JP2006089243A - Paper feeder and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise occurring from paper in feeding it and impact sound against a guide on the immediately upstream and downstream sides of a nip formed by the pressure contact of a paper feed roller on a separating member. <P>SOLUTION: A lift plate 23 on which the paper P is mounted is installed in the paper storage part 21 of a paper feed device 10. A fixed guide 24, the paper feed roller 32, and a separating roller 33 are installed on the downstream side of the lift plate 23 in the paper feeding direction and on the outside of the paper storage part 21. A movable guide 60 capable of taking a first attitude projected to a paper carrying route on the immediate upstream side and a second attitude projected to a paper carrying route on the immediate downstream side of the nip formed by the pressure contact of the paper feed roller 32 on the separating roller 33 is installed near the separating roller 33. The movable guide 60 prevents the rear end part of the paper P from being freely deformed by changing the attitude to the first attitude when the rear end of the paper P passes the immediate upstream side of the nip and to the second attitude when it passes the immediate downstream side of the nip. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper supply device such as a cut paper, which can be applied to an image forming apparatus represented by a copying machine or a printer. The present invention also relates to an image forming apparatus equipped with this paper supply device.

  The paper supply device is indispensable for an image forming apparatus represented by a copying machine or a printer. In the case where the paper is cut paper, the paper supply device often supplies the paper separately from the uppermost layer of the paper stacked in the paper storage unit. Such a paper supply device is used for a cassette type paper feeding unit, a manual paper feeding unit, a document feeding unit, and the like of an image forming apparatus.

  As means for feeding paper from the paper supply device to the outside, there are a roller supply method and a suction supply method, and the roller supply method is generally widely used. The roller supply system is composed of two sets of rollers provided upstream and downstream in the paper supply direction, and a pickup roller, which is an upstream roller, presses against the uppermost layer of the paper to place the paper on the downstream roller. The paper is delivered to a paper feed roller, and the paper is fed out of the paper supply device by the paper feed roller.

  Separation members such as separation rollers (rollers) and separation pads are used to separate the sheets fed by the sheet feeding roller one by one. These separating members are pressed against the sheet feeding roller from below, and stop feeding of the sheet on the separating member side when a plurality of sheets are about to be sent out.

  Here, in the supply means adopting the roller supply method, when the paper fed out by the paper feed roller leaves the paper storage section, the rear end of the paper is released and the paper is freely deformed due to the elasticity of the paper. May generate abnormal noise, or may collide violently with another guide member or the like provided immediately downstream of the paper storage unit, and generate a loud collision sound. In addition, when the trailing edge of the paper exits the nip formed by the pressure contact between the paper feed roller and the separating member, the paper itself generates an abnormal noise or violently collides with the surrounding guide members due to the elasticity of the paper. And may generate a loud collision sound.

As a means for solving the above problem, the rear end of the paper is generated from the paper by disposing the auxiliary guide at a place where it is likely to be freely deformed or collide. It is possible to reduce abnormal noise and collision noise. An example of a paper supply device using the means for arranging the auxiliary guide in this way can be seen in Patent Document 1.
JP-A-8-225186 (page 3-5, FIG. 1)

  In the paper feeding device (paper feeding device) described in Patent Document 1, an auxiliary guide member is disposed immediately downstream of the paper feeding cassette (paper storage unit), so that abnormal noise and collision noise generated from the paper at this location are arranged. Aims to reduce However, this method is applied to a supply means composed of a paper feed roller and a separation claw, and is composed of a pickup roller, a paper feed roller, and a separation member (separation roller, separation pad, etc.). Even if it is applied to the supply means, it is unlikely that sufficient effects will be obtained. This is because, when the supply means is composed of a pickup roller, a paper feed roller, and a separation member, as described above, the paper is formed when the paper feed roller and the separation member are pressed against each other when the paper is separated from the paper storage portion. This is because there is a possibility that an abnormal noise or a collision noise may be generated at two places when the nip exits the nip. That is, according to the method used in the paper feeding device described in Patent Document 1, it is not possible to reduce abnormal noise and collision noise when the paper comes out of the nip formed by the pressure contact between the paper feeding roller and the separating member. .

