JPH1129226A - Paper feeding cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize to manufacture at low costs a structure for preventing the occurrence of impact sound caused by the lifting/suspending of a bottom plate when a cassette is mounted to a device main body. SOLUTION: A rotary type damper such as a rotary wing type damper transmitting clamping force by its rotating shaft 32a and the like, is used as a hydraulic type damper 32 to be arranged in a cassette main body 3. A pinion 33 is fixed to the rotating shaft 32a of the hydraulic type damper 32, and the pinion 33 is meshed with a rack 34 formed around a pivot 4a in the supporting part 4b of a bottom plate 4. For this reason, when a cassette 31 is mounted to a device main body, the lifting speed of the bottom plate 4 is lowered by the damping force of the hydraulic type damper 32, and impact force is thereby restrained when a recording sheet over the bottom plate 4 collides against a separation pawl 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed cassette which is detachably mounted on a paper feeder for feeding recording paper to an image recording apparatus such as a facsimile machine, a printer, a copying machine or the like, and stores recording paper. .

[0002]

2. Description of the Related Art FIG. 4 is a schematic diagram of a facsimile apparatus which is an example of an image forming apparatus having a paper feeder, and FIG.
1 is a configuration diagram of a conventional paper feed cassette detachably attached to the paper feed device shown in FIG. Reference numeral 1 denotes an apparatus main body of a facsimile apparatus in which a paper feeding apparatus is configured as a part of the apparatus, 2 denotes a paper feeding cassette detachably mounted at a lower portion of the apparatus main body 1, and 3 denotes a paper feeding cassette. The housing-shaped cassette body 4 to be housed is a bottom plate which is arranged at the bottom of the cassette body 3 and is supported so as to be swingable about a support shaft 4a. The placed recording paper is placed. Numeral 5 is interposed between the cassette body 3 and the bottom plate 4, and its urging force (elastic force generated at the time of deformation recovery).
A spring for urging the bottom plate 4 upward by the lower plate 4 is provided with separation claws 6 disposed at both ends in the paper width direction in the cassette main body 3.
The two corner portions on the leading end side of the recording paper placed above are respectively engaged. Reference numeral 7 denotes a slide claw arranged on the bottom surface of the cassette main body 3, which is supported by the cassette main body 3 so as to be slidable in the attaching / detaching direction with respect to the apparatus main body 1, and which is not shown in the drawing. Are biased in the mounting direction. The slide claw 7 is formed with a drive projection 7a protruding from the front surface of the cassette body 3 in the mounting direction.
A pressing member 8 is provided corresponding to.

Here, when the bottom plate 4 swings to the lower limit position against the spring 5, the slide claw 7 locks the bottom plate 4 as shown by a two-dot chain line in FIG. Therefore, by holding the bottom plate 4 at the lower limit position by the slide claw 7 outside the apparatus main body 1,
The work of placing the recording paper on the bottom plate 4 in the cassette body 3 can be facilitated. Further, the sheet cassette 2 in a state where the bottom plate 4 is restrained at the lower limit position is moved to the apparatus main body 1.
The slide claw 7 is released by the slide claw 7 when the drive protrusion 7a is pressed by the pressing member 8 and the slide claw 7 slides. As a result, the bottom plate 4
Swing upward by the urging force of the spring 5.

On the other hand, in the apparatus main body 1, reference numeral 10 denotes a paper feed roller supported above the paper feed cassette 2, and a chordwise flat portion 10a is formed on the outer peripheral surface of the paper feed roller 10. By causing the flat portion 10a to face the recording paper on the bottom plate 4 at the time of non-separated paper feeding, interference between the paper feeding cassette 2 detachably mounted on the apparatus main body 1 and the paper feeding roller 10 is prevented. Reference numerals 11 and 12 denote a pair of conveying rollers and a pair of registration rollers arranged along a paper conveying path (not shown). Reference numeral 13 denotes a rotatable photosensitive drum 14 and a charger, a developing device, An image forming unit in which a cleaning device and the like are arranged, 15 is an optical writing unit, 16 is a photosensitive drum
Reference numeral 14 denotes a transfer roller, 17 denotes a fixing device including a heating roller and a pressure roller, and 18 denotes a paper discharge roller pair disposed at the end of the paper transport path. Reference numeral 20 denotes a document loading unit provided on the upper surface of the apparatus main body 1, and reference numeral 21 denotes a scanner unit for reading an image of a document loaded in the document loading unit 20.

