JP5251937B2 - Sheet conveying apparatus, image reading apparatus, and image forming apparatus - Google Patents

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 main 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 a model of the image forming apparatus, 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 appropriately selects it. A sheet can be fed from the selected sheet storage unit or a 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 related art example as shown in FIG. That is, as shown in the figure, a sheet feeding tray serving as a sheet storage unit 101 that stores a predetermined number of sheets S of a predetermined paper size and type in each lower stage of the image forming unit main body (not shown). 109 is disposed between the paper feed tray 109 and the image forming means main body, and a sheet S0 is pulled out from the paper feed tray 109, which is the selected stage, in a substantially horizontal direction, and the image forming means on the upper side. A sheet conveying device (sheet conveying device) 102 for feeding toward the main body is provided. The sheet conveying device 102 is fixedly provided with curved guide members 103 and 104 for continuously changing and guiding the traveling direction of the sheet S0 from a substantially horizontal direction to a substantially vertical direction (also a substantially vertical direction) upward. ing. These curved guide members 103 and 104 constitute the above-described curvature portion, and form a sheet conveyance path (sheet conveyance path) A0. B in the figure is a paper transport path for feeding paper S of another paper size or paper type accommodated in a lower paper feed tray or the like.
Note that the sheet conveying apparatus 102 shown in FIG. 16 is an embodiment of the present invention which will be described later, for example, in the prior art example shown in FIGS. 6 and 7 of Japanese Patent Application Laid-Open No. 2004-338923 (see Patent Document 1). In order to compare with the sheet conveying apparatus (sheet conveying apparatus) in FIG.

The curved guide member 103 is formed with a fixed guide surface 103A that is curved in a substantially convex shape to guide the paper S. The curved guide member 104 is provided on the outer side of the curved guide member 104 so as to face the curved guide member 103 on the inner side with respect to the sheet conveyance path A0 of the curvature portion. A fixed guide surface 104A that is curved in a substantially concave shape facing the surface 103A is formed. A flexible sheet-like filler 104a made of elastically deformable mylar or the like is provided at the downstream end of the fixed guide surface 104A in the paper conveyance direction so as to extend to the vicinity of a nip portion of a roller pair 106 described later. .
Reference numeral 105 denotes a roller pair provided on the upstream side of the sheet conveyance path A0. The upstream roller pair 105 (first conveyance unit and nipping conveyance unit) includes a feed roller 105A and a reverse roller 105B. Yes. 106 is a roller pair (second conveying means, nipping and conveying means) provided on the downstream side of the upstream roller pair 105, and 107 is a pickup roller provided on the sheet accommodating means 101 side. These appropriate rollers are driven to rotate in the direction of the arrow so as to convey the paper at each position. An intermediate guide member 108 is provided between the paper feed tray 109 and the outer curved guide member 104 as an outer guide that forms a paper conveyance path between the two 109 and 104.

  However, in the paper conveyance device 102 configured as described above, special paper (hereinafter collectively referred to as “paper S0” such as cardboard and the like, which has relatively high rigidity and strength in the thickness direction of the conveyance object itself such as an envelope). In other words, when trying to convey “highly rigid paper S0”, “highly rigid paper S0” or “strongly stiff paper S0”), the curvature radius of the curvature portion of the paper conveyance path A0 is small. Since the resistance when the high-quality paper S0 is conveyed while being bent according to its curvature is significantly larger than that of paper such as plain paper for copying, the high-stiffness paper S0 cannot be advanced. There is a problem that a stable feeding operation cannot be performed due to a conveyance failure.

  The above operation will be described in more detail as follows. That is, in the sheet conveying apparatus 102 shown in FIG. 16, the sheet S0 is sent out from the upstream roller pair 105 provided in the sheet conveying path A0, and the leading end side of the sheet S0 in the conveying direction reaches the curved guide member 103. The front half of the sheet S0 is curved in the thickness direction by the fixed guide surface 103A of the curved guide member 103. For this reason, when the highly rigid sheet S0 is transported between the curved guide members 103 and 104, the force against the bending that acts on the highly rigid sheet S0 increases, and the resistance force that prevents the transport also increases. It will be. Accordingly, the leading end of the highly rigid sheet S0 does not reach the downstream roller pair 106, and the highly rigid sheet S0 is transported by the upstream roller pair 105 alone, and the highly rigid sheet S0 is curved. In this case, only the transport force by the upstream roller pair 105 is insufficient as a force to advance in the transport direction with respect to the resistance force generated from the curved high-rigidity sheet S0. For this reason, a conveyance failure such as skewing in which the center line of the highly rigid sheet S0 does not coincide with the center line of the conveyance path, or a sheet jam in which the highly rigid sheet S0 is caught by the curved guide member 103 and stops. It becomes easy to do.

On the other hand, in the sheet conveying apparatus configured to convey the sheet by changing the sheet conveying direction to a predetermined value as described above, depending on the shape of the guide member, the trailing edge of the conveyed sheet may have a predetermined value during the conveying process in the sheet conveying apparatus. There is a problem that abnormal noise such as so-called honey noise is generated due to impact contact with the guide member. In particular, when conveying a sheet having a rigidity and strength high in the thickness direction, such as a thick sheet, that is, a sheet having a high rigidity, i.e., a sheet having a high rigidity, that is, a sheet having a sufficiently large conveyance force than the conveyance load, The abnormal noise tends to appear more prominently.
That is, first, as shown in FIG. 17, in the sheet conveyance process from the pickup roller 107 to the feed roller 105A, the sheet adjacent to the downstream end of the sheet stacking surface 101A in the sheet transport direction and the downstream end of the sheet stacking surface 101A. When there is a step between the guide member located on the downstream side in the transport direction, a splash sound is generated when the rear end of the paper passes this step. More specifically, it is located on the downstream side in the sheet transport direction adjacent to the sheet stacking surface 101A defined by the uppermost sheet S0 in the state of being accommodated in the sheet accommodating unit 101, and is formed on the sheet feeding tray 109. If the guide surface 109A occupies a lower position relatively slightly away from the paper transport path with reference to the paper transport path, and there is a predetermined gap between the two 101A and 109A, this is It becomes a level | step difference which produces the said honey sound.

  That is, when the trailing edge of the uppermost sheet S0 remaining in the paper feed tray 109 is transferred from the paper stacking surface 101A to the guide surface 109A of the paper feed tray 109 in the paper transport process, it is indicated by a broken line in FIG. As described above, the rear end of the sheet S0 is shockedly brought into contact with the guide surface 109A. In particular, the sheet S0 having high rigidity has a high ability to maintain its flat shape, and even when deformed, the elastic return ability to the flat shape is high. The tendency for the trailing edge of the sheet S0 to come into contact with impact is promoted, and the above-mentioned splash sound becomes more prominent. That is, the sound generated during the paper transport process during high-stiffness paper transport is louder than other sound generated by the paper transport and is a sudden noise (sudden sound). Prominently appear.

  Also, as shown in FIG. 18, in the paper conveyance process from the pickup roller 107 to the feed roller 105A, if there is a step between the guide surface 109A of the paper feed tray 109 and the outer guide, this step is used as the paper. Also when the rear end S0e of S0 exceeds, a honey sound is generated. That is, the upstream end of the guide surface 108A formed in the intermediate guide member 108 as the outer guide member on the downstream side in the paper transport direction (sheet transport direction) adjacent to the guide surface 109A of the paper feed tray 109 is the paper transport direction. When a predetermined gap is generated between the two papers 109A and 108A and the lower position is relatively slightly separated from the paper conveyance path with respect to the paper conveyance path, When the sheet S0 having a high rigidity is conveyed, it becomes a step that generates a sound, and the honey noise becomes more noticeable as described with reference to FIG.

  Further, as shown in FIG. 19, if there is a step between the guide members constituting the outer guide between the feed roller 105A to the roller pair 106 as the pre-turn roller, this step is formed on the conveyed paper S0. Even when the rear end S0e exceeds, a sneak sound is generated. That is, among the guide members that form the paper transport path A0, the upstream end of the curved guide member 104 in the paper transport direction is more than the downstream end of the guide surface 108A formed on the intermediate guide member 108 in the paper transport direction. If it occupies a lower position relatively slightly away from the paper transport path with reference to the paper transport path and a predetermined gap is generated between the two 108A and 104, refer to FIG. 17 and FIG. In the same manner as described above, this is a step that generates a sneak sound. Similarly, a more pronounced sneak sound is generated when the highly rigid paper S0 is conveyed.

  As a result, among the guide members that form the paper conveyance path, among the guide members arranged on the outer side, the downstream end in the paper conveyance direction on the guide surface formed by one guide member adjacent to each other in the paper conveyance direction If the upstream end in the paper transport direction on the guide surface formed by the other guide member following this is displaced by a predetermined distance in the direction away from the paper transport path, the paper transport progresses. Accordingly, when the rear end of the sheet passes through one guide surface and deviates from the downstream end of the guide surface, the rear end of the sheet rapidly moves in the direction of separation, and collides with the upstream end of the guide member. This creates a shocking squeak noise, and depending on the deformation of the paper in the thickness direction during the paper transport process and the rigidity of the paper itself, the impact at the trailing edge of the paper will increase, resulting in a loud sound. Is big Kunar.

  On the other hand, as shown in FIG. 20, between the feed roller 105A and the roller pair 106, the curved guide member 104, which is an outer guide member, bends the sheet S as indicated by reference numerals Xb to Xd. In the case of a guide shape in which the paper S is turned, that is, a portion of the rear end side of the front end of the paper S is curved, and the direction in which the front end of the paper S advances is rotated in a predetermined direction, the conveyed paper is denoted by the symbol Xa. In other words, when the leading edge of the sheet S hits the curved guide surface A0, the sheet conveying load becomes larger than that with the other signs Xb to Xd. In particular, at the time of paper conveyance with high rigidity, the paper conveyance load increases in any of the paper conveyance states denoted by reference signs Xa to Xd as compared to normal paper, but the leading edge of the high rigidity paper S is curved. Similarly, when it comes into contact with the guide surface A0 (Xa), it becomes the largest in the same manner.

Therefore, in Japanese Patent Application Laid-Open No. 2004-338923 (Patent Document 1), the sheet fed from the first transport unit is transported to the second transport unit positioned on the downstream side in the transport direction and substantially vertically above. In this paper feeding apparatus, a pair of linear guide members is provided between the first conveying means and the second conveying means, and a paper feeding apparatus that conveys a sheet by guiding the linear guide members 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. In addition, the linear guide member is installed in an oblique posture with a substantially intermediate angle so that the degree of bending at these two locations is approximately the same, so that it can be conveyed during the 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.

The above-described conventional sheet conveying apparatus shown in FIG. 16 and first and second conveying means configured in substantially the same manner as Japanese Patent Application Laid-Open No. 2004-338923 (Patent Document 1) have A reversing guide member having an inclined surface reaching the second transporting means is provided between the second transporting means and the reversing guide member is configured to move toward the second transporting means. A paper device is known (see, for example, Patent Document 2).
According to this paper feeding device, when the rear end of the sheet comes into contact with the reverse guide member, the reverse guide member is displaced in a direction substantially the same as the direction in which the rear end of the paper 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 merge into one common conveyance path. And at least the conveyance path provided in the sheet accommodation means that accommodates the highly rigid sheet has a different radius of curvature of the first curvature part 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 an ordinary sheet when passing on the first curvature portion having a large curvature radius while traveling on the transport path. In contrast, since the sheet is continuously curved and sufficiently advanced as compared with the normal sheet, the resistance during the 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.