  The present invention has been made in view of the above points, and the paper is separated in two places, that is, when the paper leaves the paper storage portion and when the paper exits the nip formed by the pressure contact between the paper feed roller and the separating member. An object of the present invention is to provide a paper supply device capable of reducing abnormal noise generated from the sound and impact noise on the guide. It is another object of the present invention to provide an image forming apparatus having such a sheet supply device and an improved noise prevention effect.

  In order to solve the above-described problems, the present invention separates an overlapping sheet by stacking and accommodating a sheet, a sheet feeding roller for feeding the sheet from the sheet accommodating section, and the sheet feeding roller. In a paper supply apparatus comprising: a separating member that is provided on a downstream side of a paper supply direction of the paper storage unit and in the vicinity of the separation member, and a fixed guide that guides the paper fed from the paper storage unit in a predetermined direction A first posture protruding with respect to the sheet conveyance space immediately upstream of the nip formed by pressure-contact of the sheet feeding roller and the separation member, and a sheet conveyance space immediately downstream of the nip. The movable guide is provided with a movable guide that can take both the projecting second posture and the first guide when the trailing edge of the paper fed from the paper storage portion passes immediately upstream of the nip. of The energized, when passing through the immediately downstream side of the nip was decided to position change in said second position.

  Further, the movable guide has a bell crank shape in a vertical cross section parallel to the paper supply direction, and is rotatable about a shaft portion provided at a substantially central portion of the bell crank. The first paper contact portion is provided at the upstream end in the supply direction, the second paper contact portion is provided at the downstream end, and the first paper contact portion is provided when the movable guide is in the first posture. When in the second posture, the second paper contact portion projects into the paper transport space.

  The urging means for changing the position of the movable guide to the second position, and a conveying roller provided on the downstream side of the fixed guide for conveying a sheet, the movable guide being moved by the urging means, When the rear end of the paper fed out from the paper storage section passes immediately upstream of the nip, the paper always contacts the second paper contact of the movable guide. When the movable guide is changed in posture to the first posture against the urging force of the urging means by contacting the portion, and the trailing edge of the paper passes immediately downstream of the nip, The movable guide is changed to the second posture by pulling the paper downstream by the conveying roller and the urging means.

  Further, the movable guide has a width substantially the same as the maximum sheet width that can be accommodated in the sheet accommodating portion in a sheet width direction perpendicular to the sheet supply direction.

  In the present invention, the paper supply device is mounted on the image forming apparatus.

  According to the configuration of the present invention, the first posture that protrudes with respect to the sheet conveyance space immediately upstream of the nip formed by the pressure contact between the sheet feeding roller and the separation member, and the sheet conveyance immediately downstream of the nip. The movable guide includes a movable guide that can take both postures such as a second posture that protrudes with respect to the space, and the movable guide is provided when the trailing edge of the paper fed from the paper storage portion passes immediately upstream of the nip. Since the posture is changed to the second posture when passing the downstream side of the nip to the first posture, the paper is immediately upstream of the nip, that is, when it is separated from the paper storage portion, and immediately downstream of the nip. In other words, the paper can be brought into contact with the movable guide at two places, i.e., when exiting the nip. As a result, it is possible to prevent the paper from being freely deformed by its own elasticity at these two locations. Therefore, it is possible to reduce abnormal noise generated by the paper itself and loud collision sound caused by the paper violently colliding with a fixed guide provided in the vicinity of the separating member.

  Further, the movable guide has a bell crank shape in a vertical cross section parallel to the paper supply direction, and is rotatable about a shaft portion provided at a substantially central portion of the bell crank. A first paper contact portion is provided at the leading end on the upstream side in the direction, and a second paper contact portion is provided at the distal end on the downstream side. When the movable guide is in the first posture, the first paper contact portion is in the second position. Since the second paper abutting portion protrudes into the paper conveyance space when in this position, the paper feed roller and the separating member are formed in pressure contact with a simple configuration utilizing the shape of the bell crank. The movable guide can be easily protruded into two paper conveyance spaces on the upstream side and the downstream side of the nip. Therefore, the sheet can be easily brought into contact with the movable guide at two places, that is, when the sheet is separated from the sheet storage portion and when the sheet is removed from the nip.

  The movable guide includes an urging unit that changes the posture of the movable guide to the second posture, and a conveyance roller that is provided on the downstream side of the fixed guide and conveys the paper. When the trailing edge of the paper fed out from the paper storage portion passes immediately upstream of the nip, the paper comes into contact with the second paper contact portion of the movable guide, Since the movable guide is changed to the first posture against the urging force of the urging means, when the sheet abuts on the second sheet abutting portion protruding downstream of the nip, The force can be used to change the position of the movable guide to the first position. When the rear end of the sheet passes immediately downstream of the nip, the movable guide is changed to the second posture by the pulling of the sheet to the downstream side by the conveying roller and the urging means. Therefore, the force by which the sheet is pulled by the conveyance roller and the urging force by the urging unit can be used to change the posture of the movable guide to the second posture. In this way, the movable guide can be changed in posture by a simple structure using the propulsive force and biasing means of the paper, so it is necessary to prepare a special driving device for changing the posture of the movable guide. There is no. Therefore, it is possible to prevent noise generated from the driving device and to prevent the paper supply device from being increased in cost and size.

  Further, since the movable guide has substantially the same width as the maximum size of paper that can be accommodated in the paper container in the paper width direction perpendicular to the paper supply direction, In order to prevent free deformation due to the elasticity of the movable guide, the movable guide can be brought into contact with the paper. Thereby, the effect | action which reduces the noise generated from a paper and a collision sound is heightened, and it becomes possible to further improve the noise prevention effect of a paper supply apparatus.

  In the present invention, since the paper supply device is mounted on the image forming apparatus, when the paper leaves the paper storage portion and when the paper exits the nip formed by the pressure contact between the paper feed roller and the separation member. Thus, it is possible to obtain an image forming apparatus with an improved noise prevention effect that can reduce abnormal noise and collision noise generated from the paper.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an outline of the structure of an image forming apparatus using a paper supply apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper supply device 10 is disposed below the inside of the main body 2 of the printer 1. The paper supply device 10 is provided with a paper cassette 20. The paper P is stacked and accommodated in the paper cassette 20. Then, the paper P is sent out toward the upper right of the paper cassette 20 in FIG. The paper cassette 20 can be pulled out horizontally from the front side of the main body 2, that is, from the right side in FIG. Details of the paper supply device 10 will be described later.

  A paper feed path 3, a registration roller 4, an image forming unit 40, and a transfer unit 50 are disposed downstream of the paper supply device 10 in the paper supply direction. The image forming unit 40 is provided with a photosensitive drum 41 as an image carrier at the center thereof. An optical unit 5 is provided above the image forming unit 40, and laser light L is emitted from the optical unit 5 toward the photosensitive drum 41. A one-dot chain line in the figure indicates the laser beam L. The transfer unit 50 includes a transfer roller 51 as a transfer member. The transfer roller 51 is pressed against the photosensitive drum 41 from below to form a transfer nip portion for transferring the toner image onto the paper P.

  A fixing unit 6, a discharge paper transport path 7, and a paper discharge unit 8 are disposed downstream of the image forming unit 40 and the transfer unit 50 in the paper transport direction. The paper discharge unit 8 is provided on the upper surface of the main body 2 at a position where the printed paper P can be taken out from the outside.

  A double-sided printing paper conveyance path 9 is disposed below the fixing unit 6 and the transfer unit 50 and between the paper supply device 10. The double-sided printing paper conveyance path 9 branches from the middle of the discharge paper conveyance path 7 and joins the paper supply paper conveyance path 3 immediately downstream of the supply means 30.

  The printer 1 having the above configuration performs a printing operation as follows.

  The paper P before printing is stored in a stacked state in the paper cassette 20 of the paper supply device 10, and is fed one by one by the supply means 30 therefrom. The fed paper P reaches the registration roller 4 through the paper feeding paper conveyance path 3. The registration roller 4 corrects the oblique feeding of the paper P, measures the timing with the toner image formed by the image forming unit 40, and sends the paper P to the transfer unit 50.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and laser light L controlled by the optical unit 5 is irradiated based on the image data. As a result, an electrostatic latent image of the original image is formed on the photosensitive drum 41 in the image forming unit 40, and a toner image is formed on the photosensitive drum 41 from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 4 at a transfer nip portion formed by press contact between the photosensitive drum 41 and the transfer roller 51 of the transfer portion 50.

  Thereafter, the paper P carrying the unfixed toner image is sent to the fixing unit 6 and the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 6 is sent upward through the discharge paper conveyance path 7 and is discharged to the paper discharge unit 8 provided on the upper surface of the main body 2.

  When performing duplex printing, the transport direction of the paper P discharged from the fixing unit 6 is switched immediately before being discharged to the paper discharge unit 8 through the discharge paper transport path 7. Then, the paper P is sent to the double-sided printing paper conveyance path 9, merged with the paper feeding paper conveyance path 3 immediately downstream of the supply means 30, and sent again to the transfer unit 50.

  Next, the detailed configuration of the paper supply apparatus 10 according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 3 in addition to FIG. FIG. 2 is a partially enlarged schematic vertical section showing the periphery of the paper supply device, and FIG. 3 is a schematic perspective view of the same.

  As shown in FIGS. 1 to 3, the paper supply device 10 includes a paper cassette 20. The paper cassette 20 is provided with a paper storage portion 21 at most of the locations from the upstream end to the downstream portion in the paper supply direction. The paper storage unit 21 is configured by a flat box whose upper surface is open. The paper P is stacked and stored from above the paper storage unit 21. The paper cassette 20 can be slid horizontally with respect to the main body 2 by engaging a horizontal protrusion 22 (see FIG. 3) provided on the side surface thereof with a rail (not shown) inside the main body 2 of the printer 1. Can be pulled out horizontally from the front side, that is, from the right side in FIG.

  A lift plate 23 is provided on the inner bottom surface of the paper storage unit 21. Paper P such as cut paper before printing is placed on the lift plate 23. The upstream end of the lift plate 23 in the paper supply direction is supported on the inner bottom surface of the paper storage unit 21 (see FIG. 1), and can rotate about the support shaft and the downstream end as a free end. A drive unit (not shown) is provided below the lift plate 23 and between the inner bottom surface of the sheet storage unit 21. The downstream portion of the lift plate 23 is lifted upward by the action of the driving means, and is displaced to the paper supply position shown in FIGS. The paper P on the lift plate 23 is separated one by one by a supply means 30 provided in the vicinity of the downstream end of the lift plate 23 and sent out of the paper cassette 20.

  As shown in FIG. 2, in the vicinity of the downstream end of the lift plate 23, a supply unit 30 that sends out the paper P from the paper cassette 20 is disposed. The supply unit 30 includes a pickup roller 31, a paper feed roller 32, and a separation roller 33. The supply means 30 is disposed at a substantially central portion in the paper width direction that is perpendicular to the paper supply direction.

  The pickup roller 31 is provided above the downstream portion of the lift plate 23. From the lower side of the pickup roller 31, the downstream portion of the paper P stacked on the paper cassette 20 is pushed up by the lift plate 23, and one of the uppermost layers of the paper P is in pressure contact. Then, the paper P is delivered to the paper feed roller 32 by the pickup roller 31 and is sent out of the paper cassette 20 by the paper feed roller 32.

  The paper feed roller 32 is connected to a motor (not shown). The pickup roller 31 and the paper feed roller 32 are connected to each other through a driven gear and an intermediate gear which are not shown. Thus, when the paper feed roller 32 is rotated by the motor, the pickup roller 31 is also rotated in the same direction as the paper feed roller 32.

  The separation roller 33 is provided below the paper feed roller 32 in FIG. 2 and is in pressure contact with the paper feed roller 32. The paper P is inserted through a nip formed by the separation roller 33 and the paper feed roller 32 being pressed against each other. A motor is not connected to the separation roller 33. Since the separation roller 33 is in pressure contact with the paper feed roller 32, the separation roller 33 is rotated according to the rotation of the paper feed roller 32.

  The separation roller 33 is provided with a torque limiter (not shown) on its shaft portion 33a. When the sheet P does not exist in the nip formed by the pressure contact between the separation roller 33 and the paper feed roller 32 or when only one sheet P enters, the separation roller 33 is subjected to a torque greater than the torque set by the torque limiter. The separation roller 33 rotates in the direction of feeding the paper P according to the paper feed roller 32. However, when a plurality of sheets P enter the nip, the torque applied to the separation roller 33 does not exceed the set torque of the torque limiter, and the separation roller 33 stops rotating. As a result, the overlapped lower side paper P is not sent out, so that it is possible to prevent the problem of double feeding in which the paper P is overlapped and sent.

  As shown in FIGS. 2 and 3, a fixed guide 24 is provided on the outside of the sheet storage portion 21 immediately downstream of the lift plate 23. The fixed guide 24 has a shape curved upward from the vicinity of the downstream end of the lift plate 23 in order to guide the paper P on the lift plate 23 in the direction of the paper feed path 3 for the paper feed. 20 is fixed to the downstream portion. Since the lift plate 23 rotates about the support shaft at the upstream end, a gap is left between the downstream end of the lift plate 23 and the upstream end of the fixed guide 24 as shown in FIG. The separation roller 33 of the supply means 30 is disposed so as to be embedded in the center portion in the sheet width direction of the fixed guide 24 so that a part of the surface of the separation roller 33 protrudes toward the sheet conveyance space on the surface of the fixed guide 24. .

  As shown in FIGS. 2 and 3, a movable guide 60 is provided in the vicinity of the separation roller 33 in the center of the fixed guide 24 in the sheet width direction. As shown in FIG. 3, the movable guide 60 has a U shape in which the shape viewed from the paper supply direction, that is, the shape viewed from the rear of the printer 1, sandwiches the separation roller 33 in the center in the paper width direction. ing. Further, as shown in FIG. 2, the movable guide 60 has a vertical cross-sectional shape parallel to the paper supply direction, that is, a shape viewed from the side of the printer 1 has a bell crank shape. A portion 60a is provided. The movable guide 60 is supported by inserting a shaft portion 60a into a support portion (not shown) of the fixed guide 24, and can be rotated in a vertical plane around the shaft portion 60a. The movable guide 60 includes a first sheet contact portion 60b at the upstream end of the bell crank and a second sheet contact portion 60c at the downstream end.

  As shown in FIG. 2, the shaft portion 60 a of the movable guide 60 is close to the shaft portion 33 a of the separation roller 33 when viewed from the paper width direction. Accordingly, the movable guide 60 causes the first sheet contact portion 60b to protrude with respect to the sheet conveyance space immediately upstream of the nip formed by the contact between the sheet feeding roller 32 and the separation roller 33 due to the rotating operation. Both the first posture and the second posture in which the second paper contact portion 60c protrudes from the paper conveyance space immediately downstream of the nip can be taken. FIG. 2 illustrates a state in which the movable guide 60 is in the second posture. When the movable guide 60 is rotated clockwise from here, the posture is changed to the first posture.

  As shown in FIG. 2, a spring 61, which is a biasing means, is attached between the movable guide 60 and the fixed guide 24 immediately above the shaft portion 60 a. The spring 61 is constituted by a compression coil spring, and in FIG. 2, is urged to rotate the movable guide 60 in the counterclockwise direction to change the posture to the second posture. However, the movable guide 60 does not rotate counterclockwise beyond the position shown in FIG. 2 due to the action of a stopper (not shown). The spring 61 has a resilience that does not interfere with the rotation of the movable guide 60 in the clockwise direction in FIG. 2 when the sheet P abuts against the second sheet abutting portion 60 c of the movable guide 60. Thus, the movable guide 60 always maintains the second posture by the action of the spring 61.

  The spring 61 is not limited to a compression coil spring, and other elastic members such as a leaf spring, rubber, sponge, etc. may be used. Further, instead of the spring 61, a repulsive force by a magnet or an attractive force may be used to urge the movable guide 60 to change its posture to the second posture.

  As shown in FIGS. 1 and 2, a conveyance roller 70 is provided on the downstream side of the fixed guide 24 and the movable guide 60 and on the sheet conveyance path 3. The transport roller 70 receives the paper P sent out from the paper cassette 20 by the supply unit 30 and transports the paper P to the registration roller 4 through the paper feed paper transport path 3.

  Next, the sheet P supply operation by the sheet supply apparatus 10 will be described with reference to FIGS. 4 and 5 in addition to FIGS. 2 and 3. 4 is a partially enlarged schematic vertical cross-sectional view showing the periphery of the paper supply apparatus similar to FIG. 2, showing the state where the movable guide is in the first posture, and FIG. 5 is a schematic perspective view similar to FIG. Thus, the movable guide is in the first posture.

  As shown in FIGS. 2 and 3, in the printer 1, before the paper P is sent out from the paper cassette 20 of the paper supply device 10 by the supply means 30, the movable guide 60 is moved by the action of a spring 61 as an urging means. 2 posture. Therefore, the second paper contact portion 60c of the movable guide 60 protrudes into the paper transport space immediately downstream of the nip formed by the pressure contact between the paper feed roller 32 and the separation roller 33. The first paper contact portion 60b of the movable guide 60 is retracted downward from the paper transport space.

  Here, when the printer 1 receives a print command from an external computer, the supply operation of the paper P by the supply unit 30 is started. The paper P is fed from the lift plate 23 to the downstream side by the pickup roller 31 and enters a nip formed by the pressure contact between the paper feed roller 32 and the separation roller 33.

  When the leading edge of the paper P passes through the nip and reaches the paper conveyance space immediately downstream of the nip, it contacts the second paper contact portion 60 c of the movable guide 60. Accordingly, the movable guide 60 is changed in posture to the first posture shown in FIGS. 4 and 5 against the urging force of the spring 61. Therefore, the first sheet contact portion 60b of the movable guide 60 protrudes in the sheet conveyance space immediately upstream of the nip and in the gap between the downstream end of the lift plate 23 and the upstream end of the fixed guide 24. To do. The second paper contact portion 60c of the movable guide 60 retreats outside the paper transport space.

  Thereafter, the feeding of the paper P proceeds, and when the rear end of the paper P passes immediately upstream of the nip, that is, when it is separated from the paper container 21, the movable guide 60 continues to be the first shown in FIGS. 1 posture. As a result, the first paper contact portion 60b of the movable guide 60 protrudes into the gap between the downstream end of the lift plate 23 and the upstream end of the fixed guide 24 so that the paper P does not deform freely due to its elasticity. Assist with transport.

  When the feeding of the paper P further proceeds, the leading edge of the paper P is transferred to the transport roller 70 on the downstream side of the fixed guide 24, and the paper transport by the transport roller 70 is started. As a result, the paper P is pulled downstream from the nip. When the trailing edge of the sheet P passes immediately downstream of the nip, the movable guide 60 is pulled by the sheet P being pulled downstream by the conveying roller 70 and the urging force of the spring 61 acting. The posture is changed to the second posture shown in FIGS. Therefore, the second paper contact portion 60c of the movable guide 60 projects into the paper transport space immediately downstream of the nip. As a result, when the trailing edge of the paper P passes immediately downstream of the nip, that is, when it exits the nip, the movable guide 60 is free from the elasticity of the paper P by the elasticity of the second paper contact portion 60c. Assists conveyance so as not to deform. The first paper contact portion 60b of the movable guide 60 is retracted downward from the paper transport space.

  In this way, the first posture that protrudes with respect to the sheet conveyance space immediately upstream of the nip formed by the pressure contact between the paper feed roller 32 and the separation roller 33 that is a separation member, and the immediately downstream side of the nip. The movable guide 60 has a movable posture 60 that can take both the second posture and the second posture protruding with respect to the paper conveyance space. Since the posture is changed to the first posture when passing the upstream side and to the second posture when passing immediately downstream of the nip, the paper P is immediately upstream of the nip, that is, the lift plate 23 of the paper storage unit 21. The sheet P can be brought into contact with the movable guide 60 at two positions, that is, when it is separated from the nip, and immediately downstream of the nip, that is, when it exits the nip. As a result, the paper P can be prevented from being freely deformed by its own elasticity at these two locations. Therefore, it is possible to reduce noise generated by the sheet itself and loud collision noise caused by the sheet P violently colliding with the fixed guide 24 provided in the vicinity of the separation roller 33.

  The movable guide 60 has a bell crank shape in a vertical cross section parallel to the paper supply direction, and is rotatable about a shaft portion 60a provided at a substantially central portion of the bell crank. A first paper contact portion 60b is provided at the upstream end in the paper supply direction, and a second paper contact portion 60c is provided at the downstream end. When the movable guide 60 is in the first position, the first paper contact portion 60b is provided. When the portion 60b is in the second posture, the second paper contact portion 60c protrudes into the paper conveyance space, so that the paper feed roller 32 and the separation roller 33 are separated by a simple configuration utilizing the shape of the bell crank. The movable guide 60 can be easily protruded into two paper conveyance spaces on the upstream side and the downstream side of the nip formed by pressure contact. Therefore, the paper P can be easily brought into contact with the movable guide 60 at two places, that is, when the paper P is separated from the paper storage portion 21 and when the paper P is pulled out of the nip.

  Further, the movable guide 60 includes a spring 61 that is an urging unit that changes the posture of the movable guide 60 to the second posture, and a conveyance roller 70 that is provided on the downstream side of the fixed guide 24 and conveys the paper P. The spring 61 always holds the second posture, and when the rear end of the paper P sent out from the paper storage portion 21 passes immediately upstream of the nip, the paper P is moved to the second position of the movable guide 60. Since the movable guide 60 is changed to the first posture against the urging force of the spring 61 by abutting against the second paper abutting portion 60c, the paper P protrudes downstream of the nip. The force at the time of contact with the sheet contact portion 60c can be used to change the posture of the movable guide 60 to the first posture. When the trailing edge of the paper P passes immediately downstream of the nip, the movable guide 60 is changed to the second posture by the pulling of the paper downstream by the conveying roller 70 and the spring 61. Therefore, the force by which the paper P is pulled by the transport roller 70 and the urging force by the spring 61 can be used to change the posture of the movable guide 60 to the second posture. In this way, the movable guide 60 can be changed in posture by a simple structure using the propulsive force of the paper P and the spring 61, and therefore a special driving device for changing the posture of the movable guide 60 is prepared. There is no need to do. Therefore, it is possible to prevent noise generated from the driving device and to prevent the paper supply device 10 from being increased in cost and size.

  In the present invention, since the paper supply device 10 is mounted on the printer 1 as an image forming apparatus, the paper P is formed when the paper feed roller 32 and the separation member 33 are pressed against each other when the paper P is separated from the paper storage portion 21. The printer 1 with an improved noise prevention effect can be obtained, which can reduce abnormal noise and collision noise generated from the paper P at two points when the nip is removed.

  Next, a detailed configuration of the paper supply apparatus 10 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic perspective view showing the periphery of the paper supply device. Since the basic configuration of this embodiment is the same as that of the first embodiment shown in FIGS. 1 to 5, the same components as those of the first embodiment are denoted by the same reference numerals as before, The description will be omitted.

  In the second embodiment, as shown in FIG. 6, the movable guide 60 provided in the paper cassette 20 has a width substantially the same as the maximum size paper width that can be accommodated in the paper accommodating portion 21. . The movable guide 60 is provided at a location of the fixed guide 24 found in the first embodiment, and no other guide member exists at this location. The movable guide 60 changes the posture and assists the conveyance so that the paper P is not freely deformed due to its elasticity, and feeds the paper P on the lift plate 23 like the fixed guide 24 of the first embodiment. It also plays a role of guiding in the direction of the paper transport path 3.