Next, a description will be given of a separating sheet feeding operation and an image forming operation for recording paper in the facsimile apparatus configured as described above. After the recording paper is stored in the paper feed cassette 2 in which the bottom plate 4 is restrained at the lower limit position by the slide claw 7, the paper feed cassette 2 is mounted on the apparatus main body 1 so that the bottom plate 4 is moved to the slide claw 7 as described above. And is swung upward by the urging force of the spring 5. The bottom plate 4 is held by the separation claw 6 at a position where the leading edge of the recording paper is hooked. Therefore, the height of the bottom plate 4 is displaced in accordance with the remaining number of recording sheets, but the recording sheet on the bottom plate 4 is always kept at a constant height by the separation claws 6.

When image formation is started after the sheet cassette 2 is completely mounted, the photosensitive drum 14 charged to a predetermined potential by the charger in the image forming unit 13 corresponds to image information from the optical writing unit 15. An electrostatic latent image is formed by scanning with the laser light. The developing unit develops the electrostatic latent image into a toner image by selectively attaching toner to the photosensitive drum 14 in accordance with the charged potential of the electrostatic latent image.

On the other hand, when the image formation on the photosensitive drum 14 is started, the torque from a drive motor (not shown) is transmitted to the paper feed roller 10, and the paper feed roller 10 rotates a predetermined amount of rotation (usually, One rotation). Thus, the paper feed roller 10 presses the circumferential portion 10b against the uppermost sheet of recording paper, and pushes out the recording paper in the paper feeding direction by frictional force. At this time, one or a plurality of recording papers extruded by the paper feed roller 10 receive conveyance resistance from the separation claw 6, so that the uppermost one sheet on which the maximum conveyance force is applied by the paper feed roller 10 is applied. Only the recording paper is separated and gets over the separation claw 6, and another recording paper is held in the paper feed cassette 2. The recording paper fed from the paper feed cassette 2 into the paper transport path is transported along the paper transport path by the transport roller pair 11 and reaches the registration roller pair 12. This recording paper is
After abutting against the nip portion of the registration roller pair 12 and temporarily stopping, the conveyance is started again by the registration roller pair 12 at the timing when the leading end of the toner image on the photosensitive drum 14 moves to a predetermined position, and the photosensitive drum is exposed by the transfer roller 16. The toner image on the body drum 14 is transferred. The recording paper to which the toner image has been transferred is heated and pressed by the fixing device 17 so that the toner image is fixed, and after the fixing is completed, the recording paper is discharged to the outside of the apparatus main body 1 by the discharge roller pair 18.

[0008]

In the paper feeder used in the facsimile apparatus described above, the paper feed cassette 2 is mounted on the apparatus main body 1, and the bottom plate 4 swings upward by the urging force of the spring 5, The separation pawl 6 holds the recording paper at a position corresponding to the number of recording papers. At this time, the rising speed of the bottom plate 4 changes according to the urging force of the spring 5 and the weight of the recording paper, but the spring 5 is set so that the pressure contact force with the paper feed roller 10 becomes appropriate. Because quite strong
(Having a large elastic coefficient) is used. Therefore, the bottom plate 4
Rises at high speed and generates a large impact force when the recording paper collides with the separation claw 6. When the paper cassette 2 is mounted on the apparatus main body 1 in a state where the recording paper is not placed on the bottom plate 4 for the purpose of storing the paper cassette 2, the bottom plate 4 directly contacts the separation claw 6. Because of the collision, the impact force is even greater. With the generation of such an impact force, a loud impact sound is leaked to the outside of the apparatus main body 1, and there is a problem that the quietness in an office or the like is impaired.

In order to solve the problem when the paper feed cassette 2 is mounted on the apparatus main body 1, for example, Japanese Utility Model Laid-Open No. 60-187136 discloses a method in which a weight is arranged on a mounting plate (bottom plate), and this weight is used. A paper feed cassette supported movably in a radial direction about a support shaft of a mounting plate is described. In this paper cassette, by adjusting the position of the weight according to the type of recording paper and the number of sheets to be placed, it is possible to offset the excess urging force of the spring and to make the urging force acting on the mounting plate appropriate. Although it is possible, the weight must be adjusted according to the type of recording paper and the number of sheets to be placed, which makes the operation complicated and reduces the impact force when the recording paper collides with the separation claw. However, it is difficult to reduce the impact sound leaking to the outside of the apparatus main body to a sufficient level. In addition to the paper cassette disclosed in Japanese Utility Model Application Publication No. 60-187136, there is also a conventional paper feeder or paper cassette equipped with a means for preventing or suppressing an impact sound when the paper cassette is mounted. Each of them has a complicated structure, so that it is difficult to apply them to other than high-end models in terms of cost.

Some paper feeders do not use the separation claw 6. For example, a paper feed cassette is mounted on the main body of the apparatus, and the bottom plate urged upward is released to allow the recording paper on the bottom plate to be released. By pressing against the roller surface of the paper feed roller,
This is for positioning the recording paper in the height direction. But,
Even in such a configuration, the impact sound when the recording paper on the bottom plate collides with the paper feed roller becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by providing a low-cost paper feed cassette in which a structure for preventing an impact sound generated by raising / stopping a bottom plate when mounted on an apparatus main body is realized. Is to provide.

[0012]

According to a first aspect of the present invention, there is provided a paper feed cassette, comprising: a paper storage body for storing a bundle of recording papers; A bottom plate that is movably supported in the loading direction and on which the bundle of recording paper stored in the paper storage body is placed; an elastic body that urges the bundle of recording paper upward through the bottom plate; A separating claw that locks the leading end of the recording sheet urged upward by the paper feeding direction, and restrains the bottom plate at a lower limit position in the stacking direction against the urging force of the elastic body, and mounts the bottom plate on the apparatus main body. And a restraint mechanism for releasing the bottom plate in conjunction with the operation performed, the paper storage body is provided with a buffer means for generating a damping force due to the movement resistance of the working fluid, and the buffer means is provided with the bottom plate. To the bottom plate that moves upward by the biasing force of the elastic body. Characterized in that the action of the damping force by.

According to the paper feed cassette of the present invention, the paper storage body is provided with a fluid type buffer means, and this buffer means is connected to the bottom plate to be moved upward by the urging force of the elastic body. By applying a damping force to the apparatus, when the paper cassette is mounted on the apparatus main body, the rising speed of the bottom plate is reduced by the damping force of the buffer means, so that the bottom plate or the recording paper on the bottom plate collides with the separation claw. The impact force at the time is suppressed.

According to a second aspect of the present invention, in the sheet cassette of the first aspect, the buffer means is constituted by a hydraulic damper using hydraulic oil as a hydraulic fluid.

According to the paper feed cassette of the second aspect, by using the hydraulic damper as the buffer means, the greater the force acting on the bottom plate, the greater the damping force is generated, and the force acting on the bottom plate is reduced. It is possible to reduce the damping force that is generated with the decrease.

According to a third aspect of the present invention, there is provided the paper feed cassette according to the first or second aspect, wherein a support member for supporting the buffer means is provided on the paper storage body, and the buffer means is provided by the support member. The movable member is supported so as to be movable in the vertical direction, and the movable stroke of the support member with respect to the buffering means is slightly larger than the vertical displacement of the bottom plate at the time of separating and feeding.

According to the paper feed cassette of the third aspect, the buffer means is movably supported in the vertical direction by the support member provided in the paper storage body, and the movable stroke of the support member relative to the buffer means is reduced. By slightly increasing the vertical displacement of the bottom plate at the time of separation paper feeding, when the paper feed roller is pressed against the recording paper on the bottom plate, the bottom plate takes priority around the connecting shaft within the range of the movable stroke by the support member And the damping force of the buffer means is prevented from acting on the bottom plate.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a paper feed cassette according to an embodiment of the present invention. FIG. 2 is a configuration diagram showing an example of a main part of the paper feed cassette according to the embodiment of the present invention. The same reference numerals are given to members corresponding to the members described based on the above, and the description thereof will be omitted in the following description. Reference numeral 31 denotes a paper feed cassette. This paper feed cassette 31 is configured to be detachable from a lower portion of the apparatus main body 1 of the facsimile apparatus shown in FIG. Numeral 32 denotes a hydraulic damper arranged in the cassette body 3 as a paper storage body. As the hydraulic damper 32 as a buffer means, a rotary damper such as a rotary airfoil damper transmitting a damping force by a rotary shaft 32a is used. Is used. Such a hydraulic damper 32 uses, for example, silicon oil as a working fluid, and has an orifice formed in a partition partitioning a plurality of hydraulic chambers, so that silicon oil pressurized by an airfoil piston moving in the hydraulic chamber is used. Due to the pressure drop when passing through the orifice, a damping force is generated on the rotating shaft 32a fixed coaxially with the airfoil piston.

Reference numeral 33 denotes a pinion fixed to the rotating shaft 32a;
Is a rack formed around the support shaft 4a in the support portion 4b of the bottom plate 4, and the pinion 33 and the rack 34 mesh with each other. As a result, the hydraulic damper 32
A damping force is applied to the bottom plate 4 swinging about the support shaft 4a via the pinion 33 and the rack 34.

Next, the operation of the sheet cassette 31 configured as described above will be described. When storing recording paper in the paper feed cassette 31, the paper feed cassette 31 is pulled out of the apparatus main body 1, and
The bottom plate 4 is swung to the lower limit position against the spring 5.
Here, as a characteristic of the hydraulic damper 32, the larger the force acting on the bottom plate 4, that is, the higher the speed of swinging the bottom plate 4, the larger the damping force is generated, and the force acting on the bottom plate 4 is reduced. And the generated damping force also decreases. Therefore, when the user swings the bottom plate 4 to the lower limit position at a low speed, the damping force by the hydraulic damper 32 is slight, and the workability at this time is almost the same as that of the conventional sheet cassette 2.

By swinging the bottom plate 4 to the lower limit position, the bottom plate 4 is restrained by the slide claws 7, so that the user can easily place the recording paper on the bottom plate 4. After the recording paper is placed at a predetermined position on the bottom plate 4, the paper feed cassette 31 is mounted on the apparatus main body 1, whereby the drive projection 7 a
Is pressed by the pressing member 8 of the apparatus main body 1, and the slide claw 7 releases the bottom plate 4. At the same time, the urging force of the spring 5 acts on the bottom plate 4, but the hydraulic damper 32 exerts a damping force corresponding to the urging force of the spring 5.
The rising speed of the bottom plate 4 is reduced in accordance with the damping force of the hydraulic damper 32, and is significantly lower than when only the urging force of the spring 5 acts.

As described above, according to the paper feed cassette 31 of the present embodiment, when the paper feed cassette 31 is mounted on the apparatus main body 1, the rising speed of the bottom plate 4 is reduced by the damping force of the hydraulic damper 32. By doing so, the impact force at the time of collision between the recording paper on the bottom plate 4 and the separation claw 6 is suppressed, so that it is possible to prevent the generation of an impact sound at the time of collision between the recording paper on the bottom plate 4 and the separation claw 6. In addition, the impact noise can be sufficiently reduced to a level that does not impair the quietness of the installation environment. Furthermore, in the paper feed cassette 31 of the present embodiment, since only the hydraulic damper 32 and the coupling mechanism between the hydraulic damper 32 and the bottom plate 4 are added to the configuration of the conventional paper feed cassette 2,
The cost increase is also slight.

