JP4818974B2 - Paper feeding cassette and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding cassette and an image forming apparatus including the same, and in particular, stacks fixed-size sheet materials used in an image forming apparatus such as a printer, a facsimile machine, and a printing machine, and sequentially feeds them during image formation. The present invention relates to a sheet feeding cassette for feeding and an image forming apparatus including the same.

Conventionally, as shown in FIG. 14, a paper feed cassette used in an image forming apparatus such as a copying machine, a printer, or a facsimile is a cassette main body 101, a bottom plate 103 that is rotatable up and down around a fulcrum portion 102, End fence 104 slidable in the feeding direction (direction of arrow A) of sheet material S and fixed at an arbitrary position, sheet material S stored in cassette body 101 (sheet material S placed on bottom plate 103) The sheet material front end restricting portion 105 and the like that align the front end S1 in the feeding direction. The bottom plate 103 is urged by a leaf spring or other pressing member 109 so that the front end S1 side of the accommodated sheet material S is rotated upward. The end fence 104 is slidable in a direction along the feeding direction of the stored sheet material S.
When the sheet material S is stored in the cassette main body 101, as shown in FIG. 14A, the sheet material front end regulating portion S1 of the sheet material S to be stored is brought into contact with the sheet material leading end regulating portion 105, and thereafter Then, the end fence 104 is slid and brought into contact with the rear end S2 in the feeding direction of the sheet material S stored therein, and the sheet material leading end regulating portion 105 and the end fence 104 are moved in the direction along the feeding direction of the sheet material S. The storage position is positioned. When the sheet material S thus positioned is fed and the sheet material S stored in the cassette body 101 decreases, the bottom plate 103 moves the fulcrum 102 by the pressing member 109 as the sheet material S decreases. It pivots upward as the center. With this rotation, the sheet material S stored in the cassette body 101 (sheet material S placed on the bottom plate 103) is lifted on the leading end S1 side in the feeding direction, and the uppermost sheet material S is The state of contacting the outer peripheral surface of the paper feed roller 106 is maintained.

However, as the bottom plate 103 is rotated upward, the distance d1 between the sheet material S placed on the bottom plate 103 in the feeding direction and the sheet material front end restricting portion 105 gradually increases, and eventually FIG. As shown in (b), the contact between the sheet feeding roller 106 and the uppermost sheet material S becomes poor, and a feeding error occurs.
Therefore, in order to prevent the occurrence of such a feeding mistake, as shown in FIG. 15, the rear end S2 in the feeding direction of the sheet material S stored in the cassette body 101 is moved forward (the leading end of the sheet material). The use of an end fence 108 provided with pressing means 107 for pressing toward the regulating portion 105 side) has been proposed and put into practical use (for example, see Patent Document 1). The pressing means 107 is provided so as to be rotatable in the direction along the feeding direction A of the sheet material S around the fulcrum portion 109, and forwardly in the feeding direction by an urging body (not shown) such as a spring. It is always urged toward a certain sheet material front end restricting portion 105 side. When the pressing means 107 is not in contact with the sheet material S or when the stored sheet material S is reduced, the pressing means 107 is used as shown in FIGS. 15 (a) and 15 (c). Protrudes forward in the feed direction.

When the sheet material S is stored in the cassette body 101 provided with the end fence 108, as shown in FIG. 15 (b), the leading end portion S1 in the feeding direction of the stored sheet material S is used as the sheet material leading end regulating portion. 105, and then the end fence 108 is slid forward in the feeding direction to bring the pressing means 107 into contact with the rear end S2 of the sheet material S in the feeding direction, and the end fence 108 is fixed at that position. is doing. At this time, by pressing the pressing means 107 strongly against the rear end S2 in the feeding direction of the sheet material S, the pressing means 107 is resisted against the urging force of the urging means as shown in FIG. It is rotated to a retracted position (a position that does not protrude forward in the feeding direction).
When the sheet material S stored in this way is fed and the sheet material S in the cassette body 101 decreases, the bottom plate 103 becomes a fulcrum as the sheet material S decreases as shown in FIG. The sheet material S is rotated upward about the sheet 102, and the sheet material S stored in the cassette body 101 is lifted at the leading end S1 in the feeding direction. Further, the pressing means 107 urged by the urging means is brought into contact with the rear end S2 in the feeding direction of the sheet material S, and the urging force from the pressing means 107 causes the sheet material S to be fed in the feeding direction. Pushed forward. For this reason, even when the sheet material S on the bottom plate 103 decreases and the bottom plate 103 rotates upward about the fulcrum portion 102, the distance between the leading end portion of the sheet material S in the feeding direction and the sheet material leading end regulating portion 105. Is maintained constant, the contact state between the sheet feeding roller 106 and the uppermost sheet material S is maintained constant, and stable feeding is performed.
JP 2005-263497 A

