JP6566337B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus for separating sheet over bets, the one by a separation nip with the feeding Okukarada and minutes isolates abuts.

  Conventionally, as this type of image forming apparatus, the one described in Patent Document 1 is known. FIG. 29 is a configuration diagram showing a paper feed cassette in the image forming apparatus described in Patent Document 1. In the drawing, a sheet feeding cassette 970 that stores a plurality of recording sheets S in a bundle of sheets is taken in and out along a direction perpendicular to the paper surface of the drawing with respect to an image forming apparatus main body (not shown). is there. In the vicinity of the paper feed cassette 970, a paper feed roller 981 held by the image forming apparatus main body is disposed. The leading end of the sheet bundle accommodated in the paper feed cassette 970 is urged upward by the movable bottom plate 971 of the paper feed cassette 970, and is brought into pressure contact with the paper feed roller 981. At the side of the pressure contact region, the paper feed roller 981 and the separation roller 982 are in contact with each other to form a separation nip. When the paper feed roller 981 is driven to rotate, the uppermost recording sheet S of the sheet bundle is sent out from the paper feed cassette 970 toward the separation nip. At this time, not only the uppermost recording sheet S but also a phenomenon called double feeding in which the recording sheet S below the uppermost recording sheet S is fed out from the paper feed tray 970 may occur. . When a plurality of recording sheets S are overlapped and overlapped by the separation nip, the uppermost recording sheet S that is in direct contact with the sheet feeding roller 981 is fed. The sheet is conveyed in the sheet feeding direction following the surface movement of the paper roller 981. On the other hand, other recording sheets are fed back toward the paper feed cassette 970 following the separation roller 982 whose surface moves in the reverse direction to the paper feed roller 981 in the separation nip. By this feeding back, even if double feeding occurs, only the recording sheet S that is in direct contact with the paper feed roller 981 is separated into one sheet. Then, it is sent to an image forming apparatus (not shown).

  The means for feeding the recording sheet in the paper feed cassette toward the separation nip is generally performed by a pickup roller provided separately from the paper feed roller and the separation roller. However, in the image forming apparatus described in Patent Document 1, the paper feed roller 981 plays a role without providing a pickup roller. In such a configuration (hereinafter referred to as a pickup-less system), it is possible to reduce the cost by omitting the attachment of the pickup roller.

  However, the pickupless system has a problem that it becomes easy to crease the recording sheet at the separation nip when a thin sheet or the like is used as the recording sheet. Specifically, as shown in FIG. 30, in the pickupless system in which the peripheral surface of the sheet feeding roller 981 is in contact with both the leading end portion of the sheet bundle and the separation roller 982, the leading end portion of the sheet bundle and the separation nip are separated. And the distance will be very close. When the leading end portion of the recording sheet S sent out from the paper feed cassette as the paper feed roller 981 is rotated passes through the pressure contact portion between the movable bottom plate 971 and the paper feed roller 981, the paper feed roller 981 It is transported in a slightly floating state without being closely attached to the curved surface. As a result, the front end often abuts against the peripheral surface of the separation roller 982 before entering the separation nip without entering the separation nip straight. In the recording sheet S having a low waist, when the leading end abuts against the peripheral surface of the separation roller 982, as shown in FIG. 31, a corrugation that undulates in the direction perpendicular to the conveying direction is formed at the leading end. The undulation is sandwiched in the separation nip as it is, so that the recording sheet S is creased. Even if a guide member that guides the leading end portion of the recording sheet S fed from the sheet feeding cassette toward the separation nip is provided, the same crease is given to the recording sheet that is weak. This is because a recording sheet having a low waist hits the leading end of the recording sheet against the guide member to form a corrugated portion.

  Therefore, the present inventors are developing a new image forming apparatus as follows. That is, in this image forming apparatus, as shown in FIG. 32, a deflection applying body 985 for applying a deflection to the recording sheet S is provided before the separation nip. The deflection imparting body 985 is disposed so as to contact the recording sheet S immediately before entering the separation nip from below in the direction of gravity. The deflection imparting body 985 contacts the partial area of the recording sheet S from below in the direction of gravity, so that the recording sheet S having a low waist is partially bent as shown in the drawing direction. Generate wrinkles along the direction of the arrow in the figure. By forming such a bend, it is difficult for the recording sheet S to bend in a direction orthogonal to the bend, and the undulation of the recording sheet S shown in FIG. 31 is hindered. Thereby, it is possible to suppress the occurrence of folds in the recording sheet S that is weak at the separation nip. Note that the paper feed roller 981 and the separation roller 982 shown in FIG. 31 are both short rollers that abut only on the area between the two ridges formed on the recording sheet S by the two deflection imparting bodies 985 in FIG. It consists of For this reason, the two scissors are not sandwiched between the separation nips and creased.

  In the image forming apparatus having such a configuration, when a stiff recording sheet S such as cardboard is used, the present inventors have found that the recording sheet S sent out from the sheet feeding cassette is stagnated at the separation nip or its periphery. It was found by experiment that it becomes easy to generate the phenomenon called. The non-delivery occurred for the reason described below. That is, as shown in FIG. 33, one of the two deflection imparting bodies 985 is present at a position shifted to one end side in the roller axial direction from the roller portions of the paper feed roller 981 and the separation roller 982. Further, the other deflection imparting body 985 is present at a position shifted from the roller portion toward the other end side in the roller axial direction. Then, in order to generate a relatively large wrinkle as shown in FIG. 32, each leading end protrudes greatly upward from the conveyance path of the recording sheet S indicated by an arrow in FIG. . By such two deflection imparting bodies 985, both ends of the recording sheet S in the width direction (direction perpendicular to the conveyance direction) are lifted up largely before the separation nip, so that the central portion in the width direction of the recording sheet S is formed. It strongly presses against the area immediately before the separation nip entry on the peripheral surface of the paper feed roller 981. As a result, a large conveyance resistance is applied to the recording sheet S and the recording sheet S is slipped on the surface of the paper feed roller 981, so that the recording sheet S cannot be fed in the conveyance direction and non-feeding occurs. It will let you.

The present invention has been made in consideration of the above background, it is an object while suppressing the occurrence of weak stone over preparative folds waist, not feeding waist strong stone over preparative generation that is to provide the images forming apparatus that can have suppressed.

In order to achieve the above object, the present invention separates a sheet that is in direct contact with the feeding body from a sheet other than the sheet that is in direct contact with a separation nip where the feeding body and the separating body abut. In the image forming apparatus including the separation feeding unit that feeds the sheet, the leading end of the bending imparting portion that contacts the sheet from below at the upstream side of the separation nip in the sheet conveying direction is formed, and rises from below to above. the flexible tip forming member with the parts and the tip extending portion, the distal end extension is not fixed to another member, the surface of the face and the downstream side in the sheet conveyance direction upstream side of the rising portion Each of the leading end extending portions can be bent by fixing each of the fixing target members to the fixing target member, and outside the end opposite to the separation nip of the leading end extending portion in the width direction orthogonal to the sheet conveying direction. And a position on the downstream side of the distal end extension in the sheet conveyance direction and is characterized in that a convex portion of contact tip from below the sheet.

According to the present invention, the images forming apparatus, while suppressing the occurrence of weak stone over preparative folds waist, there is an excellent effect that it is possible to suppress the occurrence of non-feeding waist strong stone over preparative .

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 2 is an enlarged configuration diagram illustrating an enlarged photoconductor and a surrounding configuration in the printer. FIG. 3 is a partially enlarged view showing a partially enlarged lower region of the printer. FIG. 2 is a partially enlarged view partially showing a paper feeding cassette being pulled out from the inside of the main body casing of the printer. FIG. 6 is a perspective view partially showing the main body housing in a state where a space is generated inside by removal of the paper feeding cassette. The perspective view which shows the paper feed cassette partially from the back. FIG. 4 is a partial perspective view partially showing a front side of the sheet feeding cassette. The disassembled perspective view which shows the separation roller unit of the paper feed cassette. FIG. 4 is a partial perspective view partially showing a front end portion of the sheet feeding cassette. FIG. 6 is a partial perspective view partially showing a separation roller unit of the paper feed cassette mounted in the main body casing and a feeding roller fixed in the main body casing. The longitudinal cross-sectional view which shows the longitudinal cross-section of the feed roller and the separation roller unit. The longitudinal cross-sectional view which shows the same longitudinal cross-section of the state which pinched | interposed the recording sheet | seat with strong waist in the separation nip. The perspective view which shows the guide unit board of the printer with a recording sheet. The expansion perspective view which expands and shows the bending | flexion provision part of the same guide unit board. The expansion perspective view which shows the same bending | flexion provision part of the state which bent the front-end | tip part. FIG. 3 is an enlarged configuration diagram illustrating the separation nip of the printer and the surrounding configuration in an enlarged manner. The disassembled perspective view which expands and shows the same bending | flexion provision part to which the code | symbol which paid its attention was attached | subjected to each part. The disassembled perspective view which expands and shows the bending | flexion provision part to which the code | symbol which paid its attention to material was attached | subjected to each part. The side view which shows the same guide unit board. FIG. 6 is a perspective view showing a recording sheet curled in a paper feed cassette. FIG. 3 is a perspective view showing a paper feed cassette and a feed roller unit case of the printer. The perspective view which shows a part of the paper feed cassette from diagonally upward. FIG. 3 is an explanatory diagram for explaining a state of a recording sheet in a paper feeding cassette not provided with a curl correction body. FIG. 3 is an explanatory diagram for explaining a state of a recording sheet in a paper feeding cassette provided with a curl correction body. The perspective view which shows the paper feed cassette with which a curl correction body is attached or detached. FIG. 6 is an enlarged perspective view of the paper feed cassette for explaining the sliding movement of the curl correction body held on the movable bottom plate of the paper feed cassette. The front view which shows the same curl correction body. The perspective view which shows the modification of the curl correction body with the movable baseplate of a paper feed cassette. FIG. 9 is a configuration diagram showing a paper feed cassette in the image forming apparatus described in Patent Document 1. FIG. 3 is an explanatory diagram for explaining a state of a recording sheet that has started to be sent out from the paper feeding cassette. 4 is an explanatory diagram for explaining undulations caused by a recording sheet having a low waist around a separation nip. FIG. The perspective view for demonstrating the bending and wrinkle which are provided to a recording sheet by the bending provision body. FIG. 6 is a perspective view showing a paper feed roller, a separation roller, and a deflection imparting body in an image forming apparatus under development. FIG. 3 is a perspective view illustrating a main part of a feeding roller of the printer. The side view which shows the principal part of the roller made as an experiment by the present inventors. FIG. 3 is a side view showing a feeding roller of the printer. The enlarged block diagram which expands and shows the weight fixed to the feed roller. The partial side view which expands and shows partially the rib partition space of the feed roller. The side view which shows the feed roller of the printer which concerns on a modification.