However, in the conventional sheet conveying apparatus shown in FIGS. 16 to 20 and the sheet conveying apparatus described in Patent Document 1, since the fixing member is arranged for guiding the sheet to be conveyed, the conveying which is a moving body. The speed difference between the sheet to be fixed and the fixed guide member is not eliminated, and a resistance that acts in a direction that hinders the conveyance of the sheet is always generated between the two regardless of the shape and installation posture of the guide member. Therefore, there is a problem that it becomes a transport 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 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 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.

  Further, as described in Patent Document 3, even in a configuration in which a dedicated conveyance path with a predetermined large radius of curvature is provided, the sheet traveling on the dedicated conveyance path is gently curved, and the sheet receives from the conveyance path. Even if the resistance is reduced, a transfer 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.

  In addition, as described in Patent Document 4, in a configuration in which a movable member such as a roller is provided at a predetermined position in the inner conveyance path portion in the direction change portion of the conveyance path, the sheet is moved by the inner roller in the conveyance process. Even if the frictional resistance between the two in the state where the middle part between the front and rear ends is supported can be particularly effectively reduced, the outer conveyance path in the front and rear state in which such a state occurs, that is, in the direction change portion thereof There is a lack of consideration for the conveyance load when the portion and the sheet are in contact with each other, and there is no particular mention of the behavior of the sheet leading edge or 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 present invention provides a second sheet conveying direction in which the sheet conveyed by the first conveying unit is conveyed in a second sheet conveying direction different from the first sheet conveying direction with a simple and low-cost configuration while saving space . This solves problems such as conveyance failure and jamming when a sheet, particularly a sheet having a relatively high rigidity, is conveyed to the second conveying means, and the leading edge of the sheet is stably directed toward the clamping portion of the second conveying means. sheet conveying apparatus capable of conveying a smooth, shall be the main object to provide an image reading apparatus and an image forming apparatus having the same.

  In order to solve the above-mentioned problems and achieve the above-mentioned object, the present inventors conducted tests and the like described in the following embodiments and examples, etc. In particular, as a simple configuration that can transport relatively rigid sheets such as cardboard and envelopes without causing poor transport or jamming, it came to the idea of a simple configuration called a moving guide. Various belt conveying means having the simplest configuration as a means have been devised and put to 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 in the first sheet conveying direction, and a first conveying unit that is disposed downstream of the first conveying unit in the first sheet conveying direction. a second conveying means for conveying the sheet conveyed in a different second sheet conveying direction the first sheet conveying direction, the second conveying means, conveying a second first conveying means Rotating and driving means disposed in the inner direction of the sheet conveying path formed between the rotating means and the outer periphery of the sheet conveying path and driven in contact with the rotating and conveying means. Belt conveying means for conveying the sheet by rotating, and is disposed in the inner direction of the sheet conveying path formed between the first conveying means and the second conveying means, and the first conveying Sheet conveyance from the first to the second conveying means An inner guide member having a curved portion forming a path, and a sheet conveying path formed between the first conveying means and the second conveying means, and arranged from the first conveying means to the outer direction. A sheet conveying device including an outer guide member that forms a sheet conveying path leading to the belt conveying unit, wherein the belt conveying unit holds the belt and the belt so that the belt can run. A first belt holding and rotating member arranged on the most downstream side in the second sheet conveying direction, and arranged on the most upstream side in the second sheet conveying direction so as to be able to run around the belt. A second belt holding and rotating member, and a leading end of the sheet is in contact with a conveying surface of the belt excluding the belt portion held by the first belt holding and rotating member and the second belt holding and rotating member. Arrange to do The axial center of the second belt holding rotating member is above the lower end of the rotating member provided on the outer periphery of the first conveying means, and is downstream of the outer guide member in the first sheet conveying direction. The rotary transport driving means disposed so as to be positioned below the end portion and abutting the first belt holding rotary member via the belt is configured to guide the inner contour within a cross section in which the rotary transport drive means rotates. it characterized in that it is arranged so as to overlap with the curved portion of the member.

According to a second aspect of the invention, the sheet conveying apparatus according to claim 1, wherein the belt conveying means, the leading end portion of the sheet, are arranged to enter with a rush acute angle with respect to the conveying surface of the belt It is characterized by being.

According to a third aspect of the present invention, in the sheet conveying apparatus according to the first or second aspect , the width of the belt in the sheet width direction orthogonal to the first sheet conveying direction of the first conveying means is the sheet width to be conveyed. It is characterized by substantially the same.

A fourth aspect of the present invention is the sheet conveying apparatus according to any one of the first to third aspects, further comprising a contact member that contacts the belt, wherein the contact member is a rear end of the conveyed sheet. Is arranged at a location different from the location in contact with the belt conveying surface.

According to a fifth aspect of the present invention, in the sheet conveying apparatus according to any one of the first to fourth aspects, the outer diameter of the first belt holding rotating member is larger than that of the second belt holding rotating member. It is characterized by that.

According to a sixth aspect of the present invention, in the sheet conveying apparatus according to any one of the first to fifth aspects, the first conveying unit separates the sheet into a single sheet and conveys the sheet toward the second conveying unit. A sheet transporting path from the sheet separating mechanism to the belt transporting unit, the sheet transporting mechanism having a sheet separating mechanism having a sheet feeding rotating member and a separating member in contact with the sheet feeding rotating member. At least one guide member of the outer shell that forms the plane, and a plane defined by the contact points of the sheet feeding rotation member and the separation member and a guide surface of the guide member of the outer shell are set in a substantially parallel relationship It is characterized by being.

The invention according to claim 7 is the sheet conveying apparatus according to any one of claims 1 to 6 , wherein the first conveying unit is a conveying unit that forms a nipping portion for nipping and conveying the sheet. At least a part of the inner guide member is provided outside a line segment connecting the center of the sandwiching part of the first transport unit and the center of the sandwiching part of the second transport unit and the belt transport unit. It is characterized by being.

The invention according to claim 8 is the sheet conveying apparatus according to any one of claims 1 to 7 , wherein a sheet having a metric basis weight of 80 to 300 g / m ² is conveyed from the first conveying means to the second conveying means. It is possible to convey to a clamping part between the means and the belt conveying means .

The invention according to claim 9 is the sheet conveying apparatus according to any one of claims 1 to 8 , wherein the sum of the sheet conveying force by the first conveying unit and the sheet conveying force by the belt conveying unit is It is larger than the sum of sheet conveyance loads in the inner guide member and the outer guide member.

According to a tenth aspect of the present invention, there is provided an image reading apparatus comprising the sheet conveying apparatus according to any one of the first to ninth aspects.

An eleventh aspect of the invention is an image forming apparatus comprising the sheet conveying device according to any one of the first to ninth aspects and / or the image reading device according to the tenth aspect.

According to the present invention, the above configuration can solve the above problems and provide a novel sheet conveying device, image reading device, and image forming apparatus. By way of specific effects for each invention 請 Motomeko described is as follows.
According to the invention of claim 1 Symbol placement, the above configuration, can be miniaturized devices, while conveying the sheet by the first transfer means, when the leading end of the sheet is conveyed by the belt conveying unit, the belt By obtaining a stable and appropriate elastic displacement / deformation state, the leading edge of the sheet can be stably and smoothly conveyed toward the clamping portion of the second conveying means.

According to the second aspect of the present invention, the belt conveying means is arranged so that the leading edge of the sheet enters with an acute angle of incidence with respect to the conveying surface of the belt. Regardless, the leading edge of the sheet can be brought into stable and reliable contact with the conveying surface of the belt.

According to the third aspect of the present invention, the belt conveying means is configured such that the width of the belt in the sheet width direction orthogonal to the first sheet conveying direction of the first conveying means is substantially the same as the width of the conveyed sheet. On the other hand, the sheet can always contact over the entire width of the sheet, and the contact area between the two can be ensured as much as possible. Along with this, the propulsive force that advances in the sheet conveying direction that can be supplied to the sheet from the belt conveying means can also transmit the maximum possible force, so the sheet conveying device avoids conveyance errors and jams, etc. Thus, an appropriate sheet conveying operation can be performed more reliably and stably.

According to the fourth aspect of the present invention, since the abutting member is disposed at a position different from the position where the trailing edge of the conveyed sheet is in contact with the conveying surface of the belt, the trailing edge of the sheet being conveyed is the belt. Even if it comes into contact with the conveyance surface, it becomes possible to allow elastic deformation of the belt portion where the rear end of the sheet is in contact. Therefore, even if the rear end of the sheet comes into contact with the belt, the rear end of the sheet is in contact. Without causing the contact member to prevent deformation of the belt portion, the impact caused by the collision can be sufficiently deformed and absorbed and relaxed by the belt, and the generated shocking noise (sudden sneak) can be suppressed.

According to the fifth aspect of the present invention, since the outer diameter of the first belt holding and rotating member is larger than that of the second belt holding and rotating member, the belt length can be shortened, and the rotation conveyance driving means and The sliding resistance can be reduced.

According to the invention of claim 6 , it is possible to further reduce the load due to the sheet conveyance in the sheet separation mechanism, and to suppress the generation of abnormal noise such as a splash sound when conveying a relatively rigid sheet such as cardboard, It becomes possible to further effectively reduce the sheet conveying sound. That is, at least one outer guide member that forms a sheet conveyance path from the sheet separation mechanism to the belt conveyance unit, and a plane defined by the contact between the sheet feeding rotation member and the separation member, and the guide member Since the guide surface of the outer guide member arranged in the outer direction of the sheet conveying path is set in a substantially parallel relationship, the plane defined by the contact of the sheet separating mechanism is separated from the sheet separating mechanism. The sheet to be emitted does not need to be changed or deformed in the sheet thickness direction by the outer guide member in the outer direction of the sheet conveyance path. For this reason, the resistance received by the sheet in progress on the sheet conveyance path from the outer guide member can be kept to the minimum necessary for maintaining the path of the sheet. On the other hand, the guide surface of the outer guide member arranged in the outer direction of the sheet conveying path of the sheet conveying path from the sheet separating mechanism until the sheet reaches the belt conveying means has a step that causes abnormal noise. No need to wake up.

According to the seventh aspect of the present invention, with the above configuration, the sheet conveying force is supplemented by the belt conveying means against the load at the time of conveying the sheet by the inner guide member. Even if the sheet fluctuates in the inner direction of the sheet conveyance path, it is possible to reliably guide the sheet, and it is possible to stably convey a sheet having high rigidity such as cardboard.

According to the invention described in claim 8 , with the above configuration, it is possible to provide a sheet conveying apparatus excellent in sheet type (paper type) compatibility from a relatively low rigidity sheet to a relatively high rigidity sheet. .