However, in the case described in Patent Document 1, even when the end fence 108 having the pressing means 107 as shown in FIG. 15 is used, the operation of storing the sheet material S in the cassette body 101 is unfamiliar or inconvenient. Due to attention or the like, the fixed position of the end fence 108 may be an inappropriate position. Specifically, when the end fence 108 is slid forward in the feeding direction of the sheet material S to bring the pressing means 107 into contact with the rear end portion in the feeding direction of the sheet material S, FIG. As described above, the sliding operation is stopped at the position where the pressing means 107 rotating forward in the feeding direction of the sheet material S by the urging force of the urging means contacts the rear end S2 in the feeding direction of the sheet material S. In this case, the end fence 108 is fixed at that position. In such a case, when the sheet material S on the bottom plate 103 decreases and the bottom plate 103 rotates upward, the pressing means 107 that has already rotated to the protruding position supplies the sheet material S on the bottom plate 103. The sheet cannot be pushed forward (sheet material front end restricting portion 105 side). Thus, as in the case shown in FIG. 14B, as shown in FIG. 16B, the sheet material S placed on the bottom plate is fed as the bottom plate 103 rotates upward. The distance d2 between the direction front end portion S1 and the sheet material front end restricting portion 105 gradually increases, and eventually the contact between the feeding roller 105 and the uppermost sheet material S becomes poor as shown in FIG. Misfeeds will occur.
The present invention has been made in consideration of the above circumstances, and provides a sheet feeding cassette capable of appropriately pressing by detecting the pressing state of the rear end of the sheet material by the pressing means, and an image forming apparatus including the same. The purpose is to provide.

In order to solve the above-mentioned problems, the invention according to claim 1 includes a cassette body that stores a sheet material, and the sheet material that is urged upwardly and attached to the cassette body so as to be vertically rotatable. A bottom plate to be placed, an end fence main body attached to the cassette main body so as to be movable in a direction along the feeding direction of the sheet material placed on the bottom plate, and feeding the sheet material to the end fence main body A paper feed cassette comprising: a fixing means portion for fixing to a cassette body at an arbitrary position in the direction; and an end fence having a pressing means for pressing the rear end of the sheet material placed on the bottom plate forward in the feeding direction. The end fence comprises a detecting means for detecting that the rear end of the sheet material placed on the bottom plate is pressing the surface of the pressing means.
According to a second aspect of the present invention, in the paper feeding cassette according to the first aspect, the detecting means detects a pressure applied by the sheet material by a load change caused by a sheet material rear end on the surface of the pressing means. .
According to a third aspect of the present invention, in the paper feed cassette according to the first aspect, the detection means is an optical sensor attached to the pressing means, and is irradiated toward the rear end of the sheet material from the optical sensor. The pressing by the sheet material is detected by the change in the amount of reflected light.

According to a fourth aspect of the present invention, in the paper feeding cassette according to the first aspect, the detection means includes a detection portion that is slidably mounted from the surface of the pressing means, and the detection means includes the pressing portion. It is characterized in that it is provided so as to be able to protrude and sunk from the surface of the means, and is provided with a detecting portion, and the detecting portion is pressed by the rear end of the sheet material so as to be flush with the surface of the pressing means.
According to a fifth aspect of the present invention, in the paper feed cassette according to any one of the first to fourth aspects, when the end fence is not detected by the detecting means by the sheet material, Extruding means for extruding the rear end forward in the feeding direction is provided.
According to a sixth aspect of the present invention, in the paper feed cassette according to the fifth aspect, the pushing means is an pushing means for pushing the pressing means from the rear of the pressing means.
According to a seventh aspect of the present invention, in the paper feed cassette according to any one of the first to sixth aspects, the case body includes display means for displaying a pressed state with the sheet material detected by the detection means. It is characterized by having.
According to an eighth aspect of the present invention, in the paper feed cassette according to the seventh aspect, the display means is formed on an end fence.
The invention according to claim 9 is the sheet feeding cassette according to claim 7 or 8, wherein the display means is a display means for emitting a warning sound when the detection means does not detect pressing by the sheet material. Features.

According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising: a sheet feeding cassette that stores a sheet material; and an image forming unit that forms an image on the sheet material fed from the sheet feeding cassette. Is a paper feed cassette according to any one of claims 1 to 9.
The invention according to claim 11 is the image forming apparatus according to claim 10, wherein the image forming apparatus includes a display unit that displays a pressing state of the sheet material detected by the detecting unit. To do.
According to a twelfth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, the display unit is a display unit that emits a warning sound when the detection unit does not detect pressing by the sheet material. To do.
According to a thirteenth aspect of the present invention, in the image forming apparatus according to any one of the tenth to twelfth aspects, the image forming apparatus includes an image forming unit that forms an image on a sheet material, and detects the paper feed cassette. When the means does not detect pressing by the sheet material, a control unit is provided that stops image output of the image forming unit.
According to a fourteenth aspect of the present invention, in the image forming apparatus according to the thirteenth aspect, the control unit detects the pressing by the sheet material while the sheet material is being conveyed to the image output unit. If not, control is performed so that image output of the image forming unit is stopped after an image is formed on the sheet material being conveyed.

  According to the present invention, by adopting the above configuration, a sheet feeding cassette capable of detecting a pressing state of the rear end of the sheet material by the pressing unit and enabling appropriate pressing, and an image forming apparatus including the sheet feeding cassette are provided. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a printer as an image forming apparatus according to an embodiment of the present invention. In the main body case 1 of the printer of the present embodiment, a sheet feeding cassette 2 that can be freely inserted and removed, and a sheet material S such as a transfer sheet stored in the sheet feeding cassette 2 are separated and fed one by one. Formed on a certain feeding roller 3, an image forming unit 4 for forming an image on the sheet material S to be separated and fed, a registration roller 5 for timing of feeding the sheet material S to the image forming unit 4, and the sheet material S A fixing unit 6 for fixing the image (toner image) is provided.
The image forming unit 4 supplies a drum-shaped photosensitive member 8 on which an electrostatic latent image is written by exposure from the optical writing unit 7, a charger 9 for uniformly charging the surface of the photosensitive member before exposure, and toner. A developing device 10 that visualizes the electrostatic latent image on the photoconductor 8 as a toner image, a transfer device 11 that transfers the toner image to the sheet material S, and a cleaning device 12 that collects residual toner on the photoconductor after the transfer is completed. Etc. On the upper surface of the main body case 1, a paper discharge unit 13 for discharging the sheet material S on which the toner image is fixed in the fixing unit 6 is formed. A manual feed tray 14 on which the sheet material S can be manually fed is provided on the side surface of the main body case 1 so as to be freely opened and closed.

When an image is formed on the sheet material S by this printer, in the image forming unit 4, a photosensitive member in which exposure by a laser beam or the like corresponding to image information from the light writing unit 7 is uniformly charged in advance by the charger 9. 8 is irradiated to form an electrostatic latent image of the image. As the photoconductor 8 rotates, toner is supplied from a developing device 10 attached around the photoconductor 8, and the toner adheres electrostatically to the electrostatic latent image to form a toner image. On the other hand, the sheet material S fed one by one by the sheet feeding roller 3 from the sheet feeding cassette 2 at the bottom of the case body 1 is conveyed to the registration roller 5 and is pressed against the photoconductor 8 by the registration roller 5 at a transfer timing. The transfer device 11 is fed. In the transfer device 11, a predetermined voltage is applied to transfer the toner image carried on the photoreceptor 8 onto the surface of the sheet material S. In this way, the toner image transferred onto the sheet material S is fed to the fixing unit 6, and the toner image is heated and pressurized to be fixed on the sheet material S and discharged from the paper discharge unit 13. .
The image forming apparatus according to the present invention is not limited to the monochrome image forming apparatus shown in the above embodiment, but includes a color image forming apparatus and an ink jet image forming apparatus using liquid ink.

Next, since the present invention is characterized by the structure of the paper feed cassette, the paper feed cassette will be described based on an embodiment.
[Example 1]
FIG. 2 is a diagram illustrating a schematic configuration of the paper feed cassette 2 according to the first embodiment of the present invention. FIG. 2A is a diagram in which the sheet material S is stored in a full state in the paper feed cassette 2, and FIG. It is a figure which shows the case where the accommodated sheet material S is a small amount. The sheet feeding cassette 2 is a box-shaped cassette body 15 that is open at the top and can store the sheet material S, and a bottom plate that is disposed in the cassette body 15 and is pivotable up and down around the fulcrum portion 16. 17. Sheet material S leading edge regulating portion 18 that aligns the feeding direction leading edge S1 of the stored sheet material S, and slidable in the direction along the feeding direction of the sheet material S. An end fence 19 that aligns the rear end S2 in the feeding direction, a friction separation pad 20 that abuts on the outer peripheral surface of the feeding roller 3 and separates and feeds the sheet material S together with the feeding roller 3 and the like.
The bottom plate 17 is rotated by a push-up type or pull-up type spring 22 in a direction in which the leading end S <b> 1 of the sheet material S placed on the bottom plate 17 contacts the outer peripheral surface of the feeding roller 3. Is biased upward. Accordingly, as the sheet material S placed on the bottom plate 17 is conveyed to the image forming unit 4 of the image forming apparatus and the storage amount of the sheet material S is reduced, as shown in FIG. The leading end in the transport direction A is pushed up by the spring 22, and the uppermost sheet material S is pressed against the paper feed roller 3. As the sheet material S pressed against the sheet feeding roller 3 in this way, one sheet of the uppermost sheet material S is fed rightward by the rotation of the sheet feeding roller 3 and is fed to the image forming unit 4 of the image forming apparatus described above. Sent.

