Patent ID: 12214980

DESCRIPTION OF THE EMBODIMENTS

The embodiments of the present disclosure will be described below with reference to the drawings.

First Embodiment

(Image Forming Apparatus)

An image forming apparatus101configured to form an image on a recording medium P will be described with reference toFIG.1.FIG.1is a cross-sectional view of the image forming apparatus101. In the following description, a position facing an operation portion11with which a user performs various inputs/settings to the image forming apparatus101is referred to as a “front side” of the image forming apparatus101, and a position opposite to the position on the front side is referred to as a “rear side.”FIG.1shows an internal structure of the image forming apparatus101as seen from the front side. In the following description, as an example of the image forming apparatus101, a copying machine that reads an image of a document and forms the image on a recording medium P using an electrophotographic method will be described. However, the image forming apparatus101is not limited to the electrophotographic copying machine, and may be a facsimile, a printer, a color copying machine, or a multifunction peripheral thereof, or may be an image forming apparatus that forms an image on a recording medium P using an inkjet method.

As shown inFIG.1, the image forming apparatus101is provided with an image forming apparatus main body101A and an image reading apparatus103provided on an upper portion of the image forming apparatus main body101A. The image reading apparatus103as an example of a sheet processing apparatus is provided with an automatic document feeder (document conveying apparatus)1and a scanner portion30. The scanner portion30is provided with an image reading portion A as an example of a processing portion. The automatic document feeder1automatically feeds a document (sheet) D placed on a document tray2to the image reading portion A of the scanner portion30and discharges the document D read by the image reading portion A to a discharge tray3. The document tray2and the discharge tray3constitute a document stacking device12on which documents are stacked. The documents D to be fed to the image reading portion (processing portion) A are stacked on the document tray2. The discharge tray3is disposed below the document tray2. When viewed from above, the document tray2and the discharge tray3overlap at least partially.

The image reading portion A receives a reflected light of a light irradiated on the document D conveyed to an image reading position and converts an amount of received light into an electrical signal to read an image of the document D optically. Image data (image reading information) is generated based on the electrical signal of the image reading portion A. The image data is input to a controller132provided in the image forming apparatus main body101A. The controller132controls the image forming apparatus101.

The image forming apparatus main body101A includes an image forming portion133configured to form a toner image on a recording medium P using the electrophotographic method and a recording medium conveying portion34configured to convey the recording medium P to the image forming portion133. The image forming portion133has a photosensitive drum121rotatable along a conveying direction of the recording medium P. A charger118, an exposure device123, a developing device124, a transfer charger125, a separation charger126, and a cleaner127are disposed around the photosensitive drum121. The charger118uniformly charges a surface of the photosensitive drum121which is rotating. The exposure device123forms an electrostatic latent image on the surface of the photosensitive drum121based on the image data from the image reading apparatus103. The developing device124develops the electrostatic latent image into a toner image with toner (developer).

The image forming apparatus main body101A is provided with recording medium stacking portions137a,137b,137c, and137din which various sizes of recording media P are stored. The recording media P stored in the recording medium stacking portions137ato137dare fed out one by one by the corresponding feeding rollers32, respectively, and delivered to the corresponding conveying rollers33aand separation rollers33b. A manual feed tray137eon which the recording media P are stacked is provided on a right side of the image forming apparatus main body101A. The recording medium P stacked on the manual feed tray137eis fed by a pair of separation feeding rollers138. The recording medium P fed from any of the recording medium stacking portions137ato137dor the manual feed tray137eis fed by a pair of conveying rollers131to a pair of registration rollers136.

The pair of registration rollers136corrects a skew feed of the recording medium P. The pair of registration rollers136conveys the recording medium P to a transfer position so that a leading edge of the recording medium P coincides with a leading edge of the toner image on the photosensitive drum121at the transfer position between the photosensitive drum121and the transfer charger125. The transfer charger125transfers the toner image on the photosensitive drum121to the recording medium P. The separation charger126separates the recording medium P from the photosensitive drum121. The cleaner127removes toner remaining on the surface of the photosensitive drum121after transferring the toner image to the recording medium P.

The recording medium P onto which the toner image has been transferred is conveyed to a fixing portion129by a belt conveying portion128. The fixing portion129heats and pressurizes the recording medium P to fix the toner image to a surface of the recording medium P so that the image is formed on the recording medium P. The recording medium P on which the image is formed is discharged to a discharge tray130outside the image forming apparatus main body101A by a pair of discharge rollers40.

