JP2836268B2 - Paper feeder of image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder in an image forming apparatus such as an electronic copier or a printer, and more particularly, to a paper feeder.
The present invention relates to a sheet feeding device in which a pickup roller is supported via a swing mechanism and is pressed against a sheet only during sheet feeding.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electronic copier or a laser printer, a plurality of paper storage means such as a paper supply tray or a cassette is mounted on a paper supply unit, and the paper storage apparatus is mounted on the paper storage unit. By storing sheets of different sizes, a means is used to select a sheet of an appropriate size according to information such as the size of the document and the enlargement / reduction ratio and to make a copy. In the image forming apparatus, a device in which a paper storage device is mounted from the side of the device is generally used, but recently, as called a front loading type, a paper storage device is moved in and out from the front side of the device. Those that are configured to obtain are often used.

A conventional front-loading type image forming apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-231324.
An example as shown in Japanese Patent Application Laid-Open Publication No. H10-260, is known. In the conventional electronic copying machine, a plurality of paper feeders are arranged in multiple stages in a paper feed unit of the apparatus main body, and a paper storage device such as a paper feed tray is provided so as to be attachable to each paper feed device. Figure 8
It is configured as shown in FIG. The example shown in FIG. 8 shows a case where an electronic copying machine is used as the image forming apparatus. The copying machine 1 includes, for example, an upper device 2 provided with a mechanism for creating a xerographic toner image. And a lower device 3 mainly equipped with a paper feeding device.

In the electronic copying machine 1, an upper device 2 includes an optical device 10 for scanning an image of a document corresponding to a platen 4 disposed on the upper portion, as in a general copying machine. Drum 11 for forming toner image, and developing device 1 arranged around drum 11
2. The transfer device 13 and the cleaning device are arranged. Further, a conveying belt device for conveying the sheet on which the toner image is transferred from the photosensitive drum 11 toward the fixing device 17 is provided, the sheet is guided to the fixing device, and the fixing device 17 performs a fixing operation. Copy tray 1
8 to be discharged.

The upper device 2 is provided with a single paper storage device 5 so as to be capable of feeding paper. The lower device 3 is provided with a plurality of paper storage devices 6 such as a plurality of paper trays. ~
8 are arranged so that sheets of any size can be fed from each sheet storage device. The intermediate tray 9 disposed below the sheet storage device 7 is used for copying the back side of the one created as a one-sided copy through the fixing device 17, and is used for returning. A one-sided copy is introduced via path 19. Further, the lowermost sheet storage device 8 is configured as a large capacity tray. In order to feed paper from the paper storage device, paper supply devices 15 are arranged corresponding to the paper storage device. Each of the paper feeding devices 15 uses a paper feeding unit having the same configuration except for a paper feeding unit from an intermediate tray, and a paper feed roller device provided in each of the paper feeding devices 15. The sheet is carried out from the sheet storage device using the sheet feeding device, and the sheet is conveyed toward the image recording unit by the conveying device 14 via the sheet path 16.

[0006] The paper feeders arranged corresponding to the respective paper storage devices are provided with roller members as shown in FIG. In the paper feeding device shown in FIG. 9, a clutch member 41 for driving the driving device 40 and the driving shaft 30 is provided on the main body frame 24. Further, in a state of crossing the frame 24, a shaft member for each roller device is arranged, a feed roller 22 is arranged for the drive shaft 30, and via the side frames 25 and 26 supported by the drive shaft, The pickup roller 21 is provided to be swingable.

[0007] The pickup roller and the feed roller are configured to be interlocked via a drive gear device 23. By connecting a clutch 41, a paper feed device is connected via a drive device 40. , And the sheet feeding operation can be performed. The pickup roller 21 is swingably supported via a protruding member 28 provided on the side frame 26, and is used only when the sheet is carried out of the sheet storage device.
1 is pressed against the paper and driven to perform the operation of feeding paper from the paper storage device.

[0008]

[0009]

In the conventional image forming apparatus constructed as described above, if the detection information is output during the operation in which the sheet feeding device performs the sheet feeding operation. , Vibration of each driving member and operating member,
It may affect the detection means. For example, if the detection of the swing position of the pickup roller coincides with the timing at which the pickup roller presses the sheet, there is a problem that detection information cannot be obtained accurately due to the vibration of the operation of the pickup roller.

