SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS

BACKGROUND OF THE INVENTION
Field of the Invention

The present invention relates to a sheet feeding apparatus configured to feed a sheet and to an image forming apparatus including the same.

Description of the Related Art

Hitherto, a printer including a sheet feeding unit configured to feed a sheet loaded in a manual sheet feed portion has been proposed by Japanese Patent Application Laid-open No. 2016-216155 for example. The manual feed tray includes a cover openably and closably supported by an apparatus body of the printer, a base tray and an auxiliary tray supported on an upper surface of the cover and an interlock mechanism configured to move the base tray in an interlock manner with an opening and closing operations of the cover. The auxiliary tray moves from a storage position to a lifting position along with the opening operation of the cover.

According to Japanese Patent Application Laid-open No. 2016-216155, the auxiliary tray is configured to move from the storage position to the lifting position by being brought into pressure contact with a hook portion of the base tray.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a sheet feeding apparatus includes an apparatus body, a cover openably and closably supported between a first closed position and a first open position with respect to the apparatus body, a first supporting portion movable between a second closed position where the first supporting portion is accommodated in the apparatus body and a second open position where the first supporting portion is capable of supporting a sheet, an interlocking portion configured to move the first supporting portion from the second closed position to the second open position in a case where the cover is opened from the first closed position to the first open position, a second supporting portion drawably supported by the first supporting portion and capable of supporting the sheet together with the first supporting portion, and a feed portion configured to feed the sheet supported by the first and second supporting portions. A moving angle of the first supporting portion in moving from the second closed position to the second open position is smaller than a moving angle of the cover in moving from the first closed position to the first open position.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an overall configuration of a printer according to a present exemplary embodiment.

FIG. 2 is a perspective view illustrating a manual sheet feed portion.

FIG. 3 is a perspective view illustrating a front cover.

FIG. 4A is a perspective view illustrating a link arm seen from one direction.

FIG. 4B is a perspective view illustrating the link arm seen from another direction.

FIG. 5A is a perspective view illustrating a manual feed tray seen from an upper surface side.

FIG. 5B is a perspective view illustrating the manual feed tray seen from a bottom surface side.

FIG. 6 is a perspective view illustrating an extension tray.

FIG. 7 is a section view illustrating the manual sheet feed portion in a case where the front cover is positioned at a closed position.

FIG. 8 is a section view illustrating the manual sheet feed portion in a case where the front cover is located at an open position.

FIG. 9 is a section view illustrating a state in which the extension tray is drawn out of the manual feed tray.

FIG. 10 is a section view illustrating a state in which the front cover is closed while the extension tray is drawn out.

DESCRIPTION OF THE EMBODIMENTS
Overall Configuration

A printer 1 serving as an image forming apparatus of the present exemplary embodiment is an electro-photographic type full-color laser beam printer. As illustrated in FIG. 1, the printer 1 includes an image forming unit 100 configured to form an image on a sheet S, a cassette sheet feed portion 300, a fixing portion 400 and a manual sheet feed portion 500. The image forming unit 100 includes four process cartridges 110Y, 110M, 110C and 110K respectively configured to form four color toner images of yellow (Y), magenta (M), cyan (C) and black (K) and a scanner unit 120.

Note that the four process cartridges 110Y, 110M, 110C and 110K have the same configuration except of that colors of images to be formed are different. Therefore, the configuration and an image forming process of only the process cartridge 110Y will be described below and descriptions of the process cartridges 110M, 110C and 110K will be omitted.

The process cartridge 110Y includes a photosensitive drum 111, a charging roller 113 and a developing roller 114. The photosensitive drum 111 is constructed by applying an organic photoconductive layer on a circumference of an aluminum cylinder and is rotated by a driving motor not illustrated. Note that a photoconductive belt may be used instead of the photosensitive drum 111. The image forming unit 100 includes an intermediate transfer belt 201 wound around a driving roller 105, a tension roller 121 and others. The intermediate transfer belt 201 is rotated by the driving roller 105 clockwise in FIG. 1. Provided inside of the intermediate transfer belt 201 are primary transfer rollers 115Y, 115M, 115C and 115K.

