Sheet feeding device and image forming device provided with same

This sheet feeding device is provided with a fixed frame having a first feed roller, and a turning frame which, through rotation from a closed position to an open position, exposes a sheet feed path. The turning frame includes: a second feed roller with an integrally rotatable feed gear which forms a nip together with the first feed roller; a cleaning member configured to wipe the second feed roller; and a transmission gear. The fixed frame includes a fixed gear for engaging the transmission gear. The transmission gear, through turning of the turning frame to the open position, engages the feed gear, and rotates the second feed roller.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2013-135158, filed Jun. 27, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present disclosure relates to a sheet feeding device for feeding sheets, such as paper onto which images are to be printed; and to an image forming device provided with the same.

Sheet feeding devices for feeding paper (sheets) are incorporated into image forming devices that print images onto paper for output. In such an image forming device, feed rollers are situated along a paper feed path, and the paper is fed by rotating the feed rollers.

The feed rollers contact the paper to feed the paper through frictional force exerted against the paper. At this time, paper dust may be produced as the paper is abraded by the feed rollers, the paper dust becoming deposited on the feed roller. Moreover, due to abrasion of the paper feed path and the paper during paper feed, paper dust is produced at that time as well, and becomes deposited on the feed roller. According, various techniques for cleaning feed rollers have been proposed to date. For example, in the prior art, a cleaning member composed of a sponge was abutted against the feed roller. In so doing, paper dust deposited on the feed roller is scraped off by the cleaning member as the feed roller rotates during paper feed.

When the cleaning member is abutted against the feed roller, paper dust gradually accumulates in the abutting section of the feed roller and the cleaning member. As the paper dust accumulates, the paper dust becomes packed into a clump. Clumps of paper dust sometimes slip through the abutting section of the feed roller and the cleaning member and are transferred to the fed paper, becoming fed together with the paper. In such cases, clumps of paper dust may become deposited on the photosensitive drums, on the transfer rollers, or the like, giving rise to diminished image quality. For this reason, paper dust accumulating in the abutting section of the feed roller and the cleaning member must be removed.

SUMMARY OF THE INVENTION

The sheet feeding device according to a first aspect of the present disclosure is provided with a fixed frame and a turning frame. The fixed frame has a drive section and a first feed roller. The turning frame is supported in opening/closing fashion at one end thereof as a turning fulcrum by the fixed frame; and at the closed position forms a sheet feed path in association with the fixed frame, the turning frame exposes the inside of the sheet feed path by turning thereof from the closed position to an open position. The turning frame includes a second feed roller with an integrally rotatable feed gear, a cleaning member, and a transmission gear. The second feed roller at the closed position forms a nip together with the first feed roller, and rotates to feed a sheet. The cleaning member wipes the peripheral surface of the second feed roller. The rotatably supported transmission gear is capable of engaging and disengaging the feed gear. The fixed frame includes a fixed gear. The fixed gear is fixed to the fixed frame, and through turning of the turning frame from the closed position to the open position engages the transmission gear and rotates the transmission gear. The transmission gear disengages from the feed gear when the turning frame is at the closed position; and through turning of the turning frame from the closed position to the open position engages the feed gear, rotating the second feed roller in the opposite direction from that during sheet feeding.

The image forming device according to another aspect of the present disclosure is provided with the aforedescribed sheet feeding device, and a transfer section. The transfer section transfers a toner image to a sheet fed by the sheet feeding device. The first feed roller and the second feed roller constitute a resist roller pair situated upstream side of the transfer section in the sheet feed direction.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment of the present disclosure will be described below, taking the example of a tandem system color laser printer.

As shown inFIG. 1, an image forming device100of the present embodiment feeds paper P (corresponding to the “sheet” of the present disclosure), while printing an image onto the paper P. That is, a sheet feeding device for feeding the paper P is built into the image forming device100.

