably conveying the sheet (sheet). went. The evaluation results are shown in FIGS. 22, 24, and 26, it is noted that the same test / evaluation results as in Example 2 are included in part. That is, when the thickness of the conveyance belt 82 is 1.5 mm, the hardness of the rubber of the conveyance belt 82 is 40 °, 60 °, 80 °, and the expansion ratio of the conveyance belt 82 is 10 to 4% in combination. The evaluation results are the same as in Example 2.

The basic test conditions of Example 3 were tested under the same test conditions as in Example 2 except for the conditions specified below, and the linear velocity of the conveyor belt 82 was substantially the same as the linear velocity of the grip roller 81. The test results of FIGS. 22 to 26 were obtained as the relationship between the thickness of the conveying belt 82 made of ethylene / propylene rubber, the hardness of the rubber, and the elongation ratio. As shown in FIGS. 22 to 26, the rubber thickness of the conveyor belt 82 is increased from 1.5 mm to 4.0 mm in increments of 0.1 mm (when the rubber hardness is 40 °), and also to 3.5 mm (rubber hardness). In the case of 50 °), it is also changed to 3.2 mm (in the case of rubber hardness 60 °, 70 °, 80 °), and the stretch rate (%) of the conveyor belt 82 is changed in 7 steps from 10 to 4%. In addition, the hardness of the rubber of the conveyor belt 82 (JIS K 6253 A type) was finely changed in five stages of 40 °, 50 °, 60 °, 70 °, and 80 °.
The test conditions of Example 3 other than the above are the same as in Example 2 (the distance between the shafts of the pulley shafts 83b and 84b is constant 13 mm, the linear velocity of the grip roller 81 is constant, the room temperature environment, and the paper type) The test conditions of Examples 1 and 2 are the same, including the ability to transport six types of paper having a metric basis weight).

  22 to FIG. 26, the details of symbols ○, Δ, and X indicating the test evaluation results for the conveyance performance of six types of paper similar to those shown in Table 1 and the technical contents in the case of Δ are the same as those in the second embodiment. Therefore, detailed description thereof is omitted. However, in the case of the test evaluation result Δ, as in Example 2, the hardness of the conveyor belt 82 is 40 to 80 °, and the extension ratio is 4%. When the rubber thickness is 1.5 mm or more, when the conveyance surface 82a of the conveyance belt 82 that comes into contact with the sheet swells in a direction that interferes with the downstream end 71c of the conveyance guide member 71, the conveyance guide member 71 is By disposing at a position far from the transport surface 82a (a position slightly shifted to the left in FIG. 19B) so as not to interfere with the transport surface 82a, the transport belt 82 satisfying the special condition can be employed. Means.

As shown in the test evaluation results shown in FIG. 22 to FIG. 26, that is, under the condition that the combination relationship of the three parameters of the thickness of the conveyor belt 82, the hardness of the rubber, and the elongation rate becomes the evaluation result ○. It has been found that the thickness, the hardness of the rubber, and the elongation ratio should be set. Further, it was found that, as in Example 2, when the hardness of the rubber is small, the influence on the rotation of the conveying belt 82 is small even if the expansion ratio is large. However, as described above, the elongation rate of 4% is the evaluation result Δ at any hardness of 40 to 80 °, and can be employed with the special conditions described above.
Although the thickness of the conveyance belt 82 differs depending on the relationship between the hardness of the rubber and the stretch ratio, it can be seen from the test evaluation results shown in FIGS. However, when comprehensively considering the material saving and resource saving of the conveyor belt 82, the costs associated therewith, and manual assembly and mounting workability of the conveyor belt 82 to the pulleys 83 and 84, the upper limit value is naturally set. It goes without saying that it can be constrained.

  Here, with regard to the setting of the rubber hardness of the conveyor belt 82, the rubber hardness setting from a normal or general design has a range of ± 5 ° as a design tolerance or error. From such a point of view, the hardness of the rubber of the conveyor belt 82 from which the test evaluation results shown in FIGS. 22 to 26 are obtained is 85 °. It can be said that setting the hardness of the rubber described as 40 ° in the drawing as the lower limit value to 35 ° is a concretely valid setting.

  With reference to FIG. 20 and FIG. 27, the reason for setting the lower limit of the thickness h2 of the conveying belt 82 to 1.5 mm or more will be supplemented. At both ends of the pulley 83, a flange shape 101 protruding in the centrifugal direction from the pulley 83 is integrally formed so that the conveying belt 82 does not come off the pulley 83. The height h1 of the flange shape 101 is normally set to 1.0 mm. On the other hand, the thickness h2 of the conveyor belt 82 is set so that the outer peripheral surface of the flange shape 101 does not protrude from the outer peripheral surface of the conveyor belt 82 even when the conveyor belt 82 is worn in consideration of the secular change, that is, h1> h2. It is necessary to set as follows. Therefore, a paper passing durability test was performed to confirm how much the thickness h2 of the conveying belt 82 changes depending on the number of paper passing. The result is shown in FIG.