The fixing portion 400 includes a fixing film 401 heated by a heater not illustrated and a pressure roller 402 in pressure contact with the fixing film 401. The cassette sheet feed portion 300 is provided at a lower part of the printer 1 and includes a sheet feed cassette 301 drawable from and attachable to a printer body 1A serving as an apparatus body.

Next, an image forming operation of the printer 1 thus constructed will be described. As an image signal is inputted to the scanner unit 120 from a personal computer or the like not illustrated, the scanner unit 120 irradiates the photosensitive drum 11 of the process cartridge 110Y with a laser beam corresponding to the image signal.

At this time, a surface of the photosensitive drum 111 has been homogeneously charged with a predetermined polarity and potential by the charging roller 113 in advance and an electrostatic latent image is formed on the surface of the photosensitive drum 1111 by the laser beam irradiated from the scanner unit 120. The electrostatic latent image formed on the photosensitive drum 111 is developed by the developing roller 114 to be a toner image of yellow (Y) on the photosensitive drum 111.

In the same manner, the respective photosensitive drums of the process cartridges 111M, 111C and 111K are also irradiated by the scanner unit 120 with the laser beams, and toner images of magenta (M), cyan (C) and black (K) are formed on the photosensitive drums, respectively. The respective toner images formed on the respective photosensitive drums are then transferred by primary transfer rollers 115Y, 115M, 115C and 115K onto the intermediate transfer belt 201 and are conveyed to a secondary transfer roller 203 by the intermediate transfer belt 201 rotated by the driving roller 105.

Note that the image forming processes of the respective colors are performed with a timing of superimposing on an upstream toner image primarily transferred onto the intermediate transfer belt 201. Toner left on the surface of the photosensitive drum 111 after transferring each color toner image onto the intermediate transfer belt 201 is removed by a cleaning unit not illustrated.

In parallel with the image forming process, a sheet S accommodated in the sheet feed cassette 301 of the cassette sheet feed portion 300 or a sheet supplied from a manual sheet feed portion 500 is fed by a pickup roller 311. The sheet S fed by the pickup roller 311 serving as a feed portion is separated one by one at a separation nip formed by a feed roller 312 and a separation roller 313.

A torque limiter not illustrated is attached to the separation roller 313 such that the separation roller 313 does not rotate in a case where two more sheets enter the separation nip and such that the separation roller 313 is rotated by the feed roller 312 in a case where one sheet enters the separation nip. Note that a so-called retard roller system of inputting a rotational drive in a direction opposite to a sheet feeding direction may be adopted instead of the separation roller 313.

The sheet S separated one by one by the separation nip is then conveyed to a registration roller pair 321. The registration roller pair 321 corrects a skew of the sheet S and conveys the sheet S with a predetermined timing synchronized with the image forming process. Then, a full-color toner image on the intermediate transfer belt 201 is transferred onto the sheet S by a secondary transfer bias applied to the secondary transfer roller 203.

The sheet S onto which the toner image has been transferred is then conveyed to the fixing portion 400 to undergo predetermined heat and pressure by the fixing film 401 and the pressure roller 402 of the fixing portion 400 to melt and secure, i.e., to fix, the toner onto the sheet S. The sheet S which has passed through the fixing portion 400 is discharged onto a discharge tray 404 by a discharge roller pair 403.

Manual Feed Portion

Next, a configuration of the manual sheet feed portion 500 serving as a sheet feeding apparatus will be described with reference to FIGS. 1 through 6. As illustrated in FIGS. 1 and 2, the manual sheet feed portion 500 includes a front cover 350, a manual feed tray 351, an extension tray 352, link arms 353L and 353R, a sheet feed unit 354 and others. Parts configured to support at least the link arms 353L and 353R and parts configured to support the front cover 350 of the printer body 1A are also included in the manual sheet feed portion 500 in the present exemplary embodiment.