As described above, when the front end of the bottom plate 17 is rotated upward, a gap d1 is generated between the front end S1 of the sheet material S and the paper feed roller 3 as described above with reference to FIG. In order to prevent this, as shown in FIG. 2 (b), a pressing plate 23, which is a pressing means, is rotatably attached at a fulcrum 31 to an end fence body 19a that restricts the movement of the rear end S2 of the sheet material. The rear end S2 of the sheet material S is pressed in the feeding direction A by the rear end 23a of the pressing plate 23 by a spring member (not shown) or the like attached to the rear of the plate 23.
As shown in FIG. 3, the end fence 19 has a fixing means portion 21 attached to the rear of the end fence main body 19 a, and an inverted T-shaped fitting protrusion formed at the bottom of the fixing means portion 21. It has a portion 21a. The fitting protrusion 21a engages with a guide groove (not shown) extending in the feeding direction A of the bottom plate 17, and guides the end fence 19 to be movable in the direction along the feeding direction of the sheet material S. At the same time, a stopper (not shown) formed at the bottom of the fixing means 21 and the bottom plate 17 come into contact with each other to prevent and fix the end fence 19 at an arbitrary position. When the end fence 19 is released from being fixed by the stopper portion of the fixing means portion 21, the user grasps the grip portion 19b of the end fence main body 19a with a finger and pulls the grip portions 19b in the B direction to fix the end fence portion 21b. The contact between the stopper portion and the bottom plate 17 is released, and the sheet member S can be freely moved in the feeding direction along the fitting protrusion 21 a and the guide groove of the bottom plate 17. In this embodiment, the guide groove and the stopper contact portion are formed on the bottom plate 17, but may be formed on the bottom portion 15a of the cassette body 15 instead of the bottom plate.

Further, the end fence 19 is configured such that the rear end S <b> 2 of the sheet material S placed on the bottom plate 17 presses the surface of the pressing plate 23 between the fixing means portion 21 and the pressing plate 23. The pressure sensor 24 is provided as a detecting means for detecting the pressure, and the pressure sensor 24 presses against the biasing force of the spring member of the pressing plate 23 of the pressing end 23 of the sheet material S (load force). ) Is detected. Accordingly, as shown in FIG. 4A, when the sheet material S is placed on the bottom plate 17 in a full state, a large load force that overcomes the biasing force of the spring member that presses the pressing plate 23 is obtained. When the number of sheet materials S placed on the bottom plate 17 decreases, the load force on the pressing plate 23 by the rear end S2 of the sheet material S decreases. The load force applied to the pressing plate 23 by the rear end S2 of the sheet material S is detected by the pressure sensor 24.
The end fence 19 is improperly fixed, and as shown in FIG. 4B, a gap is generated between the rear end S2 of the sheet material S and the pressing plate 23, and the rear end S2 of the sheet material S is pressed. When the end fence 19 is fixed in a state where it is not pressed by the plate 23, the load force due to the rear end S2 of the sheet material S is detected by the pressure sensor 24 as a pressure substantially equal to zero. As described above, when the end fence 19 is improperly fixed, the gap d2 is generated between the leading end S1 of the sheet material S and the leading end regulating portion 18 as described with reference to FIG. It cannot be transported forward.
In the present invention, in order to cope with such an accident, the load force of the rear end S2 of the sheet material S is measured by the pressure sensor 24 attached to the end fence 19, and the load force does not exceed a predetermined value. Is determined that the rear end S2 of the sheet material S is not properly pressed against the pressing plate 23 and displayed on a display unit (not shown) such as a panel of the image forming apparatus. The image forming process is stopped.