In FIG. 27, the horizontal axis represents the number of sheets passed (× 1000), and the vertical axis represents the amount of change in thickness (amount of wear) (mm) of the conveyor belt 82. As shown in the figure, the maximum value of the thickness change amount (mm) of the conveyance belt 82 was obtained by the paper passing durability test of the conveyance belt 82. In this paper passing durability test, the conveyor belt 82 is subjected to an abrasion-resistant resin treatment, and the material thereof is ethylene / propylene rubber (EPDM: shown as EP rubber in FIG. 27), and it is most worn in hardness. The one having a hardness of 40 ° (hereinafter referred to as “YA product”), which is considered to be easy to do, was used. Then, this YA product was incorporated in the same manner as in Examples 2 and 3, and a paper passing durability test result was conducted. As a result, as shown in the figure, when 3.7 million sheets of plain paper (PPC paper) are passed, the maximum value of the thickness change amount of the conveying belt 82 is about −0.42 mm (the target value is, for example, 3.7 million). It was set to −0.5 mm or less at the time of sheet passing).
Therefore, the height h1 of the flange shape 101 is usually about 1.0 mm, and the maximum value of the change amount of the thickness h2 of the conveyance belt 82, which is found from the durability test result, is about -0.42 mm. Considering a certain point, the thickness h2 of the conveyor belt 82 is such that the outer peripheral surface of the conveyor belt 82 protrudes from the outer peripheral surface of the flange shape 101 by a thickness of 0.5 mm (h2-h1 = 0.5). It was determined. That is, the practical lower limit value of the thickness h2 of the conveyor belt 82 is set to 1.5 mm.
In addition, when the height h1 of the flange shape 101 is set to 0.5 mm, for example, the conveyance belt 82 is easily set on the flange shape 101 and is thus set to 1.0 mm. The setting of the height h1 of the flange shape 101 is not limited to the setting of 1.0 mm as long as it does not have to take into account the material saving associated with the thickness setting of the flange shape 101 itself and the conveyor belt 82. Needless to say.
In general, it is known from the results of the paper passing durability test that the wear amount of the conveyor belt 82 tends to decrease as the hardness of the rubber increases. In addition, regarding the maximum value of the thickness change amount of the conveyance belt 82 when a paper having a relatively high rigidity, for example, a paper having a metric basis weight of 256 g / m ² (see Table 1) or more is passed, The transport belt having a hardness of 40 ° used in the test may be slightly larger than the case of plain paper (in the case of the same linear velocity as that of plain paper). However, in the case of the above-mentioned relatively stiff paper, in order to secure the heat capacity at the time of fixing, the linear speed is made much slower than the linear speed of plain paper (about 3 minutes of the linear speed of plain paper). 1), the number of passing sheets within the mechanical life is considered to be practically equivalent to the maximum value of the change in thickness of the conveying belt when plain paper is passed. Alternatively, it may be possible to cope with this problem by setting the conveyance belt 82 to a high hardness in addition to a relatively rigid sheet.

  In the example shown in FIG. 20, the roller width of the grip roller 81 is set wider than that of the pulley 83. The height h1 of the flange shape 101 provided integrally with the pulley 83 is set to be smaller than the thickness / height h2 of the conveyor belt 82. For this reason, a gap d1, which is a gap dimension, is maintained between the grip roller 81 and the flange shape 101, so that the conveyance belt 82 is not detached due to the relationship of h2> h1> d1, and the paper Since interference with the flange shape 101 does not occur, good paper conveyance performance can be ensured without damaging the paper.