(Image Reading Apparatus)

Next, the image reading apparatus103as an example of a document processing apparatus will be described with reference toFIG.2.FIG.2is a cross-sectional view of the image reading apparatus103. The image reading apparatus103is disposed on the upper portion of the image forming apparatus101. However, the image reading apparatus103may be configured as a single unit, such as a flatbed scanner with the automatic document feeder1. It should be noted that the dimensions, materials, shapes, and relative arrangements of the components described in the following descriptions are not intended to limit the scope of the disclosure to them only, unless otherwise specified.

A feeding portion of the automatic document feeder1is provided with a feeding roller (feeding member)4, a feeding roller5, and a separation roller6urged against the feeding roller5by a spring. The feeding roller4is lowered from the dotted position to the solid position as shown inFIG.2, contacts the document D placed on the document tray2, and conveys the document D to an inlet side conveyance path space of the feeding portion in a feeding direction CD. In the feeding portion, the document D conveyed to the feeding roller5by the feeding roller4is separated one by one by a friction force between the feeding roller5and the separation roller6. The separated document D is conveyed by the feeding roller5so that a leading edge of the document D abuts against a pair of registration rollers7which has stopped rotating. Since the document D continues to be conveyed by the feeding roller5while the pair of registration rollers7has stopped, a loop is formed in the document D to correct the skew feed of the document D. When the rotation of the pair of registration rollers7is started, the document D of which the skew feed is corrected is conveyed to a pair of conveying rollers8by the pair of registration rollers7. The document D is conveyed to the image reading portion A by the pair of conveying rollers8. The image reading portion A has a front surface line sensor151configured to read an image on a front surface of the document D and a back surface line sensor201configured to read an image on a back surface of the document D. While the images on both surfaces of the document D are read by the front surface line sensor151and the back surface line sensor201, the document D is conveyed by a pair of conveying rollers9to a pair of discharge rollers (discharge member)10. The pair of discharge rollers10sequentially discharges the document D to stack it on a document stacking surface of the discharge tray3. In the embodiment, the pair of registration rollers7, the pair of conveying rollers8, and the pair of conveying rollers9constitute a conveying portion.

FIG.3is a perspective view of the automatic document feeder1as seen from a right oblique front side.FIG.4is a perspective view of the automatic document feeder1as seen from a right oblique rear side. The document tray2is provided with a front side regulation guide (first regulating member)24configured to regulate one side edge of the document in a width direction WD orthogonal to the feeding direction CD and a rear side regulation guide (second regulating member)26configured to regulate the other side edge opposite to the one side edge of the document. The document tray2is provided with a first upper document tray21, a second upper document tray22, and a telescopic tray (movable tray member)25. The first upper document tray21and the second upper document tray22construct an upper tray member configured to support a lower surface of the document to be placed on the document tray2. In the embodiment, a rear side regulation guide26is provided on the first upper document tray21. A front side regulation guide24is provided on the telescopic tray25. The rear side regulation guide26and the front side regulation guide24are configured to be movable in conjunction with each other in the width direction WD with respect to the document tray2.

The rear side regulation guide26is provided with a rear side stacking surface261configured to support a lower surface of the other side edge of the document in a stacking direction SD of the documents and a rear side regulating surface262configured to regulate the other side edge of the document in the width direction WD. The front side regulation guide24is provided with a front side stacking surface241configured to support a lower surface of the one side edge of the document in the stacking direction SD of the documents and a front side regulating surface242configured to regulate the one side edge of the document in the width direction WD. The document tray2supports the documents in the stacking direction SD by stacking the documents on the rear side stacking surface261provided on the rear side regulation guide26, the front side stacking surface241provided on the front side regulation guide24, the telescopic tray25, the first upper document tray21, and the second upper document tray22. The documents stacked on the document tray2are aligned in the width direction WD and both edges of the documents are regulated by the rear side regulating surface262provided on the rear side regulation guide26and the front side regulating surface242provided on the front side regulation guide24.