  Hereinafter, as an image forming apparatus to which the present invention is applied, an electrophotographic printer (hereinafter simply referred to as a printer) that forms an image by an electrophotographic method will be described. The present invention is not limited to an image forming apparatus that forms an image by an electrophotographic method, and an image that forms an image by another method such as an ink jet method or a toner projection method described in JP-A-2002-307737. The present invention can also be applied to a forming apparatus.

  First, a basic configuration of the printer according to the embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating a printer according to an embodiment. In this figure, the printer includes a photosensitive member 1 as a latent image carrier, a sheet feeding cassette 100 as a sheet storage unit configured to be detachable from a main body housing 50, and the like. A plurality of recording sheets S are accommodated in a sheet bundle inside the sheet feeding cassette 100.

  The recording sheet S in the paper feed cassette 100 is sent out from the cassette by the rotational drive of a feed roller 35 described later, and reaches the paper feed path 42 after passing through a separation nip described later. Thereafter, the sheet is sandwiched between the conveyance nips of the first conveyance roller pair 41 and conveyed in the sheet feeding path 42 from the upstream side to the downstream side in the conveyance direction. A registration roller pair 49 is disposed near the end of the paper feed path 42. Conveyance of the recording sheet S is temporarily stopped in a state in which the leading end abuts against the registration nip of the registration roller pair 49. At the time of the abutting, the skew of the recording sheet S is corrected.

  The registration roller pair 49 starts rotational driving at a timing at which the recording sheet S can be superimposed on a toner image on the surface of the photoreceptor 1 at a transfer nip described later, and sends the recording sheet S toward the transfer nip. At this time, the first conveyance roller pair 41 starts to rotate at the same time, and the conveyance of the recording sheet S that has been temporarily stopped is resumed.

  The main body of the printer has a manual paper feed unit including a manual feed tray 43, a manual feed roller 44, a separation pad 45, and the like. The recording sheet manually fed to the manual feed tray 43 of the manual paper feed unit is sent out from the manual feed tray 43 by the rotational drive of the manual feed roller 44. Then, after passing through a separation nip due to the contact between the manual feed roller 44 and the separation pad 45, the paper feed path 42 enters a region upstream of the registration roller pair 49. Thereafter, similarly to the recording sheet S sent out from the paper feed cassette 100, after passing through the registration roller pair 49, it is sent to a transfer nip described later.

  FIG. 2 is an enlarged configuration diagram showing the photoreceptor 1 and the surrounding configuration in the printer in an enlarged manner. Around the drum-shaped photoreceptor 1 that is driven to rotate counterclockwise in the drawing, there are a recovery screw 3, a cleaning blade 2, a charging roller 4, a latent image writing device 7, a developing device 8, a transfer roller 10, and the like. It is arranged. The charging roller 4 having a conductive rubber roller portion rotates while contacting the photoconductor 1 to form a charging nip. A charging bias output from a power source (not shown) is applied to the charging roller 4. As a result, discharge occurs between the surface of the photoreceptor 1 and the surface of the charging roller 4 at the charging nip, so that the surface of the photoreceptor 1 is uniformly charged.

  The latent image writing device 7 includes an LED array, and performs light scanning with LED light on the uniformly charged surface of the photoreceptor 1. Of the uniformly charged background portion of the photoconductor 1, the region irradiated with light by this optical scanning attenuates the potential. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 1.

  The electrostatic latent image passes through the developing area facing the developing device 8 as the photosensitive member 1 is rotated. The developing device 8 includes a circulation conveyance unit and a development unit, and the circulation conveyance unit contains a developer containing toner and a magnetic carrier. The circulation conveyance unit includes a first screw 8b that conveys the developer to be supplied to the developing roller 8a, which will be described later, and a second screw 8c that conveys the developer in an independent space located directly below the first screw 8b. doing. Furthermore, it also has an inclined screw 8d for delivering the developer from the second screw 8c to the first screw 8b. The developing roller 8a, the first screw 8b, and the second screw 8c are arranged in a parallel posture. On the other hand, the inclined screw 8d is disposed in a posture inclined from them.

  The first screw 8b conveys the developer from the back side to the near side in the direction orthogonal to the paper surface of the drawing in accordance with the rotation of the first screw 8b. At this time, a part of the developer is supplied to the developing roller 8a disposed to face the developing roller 8a. The developer transported by the first screw 8b to the vicinity of the end on the near side in the direction orthogonal to the paper surface of the drawing is dropped onto the second screw 8c.

  While receiving the used developer from the developing roller 8a, the second screw 8c conveys the received developer from the back side to the near side in the direction orthogonal to the paper surface of the drawing as it rotates. . The developer transported to the vicinity of the end on the near side in the direction orthogonal to the paper surface of the drawing by the second screw 8c is delivered to the inclined screw 8d. Then, along with the rotational drive of the inclined screw 8d, after being conveyed from the near side to the far side in the direction orthogonal to the paper surface of the figure, near the end on the far side in the same direction, the first screw 8b Delivered.

  The developing roller 8a includes a rotatable developing sleeve made of a cylindrical nonmagnetic member, and a magnet roller fixed in the sleeve so as not to rotate around the developing sleeve. A part of the developer conveyed by the first screw 8b is pumped up on the surface of the developing sleeve by the magnetic force generated by the magnet roller. When the developer carried on the surface of the developing sleeve passes along the position where the sleeve and the doctor grade are opposed to each other along the surface of the developing sleeve, the layer thickness thereof is regulated. After that, in the development area facing the photoconductor 1, it moves while rubbing against the surface of the photoconductor 1.

  A developing bias having the same polarity as the toner or the background potential of the photoreceptor 1 is applied to the developing sleeve. The absolute value of the developing bias is larger than the absolute value of the latent image potential and smaller than the absolute value of the background portion potential. For this reason, in the development area, a development potential for electrostatically moving the toner from the sleeve side to the latent image side acts between the electrostatic latent image on the photoreceptor 1 and the development sleeve. On the other hand, a background potential that electrostatically moves toner from the background portion side to the sleeve side acts between the background portion of the photoreceptor 1 and the developing sleeve. As a result, in the development area, the toner selectively adheres to the electrostatic latent image on the photoreceptor 1 and the electrostatic latent image is developed.

  The developer that has passed through the developing area enters the area where the sleeve and the second screw 8c face each other as the developing sleeve rotates. In the facing region, a repulsive magnetic field is formed by two magnetic poles having different polarities from among the plurality of magnetic poles provided in the magnet roller. The developer that has entered the facing region separates from the surface of the developing sleeve due to the action of the repulsive magnetic field and is collected on the second screw 8c.

  The developer conveyed by the inclined screw 8d contains the developer collected from the developing roller 8a, and the developer contributes to development in the development area, so that the toner density is lowered. The developing device 8 includes a toner concentration sensor (not shown) that detects the toner concentration of the developer conveyed by the inclined screw 8b. The control unit 51 outputs a replenishment operation signal for replenishing toner to the developer conveyed by the inclined screw 8b as necessary based on the detection result by the toner density sensor.

  A toner cartridge 9 is disposed above the developing device 8. The toner cartridge 9 agitates the toner contained therein by an agitator 9b fixed to the rotary shaft member 9a. Then, the toner replenishing member 9c is rotationally driven in accordance with a replenishment operation signal output from the control unit 51, so that an amount of toner corresponding to the rotational drive amount is replenished to the inclined screw 8b of the developing device 8.

  The toner image formed on the photoconductor 1 by development enters the transfer nip where the photoconductor 1 and the transfer roller 10 serving as a transfer unit come into contact with the rotation of the photoconductor 1. A charging bias having a polarity opposite to the latent image potential of the photoreceptor 1 is applied to the transfer roller 10, thereby forming a transfer electric field in the transfer nip.

  As described above, the registration roller pair 49 sends the recording sheet S toward the transfer nip at a timing at which the recording sheet S can be superimposed on the toner image on the photoreceptor 1 in the transfer nip. The toner image on the photosensitive member 1 is transferred to the recording sheet S that is brought into close contact with the toner image at the transfer nip by the action of a transfer electric field or nip pressure.

  Untransferred toner that has not been transferred to the recording sheet S adheres to the surface of the photoreceptor 1 after passing through the transfer nip. The transfer residual toner is scraped off from the surface of the photosensitive member 1 by the cleaning blade 2 that is in contact with the photosensitive member 1 and then sent out of the unit casing by the recovery screw 3. The transfer residual toner discharged from the unit casing is sent to a waste toner bottle (not shown) by a transport device (not shown).

  The surface of the photoreceptor 1 cleaned by the cleaning blade 2 is neutralized by a neutralizing means (not shown) and then uniformly charged by the charging roller 4 again. To the charging roller 4 that is in contact with the surface of the photoreceptor 1, foreign substances such as toner additives and toner that cannot be completely removed by the cleaning blade 2 adhere. The foreign matter is transferred to the cleaning roller 5 in contact with the charging roller 4 and then scraped off from the surface of the cleaning roller 5 by the scraper 6 in contact with the cleaning roller 5. The foreign matter scraped off falls onto the recovery screw 3 described above.

