JP2010202378A - Paper feeding tray and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding tray 10 of an image forming device that stably feeds paper sheets by smoothly pressing a sheet material A to a paper feeding roll 2 with enough pushing force of the sheet material A and prevents defects such as curvature of the sheet material A even when the stacked quantity of the sheet material A is low. <P>SOLUTION: Two pressing plates 7, 8 are provided on an end fence 6. The pressing plate 7 applies pressure with an elastic member 71 provided directly on the end fence 6, and the pressing plate 8 applies pressure with an elastic member 81 provided between the pressing plates 7, 8. A sheet material on a bottom plate 3 is pressed toward a sheet material tip regulating member 5 by the pressing plates 7, 8. The pressing force of the pressing plate 8 is varied depending on the rotating position of the pressing plate 7. When the pressing plate 7 is not in contact with the sheet material A, the pressing plate 7 holding the elastic member 81 with the pressing plate 8 is rotated. The pressing force of the elastic member 81 for pressing the pressing plate 8 is lowered, and therefore the pressing force of the pressing plate 8 for pressing the sheet material A is lowered. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a paper feed tray and an image forming apparatus mounted on an image forming apparatus such as a copying machine, a printer, and a facsimile machine.

  Conventionally, in a paper feeding device of an image forming apparatus, sheet materials are stacked on a bottom plate with their front and rear ends aligned. Further, the sheet material is pushed upward together with the bottom plate by an elastic force such as a spring, and is put between the sheet feeding roller and the bottom plate. In this state, the uppermost sheet material on the bottom plate is sent out by rotating the sheet feeding roller. At this time, the leading end portion of the sheet material is separated one by one by the separation portion, thereby being separated from the second and subsequent sheet materials, and conveyed to the next process for each sheet material.

  However, in the above-described conventional sheet feeding device, as the sheet material is sequentially fed from the bottom plate, the interval between the sheet material leading end regulating member and the leading end portion of the sheet material is gradually increased. For this reason, when the sheet material is reduced, misfeeds and double feeds are likely to occur, such as the leading edge of the sheet material being sandwiched between the sheet material leading edge regulating members and the uppermost sheet material being separated from the sheet feeding roller. There was a problem of becoming. This is a problem particularly in the case of a large capacity sheet feeding device in which a large amount of sheet material is stacked on the bottom plate.

  Therefore, as disclosed in Japanese Patent Laid-Open No. 9-67028 (Patent Document 1), a pressure plate that presses the rear end portion of the sheet material is provided on the end fence, and the pressure plate of the end fence is always the rear end portion of the sheet material. And the leading end of the sheet material is configured not to be separated from the sheet material leading end regulating member.

  Further, as disclosed in Japanese Patent Laid-Open No. 2000-95356 (Patent Document 2), in order to always keep the positional relationship between the sheet material front end regulating member and the front end of the stacked sheet material constant, There is a structure in which a variation in pressure mechanism due to the end fence is absorbed by using a pressure mechanism based on elastic pressure provided on the end fence and further deforming the sheet material front end restricting portion.

  Further, as disclosed in Japanese Patent Application Laid-Open No. 2002-80128 (Patent Document 3), the rotational angle of the bottom plate is suppressed by moving the position of the rotation fulcrum of the bottom plate according to the sheet material loading amount. There are some that do not need to press the sheet material rear end portion of the end fence by suppressing the variation in the distance between the sheet material front end regulating portion and the end fence.

  However, in Patent Document 1, when the sheet feeding tray is pulled out from the image forming apparatus, such as during sheet material stacking work, the bottom plate of the sheet feeding tray stands by at the lowest position. Regardless, the lower part of the stacked sheet material bundle is pushed out by the pressure plate of the end fence. When the bottom plate is at the bottom, the pressure plate of the end fence needs to push the sheet material bundle against the sheet material front end regulating member even in the heaviest state of the assumed sheet material loading capacity. When a small amount of sheet material is placed in the state, the pushing force from the pressure plate of the end fence is too strong, and the sheet material itself may be bent. If the sheet material itself bends, it will not be possible to move the leading edge of the sheet material to the sheet material leading edge regulating member, the feed roller and the sheet material will not come into contact, and problems such as non-feeding of the sheet material will occur. May end up.