FIG.5AandFIG.5Bare views of the document tray2in the first embodiment when a small number of documents are fed.FIG.5Ais a perspective view of the document tray2when the small number of documents are fed.FIG.5Bis a cross-sectional view of the document tray2taken along the line VB-VB inFIG.5A. The documents D are stacked on the rear side stacking surface261, the front side stacking surface241, the telescopic tray25, the first upper document tray21, and the second upper document tray22. The first upper document tray21is supported rotatably with respect to a lower document tray (lower tray member)23. The second upper document tray22is fixed to the lower document tray23. The automatic document feeder1is provided with a lifter50as a raising and lowering device configured to raise and lower the first upper document tray21. The lifter50includes a motor M as a driving portion, a rotation shaft501which is rotated by the motor M, and a lifter plate502connected to the rotation shaft501and configured to be rotated integrally with the rotation shaft501. When the rotation shaft501is rotated by a driving force from the motor M, the lifter plate502is rotated around the rotation shaft501and brought into contact with the first upper document tray21to raise the first upper document tray21. The first upper document tray21is brought close to the feeding roller4. The first upper document tray21is rotated around a point C with respect to the lower document tray23by the lifter plate502, a downstream end portion of the first upper document tray21in the feeding direction CD is raised, and the document D is fed in contact with the feeding roller4. By a reverse rotation of the motor M, the first upper document tray21is moved away from the feeding roller4.

FIG.6is a perspective view of the document tray2as seen from the discharge tray3. The first upper document tray21(not shown inFIG.6), the second upper document tray22, the front side regulation guide24, and the rear side regulation guide26(not shown inFIG.6) are covered from the lower side by the lower document tray23. The telescopic tray25is covered from the lower side by a telescopic tray cover (tray cover)28. The telescopic tray cover28is configured to be movable in the width direction WD integrally with the telescopic tray25.

FIG.7A,FIG.7B, andFIG.7Care views of the first upper document tray21, the telescopic tray25, the front side regulation guide24, and the rear side regulation guide26.FIG.7Ais a view of the first upper document tray21, the telescopic tray25, the front side regulation guide24, and the rear side regulation guide26before assembly.FIG.7Bis a view of the first upper document tray21, the telescopic tray25, the front side regulation guide24, and the rear side regulation guide26after assembly.FIG.7Cis a cross-sectional view taken along the line VIIC-VIIC inFIG.7B. The front side regulation guide24and the telescopic tray25are disposed so as to sandwich the first upper document tray21, and are connected by a fixing member271to be integrally movable in the width direction WD. The front side regulation guide24is movable above an upper surface of the first upper document tray21, and the telescopic tray25is movable below a lower surface of the first upper document tray21.

A guide member52is connected to the first upper document tray21so that the telescopic tray25is sandwiched between the guide member52and the first upper document tray21. The rear side regulation guide26and a guide rack27are disposed so as to sandwich the first upper document tray21, and are connected by a fixing member272so that the rear side regulation guide26and the guide rack27are configured to be movable in the width direction WD as a unit. A protrusion263provided on the rear side regulation guide26is disposed in a slit212provided in the first upper document tray21. The protrusion263is movable in the width direction WD along the slit212and functions as a guide for the movement of the rear side regulation guide26in the width direction WD.

A connecting member51is rotatably connected to a shaft211provided on the first upper document tray21. The connecting member51is disposed to be sandwiched between the telescopic tray25and the guide rack27. Gear teeth51aprovided on the connecting member51mesh with gear teeth25aprovided on the telescopic tray25and gear teeth27aprovided on the guide rack27. With this, the rear side regulation guide26and the front side regulation guide24are configured to be movable in association with each other in the width direction WD with respect to the document tray2.

FIG.8A,FIG.8B,FIG.8C, andFIG.8Dare explanatory views of the movement of the rear side regulation guide26and the front side regulation guide24.FIG.8AandFIG.8Care perspective views as seen from below in the stacking direction SD of the documents.FIG.8BandFIG.8Dare perspective views as seen from above in the stacking direction SD of the documents. When large-size documents are stacked on the document tray2, the rear side regulation guide26and the front side regulation guide24are moved in association with each other so as to be separated from each other as shown inFIG.8AandFIG.8B. When small-size documents are stacked on the document tray2, the rear side regulation guide26and the front side regulation guide24are moved in association with each other so as to be moved closer to each other as shown inFIG.8CandFIG.8D. When the small-size documents are stacked on the document tray2, the telescopic tray25is retracted under the first upper document tray21to form a space SP through which the user can easily see the discharge tray3.