Specifically, the image forming device100is provided with a paper supply section101, a paper feed section102, an image forming section103, an intermediate transfer section104, a fixing section105, and a manual-feed paper supply section106. As paper feed paths for feeding the paper P, the image forming device100has a first feed path P1, a second feed path P2, and a third feed path P3. Of these, the first feed path P1corresponds to the “sheet feed path” of the present disclosure. The second feed path P2is a reversal feed path for reversing the paper P front to back during duplex printing. The third feed path P3is a manual-feed path for feed of manually-fed paper P.

The paper supply section101includes a paper cassette11into which the paper P is loaded. The paper supply section101supplies the first feed path P1with the paper P loaded in the paper cassette11. This paper supply section101is furnished with a pickup roller12for withdrawing the paper P loaded in the paper cassette11. The paper supply section101is additionally furnished with a paper supply roller pair13, whereby the paper P withdrawn from the paper cassette11is separated into single sheets and supplied to the first feed path P1.

The paper P supplied onto the first feed path P1is fed by the paper feed section102through a transfer nip and a fixation nip, in this order, then discharged into a discharge tray21. This paper feed section102includes a plurality of feed roller pairs22for feeding the paper along the first feed path P1. The feed roller pair22that, of the plurality of feed roller pairs22, is the pair just to the front of the transfer nip, idles the paper P short of the transfer nip, then delivers it to the transfer nip in synchronized fashion to the timing of toner image formation and transfer. In the following description, this feed roller pair22is sometimes designated as a resist roller pair23. The feed roller pair22that, of the plurality of feed roller pairs22, is the pair closest to the discharge tray21rotates in reverse during duplex printing, and guides the paper P to the second feed path P2. In the following description, this feed roller pair22is sometimes designated as a discharge roller pair24.

As shown inFIG. 2, the resist roller pair23is composed of resist rollers23aand23b.The resist roller23ais a driving roller, and rotates through drive power transmitted from a motor M (corresponding to the “drive section”). The resist roller23bis a driven roller which is pressed against the resist roller23ato form a feed nip for feeding the paper P, and is rotated through driving by the resist roller23a(while rotating in the direction A1opposite the direction of rotation of the resist roller23a). Formation of the feed nip constitutes a condition in which paper feed (printing) is enabled, with the paper P being fed by the resist roller pair23as the paper P advances through the feed nip.

The resist roller23ais rotatably supported on a fixed frame111constituting the frame of the device chassis, while the resist roller23bis rotatably supported on a turning frame71constituting the frame of a feed unit107, discussed later. The turning frame71refers to a frame which is attached to the fixed frame111so as to be capable of turning (opening/closing) in a direction A2(the same direction as the rotation direction of the resist roller23bduring paper feed) and in the direction B2opposite the direction A2, about a turning shaft72as the turning fulcrum.

A cleaning member25for cleaning the resist roller23bis furnished in the vicinity of the resist roller23b.The cleaning member25is an elastically deformable member composed of a foamed member of sponge or the like, or of a blade made of resin, which is always in constant abutment against the resist roller23b.In so doing, as the resist roller23brotates, foreign matter200such as paper dust or the like deposited on the resist roller23bis scraped off by the cleaning member25. That is, cleaning of the resist roller23bis performed during paper feed (during printing), when the resist roller23bis rotating in direction A1. A portion of the foreign matter200accumulates in a depression formed in the abutting portion of the cleaning member25and the resist roller23b.The depression in which the foreign matter200gathers is formed through elastic deformation of the abutting portion of the cleaning member25that abuts the resist roller23b.In this configuration, the resist roller23bcorresponds to the “second feed roller” of the present disclosure. That is, the resist roller23acorresponds to the “first feed roller” of the present disclosure.

The foreign matter200scraped off by the cleaning member25drops into a recess75, discussed later, where it accumulates, but in some cases remains accumulated in the abutting section (depression) of the resist roller23band the cleaning member25, without dropping into the recess75.

Returning toFIG. 1, the paper feed section102includes a plurality of reversal roller pairs26for feeding the paper P along the second feed path P2. The paper feed section102further includes a plurality of manual-feed roller pairs27for feeding the paper P along the third feed path P3.