  In FIG. 1, the recording sheet S that has passed through the transfer nip where the photosensitive member 1 and the transfer roller 10 abut is sent to the fixing device 44. The fixing device 44 forms a fixing nip by contact between a fixing roller 44a including a heat source such as a halogen lamp and a pressure roller 44b pressed toward the fixing roller 44a. A toner image is fixed on the surface of the recording sheet S sandwiched between the fixing nips by the action of heat or pressure. Thereafter, the recording sheet S that has passed through the fixing device 44 passes through the paper discharge path 45 and is then sandwiched between the paper discharge nips of the paper discharge roller pair 46.

  The printer can be switched between a single-side mode in which an image is formed on only one side of the recording sheet S and a double-side mode in which an image is formed on a good edge of the recording sheet S. In the case of the single-sided mode or in the case of the double-sided mode in which images are already formed on both sides of the recording sheet S, the recording sheet in the paper discharge path 45 is kept by the paper discharge roller pair 46 continuing to rotate forward. S is discharged outside the machine. The discharged recording sheet S is stacked on a stack portion provided on the upper surface of the main body housing 50.

  On the other hand, when the duplex mode is selected and an image is formed only on one side of the recording sheet S, the sheet is discharged when the end of the recording sheet S enters the sheet discharge nip of the sheet discharge roller pair 46. The paper roller pair 46 is driven in reverse. At this time, the switching claw 47 disposed near the end of the paper discharge path 45 is operated to block the paper discharge path 45 and open the entrance of the reverse retransmission path 48. The recording sheet S that has started to reverse by the reverse rotation drive of the paper discharge roller pair 46 is sent into the reverse retransmission path 48. Then, the paper is conveyed while being turned upside down in the reverse retransmission path 48 and then retransmitted to the registration nip of the registration roller pair 49. Thereafter, the toner image is transferred to the other surface at the transfer nip, and then discharged to the outside through the fixing device 44, the paper discharge path 45, and the paper discharge roller pair 46.

  FIG. 3 is a partially enlarged view showing a partially enlarged lower region of the printer. In the sheet feeding cassette 100, a sheet bundle composed of a plurality of recording sheets S is placed on the movable bottom plate 101. The movable bottom plate 101 is urged toward the feeding roller 35 by a bottom plate spring 103. A bottom plate pad 102 made of an elastic member is fixed to the tip of the movable bottom plate 101. The front end of the sheet bundle is pressed toward the feeding roller 35 by the force of the bottom plate spring 103 while being sandwiched between the bottom plate pad 102 and the feeding roller 35.

  When the feeding roller 35 rotates, the uppermost recording sheet S at the top of the sheet bundle is sent out from the movable bottom plate 101. Then, it enters the separation nip due to the contact between the feeding roller 35 and the separation roller 121. As described above, the recording sheet S is pressed against the feeding roller 35 by the pressing means including the movable bottom plate 101, the bottom plate pad 102, the bottom plate spring 103, and the like. The recording sheet S is sent out. In such a configuration, it is possible to reduce the cost by omitting the attachment of the pickup roller to the paper feed cassette 100. In other words, this printer achieves cost reduction by adopting the pickupless system.

  The separation roller 121 is generally applied with a rotational driving force for moving the surface of the separating roller 121 in a direction opposite to that of the feeding roller 35 as necessary. Is not granted. The separation roller 121 rotates only by following the feeding roller 35 and the recording sheet S in the separation nip.

  One end side of the rotation shaft of the separation roller 121 is rotatably supported by a torque limiter (not shown). When the recording sheet S does not enter the separation nip, the separation roller 121 directly contacts the feeding roller 35. When the feeding roller 35 is rotationally driven in this state, a relatively strong driving force is applied from the feeding roller 35 to the separation roller 121. Thereby, the torque limiter allows the driven rotation of the separation roller 121 by the torque of the driven rotation of the separation roller 121 exceeding a predetermined threshold. In other words, when the recording sheet S does not enter the separation nip, the separation roller 121 rotates following the feeding roller 35.

  When only one recording sheet S enters the separation nip, only one recording sheet S is interposed between the separation roller 121 and the feeding roller. When the feeding roller 35 is rotationally driven in this state, a strong conveying force is applied from the feeding roller 35 to the recording sheet S, and the recording sheet S moves in the sheet feeding direction. At the same time, a relatively strong driving force is applied from the feeding roller 35 to the separation roller 121 via the recording sheet S. Thereby, the torque limiter allows the driven rotation of the separation roller 121 by the torque of the driven rotation of the separation roller 121 exceeding a predetermined threshold. That is, even when only one recording sheet S enters the separation nip, the separation roller 121 is driven to rotate.

  On the other hand, it is assumed that a plurality of recording sheets S have entered the separation nip while being overlapped by double feeding. In this case, the uppermost recording sheet S that is in direct contact with the feeding roller 35 at the separation nip is given a relatively strong conveying force by the feeding roller 35, so that the uppermost recording sheet S is a sheet. It is conveyed in the feed direction. Further, the remaining recording sheets excluding the uppermost recording sheet S are given a conveyance resistance by being pressurized in the separation nip. When the conveyance resistance exceeds the frictional resistance between the uppermost recording sheet S and the second recording sheet S, slip occurs between the sheets. As a result of this slip, the torque of the driven rotation of the separation roller 121 falls below a predetermined threshold value, so that the torque limiter does not allow the driven rotation of the separation roller 121. Then, the conveyance resistance for the second and subsequent recording sheets S is further increased, and the movement of the second and subsequent recording sheets S is stopped. In this way, the separation roller 121 separates other recording sheets from the uppermost recording sheet S while imparting conveyance resistance to the plurality of recording sheets S.

  In such a configuration, the recording sheet S is separated at the separation nip without applying the rotational driving force by the motor to the separation roller 121, thereby omitting the drive transmission means for transmitting the drive to the separation roller 121. Cost can be reduced.

  FIG. 4 is a partially enlarged view partially showing the paper feeding cassette 100 being pulled out from the main body housing. As shown in the figure, in this printer, the separation roller 121 is held in the paper feed cassette 100 and is attached to and detached from the main body housing 50 together with the paper feed cassette 100. Thus, the paper feed cassette 100 can be attached to and detached from the main body casing 50 by sliding in the left-right direction in FIG. This is because the separation roller 121 moves together with the paper feed cassette 100, so that the separation roller 121 does not get in the way when the paper feed cassette 100 is slid in the direction of arrow A along the left-right direction in FIG.

  When a jam occurs with the recording sheet S sandwiched in the separation nip, the operator slides the paper feed cassette 100 in the direction of arrow A in the drawing and pulls it out from the main body housing 50. Then, the separation roller 121 is taken out together with the sheet feeding cassette 100 and the separation nip is eliminated. However, the jam sheet is sandwiched between the conveyance nips of the first conveyance roller pair 41 and thus remains in the main body casing 50.

  A space generated in the main body casing 50 by pulling out the paper feed cassette 100 from the main body casing 50 is greatly opened in the direction of arrow A in the drawing, which is the cassette pulling direction. The operator can easily visually recognize the jam sheet from the surface direction through the opening. The jam sheet can be pulled out from the conveyance nip by the first conveyance roller pair 41 while holding both ends of the jam sheet in the roller rotation axis direction with both hands inserted into the opening. At this time, the tensile force is applied to both ends of the jam sheet, so that the concentration of the tensile force is suppressed compared to the case where only one end of the jam sheet is gripped, and the jam sheet is torn. It becomes difficult.

  Therefore, in this printer, it is possible to suppress tearing of the jam sheet during jam processing. In this printer, the paper cassette is pulled out from the main body housing 50 (in the direction of arrow A in the figure) in the direction in which the paper cassette 100 is moved from the sheet storage unit 105 side to the separation roller unit 120 side as shown in the figure. It is.

  FIG. 5 is a perspective view partially showing the main body housing 50 in a state in which a space is created by removing the paper feed cassette (100). The direction of arrow B in the figure is the direction of the rotational axis of the feed roller (35) (not shown). In the figure, only one end side of the main body housing in the same rotational axis direction is shown.

  A rail 53 extending in the attaching / detaching direction of a sheet feeding cassette (not shown) is provided on one end side in the rotational axis direction at the bottom in the main body housing 50. Although not shown in the figure, a similar rail is provided on the other end side in the rotational axis direction. The sheet feeding cassette is attached to and detached from the main body casing 50 by being slid along the rail extending direction while being placed on the rails. Moreover, positioning in the height direction is performed in the main body housing 50 by being placed on the rail.

  In the main body casing 50 shown in the figure, the member extending in the height direction is the right side plate of the main body casing 50. Although not shown in the figure, a left side plate that similarly extends in the height direction is also provided on the other end side in the rotational axis direction. On the inner wall of the right side plate of the main body casing 50, a positioning stopper 51 for positioning the paper feed cassette in the attaching / detaching direction in the main body casing 50 is provided. A similar positioning stopper is also provided on the inner wall of the left side plate (not shown) of the main body housing 50. When the paper feed cassette is placed on the above-described rail and pushed into the inside of the main body housing 50, the paper feed cassette is attached / detached by abutting the abutting portion provided on the paper cassette against the positioning stopper (for example, 51) described above. Directional positioning is made.

  If the abutting portion of the sheet feeding cassette is merely abutted against the positioning stopper, the sheet feeding cassette may be pushed out in the take-out direction when any impact is applied to the main body casing 50. Therefore, a locking member 52 is provided on the inner wall of the right side plate of the main body housing 50 so as to be movable in the same rotational axis direction (arrow B direction). The locking member 52 is restrained at a position protruding from the inner surface of the right side plate of the main body casing 50 to the inside of the casing by being biased by a spring (not shown). The locking member 52 is provided with a taper as illustrated. Although not shown in the figure, a similar locking member 52 is also provided on the inner wall of the left side plate of the main body housing 50.