FIG.9AandFIG.9Bare perspective views of the lower document tray23and the telescopic tray cover28.FIG.9Ais a perspective view of the lower document tray23and the telescopic tray cover28before assembly.FIG.9Bis a perspective view of the lower document tray23and the telescopic tray cover28after assembly. A guide member53is connected to the lower document tray23so as to sandwich the telescopic tray cover28between the guide member53and the lower document tray23. A hooking portion281provided on the telescopic tray cover28is disposed so as to be caught by a rail portion231provided on the lower document tray23. Thus, the telescopic tray cover28is configured to be movable in the width direction WD with respect to the lower document tray23.

FIG.10A,FIG.10B, andFIG.10Care views of the telescopic tray25in the first embodiment.FIG.10Ais a perspective view of the telescopic tray25.FIG.10Bis an enlarged view of a mounting claw251.FIG.10Cis an enlarged view of a mounting hole252. In the telescopic tray25, the gear teeth25aare provided at a side end portion of the telescopic tray25on the downstream side in the feeding direction CD of the document. In the telescopic tray25, the mounting claw251and the mounting hole252are provided on an end portion25bof the telescopic tray25on the front side of the image forming apparatus101in the width direction WD. The mounting claw251is provided with a shaft portion251aand a hooking portion251bprovided on a tip portion of the shaft portion251a.

FIG.11A,FIG.11B,FIG.11C, andFIG.11Dare views of the telescopic tray cover28in the first embodiment.FIG.11Ais a perspective view of the telescopic tray cover28.FIG.11Bis a partial view of the vicinity of a mounting claw282.FIG.11Cis a partial enlarged view of a first guide rib283and a second guide rib284.FIG.11Dis a partial cross-sectional view of the telescopic tray cover28as seen from above in the stacking direction SD of the documents. The telescopic tray cover28has a wall portion286extending from a bottom portion28bof the telescopic tray cover28in the stacking direction SD at an end portion28aof the telescopic tray cover28on the front side of the image forming apparatus101in the width direction WD. The wall portion286has the mounting claw282at an end portion286aon the upstream side in the feeding direction CD of the document. The wall portion286has the first guide rib283and the second guide rib284at an end portion286bon the downstream side in the feeding direction CD of the document. The mounting claw282has a shaft portion282aand a hooking portion282bprovided at a tip portion of the shaft portion282a. The first guide rib283and the second guide rib284are disposed on their respective arcs around the mounting claw282. A slit (groove portion)285is provided between the second guide rib284and the wall portion286.

FIG.12A,FIG.12B,FIG.12C, andFIG.12Dare views of the telescopic tray25and the telescopic tray cover28in the first embodiment.FIG.12Ais a perspective view of the telescopic tray25and the telescopic tray cover28before assembly.FIG.12Bis a perspective view of the telescopic tray25and the telescopic tray cover28after assembly.FIG.12Cis an enlarged cross-sectional view of the mounting claw282locked to the mounting hole252.FIG.12Dis an enlarged cross-sectional view of the mounting claw251locked to the second guide rib284. The mounting claw (protrusion)251of the telescopic tray25is inserted between the first guide rib283and the second guide rib284of the telescopic tray cover28, and the hooking portion251bof the mounting claw251is caught by the second guide rib284in the slit285. The mounting claw282of the telescopic tray cover28is inserted into the mounting hole252of the telescopic tray25, and the hooking portion282bof the mounting claw282is caught by an inside surface254of the telescopic tray25. Thus, the telescopic tray25is connected to the telescopic tray cover28. Since the hooking portion251bof the mounting claw251is caught by the second guide rib284in the slit285and the hooking portion282bof the mounting claw282is caught by the inside surface254of the telescopic tray25, the movement of the telescopic tray25with respect to the telescopic tray cover28in the width direction WD is regulated. The shaft portion282aof the mounting claw282is held rotatably with respect to the mounting hole252. The hooking portion251bof the mounting claw251is movable in the slit (groove portion)285between the second guide rib284and the wall portion286. With this, the telescopic tray25is configured to be rotatable with respect to the telescopic tray cover28around the mounting hole (first rotation supporting point)252.

