JPH0657573B2 - Sheet feeding device - Google Patents

Description

The present invention relates to a sheet feeding device provided in an image forming apparatus (hereinafter referred to as a copying machine) such as a copying machine and a laser beam printer.

(B) Conventional Technology Conventionally, a cassette for storing a large number of sheets is known, but the cassette 2'includes an intermediate plate 12 for stacking a large number of sheets S ... As shown in FIG. The middle plate 12
Is mounted on the copying machine when the cassette 2'is installed.
It is configured to be lifted by a lifter inserted from an opening formed from the front surface to the bottom surface to press the large number of sheets S ... Further, restriction plates 13 for restricting the width direction of the sheet S are installed on both sides of the cassette 2 '.

Therefore, when the cassette 2'is inserted from the attachment / detachment port of the copying machine, the lifter is inserted into the cassette 2'from the copying machine side, whereby the intermediate plate 12 is lifted and placed on the intermediate plate 12. The sheets S are pressed against the feeding roller and the like.
In this state, when the copying operation is started, the sheets S, which are in contact with the rollers, are sequentially fed to the copying section by the rotation of the feeding roller.

(C) Problems to be Solved by the Invention However, since the above-described cassette 2'regulates only the width direction of a large number of sheets S stacked on the middle plate 12,
When the cassette 2'is pulled out from the copying machine, a reaction force is exerted on the sheet contacting the feeding roller due to friction with the feeding roller, so that the sheet S located above is the first one. 5 As shown by the chain line in FIG. 2, there is a problem that it pops out in the carrying direction.

(D) Means for Solving the Problem The present invention is intended to solve the above-mentioned problems, and a sheet storage device for storing a sheet to be fed by the sheet feeding means is detachably attached. In the provided sheet feeding device, a lifter means that presses the sheets stacked on the sheet placing portion of the sheet storage device to the sheet feeding means, and releases the pressure contact according to the detachment of the sheet storage device, A sheet regulating member that is disposed on the front side in the sheet feeding direction of the sheets stacked on the placing unit and is movable to a regulation position for regulating the movement of the sheet in the sheet feeding direction and a standby position that does not regulate the sheet, and the sheet. Biasing means for biasing the regulating member to maintain the regulating position, and pressing the sheet regulating member against the biasing force of the biasing means according to the mounting operation of the sheet storage device. The regulatory position Pressing means for moving the sheet storage device to the standby position from the standby position, and when the sheet storage device is detached, the sheet restricting member moves from the standby position to the restricting position by the biasing device to restrict the sheet. To do.

(E) Operation Based on the above configuration, when the sheet storage device is mounted on the sheet feeding device, the pressing means presses the sheet regulating member according to the mounting operation of the sheet storage device, and the sheet regulating member is moved to the regulating position. To the standby position. as a result,
The movement of the sheet in the sheet feeding direction is not restricted, and when the sheet feeding unit is driven, the sheet pressed against the sheet feeding unit is fed into the sheet feeding apparatus. On the other hand, when the sheet storage device is pulled out from the sheet feeding device, the lifter means releases the pressure contact of the sheet with the sheet feeding means.
When the sheet storage device is pulled out in this way, the pressing means and the sheet regulating member are disengaged, and the sheet regulating member is moved from the standby position to the regulating position by the urging means. Therefore, the movement of the sheet in the sheet feeding direction is restricted, and the sheet does not jump out of the sheet storage device regardless of the pulling operation of the sheet storage device.

(F) Example Hereinafter, an example according to the present invention will be described with reference to the drawings.

As shown in FIG. 4, the sheet feeding device 1 includes a cassette (sheet storage device) 2 for storing a large number of sheets S, and a lift device (lifter) for urging the sheets S stored in the cassette 2 upward. Means) 3 and a sheet feeding roller (sheet feeding means) 5 for feeding the sheets S, and a separation pad 6 for separating the sheets S one by one. And
The separation pad 6 is fixed to a lower guide plate 7 biased upward by a spring 7a, and an upper guide plate 9 is arranged in parallel with the lower guide plate 7. Further, a registration roller pair 10 that conveys the sheet in synchronization with an image of an image forming unit (not shown) is disposed downstream of the pair of guide plates 7 and 9.