The front cover 350 serving as a cover of the manual sheet feed portion 500 is openably and closably supported to the printer body 1A centering on an opening and closing shaft 355 between a closed position, i.e., a first closed position as illustrated in FIG. 7 and an open position, i.e., a first open position as illustrated in FIG. 8. The front cover 350 is positioned at the closed position when no sheet is fed in the manual sheet feed portion 500 and composes a part of an exterior face of the printer 1 at this time. The front cover 350 is positioned at the open position when a sheet is to be fed in the manual sheet feed portion 500.

A user loads a sheet on a manual feed tray 351 attached to the front cover 350 while positioning the front cover 350 at the open position. In a case where a sheet to be fed by the manual sheet feed portion 5X) is a long-size sheet for example, an extension tray 352 described later may be drawn out of the manual feed tray 351 to support the long-size sheet by the manual feed tray 351 and the extension tray 352.

The sheet feed unit 354 includes a pickup arm 354a pivotably supported by the printer body 1A centering on a feed roller shaft 357a. The sheet feed unit 354 also includes a pickup roller 356 rotatably supported by the pickup arm 354a and a feed roller 357. As a job of feeding a sheet from the manual sheet feed portion 500 is inputted in a state in which the sheet is stacked in the manual feed tray 351 of the manual sheet feed portion 5X), the pickup arm 354a pivots such that the pickup roller 356 is lowered.

Then, the sheet is fed as the pickup roller 356 rotates in a state in which the pickup roller 356 is in contact with the sheet on the manual feed tray 351. The sheet fed by the pickup roller 356 is conveyed toward the registration roller pair 321 by the feed roller 357 and conveyance roller pairs 359, 360 and 361.

As illustrated in FIG. 3, the front cover 350 includes an inner surface 350f facing to the printer body 1A at the closed position and ribs 350c, 350g and 350h provided along outer edge of the inner surface 350f and extending in a direction of separating from the exterior face 350m. These ribs 350c, 350g and 350h are provided so as to rise up from the inner surface 350f to improve stiffness of the front cover 350.

Provided also inside of the ribs 350c, 350g and 350h of the front cover 350 is a pair of tray supporting portions 350kL and 350kR formed so as to rise up from the inner surface 350f. A first guide rail 350aL, a second guide rail 350bL and a restriction rib 350dL are formed on the tray supporting portion 350kL. A first guide rail 350aR, a second guide rail 350bR and a restriction rib 350dR are formed on the trav supporting portion 350kR. The first guide rails 350aL and 350aR are disposed respectively downstream of the second guide rails 350bL and 350bR in terms of the sheet feeding direction FD. The restriction ribs 350dL and 350dR are formed so as to extend inside in the width direction W at upper end portions of the tray supporting portions 350kL and 350kR.

Next, while the link arms 353L and 353R will be described below, the link arms 353L and 353R are formed to be symmetrical in the width direction W (see FIG. 2) orthogonal to the sheet feeding direction FD. Therefore, the link arm 353L serving as a pivot member will be mainly described below with reference to FIG. 4 and a description of the link arm 353R will be appropriately omitted.

As illustrated in FIGS. 4A and 4B, the link arm 353L includes a boss 353bL formed at a first end portion and a boss 353cL formed at a second end portion. The boss 353cL is supported pivotably by the printer body 1A, and the boss 353bL engages with the second guide rail 350bL of the front cover 350. In the same manner, the link arm 353R includes a boss 353bR formed at a first end portion and a boss 353cR formed at a second end portion (see FIG. 2). The boss 353cR is supported pivotably by the printer body 1A and the boss 353bR engages with the second guide rail 350bR of the front cover 350.