FIG. 5 is a block diagram of an apparatus that controls the operation of the display device and the image forming unit based on detection by the pressure sensor 24 according to the present embodiment. After the sheet material S is compared by comparing the load force applied to the pressing plate 23 by the rear end S2 of the sheet material S detected by the pressure sensor 24 and a preset reference load force stored in the storage unit 31. The determination unit 30 determines whether the pressing of the end S2 against the pressing plate 23 is appropriate. The result is input to the control unit 32, and according to this result, the control unit 32 displays an appropriate or inappropriate situation on the display unit 33. At the same time, if the determination result of the determination unit 30 is inappropriate, the image forming unit drive unit 34 is controlled to stop the image output in the image forming unit 4 of the image forming apparatus.
In this way, the display unit 33 can display an indication that the sheet material S is not properly set, and can take actions such as prompting the user to correct the sheet material S setting state. Since the sheet feeding in an unstable state is not continued, stable sheet feeding can be performed.
Further, when the determination result of the determination unit 30 is inappropriate, the image output in the image forming unit 4 of the image forming apparatus is stopped, so that the sheet material S is not supplied in an unstable state. Since the paper is not continued, it is possible to suppress the occurrence of conveyance troubles such as non-feeding.
Further, in this embodiment, as shown in FIG. 5, a detection unit 35 that detects the presence or absence of the sheet material S is provided in the conveyance path of the sheet material S of the transfer machine 11 from the sheet feeding roller 3 of the image forming apparatus. When an unsuitable determination result is input to the control unit 32 by the determination unit 30, the image output from the image forming unit 4 is not stopped immediately, and the sheet of the transfer machine 11 is transferred from the paper supply roller 3 of the image forming apparatus. When the sheet material S is detected in the conveying path of the material S, the image forming process of the sheet material S existing in the conveying path is performed, and the image formation is performed after the image forming process for the sheet material S is completed. The image output process in the unit 4 is stopped.
By performing such control, the image output is stopped after the conveyance of the sheet material S being conveyed is completed. Therefore, the sheet material does not remain in the conveyance path of the image forming apparatus, and the sheet material S jams. Transport accidents such as can be prevented.

  As described above, the sheet feeding cassette in this embodiment stores the sheet material S in the sheet feeding cassette 2 and moves the end fence 19 forward in the sheet material S feeding direction to feed the sheet material S. When being brought into contact with the rear end S2, the pressing body 23 in a state of protruding forward in the sheet feeding direction by the biasing force of the biasing means such as a spring member comes into contact with the rear end S2 of the sheet material S, By detecting the pressing force of the rear end S2 of the sheet material S by the pressure sensor 24, it is possible to continue to detect whether or not a gap is generated between the end fence 19 and the rear end S2 of the sheet material S. . Thereby, the sheet material S on the bottom plate 17 is reduced by feeding the sheet material S, the bottom plate 17 is rotated upward, and the pressing body 23 biased by the biasing body and the feeding direction of the sheet material S Even when a gap occurs at the rear end S2, the image forming apparatus can recognize the occurrence of the gap as a signal, and therefore, an action such as prompting the user to correct the set state of the sheet material S can be performed. Since the sheet feeding is not continued when the sheet material S is in an unstable state, stable sheet feeding can be performed.

[Example 2]
FIG. 6 is a diagram showing a schematic structure of an end fence according to another embodiment of the present invention. In this embodiment, the pressure sensor described in the first embodiment is used as a detecting means for detecting that the rear end S2 of the sheet material S placed on the bottom plate 17 is pressed against the surface of the pressing plate 23. Instead of 24, a reflection type photo interrupter 25 that detects the rear end S2 of the sheet material S is used. That is, as shown in FIGS. 6 and 7, the pressing plate 23 is formed with two through holes 23a and 23b, and the photo interrupter 25 includes a projection unit 25a for projecting light and a light receiving unit 25b. Have. The light projected from the projection unit 25 a of the photo interrupter 25 is projected onto the surface of the pressing plate 23 through the through hole 23 a of the pressing plate 23. As shown in FIG. 7A, when the projected light is placed on the bottom plate 17 in a full state, the projected light is reflected by the rear end S2 of the sheet material S, and the reflected light is pressed against the pressing plate. It is possible to detect that the rear end S2 of the sheet material S is in contact with the surface of the pressing plate 23 by being received by the light receiving portion 25b of the photo interrupter 25 through the through hole 23b.

