JP3078351B2 - Image forming apparatus and its separating apparatus - Google Patents

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 a color copying machine, a facsimile, and a printer, and more particularly to an image forming apparatus having a separating device for separating a transfer material from a rotating body such as an image carrier and a fixing roller. It is.

[0002]

2. Description of the Related Art Conventionally, in this type of image forming apparatus,
When transferring a toner image formed on an image carrier such as a photoreceptor onto a transfer material such as transfer paper to form an image, the image carrier may be separated from the image carrier without fail. Separating claws are placed in contact with the surface. Further, in an image forming apparatus provided with a fixing device for fixing a toner image on a transfer material by a fixing roller such as a heating roller, a separation claw is provided on the surface of the fixing roller in order to surely separate the transfer material from the fixing roller. It is placed in contact. Since the separation claw is brought into contact with the surface of the rotating body as described above, the surface of the rotating body is damaged with time, and an abnormal image is generated, so that the rotating body needs to be replaced. Therefore, in order to delay the replacement time of the rotating body, the separating claw is appropriately swung in the apparatus to increase the surface area of the rotating body with which the separating claw comes into contact, thereby minimizing local damage as much as possible. (For example, 60-1
59455, JP-A-64-50084). However, the conventional apparatus has a problem that the mechanism for swinging the separation claw is complicated, which leads to an increase in the number of parts, an increase in cost, and an increase in the size of the apparatus. For example, Japanese Patent Application Laid-Open No. Sho 64-50084 discloses a claw holding shaft which holds a separation claw and is movable in the axial direction of a rotating body, and a claw holding shaft which engages with the claw holding shaft and moves the claw holding shaft in a predetermined direction. In order to swing the separation claw by providing a cam member and a driving force transmitting mechanism for transmitting the driving from the driving source to the cam member, the driving force transmitting mechanism is replaced with a normal clutch or a spur gear. In addition, it is necessary to add a special member such as a swinging member that is supported by the claw holding shaft and has a fan-shaped tooth portion at one end and a ratchet claw at the other end. There still remains a problem that it is necessary to form an engaging ratchet portion, which leads to an increase in the number of parts, an increase in cost, and an increase in the size of the device. In addition, the actual opening 60
In JP-A-159455, a driving source, a cam member supported by the driving source, and a claw holding shaft which is engaged with a groove of the cam member and is movable in the axial direction of the rotating body are provided. Although the number of components is reduced due to the swinging of the separation claw, a dedicated driving source must be provided, and the problem of increased cost remains. In addition, when the toner adheres to the separation claw over time, toner stains are generated on the transfer material. Therefore, maintenance work such as appropriately removing and cleaning the separation claw is required. There is also a risk that a member constituting the separation claw moving mechanism, which is disposed around the separation claw, particularly on the device front side of the claw holding member, may obstruct the maintenance work.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide an image forming apparatus capable of swinging a separation claw at low cost and in a small space. A second object of the present invention is to provide an image forming apparatus capable of swinging the separation claw and having good maintenance workability of the separation claw.

[0004]

In order to achieve the first object, a separation device of an image forming apparatus according to the first aspect of the present invention contacts a surface of a rotating body to separate a transfer material from the surface of the rotating body. And a claw holding member that holds the separation claw and that is movable in a predetermined direction having a direction component perpendicular to the moving direction of the rotating body surface, and is engaged with the claw holding member. A driving member having a cam member for moving the claw holding member in the predetermined direction, a drive source capable of rotating forward and reverse, and a one-way clutch for transmitting drive from the drive source to the cam member. have a transmission mechanism, the upper SL drive source is a drive source of the rotating body, and said one-way clutch when rotating in the opposite orientation as during the drive source normal image forming operation, the driving Is transmitted. According to a second aspect of the present invention, there is provided an image forming apparatus including the separating device of the first aspect of the invention, wherein a coefficient means for counting an image forming operation time or the number of image forming operations is compared with a coefficient result of the coefficient means and a reference value. A comparison unit, and a drive source control unit that rotates the drive source in a direction opposite to that during a normal image formation operation after the image formation operation is completed, based on a comparison result of the comparison unit. Things. In order to achieve the second object, the image forming apparatus according to claim 3 , wherein the separation claw is disposed so as to be in contact with the rotating body surface to separate the transfer material from the rotating body surface; And a pawl holding member movable in a predetermined direction having a direction component perpendicular to the moving direction of the surface of the rotating body, and moving the pawl holding member in the predetermined direction by engaging with the pawl holding member. A claw holding member moving mechanism,
A face plate detachably attached to the front surface of the front side plate so as to cover at least a part of the maintenance opening of the front side plate of the apparatus; A member provided on the near side is attached to the face plate. The invention of claim 4 is
4. The image forming apparatus according to claim 3 , wherein the claw holding member moving mechanism is connected to the claw holding member via a connection member which can be separated and moved in the predetermined direction, and the claw holding member is mounted via the connection member. The cam includes a biasing mechanism for biasing the front side, a cam member having a cam surface with which the device front side end of the claw holding member abuts, and a drive transmission mechanism for transmitting drive to the cam member. A member is attached to the face plate.

[0005]

According to the first aspect of the present invention, when the drive source rotates in a predetermined direction, the drive is transmitted to the cam member via the one-way clutch to drive the cam member, thereby engaging with the cam member. Is moved in a predetermined direction to change the contact position of the separation claw on the surface of the rotating body. According to a fourth aspect of the present invention, the claw holding member moving mechanism moves the claw holding member in a predetermined direction to change the contact position of the separation claw on the rotating body surface. By removing from the front side plate, the members provided on the front side of the device with respect to the claw holding member among the members constituting the claw member holding member moving mechanism together with the face plate can also be removed.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus according to one embodiment. In the drawings, reference numeral 1 denotes a drum-shaped photoconductor as an example of a configuration of a latent image carrier, and the photoconductor drum 1 is driven to rotate counterclockwise when performing an image forming process. . First, the surface of the photoreceptor drum 1 is uniformly charged by the charging charger 2, and thereafter, the non-image portion is set to the neutralized state by the eraser 3. Next, exposure is performed at the exposure unit 4, and an electrostatic latent image is formed on the surface of the photosensitive drum 1. The electrostatic latent image is visualized as a toner image by the developing device 5, and the toner image is transferred by the transfer charger 8 to the transfer paper 7 sent from the registration roller 6. Thereafter, the transfer paper is made to be easily separated by the separation charger 9, and is separated from the surface of the photosensitive drum 1 by the charger 9 and the separation claw 50. After the transfer of the toner image is completed, residual toner adheres to the surface of the photosensitive drum 1 and is removed and collected by the cleaning device 12. That is, the toner remaining on the photosensitive drum 1 is scraped off and removed by the cleaning brush 13 and collected on the brush side. The remaining toner is scraped off by the cleaning blade 14 whose edge portion 14a is in contact with the surface of the photoconductor. On the other hand, the toner collected by the cleaning brush 13 is electrically drawn toward the collecting roller 15 to which the bias voltage is applied, and the drawn toner on the collecting roller 15 is scraped off by the blade 16. In this way, the toner on the surface of the photoconductor drum 1 is completely removed. After that, the surface of the photoconductor drum 1 is set to the neutralized state by the neutralization lamp 17. In this embodiment, the edge portion 1 of the cleaning blade 14 is used.
In order to remove the toner adhering to 4a, the photosensitive drum 1 is appropriately rotated in the opposite direction (clockwise) during the normal image forming operation after the image forming operation is completed.

FIG. 2 schematically shows a photoconductor driving unit. The photosensitive drum 1 has a hollow cylindrical shape, and front and rear openings are held by a front flange 27 and a rear flange 25. The front flange 27 and the rear flange 25 are rotatably supported by a drum shaft 29 that penetrates the photosensitive drum 1. A drum heater 30 having a smaller diameter than the photosensitive drum 1 is attached to the drum shaft 29. The rear end of the drum shaft 30 is non-rotatably supported by the main body rear plate, and the front end of the drum shaft 30 is non-rotatably supported by a face plate described later. A drum gear 24 is formed on the rear flange 25.
Is connected via a drum gear 23, a drum driving pulley 22, and a drum driving belt 21 to a main motor (not shown) which can be rotated forward and backward, whereby the drive from the main motor is transmitted to the photosensitive drum 1, and the photosensitive drum 1 Is rotationally driven on the drum shaft 29 in a predetermined direction. While the photosensitive drum 1 is rotating, the flanges 25 and 27 rotate together with the photosensitive drum 1, but the drum heater 30 and the drum shaft 29 do not rotate. An output gear 27a for driving a cam, which will be described later, is formed on the front flange 27.

FIG. 3 shows a support mechanism for the photosensitive drum 1 and the separation claw 50. The separation claw 50 is attached to the separation claw shaft 49. The rear end of the separation claw shaft 40 has a D-shaped cross section, which is inserted into and supported by a coupling 48 having a D-shaped recess, and the front end of the separation claw shaft 40 is attached to a holder 51. The photosensitive drum 1 is supported so as to penetrate through the formed hole, further extends toward the front side, penetrates a hole formed in a face plate 32 described later, and allows the separation claw 50 to come into contact with the surface of the photosensitive drum. Are provided in parallel with the axis. The coupling 48 is slidably supported by the holder 45 and is fixed to the front end of the pressurizing shaft 46 urged forward (in the direction of arrow F) by a spring 47. One end of the spring 47 is fixed to the holder 45 and the other end is fixed to the pressing shaft 47 with a screw, thereby applying clockwise turning power to the pressing shaft 47. This turning force causes the separation claw shaft 49 to rotate clockwise via the coupling 48, thereby causing the separation claw 50 to abut on the surface of the photosensitive drum 1. Here, the holder 45 is attached to the main body side plate 3.
The housing 1 is fixed to a housing (not shown) fixed to the housing 1 (eg, the housing of the cleaning device 12). The face plate 32 is attached to the front surface of the front plate 33 so as to cover the entire maintenance opening 60 of the front plate 33 of the main body, and is positioned by the pins 34 and 35 planted on the front plate 33 and is screwed. Is fixed to the front end surface of the drum shaft 29 by the knob 36 provided with the knob 36, thereby positioning and fixing the front end portion of the drum shaft 29. Also, face plate 3
2 is provided with a spring 37 and a movable spring cover 38 urged to be constantly pushed out by the spring 37. When the face plate 32 is mounted, the movable spring cover 38 pushes the front drum flange 27 to the rear side. To ensure the holding of the photosensitive drum 1 by the flanges 25 and 27. The face plate 32 has a cam 43 for swinging a separation claw shaft 49 in the axial direction of the photosensitive drum 1, and the cam 43 has a photosensitive drum 1 as a drive source.
And a drive transmission mechanism for transmitting the drive from the motor. As the cam 43, for example, an end cam having a gear formed on a side surface is used, and is provided rotatably at a position where the front end of the separation claw shaft 49 can abut on the cam surface. The drive transmission mechanism includes, for example, an input gear 39 meshing with the output gear 27a of the front flange 27, an output gear 42 meshing with a gear of the end face cam 43,
A shaft 40 to which the input / output gears 39 and 42 are fixed, a bearing 41 for rotatably mounting the shaft 40 to the face plate 32, and a one-way clutch press-fitted into the output gear 42 and provided on the shaft 40. Be composed. This one-way clutch rotates the photosensitive drum 1 during a normal image forming operation (see FIG. 1).
Sometimes, it is free to transmit the drive and transmit the rotation of the shaft 40 to the output gear 42 during the rotation in the opposite direction.

In the above configuration, the photosensitive drum 1 is driven to rotate in the direction of arrow A during a normal image forming operation. Therefore, the gear 27 of the front flange 27 of the photosensitive drum 1
The input gear 39 meshing with a rotates in the direction of arrow D. At this time, since the one-way clutch is free as described above, the output gear 42 does not rotate. On the other hand, when the photosensitive drum 1 is rotationally driven in the direction opposite to that during the normal image forming operation (the direction of arrow B), the input gear 39 and the shaft 4 are rotated.
0 rotates in the direction of arrow C, and the one-way clutch transmits this rotation to the output gear 42 to rotate the output gear 42 in the direction of arrow C. Therefore, the end face cam 43 in which the output gear 42 meshes with the gear formed on the side face rotates in the direction of the arrow E to displace the separation claw shaft 49 in contact with the cam face in a predetermined direction. Then, the position on the photosensitive drum 1 where the separation claw 50 contacts is changed. The amount of displacement of the separation claw shaft 49 is determined by the amount of reverse rotation of the photosensitive drum 1 and each gear 27a,
It is determined by the setting of the number of teeth such as 39 and 42. For example, 1
The reverse rotation operation of the photosensitive drum 1 causes the photosensitive drum surface to move by 10 to 20 mm, thereby setting the separation claw shaft 49 to move by 1.5 to 2.0 mm. In this example, since the maximum displacement x of the end face cam 43 is set to 5.0 mm, the separation claw shaft is moved by 1.5 to 2.0 mm every time the photosensitive drum 1 is rotated in the reverse direction, which is executed at a timing described later. 49
Is moved, and the maximum variation is 5.0 mm in 3 to 4 reverse rotations.
(Equivalent to a rotation angle of 180 ° of the end face cam 43), and thereafter, the separation claw shaft 49 is moved in the opposite direction by 1.5 to 2.0 mm each time the photosensitive drum 1 is rotated in the reverse direction. Let it. Thus, the contact position of the separation claw 50 with the photosensitive drum 1 is swung within the width of the maximum displacement of 5.0 mm.

When removing the separation claw shaft 49, first,
The knob 36 is removed and the face plate 32 is removed from the front side plate 33.
At this time, the end face cam 43 provided on the face plate 32 and the drive transmission mechanism are also removed. Therefore, the separation claw shaft 4
9 and the holder 51 are exposed to the maintenance opening of the front side plate 33. Here, the front end of the separation claw shaft 49 is pushed into the inner side of the apparatus against the urging force of the pressing shaft 46 (in the direction of arrow F), and the front end is pulled out from the through hole of the holder 51.
Take out the whole. At this time, the pressing shaft 46 and the like remain in the main body together with the coupling 48. Thereby, maintenance such as cleaning and replacement of the separation claw can be easily performed. When the separation claw shaft 49 is set, the rear end of the separation claw shaft 49 is inserted into the coupling 48 and pushed in against the urging force of the pressing shaft 46, and the front end of the separation claw shaft 49 is set in the holder. After passing through the through hole 51 from the back side, the face plate 32 is attached.

The reverse rotation of the photosensitive drum 1 is executed, for example, every time the total operation time of the image forming operation (cumulative operation time) reaches 10 minutes, or every time the number of image forming operations reaches 1000 sheets. You can do it. FIG. 4 shows a flowchart of the main motor rotation control in the former case. In Step 1, it is determined whether or not the image forming operation (JOB) has been completed.
To stop the main motor (photoconductor drive source), and in step 3, it is determined whether or not the total time of the image forming operation has reached 10 minutes by referring to the coefficient means for counting the total operating time of the image forming operation. I do. If it is determined that the time has reached 10 minutes, the coefficient means (main motor operation time counter) is cleared in step 4 and the main motor is reversely rotated by 50 msec in steps 5 and 6, whereby the separation is performed as described above. The claw 50 is moved, for example, by 1.5 to 2.0 mm. FIG.
Fig. 2 shows a simple block diagram showing the present apparatus. A general CPU 61 controls the main motor and counts the operation time. 62 is a main motor (38V DC),
Forward and reverse rotation is possible. 63 is a power supply for operating the main motor.

[0012]

According to the first and second aspects of the present invention, when the drive source rotates in a predetermined direction, the drive is transmitted to the cam member via the one-way clutch to drive the cam member. Since the contact position of the separation claw on the surface of the rotating body is changed by moving the claw holding member engaged with the cam member in a predetermined direction, a simple configuration of a drive source capable of normal and reverse rotation and a one-way clutch can reduce The separation claw can be rocked at low cost and space . Further, as the drive source, since using the driving source of the rotary end, it is not necessary to provide a separation claw swing dedicated drive source, further, a low-cost, it is possible to reduce the space. Further, according to the invention of claim 2 , a coefficient means for counting the image forming operation time or the number of image forming operations, a comparing means for comparing the coefficient result of the coefficient means with a reference value, and based on a comparison result of the comparing means A driving source control means for rotating the driving source in a direction opposite to that during the normal image forming operation after the image forming operation is completed, whereby the separating claw is moved to each position within the moving range on the rotating body. Since the image forming operation time or the number of times of the image forming operation performed during the stationary state is the same, the damage of the rotating body can be made uniform within the moving range, and as a result, the time of replacing the rotating body can be further delayed. According to the invention 請 Motomeko 3 moves the pawl retaining member in a predetermined direction by the claw holding member moving mechanism changes the contact position of the separation claw on the rotating member surface, and, when the maintenance separation claw, the By removing the face plate from the front plate of the apparatus, it is possible to remove a member provided on the front side of the claw holding member among the members constituting the claw member holding member moving mechanism together with the face plate. The operation of the holding member can be facilitated.
Further, according to the invention of claim 4 , the claw holding member moving mechanism is connected to the claw holding member via the connection member which can be separated and moved in the predetermined direction, and the claw holding member is connected via the connection member. A biasing mechanism for biasing the device toward the front side, a cam member having a cam surface against which the device front side end of the claw holding member abuts, and a drive transmission mechanism for transmitting drive to the cam member. The cam member is attached to the face plate, whereby the claw holding member can be separated from the connection member and easily taken out of the apparatus, so that the maintenance of the separation claw can be further facilitated.

[0012]

According to the first, second and third aspects of the present invention, when the drive source rotates in a predetermined direction, the drive is transmitted to the cam member via the one-way clutch to drive the cam member. By moving the claw holding member engaged with the cam member in a predetermined direction to change the contact position of the separation claw on the surface of the rotating body, a simple structure of a drive source capable of normal and reverse rotation and a one-way clutch is used. There is an excellent effect that the separation claw can be swung with low cost and space saving. Further, according to the second aspect of the present invention, since the driving source at the rotating end is used as the driving source, there is no need to provide a driving source dedicated to the swinging of the separation claw, and the cost and space can be further reduced. I can do it. Further, according to the invention of claim 3, a coefficient means for counting the image forming operation time or the number of times of image forming operation, a comparing means for comparing a coefficient result of the coefficient means with a reference value, and a comparing means based on the comparison result of the comparing means A driving source control means for rotating the driving source in a direction opposite to that during the normal image forming operation after the image forming operation is completed, whereby the separating claw is moved to each position within the moving range on the rotating body. Since the image forming operation time or the number of times of the image forming operation performed during the stationary state is the same, the damage of the rotating body can be made uniform within the moving range, and as a result, the time of replacing the rotating body can be further delayed. According to the invention of claim 4, the claw holding member moving mechanism moves the claw holding member in a predetermined direction to change the contact position of the separation claw on the surface of the rotating body. By removing the face plate from the front plate of the apparatus, it is possible to remove a member provided on the front side of the device relative to the claw holding member among the members constituting the claw member holding member moving mechanism together with the face plate. The operation of the claw holding member can be facilitated.
Further, according to the fifth aspect of the present invention, the claw holding member moving mechanism is connected to the claw holding member via the connecting member which can be separated and moved in the predetermined direction, and the claw holding member is connected via the connecting member. A biasing mechanism for biasing the device toward the front side, a cam member having a cam surface against which the device front side end of the claw holding member abuts, and a drive transmission mechanism for transmitting drive to the cam member. The cam member is attached to the face plate, whereby the claw holding member can be separated from the connection member and easily taken out of the apparatus, so that the maintenance of the separation claw can be further facilitated.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of an electrophotographic apparatus according to an embodiment.

FIG. 2 is an exploded perspective view of the photosensitive drum 1 in FIG.

FIG. 3 is a plan view of the vicinity of a photosensitive drum 1 in FIG.

FIG. 4 is a flowchart of photosensitive drum drive control of the copying machine.

FIG. 5 is a block diagram of an electrical unit of the copying machine.

[Explanation of symbols]

Reference Signs List 1 photoreceptor drum, 31 main body rear plate 32 face plate, 33 main body front plate 39 input gear, 40 shaft 41 bearing, 42 output gear 43 end cam, 45 holder 46 pressing shaft, 47 spring 48 coupling, 49 separation claw shaft 50 separation Claw, 51 Holder 60 Maintenance opening

Claims (4)

(57) [Claims] A separating claw arranged to come into contact with the surface of the rotating body for separating the transfer material from the surface of the rotating body; and a separating claw that holds the separating claw and is perpendicular to a moving direction of the rotating body surface. A claw holding member movable in a predetermined direction having various directional components, a cam member for engaging the claw holding member to move the claw holding member in the predetermined direction, and a drive source capable of rotating forward and reverse. the drive from the drive source have a driving force transmission mechanism having a one-way clutch for transmitting to said cam member, the drive source is a drive source of the rotating body, and, the one
The directional clutch is used when the above drive source is in normal image forming operation.
A separating device for an image forming apparatus , wherein a driving force is transmitted when rotating in an opposite direction . 2. An image forming apparatus according to claim 1, further comprising a separating device.
And a coefficient for counting the image forming operation time or the number of image forming operations.
Means, a comparing means for comparing a coefficient result of the coefficient means with a reference value, and after completion of the image forming operation based on the comparison result of the comparing means.
The above drive source is turned in the opposite direction to that during normal image forming operation.
An image forming apparatus provided with a driving source control unit for rotating the image forming apparatus. 3. A rotating device for separating a transfer material from a surface of a rotating body.
A separating claw arranged so as to be in contact with the surface of the rotating body; and
Claw holder that can move in a predetermined direction with a vertical direction component
And the claw holding member is engaged with the claw holding member to move the claw holding member in the predetermined direction.
Moving the claw holding member moving mechanism and at least a part of the maintenance opening of the apparatus front side plate.
Setting a faceplate mounted for and removable in front of the front side plate
The claw holding portion of the members constituting the claw holding member moving mechanism
A member provided on the front side of the device relative to the material was attached to the face plate.
Image forming device. 4. The apparatus according to claim 1, wherein the pawl holding member moving mechanism is adapted to move the predetermined direction.
Connected to the claw holding member via a connection member
And the claw holding member is moved to the front side of the device through the connection member.
Mechanism and a device front end of the claw holding member
A cam member having a cam surface with which a portion abuts, and
A drive transmission mechanism for transmitting drive, wherein the cam member is mounted on the face plate.
Item 3. The image forming apparatus according to Item 3.