According to the ninth aspect of the present invention , not only the sheet conveying force by the first conveying means but also the sheet conveying force by the belt conveying means is added to the inner guide member and the outer guide member. It becomes possible to convey the sheet against a sheet conveyance load due to contact with the surface. Thereby, since the sheet conveyance load can be reduced, even a sheet having high rigidity such as cardboard can be stably conveyed.

According to a tenth aspect of the present invention, there is provided an image reading apparatus having the sheet conveying apparatus according to any one of the first to ninth aspects, whereby the sheet according to any one of the first to ninth aspects. Since the sheet transported by the transport device is a document, it is possible to obtain at least the effects of the first to ninth aspects in which the sheet (document) transport performance is improved, and the document sheet type (paper type) is compatible. Ru can be provided to achieve superior image reading apparatus.

According to an eleventh aspect of the present invention, the image forming apparatus includes the sheet conveying device according to any one of the first to ninth aspects and / or the image reading device according to the tenth aspect. Accordingly, as the transport object, whereas either a sheet or document, or for both, at least a sheet and / or the claims 1 improved the conveying performance of the original sheet can be obtained effects such as 9, sheet type (Paper type) An image forming apparatus with excellent compatibility can be realized and provided.

1 is a schematic front view illustrating an overall configuration of a sheet conveying apparatus and an image forming apparatus according to a first embodiment to which a sheet conveying apparatus and an image forming apparatus of the present invention are applied. FIG. 3 is a diagram illustrating the paper conveyance device according to the first embodiment and a paper feed tray stage around the paper conveyance device, and is an enlarged cross-sectional view of a main part illustrating an operation state in which the leading edge of the paper reaches the belt conveyance unit. FIG. 6 is an enlarged cross-sectional view of a main part showing an operation state immediately before the leading end of the sheet reaches the nip portion of the second conveying unit in the sheet conveying apparatus of the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of the sheet transport device for explaining the first embodiment and Example 1. It is a graph for demonstrating the test result regarding the dispersion | variation in paper type conveyance time of Example 1 in 1st Embodiment. A diagram showing a sheet conveying equipment of Example 1, (a) is an example in which the belt conveying means to the first conveying means, (b), the first, both means of the second transport means (C) is an example in which the belt conveying means is provided separately from the first and second conveying means. FIG. 9 is a schematic cross-sectional view illustrating a paper feed tray stage in which sheets are stacked and stored, and a sheet conveying device provided for the tray stage, according to Reference Example 2 of the present invention. FIG. 10 is a schematic enlarged cross-sectional view mainly showing the sheet conveying apparatus in a state where the leading end of the sheet reaches the belt conveying unit in the sheet conveying apparatus of Reference Example 2 ; FIG. 10 is a schematic enlarged cross-sectional view mainly showing the sheet conveying apparatus in a state immediately before the leading end of the sheet reaches the nip portion (clamping portion) of the second conveying unit in the sheet conveying apparatus of Reference Example 2 ; FIG. 5 is a schematic enlarged cross-sectional view showing a second embodiment to which the sheet conveying apparatus of the present invention is applied and mainly showing the sheet conveying apparatus. FIG. 9 is a schematic enlarged cross-sectional view showing a third embodiment to which the sheet conveying apparatus of the present invention is applied and mainly showing the sheet conveying apparatus. FIG. 10 is a partially enlarged cross-sectional view mainly showing an outline of a guide member provided in a direction of a conveyance path in the paper conveyance device according to the third embodiment . FIG. 9 is a partially enlarged cross-sectional view mainly showing a guide member in a direction of a conveyance path between a first conveyance unit and a second conveyance unit in the sheet conveyance device according to a third embodiment . FIG. 10 is a schematic enlarged cross-sectional view showing a reference example 3 of the present invention and mainly showing a paper conveying device. FIG. 9 is a schematic enlarged cross-sectional view showing a reference example 4 of the present invention and mainly showing a sheet conveying device. FIG. 10 is a schematic enlarged cross-sectional view mainly showing a sheet conveying apparatus having a conventional configuration. FIG. 10 is a schematic diagram illustrating a conventional paper transport device and illustrating the occurrence of abnormal noise due to a step between a paper stacking surface and a paper feed tray in a paper transport process. FIG. 9 is a schematic diagram for illustrating generation of abnormal noise due to a step between a sheet feeding tray and an outer guide member adjacent to the sheet feeding tray in a sheet conveying process, showing a sheet conveying apparatus having a conventional configuration. FIG. 9 is a schematic diagram illustrating a conventional paper conveyance device and illustrating the occurrence of abnormal noise due to a step between an outer guide member and an outer guide member adjacent thereto in a paper conveyance process. FIG. 9 is a schematic diagram illustrating a conventional paper conveyance device and illustrating an increase in conveyance load due to an inner guide member in a paper conveyance process. 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. 6 is a schematic enlarged cross-sectional view showing an example in which a low-friction treatment, a low-friction member is attached, or a low-friction member is used on the curved guide member of the paper transport device.

DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the drawings. Constituent elements such as members and components having the same functions and shapes in the embodiments, modifications, examples, and the like 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.
In the “Mode for Carrying Out the Invention” column, a modification of the first embodiment will be referred to as “Reference Example 1”, a second embodiment as “Reference Example 2”, and a third embodiment. "Second embodiment", fourth embodiment "third embodiment", fifth embodiment "reference example 3", sixth embodiment "reference example 4" , And shall be read as such.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic front view showing an overall configuration of an image forming apparatus equipped with a sheet conveying apparatus according to a first embodiment of a sheet conveying apparatus of the present invention and an image forming apparatus having the sheet conveying apparatus. FIG. FIG. 3 is an enlarged view showing a paper feeding device installed at a predetermined location in the image forming apparatus and a paper conveying device attached to a paper storage stage where the paper feeding device is located. FIG. 3 is an enlarged view mainly showing the vicinity of the paper conveying device. FIG.

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 the document image information to the image forming apparatus main body 2. Have.
A paper discharge tray 9 that discharges and stacks paper that has passed through the image forming apparatus main body 2 is installed so as to form a space above the image forming apparatus main body 2 and below the document reading device 4. A sheet transport path R1 (hereinafter also referred to as “transport path R1”) is formed as a sheet transport path (sheet transport path) for moving the sheet S from the apparatus 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, so that the transfer belt 17 is in contact with the surface of the photoconductor 10A and the transfer belt 17. The position is set. 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 one or both of the configurations of a rotating brush that rotates following the rotation of 10A, and removes toner, foreign matter, etc. 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 this 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 device 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 housed. 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.
In the document reading device 4, a document pressing plate 58 configured to be openable and closable between a closed position that covers the contact glass 57 and an open position that opens 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 of the original pressing plate 58 is supported on the upper surface of the reading apparatus main body 4A by a hinge (not shown) so as to be 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 storing the automatically or manually selected sheet S 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 conveying roller or the like on the conveying 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. Stops at 21.
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. 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.

Next, a characteristic configuration of the sheet transport device 5 according to the first embodiment 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 sheet feed tray 51 in the sheet feeder 3 shown in FIG. 1. One sheet S is pulled out from the sheet S, the sheet conveying direction (sheet conveying 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 transport means (hereinafter referred to as “second transport means”) 7 for transporting the paper S transported by the first transport means 6 in a paper transport direction different from the paper transport direction of the first transport 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 rotation member pair is composed of two conveying rotation members disposed opposite to the conveying belt 82, and one of the second conveying rotation member pairs includes a conveying belt 82 that contacts the paper S. The belt conveying means 8 (movement guide means), and the conveying surface 82a, which is a belt running surface formed on the conveying belt 82 in the belt conveying means 8, includes a first conveying means 6 and a second conveying means 7. It is characterized in that it is arranged at a position deviating in the outline direction of the first conveyance path A as a sheet conveyance path (sheet conveyance path) formed between the two.

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) 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 roller-like pulley 83 and a roller-like pulley as a pair of belt holding and rotating members that hold the conveying belt 82 so as to run. The pulley 84 is mainly comprised.
In the belt conveyance unit 8, the leading edge of the sheet S conveyed by the first conveyance unit 6 abuts on the conveyance surface 82 a of the conveyance belt 82 excluding the portion of the conveyance belt 82 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 (the center of the pulley shaft 84a) is located above the lower end position of the reverse roller 62 and below the height of the downstream end 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 examples and embodiments described later.

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 disposing the belt conveying means 8 in this manner, 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 reliably 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 end portion 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, the contact belt is bent in the direction opposite to the traveling direction of the conveyor belt 82 or repelled. The same applies to examples and embodiments described later.

The paper feed trays 51 of each stage in the paper feed device 3 are formed in a substantially flat box shape having 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 of FIG. The free end portion is configured to be swingable within the sheet 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 its base end is pivotable within the recess within a predetermined angular range, that is, is swingable, 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 portion 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 in the figure of the bottom plate 50. 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) arranged 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 the present embodiment, the image forming apparatus is an in-body discharge type image forming apparatus, but by providing the movement guide means, the conveyance path can be conveyed with the same curvature as the conventional one or less, so the width direction of the apparatus It is possible to prevent the advantage of the in-body discharge type from being diminished without increasing the size.

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 the present embodiment, for example, an FRR (Feed Reverse Roller) paper feeding method, which is a reverse separation method, is used as a paper feeding method (sheet feeding method) that separates and feeds stacked sheets S into one sheet without double feeding. Is adopted. 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 driven 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 can be supported in the same manner as the pickup roller 60. 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. Also, 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 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. Therefore, 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 transport force supplied from the reverse roller 62 to the paper S that is in contact with the reverse roller 62 ensures that the transport force in the reverse direction is sufficient to return the paper 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 to the paper S from the feed roller 61 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.
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 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 opening / closing guide 79 is provided with a hinge fulcrum shaft (not shown) below the housing 80 so that the user can easily handle jams, jams, and the like in the first conveyance path A and a vertical conveyance path extending substantially vertically upward. ), The conveyor belt 82 can be freely opened and closed so that the grip belt 81 can contact and separate.
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.

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. That is, the linear belt running surface (conveying surface 82 a) of the conveying belt 82 stretched between these pulleys 83 and 84 and formed between the pulleys 83 and 84 is sent out by the first conveying means 6. The leading edge of the sheet S is always disposed at a position where it comes into contact. In this way, 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 conveyance 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, and used on a sheet 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 conveyance 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.

  As will be described later with reference to FIGS. 21 and 22, the rotational drive shaft 81a of the grip roller 81 is provided with a rotational drive source such as an electric motor dedicated for the rotational drive of the grip roller 81. It is connected via a driving force transmission means such as. 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.

As shown in FIGS. 21 and 22, the drive mechanism 22 includes a paper feed motor 23 including a stepping motor as a single drive source / 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 the present embodiment, the paper conveyance device 5 is compact and space-saving, that is, the first conveyance path A is a curvature portion having a relatively small radius of curvature as illustrated in Example 1 described later. In view of the configuration, 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. 21, 62b represents what was demonstrated as the torque limiter which is not shown in the example shown in FIGS.

