JP2007168978A - Paper feed cassette, and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feed cassette with a shuffling roller built therein which is capable of preventing any oblique conveyance of a paper sheet during the paper feed operation. <P>SOLUTION: A pair of right and left auxiliary guides 15a, 15b for guiding both ends of a paper sheet P to be conveyed to the position over the shaft center of a shuffling roller 33 are mounted on side guides 12a, 12b. From the viewpoint of facilitating the work when changing the size of the paper sheets to be stored, the side guides 12a, 12b are preferably mounted on an inner bottom face of a cassette body 11 slidably in the width direction of the paper sheets. Further, from the viewpoint of enhancement of the handling property and the workability, the auxiliary guides 15a, 15b are preferably integrated with the side guides 12a, 12b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet feeding cassette and an image forming apparatus, and more particularly to a sheet feeding cassette having a separation roller and an image forming apparatus using the same.

  A conventional paper feed cassette is shown in FIG. A conventional paper feed cassette 1 ′ includes a cassette body 11, a pair of side guides (width regulating members) 12 a and 12 b that are attached to the inner bottom surface of the cassette body 11 and regulate the width direction of the paper P, and the paper P A back guide (rear end regulating member) 13 for regulating the rear end is provided. The side guides 12a and 12b are slidable in the width direction of the paper according to the paper size. The back guide 13 is also slidable according to the paper size. An area surrounded by the side guides 12a and 12b and the back guide 13 is a sheet placement area. A lifting plate 14 is attached to the sheet placement area so as to be swingable about the pin 10. A separating roller 33 is attached to the front wall of the cassette body 11 in the transport direction.

  As shown in FIG. 6, when the paper P is placed in the paper placement area of the paper feed cassette 1 ′ and the paper feed cassette 1 ′ is mounted on the image forming apparatus main body, the lifting plate 14 is raised and placed. The leading end side of the paper P in the paper feeding direction is lifted upward. The uppermost sheet comes into contact with the pickup roller 31 attached to the image forming apparatus main body. At the same time, the paper feed roller 32 and the separating roller 33 attached to the image forming apparatus main body are brought into pressure contact with each other.

  When image formation is started, the paper P is first drawn in the direction of the conveyance path by the rotation of the pickup roller 31. Then, the sheet feed roller 32 and the separation roller 33 feed the sheets one by one to the conveyance path.

  Here, as shown in FIG. 5, when a large sheet such as A3 size or B4 size is used, in the conventional sheet feeding cassette 1 ′, when the sheet P is pulled out by the pickup roller 31, the trailing end of the sheet P As a result, the paper P may become slanted. When the paper P is transported obliquely, it causes a paper transport failure and an image failure.

Therefore, for example, Patent Document 1 proposes a technique for forming the skew prevention portion integrally with the side guide.
JP-A-5-139560

  However, the proposed technology does not consider a paper feed cassette with a built-in separation roller, and the proposed technology cannot be applied to such a paper feed cassette.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to prevent oblique conveyance of paper during paper feeding in a paper feeding cassette incorporating a separating roller.

  In order to achieve the above object, in the paper feed cassette of the present invention, a cassette main body for storing paper, a pair of left and right width regulating members attached to the inner bottom surface of the cassette main body for regulating the paper position in the width direction, and the cassette main body A pair of left and right guide members for guiding both side edges of the conveyed paper to a position beyond the center of the shaft of the separation roller. It is attached to.

  Here, from the viewpoint of facilitating work when changing the size of the paper to be stored, the pair of left and right width regulating members are preferably attached to the inner bottom surface of the cassette body so as to be slidable in the paper width direction. .

  Moreover, it is preferable to form the guide member integrally with the width regulating member from the viewpoint of improving the handleability and workability.

  The image forming apparatus of the present invention includes an apparatus main body and a paper feed cassette that is detachably attached to the apparatus main body. The paper feed cassette is provided on a cassette main body for storing paper and an inner bottom surface of the cassette main body. A pair of left and right width regulating members for regulating the paper position in the width direction, a separating roller attached to the front side of the cassette body in the paper feeding direction, and a pair of left and right width regulating members, A pair of left and right guide members for guiding both side edges of the conveyed paper to a position beyond the axis center, and the apparatus body has a pickup roller that draws out in the direction of the conveyance path of the paper stored in the paper feed cassette; And a paper feed roller that presses the separation roller when the paper feed cassette is mounted and feeds the drawn paper out to the transport path.

