JP2010120740A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a recording sheet delivered between a paper feed roller and a separation roller from a paper feed cassette from breaking when the paper feed cassette is drawn out from a device body. <P>SOLUTION: In the state where the distal end part of the recording sheet housed in a first paper feed cassette 11 is sandwiched at a first-cassette-side paper feed nip between a first-cassette-side paper feed roller 12b and a first-cassette-side separation roller 12c contacting by pressure with each other, when a first paper feed cassette 11 is drawn out from the device body, the pressure contact of the first-cassette-side paper feed roller 12b and the first-cassette-side separation roller 12c is released with the drawing action. The distal end part of the recording sheet then moves with the first paper feed cassette 11, and abuts on a first sheet guide member 17, and therefore the recording sheet is guided on the downstream side of the delivery direction. Thus, the recording sheet is housed in the first paper feed cassette 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including an image processing unit that forms an image on a recording sheet such as recording paper, and a paper feeding unit that supplies a recording sheet stored in a paper feeding cassette to the image processing unit.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine of these, a recording sheet such as a recording sheet accommodated in a paper feeding cassette of a paper feeding unit is supplied to the image processing unit. The toner image corresponding to the image data is transferred and fixed on the supplied recording sheet. A sheet feeding cassette provided in the sheet feeding unit of such an image forming apparatus is normally detachable from the apparatus main body, and a recording sheet stored in the sheet feeding cassette is conveyed to the image processing unit. To do. The paper feed unit separates the pickup roller fed out from the paper feed cassette by rotating against the uppermost recording sheet stored in the paper feed cassette and the recording sheet fed out by the pickup roller one by one Thus, a pair of upper and lower paper feed rollers and a separation roller that are conveyed toward the image processing unit are provided.

  In such a copying machine, when a printing operation is continuously performed on a plurality of recording sheets accommodated in a paper feeding cassette, the uppermost recording sheet in the paper feeding cassette is fed out by a pickup roller. Then, the recording sheet is introduced into the sheet feeding nip between the sheet feeding roller and the separation roller that are in pressure contact with each other, and the separated recording sheet is conveyed to the image processing unit by the rotation of the sheet feeding roller and the separation roller. The paper is fed to a registration roller for adjusting the timing. When the trailing edge of the recording sheet fed to the registration roller passes through the sheet feeding nip, the leading edge of the next recording sheet positioned at the uppermost side in the sheet feeding cassette is fed out from the sheet feeding cassette by the pickup roller. Then, a standby state is introduced into the paper feed nip between the paper feed roller and the separation roller. In this standby state, the leading end portion of the recording sheet is sandwiched between the paper feed nips while passing through the paper feed nips for about 2 to 3 mm. After that, when the preceding recording sheet is conveyed to the image processing unit by the registration roller at a predetermined timing, the subsequent recording sheet with the leading end sandwiched in the sheet feeding nip is rotated by the rotation of the sheet feeding roller and the separation roller. Paper is fed up to. Thereafter, by repeating the same operation, the recording sheets are continuously conveyed from the paper feeding unit to the image processing unit, and toner images are continuously formed on the respective recording sheets in the image processing unit. .

  As described above, when the printing operation is interrupted in a state where the leading end portion of the recording sheet is sandwiched between the sheet feeding nips in order to continuously feed the recording sheet, replenishment of the recording sheet to the sheet feeding cassette, etc. Therefore, the user may pull out the paper feed cassette from the apparatus main body. At this time, the recording sheet having the leading end sandwiched between the feeding nips is pulled out of the main body of the apparatus, and the recording sheet portion located in the feeding cassette other than the leading end moves together with the feeding cassette. Further, since the leading end portion sandwiched between the sheet feeding nips does not move, there is a risk that the leading end portion of the recording sheet may be damaged.

Japanese Patent Application Laid-Open No. 2004-133867 describes a method for removing a jammed sheet when the leading edge is sandwiched between a pair of discharge rollers and the sheet is jammed between the fixing conveyance unit and the image forming apparatus main body. In addition, there is disclosed an image forming apparatus provided with a sheet guide member that guides the leading end of a sheet upward when the user pulls out the fixing conveyance unit from the main body of the image forming apparatus.
JP 2001-261189 A

  In the image forming apparatus described in Patent Document 1, when the fixing unit is pulled out from the image forming apparatus main body, the leading end portion of the sheet pulled out together with the fixing unit is smoothly caught without being caught by a member on the image forming apparatus main body side. It can be taken out together with the fixing conveyance unit. However, in the image forming apparatus disclosed in Patent Document 1, since the leading end of the sheet is sandwiched between the discharge roller pair, the user opens the release cover and removes the sheet by the discharge roller pair. There is a problem that it is necessary to release the pressure contact, and the operation is troublesome.

  As described above, when the leading end of the recording sheet is sandwiched in the sheet feeding nip in the sheet feeding unit, the leading end of the recording sheet sandwiched in the feeding nip is not a paper jam. Cannot be released. Also, if the recording sheet is damaged simply by pulling out the paper cassette, the user mistakes that the recording sheet has been damaged even though no paper jam has occurred, so that a malfunction such as a failure has occurred in the paper feeding unit. There is a fear. Furthermore, when a part of the damaged recording sheet remains in the sheet feeding nip, it is necessary to remove it, and there is a problem that the operation is troublesome.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to supply a recording sheet in a paper feed cassette between a paper feed rotating body such as a paper feed roller and a separation member such as a separation roller. An object of the present invention is to provide an image forming apparatus capable of preventing the recording sheet from being damaged without performing a special operation when the paper feeding cassette is pulled out from the apparatus main body while being fed to the paper nip. Yes.

  To achieve the above object, an image forming apparatus according to the present invention includes an image processing unit that forms an image on a recording sheet, and a paper feeding unit that supplies the recording sheet to the image processing unit. In the forming apparatus, the sheet feeding unit can be pulled out from the apparatus main body in which the image processing unit is provided, and includes a sheet feeding cassette in which a recording sheet is accommodated, and a recording sheet in the sheet feeding cassette A pick-up roller for feeding out the paper in a direction perpendicular to the pulling-out direction of the paper feed cassette, and a paper feed rotating body and a separating member that form a paper feed nip by being pressed against each other, and are fed out by the pick-up roller. While the recording sheet passes through the sheet feeding nip by the outer peripheral surface of the sheet feeding rotating body, the sheet is separated one by one toward the image processing unit. A paper feed means for the paper to, with the withdrawal from the apparatus main body of the paper feed cassette, and having a pressure contact releasing means for releasing the pressure contact between the separation member and the feeding rotary body.

  In the image forming apparatus of the present invention, when the sheet feeding cassette is pulled out from the apparatus main body with the leading end of the recording sheet sandwiched in the sheet feeding nip formed by the pressure contact between the sheet feeding rotating body and the separating member, As the paper cassette is withdrawn, the pressure contact releasing means releases the pressure contact state between the sheet feeding rotator and the separating member, so that the recording sheet whose leading end is located in the sheet feeding nip is fed out from the apparatus main body. The recording sheet is smoothly moved in the pulling direction together with the paper cassette, and the recording sheet is prevented from being damaged.

  Preferably, when a recording sheet having a leading end located at the sheet feeding nip moves together with the sheet feeding cassette pulled out from the apparatus main body, the recording sheet comes into contact with a side edge of the leading end of the recording sheet on the drawing direction side. And a sheet guide member provided in the apparatus main body, and the sheet guide member guides the abutting recording sheet in a direction opposite to a feeding direction by the pickup roller in accordance with the movement in the pull-out direction. It is characterized by that.

Preferably, the sheet guide member guides the leading end portion of the recording sheet at an inclination angle of 55 ° or more in the drawing direction with respect to a direction opposite to a feeding direction by the pickup roller.
Preferably, the side plate supporting the separation member on the drawing direction side of the apparatus main body is formed with a notch through which the leading end of the recording sheet that contacts the sheet guide member passes.