Next, the properties of the front and back surfaces of the conveyor belt 82 and the surface treatment state will be described. The outer peripheral surface of the pulleys 83 and 84 of the present embodiment that contacts the back surface of the conveyor belt 82 is smooth and is in a smooth state. On the other hand, in the case of a belt used on the drive side in the past, for stability to keep the linear speed and speed constant, it is toothed (tooth shape of gear) so that the belt and the pulley are securely engaged with each other. Yes. The conveyor belt 82 of this embodiment is driven and rotated by frictional contact with the grip roller 81 shown in FIG. 20, for example, and as a result, the pulleys 83 and 84 around which the conveyor belt 82 is stretched are also driven and rotated. Therefore, slipping between the conveyor belt 82 and the pulleys 83 and 84 has no practical problem, and it is important whether the grip roller 81 and the conveyor belt 82 are rotated.
The outer circumferential surface of the conveyor belt 82 is generally subjected to a texture (drawing) process with a concavo-convex pattern of a mold. Incidentally, the belt polishing for applying the polishing to improve the accuracy of the thickness of the belt is performed to cope with paper dust adhering to the paper. If the outer peripheral surface of the conveyor belt 82 is smooth and smooth, the conveyor belt 82 cannot slip with respect to the driving rotation of the grip roller 81 and may slip. There is a difference that the surface treatment method is different between the texturing and the belt polishing, and the texturing is cheaper than the belt polishing.

  Further, an additional test was performed using the friction coefficient of the outer peripheral surface of the pulley 83 with respect to the back surface of the conveying belt 82 in contact with the outer peripheral surface of the pulley 83, the rubber hardness of the conveying belt 82, and the friction coefficient of the outer peripheral surface of the pulley 83 as parameters. As a result, the following results were obtained. That is, the corresponding results of hardness 40 ° → friction coefficient 2.6, hardness 60 ° → friction coefficient 1.8, hardness 80 ° → friction coefficient 1.2 were obtained. Conventionally, it has been confirmed that the friction coefficient of the outer peripheral surface of the pulley 83 is within a practical range up to 0.8. In addition, even belts of the same hardness have different materials depending on the components to be blended, so that a certain amount of width is allowed for the friction coefficient of the pulley outer peripheral surface. Considering this point, it is considered that the allowable lower limit value of the value of the friction coefficient 1.2 when the belt hardness is 80 ° is about 0.8. Therefore, the friction coefficient of the outer peripheral surface of the pulley 83 with respect to the back surface of the conveyor belt 82 is considered to be at a level that causes no practical problem if it is in the range of 0.8 to 2.6.

Therefore, according to the first embodiment, the following advantages and effects are achieved. First, as a combination range of the thickness of the conveyor belt 82, the hardness of the rubber (JIS K6253 A scale), and the expansion ratio, the thickness is 1.5 mm or more, and the rubber hardness is 40 to 80 degrees (with a tolerance of In consideration of the condition that it is 35 to 85 degrees) and the expansion rate is 10 to 5%, the sheet including the leading edge of the sheet (sheet) can be removed by appropriate elastic displacement and deformation of the conveying belt 82. The sheet can be stably conveyed while being held.
Secondly, the conveyance belt 82 of the belt conveyance means 8A is configured to directly rotate with the grip roller 81 (rotational conveyance drive means / rotational conveyance drive member) that is rotationally driven by the drive mechanism 22, so that the conveyance belt The variation in the linear velocity of the conveyor belt 82 can be reduced by driving the grip roller 81 side than when driving the 82 side. As a result, the conveyor belt 82 that rotates toward the clamping portion of the second conveyor means 7 is disposed outside (in the outer direction) of the turn of the first conveyor path A (paper transport path), so that the first conveyor path A It is possible to improve the transportability of relatively stiff paper such as thick paper at the turn portion, and by driving the grip roller 81 that faces and directly contacts the transport belt 82 and rotates the transport belt 82, a stable line can be obtained. It becomes possible to convey the sheet to the second conveying means 7 and the subsequent speeds.

This advantage and effect can be easily understood by considering the following technical contents. That is, when the grip roller 81 is driven, the linear velocity of the grip roller 81 is determined only by the outer diameter and the rotational speed of the grip roller 81 itself. On the other hand, considering the case of driving the conveyor belt 82 side, when the conveyor belt 82 is driven, the conveyor belt 82 is driven by a roller-like pulley 83 (belt drive roller, main pulley) provided inside the conveyor belt 82. Is generally driven.
In this case, the linear velocity of the conveyor belt 82 is not limited to the outer diameter and the rotational speed of the pulley 83 provided inside the conveyor belt 82, but varies in the thickness of the conveyor belt 82 due to component variations and the thickness due to wear of the conveyor belt 82. Or the slip between the conveyor belt 82 and the pulley 83. Therefore, driving the grip roller 81 side rather than driving the conveyance belt 82 side can reduce variations in the linear velocity of the conveyance belt 82.