  Moreover, in the thing of patent document 2, the malfunction mentioned above is not eliminated in the state in which the pushing-up action of the sheet | seat material rear end by the pressurization mechanism provided in the end fence does not fully work, such as the dispersion | variation in the fixing position of an end fence.

  Moreover, in the thing of patent document 3, the whole sheet | seat material will be loaded on a bottom plate, and all the weight of the sheet | seat material to load will be received by a bottom plate. For this reason, the weight fluctuation of the sheet material applied to the bottom plate becomes large between the large size sheet material and the small size sheet material. In the mechanism that feeds the sheet material, the pressure fluctuation between the sheet feeding roller and the sheet material also increases, and problems such as non-feed due to insufficient frictional force are likely to occur.

  The present invention eliminates the above-mentioned conventional problems, and even if the amount of sheet material stacked on the paper feed tray is set in a small state in advance, the interlocking operation of the two pressure plates provided on the end fence When the sheet material is set in a fully loaded state in the paper feed tray so that the pressure plate does not push the sheet material more than necessary, the sheet material leading edge is moved to the sheet material leading edge regulating member by pushing the two pressure plates. The sheet material can be moved without any gaps, and the sheet material can be moved smoothly, and the sheet material can be moved smoothly by pushing the sheet material to the paper feed position. An object is to perform stable paper feeding by pressing against a paper feeding roller.

  Furthermore, when the amount of sheet material to be set in the sheet feeding tray is reduced, the pressing force of the pressure plate provided on the end fence is reduced, and it is an object to suppress problems such as the sheet material being curved.

  According to another aspect of the present invention, there is provided a sheet feeding tray in which sheet materials are stacked and placed on a bottom plate that rotates about a fulcrum, and a side fence that regulates the position of the stacked sheet material in the width direction, and the stacked sheet materials The rear end position of the sheet material is regulated by a pressure plate that presses the upper side of the rear end of the sheet material and a pressure plate that presses the lower side of the rear end of the sheet material. A sheet feeding tray that lifts the sheet material by rotating the bottom plate and presses the uppermost sheet material to a sheet feeding roller provided in the image forming apparatus with a predetermined pressure and sequentially sends the sheet material; A plurality of pressure plates that pressurize the trailing edge of the sheet material loaded on the elastic plate is provided. The elastic member that presses one pressure plate is held by the end fence, and the elastic member that presses the other pressure plate is against the other pressure plate. Retained I am characterized in.

  The paper feed tray according to claim 2 is the paper feed tray according to claim 1, wherein a plurality of pressure plates provided on the end fence are rotatably held with respect to the end fence. And

  The sheet feeding tray according to claim 3 is the sheet feeding tray according to claim 1, wherein one of the pressure plates provided on the end fence has a rotation fulcrum half of the maximum height of sheet material stacking. It is provided at a height.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus that feeds a sheet material from a paper feed tray to an image forming unit and forms an image on the sheet material. The paper feed tray according to any one of the above is provided.

  In the paper feed tray according to claim 1 or 2, in the end fence that is provided in the paper feed tray and regulates the position of the rear end of the sheet material, the two pressure plates that are provided in the end fence and are rotatably held on the end fence, for example. One of them is subjected to pressure by an elastic member held by the end fence, and the other pressure plate is subjected to pressure by an elastic member held in a state of being sandwiched between two pressure plates. Therefore, one pressure plate receives pressure directly from the elastic member provided on the end fence, but the other pressure plate is held between the two pressure plates with the elastic member receiving pressure, The pressure applied to the other pressure plate varies depending on the rotational position of the pressure plate that receives pressure from the elastic member provided on the end fence. At this time, when the pressure plate that receives pressure from the elastic member held by the end fence is not in contact with the sheet material, and the other pressure plate is separated from the surface holding the elastic member, Since the pressing force of the elastic member that pressurizes one of the pressure plates is lowered, the pressing force by which the other pressing plate pressurizes the sheet material is also weakened. Therefore, the sheet of the other pressure plate is limited by limiting the range in which the pressure plate that receives pressure from the elastic member held by the end fence and the sheet material come into contact with the increase / decrease of the sheet material loaded on the paper feed tray. The pressure applied to the material varies. Therefore, the pressure applied to the trailing edge of the sheet material is adjusted according to the fluctuation of the sheet material loading amount, and the leading edge of the sheet material, which is related to the sheet material loading amount, is pushed out to the paper feeding position, so that the sheet material is fed smoothly. Stable feeding can be performed by pressing against the roller.

  In the sheet feeding tray according to claim 3, of the two pressure plates provided on the end fence, one rotation fulcrum of the pressure plates rotatably held by the end fence is set to a half of the maximum sheet material stacking height. By providing the height, the portion above the rotation fulcrum does not press the sheet material due to a decrease in the loading amount of the stacked sheet material. Thereby, the upper side of the pressure plate is pushed out to the sheet material side by the elastic force of the elastic member, and the lower side of the pressure plate is rotated in the opposite direction to the sheet material. As a result, the pressure plate lower part is separated from the sheet material, and the elastic member provided below the pressure plate is also separated from the sheet material. Therefore, the pressing force of the other pressure plate that presses the sheet material by the elastic member to the sheet material is become weak. Thereby, when the stacking amount of the sheet material set in the sheet feeding tray is reduced, it is possible to suppress problems such as the pressing force of the pressure plate provided on the end fence is lowered and the sheet material is curved.

  According to the paper feed tray of claim 1, the range in which the pressure plate that receives pressure from the elastic member held by the end fence and the sheet material is in contact with the increase or decrease of the sheet material stacked on the paper feed tray is limited. Since the pressure applied to the sheet material of the other pressure plate fluctuates, the pressure applied to the trailing edge of the sheet material is adjusted in accordance with the fluctuation of the sheet material loading amount, and the sheet is affected by the sheet material loading amount. Since the leading edge of the material is pushed out to the paper feeding position, the leading edge of the sheet material can be moved to the sheet material leading edge regulating member without any gap, and the sheet material can be smoothly fed to the paper feeding roller without the shortage of the pushing force of the sheet material. And stable feeding can be performed.

  According to the paper feed tray of the second aspect, in addition to the effect of the first aspect, the pressure plate held rotatably is a structure that rotates about the rotation fulcrum, thereby simplifying the structure of the end fence. .

  According to the sheet feeding tray of the third aspect, in addition to the effect of the first aspect, when the load amount of the sheet material set in the sheet feeding tray is reduced, the pressing force of the pressure plate provided on the end fence is reduced. Problems such as bending of the material can be suppressed.

  According to the image forming apparatus of the fourth aspect, the same effect as that of the first, second, or third aspect can be obtained.

It is a sectional side view which shows the paper feed tray of embodiment of this invention. FIG. 5 is a side cross-sectional view illustrating a state where a small amount of sheet material is placed on the sheet feeding tray according to the embodiment of the present invention. It is a perspective view of the end fence part in the paper feed tray of the embodiment of the present invention. It is a sectional side view of the end fence part in the paper feed tray of the embodiment of the present invention. It is an operation explanatory view when a sheet material is fully loaded in the paper feed tray of the embodiment of the present invention. It is an operation explanatory view when only half or less of the sheet material is placed on the paper feed tray of the embodiment of the present invention. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention.

  Next, embodiments of a paper feed tray and an image forming apparatus according to the present invention will be described with reference to the drawings. 1 is a side sectional view showing a sheet feeding tray according to an embodiment of the present invention, FIG. 2 is a side sectional view showing a state in which a small amount of sheet material is placed on the sheet feeding tray according to the embodiment, and FIG. FIG. 4 is a side sectional view of the end fence portion, FIG. 5 is an explanatory view of the operation when the sheet material is fully packed in the sheet feeding tray of the embodiment, and FIG. FIG. 7 is a schematic view of an image forming apparatus according to an embodiment of the present invention. FIG.