On the other hand, when the end fence 19 is disposed at an inappropriate position, the rear end S2 of the sheet material S does not contact the surface of the pressing plate 23 as shown in FIG. When formed, the reflected light of the light projected from the photo interrupter 25 at the rear end S2 of the sheet material S is not detected by the light receiving portion 25b of the photo interrupter 25, and the rear end S2 of the sheet material S is pressed against the pressing plate 23. It can be detected that it is not in contact with the surface. In this case, the photo interrupter 25 is attached to the rear surface of the pressing plate 23 and rotates according to the rotation of the pressing plate 23.
As described above, the photo interrupter 25 is used to detect that the rear end S2 of the sheet material S placed on the bottom plate 19 is pressed against the surface of the pressing plate 23 by detecting the amount of reflected light. Since the detection is performed, the contact between the sheet material S and the end fence 19 can be monitored without applying a load such as friction to the sheet material S.

[Example 3]
FIG. 8 is a diagram showing a schematic configuration of an end fence 19 according to another embodiment of the present invention. In this embodiment, the photo-interrupter 25 used in the above-described second embodiment and the sheet material S are pushed using the detection piece 26 as a detection unit that detects the contact of the rear end S2 of the sheet material S with the pressing plate 23. The presence or absence of the sheet material S in front of the backing plate 23 is detected. The detection piece 26 is formed in a dogleg shape, is attached so as to be rotatable around a fulcrum 23 a formed at the rear of the pressing plate 23, and the bent portion 26 b is formed through a through hole 23 a formed in the pressing plate 23. The tip is mounted so that it can protrude and retract. As shown in FIGS. 9A and 9C, the detected portion 26 c of the detection piece 26 is used when the sheet material S is not placed on the bottom plate 17 (see FIG. 9A) or when the bottom plate 17. When the sheet material S placed on the sheet material S is small and the rear end S2 of the sheet material S is not properly pressed by the pressing plate 23 of the end fence 19 (see FIG. 9C), the detection piece 26 The tip of the bent portion 26b protrudes from the surface of the pressing plate 23. In this state, the detected portion 26c of the detection piece 26 covers the light receiving portion 25b of the photo interrupter 25, and the reflected light at the detected portion 26c. Cannot be detected.
On the other hand, when the end fence 19 is fixed at an appropriate position and the rear end S2 of the sheet material S is inserted into the pressing plate 23 until the bent portion 26b of the detection piece 26 is flush with the surface of the pressing plate 23. The detected portion 26c rotates upward about the fulcrum 26a, is separated from the light receiving portion 25b of the photo interrupter 25, reflects the light from the projection portion 25a of the photo interrupter 25, and reflects the reflected light at the light receiving portion 25b. It can be detected. (See Fig. 9 (b))
As described above, the rear end S2 of the sheet material S is appropriately pressed by the pressing plate 23 due to the protrusion and depression of the front end of the bent portion 26b of the detection piece 26 by the rear end S2 of the sheet material S. It is possible to detect whether or not. By using such a detection means, it is possible to detect the appropriateness and improperness of the fixed position of the end fence 19 by the operation of the physical detection piece 26, so a sheet that hardly reflects light, such as an OHP transparent sheet. This has the advantage that detection is possible even with materials.

[Example 4]
FIG. 10 is a diagram showing a schematic configuration of an end fence 19 according to another embodiment of the present invention. In this embodiment, the presence or absence of the sheet material S in front of the pressing plate 23 is detected by the pressure sensor 23 used in the first embodiment. However, in the first embodiment, the detection result is displayed on the display device of the image forming apparatus. However, in this embodiment, the display device is arranged in the paper feed cassette 2 itself. Specifically, an LCD display 27 is attached to the upper surface of the fixing means 21 of the end fence 19 attached to the paper feed cassette 2, and the rear end of the sheet material S by the pressure sensor 23 as shown in FIG. The load force due to S2 is detected, the suitability of the fixing position of the end fence 19 is determined from this load force, and the result is displayed on the LCD display 27 as the display unit 33.
Accordingly, when the sheet material S is set in the paper feed cassette 2, the suitability of the fixing position of the end fence 19 is displayed on the LCD display 27 of the end fence 19, so that the user can supply the sheet material S. The accuracy of the operation when setting the paper cassette 2 can be immediately transmitted to the user, and the setting position can be surely optimized.
In this case, instead of the LCD display, display means using sound such as sound or generation of warning sound can be used as display means. It is also possible to use both the sound display means and the character display means. When the sheet material S is conveyed from the sheet feeding cassette 2 of the image forming apparatus, the end fence 19 is fixed in a state where the urging force by the pressing plate 23 is insufficient with respect to the sheet material S. When the amount of the sheet material S placed on the sheet 2 is reduced and the sheet material rear end S2 is separated from the pressing plate 23 of the end fence 19, a non-feed jam of the sheet material is likely to occur. . For this reason, the sheet material S is urged to be corrected so that a warning state is displayed with an alarm sound or the like, and the sheet material S is corrected to an appropriate position so as not to continue feeding in an unstable state. Therefore, stable paper feeding can be performed.
Further, when the sheet material S is set in the sheet feeding cassette 2, if the fixing position of the end fence 19 is optimum, a sound is transmitted to that effect, and the user is informed that the fixing position is optimum. The set position can be optimized.