FIG.13AandFIG.13Bare explanatory views of the rotation of the telescopic tray25with respect to the telescopic tray cover28in the first embodiment. InFIG.13A, the telescopic tray25is rotated downward with respect to the telescopic tray cover28to be in a lowered position DP. InFIG.13B, the telescopic tray25is rotated upward in the stacking direction SD with respect to the telescopic tray cover28to be in a raised position UP. When the telescopic tray25is rotated upward in the stacking direction SD with respect to the telescopic tray cover28, an air gap V (gap) is created between the telescopic tray25and the telescopic tray cover28. The wall portion286is extended upward from the bottom portion28bof the telescopic tray cover28in the stacking direction SD so as to cover the air gap V from the front side of the image forming apparatus101.

FIG.14AandFIG.14Bare views of the first upper document tray21and the lower document tray23in the first embodiment.FIG.14Ais a perspective view of the first upper document tray21and the lower document tray23before assembly as seen from the left oblique rear side.FIG.14Bis a perspective view of the first upper document tray21and the lower document tray23before assembly as seen from the left oblique front side. A mounting shaft213provided on the first upper document tray21is inserted into a mounting hole (second rotation supporting point)233provided in the lower document tray23. The mounting shaft213corresponds to the point C shown inFIG.5B. Thus, the first upper document tray21is configured to be rotatable around the point C (FIG.5B) with respect to the lower document tray23. At this time, the mounting hole233is positioned at the same position as the mounting hole252(FIG.10A) of the telescopic tray25in the feeding direction CD and in the stacking direction SD. That is, the mounting hole233of the lower document tray23as the second rotation supporting point is coaxially disposed in line with the mounting hole252of the telescopic tray25as the first rotation supporting point.

The guide member52is fixed to the lower surface of the first upper document tray21. InFIG.14AandFIG.14B, for purposes of illustration, the guide member52is separated from the first upper document tray21. The guide member52is provided with two mounting shafts521. A shutter (cover member)54is provided with mounting holes541in upper portions of both end portions in the longitudinal direction, respectively. Two mounting shafts521of the guide member52are inserted into the two mounting holes541of the shutter54, respectively. With this, the shutter54is held rotatably with respect to the guide member52. The shutter54is connected rotatably with respect to the first upper document tray21via the guide member52. The shutter54is provided with mounting shafts (protrusions)542in lower portions of both end portions in the longitudinal direction, respectively. The lower document tray23is provided with two guide portions232. The two guide portions232are provided with groove holes232aextending in the feeding direction CD, respectively. The two mounting shafts542of the shutter54are inserted into the groove holes232ain the two guide portions (rail portions)232of the lower document tray23, respectively. With this, the two mounting shafts542on the lower end portion of the shutter54are held movably in the feeding direction CD by the groove holes232aof the guide portions232.

FIG.15A,FIG.15B,FIG.15C,FIG.15D, andFIG.15Eare explanatory views of the rotation of the first upper document tray21with respect to the lower document tray23in the first embodiment.FIG.15Ais a perspective view as seen from the left oblique rear side when the first upper document tray21is in the lowered position DP without upward rotation.FIG.15Bis a perspective view as seen from the left oblique rear side when the first upper document tray21is in the raised position UP with upward rotation.FIG.15Cis a perspective view as seen from the right oblique front side when the first upper document tray21is in the raised position UP with upward rotation. As shown inFIG.15A, when the first upper document tray21is in the lowered position DP without upward rotation in the stacking direction SD, the shutter54is stored between the first upper document tray21and the lower document tray23. As shown inFIG.15B, when the first upper document tray21is rotated from the lowered position DP to the raised position UP, the shutter54is rotated and raised in such a manner that the lower end portion of the shutter54is moved along the groove holes232aof the guide portions232to the upstream side in the feeding direction CD. When the first upper document tray21is in the raised position UP, the shutter54is raised and is exposed between the first upper document tray21and the lower document tray23. At this time, the shutter54covers an air gap G (gap) created between the first upper document tray21and the lower document tray23on the upstream side in the feeding direction CD within a range RA in which the wall portion286of the telescopic tray cover28is moved in the width direction WD between a pullout position (first position) PP and a retracted position (second position) RP. The pullout position PP and the retracted position RP will be described later with reference toFIG.16AandFIG.16B. That is, when the first upper document tray21, the telescopic tray25, the front side regulation guide24, and the rear side regulation guide26are in the raised position UP and the front side regulation guide24and the telescopic tray25are in the retracted position RP, the air gap G (gap) is created. The shutter54covers the air gap G (gap) created between the first upper document tray21and the lower document tray23on the downstream side of the telescopic tray25in the feeding direction CD. The lower document tray23is provided with a wall portion234extending upward in the stacking direction SD from a bottom portion23bof the lower document tray23on an end portion23aon the front side of the image forming apparatus101in the width direction WD. The wall portion234covers an air gap0(gap) created between the first upper document tray21and the lower document tray23on the front side in the width direction WD.

FIG.15Dis a cross-sectional view taken along line XVD-XVD inFIG.15B.FIG.15Eis a cross-sectional view taken along line XVE-XVE inFIG.15B. As shown inFIG.15D, when the first upper document tray21is in the raised position UP, an inclined portion543(first abutment portion) provided on the shutter54contacts (abuts) an inclined portion522(second abutment portion) provided on the guide member52. At this time, an angle θ formed by the shutter54and the lower document tray23on the upstream side in the feeding direction CD of the document is an acute angle. Therefore, when the first upper document tray21is rotated downward in the direction away from the feeding roller4, the mounting shafts542of the shutter54can move in the groove holes232aof the guide portions232without resistance. Moreover, when the first upper document tray21is in the raised position UP as shown inFIG.15E, the mounting shafts542are in contact with inclined surfaces (regulating surfaces)2321of the groove holes232a. Therefore, even if the shutter54receives a force (external force) from the upstream side in the feeding direction CD, the shutter54does not rotate.

FIG.16AandFIG.16Bare perspective views of the automatic document feeder1in the first embodiment when large-size documents are fed.FIG.16Ais a perspective view of the automatic document feeder1when a large number of large-size documents are fed.FIG.16Bis a perspective view of the automatic document feeder1when a small number of large-size documents are fed. When the large-size documents are fed, the front side regulation guide24, the telescopic tray25, and the telescopic tray cover28are integrally pulled out to the pullout position PP on the front side in the width direction WD as shown inFIG.16AandFIG.16B. In the pullout position PP, the telescopic tray25can support the under surface of the large-size document together with the first upper document tray21. When the large number of large-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are positioned in the lowered position DP as shown inFIG.16A. In the lowered position DP, the large-size documents are separated from the feeding roller4. When the small number of large-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are integrally raised upward in the stacking direction SD and positioned in the raised position UP as shown inFIG.16Bto enable the large-size documents to be fed. In the raised position UP, the large-size document abuts against the feeding roller4. The wall portion286of the telescopic tray cover28covers the air gap V (FIG.13B) created between the telescopic tray25and the telescopic tray cover28. The wall portion286prevents foreign matter from entering through the air gap V and also prevents a user from getting the user's finger caught between the telescopic tray25and the telescopic tray cover28from the air gap V.

FIG.17AandFIG.17Bare perspective views of the automatic document feeder1in the first embodiment when small-size documents are fed.FIG.17Ais a perspective view of the automatic document feeder1when a large number of small-size documents are fed.FIG.17Bis a perspective view of the automatic document feeder1when a small number of small-size documents are fed. When the small-size documents are fed, the front side regulation guide24, the telescopic tray25, and the telescopic tray cover28are integrally retracted to the retracted position RP on the rear side in the width direction WD as shown inFIG.17AandFIG.17B. In the retracted position RP, the telescopic tray25is retracted below the first upper document tray21to expose a portion of the upper surface of the discharge tray3. This improves the visibility of the small-size documents discharged on the discharge tray3. When the large number of small-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are positioned in the lowered position DP as shown inFIG.17A. In the lowered position DP, the small-size documents are separated from the feeding roller4. When the small number of small-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are integrally raised upward in the stacking direction SD and positioned in the raised position UP as shown inFIG.17Bto enable the small-size documents to be fed. In the raised position UP, the small-size document abuts against the feeding roller4. The wall portion286of the telescopic tray cover28covers the air gap V (FIG.13B) created between the telescopic tray25and the telescopic tray cover28. The shutter54is raised to cover the air gap G (FIG.15C) created between the first upper document tray21and the lower document tray23. With this, the shutter54prevents foreign matter from entering through the air gap G and also prevents a user from getting the user's finger caught between the first upper document tray21and the lower document tray23from the air gap G.