FIG. 5A is a perspective view illustrating the manual feed tray 351 seen from a stacking plane 351a, i.e., an upper surface side, and FIG. 5B is a perspective view illustrating the manual feed tray 351 seen from an opposite surface, i.e., a bottom surface side of the stacking plane 351a. The manual feed tray 351 serving as a first supporting portion is movable between a closed position, i.e., a second closed position illustrated in FIG. 7 and an open position, i.e., a second open position illustrated in FIG. 8. The manual feed trav 351 is accommodated in the printer body 1A when the manual feed tray 351 is positioned at the closed position and is cable of supporting the sheet when the manual feed tray 351 is positioned at the open position.

As illustrated in FIGS. 5A and 5B, the manual feed tray 351 includes a stacking plane 351a formed on the upper surface of the manual feed tray 351 and on which the sheet is stacked and first shafts 351bL and 351bR and second shafts 351cL and 351cR projecting from both side surface of the manual feed tray 351. The second shafts 351cL and 351cR serving as first bosses engage respectively with holes 353aL and 353aR formed through the bosses 353bL and 353bR of the link arms 353L and 353R.

First shafts 351bL and 351bR serving as second bosses of the manual feed tray 351 engage respectively with the first guide rails 350aL and 350aR formed on the tray supporting portions 350kL and 350kR of the front cover 350. The first shafts 351bL and 351bR are held slidably within the first guide rails 350aL and 350aR.

Holding guides 351dL and 351dR are provided at an upstream end portion in the sheet feeding direction FD and at both end portions in the width direction W of the manual feed tray 351. Still further, wall portions 351fL and 351fR are formed at the both end portions in the width direction W of the manual feed tray 351. An inclined portion 351e is formed at the upstream end portion in the sheet feeding direction FD of the manual feed tray 351.

As illustrated in FIG. 6, the extension tray 352 serving as a second supporting portion is provided with a pair of guide ribs 352aL and 352aR at the both widthwise end portions, and a grip portion 352d, that can be gripped by the user, is provided at the upstream end portion in the sheet feeding direction FD. The pair of guide ribs 352aL and 352aR are held slidably by the holding guides 351dL and 351dR of the manual feed tray 351 (see FIGS. 5A and 5B). The more the grip portion 352d extends in the width direction W, the more the grip portion 352d projects upward so as to have a function of holding the sheet stacked in the manual feed tray 351 and the extension tray 352 from not slipping out of the extension trav 352.

A pair of abutment portions 352eL and 352eR and a pair of claw portions 352bL and 352bR are provided at a downstream end portion in the sheet feeding direction FD of the extension tray 352. The pair of claw portions 352bL and 352bR is disposed inside in the width direction W of the pair of abutment portions 352eL and 352eR. The pair of abutment portions 352eL and 352eR abuts with an under surface of the manual feed tray 351 in a state in which the extension tray 352 is drawn out of the manual feed tray 351. That is, the extension tray 352 is supported by the holding guides 351dL and 351dR from underside and abuts with the under surface of the manual feed tray 351 so as to keep a posture of being drawn out of the manual feed tray 351.

Opening Operation of Front Cover

Next, an opening operation of the front cover 350 will be described with reference to FIGS. 7 and 8. Note that because one side in the width direction W of the manual sheet feed portion 500 operates in the same manner with another side, only a left side in the width direction W of the manual sheet feed portion 500, i.e., a side denoted by the reference sign ‘L’, will be described below. FIG. 7 is a section view illustrating a state in which the front cover 350 and the manual feed tray 351 are positioned at the closed position, and FIG. 8 is a section view illustrating a state in which the front cover 350 and the manual feed tray 351 are positioned at the open position.

As illustrated in FIG. 7, the exterior face 350m of the front cover 350 is disposed so as to vertically extend to configure a part of the exterior face of the printer 1 when the front cover 350 is positioned at the closed position. At this time, the manual feed tray 351, the extension tray 352, the link arm 353L and the sheet feed unit 354 are accommodated inside of the printer body 1A and take a posture of erecting approximately in the vertical direction. The manual feed tray 351 and the extension tray 352 are nonvisible from the user by being covered by the ribs 350c. 350g and 350h of the front cover 350.

