JP2011088685A - Sheet material conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the degree of dents of a sheet material due to a projection part for kicking out the upstream end of the sheet material when conveying the sheet material by clipping it. <P>SOLUTION: This sheet material conveying device conveys sheet materials by clipping a sheet material with a delivery roller 12 and a delivery roll 13 facing the delivery roller 12. The delivery roll 13 includes: a projection part 13d projecting outside from the peripheral surface of the delivery roll 13 to kick out the upstream end of the sheet material in the conveying direction from a clip part clipping the sheet material; and a ring part 13c rotating with the delivery roll 13. While clipping the sheet material with the clip part, the ring part 13c is pushed by the sheet material and elastically deformed in the circumferential direction of the delivery roll 13, and the projection part 13d retreats inside from the peripheral surface of the delivery roll 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet material conveying apparatus for nipping and conveying a sheet, and more particularly to a sheet material conveying apparatus for nipping and conveying a sheet material on which an image is formed and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer, a configuration is known in which a sheet material on which an image is formed is nipped and conveyed by a pair of conveying rollers and discharged toward a discharge tray. Furthermore, in order not to leave the rear end (upstream end in the transport direction) of the sheet material in the vicinity of the transport roller pair when discharged to the discharge tray, a protrusion is provided on the outer peripheral portion of one of the transport roller pairs, A configuration in which the rear end of the sheet material is kicked out by the protrusion is known.

  However, when the sheet material on which an image is formed is sandwiched and conveyed by the pair of conveying rollers, if the protrusion comes into contact with the sheet material with a high pressure, the surface of the sheet material is pressed by the protrusion and a dent mark is formed. I'll follow you.

  In order to solve this problem, there has been proposed one in which one of the conveying rollers provided with the protrusions is made hollow (see Patent Document 1). In Patent Document 1, the one transport roller projects in a circumferentially divided manner into a hollow annular portion that is cantilevered as a part of the outer peripheral surface and an outer peripheral surface on the opening side of the annular portion. The structure provided with the protrusion part which does is disclosed. Further, a configuration is disclosed in which a slit is provided in the annular portion in the axial direction in order to weaken the bending rigidity of the annular portion.

JP-A-11-133686

  As described above, in Patent Document 1, the bending rigidity of the annular portion is weakened by the slit provided in the annular portion. Therefore, when the sheet material sandwiched between the roller pairs pushes the protrusion, the annular portion is bent in the axial direction (direction in which the slit is provided), and the protrusion is retracted inward from the outer peripheral surface of the roller by the bending. The

  That is, in Patent Document 1, when the sheet material pushes the protrusion, the annular portion is bent in the axial direction intersecting the rotation direction of the roller by the slit provided in the axial direction. However, there is still a possibility that a dent mark due to the protruding portion may be attached to the sheet material nipped and conveyed by the conveying roller pair.

  The object of the present invention is a further development of the conventional technique described above, and when the sheet material is nipped and conveyed, the dent marks caused by the protrusions for kicking out the rear end of the sheet material are further reduced. It is an object of the present invention to provide a sheet material conveying apparatus that can be used.

  In order to solve the above-described problems, the present invention provides a sheet material conveying apparatus that nipping and conveying a sheet material by a first rotating body and a second rotating body facing the first rotating body, The rotating body of 2 has a protrusion protruding outward from the outer peripheral surface of the second rotating body for kicking out the upstream end in the conveying direction of the sheet material from the clamping portion that clamps the sheet material, An elastic portion that rotates together with the second rotating body is provided, and the elastic portion is elastically deformed in the circumferential direction of the second rotating body by being pushed by the sheet material in a state where the sheet material is held by the holding portion. The protrusion is retracted inward from the outer peripheral surface of the second rotating body.

  According to the present invention, when pressed by the sandwiched sheet material, the elastic portion is elastically deformed in the circumferential direction of the second rotating body, and the protruding portion is on the inner side of the outer peripheral surface of the second rotating body. evacuate. As a result, the pressure at which the protrusions abut on the sheet material is further reduced, and the dent marks on the sheet material can be further reduced or eliminated.