In the embodiment shown in FIGS. 1 to 4, the rotational drive relationship between the pickup roller 60 and the feed roller 61 has been simply described. In practice, however, as shown in an enlarged view in FIG. The shaft 61a is connected to a shaft 61a by a pickup arm member 64, and the pickup roller 60 is not shown so that the pickup swings and displaces through the pickup arm member 64 about the shaft 61a on the feed roller 61 side. It is driven by a combination of a solenoid and a spring.
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, but here the grip roller 81 is a rotation 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.
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, better to drive the grip roller 81 side from driving the conveyor belt 82 side, Ru can reduce variations in the linear speed of the conveyor belt 82.

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 a sheet (sheet) S having a relatively low rigidity, is used except for a sheet S (sheet) having a relatively high rigidity such as thick paper or an envelope. .

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 belt S is gradually curved from the leading end side of the sheet S along with the movement of the belt conveying surface in the sheet conveying direction due to the traveling of the conveying belt 82 in the direction of arrow a, and 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. Give it to the paper S to make up for it. 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, since the conveyance surface 82a of the conveyance belt 82 is continuously extended as it is to the nipping portion (nip portion) of the second conveyance means 7, 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 sheet S toward the second transport means 7.
In the present embodiment, the belt conveying unit 8 as the movement guiding unit moves and guides the conveyance direction of the sheet S in the direction toward the nipping portion (nip portion) of the second conveying unit 7 by the conveying belt 82. It also has a function to

  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 A 40 degrees Friction coefficient of conveyance belt 82: 2.6 (for paper)
Conveying belt 82 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 shown in FIG. 5, when the metric basis weight is 256 g / m ² or more as the paper type, the conveyance time is long in the conventional method and the slip of the paper is large. 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.
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 indicates 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” indicated by a cross indicates that the conveyance is good means that 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 cannot 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 paper passing / conveying situation, when the metric basis weight is 256 g / m ² or more in the conventional method, the paper becomes stiff and difficult to bend along the curved paper conveying path. Referring to FIGS. 1 to 3, 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 against 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 A 40-60 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 it is high due to the conveyance load in the sheet conveyance path (conveyance path) from the first conveyance unit 6 to the second conveyance unit 7. In contrast to the rigid 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 excellent in paper type. 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 the conveyance propulsion force (or the sheet conveyance force by the first conveyance means 6 (sheet conveyance force) is added to the sheet conveyance force by the second conveyance means 7 from the first conveyance means 6 to the first conveyance means 6. 2) The sheet can be moved downstream because it can counter the conveyance load on the conveyance path to the conveyance means 7. 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. In addition, it 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 embodiment)
FIG. 6 shows a modification of the first embodiment.
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 at the first conveying means 6 and the second conveying means 7, both sides may be belt conveying means 8, 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 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 conveying belt 82 is driven to rotate and rotate clockwise 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 of this. In 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 conveyor belt 82 may be exhibited.
Therefore, any of the above-described modifications can obtain at least the same effects as those of the first embodiment described above.
(Second Embodiment)

  A second embodiment of the present invention 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 particularly described, configurations not described in the present embodiment, that is, a sheet transport device, other configurations, and operations thereof are the same as those of the sheet transport device 5 of the first embodiment illustrated in FIGS.

  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 A point having the second conveyance path B, and a first conveyance path A and a second conveyance path B merge at the upstream of the second conveyance means 7 (hereinafter also referred to as “merging conveyance path”). The main difference is that the belt conveying means 8 of the second conveying rotating member pair is disposed so as to be dislocated in the outline direction of the merged conveying path of the first and second conveying paths A and B. 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 3 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 edge of the sheet S conveyed on the first conveying path A by the first conveying means 6 is always in contact with the belt conveying surface, and is conveyed on the second conveying path B by an unillustrated conveying means. The sheet S is not prevented from reaching the second conveying 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.

  Note that the second embodiment 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. Similarly to the modification of the first embodiment shown, the belt conveying means 8 that is independent of the second conveying roller pair 81 and 83 may be provided.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component and member same as 2nd Embodiment, and description is abbreviate | omitted or simplified. Although not particularly described, the configuration not described in the third embodiment, that is, the sheet transport apparatus and other configurations and operations thereof are the same as those of the sheet transport apparatus 5 of the second embodiment shown in FIGS. is there.

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 embodiment, the belt conveying means 8 includes a pair of roller type pulleys 83 and 84 with the conveying belt 82 stretched, and a grip roller. A contact member such as a tension roller 85 as a member that contacts the conveyance belt 82 other than 81 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 the third embodiment, 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 guided by the guide member 71. Even when the support belt is separated from the support and collides with the conveyance surface 82a of the conveyance belt 82, the conveyance surface 82a of the conveyance belt 82 can be sufficiently elastically deformed so as to be displaced in the collision direction as shown by a two-dot chain line in the figure. Thus, the impact of the trailing edge Se of the paper S can be absorbed, so that 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 present embodiment, the rear end Se of the transported paper S is in contact with 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 as an abutting member for supporting this is arranged, when the sheet S is conveyed in a predetermined curve, the rear end Se of the sheet S is set to the nip of the first conveying unit 6. Or the guide member 71, and when it collides with the conveyance surface 82 a, the collision belt 82 can be sufficiently elastically bent to absorb the impact. , The sudden sound generated by the collision can be suppressed. 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 end Se of the sheet S contacts, and the trailing edge of the sheet S is prevented. The conveyance 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 trailing 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, so that the user's discomfort is eliminated, and quietness that avoids the misconception that a failure has occurred is obtained, and the usability of the apparatus is improved. 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 embodiment 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 embodiment is opposed to a predetermined one like the configuration shown in FIG. 10. Tension is applied only to the non-conveying surface side that does not face the first conveying means 6 out of two substantially linear belt running surfaces that are stretched around the pair of arranged pulleys 83 and 84 and formed on the conveying belt 82. Without being limited to the arrangement of the rollers 85, one of the two belt running surfaces including the facing conveying surface side is selected, and the belt running surface is selected at any location on the selected belt running surface. A roller 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 embodiment, a tension roller is provided to ensure tension by pressing and urging outward from the inside of the stretched belt after securing the predetermined position. However, conversely, a configuration may be employed in which a tension roller is provided for pressing and urging the belt inward from the outside to ensure tension.
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 paper 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.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component and member same as 2nd Embodiment shown in FIGS. 7-9, and 3rd Embodiment shown in FIG. 10, and description is abbreviate | omitted or simplified. To. Although not particularly described, configurations not described in the fourth embodiment, that is, a sheet transport device, other configurations, and operations thereof are the same as those in the third embodiment.

  In the fourth embodiment, it is possible to reduce the load from the fixed guide member that forms the conveyance path between these two means in the paper conveyance path from the first conveyance means to the belt conveyance means, and In this case, the sheet conveying noise is reduced by suppressing the splash sound generated when the rear end of the sheet is in contact with the fixed guide member. In addition to this, it is possible to reduce the load from the fixed guide member in the paper transport path from the paper storage means to the first transport means, and the rear end of the paper impacts the fixed guide member. In order not to touch the paper, the noise is suppressed and the paper conveyance sound is reduced.

  As shown in FIGS. 11 to 13, the paper transport device 5 according to the fourth embodiment is configured so that when the topmost paper S stacked on the bottom plate 50 starts to be transported, From the starting position of the leading edge of the paper, the paper travels substantially straight in the section from this starting point to the arrival point where the leading edge of the paper reaches the first conveying means 6. Then, with the position of the leading edge of the sheet being conveyed as a reference, the position where the leading edge of the sheet is separated from the first conveying means 6 is set as a starting point, and the leading edge of the sheet from the starting point to the belt conveying means 8. In the section between the reaching points, the paper advances substantially straight. Further, in the same section, the leading edge of the sheet is fixed by the fixed guide member 90 disposed in the inner direction of the sheet conveying path between the first conveying means 6 and the second conveying means 7. The first conveyance unit 6 and the second conveyance unit are prevented from being prevented from proceeding directly toward the nip portion, and at least after the leading edge of the sheet reaches the belt conveyance unit 8, the conveyance of the sheet advances. When the sheet is nipped and conveyed by the sheet 7, an intermediate portion between the nipping positions of both means on the sheet is prevented from being unnecessarily curved by the fixed guide member 90.

As shown in FIG. 11, in the paper transport device 5, a grip roller 81 is provided as a post-turn roller inside the turn on the downstream side of the paper turn portion in the sense of changing the paper traveling direction. A conveying belt 82 as the belt conveying means 8 is provided outside the turn so as to face the roller 81, and the conveying belt 82 has a belt running surface (conveying surface) as a first conveying roller pair upstream of the turn. The front end of the sheet is extended so as to contact with an acute angle of the entry angle θ so that it substantially intersects the traveling direction of the sheet when the unit 6 is conveyed alone.
In the paper conveyance path from the feed roller 61 as the upstream upstream roller in the turn section to the conveyance belt 82 which is the downstream belt, the paper conveyance path is formed and the paper is guided to the belt conveyance means 8. Paper guide members 93 and 91 as second guide members are arranged. Due to the shape of these sheet guide members (hereinafter also simply referred to as “guide members”) 93 and 91, the sheet S conveyed between the first conveying means 6 and the conveying belt 82 on the sheet conveying path is substantially straight. To be sent to. The leading edge of the sheet emitted from the first conveying means 6 reaches the belt running surface of the conveying belt 82 in the same advancing direction without changing the advancing direction in which the sheet is conveyed.

As shown more specifically in FIG. 12, the guide members 93 and 91 provided in the outline direction of the paper transport path are configured so as to have substantially the same plane with a shape and arrangement that does not have a turn, a curve or the like in the middle. ing.
Guide surfaces 93A and 91A for guiding sheets are formed on the guide members 93 and 91, respectively. Of the paper guide members that form the paper conveyance path from the first conveyance means 6 to the belt conveyance means 8, the guide surfaces 93A and 91A of several guide members 93 and 91 in the outer direction of the paper conveyance path are provided. The prescribed shapes are such that the guide surfaces 93A and 91A of the guide members 93 and 91 belong to substantially the same plane, and the gap distance between the adjacent guide surface end portions 93A and 91A is small by a predetermined amount. . That is, each guide surface 93A, 91A secures a gap in the left-right direction in the drawing in which the leading edge of the paper traveling in the paper conveyance direction and the trailing edge of the paper are not caught or dropped, and the paper conveyance is almost continuous. Is formed in a shape constituting a plane that can be regarded as a broken line (shown by broken lines in the figure), and the continuous plane is a contact point where the feed roller 61 and the reverse roller 62 as the separating member are in contact with each other. In addition, the plane other than the contact point is set in a substantially parallel relationship with the plane defined by taking into consideration the dimension of the thickness of the conveyed paper. As a result, until the leading edge of the paper leaves the first transport means 6 and reaches the belt transport means 8, the paper transported in the transport process is caused to advance straight and substantially straight.

