Sheet storing apparatus, sheet feeding apparatus, and image forming apparatus

A sheet regulating portion includes a body portion including a regulating surface facing an edge of a sheet, a pressing member having a pressing portion capable of projecting out of the body portion, an upper portion formed integrally with an upper part of the pressing portion so as to project to a sheet side and regulating an upward move of the sheet, and an urging member to urge the pressing member so that the pressing portion presses the edge of the sheet. In addition, a holding portion holds the pressing portion movably from a projecting position where the pressing portion projects out of the body portion to a retracting position where the upper portion enters within the body portion while inclining the pressing portion with respect to the regulating surface by resisting against the urging member when the upper portion is pressed from above.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a sheet storing apparatus, a sheet feeding apparatus, and an image forming apparatus.

Description of the Related Art

An image forming apparatus such as a copier, a printer, and a facsimile machine of a sort of feeding a sheet to an image forming unit from a sheet feeding apparatus to form an image on the sheet is being widely used today. In general, the sheet feeding apparatus includes a sheet feed cassette, i.e., a sheet storing apparatus, removably attached to an apparatus body and feeding the sheet stored in the sheet feed cassette to the image forming unit by a sheet feed roller.

Some of the sheet feed cassettes used in the sheet feeding apparatus includes a sheet supporting plate liftably provided to stack a sheet and to press the sheet against a sheet feed roller for example. The sheet feed cassette is provided with a rear end regulating portion configured to regulate a position of a rear end in a sheet feed direction of the sheet (referred to as a ‘rear end’ hereinafter) stored in the sheet feed cassette which is configured to be able to store different size sheets. The sheet feed cassette is also provided with a pair of side regulating members configured to regulate side end positions in a direction orthogonal to the sheet feed direction (referred to as a ‘width direction’ hereinafter) of the sheet stored in the sheet feed cassette.

Such sheet feed cassette is configured to regulate the rear end of the sheet by the rear end regulating portion while regulating the side ends of the sheet by the pair of side regulating members to regulate a front end position of the sheet always at a predetermined position. This arrangement makes it possible to feed the sheet from a same position and to feed the sheet stably when the sheet feed cassette is stored in an apparatus body.

In the conventional sheet feed cassette, there is a case when the sheet stacked on the sheet supporting plate floats above an upper end of the side regulating portion when the sheet supporting plate rises. The sheet is conveyed askew if the sheet is fed in this condition. Then, in order to regulate the sheet from floating up as described above, a tab-shaped member is provided at an upper end of a unit body regulating a side end of a sheet to press the sheet from above and to regulate the sheet from getting over the upper end of the unit body as disclosed in Japanese Patent Application Laid-open No. 2011-57450.

As another arrangement, a curl presser portion is turnably attached to a front end of a regulating surface of a regulating member configured to regulate a side end of a sheet to regulate a curled part of the sheet from getting over the upper end of the regulating member by the curl presser portion as disclosed in Japanese Patent Laid-open No. 2001-88970 for example. The curl presser portion presses the curled part at an end of the stacked sheet by being held at a position approximately at a right angle with respect to the regulating surface by an urging member.

By the way, in the case of the arrangement of pressing the sheet by the tab-shaped member, it is necessary to store the sheet while avoiding the tab-shaped member so as not to damage the sheet in storing the sheet because the tab-shaped member is fixed to the unit body. Thus, storability of the sheet deteriorates.