[Example 5]
FIG. 11 is a diagram showing a schematic configuration of an end fence 19 according to another embodiment of the present invention. In this embodiment, in addition to the detection of the presence or absence of the sheet material S in front of the pressing plate 23 by the pressure sensor 23 in the above-described first embodiment, according to the detection result, the rear end S2 of the sheet material S is detected. In order to increase the load force when it is determined that the load force is insufficient, an extrusion means 28 for pushing the pressing plate 23 from the rear is attached to the end fence 19.
As shown in FIG. 11, pushing means 28 made of an actuator such as a solenoid is attached behind the pressing plate 23, and as shown in FIG. 12 (a), the sheet material S is full on the bottom plate 17. When the pressure sensor 23 determines that the position is appropriate, the push-out means 28 does not operate. However, when the amount of the sheet material S becomes small, a gap is formed between the rear end S2 of the sheet material S and the pressing plate 23 as shown in FIG. When the fixing position of the end fence 19 is determined to be inappropriate, the pushing means 28 is operated to rotate the pressing plate 23 in the C direction, and the pressing plate 23 sets the rear end S2 of the sheet material S appropriately. It presses so that it may become a sufficient load force.

  FIG. 13 is a block diagram showing a control device for controlling the pushing operation of the pushing means 28. This control device is basically the same as the control device shown in FIG. Is controlled by the pushing means driving unit 36 controlled by the control unit 32 so as to perform the above-described operation. By performing such control, when it is detected that the end fence 19 and the sheet material S are not in contact with each other, the end fence 19 again pushes the rear end S2 of the sheet material S by the pushing means 28 provided on the end fence 19. In order to energize, stable paper feeding is performed.

1 is a schematic diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the paper feed cassette shown in Example 1 by this invention, (a) is sectional drawing which shows the state with which the sheet material was loaded on the bottom plate in a full state, (b) is a small amount of sheet material. It is sectional drawing which shows the state mounted on the baseplate. It is a perspective view which shows the end fence used with the paper feed cassette of Example 1 by this invention. It is a figure which shows the operation state of the end fence shown in FIG. 3, (a) is sectional drawing which shows the state with which the sheet | seat material was filled and was mounted on the baseplate, (b) is a sheet | seat material mounted on a small amount of bottomplates It is sectional drawing which shows the state made. 2 is a block diagram of a display device used in the paper feed cassette according to the first exemplary embodiment of the present invention and a device that controls the operation of the image forming unit. It is a perspective view which shows the end fence used with the paper feed cassette of Example 2 by this invention. It is a figure which shows the operation state of the end fence shown in FIG. 6, (a) is sectional drawing which shows the state with which the sheet | seat material was filled and was mounted on the baseplate, (b) is a sheet | seat material mounted on a small amount of baseplates It is sectional drawing which shows the state made. It is a perspective view which shows the end fence used with the paper feed cassette of Example 3 by this invention. It is a figure which shows the operation state of the end fence shown in FIG. 8, (a) is sectional drawing which shows the state in which the pressing plate is accommodated and the sheet | seat material from which the detection piece protruded is not mounted on the bottom plate, (b) Sectional drawing which shows the state in which the sheet material was mounted on the small amount bottom board, (c) is sectional drawing which shows the state in which the sheet material is mounted on the small amount bottom plate and the sheet material is not detected by the detection piece. It is a perspective view which shows the end fence used with the paper feed cassette of Example 4 by this invention. It is a perspective view which shows the end fence used with the paper feed cassette of Example 5 by this invention. It is a figure which shows the operation state of the end fence shown in FIG. 11, (a) is sectional drawing which shows the state with which the sheet | seat material was filled and was mounted on the baseplate, (b) is a sheet | seat material mounted on a small amount of bottomplates It is sectional drawing which shows the state made. It is a block diagram of the apparatus which controls the action | operation of the extrusion means used with the paper feed cassette of Example 5 by this invention. It is a figure which shows schematic structure of the conventional paper feed cassette, (a) is sectional drawing which shows the state with which the sheet | seat material was filled and was mounted on the baseplate, (b) is a sheet | seat material mounted on a small amount of baseplates. It is sectional drawing which shows the state. It is a figure which shows schematic structure of the conventional paper feed cassette, (a) is sectional drawing which shows the state in which the sheet | seat material is not mounted in the bottom plate, (b) is the sheet | seat material loaded on the bottom plate in the full state. Sectional drawing which shows a state, (c) is sectional drawing which shows the state in which a small amount of sheet | seat materials were mounted on the baseplate. FIG. 16 is a diagram illustrating a schematic configuration of the sheet feeding cassette illustrated in FIG. 15, where (a) is a cross-sectional view illustrating a state where the sheet material is full and is placed on the bottom plate, and (b) is a sheet material placed on the bottom plate in a small amount. It is sectional drawing which shows the state set | placed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body case, 2 Paper feed cassette, 3 Paper feed roller, 4 Image formation part, 5 Registration roller, 6 Fixing part, 7 Optical writing part, 8 Photoconductor, 9 Charger, 10 Developer, 11 Transfer device, 12 Cleaning Part, 15 cassette body, 16 fulcrum part, 17 bottom plate, 18 tip regulating part, 19 end fence, 21 fixing means part, 23 pressing plate, 24 pressure sensor, 25 reflection type photo interrupter, 26 detection piece, 27 LCD display 28 Extruding means