  Therefore, even when the sheet is conveyed in a state where the sheet is in contact with the guide surfaces 93A and 91A of the guide members 93 and 91 in the section between the first conveying unit 6 and the conveying belt 82, the interval between them. Therefore, when the rear end of the sheet is transferred from the guide surface 93A to the guide surface 91A, the above-described squeaking noise is not generated, and conveyance of the sheet from the guide members 93 and 91 is performed. The resistance can be minimized, and the load from the fixed guide to the paper can be reduced.

  As described above, the first conveying means 6 composed of the feed roller 61 and the reverse roller 62 is a paper feed separation mechanism such as an FRR paper feed system as a sheet separation mechanism. Therefore, when the transport force of the feed roller 61 is relatively small and the transport load is large with respect to the paper transported by the paper feed separation mechanism, the paper slips and transports as designed. Since it is often impossible to feed paper at a speed (linear speed), for example, a reduction in copy productivity and a paper jam are likely to occur. More specifically, when the sheet conveyance load is large, slip occurs between the sheet and the feed roller 61 that is in contact with one sheet to be separated, even if the sheet can be separated into one sheet. Since one sheet of paper cannot be sent out at the exact conveyance speed as designed, the number of sheets conveyed per unit time decreases, leading to a decrease in productivity in image formation, or the sheet stops. Paper jams are likely to occur.

In contrast, in the fourth embodiment, the guide surfaces 93A and 91A of the guide members 93 and 91 are assumed to have no deformation action due to external force or gravity on the sheet itself, and the first conveying means 6 alone. Is formed so as to be in a substantially parallel relationship with a predetermined gap distance with respect to a virtual paper transport surface on which the paper transported in the above is traveling. Can solve all the problems.
In other words, the guide members 93 and 91 merely guide the sheet conveyed from the first conveying unit 6 so as to maintain the straight path, and may deform the sheet in any way. Since the traveling direction is not changed, the conveyance resistance is minimized. For this reason, it is possible to prevent the above-described decrease in productivity and paper jam.
Then, in the sheet conveyance process after the leading edge of the sheet reaches the conveyance belt 82, the guide of the guide member 91 that is the downstream guide member from the guide surface 93A of the guide member 93 that is the upstream guide member in the section. When the rear end of the sheet is transferred to the surface 91A, the guide surfaces 93A and 91A are formed so as to belong to the same plane so as to eliminate the step between the guide surface 93A and the guide surface 91A. Therefore, the contact of the trailing edge of the sheet with respect to both guide surfaces 93A and 91A can be maintained substantially continuously, and the trailing edge of the sheet is once separated from the guiding surface 93A at least to the extent that no squeak is generated. It is not necessary to make a shocking contact with.

On the other hand, as shown in FIG. 13, among the sheet guide members that form the sheet conveying path from the first conveying means 6 to the second conveying means 7, the fourth arranged in the inner direction of the sheet conveying path. The guide member 90 is in a state in which the first conveying means 6 and the second conveying means 7 both hold the paper, and the middle portion of the paper located between the means 6 and 7 extends substantially linearly. In this case, the guide member 90 is provided at a position retracted in the inner contour direction so that the guide member 90 itself does not contact with or slide on the intermediate portion of the sheet to cause a conveyance resistance that prevents the sheet from moving forward. ing.
The guide member 90 is a tangent indicated by a broken line in FIG. 13 that connects a tangent line between a feed roller 61 that is a roller disposed inside the turn in the first conveying unit 6 and a grip roller 81 that is a roller disposed inside the turn in the second conveying unit 7. It is provided on the inner side than α. As a result, in the paper transport process, the paper is fed without hitting the guide member 90 as an inner guide, so that the front end of the paper is emitted from the first transport means 6 and the rear end of the paper is transferred from the second transport means 7. In the process of transporting paper until it passes, it is possible to further reduce the load during transport of the paper, and it is possible to stably transport high rigidity and strength paper such as thick paper.

More specifically, the guide member 90 is formed in a plane that is translated diagonally left upward in the drawing by a predetermined gap distance from the tangent line α over the entire guide surface 90A formed on itself. Yes. In other words, the guide surface 90A occupies a position spaced apart from the tangent line α by a predetermined gap distance in the diagonally upper left direction in the drawing orthogonal to the paper transport direction over the entire area, and the tangent line. It is formed in a continuous plane substantially parallel to α.
Here, the sheet conveying apparatus having the conventional configuration shown in FIG. 20 will be described in comparison with that of the fourth embodiment. In the conventional paper transport apparatus shown in FIG. 20, after the leading edge of the paper S comes into contact with the guide member 72 forming the vertical guide 72a surface, the leading edge of the paper S is shown along the guide surface 72a in FIG. Is sent downstream in the paper transport direction shown as the upper side. At this time, as indicated by reference numerals Xa to Xd in FIG. 20, after the leading edge of the sheet reaches the upstream roller pair 105, the sheet S protrudes beyond the tangent line. The sheet hits the inner guide member 103, and the sheet is fed while being bent at this portion. However, when the sheet is bent inward as described above, the load of sheet conveyance increases. That is, a part of the sheet conveying force transmitted to the sheet from the upstream roller pair 105 as the first conveying unit and the downstream roller pair 106 as the first conveying unit is for bending the sheet in this way. It will be spent and not all will be used to advance the paper. As long as the sheet is bent by the inner guide member 103, the partial consumption of the sheet conveying force is continued without being released. Further, since the intermediate portion of the sheet is fed while sliding with the inner guide member 103, the load of the sheet conveyance is also increased. That is, since the intermediate portion of the sheet in contact with the inner guide is continuously deformed by the inner guide member 103 while being pressed and deformed, the contact pressure between the two increases, and the sliding resistance generated between the two increases. To do.

  On the other hand, in the present embodiment, as shown in FIG. 13, the guide surface 90A of the guide member 90 does not exceed the tangent line α, that is, away from the sheet conveyance path that is not in contact with the tangent line α. Since the sheet is formed so as to be substantially parallel to the tangent line α at the retracted position, it is possible to prevent an increase in the sheet conveyance load as described above. The guide member 90 according to the present embodiment has a path that is generally directed to the front end of the sheet that moves toward the nip portion of the second conveying unit 7 while performing a minimum guide function of preventing the sheet from deviating from the sheet conveying path. Bending or sliding an intermediate portion on the paper that is located between the location of the paper sandwiched by the first transport means 6 and the location of the paper sandwiched by the second transport means 7 No resistance is generated, and it is not necessary to generate any load on the conveyance.

11 and 12, in the present embodiment, the pickup roller 60 is a feeding rotation member that feeds the paper S to the first conveying means 6, the feed roller 61 is a sheet feeding rotation member, and the reverse roller 62 is separated. Each functions as a member.
Between the pickup roller 60 and the feed roller 61 on the paper transport path, the paper to be transported is sent substantially straight due to the paper guide shape outside the turn. That is, the sheet feeding direction by the feed roller 61 and the direction of the sheet conveyed from the pickup roller 60 to the feed roller 61 are set to belong to substantially the same plane.
Specifically, the position of the pickup roller 60, the shape of the paper guide surface 51A on the front surface of the paper feed tray 51 as the first guide member, and the shape of the guide member 93 as the second guide member are turned, curved, etc. The so-called flat surfaces are set so as to be substantially parallel to the sheet conveying surface defined by the pickup roller 60 and the feed roller 61. Yes. That is, as shown in FIG. 12, the line β perpendicular to the line connecting the rotation centers of the feed roller 61 and the reverse roller 62 and passing through the contact points of both the rollers 61 and 62 is loaded with the pickup roller 60. The guide surfaces 51A and 93A by the guide members from the pickup roller 60 to the feed roller 61 provided on substantially the same plane are substantially parallel to the contact line in contact with the uppermost sheet. It is provided to be in a relationship.

  In other words, among the guide members that form the paper transport path from the pickup roller 60 to the first transport means 6, the paper feed tray 51 and the guide member 93 are formed as the guide members in the outer direction of the paper transport path. All the guide surfaces 51A and 93A belong to substantially the same plane, and these guide surfaces 51A and 93A are a virtual single contact with the pickup roller 60 and the feed roller 61 used for paper conveyance. Is set so as to have a substantially parallel relationship with a predetermined gap distance.

Accordingly, all of the guide surfaces 51A and 93A formed by the sheet feeding tray 51 and the guide member 93 as fixed guide members arranged in the outer direction are defined as the sheet surface of the uppermost sheet in contact with the pickup roller 60. By forming a substantially continuous and identical plane that belongs to a virtual plane with the paper stacking surface extended, the above-mentioned step that causes the squeak noise is eliminated. In addition, the conveyance resistance received by the sheet conveyed from the guide surfaces 51A and 93A can be minimized.
On the other hand, even after the leading edge of the paper reaches the first conveying means 6 as the paper feed separating mechanism, the downstream portion of the paper that has not reached the first conveying means 6 is fixed in the outer guide direction. The conveyance resistance received from the member is reduced to the necessary minimum. For this reason, it is possible to prevent the above-described decrease in productivity and paper jam, and it is not necessary to reduce the paper separation performance and the transport performance due to the first transport means 6 alone.

  Note that, in the first conveying means 6 including the feed roller 61 and the reverse roller 62, the nip portion formed by the feed roller 61 and the reverse roller 62 in contact with each other is set on the above virtual single plane. . Accordingly, the paper transport direction defined by the pickup roller 60 and the feed roller 61 and the paper transport direction defined by the first transport means 6 substantially coincide with each other, and two virtual paper transports defined by these respectively. The surfaces are aligned on substantially the same plane. Therefore, the guide member 93 forms a sheet conveyance path in a section from the pickup roller 60 to the feed roller 61 as the first conveyance means 6 and is positioned as the guide member positioned in the outer direction, and the first It is a common member that is also used as a guide member that forms a paper conveyance path in the section from the feed roller 61 that is the conveyance means 6 to the belt conveyance means 8 and is positioned in the outer direction, and is aligned on the same plane. It is set so as to be substantially parallel to the two sheet conveyance surfaces. As a result, since the guide surface 93A is formed as a single flat surface, as a result, the paper started from the paper storage means and started to be conveyed has the leading edge of the paper kept in the general orientation of the paper. The belt travels straight and reaches the belt running surface of the belt conveying means 8.

  As described above, according to the paper transport device of the fourth embodiment, the outer direction of the paper transport path among the guide members that form the paper transport path in the section from the first transport means to the belt transport means. All the guide surfaces formed by several guide members located in the above form a substantially continuous flat surface that eliminates the step in the paper transport direction, so that the paper transported in the section is straight The conveyance resistance received from the guide member can be minimized, and at least the rear end of the sheet is brought into impact contact with any one of the guide members between the first conveyance unit and the belt conveyance unit. There can be no step and no collision noise is generated. For this reason, it is possible to prevent a conveyance failure such as a paper jam due to a step in the section, and it is possible to avoid occurrence of an abnormal noise as a conveyance operation sound of the sheet conveyance apparatus due to the step in the section. In particular, even when transporting highly rigid paper such as thick paper, it is possible to sufficiently prevent poor transport in the above section and abnormal noise due to the trailing edge of the paper, and the paper transport device supports that paper type. Performance can be improved.