  In FIG. 7, reference numeral 100 denotes the image forming apparatus of the embodiment, 10 is the paper feed tray of the embodiment, 2 is a paper feed roller, 11 is a relay conveyance unit, 12 is a transfer unit, 13 is a fixing unit, and 14 is paper discharge. Reference numeral 15 denotes a paper discharge tray. A sheet material A such as transfer paper is stored in the sheet feed tray 10, and the sheet material A is taken out by the sheet feed roller 2 and conveyed to the transfer unit 12 via the relay conveyance unit 11. The transfer unit 12 includes a photosensitive drum or the like, and a toner image formed on the photosensitive drum is transferred to the sheet material A. The sheet material A to which the toner image has been transferred is conveyed to the fixing unit 13 where the toner image on the sheet material A is fixed. Then, the sheet material A sent from the fixing unit 13 is discharged from the paper discharge unit 14 onto the paper discharge tray 15. The transfer unit 12 and the fixing unit 13 are examples of “image forming unit”.

  As shown in FIGS. 1 and 2, the paper feed tray 10 has a housing 1 formed so as to be freely inserted into and removed from the main body of the image forming apparatus 100, and a bottom plate 3 having a rotation fulcrum 3 a on the housing 1. A side fence 4 erected at a position adjacent to the side portion of the bottom plate 3, a sheet material front end regulating member 5 located at the front end side of the housing 1, and an end fence 6 disposed at the rear portion of the housing 1. Yes.

  In addition, a pressure arm 31 having a rotation fulcrum 31a is disposed on the case 1 between the case 1 and the bottom plate 3. The pressure arm 31 is provided with a rotation fulcrum 31a by an elastic member (not shown). It is urged to turn to the bottom plate 3 side about the center. As a result, as shown in FIG. 2, the uppermost portion of the sheet material A placed on the bottom plate 3 is brought into pressure contact with the sheet feeding roller 2 with a predetermined pressure. 1 shows a state in which the paper feed tray 10 is pulled out from the image forming apparatus 100. In this state, the rotation of the pressure arm 31 is restricted by a mechanism (not shown).

  The end fence 6 includes two pressure plates 7 and 8. The pressure plate 7 is a U-shaped plate member that pressurizes the upper side of the sheet material A, and the pressure plate 7 that pressurizes the upper side has a rotation fulcrum 7a at the center of the stacking height H of the sheet material A. . Further, the pressure plate 8 is a plate member disposed in a U-shaped gap of the pressure plate 7 so as to press the lower side of the sheet material A. The pressure plate 8 that pressurizes the lower side is formed on the upper portion of the end fence 6. It has a pivot point 8a.

  Further, one end 7 b of the pressure plate 7 that pressurizes the upper side is in contact with the rear end upper portion of the sheet material A, and an elastic member 71 is disposed on the back side thereof to receive elastic pressure from the end fence 6. An elastic member 81 is disposed on the opposite end 7c on the conveyance direction side, and one end of the elastic member 81 is connected to a pressure plate 8 that pressurizes the lower side.

  As described above, the sheet feeding tray 10 includes the bottom plate 3 that is provided in the sheet feeding casing 1 and has the rotation fulcrum 3a and presses the uppermost portion of the stacked sheet material A to the sheet feeding roller 2 with a predetermined pressure, and the sheet material. A side fence 4 that regulates the width of A, a sheet material front regulating member 5 that regulates the position of the leading end of the sheet material A, and a rear end of the stacked sheet material A that regulates the rear end position of the sheet material A It is constituted by an end fence 6 provided with two pressure plates 7 and 8 that press the upper and lower portions of the part against the sheet material front end regulating member 5 with elastic pressures 71 and 81, respectively.

