JP2005015202A - Sheet feed device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a sheet feed device by reducing the number of drive sources such as a drive motor and reducing a drive force in the sheet feed device. <P>SOLUTION: This sheet feed device is formed so that a plurality of sheet storage parts are arranged along the sheet carrying direction and sheets are fed selectively from the plurality of sheet storage parts to a sheet transport route. A first sheet feedout unit feeds out the sheets from the sheet storage part positioned on the upstream side in the sheet carrying direction, and a second sheet feedout unit feeds out the sheets from the sheet storage part positioned on the downstream side in the sheet carrying direction to the sheet transport route. A sheet guide unit transports the sheets fed out from the first sheet feedout unit to the second sheet feedout unit by the first sheet feedout unit and carries the sheets to the sheet transport route. When the first sheet feedout unit is driven by the first drive source, a drive force from the second drive source is transmitted to the sheet guide unit through a drive force transmission mechanism, and the transmission of the drive force from the second drive source to the second sheet feedout unit is stopped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding device used for an image forming apparatus such as a copying machine, a printer, or a facsimile machine, for feeding a sheet such as a recording sheet.
[0002]
[Prior art]
In general, a sheet feeding device used in an image forming apparatus includes a plurality of sheet storage units, and selectively feeds sheets from these sheet storage units. Some are arranged in parallel (horizontally) along the direction.
[0003]
In such a sheet feeding apparatus, for example, a sheet storage unit (hereinafter referred to as a downstream sheet storage unit) located on the downstream side in the sheet conveyance direction and a sheet storage unit (hereinafter referred to as an upstream sheet storage unit) positioned on the upstream side in the sheet conveyance direction. And upstream and downstream sheet feeding units (feeding units) corresponding to the upstream and downstream sheet storage units, respectively.
[0004]
Further, the sheet sent from the downstream sheet storage unit is transported by the upstream transport unit (conveyance unit) to the image forming unit for image formation, and the sheet sent from the upstream sheet storage unit is transported to the downstream transport unit Therefore, it passes through the upper part of the downstream sheet feeding unit and merges with the upstream conveying unit (see Patent Document 1).
[0005]
In the sheet feeding device described in Patent Document 1, each of the upstream and downstream sheet feeding units includes a sheet feeding roller and a sheet feeding roller, and in each of the upstream and downstream sheet feeding units, The sheet feeding roller and the sheet feeding roller are connected to a driving source so as to rotate in the sheet feeding direction by a drive transmission means.
[0006]
[Patent Document 1]
JP 9-20434 A (paragraph (0023) to paragraph (0027), FIGS. 1 to 3)
[0007]
[Problems to be solved by the invention]
By the way, in the conventional sheet feeding apparatus, when feeding the sheet from the upstream sheet storage unit by driving the feeding roller and the sheet feeding roller by the respective driving sources in the upstream and downstream sheet feeding units. Are joined to the upstream transport section via the downstream transport section.
[0008]
In other words, when feeding a sheet from the downstream sheet storage unit, the downstream sheet feeding unit drives the feed roller and the paper feed roller to send the sheet to the upstream transport unit, and the sheet from the upstream sheet storage unit In the upstream sheet feeding unit, the feed roller and the feed roller are driven, and the downstream side conveyance unit is driven with the conveyance roller and the like. There is a problem that a driving source such as a driving motor is enlarged and the sheet feeding apparatus itself is enlarged.
[0009]
An object of the present invention is to provide a small sheet feeding device by reducing the driving force of a driving source such as a driving motor.
[0010]
[Means for Solving the Problems]
According to the present invention, sheet feeding includes a plurality of sheet storage units arranged in parallel along the sheet transport direction, and selectively feeds sheets from the plurality of sheet storage units to a sheet transport path for image formation. In the apparatus, a first sheet delivery unit that sends out the sheet from a sheet storage unit located on the upstream side in the sheet conveyance direction, and a sheet storage unit located on the downstream side in the sheet conveyance direction from the sheet to the sheet conveyance path. A second sheet delivery unit to be sent, and a sheet sent by the first sheet delivery unit from the first sheet delivery unit to the second sheet delivery unit side to convey the sheet A sheet guide unit that is transported to the path, a first drive source that drives the first sheet delivery unit, and the second sheet delivery unit. And a second driving source for driving the sheet guide unit, and a driving force transmission mechanism for selectively transmitting the driving force from the second driving source to the sheet guide unit or the second sheet feeding unit. A sheet feeding apparatus characterized by having the sheet feeding device is obtained.