According to the first embodiment, the shutter54is provided to cover the air gap G created between the first upper document tray21and the lower document tray23when the first upper document tray21is moved to the raised position UP in a state in which the telescopic tray25is retracted below the first upper document tray21. Therefore, foreign matter can be prevented from entering the inside of the document stacking device12from the air gap G that is created between the first upper document tray21and the lower document tray23. According to the first embodiment, foreign matter can be prevented from entering the inside of the document tray2.

Second Embodiment

The second embodiment will be described below. In the second embodiment, the same structures as in the first embodiment are denoted by the same reference symbols and the explanations thereof are omitted. Since the image forming apparatus101in the second embodiment has the same structure as in the first embodiment, the explanation thereof is omitted. Since the scanner portion30of the image reading apparatus103in the second embodiment has the same structure as in the first embodiment, the explanation thereof is omitted. The automatic document feeder1of the image reading apparatus103in the second embodiment has different shutters (first shutter55and second shutter56) from the shutter54in the first embodiment. Hereafter, the differences from the first embodiment will be mainly described.

FIG.18AandFIG.18Bare views of the first upper document tray21and the lower document tray23in the second embodiment.FIG.18Ais a perspective view of the first upper document tray21and the lower document tray23before assembly as seen from the left oblique rear side.FIG.18Bis a perspective view of the first upper document tray21and the lower document tray23before assembly as seen from the left oblique front side. The shutter in the second embodiment includes a first shutter (first cover member)55and a second shutter (second cover member)56. The first shutter55is provided with mounting holes551in upper portions of both end portions in the longitudinal direction (width direction WD), respectively. Two mounting shafts521of the guide member52are inserted into the two mounting holes551of the first shutter55, respectively. With this, the guide member52rotatably holds the first shutter55. The first shutter55is rotatably connected to the first upper document tray21via the guide member52.

The first shutter55is provided with mounting holes552in lower portions of both end portions in the longitudinal direction (width direction WD), respectively. The second shutter56is provided with mounting shafts561on upper portions of both end portions in the longitudinal direction (width direction WD), respectively. The two mounting shafts561of the second shutter56are inserted into the mounting holes552of the first shutter55, respectively. With this, the first shutter55rotatably holds the second shutter56. The second shutter56is provided with mounting shafts (protrusions)562on the lower portions (ends on the side of the lower document tray23) of both end portions in the longitudinal direction (width direction WD), respectively. The two mounting shafts562of the second shutter56are inserted into groove holes232ain the two guide portions232of the lower document tray23, respectively. With this, the two mounting shafts562on the lower end portion of the second shutter56are held movably in the feeding direction CD by the groove holes232ain the guide portions232.

FIG.19A,FIG.19B,FIG.19C,FIG.19D, andFIG.19Eare explanatory views of the rotation of the first upper document tray21with respect to the lower document tray23in the second embodiment.FIG.19Ais a perspective view as seen from the left oblique rear side when the first upper document tray21is in the lowered position DP without upward rotation.FIG.19Bis a perspective view as seen from the left oblique rear side when the first upper document tray21is in the raised position UP with upward rotation.FIG.19Cis a perspective view as seen from the right oblique front side when the first upper document tray21is in the raised position UP with upward rotation. As shown inFIG.19A, when the first upper document tray21is in the lowered position DP without upward rotation in the stacking direction SD, the first shutter55and the second shutter56are stored between the first upper document tray21and the lower document tray23. As shown inFIG.19B, when the first upper document tray21is rotated from the lowered position DP to the raised position UP, the second shutter56is rotated and raised in such a manner that the lower end portion of the second shutter56is moved along the groove holes232aof the guide portions232. As the second shutter56is raised, the first shutter55is also raised. When the first upper document tray21is in the raised position UP, the first shutter55and the second shutter56are exposed between the first upper document tray21and the lower document tray23. At this time, the first shutter55and the second shutter56cover the air gap G (gap) created between the first upper document tray21and the lower document tray23on the upstream side in the feeding direction CD within the range RA. That is, the air gap G (gap) is created when the first upper document tray21, the telescopic tray25, the front side regulation guide24, and the rear side regulation guide26are in the raised position UP and the front side regulation guide24and the telescopic tray25are in the retracted position RP. The first shutter55and the second shutter56cover the air gap G (gap) created between the first upper document tray21and the lower document tray23on the downstream side of the telescopic tray25in the feeding direction CD. In addition, the wall portion234provided in the lower document tray23covers the air gap0(gap) created between the first upper document tray21and the lower document tray23on the front side in the width direction WD.