  Next, the operation will be described with reference to FIGS. As illustrated in FIG. 5, when the sheet material A is fully loaded, the pressure plate 7 that pressurizes the upper side is pushed into the end fence 6 side by the sheet material A. Further, the pressure plate 8 that pressurizes the lower side is also pushed into the end fence 6 side by the sheet material A. At this time, the pressure plate 7 that pressurizes the upper side is pressed toward the sheet material front end regulating member 5 by the one end 7b. The other end 7c of the pressure plate 7 moves toward the rear end of the sheet material A and pushes the elastic member 81 toward the sheet material A. Accordingly, the elastic pressure from the elastic member 81 received by the pressurizing plate 8 that pressurizes the lower portion increases, and the pressure applied to the sheet material A by the pressurizing plate 8 that pressurizes the lower portion increases. As a result, the sheet material A is pressurized toward the sheet material front end regulating member 5 and can be reliably fed by the sheet feeding roller 2.

  When the sheet material A is fed and the amount of the stacked sheet material A decreases, the pressure plate 7 that pressurizes the upper side is gradually pushed out by the elastic pressure of the end fence 6. As shown in FIG. 6, when the uppermost surface of the sheet material A becomes lower than the rotation fulcrum 7 a of the pressure plate 7 that pressurizes the upper side due to the decrease in the loading amount of the sheet material A, the upper pressure plate 7 is a position where one end 7 b is pushed out by the elastic pressure of the elastic member 71. At this time, since the one end 7c of the pressure plate 7 that pressurizes the upper side is located in a direction away from the sheet material A, the end of the elastic member 81 provided on the one end 7c is also moved away from the sheet material A. Therefore, the elastic pressure from the elastic member 81 received by the pressure plate 8 that pressurizes the lower portion is reduced, and the pressure applied to the pressure plate 8 that pressurizes the lower portion is reduced.

  With such a configuration, the sheet material A stacked on the bottom plate 3 is oriented in the direction of the sheet material front end regulating member 5 by the pressure plates 7 and 8 provided on the end fence 6 as the sheet material A is fed one by one. Even if the loading amount of the sheet material A to be stacked is changed, the leading end portion of the sheet material P does not move away from the sheet material leading edge regulating member 5, and the stacking amount of the sheet material A decreases. The sheet material A itself is fed into the main body of the image forming apparatus 100 without being bent by the pressure plate 8.

DESCRIPTION OF SYMBOLS 1 Housing 2 Feed roller 3 Bottom plate 3a Rotation fulcrum 4 Side fence 5 Sheet material front-end | tip regulating member 6 End fence 7 Pressurizing plate 8 which presses upwards Pressurizing plate 10 which presses downwards Feeding tray 71 Elastic member 81 Elastic member 100 Image Forming device A Sheet material

JP-A-9-67028 JP 2000-95356 A JP 2002-80128 A

Claims (4)

A side fence that stacks and mounts sheet materials on a bottom plate that rotates around a fulcrum and regulates the width direction of the stacked sheet materials, and an end fence that regulates the rear end of the stacked sheet materials The rear end position of the sheet material is regulated by a pressure plate that pressurizes the upper portion of the rear end portion of the sheet material and a pressure plate that pressurizes the lower portion of the rear end portion of the sheet material. In a paper feed tray that lifts and presses the uppermost sheet material to a paper feed roller provided in the image forming apparatus with a predetermined pressure and sequentially sends it out,
The end fence is provided with a plurality of pressure plates for pressing the rear end of the sheet material stacked in the paper feed tray, and the elastic member for pressing one of the pressure plates is held by the end fence and the elastic member for pressing the other pressure plate Is held against the other pressure plate.   2. The paper feed tray according to claim 1, wherein a plurality of pressure plates provided on the end fence are rotatably held with respect to the end fence.   2. The sheet feeding tray according to claim 1, wherein one of the plurality of pressure plates provided on the end fence is provided with a rotation fulcrum at a height that is half of a maximum sheet material stacking height. Paper tray to be used.   4. The image forming apparatus according to claim 1, wherein a sheet material is fed from a sheet feeding tray to an image forming unit to form an image on the sheet material. 5. An image forming apparatus comprising a paper feed tray.

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