  FIG. 6 is a perspective view partially showing the paper feed cassette 100 from the rear. On the outer surface of the right side plate of the paper feed cassette 100, a retaining protrusion 106 is projected. The positioning unit 107 provided on the outer surface of the bottom wall of the paper feed cassette 100 is placed on the rail 53 provided in the lower part of the main body housing 50 shown in FIG. Is done. As the paper feed cassette 100 is pushed toward the inside of the main body housing 50 on the rail 53, the retaining projection 106 of the paper feed cassette 100 slides on the taper of the locking member 52 of the main body housing 50. Along with this rubbing, the locking member 52 is pushed toward the outside of the side plate, and the amount of protrusion from the inner surface of the side plate is reduced. Immediately before the paper feed cassette 100 is moved and positioned to a position where the positioning abutment portion 105 abuts against the positioning stopper 51 of the main body housing 50, the retaining projection 106 of the paper feed cassette 100 is attached to the main body housing 50. Separated from the locking member 52. Then, the locking member 52, which has been reduced in the amount of protrusion from the inner surface of the side plate until then, projects at once to the position shown in FIG. 5 by the biasing force of the spring. Then, by bringing the protruding portion into contact with the back surface of the retaining protrusion 106 of the paper feed cassette 100, the paper feed cassette 100 is prevented from moving in the pull-out direction, and the paper feed cassette 100 is restrained to the normal position. As a result, even if a sudden impact is applied to the main body housing 50, the sheet feeding cassette 100 can be normally restrained at the position in the attaching / detaching direction.

  The locking member 52 is also provided with a steep taper on the surface which is not visible on the back side in FIG. With a force of an impact level, the locking member 52 cannot be pushed down by the retaining protrusion 106 of the paper feed cassette 100. However, when the operator pulls out the paper cassette 100 with a certain force, the retaining protrusion 106 of the paper cassette 100 pushes down the locking member 52 while strongly rubbing against the taper on the back side of the locking member 52. Go. Thereby, the operator can pull out the paper feed cassette 100 from the main body housing 50.

  As described above, by positioning the sheet feeding cassette 100 in the height direction and positioning in the attaching / detaching direction, the separation roller (121) held in the sheet feeding cassette 100 is accurately positioned in the main body housing 50. The

  In order to accurately position the paper feed cassette 100 in the height direction, the following configuration may be employed. That is, the positioning stopper (for example, 51) provided on each of the two side plates of the main body housing 50 is formed with a rail portion and a minute protrusion slightly protruding from the surface of the rail portion, and the minute stopper provided on the paper feed cassette 100 is formed. The positioning part is ridden on the minute protrusion. At the same time, the abutting portion (for example, 105) of the sheet feeding cassette 100 is abutted against the abutted portion of the positioning stopper.

  FIG. 7 is a partial perspective view partially showing the front side of the paper feed cassette 100. In the figure, for the sake of convenience, the illustration of the front cover of the paper feed cassette 100 (the cover with a pull handle) is omitted. As shown in the figure, the separation roller 121 is configured as a separation roller unit 120 together with some other components, and is integrally attached to and detached from the mounted portion of the paper feed cassette 100. In this way, by separating the separation roller 121 as a unit, it is possible to reduce the cost by sharing parts with other models. More specifically, the same configuration as the paper feed cassette 100 of this printer is adopted for other types of cassettes having different specifications from the printer. However, since the number of recording sheets S is different from that of the paper feed cassette 100 of this printer, the thickness of the cassette is different. Although the sheet feeding cassettes have different specifications, the separation roller unit 120 has the same specifications. In this way, the parts are shared.

  FIG. 8 is an exploded perspective view showing the separation roller unit 120. A torque limiter 122 is connected to the rotating shaft member 121 a of the separation roller 121. The role of the torque limiter 122 is as described above. The torque limiter 122 and the separation roller 121 are held by a swing holder 123. The side of the torque limiter 122 opposite to the connecting portion with the rotating shaft member 121 a is fixed to the right side plate of the swing holder 123. In addition, the opposite end side of the rotation shaft member a of the separation roller 121 is rotatably supported on the left side plate of the swing holder 123.

  In this way, the swing holder 123 that holds the torque limiter 122 and the separation roller 121 is accommodated in an accommodation member that includes the upper cover 126 and the base cover 124. Specifically, the right and left plates of the swing holder 123 are respectively provided with swing shaft portions 123a that are arranged on the same coaxial line. The swing holder 123 housed in the base cover 124 engages the swing shaft portion with the shaft hole 124 a and the notch 124 b of the base cover 124. Accordingly, the swing holder 123 is supported by the base cover 124 so as to swing around the swing shaft portion 123a.

  The upper cover 126 is fitted to the base cover 124 from above. In this state, the peripheral surface of the separation roller 121 inside the cover is exposed to the outside through the opening 126a provided in the upper cover 126 (see FIG. 7). A coil spring 125 as urging means is fixed to the base cover 124. The coil spring 125 urges the swing holder 123 in the direction from the base cover 124 side toward the upper cover 126 side with the swing shaft portion 123a as the center. When the separation roller unit 120 is not attached to the paper feed cassette 100 as shown in FIG. 7, the peripheral surface of the separation roller 121 abuts against the back surface of the upper cover 126.

  In this printer, the rightmost surface of the main body housing 50 shown in FIG. 1 is the front surface. The leftmost surface in the figure is the back surface. Further, the back end surface of the main body housing 50 in the direction orthogonal to the paper surface of FIG. The front end surface in the same direction is the left side surface. That is, in this printer, the paper feeding cassette 100 mounted in the main body housing 50 is pulled out toward the front of the printer. Further, the paper feed cassette 100 is pushed toward the back of the printer and is mounted in the main body casing 50. Hereinafter, the direction from the rear side to the front side of the printer along the attaching / detaching direction is simply referred to as the front side. The opposite direction is simply referred to as the rear.

  As shown in FIG. 9, when the separation roller unit 120 is mounted on the mounted portion of the paper feed cassette 100, the bottom plate pad 102 fixed to the tip of the movable bottom plate 101 of the paper feed cassette 100 is in the vicinity of the separation roller 121. Located in. As described above, the bottom plate pad 102 presses the recording sheet stored in the sheet feeding cassette 100 toward the feeding roller (35).

  FIG. 10 is a partial perspective view partially showing the separation roller unit 120 of the paper feed cassette 100 mounted in the main body casing and the feeding roller 35 fixed in the main body casing. A feeding roller 35 fixed in the main body casing and a separation roller held in the paper feeding cassette 100 in the process in which the paper feeding cassette 100 is mounted on the main body casing while being slid on the rails of the main body casing. 121 abuts. Specifically, the separation roller 121 before coming into contact with the feeding roller 35 has a part of its peripheral surface more than the upper cover 126 through the opening (126a in FIG. 8) of the upper cover 126 of the separation roller unit 120. It protrudes outside. In this state, the separation roller 121 that is pushed into the main body casing together with the paper feed cassette 100 eventually comes into contact with the peripheral surface of the feeding roller 35 fixed in the main body casing. When the paper feed cassette 100 is further pushed into the main body casing, the separation roller 121 is pushed back to the feed roller 35. By this pushing back force, the swing holder 123 starts to revolve from the upper cover 126 side to the base cover 124 side around the swing shaft portion 123a against the biasing force of the coil spring 125. As a result, the separation roller 121 gradually revolves from the feeding roller 35 side toward the separation roller 121 side around the swing shaft portion 123a, and the contact portion of both rollers is also separated from the feeding roller 35 side. It gradually moves toward the roller 121 side. When the paper feed cassette 100 is pushed to the proper mounting position, the separation roller 121 is completely separated from the back surface of the upper cover 126.

  When a stiff sheet such as thick paper is used as the recording sheet S, the recording sheet S sandwiched in the separation nip pushes the separation roller 121 back in the direction away from the feeding roller 35 by a restoring force due to the strength of the waist. There is a fear. Then, non-feeding of the recording sheet S due to this force occurs. Specifically, the swinging holder 123 biased toward the feeding roller 35 by the coil spring 125 (see FIG. 8) is separated from the feeding roller 35 around the swinging shaft portion 123a by the above-described force. Revolving in the direction, the separation roller 121 is largely separated from the feeding roller 35. As a result, the conveying force due to the surface movement of the feeding roller 35 is not transmitted to the recording sheet S, and the recording sheet S is not fed. Hereinafter, this non-feed is referred to as “non-feed by pushing back”.

  FIG. 11 is a longitudinal sectional view showing the feeding roller 35 and the separation roller unit 120. Around the opening (126a) in the upper cover 126 of the separation roller unit 120, two convex portions 126b and 126c arranged in the roller axial direction are provided. In the figure, the alternate long and short dash line with the symbol Ln is an extension line of the separation nip. Moreover, the dashed-dotted line to which the code | symbol Ls was attached | subjected is an extension line of the surface of the convex part 126b or the convex part 126c. The convex portion 126b is separated in the main body casing while being arranged at a position closer to one end side along the rotation axis direction than one end surface in the rotation axis direction (right end surface in the drawing) of the cylindrical roller portion 121b of the separation roller 121. Projecting to the feeding roller 35 side from the nip. Further, the convex portion 126c is arranged at a position on the other end side along the rotation axis direction with respect to the other end surface in the rotation axis direction (left end surface in the figure) of the roller portion 121b, and is supplied from the separation nip in the main body casing. Projecting to the feed roller 35 side.

  As shown in FIG. 12, when the stiff recording sheet S is sandwiched between the separation nips, the portion of the recording sheet S in the roller axial direction that is in contact with the first contact portion 126b and the second contact. A region between the portion in contact with the portion 126c is slightly bent. Specifically, it bends toward the separation nip located on the separation roller 121 side with respect to the surface of the contact portion. Since the recording sheet S shown in the figure is a stiff sheet, if the sheet is bent in such a manner, the recording sheet S tries to eliminate the bending by the restoring force, and therefore the recording sheet S moves away from the feeding roller 35 with respect to the separation roller 121. No more power will be applied. As a result, it is possible to avoid the occurrence of “non-feed by pushing back” due to the stiff recording sheet S applying the aforementioned force to the separation roller 121 at the separation nip.

  In FIG. 11, the peripheral surface of the separation roller 121 protrudes to the outside through an opening provided in the upper cover 126, and slightly protrudes toward the feeding roller 35 from the surface of the upper cover 126 (hereinafter, protruding). The peripheral surface area is called the protruding peripheral surface). If the stiff recording sheet S conveyed toward the separation nip hits the protruding peripheral surface of the separation roller 121 on the near side of the separation nip, there is a risk of the following. That is, the swinging holder 123 revolves in the direction away from the feeding roller 35 with the swinging shaft portion 123a as the center, whereby the separation roller 121 is greatly separated from the feeding roller 35 and the recording sheet S is not fed. There is a risk of causing. Hereinafter, this non-feed is referred to as “non-feed due to the end”. In particular, in the configuration in which the driving force of the motor is not transmitted to the separation roller 121 as in this printer, even if the recording sheet S hits the protruding peripheral surface of the separation roller 121 and stops the driven rotation of the roller, the separation roller 121 Reverse drive is not applied. For this reason, since it is not possible to apply a force to push back the recording sheet S that hits the protruding peripheral surface of the separation roller 121 toward the cassette, “non-feed due to abutment” is likely to occur.

  Therefore, in this printer, the guide unit plate 127 is fixed to the upper cover 126 as shown in FIG. The guide unit plate 127 includes a separation nip guide portion 127a and two deflection imparting portions 127b. The separation nip guide portion 127a is disposed in front of the roller portion 121b of the separation roller 121 and contacts the recording sheet S before entering the separation nip. Then, the recording sheet S is guided toward the separation nip while preventing the recording sheet S before entering the separation nip from abutting against the peripheral surface of the separation roller 121. By preventing the recording sheet S from abutting against the protruding peripheral surface of the separation roller, it is possible to avoid the occurrence of “non-feed due to abutment” of the recording sheet S. In addition, the role of the two bending | flexion provision parts 127b in the guide unit board 127 is mentioned later.

Next, a characteristic configuration of the printer according to the embodiment will be described.
As already described, in a pickupless type image forming apparatus such as this printer, when a recording sheet S having a low stiffness is used, a sheet corrugation as shown in FIG. This makes it easier to crease the sheet.

  Therefore, in this printer, as shown in FIG. 10, the two deflection imparting portions 127 b are provided on the guide unit plate 127. The bending imparting portion 127b contacts the recording sheet S immediately before entering the separation nip from below in the gravity direction. As a result, as shown in FIG. 13, the recording sheet S having a low waist is bent to cause wrinkles along the conveying direction (arrow direction in the figure) on the recording sheet S. By forming this bend, in the recording sheet S, the occurrence of the bend in the direction orthogonal to the bend (FIG. 31) is inhibited. Thereby, generation | occurrence | production of the crease | fold of the recording sheet S can be suppressed.

  In FIG. 10, the separation nip guide portion 127 a is formed by bending a part of a sheet metal constituting the main body of the guide unit plate 127. Further, the base portions of the two deflection imparting portions 127b are also formed by bending a part of the sheet metal constituting the main body of the guide unit plate 127. However, in the bending imparting member 127b, the tip portion that contacts the back surface of the recording sheet S is not formed by bending the sheet metal of the main body, and is formed separately from the sheet metal.

  In the model under development, the present inventors used an entire region from the base to the tip formed by bending a sheet metal, unlike the illustrated bending imparting portion 127b. In addition, in the model under development, it was easy to cause “non-feed due to slip” in addition to “non-feed due to push-back” and “non-feed due to end of contact” as described above. This “non-feed due to slip” occurs as follows. That is, the bending applying unit strongly presses the recording sheet S toward the feeding roller, thereby applying a large conveyance resistance to the recording sheet S and causing the recording sheet S to slip on the surface of the feeding roller. This slip makes it impossible to feed the recording sheet S in the transport direction, and causes “non-feed due to slip”.

  Therefore, in this printer, as shown in FIG. 14, the tip end portion 127d that contacts the recording sheet is formed of a material different from that of the main body portion 127c made of sheet metal, in the entire region of the deflection imparting portion 127b. . Specifically, a resin sheet that is a flexible member is used as the material. This resin sheet can be freely bent by applying a certain amount of force. However, when the recording sheet S is thin, such as thin paper, when the recording sheet S contacts the recording sheet S, the strength of the waist of the recording sheet S exceeds the waist strength of the recording sheet S. Therefore, maintain a straight posture without bending. As a result, the recording sheet S having a low waist is bent as shown in FIG. On the other hand, when a stiff sheet such as cardboard is used as the recording sheet S, as shown in FIG. 15, the recording sheet S itself is directed toward the downstream side in the sheet conveying direction in accordance with the contact with the recording sheet S. Flexible. By bending in this way, the force of pressing the recording sheet in the separation nip toward the feeding roller 35 is reduced to reduce the conveyance resistance, so that the slippage of the recording sheet S on the surface of the feeding roller 35 is stiff. Reduce the occurrence of As a result, the occurrence of “non-feed due to slip” of the stiff recording sheet S can be suppressed.

  FIG. 16 is an enlarged configuration diagram illustrating the separation nip and the surrounding configuration in an enlarged manner. In the figure, arrows indicate the conveyance path of the recording sheet S from the bottom plate pad 102 of the movable bottom plate 101 to the separation nip. Since the recording sheet (not shown) has a small sheet-like thickness, the recording sheet moves substantially in the position of the arrow and enters the separation nip. In the bending imparting portion 127b of the guide unit plate 127, the main body portion 127c made of sheet metal exists on the lower side (the separation roller 121 side) than the conveyance path indicated by the arrow, so that the recording sheet S is placed on the main body portion 127c. It is rare to touch. On the other hand, it can be seen that the front end portion 127a made of a resin sheet protrudes greatly upward in the gravitational direction from the conveyance path (projects greatly toward the feeding roller 35). As described above, the leading end portion 127d protrudes greatly upward in the gravitational direction from the conveyance path indicated by the arrow, so that the recording sheet S can be reliably brought into contact with the recording sheet S to bend. On the other hand, the main body 127c made of metal is positioned below the conveyance path in the direction of gravity, thereby preventing the recording sheet S from being pushed toward the feeding roller 121 by the main body 127c having high rigidity. be able to. In addition, the bending | flexion provision part 127b shown by the figure is located in the front side in a figure rather than the roller part of the feed roller 35 or the roller part of the separation roller 121 in the roller axial direction. For this reason, in the roller axis direction, the recording sheet is lifted above the conveyance path by the deflection imparting section 127b at the position of the deflection imparting section 127b, but the recording sheet moves at the position of the conveyance path at the separation nip position.

  FIG. 17 is an exploded perspective view showing the bending imparting portion 127b in the guide unit plate 127. FIG. The bending imparting portion 127b is formed by a sheet metal that is a main body forming member that forms the main body portion 127c and a resin sheet that is a front end portion forming member that forms the front end portion 127d. By using a resin sheet or the like that is different from the sheet metal of the main body portion 127c as the material of the distal end portion 127d, desired flexibility can be easily exerted on the distal end portion 127d as designed.

As shown in FIG. 18, the sheet metal for forming the main body portion 127 c of the deflection imparting portion 127 b and the resin sheet for forming the tip end portion 127 d are respectively a rising portion α, a refracting portion β, and A tip extending portion γ is provided. The rising portion α is a portion that rises upward from below in the direction of gravity. In addition, the refracting portion β is a portion that is refracted from the sheet feeding cassette side toward the separation nip side in the sheet conveyance direction at the position of the upper end of the rising portion α. Further, the leading end extending portion γ is a portion extending from the refracting portion β toward the leading end side in contact with the recording sheet S.

FIG. 19 is a side view showing the guide unit plate 127. In the figure, the direction from the left side to the right side in the drawing is the sheet conveying direction. A region on the right side of the drawing with respect to the guide unit plate 127 is a region on the separation roller side with the guide unit plate 127 as a boundary in the sheet conveyance direction. The area on the left side of the drawing with respect to the guide unit plate 127 is an area on the sheet feeding cassette side with the guide unit plate 127 as a boundary in the sheet conveying direction. On the surface on the separation nip side of the rising portion α of the sheet metal as the main body forming member, the surface on the sheet feeding cassette side at the rising portion α of the resin sheet as the tip portion forming member is fixed by a double-sided tape 127e. Further, the surface on the separation roller side at the rising portion α of the resin sheet is fixed to an upper cover (126 in FIG. 8) of the separation roller unit by a double-sided tape 127f. By fixing them, the tip end portion (127d) made of a resin sheet of the deflection applying portion (127b) is firmly fixed to the main body portion (127c) made of sheet metal.

However, the leading end extension γ of the resin sheet is not fixed to a sheet metal or other member. The front end extending portion γ of the resin sheet is cantilevered by the refracting portion β of the resin sheet in a state of being positioned below the front end extending portion γ of the sheet metal in the direction of gravity. As a result, the distal end extending portion γ of the resin sheet functioning as the distal end portion 127d of the deflection applying portion 127b can freely swing (bend) around the refracting portion β of the resin sheet. And compared with the case where the front-end | tip extension part (gamma) of a resin sheet is affixed on the lower surface of the front-end | tip extension part (gamma) of a sheet metal, the front-end | tip part 127d can be favorably bent. Further, when the front end extension γ of the resin sheet is attached to the lower surface of the front end extension γ of the sheet metal, the front end extension γ and the rising portion α of the resin sheet with the refracting part β of the resin sheet as a boundary However, in this case, the working efficiency is remarkably deteriorated. By making the resin sheet affixed at one place of the rising portion α, it is possible to avoid deterioration in work efficiency.

  In FIG. 18, the distal end extending portion γ of the resin sheet forming the distal end portion 127 c of the deflection imparting portion (127 b in FIG. 17) is chamfered in a curved shape. By this chamfering, it is possible to prevent the recording sheet S from being damaged by rubbing the corner of the leading end portion 127c against the recording sheet S. In addition, the edge extending portion γ of the sheet metal forming the main body portion (127c in FIG. 17) of the bending imparting portion is also chamfered in a curved shape. As a result, even when the recording sheet S, which is stiff, bends the leading end 127c and comes into contact with the main body, the recording sheet S is not rubbed at the corners of the main body. Therefore, it is possible to prevent the recording sheet S from being damaged by rubbing the stiff recording sheet S with the corners of the main body made of sheet metal. In particular, when jamming the recording sheet S having a strong waist, even when the operator pulls the recording sheet S having a strong waist and removes the recording sheet S from the apparatus, the recording sheet S may be rubbed against the main body made of sheet metal. Since the corners of the sheet metal are not applied, the occurrence of scratches can be avoided.

