JP2000062983A - Paper feeder - Google Patents

Abstract

(57) [Problem] To provide a paper feeder having a simple configuration. SOLUTION: A first gear 31 of a first paper feed roller 25,
The second gear 37 of the second paper feed roller 33, a motor 39 that can be driven in forward and reverse rotations, an arm 40 that rotates about a motor shaft 51 in conjunction with the rotation of the motor 39, and drives the motor 39. When the motor shaft 51 rotates forward, the arm rotates in the direction of the first gear 31 so that the transmission gear 57 meshes with the first gear 31 and the motor shaft 51 rotates in the opposite direction. When rotated, it rotates in the direction of the second gear 37 and the transmission gear 57 meshes with the second gear 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device in an image forming apparatus such as a copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art Generally, in a paper feeding device having a plurality of paper feeding cassettes, a paper feeding roller for feeding paper from each paper feeding cassette is arranged in each paper feeding cassette. Such a sheet feeding device requires a motor for driving the sheet feeding roller for each sheet feeding cassette, and thus has a problem that the configuration becomes complicated.

On the other hand, Japanese Unexamined Patent Publication No. 7-215500 discloses a technique in which one of the two paper feed cassettes drives only one of the paper feed rollers to feed the paper by the forward and reverse rotation of one motor. Is.

More specifically, two shafts of the paper feed rollers are respectively equipped with one-way clutches which can rotate only in opposite directions, and drive only one of the paper feed rollers according to the rotation direction of the motor. It is a technology that is being made.

[0005]

However, in the above-mentioned technique, the one-way clutch has to be mounted on the shaft of each paper feed roller, so that there is a problem that the structure becomes complicated.

[0006] Therefore, an object of the present invention is to provide a paper feeding device having a simple structure.

[0007]

According to another aspect of the present invention, there is provided a first gear provided on a shaft of one paper feed roller for taking out a paper from one of the paper feed trays and feeding the paper, and the other gear. A second gear provided on the shaft of the other paper feed roller for taking out and feeding the paper from the paper feed tray, a motor capable of forward and reverse rotation drive, and located between the first and second gears, An arm that rotates around the motor shaft of the motor in conjunction with the rotation of the motor, and a transmission gear that is attached to the arm and that transmits the drive of the motor, and when the motor shaft rotates forward, When the arm rotates in the direction of the first gear, the transmission gear meshes with the first gear, and the motor shaft rotates in the reverse direction, the arm rotates in the direction of the second gear. The transmission gear meshes with the second gear.

According to the first aspect of the invention, when paper is fed from one of the paper feed trays, the motor shaft is normally rotated to drive one of the paper feed rollers and feed from the other paper feed tray. In this case, by the configuration in which the motor shaft is rotated in the reverse direction to drive the other paper feed roller, one motor can feed paper from two paper feed trays, and the number of parts can be reduced. Further, only the arm that rotates around the shaft of the motor and the transmission gear that is attached to the arm are provided, and there is no need to separately provide a one-way clutch or the like as in the conventional case, and the configuration is simple.

According to a second aspect of the present invention, in the first aspect of the present invention, the arm is provided with a biasing means for biasing the arm to an intermediate position, and when the rotational drive of the motor is stopped, the arm is The urging means moves the transmission gear to an intermediate position away from the meshing position of the first and second gears.

According to the second aspect of the invention, the urging means moves the arm to the intermediate position, so that the driving of the sheet feeding is canceled when the feeding by the sheet feeding roller is not necessary. The load on the paper is stable, and the paper can be conveyed stably.

That is, after the paper is fed by the paper feed roller,
For example, it is conveyed by a conveyance roller, a registration roller, or the like (hereinafter, simply referred to as “registration roller”). At this time, if the driving of the paper feeding roller is not released, the conveyance speed between the registration roller and the paper feeding roller is changed. Since it is difficult to make them coincide with each other, there arises inconveniences such as a load on the paper and a jam. However, according to the second aspect of the present invention, when it is not necessary to convey the sheet by the sheet feeding roller (when the sheet is conveyed by the registration roller or the like).
When the driving of the paper feed is canceled, the paper feed roller rotates with respect to the paper at the conveyance speed by the registration rollers and the like, and thus the paper is not burdened.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described in (3) above, an idler gear that meshes with one of the first and second gears is provided, and when the arm rotates, the idler gear meshes with the transmission gear.

According to the third aspect of the present invention, by providing the idler gear, the two paper feed rollers can be fed in the same direction. For example, the paper feed trays are stacked in two stages. Therefore, the device becomes compact.

The invention according to a fourth aspect is the first to the third aspects.
In the invention according to any one of items 1 to 3,
It is characterized in that it is attached to the main body by a fixing member, and an elastic member is interposed between the main body and the fixing member.

According to the fourth aspect of the invention, by interposing the elastic member, it is possible to prevent the vibration of the motor from propagating to the main body and reduce the noise due to the vibration of the motor. Further, by preventing the vibration of the motor from propagating, the main body is less likely to vibrate, so that the deterioration of the image due to the vibration is prevented.

[0016]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
A first embodiment will be described. FIG. 1 schematically shows a printer to which the present invention is applied. The printer 1 includes an image forming unit 2 that forms an image on a sheet and a sheet feeding device 3 that feeds the sheet. A photoconductor 4 rotating in the direction of arrow a is arranged in the image forming unit 2. The surface of the photoconductor 4 is uniformly charged by a charging device 5, and the writing device 7 performs optical writing (indicated by a dashed line in the figure). (See) to carry an electrostatic latent image. The electrostatic latent image on the photoconductor 4 is developed as a toner image by the developing device 9.

The sheet is conveyed by a registration roller 11 arranged below the photoconductor 4 so as to match the toner image on the photoconductor 4, and the toner image on the photoconductor 4 is transferred to the transfer device 13.
Is transferred to paper by. The toner image transferred onto the sheet is fixed by the fixing device 15 and is ejected by the sheet ejection roller 18 (see a chain double-dashed line in FIG. 1). Incidentally, reference numeral 17 in the drawing denotes a cleaning device, which is a photosensitive member 4 after transfer.
The toner remaining on the toner is removed.

The paper feeding device 3 is located below the registration rollers 11, and has a first paper feeding tray (one paper feeding tray) 19 located inside the main body and a second paper feeding tray located outside the main body. A paper tray (the other paper feeding tray) 21 and a drive unit (see FIGS. 2 and 3) 23 are arranged.

The first paper feed tray 19 is the first paper feed tray 1.
It has a first paper feed roller (one of the paper feed rollers) 25 for feeding the paper No. 9 and a separation pad 27 for pressing the first paper feed roller 25 and separating the paper one by one.

As shown in FIG. 3, the first paper feed roller 25
Is fixed to the first roller shaft 29, and the first gear 31 is fixed to the first roller shaft 29. The first paper feed roller 25 is rotated in the direction of arrow b in FIG. 1 by the first gear 31 to which the driving force is transmitted from the transmission gear 57 described later. By this rotation, the first paper feed roller 25 takes out the paper from the first paper feed tray 19 and feeds it toward the registration roller 11.

The second paper feed tray 21 has a second paper feed roller (the other paper feed roller) 33 and a separation pad 35, like the first paper feed tray 19 described above. The paper feed roller 33 is fixed to a second roller shaft 35 to which a second gear 37 is fixed. The second paper feed roller 33 rotates in the direction of arrow c in FIG. 1 by the second gear 37 to which the driving force is transmitted from the transmission gear 57, takes out the paper from the second paper feed tray 21 and directs it toward the registration roller 11. To feed.

The drive unit 23 includes a motor 39 and an arm 40.
The motor 39 is fixed to the bracket 45 by screws (fixing members) 47. Bracket 4
5 is fixed to the main body 41 by screws (fixing members) 43, and an elastic member 49 is interposed between the screws 43 and the main body 41 as shown in FIG. As the fixing member, in addition to the screws 43 and 47, for example, a bolt and a nut may be combined, or a pipette or the like may be used.

The elastic member 49 is made of a rubber material and absorbs vibration of the motor 39. By interposing the elastic member 49, it is possible to prevent the vibration of the motor 39 from propagating to the main body and reduce noise due to the vibration of the motor 39.
Further, by preventing the vibration of the motor 39 from propagating,
Since the main body 41 is less likely to vibrate, deterioration of an image due to vibration is prevented. In the present embodiment, the elastic member 49
However, the present invention is not limited to this, and any member having elasticity may be used.

