JPH0683218A - Transfer roller device - Google Patents

Abstract

PURPOSE:To prevent the abrasion of a cleaning blade, etc., and to stabilize an image over a long period by providing a contact/uncontact control means separating a transfer roller from an image forming body and a rotation control means stopping the rotation of the transfer roller. CONSTITUTION:The transfer roller 27 is rotated/driven in such a manner that rotational driving force from a driving means is transmitted via transmission means 33, 37, 38, 54, 55 and 60 and provided so as to be in contact/uncontact with the image carrier by contact/uncontact means 34, 44, 50 and 51. The contact/uncontact control means 35 driving the contact/uncontact means 34, 44, 50 and 51 to separate the transfer roller 27 from the image forming body after the tailing edge of a transfer material passes the press-contact part of the transfer roller 27 with the image forming body is provided. Moreover, the rotation control means 65 interrupting the transmission of the rotational driving force from the driving means to the transmission means to stop the rotation of the transfer roller 27 after the tailing edge of the transfer material passes the press-contact of the transfer roller 27 with the image carrier is provided. Thus, the abrasion of the cleaning blade 59, etc., in press-contact with the transfer roller 27 is reduced and service life can be prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer roller device which is provided in an image forming apparatus such as a copying machine or a printer and transfers an image onto a sheet or the like.

[0002]

2. Description of the Related Art In a full-color copying machine, usually, yellow, magenta, and cyan toner images are individually formed on a photoconductor, and then each toner image is transferred to a transfer belt which is pressed against the photoconductor. By doing so, the images are overlapped. Then, the sheet conveyed by the registration roller at a predetermined timing is pressed against the transfer belt by the transfer roller, so that the toner image on the transfer belt is transferred to the sheet.

Conventionally, in the transfer roller device provided in the above-mentioned full-color copying machine, the transfer roller is provided so that it can be brought into contact with or separated from the transfer belt. For example, a unit frame 85 as shown in FIG. It is rotatably attached. The coupling-equipped gear 95 mounted on the unit frame 85 is coupled to the coupling coupling 90 mounted on the drive transmission shaft 97, so that a drive unit composed of a motor and a gear train (not shown) is The driving force is transmitted and the transfer roller 87 is rotated.

That is, the driving force transmitted to the coupling gear 95 is fixed to the first driving gear 94 that meshes with the coupling gear 95, and the second driving gear fixed to the same idle shaft 81 as the first driving gear 94. It is transmitted to the transfer roller drive gears 88, 88 fixed to both ends of the transfer roller 87 via 82.

A third drive gear 83 provided at the end of the idle shaft 81 opposite to the first drive gear 94.
Engages with the input gear 91 of the electromagnetic clutch 89 for controlling the drive of the lower registration roller 86b and the idle gear 92a. As a result, the transfer roller 87
The upper and lower registration rollers 86a and 86b, which convey the sheet at a predetermined timing to the contact portion between the transfer belt and the transfer belt, are rotationally driven.

Further, the idle gear 92a described above meshes with the input gear 98 of the spring clutch 96 which controls the drive of the cam shaft 93 to which the cam 100 is fixed.
The rotation of the cam 100 transmitted from the input gear 98 is controlled by turning on / off a solenoid (not shown) that controls the drive of the spring clutch 96. When the cam 100 rotates, the transfer roller 87 is rotatably held. The plate 101 that rotates rotates around the idle shaft 81,
The transfer roller 87 moves up and down.

Therefore, the transfer roller 87 is provided by the mechanism as described above so that it can be brought into contact with or separated from the transfer belt carrying the toner image transferred from the photosensitive member. At the start of transfer, the solenoid is turned on. By rotating the cam 100, the paper is raised so as to come into pressure contact with the transfer belt, and when the transfer is completed and the paper passes the transfer roller 87, the solenoid is turned on again,
It separates from the transfer belt and descends.

By providing the transfer roller 87 so as to be separable from the transfer belt in this manner, the transfer roller 8 can be transferred only when the toner image is transferred from the transfer belt to the sheet.
7 and the transfer belt are brought into pressure contact with each other, and in other cases, the pressure contact between the transfer roller 87 and the transfer belt is released, whereby abrasion of the transfer belt and the transfer roller 87 can be prevented, and life can be extended.

[0009]

However, in the copying machine having the transfer roller device 84 as described above, the transfer belt, the transfer roller 87, the cam 100 for moving the transfer roller 87 up and down, and the like are driven by the same driving device. Since the transfer belt is driven to rotate, it is necessary to continue the rotation for cleaning the residual toner even after the transfer roller 87 is separated. Therefore, the transfer roller 87 is inevitably rotated after being separated from the transfer belt and lowered. Will continue.

