JP2013037284A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which can suppress bending of a corner of a curled sheet when it contacts with a detecting member.SOLUTION: The image forming apparatus comprises: a detection member 200 which is swung by contacting with a sheet conveyed in a conveyance path; and a detection sensor (an optical sensor 300) which detects swinging of the detection member 200. The detection member 200 includes: a contacted piece (a first member 210) which contacts with an intermediate part of the sheet; a rotating shaft 222 which extends from the contacted piece side to the outside in the width direction; and an opposite part 223 which is provided on the outer end in the width direction of the rotating shaft 222 and faces the end in the width direction of the sheet. The opposite part 223 is formed so that an outer part on the outside in the width direction of the opposite part 223 (a second inclined surface 223B) is away from the sheet more than an inner part on the inside in the width direction (a first inclined surface 223A) when viewed from the conveyance direction of the sheet at the maximum swinging of the contacted piece caused by being pushed by the sheet.

Description

  The present invention relates to an image forming apparatus including a detection member for detecting passage or presence of paper.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus that includes a detection member that swings by abutting against a sheet transported in a transport path, and an optical sensor that detects swing of the detection member (see Patent Document 1). . Specifically, the detection member in this technology is provided at a lever portion provided at the center in the width direction of the paper, a rotation shaft extending outward in the width direction from the lever portion, and an end portion in the width direction outer side of the rotation shaft, A shielding plate capable of shielding light from the optical sensor.

  In this technique, when the paper transported in the transport path comes into contact with the lever portion, the shielding plate swings together with the lever portion and moves out of the optical path of the optical sensor so that the passage of the paper is detected by the optical sensor. It has become.

JP 2008-158507 A

  By the way, in the structure in which the detection member is formed so as to extend from the central portion in the width direction to the outside in the width direction as in the past, if the corner portion on the leading end side of the paper is curled, this corner portion is the width direction of the detection member. There was a problem that it hits an outer end (for example, a shielding plate) and breaks.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of suppressing the corner of a curled sheet (sheet) from abutting against a detection member and bending.

In order to solve the above problems, an image forming apparatus according to the present invention includes an apparatus main body in which a conveyance path through which a sheet passes is formed, and a sheet that is swingably provided in the apparatus main body and is conveyed in the conveyance path. A detection member that swings by contact and a detection sensor that detects the passage or presence of the sheet by detecting the swing of the detection member.
The detection member includes a contact piece that abuts on an intermediate portion located between both widthwise ends of the sheet, a rotation shaft that extends outward in the width direction from the contact piece side, and a width of the rotation shaft. A counter portion provided at an end portion on the outer side in the direction and facing an end portion in the width direction of the sheet; and a detected piece provided on the rotating shaft and detected by the detection sensor.
The opposing portion has an outer portion on the outer side in the width direction of the opposing portion when viewed from the conveyance direction of the sheet at the maximum swinging time when the contacted piece is pressed by the sheet and swings to the maximum. It forms so that it may leave | separate from the said sheet | seat rather than the inner side part of the width direction inner side.

  According to this configuration, the outer portion of the facing portion facing the end portion in the width direction of the sheet is formed so as to be farther from the sheet than the inner portion, so that the corner on the leading end side of the end portion of the sheet is curled. Even in such a case, it is difficult for the corners of the sheet to come into contact with the facing portion, so that the corners of the sheet can be prevented from being broken.

  Further, in the above-described configuration, the inner portion is a first inclined surface that approaches the sheet toward the downstream side in the conveyance direction at the time of the maximum swing, and the outer portion is transported at the time of the maximum swing. It is desirable that the second inclined surface be closer to the sheet toward the downstream side in the direction and have a larger angle than the angle of the first inclined surface with respect to the conveyance direction.

  According to this, since the end portion of the curled sheet can be brought close to the position of the center portion of the sheet by the second inclined surface having an angle larger than that of the first inclined surface, the curl of the sheet can be corrected.

  Further, in the above-described configuration, the end portion on the outer side in the width direction of the second inclined surface is formed so as to incline toward the outer side in the width direction from the upstream side to the downstream side in the transport direction at the time of the maximum swing. It is desirable that a third inclined surface that further inclines in a direction away from the sheet from the end portion on the outer side in the width direction of the second inclined surface toward the outer side in the width direction is further provided during the maximum swing.

