JP2002187630A - Paper feeding unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding unit miniaturized by reducing the number of components. SOLUTION: A stepping motor 52 is built in a manual tray 50 and rotates a paper feeding roller 84. The paper feeding roller 84 is fixed on a rotation shaft 60 through a one way clutch 86. A middle plate press down cam 80 is also fixed on the rotation shaft 60 through a one way clutch 82 to keep a middle plate 72 away from the paper feeding roller 84.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and a laser beam printer, and a paper feeding unit in an apparatus using various sheets.

[0002]

2. Description of the Related Art As an output device of a computer or a work station, an ink jet type image forming apparatus for forming an image on a recording medium by discharging ink, or an electronic apparatus for forming an image on a recording medium using a developer (toner) or the like. A photographic image forming apparatus is known. These image forming apparatuses are usually provided with a sheet feeding device that feeds a plurality of stacked sheet-shaped recording media one by one in a predetermined sheet feeding direction. The sheet feeding device is mounted on a main body of the image forming apparatus as a cassette tray, a manual tray, or the like.

In a sheet feeding apparatus, usually, a sheet feeding roller rotates while being in contact with an uppermost recording medium among a plurality of stacked recording media. The paper is fed in the paper feeding direction. The rotational force for rotating the paper feed roller is transmitted to the paper feed roller via a gear train from a motor incorporated in the main body of the image forming apparatus.

[0004] Further, the sheet feeder incorporates an intermediate plate on which a plurality of recording media are directly stacked. By pressing the middle plate loaded with recording media against the paper feed roller,
The recording medium comes into direct contact with the paper feed roller. By rotating the paper feed roller at a predetermined timing in this state,
As described above, the uppermost recording medium is fed in the paper feeding direction. In order to rotate the paper feed roller at a predetermined timing, the rotation of the paper feed roller is controlled using an electromagnetic clutch or a spring clutch provided in the paper feed device.

Further, a pressing member is arranged in the sheet feeding device in order to press the above-mentioned middle plate toward the sheet feeding roller. On the other hand, when a new recording medium is loaded on the middle plate, the middle plate is moved away from the paper feed roller against the pressing force of the pressing member.
Therefore, in order to control the timing of pressing the middle plate toward the paper feed roller or moving the middle plate away from the paper feed roller, a spring clutch or a solenoid that moves the pressing member is provided in the paper feed device.

[0006]

As described above, the conventional paper feeder is provided with an electromagnetic clutch, a spring clutch, a solenoid, and the like, so that a space for accommodating them is formed in the paper feeder. . Further, a space for arranging a bundle of cables (bundled wires) for sending a signal to an electric component such as an electromagnetic clutch and a space for laying out the bundled wires are also formed in the sheet feeding device. Therefore, there is a problem that the conventional sheet feeding device has a large number of components and is large.

Further, as described above, in the conventional paper feeder, the paper feed roller is rotated by the rotational force of the motor incorporated in the main body of the image forming apparatus. Therefore, since the paper feed roller is disposed at a position where the torque of the motor can be easily transmitted, the place where the paper feed device can be mounted is limited. For this reason, the image forming apparatus may become large instead of being downsized.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a sheet feeding unit capable of reducing the number of parts and making the unit smaller than before.

[0009]

According to a first aspect of the present invention, there is provided a sheet feeding unit comprising: (1) a loading member on which a plurality of recording media are loaded; and (2) a loading member loaded on the loading member. In order to feed a recording medium in a predetermined feeding direction, a predetermined first
A feed roller that is driven to rotate in a predetermined first rotation direction at a timing; (3) a biasing member that biases the stacking member toward the feed roller; and (4) a biasing force of the biasing member. A remote member for overcoming and moving the loading member away from the paper feed roller at a second timing different from the first timing; and (5) both the paper feed roller and the remote member at the first and second timings, respectively. And a driving source for driving.

Here, the drive source drives (6) the paper feed roller to rotate in the first rotational direction at the first timing by rotating forward, and to rotate the remote member by rotating in reverse. The motor may be driven at two timings to move the loading member away from the paper feed roller.

(7) The paper supply unit includes a rotating shaft connected to the motor and rotating. (8) The paper supply roller rotates so that the paper supply roller rotates only in the first rotation direction. And (9) the remote member transfers the loading member from the paper feed roller to the paper feed roller via a first one-way clutch that transmits the rotational force of the rotary shaft to the paper feed roller. The remote member may be fixed to the rotary shaft via a second one-way clutch that transmits the rotational force of the rotary shaft to the remote member so that the remote member is driven only in a remote direction.

(10) The remote member may be a cam that rotates only in the remote direction.

(11) The motor is a stepping motor for selectively performing forward rotation and reverse rotation.
(12) The paper feeding unit may include a drive gear fixed to the rotation shaft, and a transmission gear for transmitting a rotational force of the stepping motor to the drive gear.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a paper feeding unit according to the present invention will be described with reference to the drawings.