[0011]
In this way, if the driving force from the second driving source is selectively transmitted to the sheet guide unit or the second sheet feeding unit, the number of driving sources can be reduced, and the driving of the driving sources can be reduced. The force can be reduced, and the sheet feeding apparatus can be reduced in size.
[0012]
In the present invention, the driving force transmission mechanism transmits the driving force from the second driving source to the sheet guide unit when the first sheet feeding unit is driven by the first driving source. The transmission of the driving force from the second driving source to the second sheet feeding unit is stopped, for example, the second driving source rotates in a predetermined direction and the predetermined direction. A driving shaft that is rotationally driven in a reverse direction, and the driving force transmission mechanism transmits the driving force to the second sheet feeding unit when the driving shaft is rotationally driven in the predetermined direction; Is rotated in the opposite direction, the driving force is transmitted to the sheet guide unit.
[0013]
As described above, when the first sheet feeding unit is driven by the first driving source, the driving force from the second driving source is transmitted to the sheet guide unit by the driving force transmission mechanism, so that the second driving is performed. If the transmission of the driving force from the source to the second sheet delivery unit is stopped, the number of drive sources is reduced without impairing the conveyance of the sheet sent from the first sheet delivery unit, In addition, the driving force of the driving source can be reduced, and the sheet feeding apparatus can be reduced in size.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to the description unless otherwise specified. It is just an example.
[0015]
First, an image forming apparatus using a sheet feeding apparatus according to the present invention will be described with reference to FIG. In the following description, a sheet feeding device will be described as an example of the sheet feeding device. The illustrated image forming apparatus 10 includes a sheet feeding device 11 that is a sheet feeding device, and the sheet feeding device 11 is mounted on an image forming apparatus casing (hereinafter simply referred to as an apparatus casing) 10a. A recording sheet (sheet: hereinafter simply referred to as a sheet) is conveyed from the sheet feeding device 11 to the image forming unit 13 via a sheet conveying path 12 (a sheet conveying roller 12a and a registration roller 12b).
[0016]
For example, the image forming unit 13 includes a photosensitive drum 13a. Around the photosensitive drum 13a, a charger 13b, a developing unit 13c, a transfer roller 13d, a cleaning device 13e, and the like are arranged. After 13a is uniformly charged by the charger 13b, the photosensitive drum 13a is exposed according to image data by an exposure unit (not shown) to form an electrostatic latent image.
[0017]
Thereafter, the electrostatic latent image is developed by the developing device 13c to form a toner image on the photosensitive drum 13a, and this toner image is transferred onto a sheet by the transfer roller 13d. The toner remaining on the photosensitive drum 13a is removed by the cleaning device 13e.
[0018]
The paper is sent to the fixing roller pair 15 by the transport belt 14 where the toner image on the paper is fixed. During single-sided printing, the paper that has passed through the fixing roller pair 15 is discharged by a paper discharge roller pair 16 onto a paper discharge tray (not shown).
[0019]
In the illustrated image forming apparatus 10, a double-sided printing unit 17 is disposed between the paper feeding device 11 and the image forming unit 13. When performing double-sided printing, the paper that has passed through the fixing roller pair 15. Is sent to the double-sided printing unit 17, where the paper is reversed and then sent again to the paper transport path 12 through the reverse path 17a, and the paper is transferred to the image forming unit 13 via the paper transport path 12. Will be sent. Then, the double-sided printed paper is discharged to the paper discharge tray by the paper discharge roller pair 16.
[0020]
As shown in FIG. 1, the paper feeding device 11 includes first and second paper storage units (paper trays) 21 and 22, and the first and second paper storage units 21 and 22 include the first and second paper storage units 21 and 22. Although not shown, a large number of sheets are stored, and each time the sheets are conveyed, the bottom plates 21a and 22a move upward to position the uppermost sheet at a predetermined position.
[0021]
In the illustrated example, a paper feeding unit 23 is arranged between the first and second paper storage units 21 and 22 and the duplex printing unit 17, and the paper feeding unit 23 selectively selects the first paper feeding unit 23. A sheet is conveyed from the first and second sheet storage units 21 and 22 to the sheet conveyance path 12.
[0022]
The first paper storage unit 21 is positioned upstream of the second paper storage unit 22 in the paper transport direction, and the first and second paper storage units 21 and 22 are horizontally aligned along the paper transport direction. The first and second paper storage portions 21 and 22 are detachably arranged in the apparatus housing 10a. For example, when paper is replenished, the first and second paper storage portions 21 and 22 are pulled out from the back side to the front side in FIG. It is.
[0023]
2 and 3 are also diagrams schematically showing the paper feeding device 11 from above, and FIG. 3 is a schematic sectional view of the paper feeding device 11. The paper feeding unit 23 includes first and second paper feeding units 31 and 32 and a paper guide unit 33. The first and second paper feeding units 31 and 32, the paper guide unit 33, and the like. Is integrally supported by the unit housing 34.
[0024]
The first and second paper delivery units 31 and 32 correspond to the first and second paper storage units 21 and 22, respectively. The first and second paper delivery units 31 and 32 will be described later. In this way, the paper guide unit 33 communicates.
[0025]
As shown in FIGS. 2 and 3, the first paper feed unit 31 includes a pickup roller 31a, a paper feed roller 31b, and a separation roller 31c. The paper feed roller 31b and the separation roller 31c are in contact with each other. Is in a state. The paper feed roller 31 b is attached to one end side of the rotating shaft body 41, and a gear 42 is attached to the other end side of the rotating shaft body 41. The gear 42 meshes with a gear 43 a attached to the motor shaft of the first drive motor (first drive source) 43, and the first drive motor 43 is supported by the unit housing 34.
[0026]
The rotary shaft body 41 is rotatably supported by a support stay 44 provided in the unit casing 34. Further, the support stay 44 rotatably supports a rotary shaft body 45, and one end side thereof. In addition, a pickup roller 31a is supported and a gear 45a is mounted. A gear 46 is rotatably supported by the support stay 44, and a gear 47 attached to one end side of the rotary shaft body 41 meshes with the gear 46, and the gear 46 meshes with the gear 45a. Although not shown, the separation roller 31c is rotatably supported by the support stay 44 described above.
[0027]
Similarly, the second paper feed unit 32 includes a pickup roller 32a, a paper feed roller 32b, and a separation roller 32c, and the paper feed roller 32b and the separation roller 32c are in contact with each other. The paper feed roller 32 b is attached to one end side of the rotating shaft body 51 via a so-called one-way gear 52, and a gear 53 is attached to the other end side of the rotating shaft body 51. The gear 74 is meshed with a gear 54 a mounted on the motor shaft of the second drive motor (second drive source) 54. The second drive motor 54 is supported by the unit housing 34.
[0028]
The rotary shaft body 51 is rotatably supported by a support stay 55 provided in the unit casing 34. Further, the support stay 55 rotatably supports a rotary shaft body 56, and has one end side thereof. The pickup roller 32a is supported and a gear 56a is mounted. A gear 57 is rotatably supported by the support stay 55, and a gear 52 mounted on one end side of the rotating shaft 51 is engaged with the gear 57, and the gear 57 is engaged with the gear 56a. Although not shown, the separation roller 32c is rotatably supported by the support stay 55 described above.
[0029]
In the paper guide unit 33, a conveyance path 33a (see FIG. 3) is formed, and one end side (left side in FIG. 3) of the conveyance path 33a communicates with the exit side of the paper feed roller 31b and the separation roller 31c. The other end passes through the upper side of the second paper delivery unit 32 and joins the delivery side of the paper feed roller 32b and the separation roller 32c. The paper guide unit 33 includes first transport rollers 61a and 61b and second transport rollers 61c and 61d. The first transport rollers 61a and 61b are attached to the rotary shaft 62, and the second transport rollers 61a and 61b are mounted on the rotary shaft body 62. The transport rollers 61 c and 61 d are attached to the rotating shaft 63. The rotating shaft bodies 62 and 63 are rotatably supported by the unit housing 34.
[0030]
As shown in FIG. 3, the first driven rollers 64a and 64b are in contact with the first transport rollers 61a and 61b, respectively. Similarly, the second transport rollers 61c and 61d are respectively connected to the second transport rollers 61c and 61b. The driven rollers 64c and 64d are in contact. The first and second driven rollers 64a to 64d face the first and second transport rollers 61a to 61d, respectively, across the transport path 33a.
[0031]
Although not shown, the first driven rollers 64a and 64b are rotatably supported by the shaft, and similarly, the second driven rollers 64c and 64d are also rotatably supported by the shaft. In FIG. 2, the first and second driven rollers 64a to 64d are omitted for convenience of explanation.
[0032]
Pulleys 65 and 66 are mounted on the rotary shaft bodies 62 and 63, respectively (mounted on the upper end side of the rotary shaft bodies 62 and 63 in FIG. 2A), and between the pulleys 65 and 66, respectively. A timing belt 67 is stretched. Further, in the illustrated example, a gear 63 a is attached to the upper end side of the rotary shaft 63. The gear 63a meshes with the one-way gear 71. The one-way gear 71 is held at one end of the shaft body 71a, and the gear 72 is attached to the other end of the shaft body 71a (not shown, but the shaft body 71a is, for example, The unit housing 34 is rotatably supported).