  According to this, it is possible to suppress the end portion of the curled sheet from rubbing against the end portion of the second inclined surface by the third inclined surface. Further, since the end portion of the curled sheet is pushed and spread by the third inclined surface, the curling of the sheet can be further corrected.

  Further, in the above-described configuration, the abutted piece is constituted by a member different from the rotating shaft, the facing portion, and the detected piece, and is supported by the apparatus main body so as to be swingable. It is desirable that a link portion that swings in conjunction with the abutted piece by being engaged with the abutted piece is provided.

  According to this, since the member having the detected piece or the like and the contacted piece are separate members, for example, a material that easily detects the member having the detected piece or the like by the detection sensor (for example, a member having a high light shielding property). Thus, the abutted piece can be made a highly slidable member.

  In the above-described configuration, it is preferable that the detected piece and the detection sensor are arranged on the side opposite to the sheet in the inner portion at the time of the maximum swing.

  According to this, since the detected piece and the detection sensor are provided in the space on the back side of the inner part, which is wider than the space on the back side (the side opposite to the sheet) of the outer part, the space can be used effectively, and the device Can be miniaturized.

  According to the present invention, it is possible to suppress the corner of the curled sheet from being in contact with the detection member and being bent.

1 is a cross-sectional view illustrating a color printer according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a state where a manual feed tray is opened. It is a perspective view showing a manual paper feed mechanism. FIG. 6 is a perspective view of an upper frame of the manual sheet feeding mechanism as viewed from below. It is a disassembled perspective view which shows the state which removed the detection member from the upper frame. They are the perspective view (a) which looked at the 1st member from the left side, and the perspective view (b) which looked at the 2nd member from the upper part. They are sectional drawing (a) which shows the state of the detection member before inserting a sheet | seat in an insertion port, and sectional drawing (b) which shows the state after inserting a sheet | seat.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, the overall configuration of a color printer as an example of an image forming apparatus will be briefly described, and then the characteristic portions of the present invention will be described in detail.

  In the following description, the direction will be described with reference to the user when using the color printer. That is, in FIG. 1, the left side toward the paper surface is “front side (front side)”, the right side toward the paper surface is “rear side (back side)”, the back side toward the paper surface is “left side”, and it faces the paper surface. Let the near side be the “right side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the color printer 1 includes, in the apparatus main body 10, a paper feeding unit 20 that supplies paper P as an example of a sheet, and an image forming unit 30 that forms an image on the fed paper P. And a paper discharge section 90 for discharging the paper P on which the image is formed.

  The paper feeding unit 20 is provided in the lower part of the apparatus main body 10, and a paper feeding tray 21 that is detachably attached to the apparatus main body 10, and a paper supply mechanism that conveys the paper P from the paper feeding tray 21 to the image forming unit 30. 22. In the paper supply unit 20, the paper P in the paper supply tray 21 is separated one by one by the paper supply mechanism 22 and supplied to the image forming unit 30.

  The image forming unit 30 includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing device 80.

The LED unit 40 includes a plurality of LEDs in order to expose the photosensitive drum 53.
The process cartridge 50 includes a photosensitive drum 53, a known charger, a developing roller, a toner storage chamber, and the like that are not shown.

The transfer unit 70 is provided between the paper feeding unit 20 and each process cartridge 50, and includes a driving roller 71, a driven roller 72, a belt 73, and a transfer roller 74.
The fixing device 80 includes a heating roller 81 and a pressure roller 82 that is disposed to face the heating roller 81 and presses the heating roller 81.

  In the image forming unit 30 configured as described above, first, the surface of each photosensitive drum 53 is uniformly charged by a charger and then exposed by each LED unit 40. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed on each photosensitive drum 53. Thereafter, toner is supplied to the electrostatic latent image from the developing roller, so that the toner image is carried on the photosensitive drum 53.

  Next, the paper P supplied onto the belt 73 passes between each photosensitive drum 53 and each transfer roller 74, so that the toner image formed on each photosensitive drum 53 is transferred onto the paper P. . Then, as the paper P passes between the heating roller 81 and the pressure roller 82, the toner image transferred onto the paper P is thermally fixed.