Preferably, the cutout portion is formed along a feeding direction of the pickup roller, and has a length of 17 mm or more from the paper feed nip in the feeding direction.
Preferably, a front side housing frame is disposed in the apparatus main body on the sheet feeding cassette drawing direction side with respect to the sheet guide member, and the sheet guide member includes a leading end portion of the recording sheet, It is made to move to the position which does not contact the said front side housing | casing frame.

Preferably, the sheet feeding cassette has side regulating members that regulate side edges on both sides in the drawing direction and the opposite direction of the recording sheet accommodated therein.
Preferably, the pressure release means is provided in the paper cassette and a frame that supports the separation member so as to be rotatable in a direction away from the paper feed rotating body, and the apparatus main body of the paper feed cassette And a release member that releases the pressure contact by separating the separation member from the sheet feeding rotating body by abutting with the frame as it is pulled out.

Preferably, the release member is in contact with the frame over a predetermined length along a pull-out direction of the paper feed cassette.
Preferably, the paper feeding unit includes a cover member that covers the paper feeding rotator and the separation member on the downstream side in the conveyance direction of the recording sheet by the paper feeding rotator and the separation member. The paper nip is movable so as to be exposed to the outside.

  Preferably, two sets of the sheet feeding units are provided, and the two sets of sheet feeding units are arranged side by side in the vertical direction.

  FIG. 1 is a schematic front view showing an internal configuration of a tandem color digital copying machine which is an example of an image forming apparatus according to the present invention. The copying machine shown in FIG. 1 includes a sheet supply mechanism A provided at the bottom, an image process unit B provided on the sheet supply mechanism A, and an image reading unit C provided on the image process unit B. When a print execution instruction (print job) is received from a terminal device or operation panel connected to a network (for example, an in-house LAN) or the like, based on the image data from the terminal device according to the instruction, or Based on the image data of the original read by the image reading unit C, a toner image is formed on the recording sheet supplied from the sheet supply mechanism A in the image processing unit B.

  The image processing unit B is arranged in order from the upstream side along the circumferential movement direction of the intermediate transfer belt 51 under the intermediate transfer belt 51, and the intermediate transfer belt 51 that rotates in the direction indicated by the arrow N. The image forming units 52Y, 52M, 52C, and 52K and the image forming units 52Y, 52M, 52C, and 52K are disposed below the image forming units 52Y, 52M, 52C, and 52K to irradiate the laser beams L, respectively. The exposure apparatus 53 is provided. The intermediate transfer belt 51 is wound around a driven roller 54 disposed close to the image forming unit 52Y and a driving roller 55 disposed close to the image forming unit 52K. The driving roller 55 is not shown. By being rotationally driven by the motor, it moves around in the direction indicated by the arrow N. The intermediate transfer belt 51 has conductivity.

  The image forming unit 52Y disposed on the upstream side in the moving direction of the intermediate transfer belt 51 includes a photosensitive drum 56Y, and forms a toner image on the photosensitive drum 56Y by a known electrophotographic method. That is, an electrostatic latent image is formed on the surface of the photosensitive drum 56Y by irradiating the photosensitive drum 56Y charged by the charger with the laser beam L from the exposure device 53, and the electrostatic latent image is formed. Is developed with yellow (Y) toner by a developing device, thereby forming a Y toner image.

The other image forming units 56M, 56C, and 56K have the same configuration as that of the image forming unit 56Y. Magenta (M) is formed on the photosensitive drums 56M, 56C, and 56K through charging, exposure, and development processes. , Cyan (C), and black (K) toner images are formed.
In the copying machine according to the present embodiment, a monochrome mode in which a monochrome image is formed using toner of one color (for example, K color), and a color in which a color image is formed using toners of four colors Y, M, C, and K. It is possible to switch between modes. In the image forming operation in the color mode, the image forming units 52Y, 52M, 52C, and 52K are formed on the outer peripheral surfaces of the photosensitive drums 56Y, 56M, 56C, and 56K that are rotationally driven at a predetermined peripheral speed. The Y, M, C, and K color toner images are transferred onto the same area of the intermediate transfer belt 51 in an overlapping manner. In the case of an image forming operation in the monochrome mode, a toner image formed by one selected image forming unit is transferred onto a predetermined area on the intermediate transfer belt 51. A secondary transfer roller 58 is disposed so as to face the drive roller 55 that rotates the intermediate transfer belt 51 around the intermediate transfer belt 51, and the secondary transfer roller 58 and the drive roller 55 are arranged on the circumferential surface of the secondary transfer roller 58. A transfer nip N1 that forms a secondary transfer portion that transfers a toner image onto a recording sheet is formed between the circumferential transfer area of the intermediate transfer belt 51 along.

Above the intermediate transfer belt 51, hoppers 57Y, 57M, 57C, and 57K that store toner of each color of Y, M, C, and K are provided, and are accommodated in the hoppers 57Y, 57M, 57C, and 57K, respectively. The toner of each color is supplied to the developing devices of the image forming units 52Y, 52M, 52C, and 52K.
A sheet supply mechanism A provided below the image processing unit B includes a first paper feeding unit 10 disposed below the exposure device 53 and a second paper feeding disposed below the first paper feeding unit 10. The paper feeding unit 20 includes a third paper feeding unit 30 and a fourth paper feeding unit 40 which are disposed further below the second paper feeding unit 20. From each of the first to fourth paper feeding units 10 to 40, recording sheets are conveyed one by one toward the image processing unit B, and intermediate transfer in the image processing unit B is performed at a predetermined timing by a pair of registration rollers 66. It is conveyed to a transfer nip N1 between the belt 51 and the secondary transfer roller 58. Then, while the recording sheet passes through the transfer nip N1, the toner image transferred onto the intermediate transfer belt 51 is secondarily transferred to the recording sheet by the secondary transfer roller 58. The recording sheet that has passed through the transfer nip N1 is supplied to a fixing unit 59 provided above the transfer nip N1.

  The fixing unit 59 includes, for example, a heating roller 59a and a pressure roller 59b that are pressed against each other, and a fixing nip N2 is formed therebetween. The toner image transferred to the recording sheet is heat-fixed on the recording sheet by being heated and pressurized while the recording sheet passes through the fixing nip N2. A paper discharge tray 61 is provided on each of the hoppers 57Y, 57M, 57C, and 57K provided in the image processing section B, and an appropriate space is provided above the paper discharge tray 61. The heat-fixed recording sheet is discharged onto the paper discharge tray 61 by the paper discharge roller pair 62.

  Note that, above the paper discharge tray 61, the recording sheet is switched back during double-sided copying in which a toner image is formed on the other side (back side) of the recording sheet on which one side (front side) is formed. A guide 64 is provided for use as an auxiliary. At the time of double-sided copying, the recording sheet on which the toner image is thermally fixed in the fixing unit 59 is conveyed to a reversing roller pair 65 provided above the paper discharge roller pair 62 and is sent onto the guide 64 by the reversing roller pair 65. Then, the leading end of the recording sheet is guided on the guide 64. The reverse roller pair 65 is switched to reverse rotation immediately before the trailing edge of the recording sheet passes. As a result, the recording sheet is switched back and sent to the circulation path 63. The circulation path 63 is a path for circulating the switched back recording sheet to the transfer nip N1 so as to reverse the front and back, and is provided so as to pass the side of the fixing unit 59 along the vertical direction. Yes. The recording sheet sent to the guide 64 is conveyed to the pair of registration rollers 66 with the front and back being reversed.