The motor 39 can be driven to rotate forward and backward, and a drive gear 53 that rotates integrally with the motor shaft 51 is attached to the motor shaft 51 of the motor 39. The arm 40 is located between the first gear 31 and the second gear 37 (located at an intermediate position), and is rotatably supported around the motor shaft 51. That is, as shown in FIG. 2, when the drive gear 53 rotates forward (when it rotates in the direction of arrow g),
The arm 40 rotates in the direction of arrow e, and the drive gear 53
When rotating in the reverse direction (when rotating in the direction of arrow f), the arm 40 rotates in the direction of arrow d.

A transmission shaft 55 is fixed to the arm 40, and a transmission gear 57 is rotatably attached to the transmission shaft 55 with respect to the transmission shaft 55. The transmission gear 57 is
It constantly meshes with the drive gear 53 of the motor 39. The transmission gear 57 meshes with one of the first and second gears 31 and 37 by the rotation of the arm 40 described above, and transmits the drive of the motor 39 to the first and second gears 31 and 37.

Therefore, when the transmission gear 57 meshes with the first gear 31, it transmits the driving force of the motor 39 to the first gear 31, and when it meshes with the second gear 37, it drives the motor 39. The force is transmitted to the second gear 37. As shown in FIG. 3, the first and second gears 31, 37 and the transmission gear 57 are respectively provided with pitch circles 31a, 37a, 57a integrally with the gears 31, 37, 57, respectively. It ensures that the pitch between gears is maintained.

A spring (biasing means) 59 is provided between the tip 40a of the arm 40 and one end 45a of the bracket 45. The spring 59 connects the arm 40 to one end of the bracket 45. It is biased in the direction of 45a.

Next, the operation of the first embodiment will be described based on the above configuration. When paper is fed from the first paper feed tray 19, the motor 39 is driven and the drive gear 53 is rotated in the direction of arrow g in FIG. 2 (normal rotation). Drive gear 53
When the arm rotates forward, the arm 40 rotates in the direction of arrow e in FIG. 2, and the transmission gear 57 of the arm 40 meshes with the first gear 31. As a result, the first paper feed roller 25 is moved to the arrow b in FIG.
The sheet is rotated in the direction to take out the sheet from the first sheet feed tray 19 and feed it toward the registration roller 11.

The sheet hits the registration roller 11 and
When a predetermined slack is made, the motor 39 stops. When the motor 39 stops, the force for rotating the arm 40 in the direction of arrow g in FIG. 2 disappears. Return to. As a result, the drive transmitted to the first paper feed roller 33 is released, and the first paper feed roller 33 follows the paper conveyed by the registration roller 11 to the photoconductor 4 at the conveyance speed by the registration roller 11. Turn around.

When paper is fed from the second paper feed tray 21,
The drive gear 53 is rotated in the direction of arrow f in FIG. 2 (reverse rotation), the arm 40 is rotated in the direction of arrow d, and the transmission gear 57 and the second gear 37 are meshed with each other, whereby the second feed is performed. The paper roller 33 rotates in the direction of arrow c in FIG. 1, takes out the paper from the second paper feed tray 21, and feeds it toward the registration roller 11. Then, when the sheet hits the registration roller 11 and makes a predetermined slack, the motor 39 stops and the arm 40 is returned to the intermediate position (position away from the second gear) shown in FIG. 2 by the urging force of the spring 57. Then, the second paper feed roller 33 rotates together with the paper. In this way, one motor 39 can feed paper from the two paper feed trays 19 and 21, and the number of parts can be reduced.

The spring 59 causes the arm 40 to move to the first position.
By moving to an intermediate position away from the second gears 31 and 37, and when conveyance by the paper feed roller is unnecessary,
Since the driving of the paper feed is released, it does not burden the paper,
Paper conveyance is stable.

That is, the paper is the first or second paper feed roller 2
After being fed by the registration rollers 11, the sheet is conveyed by the registration rollers 11, and if the driving of the first or second sheet feeding rollers 25, 33 is not released at this time, the registration rollers 11 and the first or second sheet feeding are performed. Since it is difficult to match the conveyance speeds of the rollers 25 and 33, the paper is burdened,
Inconvenience such as occurrence of jam occurs. However, when the conveyance by the first or second paper feed rollers 25, 33 is not necessary (when the paper is conveyed by the registration rollers 11), the drive is released, so that the first or second paper feed rollers are released. The sheets 25 and 33 rotate together at the conveyance speed of the registration rollers 11, so that the sheets are not burdened.

Further, only the arm 40 that rotates around the motor shaft 51 of the motor 39 and the transmission gear 57 that is attached to the arm 40 are provided, and it is necessary to separately provide a one-way clutch or the like as in the conventional case. No, the configuration is simple.