  As shown in FIG. 13, in this printer, the guide unit plate 127 contacts different portions in a direction (hereinafter referred to as a conveyance orthogonal direction) orthogonal to the sheet conveyance direction (arrow direction in the figure) of the recording sheet S. The two bending | flexion provision parts 127b to perform are provided. Accordingly, by generating two wrinkles arranged in the conveyance orthogonal direction with respect to the recording sheet S, the undulation of the recording sheet S is inhibited with a stronger force. Therefore, the occurrence of folds in the recording sheet S can be suppressed more reliably.

  By the way, if the wrinkles generated on the recording sheet S due to the bending applied by the bending applying unit 127b enter the separation nip, the recording sheet S may be folded. The bend imparting portion 127b provided in order to avoid the occurrence of the fold may cause the crease to be promoted instead of being promoted. Therefore, this printer employs the following configuration. That is, in FIG. 10, only the cylindrical roller portion of the separation roller 121 is drawn. One of the two deflection imparting portions 127b is provided at a position shifted to one end side (right side in the drawing) in the rotation axis direction (arrow B direction) from the roller portion of the separation roller 121. The other side is provided at a position shifted from the roller portion of the separation roller 121 to the other end side (left side in the drawing) in the rotation axis direction. By arranging the two deflection imparting portions 127b in this manner, the two wrinkles generated on the sheet by the deflection imparting portion 127b in FIG. 13 are both positioned outside the separation nip in the rotation axis direction. Thereby, the generation | occurrence | production of the crease | fold by making the wrinkles generated on the sheet | seat by the bending | flexion provision part 127b approach a separation nip can be avoided.

  As shown in FIG. 16, in the guide unit plate 127, the extending direction of the guide portion, which is the distal end portion of the separation nip guide portion 127a, and the extending direction of the distal end portion 127d of the deflection applying portion 127b are different from each other. Thus, by making the extending directions different from each other, the following two functions can be satisfactorily exerted on the guide unit plate 127, respectively. That is, it has a function of guiding the recording sheet S to the separation nip with respect to the separation nip guide member 127a, and a function of generating a sheet wrinkle for preventing the sheet waviness on the recording sheet S by the deflection applying portion 127b. In this printer, the extending direction of the guide portion, which is the distal end portion of the separation nip guide portion 127a, is laid down closer to the horizontal direction than the extending direction of the distal end portion 127d of the deflection imparting portion 127b, so that these two functions can be achieved. Each of them is made independent and performs well.

  Up to this point, three non-feeds that may occur in the printer have been described: “non-feed due to pushing back”, “non-feed due to abutment”, and “non-feed due to slip”. May also occur. “Non-feed due to sheet curl”. As shown in FIG. 20, this “non-feeding by sheet curl” is such that both ends of the sheet feeding cassette in the direction perpendicular to the conveyance direction (the arrow direction in the figure) are perpendicular to the center part. It is generated by curling so as to protrude upward. As shown in FIG. 21, the curled recording sheet S is brought into contact with the paper feed roller unit case 39 with both ends projecting upward immediately after being sent out from the paper feed cassette 100. It becomes difficult to move toward the separation nip. This causes “non-feed due to sheet curl”.

  Therefore, in this printer, as shown in FIG. 22, the curl correction body 104 is provided on the movable bottom plate 101 of the paper feed cassette 100. The curl corrector 104 is disposed so as to protrude above the sheet placement surface of the movable bottom plate 101 and is orthogonal to the sheet feeding direction (arrow direction in the figure) of the recording sheet S in the sheet feeding cassette 100. It contacts the central part (hereinafter referred to as the delivery orthogonal direction). By this contact, the curl of the recording sheet S is corrected by pushing the central portion in the orthogonal direction of the recording sheet S upward.

  When the curl correcting body 104 is not provided, as shown in FIG. 23, both ends of the leading end of the recording sheet S in the sheet feeding cassette 100 in the feeding orthogonal direction protrude above the sheet placement surface. ing. Then, the protruding portion hits the feeding roller unit case. On the other hand, when the curl correction body 104 is provided as in the present printer, as shown in FIG. 24, the leading end of the recording sheet S accommodated in the paper feed cassette 100 is in the direction orthogonal to the delivery. The entire area is in close contact with the sheet placement surface. By being sent out from the paper feed cassette 100 in this state, it is possible to enter the separation roller without hitting the feed roller unit case.

  As shown in FIG. 25, the curl correction body 104 is configured to be detachable from the movable bottom plate 101. In addition, as shown in FIG. 26, while being engaged with the movable bottom plate 101, it is slid along the sheet feeding direction (in the direction of arrow A in the figure) or the opposite direction while being held by the movable bottom plate 101. ing. In addition, as shown in FIG. 27, there are three engaging portions that engage with the movable bottom plate 101: a first engaging portion 104a, a second engaging portion 104b, and a third engaging portion 104c. Yes. The first engaging portion 104a is engaged with the movable bottom plate 101 so as to minimize the amount of protrusion from the sheet placement surface in the curl correction body 104 in a state of being engaged with the movable bottom plate 101 among the three engaging portions. To match. The second engagement portion 104b is movable so that the amount of protrusion from the sheet placement surface of the curl correction body 104 in a state of being engaged with the movable bottom plate 101 among the three engagement portions is the second smallest. It engages with the bottom plate 101. In addition, the third engagement portion 104c has a movable bottom plate 101 that maximizes the amount of protrusion from the sheet placement surface of the curl correction body 104 that is engaged with the movable bottom plate 101 among the three engagement portions. Is engaged.

  The degree to which the curl correction body 104 corrects the posture of the recording sheet S varies depending on the position of the curl correction body 104 in the sheet feeding direction on the movable bottom plate 101 and the amount of protrusion of the curl correction body 104 from the sheet placement surface. . Then, as shown in FIG. 24, the recording sheet S can be obtained by bringing the entire region in the feeding orthogonal direction of the leading end portion of the recording sheet S accommodated in the sheet feeding cassette 100 into close contact with the sheet placement surface. It is possible to avoid hitting the feed roller unit case. That is, it is possible to avoid the occurrence of “non-feed due to contact”. However, in order to correct the posture of the recording sheet S to the posture shown in FIG. 24, it is necessary to set the position and the protruding amount to values according to the waist strength of the recording sheet S. Therefore, the curl correction body 104 is slidably engaged with the movable bottom plate 101 as shown in FIG. 26, and a plurality of engaging portions are provided in the curl correction body 104 as shown in FIG. is there. Thereby, the position and the protrusion amount can be finely adjusted to values corresponding to the waist strength of the recording sheet S, and the occurrence of “non-feed due to abutment” can be reliably avoided.

  FIG. 28 is a perspective view showing a modified example of the curl correction body 104 together with the movable bottom plate 101 and the like. As shown in the figure, a rotatable roller 104d may be provided on the curl correction body 104 and pressed against the recording sheet S from below in the direction of gravity. When the lowest-order recording sheet S is sent out from the sheet feeding cassette, the roller 104d is driven to rotate following the movement of the recording sheet S, thereby avoiding the friction between the curl correction body 104 and the recording sheet S. As a result, it is possible to avoid an increase in sheet conveyance resistance and damage due to rubbing.

  FIG. 34 is a perspective view showing a main part of the feeding roller 35. The feeding roller 35 includes a resin hub 35a, an elastic layer 35e, and a metal rotating shaft member (not shown). The hub 35a includes an inner ring 35b, an outer ring 35c containing the inner ring 35b, and six ribs 35d extending radially from the outer peripheral surface of the inner ring 35b and connected to the inner periphery of the outer ring 35c. The elastic layer 35e is made of an elastic material such as rubber and is covered on the outer peripheral surface of the outer ring 35c of the hub 35a. The rotary shaft member (not shown) is rotatably received by bearings (not shown) at both ends in the longitudinal direction in a state where the rotary shaft member is inserted into the inner space of the inner ring 35b of the hub 35a.

  Since the hollow hub structure as shown in the figure and the resin-made hub 35a are easy to mold, it can be manufactured at low cost. However, because of its light weight, there is a problem that it generates noise by vibrating at a high frequency as it rotates. The present inventors made a prototype of a roller 935 shown in FIG. The hub 935a of the roller 935 includes an inner ring 350b and an outer ring 350c, as well as an intermediate ring 350f disposed therebetween. The rib 350d extends from the outer peripheral surface of the inner ring 350b and is connected to the inner peripheral surface of the middle ring 350f. Between the middle ring 350f and the outer ring 350c is a ring-shaped space that does not include the rib 350d, and a metal weight 350g is press-fitted into the space. By increasing the load of the roller 935 by the weight 350g, the vibration of the feeding roller 935 can be suppressed and the generation of noise can be reduced. FIG. 35 is a side view showing the roller 935 from one end side in the rotational axis direction, and does not show a cross section of the roller 935, but the weight 350g is hatched for easy viewing. The same applies to FIG. 36 described later.

  However, in such a configuration, the following new problem has occurred. In other words, the roller 935 is used with a weight of 350 g fitted in a model with an emphasis on noise reduction, while the roller 935 is used without being fitted with a weight 350 g in a model with an emphasis on weight reduction. It is desirable to be excellent. However, it has been found that when the weight 350 g is not fitted, the weight is easily deformed. Specifically, when the weight 350g is not fitted, the space between the middle ring 935f and the outer ring 935c is hollow. Since it is assumed that 350 g of weight is put in the hollow, no rib can be provided between the middle ring 935 f and the outer ring 935 c. For this reason, compared with the case where a rib is provided, the outer ring 935c is easily deformed in the radial direction. In particular, when another roller is pressed to form a nip, the outer ring 935c may be deformed so as to gradually fall toward the center of rotation due to the nip pressure. Further, when the weight 350g is fitted, the outer ring 935c may bulge outward due to the press-fitting of the weight 350g, and the outer diameter of the roller 935 may be increased.