Meanwhile, in the case of the arrangement of pressing the sheet by the curl presser portion, the storability of the sheet does not deteriorate in storing the sheet because the curl presser portion turns downward by resisting against an urging force of the urging member by being pressed from above by the stored sheet. However, this arrangement requires a plurality of components, thus leading to an increase of cost and to deterioration of assemblability.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a sheet feeding apparatus includes a sheet feed portion configured to feed a sheet and a sheet storing apparatus configured to store the sheet to be fed by the sheet feed portion and including a side regulating portion configured to regulate a position of the sheet by abutting with a side end of the sheet stored in the sheet storing apparatus. The side regulating portion includes a body portion including an inner wall surface facing the sheet, a pressing portion capable of projecting out of the body portion and of pressing the side end of the sheet, a regulating portion formed integrally with an upper part of the pressing portion so as to project to a sheet side and regulating an upward move of the sheet stored in the sheet storing apparatus, an urging portion configured to urge the pressing portion such that the pressing portion projects out of the body portion so that the pressing portion presses the side end of the sheet, and a holding portion configured to hold the pressing portion movably from a project position where the pressing portion projects out of the body portion to a retract position where the regulating portion enters within the body portion by resisting against the urging member when the regulating portion is pressed from above.

According to a second aspect of the invention, a sheet storing apparatus includes a body configured to store a sheet, and a side regulating portion configured to abut against a side end of the stored sheet to regulate a position of the sheet. The side regulating portion includes a body portion including a regulating surface facing the side end of the sheet to regulate the side end of the sheet, a pressing member comprising a pressing portion projectable/retractable from the body portion and capable of pressing the side end of the sheet, and a regulating portion formed integrally with an upper part of the pressing portion so as to project to a widthwise inner side and regulating an upward move of the sheet stored in the sheet storing apparatus, an urging member configured to urge the pressing member such that the pressing member projects out of the body portion so that the pressing portion presses the side end of the sheet, and a holding portion configured to hold the pressing member movably from a project position where the pressing member projects out of the body portion to a retract position where the regulating portion enters within the body portion by resisting against the urging member when the regulating portion is pressed from above.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will be described in detail below with reference to the drawings.FIG. 1is a schematic diagram illustrating a configuration of an image forming apparatus including a sheet feeding apparatus of a first embodiment. As illustrated inFIG. 1, the image forming apparatus200includes an image forming unit200B provided in an upper part of a body200A of the image forming apparatus200and configured to electro-photographically form an image on a sheet. The image forming apparatus200also includes a sheet feeding apparatus200C provided in a lower part of the image forming apparatus body200A and configured to feed the sheet to the image forming unit200B.

The image forming unit200B is provided with a photosensitive drum212, a laser scanner232, and others. The sheet feeding apparatus200C is provided with a sheet feed cassette300serving as a sheet storing apparatus storing the sheet S and a pickup roller202serving as a sheet feed portion feeding the sheet stored in the sheet feed cassette300.

In response to a feed signal outputted from a controller not illustrated to the sheet feeding apparatus200C in the image forming apparatus200constructed as described above, the sheet S is fed by the pickup roller202from the sheet feed cassette300. After that, the sheet S fed as described above is separated one by one by a feed roller203and a retard roller204and is conveyed to a pre-registration roller pair209and a registration roller pair210through upper drawing roller pairs205and206and upper conveyance roller pairs207and208. While there is a case when the sheet S is conveyed askew by being affected by a conveyance load, variation of precision of components or the like in the process being conveyed to the pre-registration roller pair209, the skew is removed by a holding force and a registration shutter mechanism not illustrated of the registration roller pair210. After that, a top sensor211detects the sheet S whose skew has been corrected.

Meanwhile, based on a signal from the top sensor211, the controller irradiates the photosensitive drum212with a laser beam corresponding to an image signal from the laser scanner232. At this time, by being irradiated with the laser beam, the photosensitive drum212which has been electrified in advance forms an electrostatic latent image thereon. Then, a toner image is formed on the photosensitive drum212by developing the electrostatic latent image by toner.

The toner image is transferred onto a predetermined position on the sheet S when the sheet S is conveyed to a transfer nip portion composed of a transfer roller213and the photosensitive drum212by conducting the exposure and scanning by utilizing the signal of the top sensor211. Then, the toner image is transferred onto the sheet S by the transfer roller213. Thus, a transferred image is formed on the sheet S.

