JP3690318B2 - Paper cassette - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feed cassette in which an urging force by an urging member can be appropriately switched in accordance with the state of a sheet stacked on a bottom plate that supports the sheet.
[0002]
[Prior art]
In general, in an image forming apparatus such as an electrophotographic copying machine or a facsimile machine, a paper feeding cassette that stores paper of an arbitrary size is arranged in a paper feeding unit. A plurality of sheets are stacked and stored in the sheet feeding cassette, and the sheets are separated one by one using a sheet feeding roller of a sheet feeding device provided in a sheet feeding unit and a sheet separating means such as a separation claw. However, it is sent to the image recording unit. A side guide or an end guide is provided in the paper storage portion of the paper feed cassette as a position regulating member for regulating the rear end portion and both side surfaces in the paper feeding direction. After the paper is set in the paper storage device, the restricting member is fixed at the restricting position to press and fix the both side portions and the rear end portion of the paper. The paper is regulated so that it does not shift.
[0003]
In the paper feeding cassette, a bottom plate on which paper is loaded is supported so as to be swingable around a fulcrum provided on a side plate of the cassette housing, and a paper feed side tip of the bottom plate is placed between the cassette bottom plate and the bottom plate. The spring is arranged in the. The bottom plate is fixed to the paper feed cassette in a lowered state, the paper is stacked on the plate, the leading end is locked to the separation claw, and the paper feed cassette is fed to the image forming apparatus. Attach to the part. In the final portion of the paper cassette, when the latch with respect to the bottom plate is released, the paper is lifted together with the bottom plate by the urging force of the spring, and the front end of the paper is pressed against the paper feed roller.
[0004]
[Problems to be solved by the invention]
However, since the conventional paper feed cassette is provided with means for urging the paper toward the paper feed roller by using one kind of spring arranged on the front end side of the bottom plate, Since the weight applied to the bottom plate is different between the size paper and the small size paper, the pressing force of the paper against the paper feed roller is different. In view of this, it has been considered to provide a second spring as a second elastic member in addition to the first spring disposed on the front end side of the bottom plate. In addition, the second spring is operated in a state where the end guide is fixed to a predetermined size so that the urging force (the pressing force against the paper feed roller) corresponding to the weight of the paper can be exhibited. There is also. However, a problem remains that a paper feed cassette that operates the second spring in correspondence with the end guide cannot be operated for small-size paper. On the other hand, even when small-size paper is set in the paper feed cassette, the paper is provided on the bottom plate for thick paper such as glossy paper, or for heavy sheets such as an OHP sheet. In many cases, the weight borne by the first spring, that is, the weight borne by the bottom plate, is almost the same value as that of a large-size sheet. Further, the weight that the first spring bears is larger in the lateral feed of the B5 size paper than in the case of the vertical feed of the A4 size paper (the length direction of the paper is the feeding direction). However, when the second spring is actuated by the end guide in correspondence with the vertical feed of B4 size paper, the bottom on which the B5 size paper is loaded, though it bears almost the same weight. The second spring cannot be applied to the plate.
[0005]
The present invention focuses on the fact that the weight borne by the bottom plate corresponds to the size in the width direction of the paper, and switches the second elastic member provided in the paper feed cassette to the operating state in conjunction with the movement of the side guide. The object is to provide a paper feed cassette that makes it possible.
[0006]
[Means for Solving the Problems]
The present invention comprises a bottom plate for placing paper stored in a paper feed cassette housing;
An end guide that regulates the rear end of the stored paper in the paper feeding direction; and a pair of side guides that regulate both sides of the paper in the paper feeding direction;
A first elastic member that pushes up the bottom plate;
And a second elastic member for assisting the urging force of the first elastic member.
In addition to the first elastic member that pushes up the bottom plate, the invention of claim 1 is provided with a second elastic member for assisting the urging force of the first elastic member,
The second elastic member is configured to be swung in a state of pushing up the bottom plate by a push-up rib provided on one arm member of the side guide,
It is configured to be operated by a pushing rib provided on one arm member of the side guide so as to push up the bottom plate of the second elastic member following the position where the side guide is moved. It is characterized by.
[0007]
According to a second aspect of the present invention, the second elastic member is provided with a lower surface protruding member, and the protruding height of the lower surface protruding member can be arbitrarily set.
