JP3548486B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly, to a sheet feeding apparatus that feeds a sheet to an image forming unit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a sheet on which an image is to be formed is housed in a cassette which is detachably mounted on the apparatus main body, and the sheet is sheeted by a feeding mechanism provided in the apparatus main body. Some are configured to be taken out and fed to the image forming unit one by one.
[0003]
By the way, in the case of an apparatus which is required to use various types of sheets, separately from the above-described cassette, a sheet storing portion for storing and storing various types of sheets, and a sheet stored and stored in the sheet storing portion are provided. There is a case where a multi-feeding device provided with a feeding means for feeding to the image forming section is provided.
[0004]
[Problems to be solved by the invention]
However, in the conventional image forming apparatus having such a multi-feeding device, the multi-feeding device occupies a large space in the image forming device including the feeding unit, and thus hinders downsizing of the image forming device. . Also, the number of parts increases.
[0005]
In order to reduce the size of the multi-feeding device, for example, a guide member is provided in a part of the sheet feeding cassette instead of providing a feeding unit, and sheets are set one by one on the guide member and fed. Although it may be configured to feed paper, this configuration can set only one sheet at a time, and there is a problem in use as an image forming apparatus in a networked environment.
[0006]
Accordingly, the present invention has been made in view of such a situation, and an object of the present invention is to provide an image forming apparatus that can use various types of sheets, and that can be reduced in size and number of parts. To do.
[0007]
[Means for Solving the Problems]
According to the present invention, a cassette for storing sheets is detachably attached to the lower side of the apparatus main body, and a feeding roller provided in a sheet feeding apparatus provided on the apparatus main body side is stored in the cassette. In the image forming apparatus that supplies an image to a sheet by supplying the sheet to the image forming unit by rotating while abutting on the sheet, a drawer side end of the cassette that is different from a sheet storage unit of the cassette is provided. A second sheet feeding device provided with a pickup roller for sending out a sheet to the image forming unit by rotating while contacting a sheet stored in the second sheet storage unit; The sheets stored in the cassette and the sheets stored in the second sheet storage unit are respectively separated from the lower side of the apparatus main body by the image forming apparatus. While fed toward the forming unit, the feeding direction of the sheet by the feed roller is characterized in that the feeding direction of the sheet by the pickup roller in the reverse direction is set.
[0008]
Further, the invention is characterized in that the second sheet storage portion is provided in the cassette.
[0009]
Further, the present invention is characterized in that the second sheet storage section is provided in the apparatus main body.
[0010]
Further, the present invention is characterized in that the front second sheet storage portion is provided in the apparatus main body so as to be movable between a position for storing sheets and a standby position for not storing sheets.
[0011]
Further, the present invention is characterized in that a drive transmitting means for driving the second sheet feeding apparatus by a driving means provided in the apparatus main body is provided.
[0012]
Further, according to the present invention, the second sheet feeding device includes a pickup roller for feeding the sheet, and an elevating plate movable between a position where the sheet is pressed by the pickup roller and a position where the pressing is released. And rotation of the pickup roller and raising and lowering of the lift plate are performed by driving of the drive means.
[0013]
Further, in the present invention, the drive transmission means has a gear train on the apparatus main body side and a gear train on the cassette side, and the gear train is connected according to mounting of the cassette on the apparatus main body. It is characterized by the following.
[0014]
Further, the invention is characterized in that the second sheet feeding device is integrally provided in the cassette.
[0015]
Further, the present invention is characterized in that the second sheet feeding device is detachably provided on the cassette.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a diagram showing a schematic configuration of a printer which is an example of an image forming apparatus according to a first embodiment of the present invention.
[0018]
In the figure, reference numeral 40 denotes a printer, and 41 denotes a printer main body (hereinafter, referred to as a main body). The printer 40 is housed in the image forming section 3, the fixing means 8, the feeding means C, and the main body 41. And a paper feed cassette A, which is a selected cassette.
[0019]
Here, the image forming unit 3 includes a photosensitive drum 4 that is an image carrier that rotates in the direction of an arrow, an optical system 5 that irradiates a laser beam to the drum surface according to image information to form a latent image, The image forming apparatus includes developing means 6 for developing the image into a visible image by toner development, and a transfer roller 7 for transferring the toner image to the sheet S.