When the front cover 350 is positioned at the closed position, the second shaft 351cL of the manual feed tray 351 is positioned at a side closer to an upper end portion of the second guide rail 350bL and to the exterior face 350m. In the same manner, the first shaft 351bL of the manual feed tray 351 is positioned at a side closer to an upper end portion of the first guide rail 350aL and to the exterior face 350m. A distance between a center C1 of the second shaft 351cL and the exterior face 350m at this time is defined as a distance D1, and a distance between a center C2 of the first shaft 351bL and the exterior face 350m is defined as a distance D2. Note that the distance D1 is greater than the distance D2, i.e., D1>D2, in the present exemplary embodiment. The second shaft 351cL may be called as a first part of the manual feed tray 351, and the first shaft 351bL may be called as a second part of the manual feed tray 351. The second shaft 351cL is positioned downstream of the first shaft 351bL in terms of the sheet feeding direction FD. The extension tray 352 is drawn out of the manual feed tray 351 in a direction opposite to the sheet feeding direction FD. Therefore, the second shaft 351cL is positioned upstream of the first shaft 351bL in terms of the direction in which the extension tray 352 is drawn out of the manual feed tray 351.

The front cover 350 can be opened and closed centering on an opening and closing shaft 355, and the user can conduct an opening operation on the front cover 350 from the closed position as illustrated in FIG. 7 to the open position as illustrated in FIG. 8. As the opening operation is conducted on the front cover 350 as illustrated in FIGS. 7 and 8, the boss 353bL of the link arm 353L moves within the second guide rail 350bL and abuts with the abutment surface 350nL of the second guide rail 350bL. Thereby, the front cover 350 is held at the open position. Still further, because the second shaft 351cL of the manual feed tray 351 is engaged with a hole 353aL formed through the boss 353bL (see FIG. 4B), the second shaft 351cL moves together with the boss 353bL and is positioned in a vicinity of the abutment surface 350nL.

Similarly to that, as the front cover 350 is opened, the first shaft 351bL of the manual feed tray 351 moves within the first guide rail 350aL and abuts with an abutment surface 350pL of the first guide rail 350aL. These abutment surfaces 350nL and 350pL are positioned at downstream end portions in the sheet feeding direction FD of the second guide rail 350bL and the first guide rail 350aL, respectively.

Thus, the manual feed tray 351 moves from the closed position to the open position in linkage with the move of the front cover 350 from the closed position to the open position. At this time, the manual feed tray 351 moves relatively to the front cover 350. More specifically, along with the opening operation of the front cover 350, the first shaft 351bL and the second shaft 351cL of the manual feed tray 351 move within the first guide rail 350aL and the second guide rail 350bL such that the manual feed tray 351 moves from the closed position to the open position. That is, the link arm 353L and the first guide rail 350aL serving as a hole portion constitute an interlocking portion 600 that moves the manual feed tray 351 from the closed position to the open position when the front cover 350 is opened from the closed position to the open position.

The first guide rail 350aL and the second guide rail 350bL are formed such that the closer to the downstream side in the sheet feeding direction FD, the narrower their widths become. Therefore, the first shaft 351bL and the boss 353bL engage with the first guide rail 350aL and the second guide rail 350bL with almost no rattling in the state in which the front cover 350 is positioned at the open position, so that rattling of the front cover 350 is reduced.

When the front cover 350 is positioned at the open position, a distance between the center C1 of the second shaft 351cL and the exterior face 350m is defined as a distance D3, and a distance between the center C2 of the first shaft 351bL and the exterior face 350m is defined as a distance D4. Note that the distance D3 is larger than the distance D4, i.e., D3>D4.