The protrusion height of the lower surface protrusion member is configured such that the second elastic member does not act when the remaining amount of paper placed on the bottom plate decreases below a certain level.
According to a third aspect of the present invention, the second elastic member is configured by a leaf spring, and the leaf spring is interlocked so as to be switched between an operating position and a non-operating position in accordance with the movement of the side guide. It is characterized in that the leaf spring is made to perform an upward push-up action by moving the side guide.
[0008]
Since the paper feed cassette is configured as described above and the urging force of the second elastic member is switched according to the paper quality, the number of sheets, and the size of the stored paper, only the first elastic member or the first By the elastic member and the second elastic member, the bottom plate can be pushed up to press the upper surface of the paper against the paper feed roller with an appropriate pressure. Further, since the urging force of the second elastic member is switched by the side guide, when the length of the paper in the paper feeding direction is short but the weight applied to the bottom plate is large, the second elastic member is By applying an urging force to the sheet, the upper surface of the sheet can be pressed against the sheet feeding roller with an appropriate pressure.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the paper feed cassette of the present invention will be described according to the example shown in the drawing. The example shown in FIGS. 1 and 2 shows a plan view and a side view of the paper feed cassette, and FIG. 3 shows a plan view with the bottom plate removed. It is configured as a so-called universal type paper feed cassette that can accommodate paper. The sheet feeding cassette 20 is set such that the sheet feeding direction X is set at a right angle with respect to the mounting direction Y in the sheet feeding unit of the image forming apparatus. A handle 23 is provided on the front side of the casing 21. A pair of leg members 24, 24a on both sides project from the front side of the mounting side, and the guide members are provided with the leg members 24, 24a in the paper feeding unit when being attached to or detached from the paper feeding unit of the image forming apparatus. (Guide 19 shown in FIG. 5) is guided to move the paper feed cassette by the paper feed unit.
[0010]
A bottom plate 30 is swingably provided in the paper storage unit 25 of the paper feed cassette 20 via hinges 31, 31 a, and a paper is set on the bottom plate 30, and the front end in the paper feeding direction X is set. The front plate 22 side arranged in the section can be greatly raised. In order to define the paper to be stored in the paper storage unit 25, an end guide 40 that presses the rear end of the paper delivery side and side guides 50 and 51 that control and press both sides of the paper are provided. The three guide members 40, 50, 51 are provided so as to be capable of being guided along guide portions 27, 28, 28a provided on the bottom plate 26 of the cassette housing 21, and the guide members are fixed at arbitrary positions. Is possible. Further, in the center registration type paper feed cassette that sets the paper feed center with respect to the center of the paper feed cassette, the two side guides 50 and 51 for regulating both sides of the paper are provided along the bottom plate 26. The two side guides 50 and 51 are provided so as to be able to be separated from each other by using an interlocking mechanism.
[0011]
The two side guides 50 and 51 support the separation claws 55 and 56, respectively. With the two side guides 50 and 51 restricting both sides of the paper feeding direction, the separation claws 55 and 56 The corners on both sides of the paper are locked to correspond to the paper separation action. The separation claw 55 holds and holds a substantially triangular flat plate portion at the corners on both sides in the paper feed direction, as is generally used, and separates it from the feed force of the paper feed roller. By engaging the claw 55 with the corner portion of the sheet, the sheet is separated, and the separated sheets can be supplied one by one toward the recording unit of the image forming apparatus. In the paper feed cassette 20, a vertical ridge member 22 a is provided on the inner surface of the front plate 22 in the paper feed direction so that the leading edge of the paper can be brought into contact with the inner surface to facilitate the alignment operation. It is provided and is protected so that the vertical arm of the separation claw is not caught against the paper whose leading end in the paper feeding direction is regulated by the protruding member.
[0012]
As described above, the two side guides 50 and 51 for regulating the both side surfaces of the paper inside the paper feed cassette 20 are formed by using a vertical member that abuts on the side surface of the paper as a flat plate member as described in FIGS. In contrast, they are installed upright. In order to move the two side guides 50, 51 in a direction to move away from each other, a rack is formed on the opposing surfaces of the arm members 52, 53, and the rack is meshed with the pinion 54. Then, by moving one side guide 51 using a handle member 51a provided with a means for locking and releasing, the other side guide 50 is moved and moved away from each other so that both sides of the sheet are moved. Fixing at the pressing position and holding the paper in the restricting position is the same as in the case of a conventional center register type paper feeding cassette.
[0013]
The bottom plate 30 that supports the paper inside the paper feed cassette 20 uses springs 32 and 32a as first elastic members disposed between the bottom plate 26 and the front side of the paper feed side to feed the paper. Pushes up toward the roller. As the first elastic members 32 and 32a, coil springs are used as in the conventional paper feed cassette. In this embodiment, in addition to the first elastic member 32..., The second elastic member 33 is disposed, and the second elastic member 33 is used when the weight of the paper borne by the bottom plate 30 is large. The member 33 is operated together with the first elastic members 32... To assist the action of pushing up the bottom plate 30.
[0014]
Note that the weight applied to the bottom plate changes when the paper is set in the state of A4 portrait (paper feed in the width direction) and A4 landscape (paper feed in the longitudinal direction), and in the case of A4 portrait. The bottom plate is loaded with all the weight of the paper. On the other hand, in the case of A4 lateral feed, the rear end of the paper feed direction is disengaged from the bottom plate, and the center of gravity of the stacked paper is placed near the fulcrum of the bottom plate. The load applied to the urging member via this is also a small value. In addition to the A4 size paper, for the B5 paper, the paper is stacked at a position away from the fulcrum of the bottom plate, that is, the front side of the bottom plate in the feeding direction, and the center of gravity of the paper is also separated from the fulcrum of the bottom plate. In the position. For this reason, the B5 paper has a larger load acting on the spring via the bottom plate than the A4 paper.
[0015]
In the two types of elastic members 32 and 33, when a small-sized paper or a paper whose bottom plate bears a relatively small weight is set on the bottom plate 30, only the first elastic member 32 is operated. Then, the sheet is pressed toward the sheet feeding roller to correspond to sheet feeding. On the other hand, when a heavy sheet such as a large-sized sheet is set on the bottom plate, only the first elastic member 32 has a good force to press the sheet toward the sheet feeding roller. Therefore, by adding the second elastic member 33 to act, the sheet pushing-up action can be performed satisfactorily.
[0016]
The second elastic member 33 is configured as shown in the drawing, and the leaf spring 34 for assisting the pushing force against the bottom plate 30 is arranged in the sheet feeding direction around the hinge portions 36 and 36a. The rear side is attached to a holder 35 that is swingably formed. A lower surface projecting member 37 is provided on the lower surface of the swinging end portion of the holder 35 so as to protrude downward. Following the operation of widening the distance between the two side guides 50 and 51, The front end side is lifted up around the hinge, the front end of the leaf spring 34 is pressed against the bottom plate 30, and the leaf spring 34 and the first elastic member 32 cooperate to push up the paper. . The spring 38 disposed between the holder 35 of the second elastic member 33 and the cassette housing is an urging means for lowering the second elastic member 33 to the non-operating position. Even if 38 is not provided, the second elastic member 33 is lowered by its own weight. When the spring 38 is provided as described above, the two side guides are moved in the approaching direction so that when the push-up rib 58 is removed from the position corresponding to the holder 35, the spring 38 swings. And securely held in the inoperative position.
[0017]
In the present embodiment, as the paper having a large weight borne by the bottom plate 30, as described above, wide and long papers such as A3 and B4 size papers are targeted. In addition, the case of A4, B5 size paper lateral feed, etc. is targeted. In other words, even if a relatively small size paper is stored in the paper feed cassette in the lateral feed state, the bottom plate bears the entire weight of the paper and is directed toward the paper feed roller by the elastic member. Must be pushed up. Therefore, when the both side portions in the paper feeding direction are pressed, the interval between the two side guides 50 and 51 is widened, except in the case of vertical feeding of narrow paper such as A4 size paper. In other words, the second elastic member 33 is automatically operated when the side guide restricts the wide papers in the width direction orthogonal to the paper feeding direction. It is what. Further, the pressing rib 58 that performs the operation of swinging the leaf spring 34 as the second elastic member to the push-up position does not act in a state where the number of sheets is reduced by arbitrarily setting the protruding height. It is also possible to do so. For example, by adjusting the height of the pressing rib 58 and the lower surface protrusion member 37 of the second elastic member 33, the pushing-up action on the leaf spring 34 is eliminated when the remaining amount of paper is about half. By doing so, it is possible to prevent the push-up action by the leaf spring 34 from being applied even when there is little remaining paper.