Further, since the residual toner on the transfer belt is adsorbed on the surface of the transfer roller 87 and is contaminated,
A cleaning blade for removing this is pressed. Therefore, if the rotation of the transfer roller 87 is continued after being separated from the transfer belt 12 as described above, the abrasion of the cleaning blade and the transfer roller is accelerated.

As a result, the life of an expensive transfer roller formed by Teflon coating and polishing the surface in order to make the transfer uniform and improve the peeling property of the paper is shortened, and the transfer failure is likely to occur. Is occurring.
Further, when a worn cleaning blade is used, there is a problem that cleaning failure of the transfer roller occurs and residual toner adheres to the back surface of the paper to cause stains.

[0012]

In order to solve the above-mentioned problems, a transfer roller device according to a first aspect of the present invention sandwiches a transfer material between a pressure contact portion between an image forming body and the transfer roller to form a transfer roller and an image forming device. The image on the image forming body is transferred to the transfer material while the transfer material is being sent while rotating each body, and the rotational driving force from the driving means is transmitted to the transfer roller via the transmitting means. In the transfer roller device which is driven to rotate by the contacting means so as to be able to contact and separate from the image forming body by the contacting and separating means, the rear end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body and then contacts and separates. Separation / contact control means for driving the means to separate the transfer roller from the image forming body, and rotational driving force from the driving means to the transmitting means after the rear end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body. Of the transfer roller It is characterized in that the rotation control means for stopping the rotation is provided.

Further, in order to solve the above-mentioned problems, the transfer roller device according to the invention of claim 2 sandwiches the transfer material between the pressure contact portions of the image forming body and the transfer roller, and rotates the transfer roller and the image forming body respectively. While the transfer material is being sent while being transferred, the image on the image forming body is transferred onto the transfer material, and the above-mentioned transfer roller is rotationally driven by the rotational driving force from the driving means being transmitted through the transmitting means. In the transfer roller device provided so as to be capable of being brought into contact with and separated from the image forming body by the separating means, the separating means is driven after the rear end of the transfer material has passed through the pressure contact portion between the transfer roller and the image forming body. And a contact / separation control unit that separates the transfer roller from the image forming body, and the transfer of the rotational driving force from the drive unit to the transfer unit is interrupted after a predetermined time has elapsed from the separation operation of the transfer roller. Stopped spinning And rotation control means is characterized in that provided that.

Further, in order to solve the above-mentioned problems, the transfer roller placing device according to the third aspect of the present invention sandwiches the transfer material between the pressure contact portions of the image forming body and the transfer roller to form the transfer roller and the image forming body respectively. While the transfer material is being sent while being rotated, the image on the image forming body is transferred onto the transfer material, and the above-mentioned transfer roller is rotationally driven by the rotational drive force from the drive means being transmitted through the transmission means. When the rotational driving force is transmitted from the transmission means in the transfer roller device that is provided so as to be capable of being brought into and out of contact with the image forming body by the separating means, while the transfer roller is rotated by the rotational driving force, the transfer roller is transferred. When the roller is in pressure contact with the image forming body and the rotational driving force is not transmitted from the transmitting means, the driving force transmitting switching means is provided which is driven by the rotation of the image forming body to rotate the transfer roller. It is characterized in that there.

[0015]

According to the structure of the present invention, after the trailing edge of the transfer material has passed through the pressure contact portion between the transfer roller and the image forming body, the contact / contact control means drives the contact / contact means so that the transfer roller forms an image. While being separated from the forming body, the rotation control means cuts off the transmission of the rotational driving force to the transmission means, and the rotation of the transfer roller is stopped. That is, the rotation of the transfer roller is performed only when the transfer roller is pressed against the image forming body. Therefore, in order to remove the toner adhering to the transfer roller, for example, when the cleaning blade is constantly in pressure contact with the transfer roller, wear of the transfer roller and the cleaning blade is prevented and life is prolonged,
A stable image can be obtained for a long period of time without causing transfer failure and cleaning failure.

According to the second aspect of the present invention, after the rear end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body, the contact / contact means is driven by the contact / contact control means to transfer the image to the transfer roller. The rotation control means cuts off the transmission of the rotational driving force to the transmission means, and the rotation of the transfer roller is stopped after the transfer roller is separated from the formed body and after a predetermined time has passed from the separation operation of the transfer roller. Has become.

If, for some reason, a malfunction occurs and the transfer roller is not separated from the image forming body and only the rotation of the transfer roller is stopped, the image forming body continues to rotate for cleaning residual toner. Since the transfer roller, which has stopped rotating, is pressed into contact with the transfer roller, scratches and the like occur on both the transfer roller and the image forming body, causing a problem of transfer failure.

