JP3872276B2 - Paper feeding device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeding device that separates recording paper stored in a paper feeding cassette by a copying machine, a printer, a facsimile machine, and the like and conveys the recording paper to an image forming unit, and an image forming apparatus using the paper feeding device.
[0002]
[Prior art]
  When an image is formed on a recording sheet by a copying machine or the like, the recording sheet stored in a paper feed cassette is separated and conveyed to an image forming unit to transfer the image. When supplying the recording paper from the paper feed cassette to the image forming unit, the recording paper is separated one by one by the paper feeding device in order to eliminate problems such as printing failure and device stoppage due to paper jam. Need to be transported to. As one of the mechanisms for separating the recording sheets one by one, an FRR paper feeding method is adopted as shown in, for example, Japanese Patent Laid-Open Nos. 9-202477 and 11-59941. This FRR paper feeding method is, for example,As shown in FIG.A feeding roller 31 provided in the upper part of the paper feed cassette 28 that stores the recording paper 32, a paper feeding roller 33 provided on the downstream side of the feeding roller 31 in the conveyance direction of the recording paper 32, and a conveyance path of the recording paper 32 And a reverse rotation roller 34 provided opposite to the paper feed roller 33. The paper feed cassette 28 has a push-up arm 38 that is rotatable inside, and pushes up the recording paper 32 stored by the push-up arm 38. The recording sheet 32 on the uppermost side of the pushed-up recording sheet 32 is positioned at a fixed position. The attracting roller 31 contacts and separates from the uppermost recording sheet 32 of the recording sheet 32 lifted by the push-up arm 38 by the operation of the pickup solenoid 70. A paper feed motor 40 is attached to the rotation shaft of the paper feed roller 33 via a paper feed clutch 39. The feed roller 33 and the attracting roller 31 are connected by a relay gear group 71, and the attracting roller 31 is also rotated by the rotation of the feed roller 33. The reverse rotation roller 34 has a built-in torque limiter 43 and is brought into contact with and separated from the paper feed roller 33 by the operation of the pressure solenoid 72.
[0003]
When transporting the recording paper 32 stored in the paper feed cassette 28 to the image forming unit, the rotation of the paper feed motor 40 is started and simultaneously the pressure solenoid 72 is turned on to bring the reverse roller 31 into contact with the paper feed roller 33. . Thereafter, the pickup solenoid 70 is turned on to bring the attracting roller 31 into contact with the upper surface of the recording paper 32 stored in the paper feed cassette 28. When the paper feed clutch 39 is turned on in this state, the paper feed roller 33 rotates, and the incoming roller 31 rotates via the relay gear group 71 to pick up the uppermost recording paper 32 in the paper feed cassette 28. The paper is fed between the paper feed roller 33 and the reverse rotation roller 34. The paper feed roller 33 conveys the fed recording paper 32. When the recording paper 32 is conveyed by the paper feed roller 33, the reverse rotation roller 34 is rotated with the paper feed roller 33 due to the frictional force with the paper feed roller 33 exceeding the torque of the built-in torque limiter 43. At this time, when two or more recording sheets 32 are fed, the reverse rotation roller 34 rotates in a direction to return the lower recording sheet 32 by the action of the torque limiter 43. When the recording paper 32 conveyed by the paper feed roller 33 is detected by the reflection type paper detection sensor 42, the pickup solenoid 70 is turned off to lift the attracting roller 31 away from the recording paper 32 and carry by the paper feed roller 33. The load on the recording paper 32 is reduced. When the recording sheet 32 is conveyed to the registration roller 73, the sheet feeding clutch 39 is turned off to stop the rotation of the sheet feeding motor 40, the pressure solenoid 72 is turned off, and the reverse rotation roller 34 is separated from the sheet feeding roller 33.
[0004]
  In this way, the reverse rotation roller is brought into contact with the paper feed roller only when the recording paper is conveyed, and when the recording paper is not conveyed, the reverse rotation roller is kept away from the paper feed roller.Long life of reverse rollerIn addition, when a recording paper jam occurs, the recording paper on which the jam has occurred can be easily removed.
[0005]
[Problems to be solved by the invention]
The conventional paper feeding method requires two solenoids, a pickup solenoid that contacts and separates the attracting roller to the recording paper, and a pressure solenoid that contacts the reverse rotation roller to the paper feeding roller. Therefore, it is difficult to reduce the cost because a control device that controls and turns on and off while taking the above timing is required.