Then, the distances D1, D2, D3 and D4 are set such that a relationship of D3/D1<D4/D2 holds in the present exemplary embodiment. The distances D1, D2, D3 and D4 are also set such that a relationship of (D3−D1)<(D4−D2) holds in the present exemplary embodiment.

Thereby, as illustrated in FIG. 8, a moving angle θ2 of the manual feed tray 351 in moving from the closed position to the open position is smaller than a moving angle θ1 of the front cover 350 in moving from the closed position to the open position, i.e., θ2<θ1. In FIG. 8, a line along the exterior face 350m of the front cover 350 positioned at the closed position is represented by a broken line F11, and a line along the exterior face 350m of the front cover 350 positioned at the open position is represented by a broken line F12. Aline along an outer side surface of the manual feed tray 351 positioned at the closed position is also represented by a broken line F21, and a line along an outer side surface of the front cover 350 positioned at the open position is represented by a broken line F22. The broken lines F11 and F21 extend approximately in the vertical direction and are in parallel with each other in the present exemplary embodiment. Note that the broken lines F11 and F21 need not be always in parallel with each other. The moving angle θ1 is an angle formed between the broken lines F11 and F12, and the moving angle θ2 is an angle formed between the broken lines F21 and F22.

That is, the manual feed tray 351 takes such a posture that the upstream end portion in the sheet feeding direction FD is lifted up with respect to an inner surface of the front cover 350. In other words, the upstream end portion in the sheet feeding direction FD of the manual feed tray 351 is positioned at a position separated from the exterior face 350m of the front cover 350 more than the downstream end portion in the sheet feeding direction FD of the manual feed tray 351. The extension tray 352 slidably or drawably supported by the manual feed tray 351 also takes such a posture that an upstream end portion in the sheet feeding direction FD is lifted up with respect to the inner surface of the front cover 350. That is, when the manual feed tray 351 moves from the closed position to the open position, the upstream end portion in the sheet feeding direction FD of the manual feed tray 351 is displaced largely with respect to the front cover 350 more than the downstream end portion in the sheet feeding direction FD.

Draw-Out Operation of Extension Tray

Next, a draw-out operation of the extension tray 352 will be described with reference to FIGS. 9 and 10. The user can draw out the extension tray 352 toward upstream in the sheet feeding direction FD by grasp the grip portion 352d of the extension tray 352 in a state in which the front cover 350 is positioned at the open position. At this time, the guide rib 352aL of the extension tray 352 is supported slidably by the holding guide 351dL of the manual feed trav 351.

Then, as the claw portion 352b of the extension tray 352 engages with an end portion of an inclined portion 351e of the manual feed tray 351, the extension tray 352 is held in a state of being drawn out of the manual feed tray 351. The claw portion 352bL is also provided with an inclined plane 352c. The inclined plane 352c protrudes in a sheet thickness direction, i.e., in a direction separating from the extension tray 352, to close a part of a gap formed between the manual feed tray 351 and the extension tray 352. The inclined plane 352c also enables to smoothly deliver a sheet to the inclined portion 351e of the manual feed tray 351.

The user often sets a sheet on the manual feed tray 351 while sliding a leading edge of the sheet along the upper surface of the extension tray 352 in the state in which the extension tray 352 is drawn out of the manual feed tray 351. If there is a level difference between the extension tray 352 and the manual feed tray 351 at this time, there is a possibility that the leading edge of the sheet is caught by the level difference and sheet settability is hampered. However, because the sheet is smoothly guided from the inclined plane 352c of the claw portion 352bL to the inclined portion 351e of the manual feed tray 351 in the present exemplary embodiment, the sheet settability can be improved.