Third, the pulleys 83 and 84 (first and second belt holding and rotating members) are pivotally supported by the belt supporting member 86 (supporting member) so as to keep the distance between the shafts constant. The pulley shafts 83b and 84b of the pulleys 83 and 84 are arranged such that the circumference of the conveyor belt 82 when the conveyor belt 82 made of an elastic member is wound between the pulleys 83 and 84 is larger than the circumference of the conveyor belt 82 alone. In this embodiment, the belt support member 86 is provided with a mechanism for tensioning the belt, which is generally used as a tensioner or a tie toner, as a means for tensioning the belt. Since the configuration is such that tension is applied by elastically extending between the pulleys 83 and 84, compared with a conventional configuration in which a mechanism such as a tensioner is provided. Le, space saving, cost reduction can be realized.
As a result, in the sheet conveying apparatus that can improve the sheet conveying property having relatively high rigidity such as thick paper in the turn portion of the first conveying path A, the mechanism is simple, and space saving and cost reduction can be realized. In addition, the effect described in the column of the effect of the invention described above is also exhibited.
Fourth, since the friction coefficient of the outer peripheral surface of the pulley 83 with respect to the back surface of the conveyor belt 82 is set in the range of 0.8 to 2.6, the conveyor belt 82 can be rotated stably and stably. The paper can be gripped.

  As described above, the belt conveying means 8 of each of the paper conveying devices 5 and 5A is such that one of the opposed pairs of the second conveying means 7 (the nipping and conveying means) is the leading edge or leading edge (tip, leading edge surface) of the paper (sheet). The nip portion with the grip roller 81 while gradually increasing the contact area depending on the degree of rigidity of the paper while maintaining the contact / contact state with the front end corner portion / edge). It can be said that this is an example of movement guide means for moving and guiding the paper S toward the clamping unit. Therefore, the movement guide means is not limited to the belt conveying means 8 and 8A, and may be anything as long as it has the above-described configuration and function and exhibits the above-described effects.

In the above embodiments, examples, and modifications, as shown in FIG. 1, the present invention is conveyed from the sheet storage means (paper feed tray 51) in the image forming apparatus that is a copying machine to the image forming means main body. However, the present invention is not limited to this, and the image forming apparatus is not limited to this example, and the front end of the image forming apparatus is directed upward from the upper part of the fixing device 11 in the apparatus main body. A paper conveying device (for example, see FIG. 21B) configured to discharge the paper S to be discharged from the apparatus main body toward the paper discharge tray 9 in a substantially horizontal direction, or provided outside the apparatus main body. The sheet placed by the user on the substantially horizontal manual feed tray 67 is pulled into the apparatus main body while maintaining the horizontal posture, and the posture is changed upward to reach the image forming unit in the apparatus main body in the vertical direction. Transporting paper that is transported to the transport path It may be applied to a device.
That is, in the above-described embodiment and modification, the example in which the different paper (sheet) conveyance direction is changed from the substantially horizontal direction to the upward direction in the vertical direction (substantially vertical upward direction) has been described. Without being limited, it may be changed from a substantially horizontal direction to a downward downward direction (substantially vertical downward), or a vertical downward or upward change to a substantially horizontal direction (for example, FIG. 21A). Or both may be in an oblique direction or the like.

  In each of the above-described embodiments, examples, and modifications, the first transport unit and the second transport unit are both nipping and transporting units. However, depending on the transport direction of each transport unit alone, the lower surface of the transport target is set. If it is only necessary to support and convey, it is not necessary to use a nipping / conveying means in which a nipping portion by an opposing member is formed.

The members constituting the first conveying unit, the second conveying unit, and the pickup roller are not limited to those described above, and are substantially long cylindrical roller members that have a predetermined length in the axial direction of each rotating shaft. The roller member may be a short cylindrical roller member as appropriate, or a plurality of roller members or roller members may be intermittently disposed at a predetermined interval on one rotating shaft. May be.
In addition, a guide surface formed by several guide members in the outer and inner contour directions in each of the above-described embodiments is positioned at the above-described several intervals where no roller member or roller member is disposed. Good. If these guide surfaces are arranged in an appropriate regular symmetry with respect to the conveyance center line in the conveyance direction, a belt-shaped guide surface may be formed in the sheet (sheet) conveyance direction, or a substantially linear guide A surface may be formed, or these may be mixed as appropriate.