[0018]
In the paper feed cassette 20 configured as described above, the paper is set on the bottom plate, the end guide 40 is pressed and fixed to the rear end of the paper, and the two side guides are attached to both sides of the paper. 50 and 51 are pressed and fixed. When the range in which the two side guides are moved is outside a predetermined width corresponding to a wide sheet, the push-up rib 58 provided on the arm 53 of the side guide 51 is moved to the second elastic member 33. The holder 35 is engaged with the lower surface of the holder 35 to swing the holder 35 around the hinge 36. Then, the plate spring 34 of the second elastic member 33 is set in a state where it can abut against the lower surface of the bottom plate 30 and perform a push-up action. In the mechanism for operating the second elastic member following the position where the side guide is moved, the target paper size has been described assuming the case of lateral feed such as A4 or B5 size. The paper size can be arbitrarily set, and the push-up force of the second elastic member can also select the type of the leaf spring as appropriate, and the second elastic member can be replaced by a coil spring instead of the leaf spring. May be configured. Further, in the push-up rib provided on the side guide to operate the second elastic member and the lower surface protruding member provided in the holder, the shape and combination structure of each member can be operated well. For example, the present invention is not limited to the illustrated example, and can be appropriately configured.
[0019]
The sheet feeding cassette 20 configured as described above can be mounted on an image forming apparatus configured as shown in FIG. 5 to perform sheet feeding operation. Although the image forming apparatus 1 is shown as an example in which the recording unit 2 and the paper feeding unit 15 to which the paper feeding cassette 20 is mounted are integrally provided, a plurality of paper feeding cassettes can be mounted on the paper feeding unit 15. It can also be configured. In the case where one or a plurality of other paper feeding cassettes can be additionally provided at the lower part of the paper feeding cassette 20 shown in the figure, a cassette mounting portion and a paper feeding device are additionally provided. The paper fed from the paper cassette can be fed by connecting the guide path 18 vertically.
[0020]
In the recording unit 2 of the image forming apparatus 1, a charging member 4, a writing member 5, and a developing roller 7 are arranged on the photosensitive drum 3 around the photosensitive drum 3 that forms a toner image according to the rotation direction. There is provided a developing device 6 that is arranged correspondingly. Further, a transfer roller 8 is disposed across the paper conveyance path 10, and a predetermined value of voltage is applied from the back side of the paper passing through the paper conveyance path 10 to transfer the toner image formed on the photosensitive drum 3. A brush member 9 that disperses the residual toner and weakens the adhesion force of the toner is disposed upstream of the charging member 4.
[0021]
In order to convey the sheet inside the recording unit 2, a sheet conveyance path 10 is arranged, and the sheet is conveyed by the conveyance roller device 12 in synchronization with the toner image formed on the photosensitive drum 3. In the paper transport path 10, the paper fed by the paper feed roller 16 from the paper feed cassette 20 set in the paper feed section 15 is guided toward the paper transport path using the paper guide 17, and the transport roller device 11 is conveyed toward the conveyance roller device 12. Then, in synchronization with the toner image formed on the photosensitive drum 3, the transport roller device 12 is driven to transfer the toner image between the photosensitive drum 3 and the transfer roller 8.
[0022]
In the recording unit 2, the surface of the photosensitive drum 3 is uniformly charged by the charging member 4, and then an image light is irradiated from the writing member 5 to form an electrostatic latent image. Then, toner is supplied from the developing roller 7 to the electrostatic latent image to make a visible image as a toner image. The toner image is transferred from the photosensitive drum 3 toward the paper by applying a voltage of a predetermined value from the back side of the paper, and the paper carrying the toner image is fixed through the fixing device 13. Then, the image is recorded and is deposited by the discharge roller device 14 on the discharge unit provided on the upper surface of the paper supply unit 15.