  Therefore, the feeding roller 35 of the printer according to the embodiment does not employ the configuration in which the middle wheel 935f such as the roller 935 is provided, but adopts the following configuration. FIG. 36 is a side view showing the main part of the feeding roller 35 of the printer from one end side in the rotation axis direction. In the feeding roller 35, a weight 35g is fitted between two adjacent ribs 35d. There are a total of six spaces partitioned by the ribs 35d (hereinafter referred to as rib partition spaces), and 35 g of weights are placed in each of the three rib partition spaces. In order to prevent an extreme deviation in weight, the rib partition space with the weight 35 g and the rib partition space without the weight are alternately arranged in the rotation direction. In such a configuration, since the outer ring 35c is firmly reinforced by the ribs 35d, the outer ring 35c is not deformed even when the weight 35g is not fitted. Therefore, the versatility of the feeding roller 35 can be improved. Further, even when the weight 35g is fitted, the outer ring 35c reinforced by the rib 35d does not bulge outward, so that an increase in the outer diameter of the feeding roller 35 can be avoided.

  FIG. 37 is an enlarged configuration diagram showing the weight 35g in an enlarged manner. An arrow A direction in the drawing indicates a rotation direction of a feeding roller (not shown). Further, the arrow B direction in the figure indicates the rotation axis direction. The weights 35g have protrusions z at both ends in the rotational direction. The protrusion z extends over the entire area of the weight 35g in the rotation axis direction.

  FIG. 38 is a partial side view showing the rib partition space of the feeding roller 35 partially enlarged. It is desirable that the weight 35g is firmly fixed so as not to rattle in the rib partition space. Since a force in the centrifugal direction is applied to the weight 35g in the rib partition space by centrifugal force, if the weight 35g is fixed at a position separated from the inner peripheral surface of the outer ring 35c, the weight 35g is increased by the large centrifugal force. There is a risk of unlocking. For this reason, the weight 35g is fixed in a state of being in close contact with the inner peripheral surface of the outer ring 35c. Specifically, in the figure, Lb indicates the distance between the protrusion position ribs. This is because a position where one of the two projections (z) of the weight 35g placed in the rib partitioning space contacts one of the two ribs 35d forming the rib partitioning space, and the other projection is the other rib It is a distance from the position which contacts 35d. Moreover, in the same figure, La has shown the distance between protrusions as the distance of the front-end | tip of one protrusion, and the front-end | tip of the other protrusion. As illustrated, the inter-projection distance La is greater than the inter-projection position rib distance Lb. In the drawing, for the sake of convenience, the state in which the protrusion is biting into the rib 35d is depicted, but actually, the protrusion position rib distance Lb is caused by the bending of the rib 35d rather than such biting. A larger weight 35g between the protrusions La can be accommodated in the rib partition space. As a result, the weight 35g is firmly fitted in the rib space without rattling. In addition, even if the number of protrusions is only one, the weight 35g can be firmly fitted in the partition space by forming the weight 35g in a shape that can reliably abut the protrusion on the rib 35d. is there.

  About protrusion, it is desirable to provide in the position which contacts the center part of the roller radial direction in rib 35d. By doing so, the rib 35d can be easily bent by the abutment of the protrusion, and the fixing operability of the weight 35g can be improved. In addition, by bending the rib 35d relatively large by the protrusions, the weight 35g can be fixed in the rib partition space without rattling, regardless of the expansion and contraction of the weight 35g due to temperature change.

  In order to bend the rib 35d by the abutment of the weight 35g, it is desirable that the rib partition space disposed adjacent to the rib partition space into which the weight 35g is placed be an empty space into which the weight 35g is not placed. In addition, it is desirable to alternately arrange the rib partition spaces into which the weights 35 g are placed and the partition spaces into which the weights 35 g are not put in order to make the weight balance in the circular direction as uniform as possible. And in order to implement | achieve them simultaneously, about the number of rib partition spaces, it is desirable to make it even.

  In FIG. 38, the resin hub includes a gate circle portion 35h generated during molding. Even if such a gate circle portion 35h is generated, the weight 35g is formed in a shape that avoids it as shown in the figure, so that the gate circle portion 35h is not removed by cutting or the like. Can be set in the rib partition space. In addition, the sub rib which bridge | crosslinks between the mutually adjacent ribs 35d may be provided, and a rib partition space may be partitioned into the space inside on the radial direction, and the space outside. In this case, it is desirable to put the weight 35g in the outer space in order to obtain a relatively large noise reduction effect with the relatively small weight 35g.

  As shown in FIG. 37, the protrusion of the weight 35g is desirably extended over the entire area in the rotation axis direction of the weight 35g. In this way, when the weight 35g is inserted into the rib partition space, the protrusion is not caught on the rib 35d during the insertion, and therefore the insertion property of the weight 35g can be improved.

  FIG. 39 is a side view showing the main part of the feeding roller 35 of the printer according to the modification from one end side in the rotation axis direction. In the feeding roller 35, no projection is provided on the weight 35g, and a gap is formed between the weight 35g in close contact with the outer ring 35c and the two ribs 35d. By filling the gap with the adhesive 35i, the weight 35g is fixed to the rib 35d. As the adhesive 35i, an adhesive having a property of preventing elasticity due to a difference in shrinkage between the metal body and the hub of the resin material due to environmental change by having elasticity after curing is used.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
[Aspect A]
In the aspect A, a sheet storage unit (for example, a paper feed cassette 100) that stores a recording sheet (for example, the recording sheet S) therein, and a feeding body on which the recording sheet stored in the sheet storage unit is pressed ( For example, the recording sheet fed out from the sheet storing means by the surface movement of the feeding roller 35) is sandwiched in the separation nip due to the contact between the feeding body and the separating body (for example, the separation roller 121), and the recording sheet is moved in the separation nip. Separation feeding means (for example, a combination of the feeding roller 35 and the separation roller unit 120) that separates only the recording sheets that are in direct contact with the feeding body among the recording sheets that overlap each other, and the separation feeding And an image forming unit that forms an image on a recording sheet separated into one sheet by a feeding unit. A deflection imparting body (e.g., a flexure imparting portion 127b) is provided that deflects the recording sheet before the recording sheet by its own contact and generates wrinkles extending in the transport direction on the recording sheet, and recording in the deflection imparting body A tip portion (for example, 127d) that contacts the sheet is formed of a flexible member (for example, a resin sheet).

  In such a configuration, in the pickup-less type image forming apparatus, a wrinkle extending along the conveyance direction is generated on the recording sheet before the deflection imparting body enters the separation nip, so that it is orthogonal to the conveyance direction of the recording sheet. This prevents the occurrence of bending in the direction of The undulation of the recording sheet as shown in FIG. 31 is generated by causing the recording sheet to bend in a direction orthogonal to the conveyance direction at a plurality of locations. Development is inhibited. In this way, by inhibiting the occurrence of undulation of the recording sheet in the vicinity of the separation nip, it is possible to suppress the occurrence of a fold of the recording sheet that is weak.

  Further, in the aspect A, when the distal end portion made of the flexible member of the deflection imparting body comes into contact with a recording sheet having a low waist before the separation nip, the deflection imparting body flexes flexibly before the separation nip. Reduce the lift of the recording sheet. This reduces the area where the recording sheet is pressed against the surface of the feeder on the near side of the separation nip and suppresses the occurrence of slip on the surface of the feeder of the recording sheet having a strong stiffness. The occurrence of non-feeding of the recording sheet can be suppressed.

[Aspect B]
In the aspect B, in the aspect A, the deflection imparting body is disposed so as to bring the leading end portion into contact with the recording sheet before entering the separation nip from below in the gravity direction, and the entire area of the deflection imparting body Of these, only the leading end portion protrudes upward in the gravitational direction from the recording sheet conveyance path toward the separation nip from the inside of the sheet storage means. In such a configuration, as described in the embodiment, the leading edge of the deflection imparting body reliably generates the wrinkles extending in the transport direction on the recording sheet, and reliably suppress the occurrence of “non-feed due to slip”. Can do.

[Aspect C]
Aspect C is the aspect B, wherein at least the main body forming member (for example, a sheet metal) that forms the main body and the front end portion forming member (for example, a resin sheet) that forms the front end portion while being fixed to the main body. It is characterized in that an imparting body is formed. In such a configuration, as described in the embodiment, desired flexibility can be easily exhibited as designed with respect to the distal end portion of the deflection imparting body.

[Aspect D]
Aspect D is the aspect C according to aspect C, wherein a rising portion (for example, a rising portion α) that rises upward from below in the direction of gravity and a position of the separation nip from the side of the sheet storage unit in the sheet conveyance direction at the upper end position of the rising portion. A combination of a refracting part (for example, a refracting part β) that refracts toward the side and a tip extending part (for example, a tip extending part γ) that extends from the refracting part toward the tip side, The sheet is provided in each of the main body forming member and the leading end forming member, and the sheet is accommodated in the sheet conveying direction of the rising portion of the leading end forming member on the surface on the separation nip side in the sheet conveying direction of the rising portion of the main body forming member. The surface on the means side is fixed, and the tip extension portion of the tip portion forming member is below the tip extension portion of the main body forming member in the gravitational direction. Is characterized in that in a state of being positioned was cantilevered on the bent portion of the tip forming member without fixing to the distal end extension of said body forming portion. In such a configuration, as described in the embodiment, the distal end portion of the deflection imparting body is flexed better than when the distal end extending portion of the distal end forming member is attached to the lower surface of the distal end extending portion of the main body forming portion. I can do it. Thereby, the occurrence of “non-feed due to slip” can be suppressed satisfactorily.