Next, the second embodiment will be described. In the description, the same parts as those described above are designated by the same reference numerals and the description thereof will be omitted.

FIG. 5 shows a drive unit 23 according to the second embodiment.
Indicates. In the second embodiment, the idler gear 61 that meshes with the second gear 37 is provided, and the transmission gear 57 meshes with the idler gear 61 when the arm 40 rotates in the direction of arrow d. Different from the embodiment.

By providing the idler gear 61, the paper feeding directions of the first and second paper feeding rollers 25 and 33 can be made the same. Therefore, in the second embodiment, in the paper feeding device 3, as shown in FIG.
The device can be made compact because it is possible to have a structure in which 9, 21 are stacked in two stages.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the elastic member 49 may be replaced by the motor 3
It may be provided on a screw 47 for fixing the bracket 9 and the bracket 45. In addition, in the second embodiment, the idler gear 61
May be meshed with the first gear 31.

Furthermore, although the present invention is applied to a printer, the present invention is not limited to this. For example, the present invention is applied to a copying machine, a facsimile, or a multi-function machine in which any of these is combined with a printer. To get

[0039]

According to the first aspect of the present invention, the paper can be fed from the two paper feed trays by one motor, and the number of parts can be reduced. Further, the structure is simple because only the arm that rotates around the shaft of the motor and the transmission gear that is attached to the arm are provided.

According to the second aspect of the invention, the urging means moves the arm to the intermediate position away from the first and second gears to drive the sheet feeding when the feeding by the sheet feeding roller is not necessary. Is released, the paper is not burdened and the transportation of the paper is stable.

According to the third aspect of the present invention, by providing the idler gear, the two paper feed rollers can be fed in the same direction, and the size of the apparatus can be reduced.

According to the fourth aspect of the invention, by interposing the elastic member, it is possible to prevent the vibration of the motor from propagating to the main body and reduce the noise due to the vibration of the motor.
Prevents image deterioration due to vibration.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a printer to which the present invention is applied.

FIG. 2 is a configuration diagram schematically showing a drive unit.

FIG. 3 is a cross-sectional view showing the vicinity of a drive unit.

FIG. 4 is an enlarged cross-sectional view showing the vicinity of a screw fixing a bracket and a main body.

FIG. 5 is a configuration diagram schematically showing a drive unit according to a second embodiment.

FIG. 6 is a configuration diagram schematically showing a paper feeding device according to a second embodiment.

[Explanation of symbols]

3 Paper feeder 19 First paper feed tray (one paper feed tray) 21 Second paper feed tray (other paper feed tray) 25 First Paper Feed Roller (One Paper Feed Roller) 29 First roller shaft 31 First Gear 33 Second paper feed roller (other paper feed roller) 35 Second roller shaft 37 Second Gear 39 motor 40 arms 43, 47 screw (fixing member) 49 Elastic member 51 motor shaft 57 transmission gear 59 spring (biasing means) 61 idler gear

Claims (4)

[Claims] 1. A first gear provided on the shaft of one paper feed roller for taking out and feeding paper from one paper feed tray, and the other for taking out and feeding paper from the other paper feed tray. A second gear provided on the shaft of the sheet feeding roller, a motor capable of forward and reverse rotation driving, and a motor shaft of the motor which is located between the first and second gears and which is interlocked with the rotation of the motor. An arm that rotates about the axis and a transmission gear that is attached to the arm and that transmits the drive of the motor. When the motor shaft rotates forward, the arm rotates in the direction of the first gear. Then, when the transmission gear meshes with the first gear and the motor shaft rotates in the reverse direction, the transmission gear rotates in the direction of the second gear and the transmission gear meshes with the second gear. And a paper feeder. 2. An urging means for urging the arm to an intermediate position is provided, and when the rotational drive of the motor is stopped, the arm is urged by the urging means to cause the transmission gear and the first and second transmission gears to move. The sheet feeding device according to claim 1, wherein the sheet feeding device moves to an intermediate position away from a meshing position with a gear. 3. An idler gear that meshes with any one of the first and second gears, and when the arm rotates, the idler gear meshes with the transmission gear. 2. The paper feeding device according to item 2. 4. The motor according to claim 1, wherein the motor is attached to the main body by a fixing member, and an elastic member is interposed between the main body and the fixing member. The paper feeder described in.