[0010]

In the paper storage device, a lifting mechanism is provided for the bottom plate that supports the paper, and an operation of lifting the bottom plate is performed based on information from a paper height detection device. However, even if the push-up device is driven for a certain period of time, the rising speed of the sheet is not constant, and the control of the sheet height becomes unstable. Further, when detecting the height of the paper while the paper is being lifted, the pickup roller moved toward the paper may detect a state before being stabilized by being pressed by the paper, A problem arises in that detection information cannot be obtained accurately.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem of the conventional image forming apparatus, and inhibit the detecting operation on the sheet from the state where the pickup roller is held until the sheet is pressed against the sheet. It is another object of the present invention to provide an apparatus for detecting the position of the pickup roller after the pickup roller has been stabilized on the sheet.

[0013]

The present invention relates to a paper feeder for an image forming apparatus, and more particularly, to a pickup roller for taking out a sheet from a sheet storage device, a rocking mechanism for rocking the pickup roller, and a rocking mechanism. Holding means for holding the pickup roller in a state of being separated from the sheet via a mechanism, and a state in which the pickup roller is held by the holding means via the swing mechanism when feeding the sheet from the sheet storage device Moving means for moving the pick-up roller to a state pressed against a sheet, and a sensor for detecting a rocking position of the rocking mechanism, while the moving means moves the pick-up roller. Is characterized in that the detection timing is set so that the detection operation by the sensor is not performed.

[0014]

[0015]

As described above, in the present invention, the detecting operation on the sheet is prohibited while the pickup roller is rocked until it is pressed by the sheet from the state where the pickup roller is not in contact with the sheet. Since the position of the pickup roller is detected after the pickup roller has become stable, the malfunction of the sensor due to the fluttering of the swinging mechanism can be avoided, and the stable paper detection can be performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper feeder of an image forming apparatus according to the present invention will be described with reference to the illustrated example. The sheet feeding device shown in FIGS. 1 to 3 is provided for an image forming apparatus as shown in FIG. 7, and is used for a large number of sheet storage devices mounted in multiple stages on a frame of the image forming device. Each is arranged,
The paper is fed from the paper storage device. 1 has a roller unit 20 disposed on a main body frame 24. The roller unit 20 includes a pickup roller 21 and a feed roller 22, and a drive gear device as an interlocking means of both rollers. Is provided.

In the paper feeding device 15, a driving device 40 is disposed on one side of the frame, and the driving device 40 is used to drive the transport roller device 48 and the rollers provided in the roller unit. Like that. In order to drive the roller unit 20, an output gear 42 and an intermediate gear 43 are arranged via a clutch 41. Then, the input gear 31 arranged at the end of the drive shaft 30 of the roller unit 20 meshes with the intermediate gear 43 to drive the pickup roller and the feed roller.

As shown in detail in FIG. 2, the structure of the roller unit 20 is such that side frames 25 and 26 are arranged on both sides of a support frame 27, and the axes of a pickup roller 21 and a feed roller 22 are mounted on the frames. Let them support you. A drive gear device 23 is arranged between the two roller members. An end of the drive shaft 30 that supports the feed roller 22 protrudes from the side frame 25,
The input gear 31 is arranged as described above. Further, an arm member 28 is disposed on a side portion of the other side frame 26, and the arm member 28 is engaged with an operating member of the swing device 50,
The roller unit is caused to swing via the drive shaft 30. In addition to the above configuration, a predetermined position of the frame 27 is provided with an actuator 29 corresponding to the sheet height detection sensor.
And the position of the sheet accommodated in the sheet accommodating device is detected by detecting the height of the actuator.

When the roller unit 20 configured as described above is mounted on the paper feeding device 15,
Positioning is performed by inserting one bearing member 33 into the concave portion 36 provided on the shaft 4, and the bearing member 34 arranged on the other side of the shaft 30 is supported by positioning means (not shown). Then, the input gear 31 provided at the end of the drive shaft 30 is meshed with the intermediate gear 43 to transmit the driving force to the rollers of the roller unit.

As described above, the pickup roller 21
And a roller unit 20 including a feed roller 22,
In the present embodiment, inspection and replacement of these rollers can be easily performed by providing the paper feeding device 15 detachably with respect to the main body frame. Further, it is not necessary to attach a roller member or the like at the time of manufacturing the image forming apparatus, and the manufacturing process of the sheet feeding apparatus can be simplified.

The paper feeding device 15 incorporating the roller unit 20 will be further described. As described above, the paper height sensor 4 corresponding to the actuator 29 provided on the roller unit is provided on the frame 24 of the paper feeding device 15.
5 and a no-paper sensor 46 are arranged to detect the state of the paper in the paper storage device. In addition, a swing device 50 is disposed with respect to the arm member 28 arranged on the side of the roller unit 20, and the roller unit 20 is connected to the shaft 30 via a drive arm member 52 of the swing device 50.
It swings around the center.