[0006]
SUMMARY OF THE INVENTION The present invention improves the above disadvantages, and performs a low cost paper feeding device and an image forming apparatus using the same by performing contact and separation of the incoming roller with respect to the recording paper and contact and separation of the reverse rotation roller and the paper feeding roller with one drive source. Is intended to provide.
[0007]
[Means for Solving the Problems]
  The paper feeding device according to the present invention feeds the recording paper sandwiched between the feeding roller for moving the stacked recording paper, the paper feeding roller provided on the downstream side of the feeding path of the recording paper from the feeding roller, and the feeding path of the recording paper. Opposite the paper rollerA reversing roller provided; and the feeding roller and the paper feeding roller are held at both ends of a pivoting arm having a pivoting fulcrum at the center, and the feeding roller contacts the recording paper and the paper feeding roller Is a sheet feeding device that switches contact of the reversing roller with rotation of the rotating arm, wherein the attracting roller contacts the recording sheet in the vicinity of both sides of the reversing roller at the nip portion of the sheet feeding roller and the reversing roller. When the recording paper is moved, the moving recording paper is lifted from the surface of the reverse rotation roller, the contact between the drawing roller and the recording paper is released, and the paper feed roller contacts the reverse rotation roller. And a separating unit that retreats from the recording paper conveyance path and releases the recording paper.
[0008]
  AboveIt is preferable that the contact of the drawing roller with respect to the recording sheet is canceled by a sheet detection signal from a sheet detection sensor provided on the downstream side of the sheet feeding roller, and the sheet feeding roller is brought into contact with the reverse rotation roller.
[0009]
  Also,AboveSeparation of the rotating arm, the initial position where the attracting roller does not contact the recording paper and the feeding roller does not contact the reversing roller, the attracting position where the attracting roller contacts the recording paper, and the feeding roller contacts the reversing roller -It is desirable to position at the paper feed position.
[0011]
An image forming apparatus according to the present invention includes the paper feeding device.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The digital copying machine of the present invention has a copying machine body, an automatic document feeder and an automatic sorting device. The copying machine main body includes a scanner unit that reads a document, and a printer unit that includes a writing unit, an engine unit, and a paper feeding unit. The engine unit includes an image forming unit, a primary transfer unit, a secondary transfer unit, and a fixing unit. The image forming unit forms an electrostatic latent image on the photosensitive member charged by the charging charger with a laser beam emitted from the writing unit, and visualizes the formed electrostatic latent image with a color developing unit to form a toner image. . The primary transfer unit primarily transfers the toner image formed on the photosensitive member to the intermediate transfer belt and superimposes the toner images of the respective colors. The secondary transfer unit secondarily transfers the toner image transferred to the intermediate transfer belt onto the recording paper. The fixing unit fixes the toner image transferred to the recording paper with heat and pressure. The paper feed unit has a plurality of paper feed cassettes and sends recording paper to the secondary transfer unit.
[0013]
The paper feed cassette of the paper feed unit sandwiches a recording roller transport path, and a feeding roller provided at the top of the paper feeding cassette, a paper feeding roller provided downstream of the suction roller in the recording paper transport direction. The reversing roller provided in opposition to the paper feed roller, the pivot arm at the center, and the pivot arm and pivot arm that rotatably hold the incoming roller and paper feed roller at both ends. It has a drive unit such as a solenoid and a servo motor.
[0014]
When the recording paper is not transported by this paper cassette, the rotating arm is held at the initial position, the attracting roller is separated from the recording paper stored in the paper cassette, and the paper feeding roller is separated from the reverse roller. Leave it in a state. When the image forming process is started in the engine unit of the digital copying machine in this state, the driving unit rotates the rotating arm around the rotating fulcrum, and the drawing roller is placed on the uppermost surface of the recording paper stored in the paper feeding cassette. , And the pickup roller is rotated to pick up the uppermost recording paper in the paper feed cassette and send it to the nip portion between the paper feed roller and the reverse rotation roller. When the leading end of the fed recording paper is detected by a paper detection sensor provided on the downstream side of the paper feeding roller, the drive unit rotates the rotating arm in the reverse direction, and the feeding roller is separated from the recording paper to feed the paper feeding roller. Is brought into contact with the reverse rotation roller, and the recording paper is sandwiched and separated and conveyed by the paper supply roller and the reverse rotation roller. When the recording sheet conveyed by the sheet feeding roller passes the position of the sheet feeding roller and the trailing edge of the conveyed recording sheet passes the position of the sheet detection sensor, the drive unit rotates the rotating arm. Returning to the initial position, the paper feed roller is separated from the reverse rotation roller 34, and the calling arm is separated from the recording paper stored in the paper feed cassette.