[0023]
In the paper feeding unit 15, a paper feeding roller 16 is disposed at an upper part on the paper feeding side of the paper feeding cassette. In the paper feeding cassette mounting unit, a guide member used when the paper feeding cassette is attached or detached. 19 and 19a are provided. Then, the leg members 24 and 24a provided in the casing of the sheet feeding cassette and guided members (not shown) formed on both sides of the casing are slid on the guide members 19 and 19a to feed the sheet. Causes the cassette to be attached and detached. Further, in a state where the paper feed cassette 20 is pushed in and stopped, the bottom plate 30 is raised and the upper surface of the paper is pressed against the paper feed roller 16 to cope with the paper feeding operation. A vertical guide path 18 is formed in the frame on the paper feed side of the paper feed unit 15, and, for example, a plurality of paper feed cassette accommodation mechanisms similar to those of the paper feed unit 15 are stacked vertically. In this case, the sheet fed from the lower sheet feeding cassette can be conveyed toward the sheet conveying path 10 of the recording unit via the vertical guide path 18.
[0024]
【The invention's effect】
In the present invention, the paper feed cassette is configured as described above, and the urging force of the second elastic member is switched according to the paper quality, the number of sheets, and the size of the paper to be stored. Alternatively, by the first elastic member and the second elastic member, the bottom plate can be pushed up to press the upper surface of the paper against the paper feed roller with an appropriate pressure. Further, since the urging force of the second elastic member is switched by the side guide, when the length of the paper in the paper feeding direction is short but the weight applied to the bottom plate is large, the second elastic member is By applying an urging force to the sheet, the upper surface of the sheet can be pressed against the sheet feeding roller with an appropriate pressure.
[Brief description of the drawings]
FIG. 1 is a plan view of a paper feed cassette.
FIG. 2 is a side view of a paper feed cassette.
FIG. 3 is an explanatory diagram showing a state where a bottom plate of a paper feed cassette is removed.
FIG. 4 is an explanatory diagram of a mechanism for swinging a second elastic member.
FIG. 5 is an explanatory diagram illustrating a configuration of an image forming apparatus.
[Explanation of symbols]
1 image forming apparatus, 2 recording unit, 3 photosensitive drum,
4 charging member, 5 writing member, 6 developing device,
7 Developing roller, 8 Transfer roller, 10 Paper transport path,
11.12 Conveying roller device, 13. Fixing device,
14 discharge roller device, 15 paper feed unit, 16 paper feed roller,
17 paper guide, 18 guide path, 19 cassette guide,
20 paper cassette, 21 housing, 22 front plate,
23 Handle, 24 Leg member, 25 Paper storage part,
26 bottom plate, 27/28 guide, 30 bottom plate,
31 hinge, 32 first elastic member, 33 second elastic member,
34 leaf spring, 35 holder, 36 hinge,
37 bottom projection member, 38 return spring, 40 end guide,
41 slider, 50/51 side guide,
52/53 arm member, 54 pinion, 55/56 separation claw,
58 Push-up rib.

Claims (3)

A bottom plate for placing paper stored in a paper cassette casing;
An end guide that regulates the rear end of the stored paper in the paper feeding direction; and a pair of side guides that regulate both sides of the paper in the paper feeding direction;
A first elastic member that pushes up the bottom plate;
A paper feeding cassette comprising: a second elastic member for assisting the biasing force of the first elastic member,
In addition to the first elastic member that pushes up the bottom plate, a second elastic member for assisting the biasing force of the first elastic member is provided,
The second elastic member is configured to be swung in a state of pushing up the bottom plate by a push-up rib provided on one arm member of the side guide,
It is configured to be operated by a pushing rib provided on one arm member of the side guide so as to push up the bottom plate of the second elastic member following the position where the side guide is moved. A paper cassette characterized by The second elastic member is provided with a lower surface protruding member, and the protruding height of the lower surface protruding member can be arbitrarily set,
The protrusion height of the lower surface protrusion member is configured such that the second elastic member does not act when the remaining amount of paper placed on the bottom plate decreases below a certain level. The paper feed cassette according to 1. The second elastic member is constituted by a leaf spring;
In response to the movement of the side guide, the leaf spring is interlocked to switch between the operating position and the non-operating position,
The sheet feeding cassette according to claim 1, wherein the leaf spring is configured to perform an upward push-up action by moving the side guide.

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