  The paper discharge unit 90 includes a plurality of pairs of transport rollers 91 and a pair of paper discharge rollers 92. In the paper discharge unit 90, the paper P output from the fixing device 80 is transported by a plurality of pairs of transport rollers 91 and a pair of paper discharge rollers 92 and discharged to the discharge tray 11.

  A manual paper feed mechanism 100 is provided on the front side of the apparatus main body 10. The manual feed mechanism 100 includes a manual feed tray 12 (see FIG. 2) that can swing relative to the apparatus main body 10 and a supply roller 110 that conveys the paper P placed on the manual feed tray 12 toward the apparatus main body 10. And a separation roller 120 and a separation pad 121 for separating the overlapped sheets P one by one when the sheets P are fed from the supply roller 110 in an overlapped state.

  As shown in FIG. 2, the manual paper feeding mechanism 100 executes printing of the paper P on the manual tray 12 with the paper P placed on the manual tray 12 that has been tilted forward from the standing state. When a command to input is input, the supply roller 110 is lowered to contact the paper P. As the supply roller 110 in contact with the sheet P rotates in this way, the uppermost sheet P is supplied to the image forming unit 30 in the apparatus main body 10 via the separation roller 120 and the like. After feeding one sheet P, the supply roller 110 is returned to the upper standby position and held at this standby position until the next command is input.

<Structure of detection members, etc.>
Next, the structure of the detection member 200 and the like provided in the manual paper feed mechanism 100 will be described in detail with reference to FIGS.

  As shown in FIG. 3, the manual paper feed mechanism 100 includes the supply roller 110 and the separation roller 120 described above, a housing 130, a detection member 200, and an optical sensor 300 as an example of a detection sensor (FIG. 5). Reference).

  The housing 130 constitutes a part of the front side portion of the apparatus main body 10, and mainly includes an upper frame 131 and a lower frame 132. A conveyance path 140 through which the paper P passes is formed between the upper frame 131 and the lower frame 132.

  As shown in FIGS. 4 to 6, the detection member 200 is a member that swings by contacting the paper P that is transported in the transport path 140 described above, and is swingably supported by the upper frame 131. In the state, it is arranged in the transfer path 140 described above. Specifically, the detection member 200 includes a first member 210 as an example of a contact piece and a second member 220 that is a separate member from the first member 210.

  The first member 210 is a support shaft 131A provided at a substantially central portion in the left-right direction of the upper frame 131 (specifically, a position adjacent to the supply roller 110 provided at the center of the upper frame 131 in the left-right direction: see FIG. 3). Is swingably supported. As a result, the first member 210 comes into contact with an intermediate portion located between both ends in the left-right direction (width direction) of the paper P, so that it is pushed by the paper P and swings.

  Specifically, the first member 210 includes a bearing portion 211 that is rotatably supported by the support shaft 131A, and a main body portion 212 that is formed in a substantially fan shape that gradually spreads outward from the bearing portion 211 in the radial direction. And an arcuate link hole 213 that is formed so as to penetrate the main body portion 212 in the left-right direction and engages with a link portion 221 described later.

  The second member 220 includes a link portion 221, a rotation shaft 222 extending outward in the left-right direction from the link portion 221 (first member 210 side), and a facing portion 223 provided at an end portion of the rotation shaft 222 on the outer side in the left-right direction. And a detected piece 224 (see FIG. 6B) that is provided on the upper frame 131 side of the facing portion 223 and is detected by the optical sensor 300.

  The link portion 221 is formed so as to extend radially outward from the rotation shaft 222, and an engagement protrusion 221 </ b> A that slidably engages with the link hole 213 of the first member 210 is formed at the distal end portion thereof. Has been. As a result, as shown in FIGS. 7A and 7B, when the first member 210 pressed by the paper P inserted into the insertion port 101 of the manual paper feed mechanism 100 swings counterclockwise in the figure, When the engaging protrusion 221A is pushed by the link hole 213, the second member 220 swings in the clockwise direction in the figure in conjunction with the first member 210.

  In this way, the first member 210 and the second member 220 are swung in opposite directions to save space.

  Here, the first member 210 swings so as not to hinder the conveyance of the paper P regardless of whether the number of paper P inserted into the insertion slot 101 is one or the maximum number of sheets (for example, 50). It is necessary to increase the angle (range). On the other hand, after the second member 220 detects one sheet P (after the rear end of the sheet P is detached from the first member 210), the second member 220 is not so shaken so as not to hinder the conveyance of the sheet P. It is better that the moving angle does not change. Therefore, in the present embodiment, the link hole 213 of the first member 210 is formed in a shape such that the swing angle of the second member 220 is smaller than the swing angle (swing range) of the first member 210. ing.

  In addition, by making the first member 210 and the second member 220 as separate members in this way, the first member 210 with which the paper P abuts is formed of a highly slidable material and is detected by the optical sensor 300. The second member 220 including the detection piece 224 can be formed of a material having a high light shielding property. For example, polyacetal is exemplified as a material having high slidability, and black polycarbonate is exemplified as a material having high light shielding properties.

  The rotation shaft 222 is rotatably supported by a pair of bearing portions 131B provided on the upper frame 131.

  The facing portion 223 is provided at a position facing the edge in the left-right direction of the paper P, and is mainly a first inclined surface 223A as an example of an inner portion and a second inclined surface 223B as an example of an outer portion. And a third inclined surface 223C. The front end edge B1 of the second inclined surface 223B is formed in a step shape so as to be shifted upward from the front end edge A1 of the first inclined surface 223A when viewed from the conveyance direction (substantially front-rear direction) of the paper P.

  More specifically, the front edge B1 of the second inclined surface 223B is viewed from the transport direction when the first member 210 is swayed to the maximum when pressed by the paper P (see FIG. 7B). The first inclined surface 223A is formed so as to be farther from the paper P than the front end edge A1. As a result, even when the leading edge of the left and right ends of the paper P is curled, the corner of the paper P is unlikely to contact the front edge B1 of the second inclined surface 223B. It is possible to suppress the corner from breaking.

  Further, the first inclined surface 223A is slightly inclined with respect to the sheet P at the time of the maximum swing, and more specifically, is inclined so as to approach the sheet P toward the downstream side in the transport direction. On the other hand, the second inclined surface 223B approaches the paper P toward the downstream side in the transport direction at the maximum swing, and has a larger angle than the angle of the first inclined surface 223A with respect to the paper P (transport direction). Is formed.

  Thus, the left and right end portions of the curled paper P can be brought closer to the center of the paper P by the second inclined surface 223B having a larger angle than the first inclined surface 223A. It is possible to correct.

  Further, as shown in FIG. 5, the end B2 on the outer side in the left-right direction of the second inclined surface 223B is formed so as to incline toward the outer side in the left-right direction as it goes from the upstream side to the downstream side in the transport direction at the maximum swing. Has been. The third inclined surface 223C is formed so as to incline upward (in a direction away from the paper P) from the end B2 of the second inclined surface 223B toward the outer side in the left-right direction at the maximum swing.

  As a result, the third inclined surface 223C can suppress the end portion of the curled paper P in the left-right direction from rubbing against the end portion B2 of the second inclined surface 223B. Further, since the end portion of the curled paper P is pushed and spread by the third inclined surface 223C, the curling of the paper P can be further corrected.

  As shown in FIG. 6B, the detected piece 224 is disposed on the back side of the first inclined surface 223A (the side opposite to the paper P at the maximum swing), and detects the detected piece 224. The optical sensor 300 is also disposed on the back side of the first inclined surface 223A (see FIG. 5). As a result, the detected piece 224 and the optical sensor 300 are provided in the space behind the first inclined surface 223A, which is wider than the space behind the second inclined surface 223B. The paper mechanism 100 can be downsized.

  As shown in FIG. 5, the optical sensor 300 includes a light emitting unit 310 that emits light and a light receiving unit 320 that receives light emitted from the light emitting unit 310. The above-described detected piece 224 includes a position where the light emitted from the light emitting unit 310 is blocked (position in FIG. 7B) and a position where the light is retreated from the optical path of the light (position in FIG. 7A). To swing.