  The guide member in the inner direction of the sheet conveyance path disposed between the first conveyance unit and the second conveyance unit is formed between the outermost shapes related to the respective sheet conveyances in the first conveyance unit and the second conveyance unit. Is arranged so as not to exceed a predetermined tangent line, it is possible to prevent the occurrence of conveyance resistance due to the guide member, and at least reduce the load on the first conveyance means, thereby enabling stable sheet conveyance. it can. The guide surface formed by the guide member in the inner direction of the sheet conveyance path is from the sheet conveyance path with respect to a virtual single plane where both the first conveyance unit and the second conveyance unit used for sheet conveyance are in contact with each other. It is located in a direction away from it and is provided in a non-contact manner and substantially parallel to this single plane. Accordingly, in the paper conveyance process from the time when the leading edge of the paper passes through the first conveying means to the time when the trailing edge of the paper passes through the second conveying means, the leading edge of the paper hits the guide member in the inner direction of the conveyance path. The intermediate portion between the leading end of the lever and the portion sandwiched between the first conveying means does not need to be deformed, and particularly when both the conveying means sandwich the sheet, Since the intermediate portion between the location held by the first conveying means and the location held by the second conveying means can convey the sheet without contacting the guide member in the inner direction of the sheet conveying path between both conveying means. In addition, friction resistance based on the contact of the intermediate portion with the guide member can be eliminated and transfer resistance can be eliminated, and the guide member prevents deformation of the intermediate portion and is converted into transfer resistance. Nothing at all It can be.

  In particular, even when a highly rigid sheet such as a cardboard having high resistance to deformation is conveyed, at least in the conveying process in which both the conveying means sandwich the highly rigid sheet, the highly rigid sheet is The guide member can be maintained in a non-contact manner, and the occurrence of the various conveyance resistances can be prevented. For this reason, it is possible to smoothly convey a sheet of high rigidity when both conveying means are sandwiched between them, and as a sheet conveying apparatus, it is possible to improve the paper type correspondence performance.

  Further, among the guide members that form the paper transport path in the section from the pickup roller to the first transport means, all the guide surfaces formed by several guide members located in the outer direction of the paper transport path are: Since a substantially continuous flat surface that eliminates a step in the transport direction is formed, the paper transported in the section advances straight, and the transport resistance received from the guide member can be minimized, and the pickup roller Between the first and second conveying means, at least the rear end of the paper can be free from any step that makes an impact contact with any one of the above-mentioned guide members, so that it is not necessary to generate a collision sound as a flying sound. For this reason, the conveyance failure resulting from the level | step difference in the said area and generation | occurrence | production of unusual noise can be prevented. In particular, even when a highly rigid sheet such as a thick sheet is conveyed, it is possible to sufficiently prevent the occurrence of conveyance failure and abnormal noise in the section, and the sheet conveying apparatus can improve the paper type correspondence performance.

In particular, in the paper transport device of the present embodiment, the paper is fed so that the leading edge of the paper reaches the flat belt running surface of the belt transport means without deforming the paper in the thickness direction from the paper feed position. Since it is conveyed in a straight line consistently, the ability of the belt conveying means can be maximized, and the paper conveying performance can be improved.
That is, in the paper transporting process of the paper transporting device, once the paper is deformed in the thickness direction and the traveling direction is changed to a predetermined direction, the fixed outer direction in which the paper transport path is formed and The guide member in the inner contour direction is mainly involved in the belt conveying means with little involvement. At least the outer guide member is arranged in a position that ensures only the straight direction until the leading edge of the paper reaches the belt running surface and does not hinder the change or deformation of the paper by the belt conveying means. In addition, when the paper is deformed so as to bend to change the paper traveling direction, the leading edge of the paper is always separated from the guide member in the outer direction, and the rear edge side of the paper leading edge. Therefore, the conveyance resistance generated between the guide member in the outer direction and the sheet is kept to a minimum and is gradually reduced. The guide function of changing the direction by the belt conveying means as an active guide member is sufficiently exhibited, and the operation effect is obtained. At the same time, once the sheet starts to deform, the guide member in the inner direction located inside the deformation direction is provided in a retracted position not hindering the deformation. It is not necessary to generate a conveyance resistance due to the guide member in the contour direction. These are particularly advantageous for preventing poor transport when transporting highly rigid paper, such as cardboard, that has high resistance to deformation, and the paper transport device can be expanded in its range of paper types. , Can improve the transport performance.

  In the description of the paper conveying apparatus of the fourth embodiment, the description and illustration of the contact member attached to the belt conveying means described in the third embodiment shown in FIG. 10 are omitted. As in the third embodiment, an abutting member may be provided, and this is the same in the following embodiments. In the fourth embodiment, the example of the sheet conveying apparatus having the second conveying path has been described. However, the present invention may be applied to a sheet conveying apparatus having no second conveying path. The same applies to the embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component and member same as said 4th Embodiment, and description is abbreviate | omitted or simplified. Although not particularly described, the configuration not described in the fifth embodiment, that is, the sheet conveying device, other configurations, and the operation thereof are the same as those in the fourth embodiment.

  As shown in FIG. 14, the paper transport device 5 according to the fifth embodiment has a turn between the feed roller 61 and the belt with respect to the paper guide shape outside the turn between the pickup roller 60 and the feed roller 61. The outer paper guide shape is not provided on the same surface, that is, on the non-identical surface.

  More specifically, as shown in the figure, the guide surface 95A formed corresponding to the section between the pickup roller 60 and the feed roller 61 in the transport guide member 95 arranged in the outer direction of the paper transport path. In the same manner as in the fourth embodiment described above, the two rollers 60, 61 used for paper conveyance are formed on a surface substantially parallel to a virtual plane in contact with each other, whereas the belt from the feed roller 61 to the belt is formed. The guide surface 95B formed corresponding to the section up to the conveying means 8 does not belong to a virtual plane extending from the guide surface 95A, and faces the vicinity of the nip portion of the second conveying means 7. The surface is formed to be a substantially flat inclined surface inclined upward at a predetermined angle. Note that the connection portion between the guide surface 95A and the guide surface 95B is located at a position that is biased to the downstream side of the sheet conveyance path by a predetermined amount in consideration of the radius of the feed roller 61 and the rigidity strength of various sheets to be conveyed. Is provided.

Therefore, the leading edge of the paper that has reached the nip portion of the feed roller 61 is substantially around the feed roller 61, and the contact with the fixed guide member is shifted from the guide surface 95A to the guide surface 95B, and the traveling direction thereof is inclined by a predetermined angle. In the angle diagram, the direction is changed to the diagonally right upward direction, that is, the direction is changed to the relatively gentle diagonally upward right direction. For this reason, the contact area on the sheet with respect to the feed roller 61 can be increased compared to the configuration in which the sheet is passed straightly in contact with the feed roller 61. A proper conveying force can be supplied from the feed roller 61 to the sheet. That is, in the configuration in which the sheet is passed in a straight line, the contact portion between the two becomes a substantially linear contact, whereas the orientation of the roller 61 is made to be involved in the vicinity of the feed roller 61 in this way. In the changed configuration, the sheet can be wound around the outer periphery of the feed roller 61 to some extent, and the contact portion between the two can be expanded in a substantially circumferential shape. Since the contact portion between the two is thus enlarged, the conveying force transmitted by frictional contact from the feed roller 61 to the paper is increased as the frictional contact area as the contact portion is increased.
In this way, until the belt conveyance means 8 is reached in the paper conveyance process after changing the traveling direction of the paper, that is, after changing the course, the paper is inclined upward so that the paper travels straight upward in the diagonally right direction. It is guided by the guide surface 95B of the surface.
By shifting from the guide surface 95A to the guide surface 95B, a sufficient conveying force can be supplied from the feed roller 61 to the sheet even when the amount of conveying force consumed for changing the sheet traveling direction is subtracted, and the course is once changed. Since the paper traveling in the section guided by the guide surface 95B goes straight again in the changed direction without changing the course again, the paper from the guide surface 95B with respect to the paper portion in progress in the section as described above. Transport resistance can be reduced.

  On the other hand, the trailing edge of the sheet transported in this way is not required to generate the above-described splash sound due to the impact contact with the transport guide member 95. That is, as the guide surface formed by the transport guide member 95, the guide surface 95A and the guide surface 95B are continuous, and between them, the support for the rear end of the paper is released even momentarily. Therefore, once the trailing edge of the paper comes into contact with the guide surface 95B, it is not necessary to leave the guide surface 95A and the guide surface 95B to such an extent that no sneak noise is generated.

  As described above, according to the paper transport device of the present embodiment, in addition to the effects substantially similar to those of the fourth embodiment described above, the traveling direction of the front end of the paper is changed to the first transport means. In the vicinity of the feed roller, a predetermined angle is changed so as to face the second conveying unit, and the sheet is linearly moved in the changed direction in the section from the feed roller to the belt conveying unit with the feed roller as a boundary. In addition, it is possible to minimize the conveyance resistance from the fixed guide to the sheet that travels from the feed roller to the belt conveyance unit after supplying a sufficient conveyance force to the sheet from the feed roller. As a result, even when transporting highly rigid and strong paper such as thick paper, abnormal sound generation and transport failure can be prevented, paper transport can be ensured, and paper transport performance can be improved.

On the other hand, as compared with the fourth embodiment, according to the fifth embodiment, at least the position where the leading edge of the paper reaches the belt conveying means of the second conveying means and contacts is detected by the second conveying means. It can be made to approach to a clamping part. In other words, the fourth embodiment is configured to reach the belt conveying means without changing the traveling direction of the paper emitted from the paper storage means, whereas in the fifth embodiment, Since the advancing direction is changed only once around the second conveying means so as to face the clamping portion of the second conveying means, the contact position of the leading edge of the paper on the belt conveying means is set to be higher than the former. 2 It can approach to the clamping part of a conveyance means. For this reason, for example, the front end of the paper and the rear end of the paper can be easily configured to contact the substantially central portion of the linear belt running surface of the belt conveying unit. Therefore, when configured in this way, the front end of the paper or the rear end of the paper can be brought into contact with the substantially central portion of the belt running surface to sufficiently bend the belt conveying means. Shock can be mitigated.
On the other hand, this also makes it possible to shorten the overall length of the belt conveying means. That is, the length from one pulley of the second conveying roller pair to the substantially central position on the belt is approximately the same as the length on the belt from the substantially central position to the other pulley. Since it is sufficient to ensure the length, as described in the fifth embodiment, both the lengths of the contact portion on the belt can be shortened by the amount close to the holding portion of the second conveying means. Thus, the belt length can be shortened. Further, in the configuration in which the belt length is shortened as described above, it is possible to appropriately eliminate a contact member for imparting an appropriate tension to the belt in order to prevent the belt from slackening. The configuration can be simplified.

  Next, a sixth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component and member same as said 5th Embodiment, and description is abbreviate | omitted or simplified. Although not particularly described, configurations not described in the present embodiment, that is, a sheet transport device, other configurations, and operations thereof are the same as those in the fifth embodiment.