  In each of the above-described embodiments, examples, and modifications, the FRR paper feed method is adopted as the paper feed separation mechanism. However, the present invention is not limited to this, and the paper that has been fed in a predetermined multi-feed due to friction is separated. For example, an appropriate frictional separation method may be employed as long as the separation mechanism allows only one sheet to continue to advance in the conveyance direction. For example, instead of the reverse roller, a separation claw may be used instead of the above-described feed roller. Alternatively, a friction pad system having a configuration in which a friction pad that is a fixing member is in pressure contact may be employed. That is, in this friction pad system, the friction pad as a friction member is pressed against the feed roller with an appropriate separation angle and separation pressure, and the sheet is placed in the nip between the feed roller and the friction pad formed thereby. I try to let it pass. Therefore, according to the paper feed separation mechanism employing the friction pad method, even if two sheets are pulled out in the overlapping state, the lower sheet receives the resistance from the friction pad between the overlapping sheets. Since it is greater than the resistance due to friction, further movement in the paper transport direction is prevented. On the other hand, the upper sheet is set so that the conveyance force received from the feed roller is larger than the resistance caused by the friction between the overlapping sheets and larger than the resistance received from the friction pad. Only continues in the transport direction.

The present invention relates to an image forming apparatus related to a printer including not only the monochrome copying machine 1 but also a color copying machine, a monochrome laser printer, an inkjet printer, a printer using an ink transfer ribbon, and the like. The transfer device can be applied and applied.
In a color copying machine, after transferring to a tandem color image forming apparatus of a direct transfer system that sequentially transfers and superimposes a sheet (sheet) while being transferred by a transfer body, or after being transferred to an endless intermediate transfer belt as an intermediate transfer body, The present invention can be similarly applied to a tandem type image forming apparatus that performs batch transfer onto a sheet. Needless to say, the endless belt-like photoreceptor can be similarly applied to a single image forming apparatus.

The present invention is not limited to an in-body discharge type image forming apparatus that discharges paper between an image forming unit and a scanner, for example, and an image in which paper is discharged to a paper discharge tray provided on a side portion of the image forming apparatus main body. The present invention may also be applied to a forming apparatus. In addition, a paper path fed from the paper feeding device 3 is formed in a substantially vertical direction (substantially vertically upward) toward the upper portion of the image forming apparatus main body 2. The present invention is also applicable to an image forming apparatus in which the conveyance path until the sheet is discharged to the sheet discharge tray is not in a substantially vertical direction (substantially vertical direction).
The present invention relates to a sheet conveying apparatus for conveying a sheet (paper) from a sheet storage means (paper feed tray) or a sheet stacking means (paper feed table) to a printing unit main body in a printing apparatus including a stencil printing machine. May also be applied.

In the copying machine 1 as the image forming apparatus described above, a document to be read is set manually, but an ADF (automatic document feeder) for automatically reading a plurality of documents (sheets) is provided. The sheet conveying apparatus of the present invention may be applied to the ADF in an equipped copying machine or printing apparatus.
Furthermore, the image forming apparatus is not limited to a copying machine, but is a facsimile, a printer, an ink jet recording apparatus, a printing apparatus, an image reading apparatus mainly having an image reading function having a scanner for reading an image from a document, or the like. You may apply to the compound machine etc. which combined at least two of them. In any case, it is optimal for equipment and devices that need to change the sheet conveyance direction while saving space on the sheet conveyance path, targeting a variety of sheet types as paper types. It can be set as a simple sheet conveying apparatus.

The present invention is not limited to a sheet conveying device arranged in a plurality of paper feeding stages. For example, in the paper feeding device 3 shown in FIG. 1, the upper paper feeding tray 51 and the paper conveying device 5 ′ are removed, The present invention can also be applied to a sheet conveying apparatus including only a single sheet feeding tray 51 and a sheet conveying apparatus 5.
That is, the present invention may be an image reading apparatus including the sheet conveying device according to any one of claims 1 to 11 described in the section for solving the above-described problems. In addition, the image forming apparatus may include the sheet conveying device according to any one of claims 1 to 11 and / or the image reading device. In the present invention, the image forming apparatus may be any one of a copying machine, a facsimile machine, a printer, a printing machine, and an ink jet recording apparatus, or a combined machine in which at least two of them are combined.

  As described above, the present invention has been described with respect to specific embodiments, modifications, and the like. However, the technical scope disclosed by the present invention is that exemplified in each of the above-described embodiments, modifications, or examples. It is not limited, and may be configured by appropriately combining them (for example, configured by appropriately combining the above-described embodiments, modified examples, or examples of the present invention, or the above-described embodiments of the present invention). Can be applied to the first to third examples according to the invention of the prior application, etc.) Within the scope of the present invention, various embodiments, modifications, and examples are configured according to the necessity and application. It will be apparent to those skilled in the art.

1 is a schematic front view showing an overall configuration of an image forming apparatus having a paper transport device to which the present invention is applied. FIG. 2 is an enlarged cross-sectional view of a main part showing an operation state in which the leading edge of the paper reaches a belt conveying unit, showing the paper conveying device of FIG. FIG. 4 is an enlarged cross-sectional view of a main part showing an operation state immediately before the leading edge of the paper reaches the nip portion of the second transport means in the paper transport device of FIG. 2. FIG. 3 is an enlarged cross-sectional view of a main part of the paper transport device for explaining the first embodiment. 6 is a graph for explaining a test result related to variation in paper-type transport time in Example 1. FIG. 9 is a diagram showing a modification of the paper transport apparatus to which the present invention is applied, in which (a) is an example in which belt transport means is provided in the first transport means, and (b) is first and second transport means. Both of these means are provided with belt conveying means, respectively, and (c) is an example in which the belt conveying means is provided separately from the first and second conveying means. FIG. 3 is a cross-sectional view of a main part showing a paper transport device different from FIG. 2 to which the present invention is applied and a paper feed tray stage around the paper transport device. FIG. 8 is an enlarged cross-sectional view of a main part showing an operation state in which the leading edge of the paper reaches the belt conveying means in the paper conveying apparatus of FIG. 7. FIG. 8 is an enlarged cross-sectional view of a main part showing an operation state immediately before the leading edge of the paper reaches the nip portion of the second transport means in the paper transport device of FIG. 7. It is a schematic expanded sectional view which mainly shows another paper conveyance apparatus to which this invention is applied. FIG. 3 is a simplified perspective view showing a drive mechanism in the paper conveying apparatus of the first embodiment. It is a schematic front view of the principal part of FIG. FIG. 3 is a perspective view of a main part when a belt conveyance unit and a conveyance guide member are viewed from the grip roller side in the paper conveyance device of the first embodiment. FIG. 3 is a cross-sectional view of a main part around first and second transport means in the paper transport device of the first embodiment. FIG. 4 is a perspective view of the belt conveyance unit and its surroundings in the paper conveyance device according to the first embodiment when viewed from the grip roller side. FIG. 3 is a perspective view of the periphery of a belt conveyance unit in the paper conveyance device according to the first exemplary embodiment when viewed from the back side of a conveyance guide member. It is sectional drawing of the principal part around the 2nd conveyance means in the paper conveying apparatus of 1st Embodiment. (A) is a schematic perspective view showing a specific opening / closing configuration on the sheet feeding apparatus main body side in the first embodiment, and (b) is an opening / closing guide when removing jammed paper (jam paper). It is a simplified sectional view of the important section showing the opened state. (A) is a simplified front view showing a state in which the conveyance surface of the conveyance belt bulges outward when the extension ratio of the conveyance belt in the first embodiment is a special condition, and (b) is a diagram of the conveyance belt. FIG. 6 is a simplified front view illustrating a state in which the conveyance surface bulges outward and interferes with a conveyance guide member disposed in the vicinity of the conveyance belt. FIG. 3 is a partial cross-sectional view around a conveyor belt and pulleys for explaining the basis for adopting 1.5 mm as the thickness of the conveyor belt in the first embodiment. (A), (b) is a simplified front view for explaining an arrangement example of the first and second conveying means of the sheet conveying apparatus according to the difference in the sheet conveying path. It is a graph which shows the test evaluation result of Example 3, Comprising: It is a graph showing the relationship between the thickness of a conveyance belt in case the hardness of rubber | gum is 40 degrees, and an expansion rate. It is a graph which shows the test evaluation result of Example 3, Comprising: It is a graph showing the relationship between the thickness of a conveyance belt in case the hardness of rubber | gum is 50 degrees, and an expansion rate. It is a graph which shows the test evaluation result of Example 3, Comprising: It is a graph showing the relationship between the thickness of a conveyance belt in case the hardness of rubber | gum is 60 degrees, and an expansion rate. It is a graph which shows the test evaluation result of Example 3, Comprising: It is a graph showing the relationship between the thickness of a conveyance belt in case the hardness of rubber | gum is 70 degrees, and an expansion rate. 6 is a chart showing the test evaluation results of Example 3, and is a chart showing the relationship between the thickness of the conveyor belt and the stretch rate when the rubber hardness is 80 °. 6 is a graph showing the amount of change in thickness of a conveyor belt in a paper passing durability test in Example 3.