[0020]
The sheet cassette A is detachably mounted on the main body 41 and includes a cassette tray 10 serving as a sheet storage unit for stacking and storing sheets S, a separation claw 12, and a transport roller 21. Further, at a drawer side end of the sheet cassette A, a multi-sheet feeding device B which is a second sheet feeding device provided with a multi-tray 13 which is a second sheet storage portion different from the cassette tray 10 is provided. Are provided integrally.
[0021]
Further, the feeding means C includes a feeding roller 11 for feeding out the sheets S stacked and stored on the cassette tray 10, and a driving unit (not shown) for driving the feeding roller 11, After the picked-up sheet S is picked up by the feeding roller 11, the sheet S is conveyed by the conveying roller 21 while being separated one by one by the separation claw 12, and is fed to the image forming unit 3 via the registration roller 1. ing.
[0022]
On the other hand, the multi-feeding device B integrated with the cassette tray 10 is provided with a pickup roller 15 serving as a feeding unit that regulates the sheets S in the width direction and feeds out the sheets S stacked on the multi-tray 13 to be stacked. A separation pad 16 that separates the sheets S sent by the pickup roller 15 one by one, and a transport roller 22 are provided. Then, the sheets S stacked on the multi-tray 13 are conveyed by the conveying roller 22 while being separated one by one by the cooperation of the pickup roller 15 and the separation pad 16, and fed to the image forming unit 3 via the registration roller 1. It is supposed to be.
[0023]
Next, an image forming operation in the printer 40 configured as described above will be described.
[0024]
At the time of image formation, first, the surface of the photosensitive drum 4 rotating in the direction of the arrow is uniformly charged, and thereafter, the charged drum surface is irradiated with laser light in accordance with image information by the optical system 5 so that the drum surface is irradiated. Is exposed to form a latent image, and the latent image is developed into a visible image by developing the toner with developing means 6.
[0025]
Next, by applying a bias voltage to the transfer roller 7, the visualized toner image is transferred from the cassette tray 10 by the feed roller 11, the transport roller 21 and the registration roller 1, or the multi-tray 13 To the sheet S conveyed by the pickup roller 15, the conveyance roller 22 and the registration roller 1. After the toner image is transferred in this manner, the sheet S is conveyed to the fixing unit 8, and the toner image is heated and fixed on the sheet S by the fixing unit 8, and then provided on the upper surface of the main body 41 by the discharge roller 9. The paper is discharged to the discharged paper discharge unit 42.
[0026]
The sheet cassette A is detachable as described above, and when storing the sheet S in the cassette tray 10, the sheet cassette A is pulled out from the main body in the direction of the arrow in FIG. After that, the paper cassette A is pushed into the main body 41.
[0027]
Incidentally, the pickup roller 15 and the transport roller 22 of the multi-feeding device B are driven by driving means provided on the main body 41. By providing the drive means for driving the multi-feeding device B in the main body 41 in this way, in other words, by not providing the driving means in the multi-feeding device B, the multi-feeding device B and the Can be downsized, and the printer itself can be downsized.
[0028]
On the other hand, FIG. 3 is a diagram illustrating a configuration of a drive unit (drive transmission unit) for driving the multi-feeding device B by a driving unit provided in the apparatus main body. In the present embodiment, the driving unit is configured to also drive the transport roller 21 provided in the sheet cassette A.
[0029]
In the figure, 71 is a motor as a driving source, 70a and 70b are transmission gears, 72 is a coupling gear, and 73 is a passive gear provided in the paper cassette A. When the paper cassette A is mounted on the main body 41, As shown in the figure, a passive gear 73 provided in the paper feed cassette A meshes with a connection gear 72 on the main body side. Thus, the rotation of the motor 71 is transmitted to the passive gear 73 via the transmission gears 70a and 70b and the connection gear 72.
[0030]
Here, a driving gear 75 for driving the conveying roller 21 provided in the sheet cassette A is meshed with the passive gear 73, so that when the motor 71 rotates when the sheet cassette A is mounted, When the roller 21 is driven and the sheet S stored in the cassette tray 10 is sent out, the sheet S sent from the feeding roller 11 can be conveyed toward the registration roller 1.
[0031]
On the other hand, a driving gear 77 for driving the transport roller 22 on the multi-feeding device side is meshed with the passive gear 73. When the motor 71 rotates, the transport roller 22 is driven, and the When sending out the stored sheet S, the sheet S sent from the pickup roller 15 can be conveyed toward the registration roller 1.
[0032]
Incidentally, the rotation of the drive gear 77 is transmitted to a pickup drive gear 79 for driving the pickup roller 15 via an idler gear 78 for adjusting the rotation direction.
[0033]
Here, as shown in FIG. 4, the pickup driving gear 79 is fixed to the rotating shaft 80 of the pickup roller 15 and is rotatably attached to the rotating shaft 80 with a missing tooth driving gear 79a having a missing tooth portion 79d. On the other hand, the toothless drive gear 79a is urged in the rotation direction by the coil spring 81, and is constituted by a toothless clutch gear 79b having a toothless portion 79d and a claw shape 79c for controlling the rotation of the pickup drive gear 79. Have been.
[0034]
In the same figure, an arm 82 is swingably attached to a rotating shaft 73a of the passive gear 73. One side of the arm 82 has a claw of a pickup driving gear 79 (a toothless clutch gear 79b). A claw portion 82a locked to the shape 79c is formed.
[0035]
Then, as shown in the figure, by locking the claw portion 82a with the claw shape 79c of the pickup drive gear 79, the rotation of the pickup drive gear 79 is restricted. In the figure, reference numeral 83 denotes a tension spring, and the arm 82 is urged by the tension spring 83 in a direction for locking the claw portion 82a with the claw shape 79c of the pickup driving gear 79.
[0036]
Here, when the rotation is restricted by the arm 82, the toothless portion 79d of the pickup drive gear 79 is at a position facing the idler gear 78. For this reason, in this state, even if the idler gear 78 rotates together with the drive gear 77, the pickup drive gear 79 does not rotate.
[0037]
On the other hand, as will be described later, the other end 82b of the arm 82 is pressed by a solenoid (not shown) or the like, and the arm 82 swings counterclockwise while resisting the spring force of the tension spring 83. The portion 82a comes off the claw shape 79c of the pickup drive gear 79.
[0038]
Then, when the claw portion 82a of the arm 82 comes off in this manner, the toothless clutch gear 79b rotates by the force of the coil spring 81 which has been contracted so far, and meshes with the idler gear 78. Thus, the rotation of the idler gear 78 is transmitted to the toothless clutch gear 79b, and the toothless clutch gear 79b rotates.
[0039]
Further, when the toothless clutch gear 79b rotates in this way, the coil spring 81 expands, whereby the rotation of the toothless clutch gear 79b is transmitted to the toothless drive gear 79a, and the pickup drive gear 79 rotates. The rotation shaft 80 to which the roller 15 is fixed rotates.
[0040]
Here, a cam 85 for controlling a lifting plate 84 that presses the sheets S stacked on the multi-tray 13 against the pickup roller 15 is attached to the rotating shaft 80 of the pickup roller 15 as shown in FIG. I have. Accordingly, when the pickup roller 15 is rotated by the rotation of the rotating shaft 80, the cam 85 attached to the rotating shaft 80 and the interlocking plate 86 for transmitting the movement of the cam 85 to the elevating plate 84 raise the elevating plate 84. The sheet S stacked on the multi-tray 13 is pressed by the pickup roller 15.
[0041]
By the way, when the pickup driving gear 79 rotates about one turn, the toothless portion 79d of the toothless driving gear 79a comes to face the idler gear 78, whereby the rotation of the idler gear 78 is not transmitted to the pickup driving gear 79. .
[0042]
However, when the pickup roller 15 rotates, the pressing force of the elevating plate 84 and the forces of the interlocking plate 86 and the return damper 87 are applied to the cam 85 from below, so that the rotating shaft 80 moves the idler gear. Even if the rotation of the rotation 78 is not transmitted, the rotation of the lifting plate 84 transmitted through the cam 85 and the force of the interlocking plate 86 and the return damper 87 are performed.
[0043]
In the present embodiment, the force acting on the other end 82b of the arm 82 is released until the rotation shaft 80 starts rotating by the force transmitted via the cam 85. As a result, the claw portion 82a of the arm 82 returns to the position where the claw shape 79c of the pickup drive gear 79 (the toothless clutch gear 79b) is locked by the bias of the tension spring 83.
[0044]
As a result, after the rotation of the idler gear 78 is stopped being transmitted, when the pickup roller 15 is rotated by the rotating shaft 80 which is rotated by the force transmitted via the cam 85, the pickup driving gear 79 is rotated as shown in FIG. Is locked to the claw portion 82a of the arm 82, and the rotation of the pickup drive gear 79 is restricted.
[0045]
Next, a sheet feeding operation using the multi-feeding device B in the printer 40 configured as described above will be described.
[0046]
When the motor 71 rotates after the paper cassette A is mounted on the main body 41, the rotation of the motor 71 is reduced by the transmission gears 70a and 70b and the coupling gear 72, and then rotated in the direction of the arrow shown in FIG. The power is transmitted to the passive gear 73 on the side of the paper feed cassette meshed with 72. As a result, the passive gear 73 and the drive gears 75 and 77 meshing with the passive gear 73 rotate, and the transport roller 21 that transports the sheet S of the cassette tray 10 and the transport roller 22 on the multi-feed device start rotating. .
[0047]
Here, when feeding the sheet S stored in the cassette tray 10, the claw portion 82a of the arm 82 urged by the tension spring 83 as shown in FIG. Since the clutch gear 79b is engaged with the claw shape 79c of the toothless clutch gear 79b), the rotation of the pickup drive gear 79 is restricted. At this time, the toothless portion 79d of the pickup drive gear 79 is located at a position facing the idler gear 78 as shown in FIG.
[0048]
Therefore, even if the drive gear 77 rotates and the idler gear 78 meshing with the drive gear 77 rotates, the idler gear 78 and the pickup drive gear 79 do not mesh with each other. Thus, the drive is not transmitted to the pickup drive gear 79, and the pickup roller 15 does not rotate.
[0049]
On the other hand, when the sheet S is sent out from the multi-feeding device B, a solenoid (not shown) provided on the main body 41 operates according to a sheet feeding instruction from a main body control unit (not shown), and as shown in FIG. The arm 82 swings counterclockwise about the rotation shaft 73a of the passive gear 73 as a fulcrum. Thereby, the claw portion 82a of the arm 82 is disengaged from the claw shape 79c of the toothless clutch gear 79b. Thereafter, the force of the coil spring 81 rotates the toothless clutch gear 79b and meshes with the idler gear 78.
[0050]
Further, when the idler gear 78 and the missing tooth clutch gear 79b mesh with each other due to the rotation of the missing tooth clutch gear 79b, the rotating shaft 80 to which the pickup roller 15 is fixed rotates, and the pickup roller 15 rotates. When the rotating shaft 80 rotates in this manner, the lift plate 84 moves by the action of the cam 85 and the interlocking plate 86 attached to the rotating shaft 80.
[0051]
As a result, the sheets S stacked on the multi-tray 13 are pressed by the pickup roller 15, and when the pickup roller 15 rotates in this state, the sheet S is taken out and cooperated with the separation pad 16. The sheets are separated one by one and sent to the transport roller 22.
[0052]
After feeding the sheet S, the pickup driving gear 79 rotates by the rotation of the idler gear 78 and the force transmitted via the cam 85. Thereafter, the claw shape 79c is locked to the claw portion 82a of the arm 82, which has already returned to the position shown in FIG. 4 by the urging force of the tension spring 83, and the toothless portion 79d is rotated to a position facing the idler gear 78. By doing so, the rotation of the pickup drive gear 79 is regulated. With such a series of operations, the intermittent rotation operation of the pickup roller 15 of the multi-feeding device B becomes possible.
[0053]
By the way, as described above, by driving the pickup roller 15 and the transport roller 22 of the multi-feeding device B by the driving unit provided on the main body 41, and by controlling the electric power of the solenoid and the like used for the rotation control. Even if the multi-feeding device B is provided, paper feeding can be performed even when the multi-feeding device B is provided by making all electrical connections within the main body and eliminating the need for electrical connection between the main body 41 and the paper feeding cassette A. The structure of the cassette A can be simplified, and the number of parts can be reduced.
[0054]
Further, by not providing the driving means in the multi-feeding device B, the multi-feeding device B and the paper feed cassette A having the same can be downsized as described above. The size can be reduced.
[0055]
On the other hand, in the present embodiment, as shown in FIG. 7, the frame A1 of the sheet cassette A has a monocoque structure made of one molding material so as to integrate the sheet cassette A and the multi-feeding device B. I have. By integrating the sheet cassette A and the multi-feeding device B in this manner, the number of components can be reduced, and cost reduction can be realized.