  In this way, the movable guide 60 has substantially the same width as the maximum sheet width that can be accommodated in the sheet accommodating portion 21 in the sheet width direction perpendicular to the sheet supply direction. The movable guide 60 can be brought into contact with the paper P in order to prevent free deformation due to the elasticity of the paper itself. Thereby, the effect | action which reduces the abnormal sound and collision sound which generate | occur | produce from the paper P is heightened, and it becomes possible to further improve the noise prevention effect of the printer 1.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in a paper supply device that feeds a paper from a paper storage unit by a supply unit that includes a paper supply roller and a separation member that separates the overlapped paper by pressing against the paper supply roller.

1 is a left side view of a schematic vertical section of a printer equipped with a paper supply device according to an embodiment of the present invention. FIG. 3 is a partially enlarged schematic vertical cross-sectional view showing the periphery of the paper supply device according to the first embodiment of the present invention. FIG. 3 is a perspective view of the periphery of the paper supply device shown in FIG. 2. FIG. 3 is a model vertical cross-sectional partial enlarged view showing the periphery of the paper supply apparatus similar to FIG. 2 and shows a state where the movable guide is in the first posture. FIG. 4 is a perspective view of the periphery of the paper supply apparatus similar to FIG. 3 and shows a state where the movable guide is in the first posture. It is a perspective view which shows the paper supply apparatus periphery which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1 Printer (image forming device)
2 Main body 3 Paper feeding path 10 Paper feeding device 20 Paper cassette 21 Paper storage part 23 Lift plate 24 Fixed guide 30 Supply means 31 Pickup roller 32 Paper feed roller 33 Separating roller 60 Movable guide 61 Spring (biasing means)
70 Transport roller

Claims (5)

A paper storage unit for stacking and storing paper, a paper feed roller that feeds paper from the paper storage unit, a separation member that presses against the paper supply roller and separates overlapping paper, and a paper supply direction of the paper storage unit In the paper supply apparatus provided with a fixed guide provided on the downstream side and in the vicinity of the separation member and guides the paper fed from the paper storage unit in a predetermined direction,
A first posture protruding from the sheet conveyance space immediately upstream of the nip formed by pressure-contact of the sheet feeding roller and the separation member, and a protrusion from the sheet conveyance space immediately downstream of the nip. And a movable guide that can take both postures of the second posture, the movable guide, and the first guide when the trailing edge of the paper fed from the paper storage portion passes immediately upstream of the nip. The sheet supply device is characterized in that the posture is changed to the second posture when the posture passes immediately downstream of the nip.   The movable guide has a bell crank shape in a vertical cross section parallel to the paper supply direction, and is rotatable about a shaft portion provided at a substantially central portion of the bell crank. A first paper contact portion is provided at the upstream tip, and a second paper contact portion is provided at the downstream tip. When the movable guide is in the first posture, the first paper contact portion is 2. The sheet feeding device according to claim 1, wherein the second sheet abutting portion protrudes into the sheet conveyance space when in the posture of 2.   An urging unit that changes the posture of the movable guide to the second posture, and a conveyance roller that is provided on the downstream side of the fixed guide and conveys a sheet, and the movable guide is constantly moved by the urging unit. The second posture is maintained, and when the rear end of the paper fed out from the paper storage portion passes immediately upstream of the nip, the paper is brought into contact with the second paper contact portion of the movable guide. By contact, the movable guide is changed to the first posture against the urging force of the urging means, and when the rear end of the sheet passes immediately downstream of the nip, the conveyance roller The sheet feeding device according to claim 1 or 2, wherein the movable guide is changed to a second position by the sheet being pulled downstream by the biasing means and the biasing means.   4. The movable guide according to claim 1, wherein the movable guide has a width substantially equal to a maximum sheet width that can be accommodated in the sheet accommodating portion in a sheet width direction perpendicular to the sheet supply direction. The paper supply device according to any one of claims   An image forming apparatus comprising the paper supply device according to claim 1.

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