Next, the sheet S onto which the toner image has been transferred is conveyed to a fixing unit200D including a fixing roller215and a pressure roller216. By undergoing heat and pressure applied in the fixing unit200D, the toner melts and the transferred image is fixed on the sheet S. Here, when the sheet S is conveyed to the fixing unit200D and is conveyed by both fixing and transfer nip portions, it is necessary to avoid the image being transferred from being affected by differences of conveying velocities of the photosensitive drum212, the transfer roller213, the fixing roller215and the pressure roller216. To that end, the controller gives the sheet S with an adequate amount of sag between the transfer and fixing rollers by controlling the velocity of the pressure roller216by utilizing a signal of a loop sensor214to control so that the amount is kept always at the adequate amount during when the sheet is conveyed between the transfer roller213and the fixing roller215.

After that, the fixed sheet S is conveyed by a conveyance roller218and is lead to a face down (FD) sheet discharge passage P1by being switched by a switching member219in a case of a simplex printing mode. Then, the sheet S is discharged out of the image forming apparatus body200A through an intermediate sheet discharge roller pair220and a face down (FD) sheet discharge roller pair222and is stacked on a face down (FD) sheet discharge tray224. It is noted that the image forming apparatus200of the present embodiment has a duplex printing mode of forming images on both surfaces of the sheet.

In the case of the duplex printing mode, the sheet S which has passed through the fixing unit200D is lead to a branch passage P2by being switched by the switching member219at first. Then, the sheet S is conveyed by a conveyance roller225to a reversing roller227and to a duplex printing passage P3by reverse rotation of the reversing roller227and switching made by a switching member not illustrated. After that, the sheet S is conveyed to the pre-registration roller pair209again by conveyance rollers229,230, and231provided along the duplex printing passage P3to transfer and fix a toner image again onto another side of the sheet S. Then, the sheet S is discharged by the intermediate sheet discharge roller pair220and the FD discharge roller pair222.

As illustrated inFIG. 2, the sheet feed cassette300configured to store a plurality of sheets includes a cassette body310having a cassette cover311and a sheet supporting plate309serving as a sheet stacking portion stacking the sheets and being movable in a vertical direction. The sheet feed cassette300also includes a rear end regulating member304serving as a rear end regulating portion regulating a rear end position which is an upstream end in the sheet feed direction of the sheet stacked on the sheet supporting plate. The sheet feed cassette300also includes first and second side regulating plates303and305regulating both end positions in the width direction orthogonal to the sheet feed direction of the sheet stacked on the sheet supporting plate. The second side regulating plates303and305serves as a side regulating portions (regulating unit).

The sheet supporting plate309is provided in the cassette body310turnably in the vertical direction centering on a turning center309aand is provided with a separation sheet308pasted at a front end part on a downstream end side in the sheet feed direction of an upper surface thereof. The sheet supporting plate309is provided with a push-up plate314for pushing up the sheet supporting plate309under the sheet supporting plate309.

It is noted that the image forming apparatus body200A is provided with a lift mechanism not illustrated for turning the sheet supporting plate309upward by driving the push-up plate314. Then, in response to a timing when a user inserts the sheet feed cassette300into the image forming apparatus body200A after storing sheets in the sheet feed cassette300, a drive of the lift mechanism is transmitted to the push-up plate314so that the push-up plate314turns upward and the sheet supporting plate309turns upward by being pressed by the push-up plate314. Thereby, the sheet on the sheet supporting plate is pressed against the pickup roller202described and illustrated inFIG. 1disposed approximately above the separation sheet308. When the pickup roller202turns in this condition, the sheet is conveyed in a direction of an arrow inFIG. 2.

The rear end regulating member304moves in the sheet feed direction along a guide portion316provided along the sheet feed direction on a bottom surface of the cassette body310. The rear end regulating member304also includes a rear end regulation manipulating lever313that can be engaged/disengaged to the guide portion316. The engagement with the guide portion316is released by pinching the rear end regulation manipulating lever313. After that, the rear end regulating member304moves by moving the rear end regulation manipulating lever313along the sheet feed direction while pinching the rear end regulation manipulating lever313.