[0056]
Note that the configuration of the sheet cassette A is not limited to the one shown in the figure, and for example, as shown in FIG. 8, a frame A1 of the sheet cassette A and a frame B1 of the multi-feeding device B are divided and The frames A1 and B1 may be integrated by fastening means such as screws.
[0057]
By dividing the frames A1 and B1 in this way, that is, by providing the multi-feeding device B in the sheet feeding cassette A so as to be detachable, the sheet storage of the sheet feeding cassette A such as an optional sheet feeding cassette It can be diverted to a cassette that requires only a part (cassette tray 10), so that the types of parts can be reduced and the space for unnecessary functions can be reduced.
[0058]
Further, as a configuration of the sheet feeding cassette A, the multi-tray 13 of the multi-feeding device B is provided rotatably (movable) on the main body 41 as shown in FIG. The tray 13 may be used by rotating it downward.
[0059]
With such a configuration, when the multi-feeding device B is not used, the multi-tray 13 can be stored in the main body, and space can be saved. By not providing the multi-tray 13 in the paper feed cassette A, the weight of the paper feed cassette A can be reduced.
[0060]
【The invention's effect】
As described above, as in the present invention, by providing the sheet feeding device in the cassette which is detachably mounted on the apparatus main body, various types of sheets can be used, and the sheet feeding device is provided. Even in this case, it is possible to reduce the size of the apparatus and the number of parts.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a printer as an example of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a state in which a paper cassette of the printer is pulled out.
FIG. 3 is a diagram illustrating a configuration of a driving unit that drives a multi-feeding device provided in the paper feed cassette.
FIG. 4 is a diagram showing a state when the multi-feeding device of the driving unit is not used.
FIG. 5 is a side sectional view of the multi-feeding device.
FIG. 6 is a diagram showing a state when the multi-feeding device of the driving unit is used.
FIG. 7 is a diagram illustrating a configuration of the paper feed cassette.
FIG. 8 is a diagram illustrating another configuration of the paper feed cassette.
FIG. 9 is a diagram illustrating another configuration of the paper feed cassette.
[Explanation of symbols]
3 Image forming unit 10 Cassette tray 11 Feed roller 13 Multi tray 15 Pickup roller 40 Printer 41 Printer body 71 Motor 72 Drive gear 73 Passive gear 78 Idler gear 79 Pickup drive gear A Paper cassette B Multi feeder C Feeder throw S sheet

Claims (9)

A cassette for storing sheets is detachably mounted on the lower side of the apparatus main body , and a feeding roller provided in a sheet feeding apparatus provided on the apparatus main body side contacts a sheet stored in the cassette. In an image forming apparatus that forms an image on a sheet by supplying a sheet to an image forming unit by rotating in contact with the image forming unit,
At the drawer side end of the cassette, there is provided a pickup roller for feeding a sheet to the image forming unit by rotating while contacting a sheet stored in a second sheet storage unit different from a sheet storage unit of the cassette. A second sheet feeding device is provided, and a sheet stored in the cassette and a sheet stored in the second sheet storing portion are respectively disposed below the device main body by the feeding roller and the pickup roller. And a sheet feeding direction set by the pickup roller in a direction opposite to a sheet feeding direction by the feeding roller . The image forming apparatus according to claim 1, wherein the second sheet storage unit is provided in the cassette. The image forming apparatus according to claim 1, wherein the second sheet storage unit is provided in the apparatus main body. The image forming apparatus according to claim 3, wherein the second sheet storage unit is provided on the apparatus main body so as to be movable between a position where a sheet is stored and a standby position where no sheet is stored. 2. The image forming apparatus according to claim 1, further comprising a drive transmission unit for driving the second sheet feeding device by a driving unit provided in the apparatus main body. The second sheet feeding device includes a pickup roller for feeding a sheet, and an elevating plate movable between a position where the sheet is pressed against the pickup roller and a position where the pressing is released, and the driving unit includes: 6. The image forming apparatus according to claim 5, wherein the rotation of the pickup roller and the raising / lowering operation of the lifting / lowering plate are performed by driving the lifting roller. The drive transmission means includes a gear train on the apparatus main body side and a gear train on the cassette side, and the gear train is connected according to the mounting of the cassette on the apparatus main body. Item 6. The image forming apparatus according to Item 5. 2. The image forming apparatus according to claim 1, wherein the second sheet feeding device is provided integrally with the cassette. 2. The image forming apparatus according to claim 1, wherein the second sheet feeding device is detachably provided on the cassette.

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