Claims (13)

A cassette main body for storing the sheet material, a bottom plate on which the sheet material attached to the cassette main body so as to be pivoted upward and downward is urged upward, and a sheet material placed on the bottom plate. An end fence body attached to the cassette body so as to be movable in a direction along the feeding direction, and a fixing means for fixing the end fence body to the cassette body at an arbitrary position in the sheet material feeding direction; In a paper feed cassette provided with an end fence having a pressing means for pressing the rear end of the sheet material placed on the bottom plate forward in the feeding direction,
Said end fence, a detection means for the trailing edge of the sheet material surface is placed on the bottom plate of the pressing means detects that the pressing, when the pressing by the sheet material is not detected by said detecting means A sheet feeding cassette comprising: pushing means for pushing the rear end of the sheet material forward in the feeding direction . The paper feed cassette according to claim 1.
The sheet feeding cassette according to claim 1, wherein the detecting unit detects pressing by the sheet material based on a load change caused by a rear end of the sheet material on the surface of the pressing unit. The paper feed cassette according to claim 1.
The detection means is an optical sensor attached to the pressing means, and detects the pressing by the sheet material by a change in the amount of reflected light emitted from the optical sensor toward the rear end of the sheet material. A paper cassette. The paper feed cassette according to claim 1.
The detection means is mounted so as to protrude freely from the surface of the pressing means and includes a detection portion, and the detection portion is pressed by the rear end of the sheet material so as to be flush with the surface of the pressing means. And a pressing by the sheet material is detected. The paper feed cassette according to any one of claims 1 to 4,
The sheet feeding cassette according to claim 1, wherein the pushing means is pushing means for pushing the pushing means from behind the pushing means . The paper feed cassette according to any one of claims 1 to 5,
The paper feed cassette according to claim 1, wherein the case body includes display means for displaying a pressing state with the sheet material detected by the detection means . The paper feed cassette according to claim 6,
The sheet feeding cassette , wherein the display means is formed on an end fence . The paper feed cassette according to claim 6 or 7,
The sheet feeding cassette according to claim 1, wherein the display unit is a display unit that emits a warning sound when the detection unit does not detect pressing by the sheet material . In an image forming apparatus comprising a paper feed cassette for storing a sheet material, and an image forming section for forming an image on the sheet material fed from the paper feed cassette,
The image forming apparatus according to claim 1, wherein the paper feed cassette is the paper feed cassette according to claim 1 . The image forming apparatus according to claim 9.
The image forming apparatus includes a display unit that displays a pressing state of the sheet material detected by the detecting unit. The image forming apparatus according to claim 10.
The image forming apparatus according to claim 1, wherein the display unit is a display unit that emits a warning sound when the detection unit does not detect pressing by the sheet material . The image forming apparatus according to any one of claims 9 to 11,
The image forming apparatus includes an image forming unit that forms an image on a sheet material, and includes a control unit that stops image output of the image forming unit when the detection unit of the sheet feeding cassette does not detect pressing by the sheet material. the image forming apparatus characterized by being. The image forming apparatus according to claim 12.
When the sheet material is conveyed to the image output unit and the detection unit of the sheet feeding cassette does not detect the pressing by the sheet material, the control unit is configured to form the image forming unit after the image is formed on the sheet material being conveyed. The image forming apparatus is controlled so as to stop image output .

Images