[0015]
【Example】
[Embodiment 1] FIG. 1 is a block diagram showing the construction of an embodiment of the present invention. As shown in the figure, the digital copying machine 1 has a copying machine main body 2, an automatic document feeder (hereinafter referred to as ADF) 3, and an automatic sorting device 4. The copying machine main body 2 includes a scanner unit 5 that reads a document, and a printer unit 9 that includes a writing unit 6, an engine unit 7, and a paper feeding unit 8. The ADF 3 sends the document to be read to the scanner unit 5 and collects the document read by the scanner unit 5. The scanner unit 5 includes a carriage 10 having a light source, a plurality of mirrors, a lens 11, and a CCD 12, and scans and reads a document sent by the ADF 3. The writing unit 6 includes a laser light source, a polygon mirror, and the like, and emits a laser beam 13 including image information to the engine unit 7. As shown in the configuration diagram of FIG. 2, the engine unit 7 includes an image forming unit 14, a primary transfer unit 15, a secondary transfer unit 16, and a fixing unit 17. The image forming unit 14 includes a charging charger 19 and a color developing unit 20 and a drum cleaning unit 21 made of cyan (C), magenta (M), yellow (Y), and black (K) disposed around the photoconductor 18. The electrostatic latent image is formed on the photosensitive member 18 charged by the charging charger 19 by the laser beam 13 emitted from the writing unit 6, and the formed electrostatic latent image is visualized by the color developing unit 20 to be a toner image. Form. The primary transfer unit 15 includes an intermediate transfer belt 22, a primary transfer unit 23, a tension roller 24, a secondary transfer roller 25, a cleaning unit 26, and a reference position sensor 27. The primary transfer unit 15 intermediates a toner image formed on the photoconductor 18. Primary transfer is performed on the transfer belt 22 to superimpose the toner images of the respective colors. The intermediate transfer belt 22 is separated from the surface of the photosensitive member 18 by a contact / separation mechanism except when the toner image on the photosensitive member 18 is primarily transferred, and is pressed against the surface of the photosensitive member 18 only when the image is primarily transferred to the intermediate transfer belt 22. Is done. The secondary transfer unit 16 secondarily transfers the toner image transferred to the intermediate transfer belt 22 onto a recording sheet. The fixing unit 17 fixes the toner image transferred to the recording paper with heat and pressure. The paper feed unit 8 has a plurality of paper feed cassettes 28 a to 28 c and a manual feed tray 29, and sends recording paper to the secondary transfer unit 16. The automatic sorting device 4 has a plurality of sorting bins 30a to 30n, and sorts and discharges the recording sheets on which images are formed.
[0016]
When the image forming cycle of the document read by the scanner unit 5 in the digital copying machine 1 is started, if the image to be formed is one color, a toner image is formed on the photoconductor 18 by the image data of the read document. The toner image is primarily transferred to the intermediate transfer belt 22. The secondary transfer unit 16 secondarily transfers the toner image onto a recording sheet fed in accordance with the tip of the toner image transferred to the intermediate transfer belt 22. The recording sheet onto which the toner image has been transferred is sent to the fixing unit 17 and fixed by heating and pressing. The recording paper on which the toner image is fixed is discharged to the automatic sorting device 4. Further, the toner remaining on the intermediate transfer belt 22 is collected by the cleaning unit 26.