The first and second side regulating plates303and305are provided with body portions303aand305ahaving inner wall surfaces respectively facing widthwise end portions of the sheet. It is noted that the inner wall surface may be also called as a regulating surface for regulating the side end of the sheet. The first and second side regulating plates303and305are attached with racks307aand307bextending respectively in the width direction. The racks307aand307bare meshed with a pinion gear not illustrated and located at a widthwise center part on the bottom surface of the cassette body310.

The first side regulating plate303also includes a side regulation manipulating lever312disengageably engaging with a lock portion not illustrated provided along the width direction on the bottom surface of the cassette body310. The engagement with the lock portion not illustrated is released by pinching the side regulation manipulating lever312. After that, the first and second side regulating plates303and305move in the width direction symmetrically centering on the pinion gear by moving the side regulation manipulating lever312along the width direction while pinching the side regulation manipulating lever312.

Sheets of various sizes can be stored in the sheet feed cassette300by movably providing the rear end regulating member304and the first and second side regulating plates303and305. The sheet can be positioned in setting the sheet by moving the rear end regulating member304and the first and second side regulating plates303and305to the position corresponding to a sheet size.

Here, as illustrated inFIG. 3, a height regulating portion306is provided at an upper end of the second side regulating plate305so as to project toward a sheet side from the body portion305a. The height regulating portion306is provided to prevent a downstream end of the sheet from running on the second side regulating plate305when the sheet is fed. That is, the height regulating portion306makes it possible to prevent the sheet from skewing by preventing the sheet from riding on the second side regulating plate305.

The first side regulating plate303is provided with a pressing member301projectably/retractably from the body portion303a. The pressing member301is configured to be held projectably/retractably by a holder member302which is a holding portion provided in the first side regulating plate303and to be urged projectably from the body portion303aby a urging member315provided between the holder member302and the pressing member301. By being pressed by the pressing member301urged thus by the urging member315, the sheet is pressed against the body portion305aof the second side regulating plate305.

Even if a gap is generated between the sheet stored in the cassette and the first and second side regulating plates303and305, it is possible to press the sheet against the second side regulating plate305by thus pressing the sheet against the body portion305aof the second side regulating plate305. That is, according to the present embodiment, the sheet is pressed against the second side regulating plate305to regulate the position of the sheet. Then, the sheet stored in the cassette can be fed from a fixed position by making the second side regulating plate305as a standard in feeding the sheet.

As illustrated inFIG. 4, the pressing member301includes a pressing body portion3011having an abutment surface3011aabutting with the sheet and serving as a pressing portion capable of pressing the side end of the sheet. The pressing member301includes a height regulating portion301aserving as a regulating portion formed at an upper part of the pressing body portion3011or integrally with an upper end of the abutment surface3011a, and an abutment portion301bprovided at a lower end of the pressing body portion3011. The pressing member301includes bosses301cwhich serve as supported portions and are shafts projectively provided on both widthwise wall surfaces of the pressing body portion3011. The height regulating portion301aregulates an upward move of the sheet to prevent the downstream end of the sheet from running on the first side regulating plate303and is provided so as to project to the sheet side by a predetermined amount from the abutment surface3011aas described above. It is noted that the bosses301care located under and widthwise outside of the height regulating portion301a, and the urging member315is configured so as to urge the pressing member301to widthwise inside under the bosses301cof the pressing member301.

Long holes302awhich are support portions extending respectively in a horizontal direction are defined through opposing widthwise inner wall surfaces of the holder member302. Then, the pressing member301is held by the holder member302movably along the long holes302aand turnably centering on the bosses301cby slidably supporting the bosses301cof the pressing member301by the long holes302a.