[Aspect E]
Aspect E is characterized in that, in any one of Aspects A to D, a plurality of the deflection imparting bodies that come into contact with different locations in the direction orthogonal to the recording sheet conveyance direction are provided as the deflection imparting bodies. It is. In such a configuration, a plurality of creases that are arranged in the conveyance orthogonal direction with respect to the recording sheet are generated by the plurality of deflection imparting bodies, thereby inhibiting the undulation of the recording sheet with a stronger force. Can be suppressed more reliably.

[Aspect F]
Aspect F uses a rotatable separation roller as the separation body in aspect E, and at least one deflection imparting body is shifted to one end side in the rotational axis direction from the columnar roller portion of the separation roller. And at least one other deflection imparting body is provided at a position shifted to the other end side in the rotational axis direction from the roller portion. In this configuration, as described in the embodiment, it is possible to suppress the occurrence of a fold in the recording sheet due to the sheet wrinkles generated by the deflecting applicator.

[Aspect G]
Aspect G is any one of the aspects A to F, wherein the recording sheet before entering the separation nip is brought into contact with the recording body before contacting the separation body by contacting the recording sheet before entering the separation nip. In addition, a separation nip guide body (for example, a separation nip guide portion 127a) for guiding the recording sheet toward the separation nip is provided. In such a configuration, as described in the embodiment, it is possible to avoid the occurrence of “non-feed due to abutment” by preventing the abutment of the recording sheet against the separation body by the separation nip guide body.

[Aspect H]
Aspect H is characterized in that, in aspect G, the extending direction of the guide portion of the separation nip guide body and the extending direction of the tip end portion of the deflection imparting body are different from each other. In such a configuration, as described in the embodiment, the following two functions can be made independent and can be performed well. That is, a function of guiding the recording sheet to the separation nip with respect to the separation nip guide body, and a function of generating a sheet wrinkle for preventing the sheet waviness on the recording sheet by the deflection imparting body.

[Aspect I]
Aspect I is any one of Aspects A to H, and is disposed so as to protrude from the sheet placement surface of the sheet storage unit, and is centered in a direction perpendicular to the sheet feeding direction of the recording sheet in the sheet storage unit. A curl correction body (for example, a curl correction body 104) that corrects the curling of the recording sheet by contacting the recording section is provided so as to be detachable from the sheet storage means. In such a configuration, as described in the embodiment, occurrence of “non-feed due to sheet curl” can be suppressed.

[Aspect J]
Aspect J is the aspect I according to aspect I, wherein a plurality of engaging portions (for example, first engaging portions 104a) respectively engaged with the sheet storing means so that the amount of protrusion of the curl correction body from the sheet placement surface is different from each other. The second engaging portion 104b and the third engaging portion 104c) are provided on the curl correction body. In such a configuration, as described in the embodiment, the amount of protrusion from the sheet placement surface of the curl correction body is finely adjusted to a value corresponding to the waist strength of the recording sheet, and the occurrence of “non-feed due to contact” occurs. Can be reliably avoided.

[Aspect K]
Aspect K is any one of the aspects A to J. As the feeder, an inner ring (for example, inner ring 35b), an outer ring (for example, outer ring 35c) containing the inner ring, and a radially extending outer periphery of the inner ring A rotatable feeding rotating body (for example, a feeding roller) provided with a plurality of ribs (for example, rib 35d) connected to the inner circumference and an elastic layer (for example, elastic layer 35e) made of an elastic body coated on the outer circumference of the outer ring. 35), and a weight (for example, 35 g) is fixed in a space between the plurality of ribs arranged inside the outer ring. In such a configuration, as described in the embodiment, the versatility of the feeding rotator can be enhanced, and an increase in the outer diameter of the feeding rotator due to the insertion of a weight can be avoided.

[Aspect L]
The aspect L is the aspect K, in which the weight has protrusions on one end surface and the other end surface in the rotation direction of the feeding rotating body, and the two ribs located at the positions sandwiching the space One of the two protrusions is brought into contact, the other rib is brought into contact with the other protrusion, and a portion different from the two protrusions of the weight is brought into contact with the inner peripheral surface of the outer ring. It is characterized by being. With this configuration, it is possible to avoid rattling of the weight in the space.

[Aspect M]
In the aspect M, the distance between the protrusion position ribs connecting the contact position of the two ribs with the protrusion and the contact position of the other rib with the protrusion in a straight line is the difference between the two ribs. It is characterized by being smaller than the distance between the tips. In such a configuration, the weight can be pressed into the space and fixed firmly.

[Aspect N]
Aspect N is characterized in that, in aspect M, the protrusion is extended over the entire area of the weight in the direction of the rotation axis of the feeder. In such a configuration, when the weight is inserted into the space between the ribs, the protrusion is not caught on the rib in the middle of the insertion, so that the insertion property of the weight can be improved.

[Aspect O]
Aspect O is characterized in that, in aspect K, the weight is fixed to the rib with an adhesive. In such a configuration, the weight can be fixed to the rib without deforming the rib by press-fitting the weight.

[Aspect P]
Aspect P is characterized in that in any one of the aspects K to O, the weight is shaped so as to avoid a gate portion formed at the time of forming the hub having the inner ring, the outer ring, and the rib. is there. In such a configuration, the manufacturing cost can be reduced by placing the weight in the space of the feed rotating body without removing the gate portion by cutting or the like.

1: Photoconductor (part of image forming means)
2: Cleaning blade (part of image forming means)
3: Collection screw (part of image forming means)
4: Charging roller (part of image forming means)
7: Latent image writing device (part of image forming means)
8: Developing device (part of image forming means)
9: Toner cartridge (part of image forming means)
10: Transfer roller (part of image forming means)
35: Feeding roller (feeding member, part of separating feeding means)
100: Paper feed cassette (sheet storage means)
104: Curled correction body 104a: 1st engagement part 104b: 2nd engagement part 104c: 3rd engagement part 120: Separation roller unit (a part of separation feeding means)
127: Guide unit plate 127a: Separation nip guide (separation nip guide)
127b: Deflection imparting part (deflection imparting body)
127c: body portion 127d: leading end portion α: rising portion β: refraction portion γ: leading end extending portion S: recording sheet

JP-A-6-255810

Claims (10)

An image including separation feeding means for separating and feeding a sheet that is in direct contact with the feeding body at a separation nip where the feeding body and the separation body abut from a sheet other than the sheet that is in direct contact with the feeding body. In the forming device,
The tip from below the sheet in the sheet conveyance direction upstream side of the separation nip to form a tip portion of the flexure imparted portion contacts the tip of the flexible and a rising portion and a distal end extension facing from the lower side to the upper side The front end extension portion is not fixed to another member by fixing the forming member, and the front end extension portion is fixed by fixing each of the upstream side surface and the downstream side surface of the rising portion to the other member. To bend,
In the width direction orthogonal to the sheet conveying direction, the front end extending portion is located outside the end opposite to the separation nip and at the downstream side of the front end extending portion in the sheet conveying direction. An image forming apparatus comprising a convex portion with which the tip contacts. The image forming apparatus according to claim 1.
An image forming apparatus comprising: a plurality of the front end portion forming members that come into contact with different portions in a direction orthogonal to the sheet conveyance direction as the front end portion forming member. The image forming apparatus according to claim 2.
As the separator, a rotatable separation roller is used,
The at least one tip portion forming member is provided at a position shifted to one end side in the rotation axis direction from the cylindrical roller portion of the separation roller, and at least one other tip portion forming member is disposed at a position higher than the roller portion. An image forming apparatus provided at a position shifted to the other end side in the rotation axis direction. The image forming apparatus according to any one of claims 1 to 3,
A separation nip guide that guides the sheet toward the separation nip while preventing the sheet before entering the separation nip from hitting the separation body by contacting the sheet before entering the separation nip. An image forming apparatus comprising a body. The image forming apparatus according to claim 4.
An image forming apparatus, wherein an extending direction of the guide portion of the separation nip guide body and an extending direction of the tip end of the tip portion forming member are different from each other. The image forming apparatus according to claim 1,
Curl correction that corrects the curl of the sheet by being arranged so as to protrude from the sheet placement surface of the sheet storage means and contacting the center of the sheet in the sheet storage means in the direction orthogonal to the sheet feeding direction. An image forming apparatus, wherein a body is detachably attached to the sheet storage means. The image forming apparatus according to claim 6.
An image forming apparatus comprising: a plurality of engaging portions that respectively engage with the sheet storage unit so that the amount of protrusion of the curl correction body from the sheet placement surface is different from each other. . The image forming apparatus according to claim 1,
As the feeder, an inner ring, an outer ring including the inner ring, a plurality of ribs extending radially from the outer periphery of the inner ring and connected to the inner periphery of the outer ring, and an elastic body covered on the outer periphery of the outer ring An image forming apparatus characterized in that a rotatable feed rotating body having a layer is used and a weight is fixed in a space between the plurality of ribs arranged inside the outer ring. 9. The image forming apparatus according to claim 8, wherein
The weight has protrusions on one end surface and the other end surface in the rotation direction of the feeding rotating body, and contacts one of the two protrusions with one of the two ribs at a position sandwiching the space, An image forming apparatus characterized by having a size and a shape in which the other of the protrusions is brought into contact with the other of the ribs, and a portion different from the two protrusions of the weight is brought into contact with the inner peripheral surface of the outer ring. An image including separation feeding means for separating and feeding a sheet that is in direct contact with the feeding body at a separation nip where the feeding body and the separation body abut from a sheet other than the sheet that is in direct contact with the feeding body. In the forming device,
The tip from below the sheet in the sheet conveyance direction upstream side of the separation nip to form a tip portion of the flexure imparted portion contacts the tip of the flexible and a rising portion and a distal end extension facing from the lower side to the upper side The front end extension portion is not fixed to another member by fixing the forming member, and the front end extension portion is fixed by fixing each of the upstream side surface and the downstream side surface of the rising portion to the other member. To bend,
A separation nip guide that guides the sheet toward the separation nip while preventing the sheet before entering the separation nip from hitting the separation body by contacting the sheet before entering the separation nip. An image forming apparatus comprising a body.

Images