[0017]
If the image to be formed has two or more colors, the scanner unit 5 reads the document based on the detection of the reference mark provided on the intermediate transfer belt 22 by the reference position sensor 27, and the read image data is stored in the control unit 31. The data is sent to the central control unit 32 and stored in the image memory 33. The central control unit 32 forms a first color toner image on the photoconductor 18 based on the sent image data, and primarily transfers the toner image formed on the photoconductor 18 to the intermediate transfer belt 22. Subsequently, the central control unit 32 forms a second color toner image on the photosensitive member 18 based on the image data stored in the image memory 33, and primarily transfers the toner image formed on the photosensitive member 18 to the intermediate transfer belt 22. The image formation on the photoreceptor 18 and the primary transfer on the intermediate transfer belt 22 are repeated for each color. In other words, the intermediate transfer belt 22 is rotated twice when forming a two-color image, and the intermediate transfer belt 22 is rotated four times when forming a full-color image. The toner images are primarily transferred to the intermediate transfer belt 22 to superimpose the images of the respective colors without any positional deviation. After the toner image of a predetermined color is transferred to the intermediate transfer belt 22, the toner image is secondarily transferred to a recording sheet fed in accordance with the leading end of the toner image transferred to the intermediate transfer belt 22 and heated by the fixing unit 17. , Press to fix.
[0018]
As shown in the configuration diagram of FIG. 3A, each of the paper feed cassettes 28 a to 28 c of the paper feed unit 8 includes a drawing roller 31 provided on the top of the paper feeding cassette 28, and a recording sheet 32 from the drawing roller 31. A feed roller 33 provided on the downstream side in the transport direction, a reverse roller 34 provided opposite to the feed roller 33 across the transport path of the recording paper 32, and a rotation fulcrum 35 at the center. At both ends, there are a rotating arm 36 that rotatably holds the attracting roller 31 and the paper feeding roller 33, and a drive unit 37 such as a solenoid or a servo motor that rotates the rotating arm 36. Each of the paper feed cassettes 28 a to 28 c has a push-up arm 38 that is rotatable inside, and the push-up arm 38 pushes up the recording paper 32 stored in each of the paper feed cassettes 28 a to 28 c so The upper surface is positioned at a certain position. A paper feed motor 40 is attached to the rotation shaft of the paper feed roller 33 via a paper feed clutch 39. The feed roller 33 and the attracting roller 31 are connected by a timing belt 41, and the attracting roller 31 is also rotated by the rotation of the feed roller 33. A reflection type paper detection sensor 42 that detects the recording paper 32 being conveyed is provided on the downstream side of the paper feed roller 33. The reverse rotation roller 34 includes a torque limiter 43. When the paper feed roller 33 is in contact with the reverse rotation roller 34 and conveys the recording paper 32, the reverse rotation roller 34 and the paper feed roller 32 are caused by frictional force exceeding the torque of the torque limiter 43. When two or more recording sheets 32 are fed, the torque limiter 43 rotates to rotate the lower recording sheet 32 back.
[0019]
In each of the paper feed cassettes 28a to 28c configured as described above, when waiting for the recording paper 32 not being conveyed, as shown in FIG. The roller 31 is separated from the recording paper 32 stored in the paper feed cassette 28, and the paper feed roller 33 is separated from the reverse rotation roller 34. When the image forming process is started in the engine unit 7 of the digital copying machine 1 in this state, the rotation of the paper feeding motor 40 of the paper feeding cassette 28 is started, and at the same time, the driving unit 7 is operated as shown in FIG. The turning arm 36 is turned counterclockwise about the turning fulcrum 35, and the attracting roller 31 is brought into contact with the uppermost surface of the recording paper 32 stored in the paper feeding cassette 28. When the paper feeding clutch 39 is turned on in this state, the paper feeding roller 33 rotates, and the feeding roller 31 rotates with the rotation of the paper feeding roller 33 to pick up the uppermost recording paper 32 in the paper feeding cassette 28. Then, the sheet is fed to the nip portion between the paper feed roller 33 and the reverse rotation roller 34. When the recording paper 32 is sent between the paper feed roller 33 and the reverse rotation roller 34, the reverse rotation roller 34 acts to return the sent recording paper 32 to the upstream side, for example, two recording papers 32 are sent. In this case, only one recording sheet 32 is sent downstream so that the lower recording sheet 32 is not conveyed. When the leading end of the sent recording paper 32 is detected by the paper detection sensor 42, the drive unit 37 rotates the rotating arm 36 clockwise, and as shown in FIG. The sheet feed roller 33 is brought into contact with the reverse rotation roller 34 apart from the sheet 32, and the recording paper 32 is sandwiched and conveyed by the sheet feed roller 33 and the reverse rotation roller 34. When the recording paper 32 conveyed by the paper feed roller 33 passes the position of the paper feed roller 33 and the rear end of the conveyed recording paper 32 passes the position of the paper detection sensor 32, the drive unit 37 rotates. As shown in FIG. 4A, the moving arm 36 is rotated counterclockwise to return to the initial position, the paper feed roller 33 is separated from the reverse rotation roller 34, and the incoming arm 31 is stored in the paper feed cassette 28. The recording paper 32 is released.