Explanation of symbols

1 Copying machine (image forming device)
2 Image forming apparatus body 3 Paper feeding device 4 Document reading device 5, 5 A Paper conveying device (sheet conveying device)
6 First conveying means (first conveying means)
7 Second transport means (second transport means)
8,8A Belt conveying means (movement guide means)
9 discharge tray 10 photoconductor unit 10A photoconductor 11 fixing device 12 developing device 13 transfer device 21 registration roller pair 22 drive mechanism 23 paper feed motor 50 bottom plate (sheet stacking means)
51 Paper feed tray (sheet storage means)
60 Pickup roller 61 Feed roller (one of the opposing pair of first conveying means)
62 Reverse roller (the other of the opposing pair of the first conveying means)
67 Manual feed tray 70 Conveyance guide member (inner side, guide member)
71 Conveying guide member (outer side, guide member)
72 Transport guide member (outer side of longitudinal transport path, guide member)
72a Guide surface 72b Conveyance guide rib 73 Conveyance guide member (for forming an inlet from the paper feed tray to the conveyance path)
79 Opening / Closing Guide (Sheet Conveyor Body)
80 Housing (sheet transport device main unit)
81 Grip roller (one of the opposite pair of the second conveying means, the rotation conveying driving means, the rotation conveying driving member)
81a Rotation drive shaft 82 of grip roller Conveyor belt (belt as the other of the opposing pair of the second conveyer)
82a Conveying surface 83 of the conveying belt Pulley (constituting member of belt conveying means, first belt holding rotating member)
83a, 83b Pulley shaft (downstream shaft of the belt holding and rotating member)
84 Pulley (constituting member of belt conveying means, second belt holding rotating member)
84a, 84b Pulley shaft 86 Belt support member (support member)
91, 92 Spring (biasing means)
A First transport path (transport path)
B Second transport path (transport path)
R1 transport path R2 manual feed path R3 reverse transport path S paper (sheet / sheet-like recording medium, image forming medium)
Y Paper width direction (sheet width direction)
θ Entry angle

Claims (12)