  As a result, the optical sensor 300 can detect the presence or absence of the paper P by detecting the swing of the detection member 200.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the embodiment, the detection member 200 is composed of two members, but the present invention is not limited to this and may be composed of one member. In the above embodiment, the present invention is applied to the detection member 200 provided in the conveyance path 140 in the manual sheet feeding mechanism 100. However, the detection member 200 is provided in the conveyance path from another detection member, for example, a paper feed tray to a paper discharge tray. The present invention may be applied to a detected member.

  In the above-described embodiment, the optical sensor 300 is exemplified as the detection sensor. However, the present invention is not limited to this, and may be, for example, a pressure sensor that contacts the detected piece. Further, the detection sensor is not limited to a sensor that detects the presence or absence of a sheet, and may be a sensor that detects the passage of a sheet.

  In the embodiment, the detected piece 224 is provided on the rotating shaft 222 via a part of the facing portion 223 (the wall having the first inclined surface 223A). However, the present invention is not limited to this, and the rotating shaft 222 The detected piece may be provided directly.

  In the above embodiment, the inner portion and the outer portion are inclined surfaces that are inclined with respect to the conveyance direction when the detection member is swung maximum, but the present invention is not limited to this. For example, the inner portion and the outer portion are conveyed. You may form in the plane along a direction.

  In the embodiment, the sheet P such as thick paper, postcard, and thin paper is exemplified as the sheet. However, the present invention is not limited to this, and may be, for example, an OHP sheet.

  In the above-described embodiment, the present invention is applied to the color printer 1, but the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as monochrome printers, copiers, and multifunction machines. Good.

DESCRIPTION OF SYMBOLS 1 Color printer 140 Conveyance path 200 Detection member 210 1st member 222 Rotating shaft 223 Opposite part 223A 1st inclined surface 223B 2nd inclined surface 224 Detected piece 300 Optical sensor P Paper

Claims (5)

An apparatus body in which a conveyance path through which the sheet passes is formed;
A detection member provided in the apparatus main body so as to be able to swing, and swinging by contact with a sheet transported in the transport path;
An image forming apparatus comprising: a detection sensor that detects passage or presence of the sheet by detecting swinging of the detection member;
The detection member is
A to-be-contacted piece that comes into contact with an intermediate portion located between both ends in the width direction of the sheet;
A rotating shaft extending outward in the width direction from the abutted one side;
An opposing portion that is provided at an end portion on the outer side in the width direction of the rotating shaft and faces an end portion in the width direction of the sheet;
A detection piece provided on the rotation shaft and detected by the detection sensor;
At the maximum swing when the abutted piece is pushed by the sheet and swings to the maximum, the outer portion on the outer side in the width direction of the facing portion is more than the inner portion on the inner side in the width direction when viewed from the sheet conveyance direction. The image forming apparatus is characterized in that the facing portion is formed so as to be separated from the sheet. The inner portion is a first inclined surface that approaches the sheet toward the downstream side in the conveyance direction at the time of the maximum swing,
The outer portion is a second inclined surface that approaches the sheet toward the downstream side in the conveying direction at the time of the maximum swing and has a larger angle than the angle of the first inclined surface with respect to the conveying direction. The image forming apparatus according to claim 1. The end portion on the outer side in the width direction of the second inclined surface is formed so as to incline toward the outer side in the width direction from the upstream side to the downstream side in the transport direction at the time of the maximum swing.
3. The third inclined surface is further provided that is inclined in a direction away from the sheet as it goes outward in the width direction from an end portion on the outer side in the width direction of the second inclined surface during the maximum swinging. The image forming apparatus described in 1. The abutted piece is composed of a member different from the rotating shaft, the facing portion, and the detected piece, and is supported by the apparatus main body so as to be swingable.
4. A link portion that swings in conjunction with the abutted piece by being engaged with the abutted piece is provided on the rotating shaft. The image forming apparatus according to claim 1. The image according to any one of claims 1 to 4, wherein the detected piece and the detection sensor are arranged on a side opposite to the sheet of the inner portion at the time of the maximum swing. Forming equipment.

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