  The first paper feed unit 10 provided on the upper part of the sheet supply mechanism A includes a first paper feed cassette 11 mounted in a substantially horizontal state in the apparatus main body below the exposure device 53, and a first paper feed cassette. A first sheet feeding unit 12 that feeds recording sheets stored in the sheet 11 one by one, and a first sheet that conveys a recording sheet fed from the first sheet feeding unit 12 toward the upper image processing unit B. A transport unit 13 and a manual feed unit 14 for manually feeding a recording sheet to the first transport unit 13 from the outside of the apparatus main body are provided. The first paper feed cassette 11 is pulled forward from the front side (front side) of the apparatus main body, so that the attachment to the apparatus main body in which the image processing unit B and the image reading unit C are provided is released. The first paper feed cassette 11 removed from the main body is inserted into the apparatus main body by being inserted from the front side of the apparatus main body toward the back side (back side). The other paper feed cassettes have the same configuration. In the following, the front side and the back side of the apparatus main body are simply referred to as “front side” and “back side”, respectively, and the right side and the left side in the insertion direction of the first paper feed cassette 11 with respect to the apparatus main body are These are simply referred to as “right side” and “left side”, respectively.

In the apparatus main body, a first paper supply unit 12 is arranged from the upper side on the right side of the first paper supply cassette 11 mounted on the apparatus main body to the right side, and recording in the first paper supply cassette 11 is performed. The sheets are conveyed one by one by the first sheet feeding unit 12 toward the first conveying unit 13 disposed obliquely above and to the right of the first sheet feeding unit 12.
The second paper feed unit 20 provided below the first paper feed unit 10 includes a second paper feed cassette 21 mounted in the apparatus main body below the first paper feed cassette 11 and a second paper feed. In order to feed out the recording sheets stored in the cassette 21 one by one, a second paper feeding unit 22 provided from the upper side of the right side of the second paper feeding cassette 21 to the right side, and a second paper feeding unit 22 is provided with a second transport unit 23 that transports the recording sheet fed out from the head 22 toward the first transport unit 13 in the upper first paper feed unit 10.

  Below the second paper feed unit 20, a third paper feed unit 30 and a fourth paper feed unit 40 arranged side by side on the right side and the left side are provided. The third paper feeding unit 30 arranged on the right side is accommodated in the third paper feeding cassette 31 and the third paper feeding cassette 31 detachably arranged on the right side below the second paper feeding cassette 21. In order to feed the recording sheets one by one, a third paper feeding unit 32 provided on the upper right side of the third paper feeding cassette 31 and a recording sheet fed from the third paper feeding unit 32 are fed to the upper second paper feeding. And a third transport unit 33 that transports toward the second transport unit 23 in the unit 20. The fourth paper feed unit 40 disposed on the left side of the third paper feed cassette 31 includes a fourth paper feed cassette 41 disposed on the left side of the third paper feed cassette 31 in the apparatus main body, and a fourth paper feed cassette 41. In order to feed out the recording sheets stored in the sheet one by one, the fourth sheet feeding unit 42 provided on the upper right side of the fourth sheet feeding cassette 41 and the recording sheet fed out from the fourth sheet feeding unit 42 A fourth conveying unit 43 that conveys the upper area of the three sheet feeding cassettes 31 toward the right side; and a second conveying unit 23 in the upper second sheet feeding unit 20 that conveys the recording sheet conveyed by the fourth conveying unit 43. And a fifth transport unit 44 for transporting toward the head.

  FIG. 2 is a cross-sectional view illustrating a specific configuration of the first sheet feeding unit 10 disposed on the upper portion of the sheet supply mechanism A. As illustrated in FIG. Inside the first paper feed cassette 11, there is provided a cassette paper feed base 11a on which recording sheets of a predetermined size are stacked and placed in the vertical direction. The cassette paper feed stand 11a is biased upward in the insertion direction of the first paper feed cassette 11 (the paper feed direction side portion) so that the right side is positioned upward. It is in an inclined state.

  The first sheet feeding unit 12 includes a first cassette side pickup roller 12a in which the right side portion of the uppermost recording sheet placed on the cassette sheet feeding base 11a is pressed, and a right side of the first cassette side pickup roller 12a. The first cassette side paper feed roller 12b disposed on the side of the first cassette side, and a first cassette side separation roller 12c that presses against the first cassette side paper feed roller 12b from below. A pickup roller 12a, a first cassette side paper feed roller 12b, and a first cassette side separation roller 12c are attached to the apparatus main body. The recording sheet fed from the first paper feed cassette 11 by the first cassette side pickup roller 12a is a first cassette between the first cassette side paper feed roller 12b and the first cassette side separation roller 12c that are pressed against each other. The sheet is supplied to the side sheet feeding nip, and only one recording sheet is separated and passes through the first cassette side sheet feeding nip.

  FIG. 3 is an enlarged cross-sectional view of the right side portion of the first paper feed unit 12 and its peripheral portion. As shown in FIG. 3, on the downstream side (right side) of the first cassette side sheet feeding roller 12b and the first cassette side separation roller 12c in the recording sheet conveying direction, one recording sheet that has passed between them is tilted to the right. A cassette-side first transport guide 12f that guides upward is provided. The cassette-side first conveyance guide 12f is in contact with the leading end of one recording sheet that has passed through the first cassette-side feeding nip between the first cassette-side feeding roller 12b and the first cassette-side separation roller 12c. A guide surface of the recording sheet inclined at an inclination angle of about 26 ° with respect to the horizontal line is provided so as to guide the leading end thereof obliquely upward to the right by contacting. On the right side of the cassette-side first conveyance guide 12f, there is a first sheet feeding unit cover 12d that forms a first conveyance path 15 through which a recording sheet conveyed upward from the second sheet feeding unit 20 passes. It is provided in a substantially vertical state. A manual feed unit 14 is provided horizontally on the right side of the first paper feed unit cover 12d. The manual feed unit 14 is provided with a first transport path 15 together with the first paper feed unit cover 12d. The manual feed unit main body cover 14c to be formed is provided in a substantially vertical state. The lower ends of the first paper feed unit cover 12d and the manual feed unit main body cover 14c are sequentially separated toward the lower side so that the recording sheet conveyed from the lower side can be easily introduced into the first conveyance path 15. Are inclined in opposite directions.

  A cassette-side second conveyance guide 12h that guides the recording sheet guided by the cassette-side first conveyance guide 12f further upward is provided at the upper end of the first sheet-feeding unit cover 12d. 12d is formed integrally. The cassette-side second conveyance guide 12h is a recording sheet inclined at an inclination angle of about 50 ° (40 ° with respect to the horizontal line) with respect to the first paper supply unit cover 12d from the upper end of the first paper supply unit cover 12d. A guide surface is provided. The guide surface of the recording sheet of the cassette-side second conveyance guide 12h is guided so that the leading edge of the recording sheet guided by the cassette-side first conveyance guide 12f abuts further upward. In addition, the cassette side first transport guide 12f is inclined at a larger angle with respect to the horizontal line than the guide surface of the recording sheet.

  A film-like flexible guide 12k is attached to the upper end portion of the first paper feed unit cover 12d so as to extend upward along the first paper feed unit cover 12d. The flexible guide 12k is made of, for example, a flexible PET film (trade name “Mylar”, manufactured by Teijin DuPont Films Ltd.), and is formed long along the width direction perpendicular to the recording sheet conveyance direction. It is attached in a state where it is inclined slightly upward to the right with respect to the vertical direction.

  The first paper feed unit cover 12d is supported by the apparatus main body so that the upper end of the first paper feed unit cover 12d can be rotated obliquely downward to the right. As shown in FIG. 4, the upper end portion is rotated obliquely downward to the right from the substantially vertical state along the vertical direction while being rotated in the horizontal direction so as to be separated from one paper feeding unit 12. In addition, the first cassette-side paper feed nip between the first cassette-side paper feed roller 12b and the first cassette-side separation roller 12c is exposed to the outside of the apparatus main body. As a result, even if the recording sheet is jammed (JAM) in the first cassette-side sheet feeding nip, the recording sheet can be easily removed.

  Above the first paper feed unit cover 12d, the recording sheet fed by the first cassette side paper feed roller 12b and the first cassette side separation roller 12c and the first transport path 15 are transported upward. A first transport unit 13 is provided for transporting the recording sheet to be moved toward the upper image processing section B. The first transport unit 13 includes a first transport drive roller 13a disposed on the left side above the first transport path 15, and a first transport driven roller 13b disposed on the right side of the first transport drive roller 13a. ing. The first conveyance driven roller 13b is movable between a state in which it is pressed against the first conveyance driving roller 13a and a state in which the first conveyance driven roller 13b is separated from the first conveyance driving roller 13a. A conveying nip is formed between the two by being pressed against the driving roller 13a.

  As shown in FIG. 2, the manual feed unit 14 provided on the first paper supply unit 12 facing the right side of the first paper supply unit cover 12d sandwiches the first conveyance path 15 between the first paper supply unit cover 12d. And a manual feed tray 14b supported by the manual feed unit main body 14a so as to extend rightward from the manual feed unit main body 14a. The manual feed unit main body 14a is arranged in a horizontal state from the front to the back of the apparatus main body, and a rear side housing frame whose end on the back side is provided on the right side on the back side of the apparatus main body. (Not shown) is supported so as to be rotatable around a vertical axis while maintaining a horizontal state. The manual feed unit main body 14a is rotated between a state facing the first paper feed unit 12 and a state of being separated from the first paper feed unit 12 while maintaining a horizontal state around the vertical axis. By rotating the manual feed unit main body 14a, the first paper feed unit cover 12d provided in a substantially vertical state on the first paper feed unit 12 is exposed to the outside of the apparatus main body.

  As described above, the manual feed unit main body portion 14 a has the first paper feed unit provided in the first paper feed unit 12 when the manual feed unit main body portion 14 a is opposed to the first paper feed unit 12. A manual feed unit body cover 14c that forms the first transport path 15 is provided in a substantially vertical state between the cover 12d and the cover 12d. As shown in FIG. 2, a manual pickup roller 14e that feeds a recording sheet placed on the manual feed tray 14b obliquely upward to the left and a manual pickup roller 14e are fed to the manual feed unit 14a. A pair of upper and lower manual feed rollers 14f and a manual separation roller 14g are provided for transporting the recorded sheet to the first transport unit 13 via the flexible guide 12k. The recording sheet that has passed through the first manual feed nip between the manual feed roller 14f and the manual separation roller 14g is fed by the flexible guide 12k to the first transport drive roller 13a and the first transport of the first transport unit 13. It is conveyed to the conveyance nip between the driven rollers 13b.

  FIG. 5A is a schematic cross-sectional view for explaining the configuration in the vicinity of the first paper feed cassette 11 in the first paper feed unit 12, and FIG. In FIGS. 5A and 5B, the first paper supply unit cover 12d is removed. The first cassette-side paper feed roller 12b and the first cassette-side separation roller 12c provided in the first paper feed unit 12 have a first feed at a central portion in a direction (recording sheet width direction) perpendicular to the feeding direction. The axial lengths are equal to each other so as to come into contact with the central portion in the width direction of the recording sheet fed out from the paper cassette 11. The first cassette-side separation roller 12c disposed below the first cassette-side paper feed roller 12b is integrally attached to the separation roller support frame 12m, and the separation roller support frame 12m is separated from the first cassette-side separation. It is supported by the apparatus main body so as to be rotatable around a second support pin 12g provided obliquely above and to the right of the roller 12c. The lower part of the separation roller support frame 12m is pressed toward the first paper feed cassette 11 by the urging force of the compression spring 12p, and the separation roller support frame 12m is pressed by the compression spring 12p, so that the first The cassette side separation roller 12c is pressed against the first cassette side paper supply roller 12b. The separation roller support frame 12m is provided with an operation lever 12n that is operated when the separation roller support frame 12m is rotated. The operation lever 12n is disposed slightly below the first cassette-side separation roller 12c on the back surface side of the first cassette-side separation roller 12c, and the leading end is on the feeding direction side of the first sheet feeding cassette 11. It is close to the sheet feeding side surface 11b.

  FIG. 6A is a side view showing the sheet feeding side surface 11b of the first sheet feeding cassette 11 together with the first cassette side sheet feeding roller 12b and the first cassette side separation roller 12c on the apparatus main body side, and the operation lever 12n. FIG. 6B is a diagram for explaining the operation. The separation roller support frame 12m is not shown. The front end of the operation lever 12n on the front side of the apparatus main body is a position about several millimeters away from the first cassette side separation roller 12c to the back side of the apparatus main body, and below the first cassette side separation roller 12c. The first cassette side separation roller 12c protrudes from the outer peripheral surface toward the first paper feed cassette 11 (see FIG. 5). An outer surface of the first sheet cassette 11 on the sheet feeding side surface 11b abuts on the upper surface of the operation lever 12n when the first sheet cassette 11 is pulled out from the apparatus main body, and the operation lever 12n is pulled along with the drawing. A release rib 11c is provided to push down the button. The release rib 11c is formed on the outer surface of the sheet feeding side surface 11b in the first sheet feeding cassette 11 so as to protrude outward in a horizontal linear state over a predetermined length (see FIG. 5). The upper surface of the operation lever 12n that contacts the release rib 11c is provided continuously at the center flat surface provided at a constant height in the center portion in the front-rear direction and the front side of the center flat surface, A front side inclined surface which is inclined so as to be gradually lower, and a back side inclined surface which is continuously provided on the back side of the central flat surface and which is inclined so as to become gradually lower toward the back side. Yes. The front end of the release rib 11c provided in the first paper feed cassette 11 is 11 on the end of the inclined surface on the back side of the operation lever 12n when the first paper feed cassette 11 is mounted on the apparatus main body. Further, the end portion of the inclined surface on the front side and the lower surface of the release rib 11c are at the same height. The rear-side end of the release rib 11c extends to the vicinity of the rear-side end on the paper-feeding side surface 11b.

  As shown in FIG. 6A, in the state where the first paper feed cassette 11 is mounted on the apparatus main body, the release rib 11c does not push down the operation lever 12n. The separation roller support frame 12m is rotated about the second support pin 12g by the urging force of the compression spring 12p, and the first cassette side separation roller 12c is pressed against the first cassette side paper feed roller 12b. In this state, when the first paper feed cassette 11 is pulled out from the apparatus main body, the release rib 11c provided on the paper feed side surface 11b is brought into sliding contact with the rear side inclined surface on the upper surface of the operation lever 12n. The lever 12n is sequentially pushed downward. Thereafter, the first paper feed cassette 11 is pulled out from the apparatus main body by the length of the back side inclined surface (11.6 mm), so that the release rib 11c is in contact with the central flat surface on the upper surface of the operation lever 12n. Thus, the operation lever 12n is pushed downward by a predetermined distance. As a result, as shown in FIG. 5B, the separation roller support frame 12m rotates against the urging force of the compression spring 12p so that the first cassette side separation roller 12c moves away from the first cassette side paper supply roller 12b. The first cassette side separation roller 12c is moved away from the first cassette side paper supply roller 12b by, for example, 1.9 mm. Thereafter, while the first paper feed cassette 11 is further pulled out from the apparatus main body, the central flat surface on the upper surface of the operation lever 12n is kept downward by maintaining the sliding contact state with the release rib 11c formed in the horizontal state. The first cassette side separation roller 12c maintains a state of being separated from the first cassette side paper supply roller 12b. Thereafter, the first paper feed cassette 11 is further pulled out from the apparatus main body, so that the end portion on the back side of the first release rib 11c comes into sliding contact with the front inclined surface from the central flat surface on the upper surface of the operation lever 12n. The operation lever 12n is gradually rotated upward, and the contact state between the first release rib 11c and the operation lever 12n is released as shown in FIG. 6B. Thus, the separation roller support frame 12m is rotated around the second support pin 12g by the pressing force of the compression spring 12p, and the first cassette side separation roller 12c is again pressed against the first cassette side paper feed roller 12b. (See FIG. 5 (a)).

  FIG. 7 is a plan view of a sheet feeding side portion of the first sheet feeding cassette 11 in a state where the first sheet feeding cassette 11 is mounted on the apparatus main body. The first paper feed cassette 11 has the same configuration as the conventional paper feed cassette except that a release rib 11c is provided on the back side of the paper feed side surface 11b. In order to align the side edges on both sides in the width direction perpendicular to the feeding direction (paper feeding direction) of a plurality of recording sheets placed on the cassette paper feeding table 11a, the inside of the cassette 11 is arranged on each side. A side regulating plate 11d that abuts the edge and regulates the position of each side edge is provided along the feeding direction with a sense in the width direction of the recording sheet.

  FIG. 8 is a plan view of the front side portion of the sheet supply mechanism A, and FIG. 9 is a perspective view thereof. As shown in FIGS. 8 and 9, the paper feeding unit 12 includes a front-side housing frame 16 arranged vertically on the front side and a rear-side housing provided on the back side on the right side of the apparatus main body. It is disposed between the body frame (not shown). FIG. 10 is a perspective view showing front side portions of the first paper supply unit 10 and the second paper supply unit 20 in the sheet supply mechanism A, and FIG. 11 is a front view thereof. In FIG. 11, the detailed configuration of the manual feed unit 14 is omitted. As shown in FIGS. 10 and 11, the first paper supply unit 10 provided in the upper part of the sheet supply mechanism A has a front side surface of the first paper supply unit 12 and the first transport unit 13. The cassette side paper feed roller 12b and the first cassette side separation roller 12c are covered with a first side plate 10a that supports front side portions. The first side plate 10a has a side plate main body portion 10b and a side plate feeding side portion 10c extending horizontally from the middle in the vertical direction of the side plate main body portion 10b to the left side. The side plate main body 10b is formed from the lower end of the first paper feed unit cover 12d to the upper end of the first transport unit 13 except for the first cassette side pickup roller 12a and the first cassette side paper feed roller 12b in the first paper feed unit 12. It is comprised in the vertically long rectangular shape which covers the whole front side part to a part. The side plate feeding side portion 10c is configured in a horizontally long rectangular shape so as to cover the front side portions of the first cassette side pickup roller 12a and the first cassette side feeding roller 12b. As shown in FIG. 11, the lower side edge of the side plate feeding side portion 10c is substantially horizontal at a predetermined height position between the axial center portion and the lower end portion of the first cassette side feeding roller 12b. It has become.

  An end on the feeding direction side (right side) of the lower side edge of the side plate feeding side portion 10c is disposed corresponding to a position close to the right end of the first cassette side feeding roller 12b. The side plate main body 10b includes an upper portion that covers the front side portion of the first transport unit 13 above the side plate feeding side portion 10c, and a first portion of the first sheet feeding unit 12 below the side plate feeding side portion 10c. A first cassette side separation roller 12c and a lower portion covering the front side portion of the first paper feed unit cover 12d, and the left side edge of the lower portion is the axial center position of the first cassette side paper feed roller 12b And a position substantially corresponding to the vertical direction at a position corresponding to an intermediate position between the left end portion and the left end portion.

  The first side plate 10a is provided with a first notch 10d. The first cutout portion 10d is such that the leading end of the recording sheet sandwiched by the first cassette-side paper feed nip between the first cassette-side paper feed roller 12b and the first cassette-side separation roller 12c is pulled out from the apparatus main body. The first sheet feeding cassette 11 is provided so as to pass through the first side plate 10a when moving in the pulling-out direction. The first cutout portion 10d includes an upper inclined side edge 10e extending linearly in an inclined state from the lower side edge of the side plate feeding side portion 10c in a horizontal state toward the upper right side (upward in the feeding direction). An upper horizontal side edge 10f extending horizontally in the right direction from the right end portion of the upper inclined side edge 10e, and a lower left side (upstream in the feeding direction) from the right end portion of the upper horizontal side edge 10f. The lower inclined side edge 10g extending linearly in the inclined state toward the lower side), and the upstream side portion in the feeding direction is opened obliquely to the lower left side (upward lower side in the feeding direction). .

  The upper horizontal side edge 10f of the first notch 10d is at a height position corresponding to slightly below the axis of the first cassette-side paper feed roller 12b. The lower inclined side edge 10g continuous with the upper horizontal side edge 10f is inclined in a state substantially along the recording sheet feeding direction by the cassette-side first conveyance guide 12f, and the inclination angle with respect to the horizontal line is the upper inclined side edge. It is slightly smaller than 10e. The lower inclined side edge 10g is inclined at a position corresponding to a substantially middle position between the upper end portion of the first cassette-side separation roller 12c and the axial center position along the extension line of the cassette-side first conveyance guide 12f. The end portion on the opening side is continuous with the left side edge that is in the vertical state in the lower portion of the side plate body 10b at the substantially same height as the axis of the first cassette side separation roller 12c. ing. As described above, the first notch 10d formed in the first side plate 10a has the first cassette-side feed roller 12b and the first cassette-side separation roller 12c pressed against each other from the upstream opening on the feed side. In addition, it is formed in an inclined state along the conveyance direction of the recording sheet conveyed through the first cassette side sheet feeding nip. In this case, the end of the upper horizontal side edge 10f on the feeding direction side is, for example, downstream from the first sheet feeding nip with a distance of 17 mm or more along the lower inclined side edge 10g (feeding direction). Has been placed.

As shown in FIGS. 8 to 10, on the front side surface of the first side plate 10a, the leading end of the recording sheet that has passed through the first notch 10d by moving in the pulling direction is moved in the pulling direction. Accordingly, the first sheet guide member 17 for sequentially guiding the upstream side in the feeding direction (left side direction) is attached so as to cover the first notch portion 10d.
FIG. 12A is a perspective view of the first sheet cassette 11 viewed from the upstream side in the feeding direction, with the first sheet guide member 17 attached to the side plate body 10b removed, and FIG. FIG. 5 is a perspective view of the first sheet guide member 17 as viewed from the downstream side in the feeding direction. The first sheet guide member 17 has a bracket portion 17a attached to the lower side of the first notch portion 10d provided in the side plate main body portion 10b, and an upper inclined side edge of the bracket portion 17a to the side plate main body portion 10b. A substantially triangular plate-like lower guide portion 17b extending in a direction away from the first paper feed cassette 11 (the pulling direction of the first paper feed cassette 11) and a vertical state along the side edge of the lower guide portion 17b located on the pulling direction side The plate-shaped side guide portion 17c and the plate-shaped upper guide portion 17e disposed to face the lower guide portion 17b with a predetermined distance therebetween are provided.

  The bracket portion 17a is screwed to the side plate body portion 10b in a state where the upper side edge is positioned along the lower inclined side edge 10g of the first notch portion 10d provided in the side plate body portion 10b. ing. The upper side edge of the bracket portion 17a attached to the side plate main body portion 10b is in the same inclined state as the lower inclined side edge 10g of the first cutout portion 10d and has the same length. The side edge located on the opposite side to the pulling direction in the lower guide part 17b is the same as the upper side edge of the bracket part 17a. The side guide portions 17c in the vertical state are sequentially positioned on the drawing direction side from the downstream end in the feeding direction (paper feeding direction) at the upper inclined side edge of the bracket portion 17a toward the upstream in the feeding direction. In an inclined state, it extends to the upstream side in the feeding direction. The inclination angle with respect to the feeding direction of the side guide portion 17c is slightly larger in the portion close to the upper side edge of the bracket portion 17a than in the other portions. As shown, the inclination angle is, for example, 55 ° with respect to a straight line along the direction opposite to the feeding direction. Therefore, the portion close to the upper side edge of the bracket portion 17a has an inclination angle of 55 ° or more. Note that the side edge of the lower guide portion 17b on the upstream side in the feeding direction is in a horizontal state along the pulling direction.

  The first sheet guide member 17 has an upper side edge of the bracket portion 17a, a vertical side edge of the side guide portion 17c continuous to the bracket portion 17a, and a side opposite to the pulling direction of the upper guide portion 17e. Are formed on the side plate main body portion 10b side, and the side edges located on the upstream side of the lower guide portion 17b and the upper guide portion 17e in the extending direction are respectively formed. A second side opening that is in communication with the first opening and opened to the upstream side in the feeding direction is formed by the vertical side edge located on the upstream side in the feeding direction of the side guide portion 17c. The periphery of the second opening is reinforced by a reinforcing plate 17f that is in a vertical state except for the side portion on the first opening side, and the upper guide portion 17e is horizontally connected to the reinforcing plate 17f. It is covered with an upper surface cover 17g.

  The first sheet guide member 17 is attached to the side plate body 10b so that the first opening is opposed to the first notch 10d provided in the side plate body 10b. In this case, as shown in FIGS. 8 and 9, the side edge of the lower guide portion 17b on the upstream side in the feeding direction, and therefore the end portion of the side guide portion 17c on the upstream side in the feeding direction, It protrudes slightly upstream from the side surface located upstream in the feed-out direction.

  Note that the second paper feed unit 20 provided below the first paper feed unit 10 has a configuration of the second paper feed cassette 21, a configuration of the second paper feed unit 22, and a configuration of the second transport unit 23, respectively. Is the same as the configuration of the first sheet feeding cassette 11, the configuration of the first sheet feeding unit 12, and the configuration of the first transport unit 13 in the first sheet feeding unit 10. As shown in FIG. The paper feed unit 22 feeds the recording sheets in the second paper feed cassette 21 to the second paper feed nip between the second paper feed roller 22b and the second separation roller 22c, which are pressed against each other. The second sheet feeding roller 22b and the second separation roller 22c are rotated to pass through the second sheet feeding nip and are conveyed to the second conveying unit 23. The second paper feed cassette 21 has a second release rib that comes into contact with a second operation lever 22n for releasing the pressure contact state of the second separation roller 22c with the second paper feed roller 22b when the second paper feed cassette 21 is pulled out from the apparatus main body. 21d is provided. The second front cover 20a that covers the front side portions of the second paper feed unit 22 and the second transport unit 23 is provided with a second cutout portion 20d having the same configuration as the first cutout portion 10d. A second sheet guide member 27 (see FIG. 10) having the same configuration as that of the one sheet guide member 17 is attached.

  Further, as shown in FIG. 11, the second sheet feeding unit 20 conveys a recording sheet fed by the third sheet feeding unit 30 and the fourth sheet feeding unit 40 to the second conveyance unit 23. A conveyance path 25 is provided. The second transport path 25 includes a second paper feed unit cover 22d that covers a right side portion (a side portion on the downstream side in the feeding direction) of the second paper feed roller 22b and the second separation roller 22c in the second paper feed unit 22. , And a second transport path guide 26a disposed to face the second paper feed unit cover 22d. The second transport path guide 26a is provided integrally with a second paper feed section door 26 that is rotatably attached to the apparatus main body so as to open the second paper feed unit cover 22d. The second transport driven roller 23b facing the second transport driving roller 23a in the second transport unit 23 is attached to the second paper feed section door 26, and the second paper feed section door 26 is the second paper feed section. By rotating with respect to the apparatus main body so as to open the unit cover 22d, the pressure contact state with the second transport driving roller 23a is released.

  As shown in FIG. 1, the recording sheet in the third cassette 31 in the third paper feed unit 30 passes through the second transport path 25 by the third paper feed unit 32 and the third transport unit 33. The recording sheet in the fourth cassette 41 in the fourth paper feed unit 40 passes through the second transport path 25 by the fourth paper feed unit 42, the fourth transport unit 43, and the fifth transport unit 45. It is transported to the second transport unit 23. Each recording sheet conveyed to the second conveyance unit 23 is conveyed to the first conveyance unit 13 through the first conveyance path 15, and the first conveyance unit 13 transfers the transfer nip portion N <b> 1 in the image processing unit B. To be transported.

  In the copying machine having such a configuration, the uppermost recording sheet accommodated in the first paper feeding cassette 11 in the first paper feeding unit 10 is fed to the first paper feeding unit 12 by the urging force of the cassette paper feeding stand 11a. When the first cassette side pickup roller 12a is rotated in this state, the uppermost recording sheet is in contact with the first cassette side pickup roller 12a. 12b and the first cassette side separation roller 12c are supplied to the first sheet feeding nip, and only one recording sheet is separated by the rotation of the first cassette side sheet feeding roller 12b and the first cassette side separation roller 12c. Then, it passes through the first sheet feeding nip obliquely upward to the right. The leading end portion of the recording sheet that has passed through the first sheet feeding nip is disposed in the vicinity of the upper portion of the first cassette side separation roller 12c on the downstream side in the conveyance direction, and the cassette side first conveyance guide 12f and the cassette side second conveyance guide. It is guided upward by 12h. Thereafter, the leading end of the recording sheet comes into contact with a flexible guide 12k provided continuously above the cassette-side second conveyance guide 12h, and the first conveyance driven roller 13b and the first conveyance guide roller 13b are contacted by the flexible guide 12k. 1 is introduced into a conveyance nip which is a pressure contact portion with the conveyance driving roller 13a. The recording sheet introduced into the conveyance nip passes through the conveyance nip by the rotation of the first conveyance driving roller 13a and the first conveyance driven roller 13b, and is conveyed to the image processing unit B above the first conveyance unit 13, where the image is printed. A toner image is formed in the process part B.

  In such a copying machine, when the printing operation is continuously performed on a plurality of recording sheets accommodated in the first paper feed cassette 11, the uppermost recording in the first paper feed cassette 11 is performed. The sheet passes through the first sheet feeding nip between the first cassette side sheet feeding roller 12b and the first cassette side separation roller 12c, and passes through the conveyance nip which is a pressure contact portion with the first conveyance driving roller 13a in the conveyance unit 13. Then, when the recording sheet is conveyed to the registration roller 66, the leading end of the recording sheet to be conveyed next is introduced into the first sheet feeding nip, and the leading end of the recording sheet is sandwiched between the first sheet feeding nips. The standby state extends from the first sheet feeding nip over about 2 to 3 mm. In this case, the recording sheet having the leading end sandwiched between the first sheet feeding nips is in pressure contact with the first pickup roller 12a inside the first sheet feeding cassette 11, and each side edge in the width direction is side-regulated. The state is regulated by the plate 11d. Thereafter, the preceding recording sheet is conveyed to the image processing section B by the registration roller 66 at a predetermined timing, so that the succeeding recording sheet with the leading end sandwiched between the first sheet feeding nips becomes the first cassette side sheet feeding roller. 12 b and the first cassette side separation roller 12 c are rotated to the registration roller 66 through the conveyance nip of the first conveyance unit 13.

  As described above, when a print job is interrupted due to a trouble such as a paper jam other than in the first paper feeding unit in a standby state where the leading end is sandwiched between the first paper feeding nips, the user can In order to replenish the recording sheet in one sheet feeding cassette 11 or to replace the recording sheet with a different size, the first sheet feeding cassette 11 may be pulled out from the apparatus main body by the user. In this case, when the first paper feed cassette 11 is pulled out from the apparatus main body, the release rib 11c provided on the first paper feed cassette 11 contacts the operation lever 12n provided on the first paper feed unit 12, When the operation lever 12n is sequentially pushed downward and the first paper feed cassette 11 is pulled out over, for example, 11.6 mm, the first cassette side separation roller 12c is moved to the first cassette side as shown in FIG. 5B. For example, it is separated from the paper supply roller 12b by 1.9 mm. As a result, the front end portion of the recording sheet located at the first paper feed nip is released from the pressure contact state by the first cassette side paper feed roller 12b and the first cassette side separation roller 12c and can move together with the first paper feed cassette 11. It becomes a state.