First conveying means for conveying a sheet;
A clamping unit that is disposed downstream of the first conveying unit in the sheet conveying direction and clamps and conveys the sheet conveyed by the first conveying unit in a sheet conveying direction different from the sheet conveying direction of the first conveying unit. Second conveying means to form,
One of the opposing pairs forming the sandwiching portion is a rotation conveyance driving means capable of transmitting a driving force by rotating,
The other of the opposed pair is disposed in the outer direction of the sheet conveyance path formed between the first conveyance unit and the second conveyance unit, and is driven by the rotation conveyance driving unit toward the clamping unit. Belt conveying means comprising a belt for conveying a sheet;
The belt conveying means includes the belt made of an elastic member, at least a pair of belt holding and rotating members that hold the belt so that the belt can run, and a support member that rotatably supports the belt holding and rotating members.
Each belt holding rotation member is supported by the support member so as to hold the distance between the axes constant,
The belt has a hardness of 40 to 80 degrees, and a percentage ratio of an extension from a circumference of the belt alone when the belt is wound between the belt holding and rotating members. A sheet conveying apparatus characterized in that an expansion rate satisfies a condition of 10 to 5%. A guide member that is disposed in the vicinity of the belt in a contour direction of a sheet conveyance path formed between the first conveyance unit and the second conveyance unit, and that guides the sheet to the belt;
When the belt has a hardness of 40 to 80 degrees and the extension ratio is 4%, the belt conveyance surface that comes into contact with the sheet swells in a direction that interferes with the guide member. 2. The sheet according to claim 1, wherein the belt satisfying the special condition can be adopted by disposing the guide member at a position away from the conveyance surface to such an extent that the guide member does not interfere with the conveyance surface. Conveying device. First conveying means for conveying a sheet;
A clamping unit that is disposed downstream of the first conveying unit in the sheet conveying direction and clamps and conveys the sheet conveyed by the first conveying unit in a sheet conveying direction different from the sheet conveying direction of the first conveying unit. A second conveying means to be formed;
A first sheet conveying path formed between the first conveying means and the second conveying means;
A second sheet conveying path that is formed from upstream of the second conveying means to the second conveying means, and is different from the first sheet conveying path;
The first sheet conveyance path and the second sheet conveyance path have a merging conveyance path that merges upstream of the second conveyance means;
One of the opposing pairs forming the sandwiching portion is a rotation conveyance driving means capable of transmitting a driving force by rotating,
The other of the opposed pair is a belt conveying unit that is disposed in the outer direction of the merging conveyance path and includes a belt that is driven by the rotary conveyance driving unit and conveys the sheet toward the clamping unit,
The belt conveying means includes the belt made of an elastic member, at least a pair of belt holding and rotating members that hold the belt so that the belt can run, and a support member that rotatably supports the belt holding and rotating members.
Each belt holding rotation member is supported by the support member so as to hold the distance between the axes constant,
The belt has a hardness of 40 to 80 degrees, and a percentage ratio of an extension from a circumference of the belt alone when the belt is wound between the belt holding and rotating members. A sheet conveying apparatus characterized in that an expansion rate satisfies a condition of 10 to 5%. First conveying means for conveying a sheet;
A clamping unit that is disposed downstream of the first conveying unit in the sheet conveying direction and clamps and conveys the sheet conveyed by the first conveying unit in a sheet conveying direction different from the sheet conveying direction of the first conveying unit. Second conveying means to form,
One of the opposing pairs forming the sandwiching portion is a rotation conveyance driving means capable of transmitting a driving force by rotating,
The other of the opposed pair is disposed in the outer direction of the sheet conveyance path formed between the first conveyance unit and the second conveyance unit, and is driven by the rotation conveyance driving unit toward the clamping unit. Belt conveying means comprising a belt for conveying a sheet;
The belt conveying means includes the belt made of an elastic member, at least a pair of belt holding and rotating members that hold the belt so that the belt can run, and a support member that rotatably supports the belt holding and rotating members.
Each belt holding rotation member is supported by the support member so as to hold the distance between the axes constant,
The belt has a belt hardness of 35 to 85 degrees, and a percentage ratio of an extension from the circumference of the belt alone when the belt is wound between the belt holding and rotating members. A sheet conveying apparatus characterized in that an expansion ratio satisfies a condition of 10 to 5%. A guide member that is disposed in the vicinity of the belt in a contour direction of a sheet conveyance path formed between the first conveyance unit and the second conveyance unit, and that guides the sheet to the belt;
When the belt has a hardness of 35 to 85 degrees and the extension ratio is 4%, the belt conveying surface in contact with the sheet swells in a direction that interferes with the guide member. 5. The sheet according to claim 4, wherein the belt satisfying the special condition can be employed by disposing the guide member at a position away from the conveyance surface to an extent that does not interfere with the conveyance surface. Conveying device. First conveying means for conveying a sheet;
A clamping unit that is disposed downstream of the first conveying unit in the sheet conveying direction and clamps and conveys the sheet conveyed by the first conveying unit in a sheet conveying direction different from the sheet conveying direction of the first conveying unit. A second conveying means to be formed;
A first sheet conveying path formed between the first conveying means and the second conveying means;
A second sheet conveying path that is formed from upstream of the second conveying means to the second conveying means, and is different from the first sheet conveying path;
The first sheet conveyance path and the second sheet conveyance path have a merging conveyance path that merges upstream of the second conveyance means;
One of the opposing pairs forming the sandwiching portion is a rotation conveyance driving means capable of transmitting a driving force by rotating,
The other of the opposed pair is a belt conveying unit that is disposed in the outer direction of the merging conveyance path and includes a belt that is driven by the rotary conveyance driving unit and conveys the sheet toward the clamping unit,
The belt conveying means includes the belt made of an elastic member, at least a pair of belt holding and rotating members that hold the belt so that the belt can run, and a support member that rotatably supports the belt holding and rotating members.
Each belt holding rotation member is supported by the support member so as to hold the distance between the axes constant,
The belt has a belt hardness of 35 to 85 degrees, and a percentage ratio of an extension from the circumference of the belt alone when the belt is wound between the belt holding and rotating members. A sheet conveying apparatus characterized in that an expansion ratio satisfies a condition of 10 to 5%.   The sheet conveying apparatus according to claim 1, wherein the belt has a thickness of 1.5 mm or more.   8. The sheet conveying apparatus according to claim 1, wherein the belt is one of ethylene / propylene rubber, chloroprene rubber, urethane rubber, or silicon rubber. A guide member that is disposed in the vicinity of the belt in a contour direction of a sheet conveyance path formed between the first conveyance unit and the second conveyance unit, and that guides the sheet to the belt;
Each of the belt holding and rotating members includes a first belt holding and rotating member that is disposed to face the rotating and conveying driving unit, and a sheet conveying direction of the second conveying unit that is opposed to the first belt holding and rotating member. A second belt holding and rotating member disposed on the upstream side,
The second belt holding and rotating member is downstream in the sheet conveying direction of the second conveying means from the axial center of the rotating member provided on the outer periphery of the first conveying means, and is second from the downstream end of the guide member. The sheet conveying apparatus according to any one of claims 1 to 8, wherein the sheet conveying apparatus is located upstream of the conveying means in the sheet conveying direction.   The belt conveying means is arranged such that the leading end of the sheet is in contact with the conveying surface of the belt except for the belt portion held by each belt holding and rotating member. The sheet conveying apparatus according to any one of 9.   The sheet conveying apparatus according to claim 1, wherein the sheet is a sheet having relatively high rigidity.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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