[0033]
The gear 72 meshes with the gear 73, and the gear 73 meshes with the gear 74 (not shown, but the gears 73 and 74 are rotatably supported by the unit housing 34). The gear 74 meshes with the gear 54a of the second drive motor 54 as described above.
[0034]
Here, referring to FIGS. 2 to 4 (in FIG. 4, the sheet conveying direction is opposite to that in FIG. 3. That is, FIG. 3 is a cross-sectional view when the sheet feeding device 11 is viewed from the front side. Yes, FIG. 4 is a view when viewed from the back side), and the first and second drive motors 43 and 54 described above are driven and controlled by a drive control device (not shown). In FIG. 4, the pickup roller 32a is omitted.
[0035]
Now, when the sheet is fed from the second sheet storage unit 22 located downstream in the transport direction to the image forming unit, the second drive motor 54 is driven to rotate in the forward direction by the drive control unit, and the gear 54a rotates in the forward direction (the direction indicated by the solid arrow A in FIG. 4). As a result, the gear 74 rotates in the direction indicated by the solid arrow A, and the rotating shaft 51 rotates. The aforementioned one-way gear 52 is a gear that can rotate only in one direction, and when the second drive motor 54 is driven to rotate forward, that is, when the gear 74 rotates in the direction indicated by the solid line arrow A, The one-way gear 52 rotates, whereby the paper feed roller 32b rotates in the direction indicated by the solid line arrow A. Further, the pickup roller 32a (not shown in FIG. 4) is rotated by the rotation of the one-way gear 52.
[0036]
As a result, a sheet is picked up from the second sheet storage unit 22 by the pickup roller 32a, and the uppermost sheet is separated by the separation roller 32c, and the sheet conveyance path 12 (FIG. 1) is separated by the sheet feeding roller 32b. To be sent).
[0037]
On the other hand, the rotation of the gear 74 (the direction indicated by the solid arrow A) causes the gear 72 (not shown in FIG. 4) to rotate via the gear 73, whereby the rotary shaft 71a is indicated by the solid arrow A. The one-way gear 71 held by the rotating shaft 71a is rotated in the direction indicated by the solid arrow A when the second drive motor 54 is driven in the forward direction (that is, the gear 74 is in the direction indicated by the solid arrow A). When rotating, the rotating shaft 71a is idled (that is, the one-way gear 71 does not transmit rotational driving in the direction indicated by the solid line arrow A).
[0038]
Thus, when the second drive motor 54 is driven to rotate forward, the one-way gear 71 causes the rotary shaft 71a to idle so that the driving force is transmitted to the first and second transport rollers 61a to 61d. The first and second transport rollers 61a to 61d do not rotate. That is, the paper guide unit 33 is not driven.
[0039]
When the paper is fed from the first paper storage unit 21 located upstream in the paper transport direction to the image forming unit, the drive control device controls the first drive motor 43 to rotate forward and the second The drive motor 54 is reversely driven.
[0040]
By the normal rotation drive of the first drive motor 43, the gear 43 a is rotationally driven in the direction indicated by the solid line arrow, and the rotary shaft body 41 rotates through the gear 42. As a result, the paper feed roller 31b rotates in the direction indicated by the solid line arrow, and the pickup roller 31a rotates through the gear 45 and the gear 46. A sheet is picked up from the first sheet storage unit 21 by the pickup roller 31a, and the uppermost sheet is separated by the separation roller 31c. The sheet is conveyed by the sheet feeding roller 31b (see FIG. 3). Is sent out.
[0041]
The reverse drive of the second drive motor 54 causes the gear 54a to rotate in the direction indicated by the solid line arrow B, thereby rotating the rotary shaft 51. As described above, the one-way gear 52 is Since the rotational force is transmitted only when the second drive motor 54 is rotated forward (when the gear 54a rotates in the direction indicated by the solid line arrow A), the rotary shaft 51 is idled by the one-way gear 52 after all. Thus, the paper feed roller 32b and the pickup roller 32a do not rotate. That is, the second paper feeding unit 32 is not substantially driven.
[0042]
On the other hand, when the gear 54a rotates in the direction indicated by the solid line arrow B, the gear 72 rotates through the gear 73, whereby the rotary shaft 71a rotates in the direction indicated by the solid line arrow B. The one-way gear 71 transmits a rotational force (driving force) when the second drive motor 54 is driven in reverse (that is, when the gear 74 rotates in the direction indicated by the solid line arrow B), The rotation of the rotary shaft 71a is transmitted to the gear 63a.
[0043]
As a result, the rotating shaft 63 rotates and the second transport rollers 61c and 61d rotate. The rotation of the rotating shaft 63 is transmitted to the rotating shaft 62 via the timing belt 67, and the first conveying rollers 61a and 61b rotate (that is, the paper guide unit 33 is driven). . As a result, the sheet sent to the transport path 33a by the first paper feed unit 31 is transported to the downstream side by the first and second transport rollers 61a to 61d to the paper transport path 12 (see FIG. 1). Will be sent out.
[0044]
In this way, the first paper feed unit 31 is driven by the first drive motor 43, and the second paper feed unit 32 and the paper guide unit 33 are selectively driven by the second drive motor 54. Only when the first paper delivery unit 31 is being driven, the paper guide unit 33 is driven by the second drive motor 54 so that the second paper delivery unit 32 is substantially stopped. The number of drive sources such as a drive motor can be reduced and the drive force of the drive source can be reduced, so that the paper feeding device can be reduced in size.
[0045]
In the above description, the example in which the first and second paper storage units 21 and 22 are horizontally arranged along the paper conveyance direction has been described. However, the first paper storage is not necessarily required to be horizontally arranged. If the section 21 is located upstream of the second sheet storage section 22 in the sheet transport direction, the first and second sheet storage sections 21 and 21 are selectively selected by the sheet feeding unit 23 as described above. When feeding paper from 22, the number of drive sources such as a drive motor can be reduced.
[0046]
As is clear from the above description, each of the gears and the one-way gear described above constitutes a drive transmission mechanism.
[0047]
【The invention's effect】
As described above, in the present invention, the driving force from the second driving source is selectively transmitted to the sheet guide unit or the second sheet feeding unit by the driving force transmission mechanism. As a result, the driving force of the driving source can be reduced, and the sheet feeding apparatus can be reduced in size.
[0048]
In the present invention, when the first sheet feeding unit is driven by the first driving source, the driving force transmission mechanism transmits the driving force from the second driving source to the sheet guide unit, so that the second driving is performed. Since the transmission of the driving force from the source to the second sheet sending unit is stopped, the number of driving sources is reduced without impairing the conveyance of the sheet sent from the first sheet sending unit, In addition, the driving force of the driving source can be reduced, and the sheet feeding apparatus can be reduced in size.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically illustrating an image forming apparatus in which an example of a sheet feeding device which is a sheet feeding device according to the present invention is used.
FIG. 2 is a diagram schematically showing the paper feeding device shown in FIG. 1 from above.
FIG. 3 is a cross-sectional view showing the paper feeding device shown in FIG. 1 from the side.
4 is a diagram for explaining an operation of a paper feeding unit of the paper feeding device shown in FIG. 1; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Paper feeder 12 Paper conveyance path 13 Image forming part 14 Conveyor belt 15 Fixing roller pair 16 Paper discharge roller pair 17 Duplex printing units 21 and 22 Paper storage part 23 Paper feeding units 31 and 32 Paper sending unit 33 Paper guide unit 34 Unit housing 43 First drive motor (first drive source)
54 Second drive motor (second drive source)

Claims (3)

In a sheet feeding apparatus that includes a plurality of sheet storage units arranged in parallel along the sheet transport direction, and selectively feeds sheets from the plurality of sheet storage units to a sheet transport path for image formation.
A first sheet delivery unit for delivering the sheet from a sheet storage unit located upstream in the sheet conveying direction;
A second sheet delivery unit for delivering the sheet from the sheet storage unit located on the downstream side in the sheet conveyance direction to the sheet conveyance path;
A sheet guide unit that conveys the sheet delivered by the first sheet delivery unit from the first sheet delivery unit to the second sheet delivery unit and delivers the sheet to the sheet delivery path;
A first drive source for driving the first sheet delivery unit;
A second drive source for driving the second sheet feeding unit and the sheet guide unit;
A sheet feeding apparatus comprising: a driving force transmission mechanism that selectively transmits a driving force from the second driving source to the sheet guide unit or the second sheet feeding unit. The driving force transmission mechanism transmits the driving force from the second driving source to the sheet guide unit when the first sheet feeding unit is driven by the first driving source. 2. The sheet feeding apparatus according to claim 1, wherein transmission of driving force from the driving source to the second sheet feeding unit is stopped. The second drive source includes a drive shaft that rotates in a predetermined direction and is driven to rotate in a direction opposite to the predetermined direction,
The driving force transmission mechanism transmits driving force to the second sheet feeding unit when the driving shaft is rotationally driven in the predetermined direction, and when the driving shaft is rotationally driven in the reverse direction, The sheet feeding device according to claim 2, wherein the driving force is transmitted to a guide unit.

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