The image forming section103includes toner image forming sections31Bk,31Y,31C, and31M (hereinafter, in some cases designated collectively simply as toner image forming sections31) for forming toner images of the colors black, yellow, cyan, and magenta. The toner image forming sections31each have a photosensitive drum1, an electrostatic device2, a developing device3, and a drum cleaning device4. The image forming section103additionally has an exposure device5for emitting exposure light L to form an electrostatic image on the surface of the photosensitive drum1. Toners of the colors black, yellow, cyan, and magenta are respectively contained in toner containers32Bk,32Y,32C, and32M.

The intermediate transfer section104includes an endless intermediate transfer belt41. To the inside of the intermediate transfer belt41are situated primary transfer rollers42Bk,42Y,42C, and42M (hereinafter, in some cases designated collectively simply as primary transfer rollers42) corresponding to the colors black, yellow, cyan, and magenta, which sandwich the intermediate transfer belt41in relation to the photosensitive drum1of the corresponding color. To the inside of the intermediate transfer belt41are situated a drive roller43and a driven roller44, which, together with the primary transfer rollers42, are spanned by the intermediate transfer belt41. A secondary transfer roller45is situated sandwiching the intermediate transfer belt41in relation to the drive roller43. In so doing, a transfer nip is formed by the intermediate transfer belt41and the secondary transfer roller45.

Through application of transfer voltage to the primary transfer rollers42, the toner images of each color formed by the image forming section103(the toner images on the surfaces of the photosensitive drums1) undergo primary transfer in succession to the intermediate transfer belt41, in superimposed fashion free from misalignment. Thereafter, through application of transfer voltage to the secondary transfer roller45, the toner images produced by primary transfer to the intermediate transfer belt41undergo secondary transfer to the paper P. After the secondary transfer, cleaning of the intermediate transfer belt41is performed by a belt cleaning device46.

The fixing section105applies heat and pressure to fix the toner image transferred to the paper P. This fixing section105includes a heated roller51and a pressure roller52. The heated roller51incorporates a heat source. The pressure roller52is pressed against the heated roller51, forming a fixing nip together with the heating roller51. The paper P to which the toner image has been transferred is then subjected to heat and pressure by being passed through the fixing nip. In so doing, the toner image is fixed onto the paper P, completing printing. The printed paper P is sent to the discharge tray21by the discharge roller pair24. However, when duplex printing is performed, the paper P having passed through the fixing nip (the paper P printed on one side) is sent to the second feed path P2.

In the case of performing duplex printing, a switching claw SC blocks the entrance of advance into the second feed path P2, so that the paper P sent from the fixing section105(the paper P printed on one side) does not advance to the second feed path P2. In so doing, the paper P sent from the fixing section105is guided into the discharge tray21. At this time, the discharge roller pair24initially undergo forward rotation to partially discharge the paper P into the discharge tray21, then undergo reverse rotation before the trailing edge of the paper P pass through. The switching claw SC opens the entrance of advance into the second feed path P2. In so doing, the paper P printed on one side is guided from the trailing edge thereof into the second feed path P2. Thereafter, the paper P printed on one side is fed along the second feed path P2by the reversal roller pair26, reaching the upstream side in the paper feed direction from the resist roller pair24(and is supplied to the first feed path P1). At this time, because the paper P has been reversed front to back, printing is performed on the back face (unprinted face) of the paper P.

The manual-feed paper supply section106includes a manual-feed tray61. The manual-feed tray61is attached in turnable (opening/closing) fashion with respect to the device chassis. In so doing, the manual-feed tray61can be stowed away when the manual-feed tray61is not used (seeFIG. 3).