As shown in FIG. 3, the oscillating device 50 is disposed on the side of the side frame 26 of the roller unit 20. 52 are engaged.
Further, in order to swing the arm 52, a solenoid 51 and a spring 54 are arranged, and the arm 52 is swung via a shaft 53.

For example, when the paper feeding operation is not performed,
Since the solenoid 51 is turned off, the swing device 5
The arm 52 is lifted by the zero spring 54, and the pickup roller 21 of the roller unit 20 is kept separated from the sheet via the shaft 30. Also,
When feeding the paper, turn on the solenoid 51,
The arm 52 is lowered, and the roller 21 is driven to send out the sheet while pressing the pickup roller 21 against the sheet by the weight of the roller unit and the action of the spring 55. The time during which the solenoid is energized is the time until the leading end of the sheet is nipped by the transport roller device disposed downstream of the separating device,
Alternatively, the setting is made only for a very short time until the leading end of the sheet passes through the separating portion and advances slightly. Further, the actuator 29 disposed at the leading end of the frame of the roller unit is located at a position detected by the sheet height sensor 45. And the roller unit 20
In a state where is lowered, the position of the actuator 29 is detected by the sensor 45, and based on the detection information,
A mechanism for controlling the height of the sheet corresponding to the sheet storage device is operated so that the position where the pickup roller contacts the sheet can be constantly adjusted.

(Paper Height Control Apparatus in Paper Storage Apparatus) In the embodiment shown in FIG. 4, a paper supply tray 65 as a paper storage apparatus is mounted on the paper supply apparatus 15 and picked up from the paper supply tray 65. The case where the paper is fed by the roller 21 is shown. In the example shown in FIG. 4, a bottom plate 66 for supporting the sheet is disposed inside the sheet feeding tray 65, and the bottom plate 66 is pushed up by the push-up arm 61, so that the height of the sheet P with respect to the pickup roller 21 is raised. It is configured to control the height.

As described above, the paper feeding device 15 to which the paper feeding tray 65 is mounted is provided with the roller unit 20, and the pickup roller 21 takes out the paper from the paper feeding tray. Feed roller 2
2 and the retard roller 47 perform the action of separating the sheets, so that the sheet that has been separated one by one is transported in the sheet path 16 by the transport roller device 48.
The separating device in which the feed roller 22 and the retard roller 47 are arranged to face each other is a device called a friction retard roller system, and the driving torque of the retard roller 47 is reversed in the sheet feeding direction. The retard roller 47 pushes back the lower sheet fed in the double feed state. Further, an insertion guide 67 is provided for guiding when the paper feed tray 65 is mounted on the paper feeding unit, and the paper feed tray is mounted via the insertion guide 67 so that the paper feeding device is provided. The paper feed tray can be mounted at an accurate position with respect to.

The push-up arm 61 of the driving device 60 is disposed with respect to the bottom plate 66 arranged on the paper feed tray, and the bottom plate 66 is raised by the push-up arm 61. It is configured as shown in FIG. The driving device 60 shown in FIG.
A substantially fan-shaped input gear 63 is arranged for an output gear of a drive gear device 64 connected to a drive device of the image forming apparatus main body, and a push-up arm 61 is attached to a shaft 62 provided on the gear 63. Then, by driving the drive gear device 64 little by little in accordance with the height of the paper, the bottom plate 66 is raised via the push-up arm 61 so that the height of the paper is maintained at a constant height. I do.

In the driving device 60, as described above, the driving gear device 64 is provided by using driving connection means (not shown) based on information from the sheet height detection sensor.
Is driven so that the paper supported by the bottom plate 66 is controlled to have a certain height. When the driving device 60 is driven, the operation of the detection by the sheet height detection device shown in FIG. 3 and the operation until the roller unit moves in the descending direction until the roller 21 presses the sheet are performed. The detection timing is set so as not to detect the arrival of the fed sheet, and the detection is performed by the sensor 45 or the like in a state where the pickup roller 21 of the roller unit is stabilized on the sheet. .

Therefore, by performing the operations of detecting the sheet height and detecting the presence or absence of the fed sheet at the timings described above, the information detected by each sensor can be vibrated by the swing of the roller unit. Is not affected, accurate detection information can be obtained. further,
In the apparatus of the present invention, when the driving device 60 is driven to raise the bottom plate, the paper fed from the paper feeding device is transported at a constant speed in the paper path. Only the control means for the driving device is configured to raise the push-up arm 61. Only when the driving mechanism connected to the driving device 60 is driving another member at a constant speed,
By performing a driving operation on the lifting arm 61,
By limiting the driving speed for the bottom plate, it is possible to accurately control the height at which the paper is raised.