Still further, the holder member302is provided with first and second stoppers302cand302das illustrated inFIGS. 5A through 5Ddescribed later. When the pressing member301is urged by the urging member315, the first stopper302cabuts against the abutment portion301bof the pressing member301to regulate a project position of the pressing member301with respect to the second side regulating plate305. When the pressing member301turns at a fulcrum of the bosses301cby resisting against the urging member315, the second stopper302dabuts against the abutment portion301bof the pressing member301to regulate the turn of the pressing member301.

Next, an operation of the pressing member301will be described with reference toFIGS. 5A through 5D.FIG. 5Aillustrates a condition before a sheet is stored in the sheet feed cassette300. At this time, by being urged by the urging member315, the boss301cof the pressing member301abuts against a downstream end, in a direction in which the pressing member301projects, of the long hole302aand the abutment portion301babuts against the first stopper302c.

The user stores the sheet in the sheet feed cassette300in this condition. It is noted that the user stores the sheet by operating the side regulation manipulating lever312and the rear end regulation manipulating lever313in advance corresponding to size of the sheet to move and fix the first and second side regulating plates303and305and the rear end regulating member304at a position corresponding to the size of the sheet. The user stores the sheet from above after that.

Here, the height regulating portion301ais provided so as to project by the predetermined amount from the upper end of the abutment surface3011aas described above. Due to that, when the sheet is stored from above, the sheet abuts against the height regulating portion301aand the height regulating portion301ais pressed by a force F from above by the sheet. Due to the force F, the pressing member301located at the project position projecting from the body portion303aturns centering on the boss301cas illustrated inFIG. 5B. Then, due to a component of the force F generated thus by the turn, the boss301cmoves along the long hole302ato the retract position where the pressing member301and the height regulating portion301aenter within a holder member302(inside of the body portion).

It is noted that when the height regulating portion301aenters completely within the holder member302, the first side regulating plate303is in flush with the body portion303a. Still further, the abutment portion301babuts against the second stopper302dof the holder member302at this time, so that the pressing member301stops.

Thus, it is possible to prevent the height regulating portion301afrom deteriorating the storability of the sheet in storing the sheet by arranging such that the pressing member301moves in a direction in which the height regulating portion301aretracts while turning by being pressed by the sheet and such that the height regulating portion301aenters within the holder member302. That is, it is possible to prevent the storability of the sheet from deteriorating by configuring the pressing member301so as to be turnable and movable from the project position to the retract position.

FIG. 5Cillustrates a condition when the storage of the sheet is completed. At this time, no force is applied from above to the pressing member301by the sheet, so that only urging force of the urging member315acts on the pressing member301. The pressing member301capable of pressing the side end in the width direction of the sheet by the urging force of the urging member315presses the side end in the width direction of the sheet with a constant force. As a result, the sheet may be caused to abut against the second side regulating plate305, and thereby the sheet can be stored at a position corresponding to the size of the sheet.

FIG. 5Dillustrates a condition in which the sheet supporting plate309rises and the sheet is pressed against the pickup roller after attaching the sheet feed cassette300in which the sheet has been stored to the image forming apparatus body200A. Here, if the height regulating portion301ais in contact with an uppermost sheet S1when the sheet is pressed against the pickup roller, the pickup roller becomes resistance in feeding the sheet. Due to that, a certain gap is kept between the uppermost sheet S1and the height regulating portion301awhen the sheet is pressed against the pickup roller. Then, when a drive is transmitted from the image forming apparatus body200A to the pickup roller in this condition, the sheet is fed out of the sheet feed cassette300without receiving any resistance from the height regulating portion301a.

As described above, according to the present embodiment, the height regulating portion301ais integrally formed with the pressing member301and the pressing member301is provided turnably with respect to the first side regulating plate303and movably to the project and retract positions. Thereby, when the sheet abuts with the height regulating portion301awhen the sheet is stored in the sheet feed cassette300and the height regulating portion301ais pressed from above by the sheet, the pressing member301turns and moves to the retract position. Then, because the pressing member301thus turns and moves to the retract position, it is possible to store the sheet while setting the first and second side regulating plates303and305at a position corresponding to size of the sheet. Thus, this arrangement makes it possible to prevent the storability of the sheet from being deteriorated also in such a case.

Still further, because the height regulating portion301amoves to the position in flush with the body portion303aof the first side regulating plate303in maximum in storing the sheet, it is possible to prevent an edge of the sheet from being damaged by the height regulating portion301ain storing the sheet. Still further, the pressing member301is configured such that the pressing member301retracts while turning by receiving the force from the sheet. In other words, the holder member302holds the pressing body portion3011movably from the project position to the retract position while inclining with respect to the regulating surface. This arrangement makes it possible to move the pressing member301to the retract position even if the force applied to the pressing member301is small.

This arrangement makes it possible to move the pressing member301to the retract position even if the position where the sheet is set varies and the force applied to the pressing member301becomes small. As a result, it becomes unnecessary to provide a tapered height regulating portion by considering the variation of the position where the sheet is set. Accordingly, it is possible to prevent the height regulating portion from being enlarged in width and height directions and along with that, to downsize the first side regulating plate303and the sheet feed cassette300.

Next, a second embodiment of the present disclosure will be described.FIG. 6is an enlarged perspective view of a main part of a first side regulating plate provided in the sheet feed cassette of the sheet feeding apparatus of the present embodiment. It is noted that inFIG. 6, the same reference numerals with those described inFIG. 4denote the same or corresponding components.

According to the present embodiment, the long holes302aof the holder member302are inclined obliquely downward such that a downstream side thereof in the retract direction is lowered as illustrated inFIG. 6. In other words, according to the present embodiment, the long holes302aare inclined such that a height position of the pressing member301is lowered when the pressing member301moves to the retract position.

Thereby, when the height regulating portion301aillustrated inFIG. 7Areceives a force F from a sheet, the pressing member301turns centering on the boss301cand moves obliquely downward along the long holes302aby a component of the force F as illustrated inFIG. 7B. Then, the pressing member301enters within the holder member and moves to the retract position where the height regulating portion301ais flush with the body portion303aof the first side regulating plate303.

After that, when the storage of the sheet is completed, no force is applied to the pressing member301from above by the sheet. Then, the pressing member301moves obliquely upward by the urging force of the urging member315and presses the side end in the width direction of the sheet with a constant force as illustrated inFIG. 7C. As a result, the sheet is caused to abut against the second side regulating plate305and thereby, the sheet can be stored at the position corresponding to the size of the sheet.

After that, the sheet supporting plate309rises and the sheet is pressed against the pickup roller after attaching the sheet feed cassette300in which the sheet has been stored to the image forming apparatus body200A. At this time, as illustrated inFIG. 7D, a certain gap is kept between the uppermost sheet S1and the height regulating portion301aso that the height regulating portion301adoes not become feeding resistance in feeding the sheet by the pickup roller. Then, when a drive is transmitted from the image forming apparatus body200A to the pickup roller in this condition, the sheet is fed out of the sheet feed cassette300without receiving any resistance from the height regulating portion301a.

As described above, according to the present embodiment, the long holes302aare defined aslant such that the downstream side in the retract direction is lowered. This arrangement makes it possible to efficiently transmit the pressing force of the sheet to the pressing member301and to move the pressing member301in the retract direction more smoothly when the pressing member301is pressed by the sheet to be stored. Still further, because the pressing member301is configured so as to move in the oblique direction, it is possible to shorten a length in the width direction of the first side regulating plate303and to downsize the first side regulating plate303and the sheet feed cassette300.

Next, a third embodiment of the present disclosure will be described.FIG. 8is an enlarged perspective view of a main part of a first side regulating plate provided in the sheet feed cassette of the sheet feeding apparatus of the present embodiment. It is noted that inFIG. 8, the same reference numerals with those described inFIG. 4denote the same or corresponding components.

As illustrated inFIG. 8, the holder member302is provided with opening portions302bdefined through inner wall surfaces facing widthwise with each other and serving as support portions by which the bosses301cof the pressing member301are movably supported. Each of the opening portions302bincludes a bottom surface302b1inclined obliquely downward. Thereby, the pressing member301is held turnably by the opening portions302band movably obliquely downward and upward along the bottom surface302b1.

Next, an operation of the pressing member301will be described with reference toFIGS. 9A through 9D.FIG. 9Aillustrates a condition before a sheet is stored in the sheet feed cassette300. At this time, by being urged by the urging member315, the boss301cof the pressing member301abuts against a downstream end in the projection direction of the opening portion302band the abutment portion301babuts against the first stopper302c.

If the height regulating portion301areceives a force F from the sheet stored in this condition, the pressing member301moves obliquely downward along the bottom surface302b1by a component of the force F while turning centering on the boss301cas illustrated inFIG. 9B. Here, when the pressing member301moves thus obliquely downward, the pressing member301moves without being regulated in the vertical direction because there is a space x where the boss301cis movable upward between a top surface302b2and the bottom surface302b1of the top surface302b2.

FIG. 9Cillustrates a condition when the storage of the sheet is completed. At this time, no force is applied from above to the height regulating portion301aby the sheet, so the pressing member301moves obliquely upward by the urging member315as illustrated inFIG. 9Cand presses the side end in the width direction of the sheet with a constant force. As a result, the sheet is caused to abut against the second side regulating plate305and can be stored at a position corresponding to the size of the sheet.

FIG. 9Dillustrates a condition in which the sheet supporting plate309rises and the sheet is pressed against the pickup roller after attaching the sheet feed cassette300in which the sheet has been stored to the image forming apparatus body200A. Here, a certain gap is kept between the uppermost sheet S1and the height regulating portion301ain order to prevent the height regulating portion301afrom becoming resistance in conveying the sheet by the pickup roller. Then, when a drive is transmitted from the image forming apparatus body200A to the pickup roller in this condition, the sheet is fed out of the sheet feed cassette300without receiving any resistance from the height regulating portion301a.

Here, an amount of the sheets that can be stored in the sheet feed cassette300will be described. According to the present embodiment, the sheets can be stored up to a position S1illustrated inFIG. 9B. This position S1can be determined whether or not the pressing member301can return to a position indicated inFIG. 9Cwithout pressing the height regulating portion301aby the end of the sheets S even in a case where the pressing member301retracts completely to a position indicated inFIG. 9C.

InFIG. 9B, height of the position of the height regulating portion301athat has turned is approximately equal to height of the position of the uppermost sheet S1, and the pressing member301cannot return to the position indicated inFIG. 9Cin this case. However, according to the present embodiment, because the pressing member301is configured such that the boss301ccan move upward due to the shape of the opening portion302b, the pressing member301can move obliquely upward and can return to the position indicated inFIG. 9Cwhen the pressing member301is urged by the urging member315.

The position of the uppermost sheet S1can be heightened and more sheets can be stored by holding the pressing member301by the opening portion302bdefined as described above in the present embodiment. It is noted that it is necessary to keep a certain gap between the uppermost sheet S1and the height regulating portion301aas described above in the condition ofFIG. 9D. To that end, a sheet liftable amount of the sheet supporting plate309is set to be small as compared to those of the first and second embodiments. This arrangement makes it possible to feed and convey the sheet out of the sheet feed cassette300without changing the position of the uppermost sheet, i.e., a sheet feeding position, after lifting the sheet supporting plate309.

As described above, according to the present embodiment, the more sheets can be stored by supporting the pressing member301by the opening portion302bin which the space x enabling the boss301cto move upward is defined between the bottom surface302b1and the top surface302b2. Still further, in a case when a number of sheets to be stacked in the sheet feed cassette300is determined to be 500 sheets for example, the configuration of the present embodiment makes it possible to lower the height of the first side regulating plate303and to downsize the sheet feed cassette300in the vertical direction.

Next, a fourth embodiment of the present disclosure will be described.FIG. 10is an enlarged perspective view of a main part of a first side regulating plate provided in the sheet feed cassette of the sheet feeding apparatus of the present embodiment. It is noted that inFIG. 10, the same reference numerals with those described inFIG. 4denote the same or corresponding components.

According to the present embodiment, two (plurality of) bosses301care arrayed in the vertical direction through both side wall surfaces in the width direction of the pressing member301. Still further, two (plurality of) long holes302ainclined such that the downstream side in the retract direction is lowered are defined in the vertical direction and in parallel through inner wall surfaces opposing in the width direction of the holder member302. Then, the pressing member301is held by the holder member302movably while keeping the same attitude along the long holes302aby slidably attaching the bosses301cof the pressing member301respectively to the plurality of long holes302a.

Thereby, as illustrated inFIG. 11A, when the height regulating portion301areceives a force F from the sheet, the pressing member301moves obliquely downward while keeping the same attitude along the two long holes302aby a component of the force F as illustrated inFIG. 11B. Then, the pressing member301moves until when the height regulating portion301aenters within the holder member and becomes flush with the body portion303aof the first side regulating plate303.

When the storage of the sheets is completed after that, no force is applied to the pressing member301from above by the sheets. Due to that, the pressing member301obliquely upward by the urging member315and presses the side end in the width direction of the sheet with a constant force as illustrated inFIG. 11C. As a result, the sheets are caused to abut against the second side regulating plate305and can be stored at the position corresponding to the size of the sheet.

After that, the sheet supporting plate309rises and the sheets are pressed against the pickup roller after attaching the sheet feed cassette300in which the sheet has been stored to the image forming apparatus body200A. At this time, as illustrated inFIG. 11D, a certain gap is kept between the uppermost sheet S1and the height regulating portion301aso that the height regulating portion301adoes not become the feeding resistance in feeding the sheet by the pickup roller. Then, when a drive is transmitted from the image forming apparatus body200A to the pickup roller in this condition, the sheet is fed out of the sheet feed cassette300without receiving any resistance from the height regulating portion301a.

As described above, because the two long holes302aare defined in parallel and obliquely in the present embodiment, the pressing force of the sheet can be efficiently transmitted to the pressing member301in pressing the pressing member301from above by the sheets to be stored. This arrangement makes it possible to move the pressing member301smoothly in the retract direction. It is also possible to shorten the widthwise length of the first side regulating plate303and to downsize the sheet feed cassette300by causing the pressing member301to retract in the oblique direction. It is noted that although the long holes302aobliquely defined are used as the support portion supporting the bosses301cof the pressing member301in the present embodiment, the opening portion302bof the third embodiment described above may be also used as the support portion.

Still further, although the configuration which enables the first and second side regulating plates303and305to move by operating the side regulation manipulating lever312has been described in the above descriptions, the present disclosure is not limited to such configuration. The present disclosure is also applicable to a configuration in which the first and second side regulating plates303and305are fixed like a sheet feed cassette300which corresponds only to a sheet whose widthwise size is constant. Still further, although the present disclosure has been applied to the first side regulating plate303, it is possible to prevent the deterioration of the storability of the sheet even if the present disclosure is applied to the rear end regulating member304.

Still further, while the pressing member301has been provided with the shaft and the holder member302has been provided with the support portion in the above description, the support portion may be provided in the pressing member301and the shaft may be provided in the holder member302. That is, the boss301cmay be provided in one of the pressing member301and the holder member302, and the long hole302aor the opening portion302bmay be provided in the other one of the pressing member301and the holder member302.

This application claims the benefit of Japanese Patent Application No. 2016-014409, filed Jan. 28, 2016, which is hereby incorporated by reference herein in its entirety.