The manual-feed paper supply section106supplies the paper P placed on the manual-feed tray61to the third feed path P3. The manual-feed paper supply section106is furnished with a pickup roller62for withdrawing the paper P placed on the manual-feed tray61. The manual-feed paper supply section106is additionally furnished with a paper supply roller pair63whereby the paper P withdrawn from the manual-feed tray61is separated into single sheets and supplied to the third feed path P3. In so doing, the paper P supplied to the third feed path P3, fed by the manual-feed roller pairs27, reaches the resist roller pair23(and is supplied to the first feed path P1).

As shown inFIG. 1andFIG. 3, a wall portion positioned to the second feed path P2side of the image forming device100is constituted by a device cover100CV attached in turnable (opening/closing) fashion with respect to the device chassis. This device cover100CV holds a reversal roller26a,which is one of reversal rollers26aand26bthat constitute the reversal roller pair26. The device cover100CV is closed during paper feed (during printing) (the state shown inFIG. 1). On the other hand, when the device cover100CV is open (the state shown inFIG. 3), the second feed path P2is exposed (the feed unit107, discussed later, is exposed). Consequently, in cases in which a paper jam has occurred on the second feed path P2, the device cover100CV can be opened in order to easily perform a jam treatment procedure to clear the jam. Paper feed (printing) is not performed with the device cover100CV open.

As shown inFIG. 3, the feed unit107which is exposed by opening the device cover100CV is a unit constituted inter alia by the reversal roller26b,the resist roller23b,the cleaning member25, and the secondary transfer roller45. Specifically, as shown inFIG. 4, the members constituting the feed unit107(the reversal roller26b, the resist roller23b,the cleaning member25, the secondary transfer roller45, and so on) are attached to the turning frame71, and constituted as a unit thereby. The reversal roller26b,the resist roller23b,and the secondary transfer roller45are rotatably supported by the turning frame71.

The turning frame71has the turning shaft72situated at one end thereof. This turning shaft72is supported by fitting into mating holes112(seeFIG. 5) furnished to the fixed frame111. In so doing, as shown inFIG. 2, the turning frame71is turnable (opening/closing) in the direction A2(the same direction as the rotation direction of the resist roller23bduring paper feed) and in the direction B2opposite the direction A2, about the turning shaft72as the turning fulcrum. That is, the feed unit107is turnable in the direction A2and the direction B2. In the following description, the turn position of the feed unit107when the feed unit107has not been turned in the direction A2is designated as the closed position. The limit position for turning of the feed unit107towards the direction A2is, for example, a position turned by approximately 90° from the closed position in the direction A2. In the following description, the turning position of the feed unit107when the feed unit107has been turned by approximately 90° in the direction A2is designated as the open position.

With the feed unit107held in the closed position, the resist roller23bpresses against the resist roller23a,forming the feed nip, while the secondary transfer roller45presses against the intermediate transfer belt41, forming the transfer nip (the state inFIG. 2). The first feed path P1is then formed by the turning frame71and the fixed frame111. That is, the closed position refers to the position at which paper feed is possible.

When the feed unit107is turned from the closed position to the open position, the resist roller23bseparates from the resist roller23a,and the secondary transfer roller45separates from the intermediate transfer belt41(the state inFIG. 8andFIG. 10). The inside of the first feed path P1is then exposed. Consequently, in cases in which a paper jam has occurred on the first feed path P1, a jam treatment procedure to clear the jam can be performed easily, by turning the feed unit107from the closed position to the open position.

As shown inFIG. 5, a gear-forming part113having the mating hole112as the gear center is fixed in non-rotating state on the fixed frame111. This gear-forming part113is a sector gear having a plurality of gear teeth arrayed along part of a circle (an arc) centered on the mating hole112(the turning fulcrum of the turning frame71). The gear-forming part113may also be, for example, one having a plurality of gear teeth arrayed along the entire circumference of a circle centered on the mating hole112. Where the fixed frame111is made of resin, the gear-forming part113may be integrally molded with the fixed frame111, in order to reduce the number of parts. The gear-forming part113corresponds to the “fixed gear” of the present disclosure.