Referring to FIG. 1, an image forming apparatus to which an embodiment of a sheet feeding unit of the present invention is mounted will be described.

FIG. 1 is a schematic diagram showing a schematic configuration of a copying machine which is an example of an image forming apparatus to which an embodiment of a sheet feeding unit of the present invention is mounted.

On the top surface of the copying machine 10, an openable and closable original cover 12 is arranged. On the front side of the top surface, an operation panel display unit (not shown) for inputting the number of copies and the like is provided.
Is arranged. The copying machine 10 is provided with a universal cassette 16 (an example of a paper feeding unit according to the present invention) for accommodating a plurality of cut sheets, which can be freely inserted and removed from the front side of the main body of the copying machine 10.

On the right side wall of the copying machine 10, a manual tray 50 (an example of a paper feeding unit according to the present invention) capable of feeding small-sized recording paper such as a postcard is detachably mounted. . This manual feed tray 50 is described in FIG.
This will be described in detail with reference to FIGS. The left side wall of the copying machine 10 is provided with a discharge tray 20 on which recording paper on which an image is formed is stacked.

Under the original cover 12, an original table glass 26 on which an original 24 (thickly drawn) is placed is arranged. An original 24 is placed on the original platen glass 26 so that the image side thereof faces down, and the original 2 is
Hold down 4 to fix. The image recorded on the manuscript 24 is
A known optical system 28 including a light source lamp (not shown) and the like.
And light (broken line A) carrying the information of the image recorded on the original is obtained. This light is applied to the photosensitive drum 32 uniformly charged by the charger 30 to form an electrostatic latent image. This electrostatic latent image is developed with the developer (toner) supplied from the developing device 34 to form a developed image. On the other hand, a recording medium such as recording paper sent out from the universal cassette 16 is fed in the direction of arrow B, and the developed image is transferred to the recording medium by the transfer unit 36. When the recording medium is sent out from the manual feed tray 50, the recording medium is fed in the direction of arrow C.

The recording medium onto which the developed image has been transferred is transported by the transporter 3
By 8, it is conveyed to the fixing device 40. The fixing device 40 is provided with a heating roller 42 and a pressure roller 44. The recording medium is conveyed while being nipped between the two rollers 42, 44, and the developed image is fixed on the recording medium. The recording medium on which the developed image has been fixed in this manner is discharged and stacked on the discharge tray 20. After the transfer, the photosensitive drum 32
The remaining toner is scraped off by the cleaning device 46. As described above, the recording medium can be fed from the manual feed tray 50, and the procedure for forming an image on the recording medium fed from the manual feed tray 50 is the same as described above.

The above-mentioned manual tray 50 will be described with reference to FIGS.

FIG. 2 is a front view showing the manual feed tray. FIG. 3 is a side view showing the manual feed tray during the sheet feeding operation. FIG. 4 is a side view showing the manual feed tray in a state where a recording medium can be stacked. FIG. 5 is a flowchart showing a procedure in which a paper feed roller, a cam, and the like move.

The manual feed tray 50 includes a housing (not shown) and a stepping motor 52 (an example of a driving source according to the present invention) fixed to the housing. Further, two reduction gears 56 and 58 are rotatably fixed to the side wall 54 of the housing by meshing with each other. The reduction gear 56 meshes with a gear 52 a fixed to the rotation shaft of the stepping motor 52.

The manual tray 50 has a side wall 55 facing the side wall 54. These two side walls 54,
55 has a rotating shaft 6 extending in a direction orthogonal to the arrow C direction.
0 is rotatably fixed via bearings 62,62. The rotating shaft 60 protrudes from the side wall 54, and a driving gear 64 is fixed to the protruding portion. The drive gear 64 meshes with the reduction gear 58. Therefore, when the stepping motor 52 rotates, the rotational force is transmitted to the gear 52a, the reduction gears 56 and 58, and the drive gear 64 to rotate the rotation shaft 60.

A loading plate 68 on which a plurality of recording media 66 are loaded is disposed below the rotating shaft 60. On the downstream side of the loading plate 68 in the direction of arrow C, an intermediate plate 72 (which is an example of a loading member according to the present invention) that rotates by a predetermined angle in the direction of arrow D about the rotation shaft 70 is disposed. . Middle plate 7
2 is located almost directly below the rotating shaft 60, and the loading plate 68
Of the recording medium 66 stacked in the direction indicated by the arrow C is stacked on the middle plate 72. A coil spring 7 is provided under the middle plate 72.
4 (which is an example of an urging member according to the present invention) is disposed.
Energize towards.