[0020]
When the recording paper 32 stored in the paper feed cassette 28 is fed in this way, the rotation arm 36 is rotated by the drive unit 37 so that the attracting roller 31 is recorded in the paper feed cassette 28. Picking up and transporting the recording paper 32 stored in the paper feed cassette 28 can be performed by alternately switching between the paper 32 and the paper feed roller 33 and the reverse rotation roller 34. Can be switched by one drive unit 37, and the cost of the FRR separation / feeding mechanism of the sheet feeding cassette 28 can be reduced.
[0021]
[Embodiment 2] Next, an embodiment having a switching / positioning mechanism for rotating the rotation arm 36 to the paper feeding cassette 28 to position the incoming roller 31 and the paper feeding roller 33 will be described. As shown in the block diagram of FIG. 5, the switching / positioning mechanism 50 includes a rotation arm 36 having a rotation fulcrum 35 at the center and rotatably holding the attracting roller 31 and the paper feed roller 33 at both ends. The rotation gear 51, the position sensor 52, and the drive unit 37 that rotates the rotation gear 51 are included. The rotating arm 37 has an arm center portion 53 provided with a rotation fulcrum 35, and roller holding portions 54 for holding the drawing roller 31 and the paper feeding roller 33, and each roller holding portion 54 is a leaf spring for setting pressure. 55 is connected to the arm central portion 53. The rotation gear 51 has an arc-shaped gear portion 56 and a sensor arm 57 provided on the opposite side of the gear portion 56 with respect to the rotation center, and is fixed to the arm center portion 53 of the rotation arm 36. . The position sensor unit 52 includes a first position sensor 58a, a second position sensor 58b, and a third position sensor 58c. The first position sensor 58a regulates the position of the attracting roller 31 when the pivot arm 36 pivots, and the second position sensor 58b regulates the initial position of the pivot arm 36, and the third position sensor. 58c regulates the position of the paper feed roller 33 when the rotation arm 36 is rotated. The drive unit 37 includes a drive motor 59 formed of a pulse motor, and a reduction gear group 60 that is connected to the rotation shaft of the drive motor 59 and meshes with the gear unit 56 of the rotation gear 51.
[0022]
In the switching / positioning mechanism 50 configured as described above, when the digital copying machine 1 does not feed the recording paper 32 stored in the paper feeding cassette 28 in the standby state, the tip of the sensor arm 57 of the rotating gear 51 is At the position of the second position sensor 58 b of the position sensor unit 52, the attracting roller 31 is separated from the recording sheet 32 stored in the sheet feeding cassette 28, and the sheet feeding roller 33 is separated from the reverse rotation roller 34.
[0023]
  When the image forming process is started in the engine unit 7 of the digital copying machine 1 in this state, the rotation of the paper feed motor 40 of the paper feed cassette 28 is started and the drive motor 59 is rotated simultaneously so that the rotary gear 51 is turned counterclockwise. Rotate. Along with the rotation of the rotation gear 51, the rotation arm 36 also rotates counterclockwise, and the attracting roller 31 is brought into contact with the uppermost surface of the recording paper 32 stored in the paper feed cassette 28. Further, when the rotation gear 51 is rotated and the tip portion of the sensor arm 57 is detected by the first position sensor 58a, the rotation of the drive motor 59 is stopped. When the rotation of the drive motor 59 is stopped, the rotation gear 51 and the rotation arm 36 hold the position stopped by the holding force of the drive motor 59, and the contact pressure of the attracting roller 31 against the recording paper 32 is changed to the plate of the rotation arm 31. A constant pressure determined by the bending of the spring 55 is maintained. When the sheet feeding clutch 39 is turned on in this state, the sheet feeding roller 33 rotates, and the feeding roller 31 also rotates as the sheet feeding roller 33 rotates. The recording paper 32 at the top of the paper feed cassette 28 is picked up by the rotation of the feeding roller 31 and sent between the paper feed roller 33 and the reverse rotation roller 34. When the leading edge of the fed recording paper 32 is detected by the paper detection sensor 42, the drive motor 59 rotates the rotating arm 36 clockwise to rotate the rotating arm 36 clockwise to feed the paper feed roller 33. Is brought into contact with the reverse rotation roller 34. When the rotation gear 51 further rotates and the tip of the sensor arm 57 is detected by the third position sensor 58c, the rotation of