By the way, the front cover 350 is required to have a certain degree of stiffness such that the front cover 350 is not bent when the user operates to open or close the front cover 350. To that end, the front cover 350 includes the rib 350c at the upstream end portion in the sheet feeding direction FD thereof as described above. Still further, downsizing of the printer 1 and the manual sheet feed portion 500 is demanded lately. That is, it is desired to assure stiffness of the front cover 350 while realizing downsizing of the manual sheet feed portion 500 in a state in which the front cover 350 is closed.

For instance, in a case where the rib 350c is provided at the upstream end portion in the sheet feeding direction FD of the front cover 350 as described in the present exemplary embodiment, it is necessary to draw out the extension tray 352 while avoiding the rib 350c. In a case where the draw-out direction of the extension tray 352 is approximately in parallel with the exterior face 350m of the front cover 350, the extension tray 352 has to be disposed at height that exceeds the rib 350c, thus enlarging the manual sheet feed portion 500.

Then, according to the present exemplary embodiment, the manual feed tray 351 is accommodated in a posture of running along the front cover 350 in the state in which the front cover 350 is positioned at the closed position to downsize the manual sheet feed portion 500 as illustrated in FIG. 7. When the extension tray 352 is seen along the draw-out direction of the extension tray 352 in this state, the extension tray 352 overlaps with the rib 350c. Meanwhile, in the state in which the front cover 350 is positioned at the open position as illustrated in FIG. 8, the manual feed tray 351 takes a posture in which the upstream end portion in the sheet feeding direction FD is lifted up with respect to the front cover 350. In this state, the extension tray 352 does not overlap with the rib 350c when the extension tray 352 is seen along the draw-out direction. The manual feed tray 351 takes the position in which the upstream end portion in the sheet feeding direction FD is lifted up from the front cover 350. Then, the holding guide 351dL of the manual feed tray 351 guides the draw-out operation of the extension tray 352 such that the extension tray 352 does not abut with the rib 350c. Therefore, the extension tray 352 can be drawn out of the manual feed tray 351 such that the extension tray 352 passes above the rib 350c without interfering with the rib 350c.

The manual feed tray 351 automatically takes a position as illustrated in FIG. 8 by opening the front cover 350, and the extension tray 352, slidably supported by the manual feed tray 351, follows the manual feed tray 351. Then, because the user performs a drawing-out operation of the extension tray 352, mechanical reliability is high and it is possible to achieve both improvements of stiffness of the front cover 350 and of drawability of the extension tray 352. Still further, because the manual feed tray 351 does not take such a posture that the upstream end portion in the sheet feeding direction FD is lifted up with respect to the front cover 350 in the state in which the front cover 350 is positioned at the closed position, the apparatus can be downsized.

The position of the extension tray 352 is restricted widthwise by the wall portions 351fL and 351fR of the manual feed tray 351 and vertically by the restriction ribs 350dL and 350dR. Therefore, it is possible to reduce rattling during the drawing operation of the extension tray 352 and to improve drawing operability of the extension tray 352.

It is also conceivable that the user operates and closes the front cover 350 in a state in which the extension tray 352 is drawn out by forgetting to accommodate the extension tray 352 into the manual feed tray 351. When the front cover 350 is closed from the open position to the closed position, the upstream end portions in the sheet feeding direction FD of the manual feed tray 351 and the extension tray 352 approach to the inner surface of the front cover 350. However, because the extension tray 352 interferes with the rib 350c of the front cover 350 in the state in which the extension tray 352 is drawn out, there is a possibility that the manual feed tray 351 and the extension tray 352 are damaged if the user tries to forcibly close the front cover 350.

Then, according to the present exemplary embodiment, the first guide rail 350aL of the front cover 350 is formed such that the closer to an outside in a radial direction orthogonal to the pivot direction of the front cover 350, the wider the width of the first guide rail 350aL is as illustrated in FIG. 10. Therefore, the first shaft 351bL is movable by deviating from a moving locus of the first shaft 351bL in opening or closing the front cover 350 in the state in which the extension tray 352 is accommodated in the manual feed tray 351 as illustrated in FIGS. 7 and 8.

If the user tries to close the front cover 350 from the open position to the closed position in the state in which the extension tray 352 is drawn out, the first shaft 351bL of the manual feed tray 351 moves from the position as illustrated in FIG. 8 in a direction of gradually approaching to the front side of the front cover 350 and to the exterior face 350m of the front cover 350. However, the extension tray 352 being drawn out interferes with the rib 350c of the front cover 350 on a way of the closing operation of the front cover 350.

If the user tries to close the front cover 350 further to the closed position at this time, the first shaft 351bL moves to an upper left corner of the first guide rail 350aL as illustrated in FIG. 10. That is, the first shaft 351bL moves within the first guide rail 350aL so as to release a force received by the extension trav 352 from the printer body 1A. Due to that, it is possible to mitigate impact received by the manual feed tray 351 and the extension tray 352 from the printer body 1A and to suppress the manual feed trav 351 and the extension tray 352 from being damaged.

As described above, according to the present exemplary embodiment, the front cover 350 is provided with the ribs 350c, 350g and 350h to improve stiffness of the front cover 350. The rib 350c is positioned at the position farther from the opening and closing shaft 355 serving as an opening and closing center of the front cover 350 than the extension tray 352 being attached to the manual feed tray 351 as illustrated in FIG. 7. Space saving of the manual sheet feed portion 5X) is realized when the front cover 350 is positioned at the closed position and the sheet feeding apparatus can be downsized by the manual feed tray 351, the extension tray 352 and the rib 350c constructed as described above.

Still further, the moving angle θ2 of the manual feed tray 351 in moving from the closed position to the open position is smaller than the moving angle θ1 of the front cover 350 in moving from the closed position to the open position as illustrated in FIG. 8. The upstream end in the sheet feeding direction FD of the manual feed tray 351 is lifted up from the front cover 350 by opening the front cover 350 to the open position by thus setting the opening angles of the manual feed tray 351 and the front cover 350.

This arrangement makes it possible to smoothly draw out the extension tray 352 out of the manual feed tray 351 without interfering with the rib 350c of the front cover 350 and to improve drawing operability of the extension tray 352. Thus, it is possible to improve the drawing operability of the extension tray 352 while increasing the stiffness of the front cover 350 and downsizing the sheet feeding apparatus.

Other Embodiments

It is noted that while the front cover 350 is provided with the ribs 350c, 350g and 350h in the exemplary embodiment described above, the present disclosure is not limited to such configuration. For instance, it is not necessary to provide all of the ribs 350c, 350g and 350h on the front cover 350, and either one or two of the ribs 350c. 350g and 350h may be provided on the front cover 350. Still further, shapes, sizes and dispositions of the ribs provided on the front cover 350 are not limited.

The manual feed tray 351 includes the second shafts 351cL and 351cR supported by the link arms 353L and 353R and the first shafts 351bL and 351bR supported by the first guide rails 350aL and 350aR of the front cover 350 in the exemplary embodiment described above. Then, while the manual feed tray 351 is opened or closed by moving the second shafts 351cL and 351cR and the first shafts 351bL and 351bR in opening or closing the front cover 350, the present disclosure is not limited to such configuration. That is, the configuration of the interlocking mechanism of the front cover 350 and the manual feed tray 351 is not limited such configuration.

Still further, while the electro-photographic printer 1 has been used to describe the exemplary embodiment described above, the present disclosure is not limited such printer. For instance, the present disclosure is also applicable to an inkjet type image forming apparatus configured to form an image on a sheet by discharging ink droplets from a nozzle. The present disclosure may be applied also to a sheet feeding apparatus of an optional sheet feeding deck connected to an image forming apparatus.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention 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. 2020-205494, filed Dec. 11, 2020, which is hereby incorporated by reference herein in its entirety.

SHEET FEEDING APPARATUS AND IMAGE FORMING APPARATUS

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Abstract

Description

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Priority Claims (1)