  In such a state, when the first paper feed cassette 11 is further pulled out from the apparatus main body, the uppermost recording sheet in the first paper feed cassette 11 whose leading end is located at the first paper feed nip is transferred to the first paper feed cassette 11. Since the side edges on both sides in the width direction are regulated by the side regulating plates 11 d of the paper cassette 11, the paper cassette 11 moves together with the first paper feeding cassette 11. As a result, the leading edge of the recording sheet is slid in the pulling direction along the first cassette-side paper feed roller 12b and the first cassette-side separation roller 12c, and the leading edge of the recording sheet located on the pulling-direction side is The side edge portion is introduced between the lower guide portion 17b and the upper guide portion 17e of the first sheet guide member 17 through the first cutout portion 10d provided in the first side plate 10a. Thereafter, when the first sheet feeding cassette 11 is further pulled out from the apparatus main body, the side edge portion on the pulling direction side at the leading end portion of the recording sheet introduced between the lower guide portion 17b and the upper guide portion 17e is The side guide portion 17c is in contact with the side guide portion 17c that is inclined with respect to the feeding direction. Due to the side guide portion 17c, a component of force acting in a direction opposite to the feeding direction acts on the recording sheet, and the movement in the drawing direction is accompanied. The recording sheets are sequentially guided upstream in the feeding direction. As a result, the entire recording sheet is moved to the upstream side in the feeding direction and moved into the first paper feed cassette 11 that has been pulled out, and between the pair of side regulating plates 11d in the first paper feed cassette 11. It will be in the state accommodated in the predetermined position. In this state, when the first paper feeding cassette 11 is further pulled out from the apparatus main body, the release rib 11c releases the contact state with the operation lever 12n, and the first cassette side separation roller 12c is fed to the first cassette side. The state is pressed against the paper roller 12b.

  In this case, the end portion of the side guide portion 17c of the first sheet guide member 17 on the drawing direction side is upstream of the front side housing frame 16 disposed on the drawing direction side of the first sheet cassette 11 in the feeding direction. Therefore, the leading edge of the recording sheet is guided to the upstream side in the feeding direction from the front housing frame 16 by the side guide portion 17c, and there is no possibility of being caught by the front housing frame 16. In addition, since it is not necessary to provide the front housing frame 16 with a notch that allows the leading end of the recording sheet to pass therethrough, the front housing frame 16 that is required to have high strength in the apparatus main body has the strength. The strength is maintained without lowering.

As described above, the recording sheet in which the leading end is sandwiched between the first cassette-side paper feed roller 12b and the first cassette-side separation roller 12c is pulled out without being damaged. Housed in a paper cassette 11. In the present embodiment, the downstream end of the first cutout portion 10d formed in the first side plate 10a is 17 mm or more along the downstream side of the recording sheet feeding direction from the first sheet feeding nip. Since the end of the side guide portion 17c of the first sheet guide member 17 on the opposite side to the pulling direction is located at a position corresponding to the end portion on the side in the feeding direction, Even if the leading end portion of the recording sheet sandwiched between the first sheet feeding nips is displaced to the downstream side in the feeding direction from the first sheet feeding nip due to vibration of the first sheet feeding cassette 11, the side guide portion 17c. Abuts securely. Furthermore, since it is an inclined angle of more than 55 ° to a straight line extending in the direction downstream side feeding is the side guide portion 17c, waist relatively strong 157g ^{/ m 2} ~210g ^/ m 2 about a cardboard Even if it exists, it can be reliably accommodated in the first paper feed cassette 11 without being bent in the first paper feed cassette 11.

In the copying machine of the present embodiment, as the recording sheet, the weight per unit area (basis weight) of, 64 g / ^{m 2} plain paper, 80 g / ^{m 2} recycled ^paper, of 157g / ^{m 2} ~210g / m 2 cardboard for four of cardboard ^{210g / m 2 ~256g / m 2} , respectively, the experiment was contained in the first sheet cassette 11 pulled out of the first paper feed cassette 11 in the middle to have performed continuous printing performed As a result, all the recording sheets could be smoothly returned to the predetermined accommodation state in the first paper feed cassette 11 by the first sheet guide member 17. For comparison, when the inclination angle of the side guide portion 17c in the first sheet guide member 17 is 45 ° or less and the end of the first cutout portion 10d formed on the first side plate 10a on the downstream side in the feeding direction. The portion is set to a distance of 15 mm or less along the downstream side in the feeding direction with respect to the first sheet feeding nip, and the side guide portion 17c in the first sheet cassette 17 is pulled out at a position corresponding to the end on the downstream side in the feeding direction. When the same experiment was performed on the above four types of recording sheets for each of the case where the end opposite to the direction was positioned, the inclination angle of the side guide portion 17c in the first sheet guide member 17 was determined. If the angle is 45 ° or less, any of the four types of recording sheets may not be smoothly returned to the predetermined accommodation state in the first paper feed cassette 11. It was. Therefore, it is preferable that the inclination angle of the side guide portion 17c with respect to the straight line extending upstream in the extending direction is 55 ° or more. Further, an end portion of the feeding direction downstream side of the first cut-out portion 10d, when the following distance 15mm from the sheet feed nip, basis weight with respect to cardboard ^{157g / m 2 ~210g / m 2} , the first In some cases, the paper cassette 11 cannot be smoothly returned to the predetermined accommodation state. This, although the basis weight is cardboard 157g ^{/ m 2} ~210g ^/ m 2 is relatively lower back is ^strong, because the waist is not strong enough cardboard ^{210g / m 2 ~256g / m 2} , the first feed This is because the side edges on both sides are regulated by the side regulating plate 11d in the cassette 11 and may be bent in the first paper feeding cassette 11. Accordingly, the position of the upstream end portion of the first cutout portion 10d in the feeding direction, that is, the end portion of the side guide portion 17c of the first sheet guide member 17 opposite to the pulling direction is fed out from the sheet feeding nip. It is preferable to arrange a distance of 17 mm or more along the downstream side. The above experimental results are shown in the table of FIG.

  In the copying machine according to the present embodiment, the second paper feeding unit 20 has the same configuration as the first paper feeding unit 10, and thus the second paper feeding unit 10 has the same configuration as the first paper feeding unit 10. Even if the second sheet feeding cassette 21 is pulled out from the apparatus main body with the leading end of the recording sheet sandwiched between the sheet feeding nips with respect to the recording sheet stored in the sheet cassette 21, the recording sheet is not damaged. The second paper cassette 21 can be smoothly returned to the predetermined accommodation state.

  In the copying machine of the present embodiment, the recording sheet fed from the first paper feed cassette 11 is fed to the first cassette side paper feed nip between the first cassette side paper feed roller 12b and the first cassette side separation roller 12c. In this case, for example, when the leading end is clogged with extending from the first cassette side paper feed nip over 10 mm or more, the manual feed unit 14 is separated from the first paper feed unit 12 as in the case of the conventional copying machine. As shown in FIG. 4, the first paper feed unit cover 12d may be rotated about the first support pin 12e. As a result, since the first cassette side paper feed roller 12b and the first cassette side separation roller 12c are exposed to the outside of the apparatus main body, the recording sheet jammed in the first cassette side paper feed nip can be easily removed. Can do.