FIG.19Dis a cross-sectional view taken along line XIXD-XIXD inFIG.19B.FIG.19Eis a cross-sectional view taken along line XIXE-XIXE inFIG.19B. As shown inFIG.19D, when the first upper document tray21is in the raised position UP, an inclined portion (first abutment portion)553provided on the first shutter55contacts (abuts) an inclined portion (second abutment portion)522provided on the guide member52. An abutment portion (third abutment portion)554provided on the first shutter55contacts (abuts) an abutment portion (fourth abutment portion)563provided on the second shutter56. At this time, an angle θ formed by the second shutter56and the lower document tray23on the downstream side in the feeding direction CD of the document is an acute angle. An angle α formed by the first shutter55and the second shutter56on the upstream side in the feeding direction CD of the document is an obtuse angle. Therefore, when the first upper document tray21is rotated downward in the direction away from the feeding roller4, the mounting shafts562of the second shutter56can move in the groove holes232aof the guide portions232without resistance, and the first shutter55and the second shutter56are folded. When the first upper document tray21is in the raised position UP as shown inFIG.19E, the mounting shafts562are in contact with the inclined surfaces2321of the groove holes232a. Therefore, even if the first shutter55and the second shutter56receive a force (external force) from the upstream side in the feeding direction CD, the first shutter55and the second shutter56do not rotate.

The feeding of large-size documents by the automatic document feeder1in the second embodiment is the same as in the first embodiment shown inFIG.16AandFIG.16B, so the explanation thereof is omitted.FIG.20AandFIG.20Bare perspective views of the automatic document feeder1in the second embodiment when small-size documents are fed.FIG.20Ais a perspective view of the automatic document feeder1in the second embodiment when a large number of small-size documents are fed.FIG.20Bis a perspective view of the automatic document feeder1in the second embodiment when a small number of small-size documents are fed. When the small-size documents are fed, the front side regulation guide24, the telescopic tray25, and the telescopic tray cover28are integrally retracted to the retracted position RP on the rear side in the width direction WD as shown inFIG.20AandFIG.20B. In the retracted position RP, the telescopic tray25is retracted below the first upper document tray21to expose a portion of the upper surface of the discharge tray3. This improves the visibility of the small-size documents discharged on the discharge tray3. When the large number of small-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are positioned in the lowered position DP as shown inFIG.20A. In the lowered position DP, the small-size documents are separated from the feeding roller4. When the small number of small-size documents are fed, the first upper document tray21, the front side regulation guide24, the telescopic tray25, and the rear side regulation guide26are integrally raised in the stacking direction SD and positioned in the raised position UP as shown inFIG.20Bto enable the small-size documents to be fed. In the raised position UP, the small-size document abuts against the feeding roller4. The wall portion286of the telescopic tray cover28covers the air gap V (FIG.13B) created between the telescopic tray25and the telescopic tray cover28. The first shutter55and the second shutter56are raised to cover the air gap G (FIG.19C) created between the first upper document tray21and the lower document tray23. With this, the first shutter55and the second shutter56prevent foreign matter from entering from the air gap G and also prevent a user from getting the user's finger caught between the first upper document tray21and the lower document tray23from the air gap G.

According to the second embodiment, the first shutter55and the second shutter56are provided to cover the air gap G that is created between the first upper document tray21and the lower document tray23when the first upper document tray is moved to the raised position UP in a state in which the telescopic tray25is retracted below the first upper document tray21. Therefore, foreign matter can be prevented from entering the inside of the document stacking device12from the air gap G that is created between the first upper document tray21and the lower document tray23. According to the second embodiment, foreign matter can be prevented from entering the document tray2.

In the first embodiment and the second embodiment, the upper document tray has the first upper document tray21and the second upper document tray22. However, the upper document tray may be a single tray, and the single tray may be held rotatably relative to the lower document tray23.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2022-077459, filed May 10, 2022, which is hereby incorporated by reference herein in its entirety.