In addition to using the paper feed tray 65 as described above, the paper detection mechanism shown in this embodiment can be applied to an apparatus using a large capacity tray 70 as shown in FIG. 6 as a paper storage device. is there. The large-capacity tray 70 shown in FIG. 6 is configured to have the same configuration as a tray generally used as a large-capacity sheet storage device, and has a bottom plate for supporting sheets inside the tray body. 71 is provided so as to be able to move up and down. The large-capacity tray 70 is provided with an insertion guide 74
, And can be positioned with respect to the sheet feeding device. Further, the bottom plate 71 employs means for disposing a wire 73 between the driving device 72 and winding the wire to raise the bottom plate 71.

In the large-capacity tray 70, as in the case of the paper feed tray shown in FIG. 4, the driving is performed based on the information of the paper height from the detecting means arranged corresponding to the roller unit. The apparatus 72 is driven to raise the bottom plate 71 so that the height of the sheet with respect to the pickup roller 21 is maintained constant. In addition, only when the paper is being conveyed at a constant speed in the paper path, the operation of raising the paper inside the large capacity tray is performed. As described above, the operation of lifting the sheet in the sheet storage device will be described with reference to FIG. In the image forming apparatus shown in FIG. 7, the paper fed from the paper feeding device is regulated by the rotation speed of the feed roller in a section where the speed of the paper is controlled by the feed roller 22 in the paper feeding section of each device. Is done. On the other hand, in the paper path 16, the transport operation is performed at a high speed by the transport roller device 48. That is, when the paper is transported at a high speed in the paper feeding unit, the feed roller 22 and the retard roller 47 in the paper separating unit are used.
As a result, the performance of the separation is reduced, and a problem that double feed is likely to occur occurs. Therefore, the sheet is conveyed at a low speed in the separating section, and the sheet is conveyed at a high speed in the sheet path 16 so that the time for the sheet to reach the image transfer section from the photosensitive drum 11 is shortened, and the copying is performed. To reduce the time required for

In the image forming apparatus according to the present embodiment in which the above-described transport mode is set, while the paper is being fed from the paper feeding device at the speed v1, the rising of the paper inside the paper storage device is performed. The operation is not performed, and the operation of raising the sheet is performed while the sheet is being conveyed in the sheet path 16 at a constant speed v2. As a result, the rising action of the sheet inside the sheet storage device is performed at a constant speed, so that the amount of rising of the sheet with respect to the driving time of the device is stabilized.

In the embodiment of the present invention, the case where each mechanism is provided in an electronic copying machine as an image forming apparatus has been described. However, each apparatus of the present invention is applicable to another apparatus such as a laser printer. It is also applicable. Further, the respective constituent members of the present invention are not only applied to the image forming apparatus having the above-described configuration, but can be easily applied to a recording apparatus using cut paper.

[0034]

According to the paper feeder of the present invention, the pickup roller is swung from a state in which the pickup roller is held at a position not in contact with the sheet until it is pressed by the sheet. During this time, the detecting operation for the sheet is prohibited, and the position of the pickup roller can be detected after the pickup roller is stabilized on the sheet.
In addition, it is possible to avoid a malfunction of the sensor due to the fluttering of the swinging mechanism, and it is possible to stably detect the sheet.

[Brief description of the drawings]

FIG. 1 is a plan view of a sheet feeding device of the present invention.

FIG. 2 is an explanatory diagram of a roller unit incorporated in the sheet feeding device of FIG.

FIG. 3 is a perspective view of a swing device provided in the device of FIG.

FIG. 4 is a side view when a paper feed tray is mounted on the paper feed device.

FIG. 5 is a perspective view of a driving device for a bottom plate of a sheet feeding tray.

FIG. 6 is an explanatory diagram in a case where a large-capacity tray of an elevator system is provided in a sheet feeding device.

FIG. 7 is an explanatory diagram of a sheet transport mechanism in the image forming apparatus.

FIG. 8 is a side view illustrating a configuration of a general image forming apparatus.

FIG. 9 is an explanatory diagram illustrating a configuration of a conventional sheet feeding device.

Claims (1)

(57) [Claims] 1. A pickup roller for taking out a sheet from a sheet storage device, a swing mechanism for swinging the pickup roller, and a holding means for holding the pickup roller in a state of being separated from the sheet via the swing mechanism. Moving means for moving the pickup roller from a state held by the holding means via the swing mechanism to a state where the pickup roller is pressed against the sheet when feeding the sheet from the sheet storage device; A sensor for detecting a swinging position of the swinging mechanism, wherein a sensing timing is set so that the sensing operation by the sensor is not performed while the pickup roller is moved by the moving means. A sheet feeding device for an image forming apparatus.