  As shown in FIG. 15, the paper transport device 5 of the sixth embodiment maintains the posture of the paper constant regardless of the number of stacked paper sheets, and always keeps the uppermost paper constant. A pickup device configured to pull out and convey the uppermost sheet from a sheet storage unit serving as a sheet feeding unit configured to be supplied to a sheet feeding position fixedly set at a position, and a pickup roller 60 to the feed roller 61, at least, while maintaining the posture of the sheet in a stacked state, the sheet is configured to be conveyed substantially straight, and further between the feed roller 61 and the belt. Until the leading edge of the paper reaches the conveying surface of the belt, the posture of the paper is similarly maintained and the paper is conveyed substantially straight.

  The tray bottom plate on which the sheets are stacked is configured as a so-called paper feed table, and is provided so as to move up and down while maintaining an angle at which the sheets are stacked substantially horizontally. That is, the method of moving up and down the bottom plate as the paper feed table is often used in a large capacity tray (LCT), a manual feed tray, and the like. This is a rising method, and FIG.

More specifically, as shown in the figure, the tray bottom plate 97 is generally formed in a flat plate shape that secures a planar shape to the extent that the maximum size paper S that the copying machine 1 can handle can be placed. In addition, while the surface in contact with the sheet is always held on a horizontal plane by an appropriately configured restriction member, the change in the horizontal position is restricted and is movable in the vertical direction. For example, an appropriate portion on the tray bottom plate 97 is ruggedly fitted to a rail-shaped fixed guide member (not shown) formed of a ridge or groove extending in the vertical direction so as to be slidable in the member extending direction. Yes. Further, the tray bottom plate 97 is configured to drive the tray bottom plate 97 up and down to an arbitrary position within a range that can be moved in the vertical direction defined by the regulating member by an elevator mechanism (not shown) having an appropriate configuration. The mechanism uses a stepping motor or the like (not shown) as a drive source. Further, as a position detection sensor for detecting whether or not the topmost stacked paper is at the paper feed position, a position detection sensor (not shown) or the like is provided along with the paper feed position or the pickup roller 60. Based on the detection result, the ascending drive operation of the elevating mechanism is controlled in a predetermined manner by an appropriate control circuit or the like.
Therefore, in the configuration mainly including the tray bottom plate 97 as described above, based on the detection result of the position detection sensor, the stacking surface is held up on the horizontal plane and is driven to be raised by the lifting mechanism and loaded on the tray bottom plate 97. Similarly, the sheet is transported upward while the sheet surface is held on a horizontal plane, and the uppermost position is reached at the sheet feeding position defined as the position where the sheet contacts the pickup roller 60 that is rotationally driven at a predetermined fixed position. The paper is positioned.

In the paper transport device 5 according to the present embodiment, the paper travels substantially straight and reaches the first transport means 6 in the section until the leading edge of the paper reaches the first transport means 6. In the section until the leading edge of the paper reaches the belt conveying means 8, the paper advances substantially straight.
In other words, on the basis of the paper feed position and the paper surface at the paper feed position, the first transport means 6 so that the paper transport surface substantially coincides with a virtual plane extending the paper surface. Is disposed in a predetermined plane and a gripping roller 81 serving as a conveying member in the inner direction of the second conveying means 7 is in contact with the outer periphery of the virtual plane extending from the sheet conveying surface of the first conveying means 6, A belt conveying means 8 that is arranged to select a predetermined gap distance and that extends obliquely downward facing the grip roller 81 is arranged.
That is, as in the above-described embodiment, the first conveying unit 6 is a sheet feeding / separating mechanism that employs the FRR sheet feeding method, and is generally in the vertical direction so that the upper feed roller 61 and the lower reverse roller 62 are in contact with each other. The nip portion as a contact point between the rollers 61 and 62 is positioned on a virtual plane indicated by a broken line in the figure, and passes through the nip portion and is orthogonal to the virtual plane. The rollers 61 and 62 are arranged so that the rotation centers of the rollers 61 and 62 are located on the line.
The second conveying means 7 has a grip roller 81 as one opposing pair arranged in the inner direction and a belt conveying means 8 as the other opposing pair arranged in the outer direction. The conveying means 8 includes a pulley 83 having a predetermined position on a horizontal line with respect to the rotation center of the grip roller 81 as a rotation center. The pulley 83 is lower than the sheet conveying surface by a predetermined distance and is first than the pulley 83. A pulley 84 is arranged with the position close to the conveying means as a center of rotation, and the conveyor belt 82 is wound around these pulleys 83, 84, and the inner periphery of the belt is supported by the pulley 83. The outer periphery of the conveyor belt 82 is in contact with the outer periphery of the grip roller 81 while securing a predetermined pressure, and this contact portion is a nipping portion (nip portion).
In the two sections, a transport guide member 99 is provided as a guide member provided in the outer direction of the paper transport path, and the guide surface 99A formed by the transport guide member 99 It is formed in a flat shape that is provided continuously in common in one section, and is provided substantially parallel to a virtual plane that is also a sheet transport surface by the first transport means 6 alone.

  In the present embodiment, the sheet stacking surface of the uppermost sheet positioned at the sheet feeding position is formed by using a sheet storage unit mainly composed of a tray bottom plate on which the stacked sheets can be placed and moved up and down to an arbitrary position. The nip portion of the first transport unit is positioned on a virtual plane extending the paper surface as a reference, and the virtual transport plane extends in the paper transport direction of the first transport unit alone. The first conveying means is configured as described above so as to align with the above-mentioned direction, and the belt conveying surface of the belt conveying means of the first conveying means is arranged so as to intersect with the extending direction. Then, a paper transport path in the section from the pickup roller to the feed roller as the first transport means is formed so as to be substantially parallel to the virtual plane with a predetermined gap distance, and the transport is performed. The guide surface of the guide member positioned in the outer direction of the conveying path by forming the guide surface of the guide member positioned in the outer direction of the road and the sheet conveying path of the section from the feed roller as the first conveying means to the belt conveying means A surface is formed. Further, a single conveyance guide member 99 takes charge of these two guide surfaces, and this conveyance guide member 99 forms one continuous planar guide surface 99A in which the substantially parallel relationship is set. doing.

The guide surface 99 </ b> A of the transport guide member 99 is provided so that the peripheral edge that is the downstream end in the transport direction is close to the belt travel surface of the transport belt 82 without being in contact therewith. That is, the peripheral edge, which is the downstream end of the guide surface 99A, is substantially linear in a direction perpendicular to the conveying direction while ensuring a predetermined small gap distance from the belt traveling surface so as not to generate the above-mentioned sneak noise. Is formed. Further, the transport guide member 99 has a vertical surface facing the front end surface in the paper transport direction of the sheets S stacked on the tray bottom plate 97, and the front end surfaces of all the stacked sheets S on this vertical surface. These sheets S are stacked on the tray bottom plate 97 in an overlapping manner accurately and orderly. Further, other end portions other than the leading end of the sheet S are brought into contact with other members having an appropriate configuration (not shown), and similarly, the position of the sheet S in the horizontal direction on the tray bottom plate 97 is restricted to a predetermined value. .
Further, in this embodiment, at least the lower stage of the paper storage means mainly including the tray bottom plate 97 driven up and down is not provided with other paper storage means, and at least the paper storage means having the tray bottom plate 97. The above-mentioned second conveyance path configured to pass through the paper storage means from below is not provided.

As described above, according to the paper transport device of the sixth embodiment, at least the same effects as the paper transport device of the fourth embodiment described above can be obtained. In addition to this, in the paper storage means used in the first to fifth embodiments described above, the angle of the bottom plate changes depending on the number of sheets stacked, that is, the inclination angle of the paper stacking surface can be conveyed. In contrast to the variation within the allowable range, in this embodiment, the angle of the bottom plate can be made constant regardless of the number of sheets. In other words, the sheet surface of the uppermost sheet as the sheet stacking surface at the start of conveyance is used. It can always be kept at a constant angle and a fixed position such as horizontal. In addition, a section from the position where the uppermost sheet is stacked until the leading end of the sheet reaches the first transport unit, and a section from the position where the leading end of the sheet reaches the belt transport unit. In both sections, since it is configured to advance straight in the transport direction and reach the belt transport means without changing the orientation of the paper surface, the transport resistance can be further reduced, It can be transported more stably, and it is not necessary to produce the above-mentioned splash sound.
That is, in the first to fifth embodiments, when the number of sheets placed on the bottom plate is large, the inclination angle of the bottom plate is small, the bottom plate is inclined gently, and the paper is conveyed and the paper feed advances. Accordingly, when the number of sheets remaining on the bottom plate decreases, the inclination angle of the bottom plate increases and the bottom plate inclines more steeply, and accordingly, the inclination posture of the paper surface of the uppermost sheet changes.
On the other hand, according to the sixth embodiment, the sheet in progress on the transport path from the portion in contact with the pickup roller to the first transport means is guided by the guide member in the transport path outer direction. There is no need to change or deform the direction of the paper in the direction of the thickness of the paper, and the resistance received by the paper in progress along the transport path from the guide member is only the minimum necessary. In addition, the resistance that the second half of the paper in progress of the movement receives from the paper remaining on the tray bottom plate can be kept to a minimum. That is, regardless of the decrease in the number of sheets placed on the tray bottom plate, the posture of the uppermost sheet is always maintained in the same posture, and the uppermost sheet extends the sheet surface. With the direction set as the traveling direction, the paper is conveyed at least until the leading edge of the paper reaches the belt conveyance surface while maintaining the posture. For this reason, when the pickup roller is in contact with any part of the paper, the first half and the second half of the paper with the pickup roller as the boundary in the conveyance direction are completely deformed in the thickness direction of the paper. Instead, the sheet surface of the uppermost sheet in the stacked state can be held in an extended virtual plane. By these, it is possible to minimize the resistance that the sheet receives during the sheet conveyance process up to the first conveyance unit. On the other hand, it is not necessary to cause a step that causes abnormal noise in the guide member in the outer direction of the sheet conveying path between the pickup roller and the belt conveying unit.

  In the first to fifth embodiments, the number of sheets that can be stacked and stored in the paper tray is limited by the height dimension of the paper tray corresponding to the thickness direction of the paper. In the paper transport device of the embodiment, since the number of sheets is defined by the movable range of the bottom plate that can move in the vertical direction, the movable range of the bottom plate can be secured sufficiently larger than the height dimension of the paper tray. A large number of sheets can be stacked on the bottom plate and fed. For this reason, according to the image forming apparatus adopting the large-volume sheet feeding tray and the sheet conveying apparatus of the sixth embodiment, the number of sheets to be replenished can be reduced and a large number of sheets can be stably supplied at one time. It is possible to form an image through which paper is continuously passed, and the convenience as an image forming apparatus and the image forming performance can be improved.

  As described above, in the belt conveyance unit 8 of the paper conveyance device 5 shown in each embodiment and the like, one of the opposed pairs of the second conveyance unit 7 (nipping conveyance unit) is in contact with the leading edge of the sheet (sheet). It can be said that this is an example of a movement guide means for moving and guiding the sheet S toward the nip portion (clamping portion) with the grip roller 81 while maintaining the contacted state. Therefore, the movement guide means is not limited to the belt conveying means 8 and may be anything as long as it has the above-described configuration and function and exhibits the above-described effects.

In each of the above-described embodiments, 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, it is only necessary to support and transport the lower surface of the transport target. If necessary, it is not necessary to use a holding and conveying means in which a holding portion is formed by a counter member.
Further, in each of the above-described embodiments, 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 direction) has been described, but the present invention is not limited to this. , It may be changed from a substantially horizontal direction to a downward direction (substantially vertical direction), a downward direction in the vertical direction, an upward direction to a substantially horizontal direction, or both may be oblique directions. .

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.
Furthermore, as a configuration in which the guide surfaces formed by several guide members in the outer and inner contour directions in the above-described embodiments are positioned in the above-described several intervals where no roller member or roller member is arranged. 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.

  Further, although the movement guide means has been described as having an action of adding the driving force of the paper, it can be said that it is due to the reduction of the conveyance load when viewed as the entire apparatus. In that case, for example, as a means for reducing the conveyance load due to the contact of the sheet with the inner surface of the guide surface, the inner surface of the guide surface or the outer surface of the paper without applying a driving force to the paper by the movement guide unit. The contact portion may be subjected to a low-friction process that does not cause a jam in the paper, or a low-friction member may be attached to form a low-friction member (fixing of the curved guide member 103 and the curved guide member 104 shown in FIG. 23). (See the shaded area on the guide surface 103A). Furthermore, you may combine a movement guide means and the guide which has the said low friction part.

  Further, in each of the above-described embodiments, the FRR paper feed method is adopted as the paper feed separation mechanism. However, the present invention is not limited to this. As long as the separation mechanism keeps moving in the conveyance direction, an appropriate friction separation method may be adopted. For example, a separation claw is used instead of the reverse roller or a fixed member for the above-described feed roller. A friction pad system having a configuration in which the friction pad is press-contacted 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 paper 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 transport direction is prevented. On the other hand, the upper sheet is set so that the conveying 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 the paper continues to advance in the transport direction.

The present invention relates to an image forming apparatus relating 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 batch-transfers to a sheet. Needless to say, the endless belt-like photoconductor 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. You may apply also to a formation 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 can also be applied to an image forming apparatus in which the conveyance path until the sheet is discharged to the sheet discharge tray is not substantially vertical (substantially vertical).
In a printing machine including a stencil printing machine or the like, the present invention relates to sheet conveyance that conveys and supplies a sheet (paper) from a sheet storage means (paper feed tray) or a sheet stacking means (bottom plate or paper feed table) to a printing unit main body. You may apply also to an apparatus.

  The above-described copying machine as an image forming apparatus is configured to manually set a document to be read, but is equipped with an ADF (automatic document feeder) for automatically reading a plurality of documents (sheets). The sheet conveying apparatus of the present invention may be applied to the ADF in a copying machine, a printing apparatus, or the like. That is, not only automatically transporting a single document to the reading position, but also automatically transporting the uppermost or lowermost document one by one to the reading position among appropriate plural and stacked documents, The present invention may be applied to an ADF having a configuration in which a read image is obtained from a document and then stacked and accommodated at a predetermined conveyance location.

Further, the image forming apparatus is not limited to a copying machine, but includes a printing machine including a facsimile, a printer, an ink jet recording apparatus, a stencil printing apparatus, etc., and an image mainly having an image reading function having a scanner for reading an image from a document. The present invention may be applied to a reading device or the like or a multi-function device in which at least two of them are combined.
Further, as described above, the sheet conveying device applied to the image forming apparatus can be used only for conveying a sheet (sheet) as described above, or can be used only for conveying a document instead of a sheet, For example, two paper conveying devices may be provided separately for conveyance. Further, the present invention may be applied to an image reading apparatus having a scanner for reading an image from original paper and mainly having an image reading function, and similarly used for conveying an original instead of paper.
In any case, the object to be conveyed is not limited to either the image formation target paper or the image reading target original, and sheet materials having a wide variety of configurations are targeted for conveyance. In an apparatus or apparatus that needs to change the sheet conveyance direction while saving space on the sheet conveyance path, an optimum sheet conveyance apparatus can be obtained.

  As described above, the present invention has been described with respect to specific embodiments, modifications, and examples. However, the technical scope disclosed by the present invention is exemplified by the above-described embodiments, modifications, and examples. The present invention is not limited to those described above, and may be configured by appropriately combining them, and various embodiments, modifications, or examples may be configured within the scope of the present invention according to the necessity and application. It will be apparent to those skilled in the art to obtain.

1 Copying machine (image forming device)
2 Image forming apparatus body 3 Paper feed device (paper feed unit)
4 Document reading device (document reading unit)
5 Paper transport device (sheet transport device)
6 First conveying means (first conveying means)
7 Second transport means (second transport means)
8 Belt conveying means (movement guide means)
9 Eject tray (configures sheet ejection section)
10 Photosensitive unit (image forming unit)
10A photoconductor (image carrier)
11 Fixing device 12 Developing device 13 Transfer device 20 Toner container 21 Registration roller pair 50, 97 Bottom plate (sheet stacking means)
51A Guide surface of the paper feed tray (first guide member)
51 Paper feed tray (sheet storage means)
60 Pickup roller (feed rotating member)
61 Feed roller (constitutes one of the opposed pair of the first conveying means, the sheet feeding rotating member, and the sheet separating mechanism)
62 Reverse roller (the other of the opposing pair of the first conveying means, the separating member, the sheet separating mechanism, and a rotating member provided on the outer shell)
65 idler gear (for transmitting the driving force to the feed roller of the first conveying means)
67 Manual feed tray 70 Conveying guide member ( inner guide member )
71 Conveying guide member ( outer guide member )
72, 92 Conveying guide member (outside of longitudinal conveying path)
73 Conveying guide member (for forming the inlet from the paper feed tray to the conveying path)
95, 99 conveying guide member (guide member arranged on the outer side forming the sheet conveying path in the section from the paper feeding position to the position reaching the belt conveying means)
80 Housing (sheet transport device main unit)
81 Grip roller ( rotary conveyance drive means, the other of the opposing pair of second conveyance means)
82 Conveyor belt ( belt )
83 pulley (first belt holding rotating member, structure member of the belt conveying means as one of the opposing pair of second conveying means)
84 pulley (second belt holding and rotating member, structure member of the belt conveying means as one of the opposing pair of second conveying means)
85 Tension roller (contact member)
90 Transport guide member ( inner guide member )
91 Paper guide member ( outer guide member )
93 Paper guide member ( outer guide member )
A First transport path (first sheet transport path)
B Second transport path (second sheet transport path)
R1 transport path R2 manual feed path R3 reverse transport path S paper (sheet / sheet-like recording medium, image forming medium)
α Tangent line between the feed roller and the grip roller as opposed pairs arranged in the inner direction in each of the first conveying means and the second conveying means β orthogonal to the line connecting the rotation centers of the feed roller and the reverse roller And a line passing through the contact points of the two (lines included in the plane defined by the contact points of the feed roller and the reverse roller as the separating member)
θ Entry angle

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)

Claims (11)

First conveying means for conveying the sheet in the first sheet conveying direction ;
Disposed downstream of the first sheet conveying direction of the first conveying means, second to convey the sheet conveyed by the first conveying unit in a second sheet conveying direction different from the first sheet conveying direction The second conveying means is a rotary conveying drive that is disposed in the inner direction of the sheet conveying path formed between the first conveying means and the second conveying means and is rotationally driven. And belt conveying means that is arranged in the outer direction of the sheet conveying path and conveys the sheet by being driven and rotated in contact with the rotary conveying driving means,
Arranged in the inner direction of the sheet conveying path formed between the first conveying means and the second conveying means to form a sheet conveying path from the first conveying means to the second conveying means An inner guide member having a curved portion;
An outer shell that is arranged in the outer direction of the sheet conveying path formed between the first conveying means and the second conveying means and forms a sheet conveying path from the first conveying means to the belt conveying means. A sheet conveying device comprising a guide member,
The belt conveying means wraps the belt, a first belt holding and rotating member disposed on the most downstream side in the second sheet conveying direction so as to hang around the belt and hold the belt so as to run. And a second belt holding and rotating member disposed on the most upstream side in the second sheet conveying direction so as to be held so as to be able to travel, and the leading end of the sheet has the second belt holding and rotating member and the second belt holding and rotating member. The belt holding rotating member is arranged so as to be in contact with the belt conveying surface excluding the belt portion held by the belt holding rotating member,
The axial center of the second belt holding and rotating member is above the lower end of the rotating member provided on the outer periphery of the first conveying means, and is the downstream end portion of the outer guide member in the first sheet conveying direction. It is arranged to be located below,
The rotation conveyance driving means that contacts the first belt holding rotation member via the belt is disposed so as to overlap the curved portion of the inner guide member in a cross section in which the rotation conveyance driving means rotates. sheet conveying apparatus characterized by there. 2. The sheet conveying apparatus according to claim 1 , wherein the belt conveying unit is arranged such that a leading end portion of the sheet enters with an acute angle of incidence with respect to the conveying surface of the belt . 3. The sheet conveying apparatus according to claim 1 , wherein the width of the belt in the sheet width direction orthogonal to the first sheet conveying direction of the first conveying means is substantially the same as the width of the conveyed sheet. . A contact member that contacts the belt;
4. The sheet conveyance according to claim 1, wherein the contact member is disposed at a position different from a position where a rear end of the conveyed sheet is in contact with a conveyance surface of the belt. apparatus. The sheet conveying apparatus according to any one of claims 1 to 4, wherein an outer diameter of the first belt holding and rotating member is larger than that of the second belt holding and rotating member . The first conveying unit includes a sheet feeding rotating member and a separating member in contact with the sheet feeding rotating member so as to separate the sheet into one sheet and convey the sheet toward the second conveying unit. Sheet separation mechanism,
Including at least one outer guide member that forms a sheet conveying path from the sheet separating mechanism to the belt conveying unit;
6. The plane defined by the contact points of the sheet feeding rotation member and the separating member and the guide surface of the outer guide member are set in a substantially parallel relationship . The sheet conveying apparatus according to any one of the above. The first transport unit is a transport unit that forms a sandwiching unit that sandwiches and transports the sheet,
At least a part of the inner guide member is provided outside a line segment connecting the center of the sandwiching part of the first transport unit and the center of the sandwiching part of the second transport unit and the belt transport unit. sheet conveying apparatus according to any one of claims 1 to 6, characterized in that it is. 8. A sheet having a metric basis weight of 80 to 300 g / m < ² > can be conveyed from the first conveying means to a clamping part between the second conveying means and the belt conveying means . The sheet conveying apparatus according to any one of the above. The sum of the sheet conveyance force by the first conveyance unit and the sheet conveyance force by the belt conveyance unit is larger than the total sheet conveyance load of the inner guide member and the outer guide member. Item 9. The sheet conveying apparatus according to any one of Items 1 to 8. An image reading apparatus comprising the sheet conveying apparatus according to claim 1 . An image forming apparatus, comprising an image reading apparatus of a sheet conveying apparatus and / or claim 10, wherein according to any one of claims 1 to 9.

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