(A) and (b) are sectional side views of the sheet material conveying apparatus according to the first embodiment, and (c) is a front view of the sheet material conveying apparatus according to the first embodiment. (A) and (b) are sectional side views of the sheet material conveying apparatus according to the second embodiment, and (c) is a front view of the sheet material conveying apparatus according to the second embodiment. Cross section of image forming apparatus

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

  First, a schematic configuration of the image forming apparatus will be described with reference to FIG. 3, and then an embodiment of the sheet material conveying apparatus that sandwiches and conveys the sheet material with the image forming apparatus will be illustrated with reference to FIGS. 1 and 2. To explain.

  FIG. 3 is a schematic cross-sectional view illustrating a configuration of a laser beam printer which is an example of an image forming apparatus. In the laser beam printer shown in FIG. 3, the feeding tray 6 on which the sheet material P is placed is arranged at the lower part of the apparatus, and the discharge tray 14 on which the printed sheet material is stacked is arranged at the upper part of the apparatus. Further, a process cartridge 7 including a photosensitive drum 8 and the like constituting an image forming unit is disposed between the feeding tray 6 and the discharge tray 14.

  The registration sensor 4 detects the position of the front end (downstream end in the transport direction) of the sheet material. Based on this detection signal, in order to draw an image from a predetermined position of the sheet material P, the leading end position of the sheet material P and the light emission timing of the laser scanner 5 as the exposure light source are synchronized.

  Then, the sheet material P fed from the feeding tray 6 by the feeding roller 2 is conveyed to the transfer unit by the conveying rollers 3a and 3b, and the photosensitive drum 8 by the transfer roller 9 which constitutes the image forming unit together with the photosensitive drum 8. The upper toner image is transferred. The sheet material P on which the toner image is formed is heated and pressed by a fixing unit F constituted by the heating member 10 and the pressure roller 11, and the toner image is fixed on the sheet material P. Thereafter, the sheet material P on which the toner image is fixed is discharged out of the apparatus by the discharge roller pairs 12 and 13 and is stacked on the discharge tray 14.

[First Embodiment]
Here, a sheet material conveying apparatus that sandwiches and conveys a sheet material will be described with reference to FIG. FIG. 1A is a side sectional view of the sheet material conveying apparatus according to the first embodiment (sheet material rear end kicked-out state), and FIG. 1B is a side sectional view of the sheet material conveying apparatus according to the first embodiment. (Sheet material conveyance state), FIG.1 (c) is a front view of the sheet material conveyance apparatus which concerns on 1st Embodiment.

  Here, a sheet material conveying apparatus that sandwiches and conveys the sheet material P by the discharge roller 12 as the first rotating body and the discharge roller 13 as the second rotating body facing the discharging roller 12 is illustrated. explain.

  As shown in FIG. 1, the discharge roller 12 is configured by press-fitting a roller portion (high friction member such as rubber) 12a into a discharge roller shaft 12b, and is driven by driving from a drive source. The discharge roller 13 is pressed with a predetermined pressure against the discharge roller 12 by a pressure spring 15, and rotates following the discharge roller 12. Specifically, the discharge roller 13 has a roller portion (body portion) 13a for holding and conveying the sheet material P together with the roller portion 12a of the discharge roller 12, and a holding portion (nip portion) for holding the sheet material. Is forming. The roller part 13a of the discharge roller 13 is made of a resin material such as fluororesin or polyacetal so that the toner heated by the fixing part F is less likely to adhere to the recording surface of the sheet material P fixed by the fixing part F. Has been. Further, the discharge roller 13 is provided with a ring portion 13c, which is an elastic portion, on a roller shaft 13b provided at the rotation center of the roller portion 13a, and rotates together with the discharge roller 13. The ring portion 13c is provided with a projection 13d on the outer peripheral portion thereof, so that the rear end (upstream end in the conveying direction) of the sheet material P is not left in the vicinity of the discharge roller pairs 12 and 13 when discharged to the discharge tray 14. A function of kicking the rear end of the material P is provided.

  Here, the ring portion 13c having the protruding portion 13d will be described in detail. As shown in FIG. 1 (a), the ring portion 13c of the discharge roller 13 is located outside the outer peripheral surface of the discharge roller 13 for kicking out the upstream end of the sheet material in the conveyance direction, as described above. It has a protruding portion 13d that protrudes. The ring portion 13c is pushed by the sheet material sandwiched by the sandwiching portion and elastically deforms in the circumferential direction of the discharge roller 13, and the projection 13d is retracted inward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). To do. Specifically, the ring portion 13 c is an elastic portion provided in a spiral shape from the rotation center side of the discharge roller 13 toward the outside. One end 13c1 on the rotation center side of the ring portion 13c is supported by the roller shaft 13b of the discharge roller 13. Further, the other outer end portion 13c2 forms the protruding portion 13d protruding outward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). That is, the protrusion 13d that protrudes outward from the outer peripheral surface of the discharge roller 13 included in the ring portion 13c is formed integrally with the ring portion 13c.

  Therefore, in a state where the sheet material P that has passed through the fixing portion F is nipped by the discharge roller pair including the discharge roller 12 and the discharge roller 13, the spiral ring portion 13c has a sheet as shown in FIG. It is pushed by the material P and elastically deforms in the circumferential direction of the discharge roller 13. At this time, the protruding portion 13d formed at the tip of the ring portion 13c, which is an elastic portion, is pushed by the sheet material P and retracts from the conveyance path of the sheet material P. That is, the protrusion 13d is retracted inward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). Further, after the rear end of the sheet material P passes through the nip between the discharge roller 12 and the discharge roller 13, the spiral ring portion 13c is restored to the original position as shown in FIG. 13d protrudes in the conveyance path of the sheet material P. That is, the protruding portion 13d protrudes outward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). Therefore, even when the rear end of the sheet material P remains in the vicinity of the nip portion between the discharge roller 12 and the discharge roller 13, the protruding portion 13 d kicks out the rear end of the sheet material P toward the discharge tray 14. It becomes possible to discharge.

  As described above, according to the present embodiment, when pressed by the sheet material sandwiched between the discharge roller 12 and the discharge roller 13, the ring portion 13c is elastically deformed in the circumferential direction of the discharge roller 13, and the protrusion The portion 13d is retracted inward from the outer peripheral surface of the discharge roller 13. As a result, the pressure with which the protrusion 13d abuts against the sheet material P is reduced, and the dent marks on the sheet material P can be further reduced or eliminated.

  Further, the discharge roller 13 including the roller portion 13a, the roller shaft 13b, and the ring portion 13c can be integrally formed by injection molding using a resin material such as fluororesin or polyacetal, and is manufactured at a lower cost. Is possible.

  Further, the ring portion 13c provided as a part of the discharge roller 13 can be finely set in material, wire diameter, winding diameter, number of windings, and the like. Therefore, it is possible to finely set the pressure for retracting the ring portion 13c including the protruding portion 13d in accordance with the printing speed of the image forming apparatus, the type of the sheet material, and the like.

[Second Embodiment]
Next, the sheet material conveying apparatus according to the second embodiment will be described with reference to FIG. 2A is a side sectional view of the sheet material conveying apparatus according to the second embodiment (sheet material rear end kicked-out state), and FIG. 2B is a side sectional view of the sheet material conveying apparatus according to the first embodiment. (Sheet material conveyance state), FIG.2 (c) is a front view of the sheet material conveyance apparatus which concerns on 1st Embodiment.

  Also here, a sheet material conveying apparatus that sandwiches and conveys the sheet material P by the discharge roller 12 as the first rotating body and the discharging roller 13 as the second rotating body facing the discharging roller 12 is exemplified. explain.

  As shown in FIG. 2, the discharge roller 12 has the same configuration as that described above. The discharge roller 13 is pressed with a predetermined pressure against the discharge roller 12 by a pressure spring 15, and rotates following the discharge roller 12. Specifically, the discharge roller 13 has a roller portion (body portion) 13a for holding and conveying the sheet material P together with the roller portion 12a of the discharge roller 12, and a holding portion (nip portion) for holding the sheet material. Is forming. The roller part 13a of the discharge roller 13 is made of a resin material such as fluororesin or polyacetal so that the toner heated by the fixing part F is less likely to adhere to the recording surface of the sheet material P fixed by the fixing part F. Has been. Further, the discharge roller 13 is press-fitted with metal springs 13e, which are elastic portions described later, at both ends of the roller portion 13a in the axial direction, and rotates together with the discharge roller 13. The metal spring 13e is provided with a protruding piece 13f as a protruding portion on the outer peripheral portion, and when the sheet spring P is discharged to the discharge tray 14, the rear end (upstream end in the transport direction) of the sheet material P is placed near the discharge roller pair 12, 13. In order not to remain, it has a function of kicking out the rear end of the sheet material P.

  Here, the metal spring 13e having the kick-out piece 13f will be described in detail. As shown in FIG. 2A, the metal spring 13 e provided on the discharge roller 13 is an elastic portion (metal winding spring) provided in a spiral shape in the axial direction of the discharge roller 13. The metal spring 13e is supported by the roller portion 13a of the discharge roller 13 at one end portion 13e1 side. The kick-out piece 13f protruding outward from the outer peripheral surface of the discharge roller 13 (roller portion 13a) is press-fitted into the other end portion 13e2. That is, the kick-out piece 13f protruding outward from the outer peripheral surface of the discharge roller 13 of the metal spring 13e is formed of an elastic material different from the metal spring 13e, and the other end of the metal spring 13e. It is attached to the part 13e2.

  Therefore, in a state where the sheet material P that has passed through the fixing portion F is nipped by the discharge roller pair including the discharge roller 12 and the discharge roller 13, the spiral metal spring 13e is formed as shown in FIG. It is pushed by the material P and elastically deforms in the circumferential direction of the discharge roller 13. At this time, the kick-out piece 13f press-fitted into the tip of the metal spring 13e, which is an elastic portion, is pushed by the sheet material P and retreats from the conveyance path of the sheet material P. That is, the kick-out piece 13f is retracted inward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). Further, after the rear end of the sheet material P passes through the nip between the discharge roller 12 and the discharge roller 13, the spiral metal spring 13e is restored to the original position as shown in FIG. The piece 13f protrudes in the conveyance path of the sheet material P. That is, the kick-out piece 13f projects outward from the outer peripheral surface of the discharge roller 13 (roller portion 13a). Therefore, even when the rear end of the sheet material P remains in the vicinity of the nip portion between the discharge roller 12 and the discharge roller 13, the kick-out piece 13 f kicks out the rear end of the sheet material P toward the discharge tray 14. Can be discharged.

  As described above, also in this embodiment, when pressed by the sheet material sandwiched between the discharge roller 12 and the discharge roller 13, the metal spring 13e is elastically deformed in the circumferential direction of the discharge roller 13 and kicks out. The piece 13f is retracted inward from the outer peripheral surface of the discharge roller 13. Thereby, the pressure with which the kicking piece 13f abuts on the sheet material P is reduced, and the dent marks on the sheet material P can be further reduced or eliminated.

  Further, the metal spring 13e provided as a part of the discharge roller 13 can be finely set in material, wire diameter, winding diameter, winding number, and the like. For this reason, it is possible to finely set the retraction pressure of the metal spring 13e including the kick-out piece 13f in accordance with the printing speed of the image forming apparatus, the type of the sheet material, and the like.

  In particular, according to the present embodiment, the length of the metal spring as the elastic portion in the circumferential direction can be made longer than that in the above-described embodiment, so that the kick-out piece 13f is retracted with a smaller pressure. The pressure can be set finely. If the retracting pressure of the kick-out piece 13f can be set small, even a thinner sheet material or a sheet material that easily absorbs moisture and has a dent mark can be prevented from forming a dent mark.

[Other Embodiments]
In the first embodiment described above, the configuration in which the protrusion (projection 13d) is integrally provided at the end of the elastic portion (ring portion 13c) is exemplified. However, the protrusion is provided separately from the elastic portion, and the elastic portion. You may make it attach to the edge part. Moreover, in 1st Embodiment, although the ring part 13c as an elastic part was illustrated integrally with the roller part and the roller axis | shaft with the resin material, the structure was illustrated, but it is not limited to this. For example, as in the second embodiment, the ring portion 13c as the elastic portion may be a metal wound spring.

  In the second embodiment described above, the protrusion (the kicking piece 13f) is provided separately from the elastic portion (metal spring 13e) and is attached to the end of the elastic portion. And may be formed integrally. Moreover, in 2nd Embodiment, although the structure which used the elastic part as the metal spring was illustrated, it is not limited to this. For example, as in the first embodiment, the elastic portion may be a wound spring made of a resin material.

  In the above-described embodiment, the spiral elastic portion (ring portion 13c) is directed outward from the rotation center of the rotating body, and the spiral elastic portion (metal spring 13e) is illustrated in the axial direction of the rotating body. The spiral shape is not limited to this. As long as the elastic member is elastically deformed in the circumferential direction of the rotating body by being pushed by the sheet material held between the holding portions, the elastic portion may have a spiral shape other than those exemplified in the above-described embodiment.

  Further, in the above-described embodiment, the pair of rotating rollers that convey and hold the sheet material is exemplified as the pair of discharging rollers including the discharging roller and the discharging roller, but if the pair of rotating members that sandwich and convey the sheet material is used. For example, other roller pairs may be used. The rotating body is not limited to a roller or a roller, but may be an endless belt that rotates and moves.

  Further, in the above-described embodiment, the sheet material conveyance device integrally included in the image forming apparatus is exemplified, but the present invention is not limited to this. For example, the present invention is effective even if it is a sheet material conveying device that is detachable from the image forming apparatus, as long as the sheet material conveying device has a pair of rotating bodies that sandwich and convey the sheet material.

  Further, in the above-described embodiment, the sheet material conveying apparatus that nips and conveys a sheet material such as recording paper as a recording target is exemplified, but the present invention is not limited to this. For example, the same effect can be obtained even if the present invention is applied to a sheet material conveying apparatus that nipping and conveying a sheet material such as a document to be read.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus. However, the present invention is not limited to this, and other image forming apparatuses such as a copying machine and a facsimile machine, or a combination of these functions. Another image forming apparatus such as a multifunction peripheral may be used. The same effect can be obtained by applying the present invention to a sheet material conveying apparatus used in these image forming apparatuses.

P: Sheet material 12: Discharge roller (first rotating body)
13 ... discharge roller (second rotating body)
13c Ring part (elastic part)
13d ... Projection 13e ... Metal spring (elastic part)
13f ... kicking piece (protrusion)

Claims (7)

A sheet material conveying apparatus for nipping and conveying a sheet material by a first rotating body and a second rotating body facing the first rotating body,
The second rotating body has a protrusion protruding outward from the outer peripheral surface of the second rotating body for kicking out the upstream end in the conveying direction of the sheet material from the holding portion for holding the sheet material. An elastic part that rotates together with the second rotating body,
The elastic portion is pressed by the sheet material and elastically deformed in the circumferential direction of the second rotating body in a state where the sheet material is clamped by the clamping portion, and the protrusion portion of the second rotating body is A sheet material conveying device, wherein the sheet material is retracted inward from the outer peripheral surface.   The elastic portion is provided in a spiral shape from the rotation center side to the outside of the second rotating body, one end portion on the rotation center side is supported by the second rotating body, and the other outer side The sheet material conveying device according to claim 1, wherein an end portion of the sheet material is a protruding portion protruding outward from an outer peripheral surface of the second rotating body.   The elastic portion is provided in a spiral shape in the axial direction of the second rotating body, one end is supported by the second rotating body, and the other end is an outer peripheral surface of the second rotating body. The sheet material conveying device according to claim 1, wherein the sheet material conveying device is a protrusion protruding outward.   The protrusion part which protruded toward the outer side from the outer peripheral surface of the said 2nd rotary body which the said elastic part has is formed integrally with the said elastic part, Either of Claim 1 thru | or 3 characterized by the above-mentioned. The sheet material conveying apparatus according to claim 1.   The protruding portion of the elastic portion that protrudes outward from the outer peripheral surface of the second rotating body is formed of an elastic material different from the elastic portion, and is attached to the other end of the elastic portion. The sheet material conveying device according to any one of claims 1 to 3, wherein the sheet material conveying device is provided.   The sheet material conveying apparatus according to claim 1, wherein the elastic portion is a metal spring.   An image forming unit that forms an image on a sheet material, and the sheet material conveyance device according to any one of claims 1 to 6, which conveys the image-formed sheet material. Image forming apparatus.

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