  In the paper feed cassette and the image forming apparatus according to the present invention, the pair of left and right guide members that guide both side edges of the conveyed paper to a position beyond the center of the axis of the separating roller are attached to the pair of left and right width regulating members. In this way, the oblique conveyance of the paper during feeding is effectively prevented. This prevents paper conveyance failure and image failure.

  If the pair of left and right width regulating members are attached to the inner bottom surface of the cassette body so as to be slidable in the width direction of the paper, the movement of the width regulating member when changing the size of the paper to be stored is facilitated.

  In addition, when the guide member is formed integrally with the width regulating member, handling and workability can be improved.

  Hereinafter, an image forming apparatus and a paper feed cassette according to the present invention will be described with reference to the drawings. The present invention is not limited to these embodiments.

  FIG. 1 is a schematic view showing an embodiment of the image forming apparatus of the present invention. The image forming apparatus in FIG. 1 is a schematic cross-sectional view of an image forming apparatus in which a paper feed cassette 1 of the present invention is mounted. The surface of the photosensitive drum 70 is uniformly charged positively or negatively by a charging device 71. On the other hand, a document (not shown) is placed on a document placing table 90 covered with a lid 91, and the image data is read by a reading device (not shown). The read image data is written on the surface of the photosensitive drum 70 by a laser scanner (exposure device) 72, and an electrostatic latent image is formed on the surface of the photosensitive drum 70. Specifically, in the case of the reverse development method, the charge corresponding to the image is removed, and in the case of the regular development method, the charge corresponding to the background is removed to form an electrostatic latent image. Next, the electrostatic latent image on the photosensitive drum 70 is visualized with toner by the developing device 73. At this time, the charging polarity of the toner is the same as the charging polarity of the photosensitive drum 70 in the case of the reversal development method, and is opposite to the charging polarity of the photosensitive drum 70 in the case of regular development.

  On the other hand, the paper P stored in the paper feed cassette 1 is pulled out by the pickup roller 31, is sandwiched between the paper feed roller 32 and the separating roller 33 that are pressed against each other, and is sent to the transport path. Then, the registration roller pair 81 feeds the paper P to the transfer unit in time with the toner image on the photosensitive drum 70 reaching the transfer unit. In the transfer portion, the sheet P is sandwiched between the photosensitive drum 70 and the transfer roller 74, and a charge having a polarity opposite to the toner charging polarity is applied to the transfer roller 74. Toner image moves onto the paper P. The toner remaining on the photosensitive drum 70 without moving onto the paper P is removed and collected by the cleaning roller 75. On the other hand, the paper P on which the toner image is placed is conveyed to the fixing roller pair 85. Here, the toner image is heated and pressurized by the fixing roller pair 85 and fixed on the paper P. Then, the paper P is discharged onto the paper discharge tray 87 by the discharge roller pair 86.

  FIG. 2 is a perspective view of a paper feed cassette used in the image forming apparatus of FIG. The paper feed cassette 1 of FIG. 2 includes a box-shaped cassette body 11 having an upper surface opening, and a pair of side guides 12 a and 12 b attached to the inner bottom surface of the cassette body 11 and a back guide 13. The side guides 12a and 12b and the back guide 13 are slidably attached to the cassette body and are moved in accordance with the size of the paper to be placed. Specific examples of the mechanism for sliding the side guides 12a and 12b include the following. A pair of racks (not shown) are attached point-symmetrically with respect to the gear shaft so as to mesh with a gear (not shown) pivotally supported below the inner bottom surface of the cassette body 11. The side guides 12a and 12b are suspended from the pair of racks. According to this mechanism, for example, when one side guide is moved inward in the width direction, the other side guide is also moved inward in the width direction by the cooperative action of the rack and the gear. This narrows the width between the side guides. Conversely, when one side guide is moved outward in the width direction, the other side guide is also moved outward in the width direction, and the width between the side guides is increased. In this way, by moving one side guide, the other side guide can be moved at the same time, and the width of the side guide can be changed quickly according to the size of the paper, centered in the width direction. it can.