A flag 76 extending downward is formed integrally with the middle plate 72 at the end of the middle plate 72 (upstream portion in the direction of arrow C). When the intermediate plate 72 is rotated downward to be ready for loading the recording medium, as shown in FIG.
Flag 76 is a micro sensor (or photo sensor)
It is detected at 78.

A portion of the rotary shaft 60 opposite to the drive gear 64 with the side wall 54 interposed therebetween is provided with a coil spring 74.
The intermediate plate pressing cam 80 (which is an example of a remote member according to the present invention) which presses down the intermediate plate 72 by overcoming the urging force of the above is fixed via a one-way clutch 82 (which is an example of a second one-way clutch according to the present invention). Have been. The middle plate 72 moves away from the paper feed roller 84 by being pushed down.

The one-way clutch 82 moves the middle plate pressing cam 80 only in the direction in which the middle plate 72 is moved away from the sheet feeding roller 84.
The rotation force of the rotating shaft 60 is applied so that the
Transmit to 0. Here, only when the stepping motor 52 rotates (reverse rotation) in the direction of the arrow E, the intermediate plate pressing cam 80 rotates in the direction of the arrow F. Conversely, when the stepping motor 52 rotates in the direction of arrow G (forward rotation), the middle plate pressing cam 80 does not rotate. The middle plate 72 is formed integrally with a middle plate cam guide 81 for guiding the middle plate pressing cam 80 in the direction of arrow F.

Of the two ends in the longitudinal direction of the rotating shaft 60, an end opposite to the end to which the middle plate pressing cam 80 is fixed is provided with:
The paper feed roller 84 is fixed via a one-way clutch 86 (an example of a first one-way clutch according to the present invention). The one-way clutch 86 is connected to the paper feed roller 8.
The rotation force of the rotation shaft 60 is transmitted to the sheet feeding roller 84 so that the rotation of the rotation shaft 4 is only in the direction of the arrow H (an example of the first rotation direction in the present invention). Here, the stepping motor 5
The paper feed roller 84 rotates in the direction of the arrow H only when 2 rotates in the direction of the arrow G. Conversely, when the stepping motor 52 rotates in the direction of arrow F, the paper feed roller 84 does not rotate.

A separation pad 88 for sending out a plurality of recording media stacked on the middle plate 72 one by one in the direction of arrow C is arranged on the front end side (upstream side in the direction of arrow C) of the middle plate 72. . The separation pad 88 is pressed against the paper feed roller 84 by a spring 90.

The operation of the above-described stepping motor 52, paper feed roller 84, middle plate pressing cam 80, and the like will be described.

When a copy start key (not shown) of the copying machine 10 is pressed, a flow shown in FIG. 5 is started. Here, before the copy start key is pressed, the middle plate pressing cam 80 pushes down the middle plate 72 as shown in FIG. Therefore, in order to feed the recording medium 66 loaded on the middle plate 72, the stepping motor 52 is rotated at a low speed by a predetermined angle in the direction of arrow E (S501). By this rotation, the middle plate pressing cam 80 rotates at a low speed of about 90 ° (S502). Due to this rotation, the middle plate 72 is pushed up at a low speed by the urging force of the coil spring 74, and the recording medium 66 loaded on the middle plate 72 comes into contact with the paper feed roller 84 as shown in FIG. 3. As a result, preparation for sheet feeding is completed. The middle plate pressing cam 80 is lowered by its own weight, and as shown in FIG. 3, comes into contact with a portion of the middle plate 72 that is outside the paper passing area and stops.

After the middle plate pressing cam 80 rotates about 90 °,
The stepping motor 52 starts rotating in the direction of arrow G (S503). At this timing (an example of the first timing according to the present invention), the paper feed roller 84 rotates in the direction of the arrow H. As a result, the uppermost recording medium among the plurality of recording media 66 stacked on the middle plate 72 is sent out in the paper feeding direction (the direction of arrow C), and copying is started (S50).
4). Thereafter, it is determined whether or not the copy is completed (S
505) When the copying is completed, the paper feed roller 84 is stopped (S506).

After the feed roller 84 stops, the stepping motor 52 starts rotating in the direction of arrow E (S50).
7). At this timing (an example of the second timing according to the present invention), the middle plate pressing cam 80 rotates in the direction of arrow F. By this rotation, the middle plate 72 is pushed down, and it is determined whether or not the flag 76 has turned on the microsensor 78 (S508). When the microsensor 78 is turned on, as shown in FIG. 4, the tip of the middle plate pressing cam 80 is fitted into the concave portion 72a of the middle plate 72, and the middle plate 72 is moved away from the paper feed roller 84. Have been. In this state, the stepping motor 52 stops (S509), and the copying operation ends completely. Since the middle plate 72 is separated from the sheet feeding roller 84, a new recording medium can be easily loaded on the middle plate 72.