the drive motor 59 is stopped, and the contact pressure of the paper feed roller 33 against the reverse rotation roller 34 is changed to the rotation arm. The constant pressure determined by the bending of the 36 leaf springs 55 is maintained. The recording paper 32 is conveyed by the rotation of the paper feed roller 33 that is in contact with the reverse rotation roller 34 at a constant pressure. When the recording paper 32 conveyed by the paper feed roller 33 passes the position of the paper feed roller 33 and the rear end of the recording paper 32 passes the position of the paper detection sensor 32, the drive motor 59 causes the rotation gear 51 to move.Rotate counterclockwise,As the rotation gear 51 rotates, the rotation arm 36 is rotated counterclockwise to release the contact between the paper feed roller 33 and the reverse rotation roller 34. When the rotation gear 51 rotates and the tip of the sensor arm 57 is detected by the second position sensor 58b, the drive motor 59 stops rotating and holds the rotation gear 59 and the rotation arm 36 at the initial positions. Thus, the attracting roller 31 is separated from the recording paper 32 stored in the paper feed cassette 28, and the paper feed roller 33 is separated from the reverse rotation roller 34.
[0024]
Thus, when the recording paper 32 stored in the paper cassette 28 is fed, the rotary arm 36 is rotated in accordance with the rotation of the rotary gear 51, and the attracting roller 31 is stored in the paper cassette 28. Since the recording paper 32 is brought into contact with the recording paper 32 with a constant contact pressure and the paper feed roller 33 is brought into contact with the reverse rotation roller 34 with a constant contact pressure, the recording paper 52 is stably fed one by one. The image formed by the engine unit 7 can be stably transferred to the recording paper 52.
[0025]
  [Embodiment 3] When the uppermost recording paper 32 in the paper feed cassette 28 is picked up by the rotation of the feeding roller 31 and sent to the nip portion of the paper feed roller 33 and the reverse rotation roller 34 as described above, the reverse rotation The roller 34 tries to return the recording paper 32 to the upstream side until the paper feed roller 33 comes into contact and is pressed. In order to prevent the recording paper 32 from being returned to the upstream side, as shown in FIG. 6, a separation plate 61 extending on both sides outside the width of the recording paper 32 in the width direction excluding the reverse rotation roller 34 is provided. It is preferable that the reverse rotation roller 34 is not in contact with the recording paper 32 fed to the nip portion between the paper feed roller 33 and the reverse rotation roller 34. The separation plate 61 has a fulcrum 62 at the center, and a spring 63 is attached to the opposite side of the contact portion with the recording paper 32. As shown in FIG. It is locked by a stopper 64 so as to lift the lower surface of the recording paper 32 slightly toward the paper feed roller 33 from the surface of the reverse rotation roller 34.The roller holding portion 54 that holds the paper feed roller 33 has a thrust plate 65 that extends from the vicinity of the shaft center toward the reverse rotation roller 34.As the rotation gear 51 rotates and the paper feed roller 33 moves toward the reverse rotation roller 34, the separation plate 61 isVeneer plate 65 of roller holder 54When the paper feed roller 33 is pressed down to the reverse rotation roller 34 side by contact with the reverse rotation roller 34, the contact portion of the separation plate 61 with the recording paper 32 is pivoted from the surface of the reverse rotation roller 34 as shown in FIG. The contact with the recording paper 32 is released by moving to the center side. In this way, since the reverse rotation roller 34 does not contact the recording paper 32 sent by the attracting roller 31 until the paper feed roller 33 comes into contact with the reverse rotation roller 34, the recording paper 32 sent by the attracting roller 31 is stabilized. Can be moved.
[0026]
【The invention's effect】
In the present invention, as described above, the attracting roller and the paper feed roller are held at both ends of a rotating arm having a pivoting fulcrum at the center, and the contact of the attracting roller with the recording paper and the contact of the paper feeding roller with the reverse rotation roller. By alternately switching the contact roller with respect to the recording paper and the contact roller with respect to the reverse rotation roller by rotating the rotation arm, the stacked recording paper is switched. The pickup and transport can be switched by a single drive unit, and the cost of the FRR separation / paper feeding mechanism can be reduced.