  The paper P is placed in a paper placement area surrounded by the side guides 12 a and 12 b and the back guide 13. At this time, the position of the sheet in the width direction is regulated by the side guides 12a and 12b, and the position of the trailing edge of the sheet is regulated by the back guide 13. A lifting plate 14 is attached to the paper placement area so as to be swingable about a pin (not shown). When the paper feed cassette 1 is mounted on the apparatus main body, the elevating plate 14 lifts the paper upward, and the uppermost paper comes into contact with the pickup roller 31 (shown in FIG. 1).

  As shown in FIGS. 2 and 3, a pair of thin auxiliary guides (guide members) 15 a and 15 b bent along the sheet conveying surface are provided on the upper side of the side guides 12 a and 12 b in the paper feeding direction. It is attached. When the side guides 12a and 12b are slid according to the paper size, the auxiliary guides 15a and 15b are also moved together. In this embodiment, the auxiliary guides 15a and 15b are formed integrally with the side guides 12a and 12b. However, the auxiliary guides 15a and 15b may be joined after being formed separately.

  In many cases, the sheet is slanted until it is pulled out by the pickup roller 31 and is nipped by the sheet feeding roller 32 and the separating roller 33. Therefore, as shown in FIG. 4, the front ends of the auxiliary guides 15 a and 15 b in the sheet feeding direction are extended to a position beyond the center of the separating roller 33, and the sheet is sandwiched between the sheet feeding roller 32 and the separating roller 33. Until it is done, it is important to guide both side edges of the paper with the auxiliary guides 15a and 15b. Thus, the position of both sides of the sheet is regulated by the pair of auxiliary guides 15a and 15b until the sheet is pulled out by the pickup roller 31 and is sandwiched between the sheet feeding roller 32 and the separating roller 33 and sent to the conveyance path. Thus, the oblique feeding of the paper is reliably prevented. It should be noted that the position of the auxiliary guides 15a, 15b at the front end in the paper feeding direction is preferably extended long beyond the center of the separation roller 33 within a range that does not hinder attachment / detachment of the paper feeding cassette to / from the apparatus main body.

  The height of the auxiliary guides 15a and 15b is not particularly limited as long as both side edges of the conveyed paper can be regulated, and it is usually desirable that the auxiliary guides 15a and 15b be close to the height of the paper conveyance path. The material of the auxiliary guide is not particularly limited, and conventionally known materials such as plastic and metal can be used.

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a perspective view which shows an example of the paper feed cassette which concerns on this invention. FIG. 3 is a partially enlarged perspective view of the paper feed cassette of FIG. 2. It is a figure for demonstrating the position of the paper feed direction front end of an auxiliary guide. It is a top view of the conventional paper feed cassette. It is a schematic diagram which shows the paper feed from the conventional paper feed cassette.

Explanation of symbols

1 Paper cassette P Paper 11 Cassette body 12a, 12b Side guide (width regulating member)
13 Back guide 15a, 15b Auxiliary guide (guide member)
31 Pickup roller 32 Paper feed roller 33 Separation roller

Claims (4)

A cassette main body for storing paper, a pair of left and right width regulating members for regulating the paper position in the width direction attached to the inner bottom surface of the cassette main body, and a separating roller attached to the front side of the cassette main body in the paper feeding direction. ,
A paper feed cassette, wherein a pair of left and right guide members for guiding both side edges of the conveyed paper to a position beyond the axis center of the separating roller are attached to the pair of left and right width regulating members.   2. The paper feed cassette according to claim 1, wherein the pair of left and right width regulating members are attached to the inner bottom surface of the cassette body so as to be slidable in the paper width direction.   The paper feed cassette according to claim 1 or 2, wherein the guide member is formed integrally with the width regulating member. In an image forming apparatus having an apparatus main body and a paper feed cassette detachably attached to the apparatus main body,
The paper feed cassette is attached to the cassette main body for storing paper, a pair of left and right width regulating members attached to the inner bottom surface of the cassette main body for regulating the paper position in the width direction, and the cassette main body in front of the paper feed direction. A separation roller, and a pair of left and right guide members that are attached to the pair of left and right width regulating members and guide both side edges of the conveyed paper to a position that exceeds the axial center of the separation roller;
The main body of the apparatus feeds out the drawn paper to the transport path by pressing the pick-up roller that pulls out the paper stored in the paper feed cassette in the direction of the transport path and the separation roller when the paper feed cassette is mounted. An image forming apparatus comprising: a roller.

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