As shown inFIG. 4, a resist gear73that rotates in unison together with the resist roller23bin the same direction as the resist roller23bis rotatably supported by the turning frame71. This resist gear73is furnished to an end part of the rotation shaft of the resist roller23b.The resist gear73corresponds to the “feed gear” of the present disclosure.

An incompletely-toothed gear74having a missing portion74afrom which gear teeth are missing is also rotatably supported by the turning frame71. This incompletely-toothed gear74is situated between the resist gear73and the gear-forming part113, in such a way as to constantly mesh with the gear-forming part113when the turning frame71is turnably supported on the fixed frame111. The incompletely-toothed gear74corresponds to the “transmission gear” of the present disclosure.

As shown inFIG. 6, with the feed unit107(the turning frame71) held in the closed position, the gear-forming part113meshes with (engages) the incompletely-toothed gear74. On the other hand, the resist gear73, by virtue of facing the missing portion74a,does not mesh with (does not engage) the incompletely-toothed gear74. In so doing, rotation of the resist roller23bin the direction A1during paper feed is unimpaired. That is, during paper feed, as shown inFIG. 2, the resist roller23b,driven by the resist roller23a,rotates in the direction A1. Through rotation of the resist roller23bin the direction A1, foreign matter D deposited onto the resist roller23bis scraped off by the cleaning member25. The foreign matter200then drops into and accumulates in the recess75, discussed later. Alternatively, the foreign matter may accumulate in the contacting section (depression) of the resist roller23band the cleaning member25, without dropping into the recess75.

On the other hand, as shown inFIG. 7, when the feed unit107(the turning frame71) is turned from the closed position towards the open position, the resist gear73and the incompletely-toothed gear74, together with the turning frame71, turn about the turning shaft72as the turning fulcrum. The incompletely-toothed gear74constantly meshes with the gear-forming part113. The gear-forming part113is fixed in non-rotating state to the fixed frame111. Consequently, as the feed unit107(the turning frame71) turns from the closed position towards the open position, the incompletely-toothed gear74, due to meshing thereof with the gear-forming part113, rotates in the direction A1(the position of the missing portion74awith respect to the resist gear73shifts in the direction A1). As the feed unit107continues to turn from the closed position towards the open position, the resist gear73meshes with (engages) the incompletely-toothed gear74rotating in the direction A1. In so doing, the resist gear73begins to rotate in the direction B1. In so doing, as shown inFIG. 8, the resist roller23brotates in the direction B1together with the resist gear73. Then, as the feed unit107(the turning frame71) turns from the closed position towards the open position, the state shown inFIG. 9andFIG. 10is produced.

As shown inFIG. 8andFIG. 10, as the feed unit107(the turning frame71) turns from the closed position towards the open position, the contacting section (depression) of the resist roller23band the cleaning member25, where the foreign matter200has accumulated, gradually heads downward. At this time, the resist roller23bis rotating in the direction B1. In so doing, the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25is scraped away by the resist roller23brotating in the direction B1, and falls downward.

However, as shown inFIG. 11, when for example a portion of the turning frame71approaches the contacting section of the resist roller23band the cleaning member25, the foreign matter200accumulated in the contacting section (depression) of the resist roller23band the cleaning member25cannot fall downward. For this reason, the turning frame71has been furnished with the recess75for the purpose of receiving the falling foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25, when the turning frame71has turned from the closed position towards the open position as shown inFIG. 8andFIG. 10. The recess75is designed such that the opening of the recess75is situated below the cleaning member25when the turning frame71has turned from the closed position to the open position. The recess75is constructed in such a way that foreign matter having accumulated in the recess75does not spill out when the turning frame71is held at the closed position.