As described above, the manual feed tray 50 incorporates the stepping motor 52, and also incorporates the paper feed roller 84 and the middle plate pressing cam 80 which are rotated by the stepping motor 52. Accordingly, unlike the related art, since the driving force of the driving motor disposed in the main body of the copying machine 10 is not used, a component for transmitting the driving force to the paper feed roller 84 or the like becomes unnecessary. As a result, the manual feed tray 50
Not only can be reduced in size, but also the installation location of the manual feed tray 50 can be selected relatively freely, and the degree of freedom in designing the copying machine 10 can be increased.

[0036]

As described above, the sheet feeding unit of the present invention can be made smaller by five components including a stacking member, a sheet feeding roller, an urging member, a remote member, and a driving source. Further, since the remote member moves the loading member away from the sheet feeding roller, it is easy to load the recording medium on the loading member. further,
Since the paper feeding unit of the present invention has a driving source and does not require another driving source, a place (arrangement position) where this paper feeding unit is mounted can be selected relatively freely. Therefore, in the image forming apparatus to which the sheet feeding unit of the present invention is attached, the degree of freedom in design is increased.

Here, the drive source rotates the paper feed roller in the first rotation direction at the first timing by rotating forward, and rotates the remote member at the second timing by rotating backward. When the motor is driven to move the loading member away from the paper feed roller,
Since the driving source is a motor, the size of the sheet feeding unit can be further reduced.

The paper feed unit further includes a rotating shaft connected to the motor and rotating, and the paper feeding roller is provided with a rotating force of the rotating shaft such that the paper feeding roller rotates only in the first rotation direction. And the remote member is driven by the remote member only in a remote direction that moves the loading member away from the paper feed roller through a first one-way clutch that transmits the load member to the paper feed roller. In the case where the feed roller and the remote member are fixed to one rotary shaft, the feed roller and the remote member are fixed to the rotary shaft via a second one-way clutch that transmits the rotational force of the rotary shaft to the remote member. As a result, the size of the paper feed roller can be further reduced.

Further, when the remote member is a cam that rotates only in the remote direction, a remote member having a simple structure can be obtained.

Further, the motor is a stepping motor for selectively performing forward rotation and reverse rotation, and a driving gear fixed to the rotating shaft, and a transmission gear for transmitting the rotating force of the stepping motor to the driving gear. Is provided in the sheet feeding unit, the driving force of the motor can be reliably transmitted to the sheet feeding roller and the remote member (cam) with a small number of parts.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a schematic configuration of a copying machine as an example of an image forming apparatus to which an embodiment of a sheet feeding unit according to the present invention is mounted.

FIG. 2 is a front view showing a manual feed tray.

FIG. 3 is a side view illustrating the manual feed tray during a sheet feeding operation.

FIG. 4 is a side view showing the manual feed tray in a state where a recording medium can be stacked;

FIG. 5 is a flowchart showing a procedure in which a paper feed roller, a cam, and the like move.

[Explanation of symbols]

 Reference Signs List 50 manual feed tray 52 stepping motor 60 rotation shaft 72 middle plate 74 coil spring 80 middle plate pressing cam 82, 86 one-way clutch 84 paper feed roller

Claims (5)

[Claims] 1. A loading member on which a plurality of recording media are loaded, and a predetermined first rotation at a predetermined first timing for feeding the recording media loaded on the loading member in a predetermined feeding direction. A paper feed roller that is driven to rotate in the direction, an urging member that urges the loading member toward the paper feeding roller, and the loading member that overcomes the urging force of the urging member and that the first timing A sheet feeding unit comprising: a remote member that moves away from the sheet feeding roller at a different second timing; and a drive source that drives both the sheet feeding roller and the remote member at the first and second timings, respectively. . 2. The driving source drives the paper feed roller to rotate in the first rotation direction at the first timing by rotating forward, and drives the remote member at the second timing by rotating backward. The paper feeding unit according to claim 1, wherein the motor is a motor that moves the loading member away from the paper feeding roller. 3. The apparatus according to claim 1, further comprising a rotating shaft connected to the motor and rotating, wherein the sheet feeding roller applies the rotational force of the rotating shaft so that the sheet feeding roller rotates only in the first rotation direction. 1st transmitted to roller
The remote member is fixed to the rotary shaft via a one-way clutch, and the remote member controls the rotational force of the rotary shaft so that the remote member is driven only in a remote direction that moves the loading member away from the paper feed roller. The paper feed unit according to claim 2, wherein the paper feed unit is fixed to the rotating shaft via a second one-way clutch that transmits the remote member. 4. The paper feeding unit according to claim 3, wherein the remote member is a cam that rotates only in the remote direction. 5. The motor according to claim 1, wherein the motor is a stepping motor that selectively performs normal rotation and reverse rotation, a driving gear fixed to the rotation shaft, and a transmission gear that transmits a torque of the stepping motor to the driving gear. The sheet feeding unit according to claim 3, further comprising: