JP4775037B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a printer.

  In an image forming apparatus such as an electrophotographic copying machine or printer, the paper generated by the heat of the fixing unit may be curled, and as a result, the paper discharged outside the machine is not properly aligned and accommodated on the paper discharge tray. There's a problem. In particular, when the paper is curved in the paper traveling direction, it greatly affects the paper storage capacity on the paper discharge tray. When the degree of curling is large, the paper discharged first and the paper discharged next are In some cases, the sheet may collide and be bent, or the sheet may fall from the sheet discharge tray.

  In order to improve such a problem, a pair of rollers including a paper discharge roller 5_1 and a corrugation roller 5_2 as shown in FIGS. 6 and 7 are used as the feed roller 5 of the image forming apparatus.

  FIG. 6 is a cross-sectional view of a delivery roller using a corrugation roller, and FIG. 7 is a perspective view of the delivery roller using a corrugation roller.

  6 and 7, the paper discharge roller 5_1 composed of a plurality of individual rollers 5_1a arranged at intervals in the width direction of the paper P and the plurality of individual rollers 5_1a constituting the paper discharge roller 5_1 are rotating shafts. A sheet P that is composed of a pair of rollers composed of a plurality of corrugation rollers 5_2 that are arranged at intervals in different directions and that is sandwiched between the paper discharge roller 5_1 and the corrugation roller 5_2. The feed roller 5 is shown in which the cross section in the width direction is passed while being deformed into a waveform.

  However, when such a corrugation roller is used as the paper discharge device of the image forming apparatus, the following problems occur. That is, normally, the paper discharge device of the image forming apparatus is usually arranged on the downstream side of the fixing device and in the vicinity of the discharge port on the upper part of the image forming apparatus. When trying to design the device, the paper feeding direction of the fixing unit and the paper feeding direction of the corrugation roller are arranged in different directions, and the paper transport path from the fixing unit to the corrugation roller is tightly curved There is a case where it must be.

  In the image forming apparatus having such a layout, a curved paper guide is provided to guide the leading edge of the paper fed from the fixing unit to the paper discharge roller. The trailing edge of the paper is strongly pressed against the curved portion of the paper guide. Therefore, a noise called a scratching sound is generated. In particular, when the corrugation roller described above is used for the paper discharge unit, the bending stiffness in the paper traveling direction increases due to the corrugation. A rubbing sound is generated.

  In addition, when the paper that has been conveyed while being strongly pressed against the paper guide passes the downstream end of the paper guide in the paper traveling direction, the trailing edge of the paper that has been pressed against the curved portion of the paper guide until then is Since it is abruptly played, an impulsive noise called a trailing edge splash is generated. There is a strong demand for reducing the trailing edge splashing noise as well as the above-mentioned rubbing noise.

  As a method for reducing the above-mentioned rubbing noise, for example, a flexible film member is disposed as a paper guide, and a chevron rib is provided on the paper sliding surface of the flexible film member to increase the contact area between the paper guide and the paper. There is disclosed a paper transport device that reduces the scratching noise by reducing it (see, for example, Patent Document 1).

  However, even if this method can reduce the scratching noise, it cannot be expected to reduce the trailing edge splashing sound.

As a method of reducing the trailing edge splashing sound, for example, in a sheet conveying apparatus that pulls out a sheet from a sheet tray and conveys the sheet downstream, a sheet loop is formed with a sheet loop formed between two sheet conveying rollers. In order to reduce the back-up splashing sound that occurs when the rear end of the paper is released from the nip of the upstream paper transport roller, A curved guide portion composed of two swing guide plates is provided, and when the loop of paper is formed, the rear end springs by swinging in the direction in which the two swing guide plates escape from the pressure. A paper conveying device that reduces noise is disclosed (for example, see Patent Document 2).
JP 2003-81482 A JP 07-315622 A

  However, even if the method disclosed in Patent Document 2 is applied to the paper discharge device of the image forming apparatus, it is difficult to apply because the accuracy of guiding the leading edge of the paper discharged from the fixing device to the nip portion of the feed roller is low. . In addition, the method disclosed in Patent Document 2 has a problem in that it has a large number of components and the structure is complicated, so that the cost is likely to increase.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a low-cost image forming apparatus in which noise during sheet feeding is reduced.

The image forming apparatus of the present invention that achieves the above object provides:
In an image forming apparatus for forming a toner image based on image information on a sheet, fixing the toner image on the sheet by heating, and forming an image composed of the fixed toner image on the sheet.
A fixing device for fixing the toner image;
The paper discharge roller composed of a plurality of individual rollers arranged at intervals in the paper width direction and the plurality of individual rollers constituting the paper discharge roller are arranged at intervals at different positions in the rotation axis direction. And a corrugation roller composed of a pair of individual rollers, and a feeding roller for feeding out the paper on which the toner image is fixed by the fixing device to the outside while deforming the cross section in the width direction of the paper into a waveform. When,
A paper guide that guides the paper that has traveled via the fixing device along a curved guide path from the fixing device to the delivery roller;
The paper guide has a cross-sectional shape substantially the same as a paper shape deformed by the delivery roller.

  In the image forming apparatus according to the present invention, the sheet fed by the feeding roller composed of the paper discharge roller and the corrugation roller to the sheet guide guided along the curved guide path from the fixing device to the feeding roller is wide. The cross section of the paper is deformed into a wave shape and the bending stiffness in the paper traveling direction is increased, and the trailing edge of the paper is pressed against the curved portion of the paper guide, but the paper guide is almost the same cross-sectional shape as the paper shape deformed by the feed roller Therefore, the pressing force at the rear end of the paper becomes very small, and therefore, the noise generated by the curved portion of the paper guide and the rear end of the paper is reduced.

  In addition, since the paper guide has substantially the same cross-sectional shape as the paper shape deformed by the delivery roller, the pressing force of the paper against the guide member is alleviated, and the occurrence of trailing edge noise is also suppressed.

  Here, the paper guide is composed of a guide member on the large diameter side and a guide member on the small diameter side of the guide path that forms the guide path, and only the guide member on the large diameter side is deformed. It is preferable that it has a cross-sectional shape substantially the same as the paper shape.

  When the image forming apparatus of the present invention is configured as described above, an image forming apparatus with reduced noise during sheet feeding can be configured at a lower cost.

  According to the present invention, it is possible to realize a low-cost image forming apparatus in which noise during sheet feeding is reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 forms a toner image based on image information on a sheet P, and fixes the toner image on the sheet by heating the toner image. An image forming unit for forming a toner image based on image information on a sheet tray 2 for storing the sheet P and a toner image based on the image information on the sheet P, a developing unit 3c, and a transfer unit 3d. An image forming unit 3 composed of a toner image, a fixing device 4 for fixing the toner image, and a paper P on which the toner image is fixed by the fixing device 4 are transformed outside the apparatus and the cross section in the width direction of the paper P is transformed into a waveform. The feed roller 5 that feeds out the paper and the paper guide 6 that guides the paper P that has traveled via the fixing device 4 along a curved guide path 8 that leads from the fixing device 4 to the feed roller 5.

  In this embodiment, the delivery roller 5 has a discharge roller composed of a plurality of individual rollers arranged at intervals in the paper width direction, and a plurality of individual rollers constituting the discharge roller at different positions in the rotation axis direction. It consists of a pair of roller comprised from the corrugation roller which consists of a several separate roller arrange | positioned at intervals. Details of the delivery roller 5 will be described later with reference to FIGS.

  The paper guide 6 has a cross-sectional shape substantially the same as the paper shape deformed by the feed roller 6.

  The paper guide 6 includes a guide member 6_1 on the large diameter side of the guide path 8 forming the guide path 8 and a guide member 6_2 on the small diameter side, and the guide member on the large diameter side. Only 6_1 may be configured to have substantially the same cross-sectional shape as the deformed paper shape.

  FIG. 2 is a schematic diagram of a paper guide and a delivery roller in the present embodiment.

  FIG. 2 includes a paper discharge roller 5_1 and a corrugation roller 5_2 that send out the paper P, on which the toner image has been fixed by the fixing device 4, to the outside of the apparatus while deforming the cross section in the width direction of the paper P into a waveform. A paper guide 6 that guides the feeding roller 5 and the paper P that has traveled via the fixing device 4 along a curved guide path 8 from the fixing device 4 to the feeding roller 5 is shown.

  FIG. 3 is a detailed view of the paper guide and the delivery roller in the present embodiment.

  FIG. 3 shows detailed configurations of the feed roller 5 and the paper guide 6 shown in FIG.

  As shown in FIG. 3, the delivery roller 5 includes a discharge roller 5_1 composed of a plurality of individual rollers 5_1a arranged at intervals in the paper width direction, and a plurality of individual rollers constituting the discharge roller. It consists of a pair of roller comprised from the corrugation roller 5_2 which consists of the several separate roller 5_2a arrange | positioned in the position where a rotating shaft direction differs at intervals.

  The roller shaft 5_1c of the paper discharge roller 5_1 and the individual roller 5_2a of the corrugation roller 5_2 are in contact with each other to form a nip portion N. The sheet is sent out while the cross section in the width direction is deformed into a waveform by the nip portion N.

  FIG. 4 is a diagram illustrating the shape of the sheet after being fed from the feeding roller according to the present embodiment.

  The leading edge of the paper P sent out from the fixing device 4 is sent to the sending roller 5 by a large-diameter side guide member 6_1 (see FIG. 2), and the paper traveling direction is changed by the paper discharge roller 5_1 and the corrugation roller 5_2 of the sending roller 5. The paper is fed while corrugation is formed in the intersecting paper width direction.

  FIG. 5 is a diagram showing a cross-sectional shape of the paper guide in the present embodiment.

  FIG. 5A shows a cross-sectional shape of the paper guide 6 viewed from the feeding roller 5 side when it is formed by bending a metal plate or the like, and FIG. 5B shows a plastic molded product. A cross-sectional shape of the paper guide 6 ′ viewed from the delivery roller 5 side is shown.

  As shown in FIGS. 5 (a) and 5 (b), the paper guides 6 and 6 ′ are formed from a large-diameter side guide member 6_1 and a small-diameter side guide member 6_2 of the guide path 8 (see FIG. 1). Thus, only the guide member 6_1 on the large diameter side has substantially the same cross-sectional shape as the paper shape after being deformed by the delivery roller 5 (see FIG. 4).

  The large-diameter guide member 6_1 is illustrated in accordance with the arrangement of the plurality of individual rollers 5_2a of the corrugation roller 5_2 in order to guide the leading end of the sheet to the nip portion N (see FIG. 3) of the delivery roller 5. As described above, a convex portion 6_1a protruding downward and a concave portion 6_1b recessed downward are formed.

  The step H1 between the convex portion 6_1a and the concave portion 6_1b is set to a height that can absorb the corrugation height H2 (see FIG. 4) generated on the paper by the feed roller 5, that is, a height equal to or higher than the corrugation height H2. .

  Note that the end in the sheet width direction of the concave portion 6_1b of the guide member 6_1 on the large diameter side has a height substantially equal to the nip portion N formed by the roller shaft 5_1c of the paper discharge roller 5_1 and the individual roller 5_2a of the corrugation roller 5_2. Therefore, the leading edge of the paper is smoothly guided to the nip portion N (see FIG. 3) of the feed roll 5 by the concave portion 6_1b of the large diameter side guide member 6_1.

  As described above, the paper guide of the present invention may be formed by bending a metal plate or the like, or may be formed as a plastic molded product. When formed by bending a metal plate or the like, there is an advantage that the manufacturing is easy and the cost is low, and when it is formed as a plastic molded product, as shown in FIG. 5 (b), the rib-like convex portion 6_1a is formed. It is easy to form the large-diameter side guide member 6_1, and by making the convex portion 6_1a into a rib shape, the contact area with the front end of the paper can be reduced, which is effective in suppressing the fraying noise.

  As described above with reference to FIGS. 5 and 4, the bending stiffness in the paper traveling direction increases due to the formation of the corrugation by the feeding roller 5, but the corrugation is not provided in the large diameter guide member 6 </ b> _ <b> 1 (see FIG. 5). Since the concave portion 6_1b is provided in accordance with the arrangement of the individual rollers 5_2a (see FIG. 5) of the roller 5_2, the paper convex portion Pa (see FIG. 4) formed by corrugation is the concave portion 6_1b (FIG. 5) of the guide member 6_1. See) and does not contact the guide member 6_1. Moreover, even if it contacts the guide member 6_1, the pressing force is very small. Note that when the leading edge of the sheet is guided, the leading edge of the sheet and the guide member 6_1 are only in contact with the sheet convex portion Pa. Since the contact area is small, the generation of scratching noise is greatly suppressed.

  Further, even when the rear end of the sheet passes through the large diameter side guide member 6_1, the sheet convex portion Pa is not strongly pressed against the large diameter side guide member 6_1.

  Note that the corrugation of the paper on the downstream side of the delivery roll 5 does not affect the subsequent conveyance of the paper, and the paper discharge tray 7 (see FIG. 1) with the paper having sufficient bending strength in the traveling direction. Well aligned and housed on top.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a schematic diagram of a paper guide and a delivery roller in the present embodiment. It is a detailed view of a paper guide and a delivery roller in the present embodiment. It is a figure which shows the shape of the paper sent out by the sending roller of this embodiment. It is a figure which shows the cross-sectional shape of the paper guide in this embodiment. It is sectional drawing of the sending roller using a corrugation roller. It is a perspective view of a sending roller using a corrugation roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper tray 3 Image forming unit 3a Charger 3b Latent image forming part 3c Developing part 3d Transfer part 4 Fixing device 5 Feeding roller 5_1 Discharge roller 5_1a Individual roller 5_2 Corrugation roller 5_2a Individual roller 6, 6 'Paper guide 6_1, 6_2 Guide member 6_1a Convex part 6_1b Concave part 7 Paper discharge tray 8 Guide path

Claims (1)

In an image forming apparatus for forming a toner image based on image information on a sheet, fixing the toner image on the sheet by heating, and forming an image composed of the fixed toner image on the sheet.
A fixing device for fixing the toner image;
The paper discharge roller composed of a plurality of individual rollers arranged at intervals in the paper width direction and the plurality of individual rollers constituting the paper discharge roller are arranged at intervals at different positions in the rotation axis direction. And a corrugation roller composed of a pair of individual rollers, and a feeding roller that sends out a sheet on which a toner image has been fixed by the fixing unit to the outside of the apparatus while deforming a cross section in the width direction of the sheet into a waveform. When,
A paper guide that guides the paper that has traveled through the fixing device along a curved guide path from the fixing device to the delivery roller, and forms the guide path. A paper guide composed of a guide member on the large diameter side and a guide member on the small diameter side,
The large-diameter side guide member has a cross-sectional shape in which substantially the same cross-sectional shape as the paper shape deformed by the feeding roller is continuous from the upstream end to the downstream end along the paper advance direction. An image forming apparatus.

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