By connecting the hydraulic damper 32 to the bottom plate 4 as described above, the impact noise when the bottom plate 4 is raised / stopped can be effectively reduced, but the responsiveness of the bottom plate 4 to external force is reduced. This causes a problem. In particular,
When the paper is separated and fed, the paper feed roller 10 comes into pressure contact with the recording paper on the bottom plate 4, so that the bottom plate 4 slightly descends, and the recording paper is pressed against the paper feed roller 10 with a predetermined pressure by the elastic force of the spring 5. Then, the frictional force between the paper feed roller 10 and the recording paper is set to an appropriate magnitude. However, the reversal time from when the bottom plate 4 is once lowered by the paper feed roller 10 to when the bottom plate 4 is raised by the elastic force of the spring 5 is delayed, and the rising speed is reduced, so that the bottom plate 4 follows the paper feed roller 10. And the frictional force between the paper feed roller 10 and the recording paper becomes smaller than an appropriate value. Therefore, the feed roller 10
In the case of a model in which the vertical displacement of the bottom plate 4 is large, the paper feed roller 10 is likely to idle with respect to the recording paper, so that the probability of misfeed increases and the reliability of the separated paper feed may decrease.

Next, FIG. 3 shows a configuration of a main part of the sheet feeding cassette according to the present embodiment to which a configuration for solving the above problem is added. A support member 41 supports the hydraulic damper 32 in the cassette body 3.
Is swingably supported by a connecting shaft 42 erected on the cassette body 3, and has an arc-shaped groove 41 a centered on the connecting shaft 42. A pin 43 implanted in the cassette body 3 is inserted into the groove 41a, and the swing stroke of the support member 41 and the hydraulic damper 32 fixed to the support member 41 is defined by the groove 41a and the pin 43. Have been.
Here, the support member 41 defined by the groove 41a and the pin 43
Is set so as to be slightly larger than the swing amount of the bottom plate 4 generated by the sheet feeding roller 10 at the time of separation sheet feeding. Further, since the distance from the connection shaft 42 to the support shaft 4a is small with respect to the entire length of the bottom plate 4, even when swinging about the support shaft 4a or when swinging about the connection shaft 42, However, the displacement of the movement trajectory of the bottom plate 4 is slight, and does not affect the separation sheet feeding operation.

The bottom plate 4 is urged by the spring 5 and hooked by the separation claw 6 via the recording paper when the paper feed cassette 31 is mounted on the apparatus main body 1.
The pin 43 inserted into the groove 41a is held in a state in which the pin 43 is pressed against the lower end of the groove 41a by the elastic force of the spring 5 in a state in which the sheet feeding is not performed. From this state, when the sheet feeding for the recording sheet is started and the sheet feeding roller 10 is pressed against the recording sheet on the bottom plate 4, the bottom plate 4 causes the swinging stroke of the support member 41 to be generated by the sheet feeding roller 10. Is slightly larger than the amount of displacement of the connecting shaft 42, and thus swings preferentially downward around the connecting shaft 42.

When the bottom plate 4 swings about the connecting shaft 42, no torque acts on the rotating shaft 32a of the hydraulic damper 32. Therefore, the bottom plate 4 is once lowered by the damping force of the hydraulic damper 32. The bottom plate 4 can reliably follow the paper feed roller 10 without delaying the reversal time from rising to rising and without lowering the rising speed of the bottom plate 4. Even with a model in which the amount of vertical displacement of the bottom plate 4 is large, it is possible to prevent the reliability of the separation sheet feeding from being reduced.

In the above description of the paper feed cassette according to the present embodiment, only the one using the separation claw 6 has been described. However, the bottom plate is released in conjunction with the apparatus main body, and an elastic body such as a spring is used. In the case of a paper cassette having a rising bottom plate, the present invention is implemented by connecting a buffering means such as a hydraulic damper to the bottom plate, and further supporting the buffering means by a supporting member so as to be movable within a predetermined range in a vertical direction. Needless to say, the same effect as that of the paper feed cassette 31 of the embodiment can be obtained.