[0027]
Further, when the contact of the attracting roller with respect to the recording sheet is canceled by a sheet detection signal from a sheet detection sensor provided on the downstream side of the sheet feeding roller and the sheet feeding roller is brought into contact with the reverse rotation roller, The conveyance can be performed stably.
[0028]
In addition, the rotating arm has an initial position where the attracting roller does not contact the recording paper and the feed roller does not contact the reverse roller, the attracting position where the attracting roller contacts the recording paper, and the feed roller contacts the reverse roller. By positioning at the separating / feeding position, the recording paper can be stably pipped up and conveyed, and contact wear due to unnecessary rotation of each roller can be prevented. In addition, the recording paper can be easily set and removed, and when the recording paper is jammed during paper feeding, the recording paper on which the jam has occurred can be easily removed.
[0029]
  further,In the vicinity of both sides of the reverse rotation roller in the nip portion of the feed roller and reverse rotation roller, when the incoming roller is moving the recording paper in contact with the recording paper, the moving recording paper is lifted from the surface of the reverse rotation roller, Separation means for releasing the lifting of the recording paper by retreating from the recording paper conveyance path when the contact between the feeding roller and the recording paper is released and the paper feeding roller contacts the reverse rotation rollerBy providing the recording paper, the recording paper fed by the attracting roller can be stably moved.
[0030]
Further, by using this paper feeding device for an image forming apparatus such as a copying machine or a printer, it is possible to stably feed recording paper to the image forming unit and reduce the cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a configuration diagram of an engine unit.
FIG. 3 is a configuration diagram of a paper feeding unit.
FIG. 4 is an explanatory diagram illustrating an operation when a recording sheet is fed.
FIG. 5 is a configuration diagram of a second embodiment.
FIG. 6 is a configuration diagram of a third embodiment.
FIG. 7 is a configuration diagram of a conventional example.
[Explanation of symbols]
1; Digital copier, 2; Copier body, 3; ADF, 4; Automatic sorting device,
5; scanner unit, 6; writing unit, 7; engine unit, 8; paper feeding unit,
9: Printer unit, 14: Image forming unit, 15: Primary transfer unit,
16; secondary transfer unit, 17; fixing unit, 28; paper feed cassette,
31; Call-in roller, 32; Recording paper, 33; Paper feed roller,
34; reverse rotation roller, 35; rotation fulcrum, 36; rotation arm, 37; drive unit,
39; paper feed clutch; 40; paper feed motor; 41; timing belt;
42; paper detection sensor; 43; torque limiter.

Claims (4)

A feeding roller for moving the stacked recording paper, a paper feeding roller provided on the downstream side of the recording paper conveyance path from the calling roller, and a paper feeding roller provided across the recording paper conveyance path . A reversing roller, holding the attracting roller and the paper feeding roller at both ends of a pivoting arm having a pivoting fulcrum at the center, and contacting the recording roller with the recording paper and reversing the paper feeding roller A sheet feeding device that switches contact with a roller by rotation of the rotation arm,
In the vicinity of both sides of the reverse rotation roller in the nip portion of the paper feed roller and reverse rotation roller, when the incoming roller is moving the recording paper in contact with the recording paper, the moving recording paper is moved to the surface of the reverse rotation roller. And separating means for releasing the lifting of the recording sheet by retreating the recording sheet from the conveyance path when the feeding roller is released from contact with the recording sheet and the sheet feeding roller contacts the reverse rotation roller. Characteristic paper feeder. The invocation contact the recording paper roller, the paper sheet feeding according to claim 1, wherein to release the sheet detection signal from the sheet detection sensor provided on the downstream side contacting the feed roller to the reverse roller of the roller apparatus. Said pivot arm, not the invocation roller contacts the recording sheet, the initial position where the feed roller is also not in contact with the reverse roller, and the invocation position in contact with the recording sheet to the invocation roller, the paper feed roller The paper feeding device according to claim 1, wherein the paper feeding device is positioned at a separation / paper feeding position in contact with the reverse rotation roller. An image forming apparatus comprising the paper feeding device according to claim 1.

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