  In the above description, the sheet feeding nip is formed by pressing the sheet feeding roller and the separation roller. However, the present invention is not limited to such a configuration. For example, instead of the sheet feeding roller, a sheet feeding belt is used. As described above, a sheet feeding rotating body whose outer peripheral surface moves around may be used. In addition, the separation member is not limited to a structure that rotates while being pressed against the sheet feeding rotator, but may be a separation member that is pressed against the sheet feeding rotator to separate the recording sheets.

  Furthermore, the image forming apparatus according to the present invention is not limited to a tandem type color digital copying machine. For example, four developing devices are arranged around a rotation shaft, and these four developing devices are sequentially arranged in an electrostatic latent image. It may be a so-called four-cycle image forming apparatus that forms a full-color image facing the image carrier, a monochrome image forming apparatus that includes only one developing device, or the like. Further, the sheet supply mechanism of the present invention is not limited to a copying machine but can be applied to a printer, a FAX, an MFP (Multiple Function Peripheral), and the like.

  In the present invention, after a recording sheet in a paper feeding cassette is supplied to a paper feeding nip between a paper feeding roller and a separation roller pressed against each other by a pickup roller, the recording sheet is rotated in a predetermined direction by the rotation of the paper feeding roller and the separation roller. In the paper feeding unit that transports the paper, the recording sheet in the paper feeding cassette can be prevented from being damaged when the paper feeding cassette is pulled out from the apparatus body.

1 is a schematic front view for explaining an internal configuration of a tandem color digital copying machine which is an example of an image forming apparatus according to the present invention. FIG. 3 is a cross-sectional view showing a specific configuration of a first paper feed unit provided in the copier. It is sectional drawing which expands and shows the right side part and its peripheral part of a 1st paper feed part. It is operation | movement explanatory drawing of the cassette side conveyance guide provided in the 1st paper feed part. (A) is sectional drawing for demonstrating the structure of the 1st sheet feeding unit vicinity in the 1st sheet feeding unit provided in the 1st sheet feeding part, (b) is the operation | movement explanatory drawing. (A) and (b) are side views of the first paper feed cassette shown together with a part on the apparatus main body side for explaining the operation by the pressure release mechanism when the first paper feed cassette is pulled out from the apparatus main body. is there. FIG. 3 is a plan view of the first paper feed cassette in a state where the first paper feed cassette is mounted on the apparatus main body. It is a top view of the front side part of a sheet supply mechanism. It is a perspective view of the front side part of a sheet supply mechanism. FIG. 6 is a perspective view of a first sheet feeding unit and a second sheet feeding unit of a sheet supply mechanism. FIG. 6 is a front view of a first sheet feeding unit and a second sheet feeding unit of the sheet supply mechanism. (A) is the perspective view which shows the state which looked at the state which removed the sheet guide member attached to the side-plate main-body part from the unwinding direction of the 1st paper feed cassette, (b) is the direction from the opposite side It is the perspective view of the state seen. In the copying machine of this embodiment, a table showing results of an experiment in which the first sheet cassette is pulled out while four types of recording sheets are stored in the first sheet cassette and continuous printing is being performed. It is.

Explanation of symbols

A sheet supply mechanism B image processing unit C image reading unit 10 first sheet feeding unit 10a first side plate 10b side plate body unit 10c side plate sheet feeding side unit 10d first notch unit 11 first sheet feeding cassette 11a cassette sheet feeding table 11b Right side surface 11c Release rib 11d Side regulating plate 12 First paper feed unit 12a First cassette side pickup roller 12b First cassette side paper feed roller 12c First cassette side separation roller 12d First paper feed unit cover 12e First support pin 12f Cassette side first transport guide 12g Second support pin 12h Cassette side second transport guide 12k Flexible guide 12m Separating roller support frame 12n Operation lever 12p Push spring 13 First transport unit 13a First transport drive roller 13b First transport driven Roller 14 Manual feed unit 14a Manual feed 14b Manual feed roller 14f Manual feed roller 14g Manual feed roller 15 First transport path 16 Front side housing frame 17 First sheet guide member 17a Bracket part 17b Lower guide part 17c Side guide portion 17e Upper guide portion 20 Second paper feed portion 20a Second front cover 20d Second notch portion 21 Second paper feed cassette 22 Second paper feed unit 23 Second transport unit 27 Second sheet guide member 30 3rd paper feed section 31 3rd paper feed cassette 32 3rd paper feed unit 33 3rd transport unit 40 4th paper feed section 41 4th paper feed cassette 42 4th paper feed unit 43 4th transport unit 44 5th transport unit 51 Intermediate transfer belt 52Y, 52M, 52C, 52K The image forming unit 53 exposure device 58 secondary transfer roller 59 fixing unit

Claims (11)

An image processing unit for forming an image on a recording sheet;
An image forming apparatus comprising: a sheet feeding unit that supplies a recording sheet to the image processing unit;
The paper feeder is
A paper feed cassette that can be pulled out from the apparatus main body provided with the image process unit, and that contains recording sheets therein;
A pickup roller that feeds a recording sheet in the paper feed cassette in a direction orthogonal to a pulling direction of the paper feed cassette; a paper feed rotating body that forms a paper feed nip by being pressed against each other; and a separation member. Then, while the recording sheet fed by the pickup roller passes through the sheet feeding nip by the outer circumferential surface of the sheet feeding rotating body, the recording sheet is separated one by one and fed toward the image processing unit. Paper feeding means,
A pressure release means for releasing the pressure contact between the paper feed rotating body and the separation member as the paper feed cassette is pulled out from the apparatus main body;
An image forming apparatus comprising: When the recording sheet having the leading end located in the sheet feeding nip moves together with the sheet feeding cassette pulled out from the apparatus main body, the apparatus contacts the side edge of the leading end of the recording sheet on the drawing direction side. A sheet guide member provided on the main body;
The image forming apparatus according to claim 1, wherein the sheet guide member guides the recording sheet to be contacted in a direction opposite to a feeding direction by the pickup roller in accordance with the movement in the drawing direction.   3. The sheet guide member according to claim 2, wherein the sheet guide member guides the leading end portion of the recording sheet at an inclination angle of 55 ° or more in the drawing direction with respect to a direction opposite to a feeding direction by the pickup roller. Image forming apparatus.   3. A cutout portion through which a front end portion of a recording sheet that contacts the sheet guide member passes is formed in a side plate that supports the separation member on the drawing direction side of the apparatus main body. The image forming apparatus according to 3.   5. The image forming apparatus according to claim 4, wherein the cutout portion is formed along a feeding direction of the pickup roller, and has a length of 17 mm or more from the paper feeding nip in the feeding direction. . In the apparatus main body, a front-side housing frame is arranged on the sheet guide member on the drawing direction side of the sheet feeding cassette,
The image forming apparatus according to claim 2, wherein the sheet guide member moves a leading end portion of the recording sheet to a position where the sheet guide member does not contact the front housing frame.   7. The sheet feeding cassette according to claim 1, further comprising a side regulating member that regulates side edges on both sides in the drawing direction and opposite directions of the recording sheet accommodated therein. The image forming apparatus described. The pressure release means is
A frame that rotatably supports the separating member in a direction away from the sheet feeding rotating body;
A release member that is provided in the paper feed cassette and releases the pressure contact by separating the separation member from the paper feed rotating body by contacting the frame as the paper feed cassette is pulled out from the apparatus main body. When,
The image forming apparatus according to claim 1, further comprising:   The image forming apparatus according to claim 8, wherein the release member is in contact with the frame over a predetermined length along a pull-out direction of the paper feed cassette.   The sheet feeding means includes a cover member that covers the sheet feeding rotator and the separating member on the downstream side in the recording sheet conveyance direction by the sheet feeding rotator and the separating member. The image forming apparatus according to claim 1, wherein the image forming apparatus is movable so as to be exposed to the outside.   The image forming apparatus according to claim 1, wherein two sets of the sheet feeding units are provided, and the two sets of sheet feeding units are arranged side by side in the vertical direction.

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