[0028]

As described above, according to the first aspect of the present invention,
According to the paper feed cassette described above, when the paper feed cassette is mounted on the apparatus main body, the ascending speed of the bottom plate is reduced by the damping force of the buffer means, and when the recording paper on the bottom plate or the bottom plate collides with the separation claw. Since the impact force is suppressed, it is possible to prevent the generation of impact noise when the recording paper on the bottom plate collides with the separation claw, and to sufficiently reduce the impact noise to a level that does not impair the quietness of the installation environment it can. Further, in the paper feed cassette according to the first aspect of the present invention, only a buffer means and a coupling mechanism for connecting the buffer means and the bottom plate are added to the configuration of the conventional paper feed cassette. The rise is also slight.

According to the paper feed cassette of the second aspect, by using a hydraulic damper as the buffer means,
When a large force acts on the bottom plate, a large damping force is generated, and the force acting on the bottom plate is reduced and the generated damping force can be reduced. By reducing the damping force of the hydraulic damper to a small level, it is possible to prevent the workability when storing the recording paper in the paper feed cassette from deteriorating.

According to the paper feed cassette of the third aspect, a support member for supporting the buffer means is provided in the paper storage body, and the buffer means is supported by the support member so as to be movable in the vertical direction. The movable stroke with respect to the buffer means is slightly larger than the vertical displacement amount of the bottom plate at the time of separation paper feeding, so that when the paper feeding roller is pressed against the recording paper on the bottom plate, the movable stroke is within the range of the movable stroke by the support member. Since the bottom plate swings preferentially around the connecting shaft and the damping force by the buffering means can be prevented from acting on the bottom plate, the reversal time from when the bottom plate once drops to when it rises is delayed, The lowering speed of the bottom plate does not decrease, and the bottom plate can reliably follow the feed roller. As a result, for example, in a model in which the vertical displacement of the bottom plate by the feed roller is large, , It is possible to prevent the reliability of the separation sheet feeding is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a paper feed cassette according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a main part of the paper feed cassette according to the embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating another example of a main part of the sheet cassette according to the embodiment of the present invention;

FIG. 4 is a schematic configuration diagram of a facsimile machine which is an example of an image forming apparatus provided with a paper feeding device.

5 is a configuration diagram of a conventional paper feed cassette detachably mounted on the paper feed device shown in FIG.

[Explanation of symbols]

3 ... cassette body, 4 ... bottom plate, 4a ... support shaft, 4b ...
Supporting portion, 5: Spring, 6: Separating claw, 7: Slide claw, 7a: Driving projection, 8: Pressing member, 10: Feed roller, 31: Feed cassette, 32: Hydraulic damper,
32a: rotating shaft, 33: pinion, 34: rack, 41: support member, 41a: groove, 42: connecting shaft, 43: pin.

Claims (3)

[Claims] 1. A paper storage body for storing a bundle of recording paper, and the paper storage body is movably supported by the paper storage body in a stacking direction of the recording paper, and a stack of the recording paper stored in the paper storage body is placed thereon. A bottom plate, an elastic body for urging the bundle of recording paper upward through the bottom plate, a separation claw for hooking a leading end of the recording paper urged upward by the elastic body in a paper feeding direction, A sheet cassette provided with a restraining mechanism that restrains the bottom plate at a lower limit position in the stacking direction against the urging force of an elastic body and releases the bottom plate in conjunction with an operation of being mounted on the apparatus main body; A buffering means for generating a damping force by the movement resistance of the working fluid is provided in the housing, and the buffering means is connected to the bottom plate, and the damping force acts on the bottom plate moving upward by the urging force of the elastic body. A paper cassette characterized by being made to work. 2. The paper cassette according to claim 1, wherein the buffer means is constituted by a hydraulic damper using hydraulic oil as a working fluid. 3. A supporting member for supporting the buffering means is provided on the paper storage body. The supporting member movably supports the buffering means in the up-down direction, and the movable stroke of the supporting member with respect to the buffering means at the time of separation sheet feeding. 2. The vertical displacement of the bottom plate is slightly larger than that of the first embodiment.
Or the sheet cassette according to claim 2.