As described above, the image forming device100(sheet feeding device) of the present embodiment is provided with the fixed frame111having the motor M (drive section) and the resist roller23b(first feed roller); and with the turning frame71which is supported in opening/closing fashion at one end thereof as the turning fulcrum by the fixed frame111, and which at the closed position forms the first feed path P1(sheet feed path) in association with the fixed frame111, the inside of the first feed path P1being exposed through turning thereof from the closed position to an open position. The turning frame71includes the resist roller23b(second feed roller) which includes the integrally rotatable resist gear73(feed gear), and which at the closed position forms a nip together with the resist roller23aat the closed position, and feeds the paper P (sheet) through rotation thereof; the cleaning member25which wipes against the peripheral surface of the resist roller23b;and the rotatably supported, incompletely-toothed gear74(transmission gear) capable of engaging and disengaging the resist gear73. The fixed frame111includes the gear-forming part113(fixed gear) which is fixed to the fixed frame111, and which through turning of the turning frame71from the closed position to the open position engages the incompletely-toothed gear74and rotates the incompletely-toothed gear74. The incompletely-toothed gear74disengages from the resist gear73when the turning frame71is at the closed position, and through turning of the turning frame71from the closed position to the open position, rotates to engage the resist gear73, rotating the resist roller23bin the opposite direction from that during sheet feeding.

According to the configuration of the present embodiment, the inside of the first feed path P1is exposed through turning of the turning frame71from the closed position (the position of forming the first feed path P1in association with the fixed frame111) to the open position. Consequently, when a paper jam has occurred on the first feed path P1, the turning frame71is turned from the closed position towards the open position, in order to perform a jam treatment procedure to clear the jam on the first feed path P1. At this time, in association with turning of the turning frame71from the closed position towards the open position, the resist roller23brotates in the direction B1which is the opposite of the direction A1(the direction of rotation during feeding of the paper P to the downstream side). Therefore, despite the foreign matter200scraped off by the cleaning member25as the resist roller23brotates in the direction A1having accumulated in the contacting section of the resist roller23band the cleaning member25, the foreign matter200is scraped away by the resist roller23brotating in the direction B1.

In so doing, when the turning frame71is turned from the closed position to the open position in order to perform a jam treatment procedure, the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25is removed. Consequently, the need for a special procedure in order to remove the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25is obviated. When the jam treatment procedure is performed (when the turning frame71is turned from the closed position to the open position), the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25is removed, and therefore situations in which the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25is left there can be avoided.

The resist roller23bis a feed roller situated to the upstream side in the paper feed direction from the transfer nip, the feed roller contacting the fed paper P at a point just before reaching the transfer nip. Consequently, by cleaning the resist roller23bwith the cleaning member25and removing the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25, situations in which the foreign matter200is fed through the transfer nip together with the paper P and becomes deposited on the secondary transfer roller45can be avoided. In so doing, diminished image quality caused by deposition of the foreign matter200on the secondary transfer roller45can be minimized.

Moreover, in the present embodiment, in the aforedescribed manner, the turning frame71is provided with the recess75for the purpose of receiving the falling foreign matter200scraped off by the cleaning member25(the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25) when the turning frame71is turned from the closed position to the open position. According to this configuration, when the turning frame71has turned from the closed position to the open position, the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25will fall, whereby the foreign matter200accumulated in the contacting section of the resist roller23band the cleaning member25can easily be removed. Moreover, because the foreign matter200falling from the contacting section of the resist roller23band the cleaning member25is received in the recess75, the foreign matter200does not scatter about the surrounding area.

Additionally, according to the present embodiment, in the aforedescribed manner, the recess75is furnished to the turning frame71in such a way that the opening of the recess75is situated below the cleaning member25when the turning frame71is turned from the closed position to the open position. According to this configuration, the foreign matter200can be made to fall into the recess75in a reliable manner, when the turning frame71is turned from the closed position to the open position.

Additionally, according to the present embodiment, in the aforedescribed manner, the fixed frame111is made of resin. The gear-forming part113is integrally molded with the fixed frame111. According to this configuration, an increase in the number of parts can be avoided.

The embodiments disclosed herein are in all respects merely exemplary, and should not be construed as limiting. The scope of the present disclosure is shown by the claims and not by the foregoing description of the embodiments, and all modifications equivalent in significance within the scope of the claims are encompassed therein.