On the other hand, the cassette 2 is, as shown in FIGS. 1 and 2,
A box-shaped main body 11 is provided, and an intermediate plate (sheet mounting portion) 12 on which the sheets S are stacked is installed in the main body 11 so as to be vertically movable. Further, the cassette 2 is provided with restriction plates 13a and 13b for restricting the width direction of the sheet S,
A portion 11e where the lift device 3 is located is opened from the bottom plate 11h to the front plate 11i. Further, on the one side front side of the cassette 2, an arm plate 15 having a substantially L shape in a plan view is provided.
The arm plate 15 is rotatably supported by a shaft 16 protruding from the side plate 11a of the cassette body 11 and is retained by an E-ring 16a. The arm plate 15 is urged to the bottom of the arm plate 15. A leaf spring (biasing means) 17 is fixed. Further, the side plates 11a and 11b of the cassette body 11 are
Grooves 11c and 11d are provided on the front upper part of the front plate 11a, and front faces 11f and 11g of the side plates 11a and 11b are inclined. Further, an elongated hole 19 is formed on the upstream side of the shaft 16 of the arm plate 15 so that the major axis thereof is the vertical direction.
A pin 20 is projectingly provided on the main body 11 and fitted with a pin 20 to restrict the rotation of the arm plate 15. An arm cam 21 is fixed to the stepped portion of the arm plate 15 by thermal caulking or the like, and the arm plate 15 is configured to rotate when the cam 21 is pressed and released. The arm plate 15 is the sheet regulating member of the present invention.

On the other hand, in the lift device 3, as shown in FIG. 3, a shaft 23 is rotatably installed on shaft support plates 22 and 22 fixed to a not-shown copying machine body, and both ends of the shaft 23 are rotatable. Pressure cams 25, 25 are fixed to the. Also, the shaft 2
A pressure plate 26 is rotatably supported substantially at the center of the pressure roller 3, and one end of the pressure plate 26 is biased by a spring 27 fixed to the shaft 23.

Since the present embodiment has the above-mentioned configuration, the cassette 2
When a large number of sheets S ... Are stacked on the inner plate 12 and inserted / mounted from a not-shown attachment / detachment port of the copying machine, the pressure cam 2
5, the pressure cam 25 rotates (counterclockwise in the illustrated example) along the front inclined surface 11f of the side plate 11a of the cassette body 11, whereby the shaft 23 also rotates counterclockwise. . Further, the spring 27, one end of which is fixed to the shaft 23, is also rotated, and the pressing plate 26 is also rotated by the spring 27. Then, the middle plate 12 of the cassette 2 is pushed up by the pressure plate 26, whereby the sheets S stacked on the middle plate 12 are pressed against the feeding roller 5. Then, the pressure cam 25 further rotates along the inclined surface 11f of the side plate 11a, and the tip 25a rises to the upper surface of the side plate 11a. Then, the tip end 25a of the pressure cam 25 is attached to the side plate 11
The cassette 2 is fixed by engaging with the groove 11c at the tip of a. At this time, the tip portion 25a of the pressure cam 25 is attached to the arm cassette 2
1, the arm plate 15 is also pushed down to take the standby position, and the feeding of the sheet S is not blocked. On the other hand, when the cassette 2 is pulled out from the main body of the copying machine, the tip end 25a of the pressing arm 25 is disengaged from the groove 11c, and then the inclined surface 11f of the side plate 11a of the cassette main body 11 is lowered. As a result, the pressure plate 26 is de-energized, the middle plate 12 descends, and the arm cam 21 is released and rises. Further, the arm plate 15 integrally with the arm cam 21 is raised to the regulation position to regulate the conveyance direction of the sheet S, and the cassette 2
The arm plate 15 can regulate the sheet S that is about to jump out of the front plate of the cassette 2 by the reaction force that works against the force of pulling out the sheet from the copying machine main body.

(G) Effect of the Invention As described above, according to the present invention, the sheet regulating member regulates the movement of the sheet in the sheet feeding direction when the sheet storage device is pulled out from the sheet feeding device. When the storage device is mounted, the sheet can be supplied without any trouble, but when the sheet storage device is separated from the image forming apparatus, the sheet can be prevented from jumping out in the transport direction.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sheet storage device according to the present invention, FIG. 2 is a front view showing a main part of the sheet storage device, FIG. 3 is a perspective view showing a sheet storage device and a lift device, and FIG. 5 is a front view showing a sheet feeding device including a sheet storage device, FIG.
The figure is a front view showing a conventional example. 2 ... Sheet storage device, 5 ... Sheet feeding means, 11a
... side plate, 12 ... middle plate (sheet mounting portion), 15 ... arm plate (sheet regulating member), 17 ... leaf spring (biasing means), 25 ... pressing member (pressing means).

Claims (1)

[Claims] 1. A sheet feeding device in which a sheet storing device for storing sheets to be fed by a sheet feeding means is detachably provided, wherein the sheets stacked on a sheet placing portion of the sheet storing device are A lifter unit which is pressed against the sheet feeding unit and releases the pressure according to the detachment of the sheet storage device, and a sheet feeding direction which is arranged on the front side in the sheet feeding direction of the sheets stacked on the placing unit. A sheet regulating member movable to a regulation position for regulating the movement of the sheet and a standby position not regulating the sheet, an urging unit for urging the sheet regulating member to maintain the sheet at the regulating position, and the sheet storage device. Pressing means for pressing the sheet regulating member against the urging force of the urging means to move it from the regulating position to the standby position according to the mounting operation of the sheet accommodating device. A sheet feeding apparatus wherein sheet regulating member Rutoki is characterized by regulating the sheet by moving the restricting position from the standby position by the biasing means.