However, as described above, by controlling the rotation stop of the transfer roller to be delayed from the separation operation, even if the transfer roller is not separated, the image forming body is rotated. Since the continuous transfer roller is pressed, the surface smoothness can be maintained and the life can be extended without damaging both.
Transfer defects can be prevented. Further, by setting the time for delaying the rotation stop of the transfer roller to be a short time, it is possible to prolong the life of the cleaning blade that is pressed against the transfer roller, as in the invention according to claim 1. A stable image can be obtained over a long period of time.

According to the third aspect of the invention, even if the rotational driving force is not transmitted from the transmission means, the transfer roller is pressed by the driving force transmission switching means to the image forming body as long as it is pressed against the image forming body. It is designed to rotate following the rotation of. Therefore, even if for some reason a malfunction occurs, the transfer roller does not separate from the image forming body, and only rotation is stopped, the transfer roller continues to rotate as the image forming body rotates. The surface smoothness of the transfer roller and the image forming body can be maintained and the life can be extended. As a result, transfer failure can be prevented and a stable image can be obtained for a long period of time.

[0020]

【Example】

[Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
The explanation is based on the following.

As shown in FIG. 2, a full-color copying machine having a transfer roller device according to this embodiment (hereinafter referred to as a copying machine) is formed of hard transparent glass on the upper end thereof, and a document 47 is placed thereon. The original placing table 1 to be placed is provided.
Below the document table 1, a light source lamp 2a for irradiating the document 47 with light, a mirror 2b for guiding the reflected light from the document 47 to the photoconductor drum 3, and an image formed on the optical path of the reflected light. An exposure optical system 2 including a lens 2c and a filter device 2d having color filters of three primary colors of red, green, and blue is provided.

The photosensitive drum 3 which is irradiated with the reflected light from the original 47 is rotatably provided in the direction A in the drawing.
Prior to the exposure by the exposure optical system 2, a charging charger 4 for uniformly charging the surface of the photoconductor drum 3 is provided around the periphery of the photoconductor drum 3.
An electrostatic latent image is formed on the top. On the downstream side of the charger 4 around the photosensitive drum 3,
The developing tanks 7 to 10, the intermediate transfer device 11, the cleaning device 6, and the charge eliminating lamp 5 are arranged in this order.

The developing tanks 7 to 10 contain black, yellow, magenta, and cyan toners, respectively. The toner supplied from each of the developing tanks 7 to 10 adheres to the electrostatic latent image formed on the photosensitive drum 3 so that a toner image is formed on the photosensitive drum 3. Has become.

The intermediate transfer device 11 includes a transfer belt (image forming body) 12 formed in the shape of an endless belt, and rollers 13a, 13b and 13c for driving the transfer belt 12 to rotate.
The transfer belt 1 transfers the toner image formed on the photosensitive drum 3.
2 includes intermediate transfer rollers 45, 45 that press the transfer belt 12 against the photosensitive drum 3 for transferring the image onto the photosensitive drum 3. A cleaner 14 that removes toner remaining on the transfer belt 12 is provided at a position facing the roller 13 a with the transfer belt 12 interposed therebetween.

The cleaning device 6 collects the toner remaining on the photosensitive drum 3 after the toner image is transferred onto the transfer belt 12. The discharging lamp 5 removes the residual potential of the photosensitive drum 3 before the next charging by the charging charger 4.

Below the intermediate transfer device 11, a transfer roller device 24 which is detachable from the main body of the copying machine is arranged. The transfer roller device 24 is the same as the transfer belt 12 described above.
The transfer roller 27 provided at a position facing the roller 13c with the sheet interposed therebetween, and the upper registration roller 26a and the lower registration roller 26a for supplying the paper (transfer material) 15 to a pressure contact portion formed by the roller 13c and the transfer roller 27 at a predetermined timing. Registration roller 26b, transfer roller 27, and upper registration roller 2
6a and a unit frame 25 that supports the lower registration roller 26b.

In the vicinity of the transfer roller 27, a peeling plate 28 for sending the paper 15 after the transfer of the toner image toward the conveying belt 29 provided on the paper output side of the transfer roller device 24 is arranged. . Incidentally, this transfer roller device 2
The more detailed structure, drive system, etc. of 4 will be described later.

On the paper feed side of the intermediate transfer device 11, there are provided paper feed cassettes 16 and 17 in which paper 15 is stored and which is detachable from the main body of the copying machine, and a paper feed tray 18 on which the paper 15 is placed. ing. This paper cassette 16 ・ 1
In the vicinity of 7 and the paper feed tray 18, there are provided paper feed rollers 19, 20, 21 for carrying the paper 15 to the upper and lower registration rollers 26a, 26b, and carry rollers 22, 23, etc. Further, a fixing device 30 having fixing rollers 31 and 31 for heating and fixing the transferred toner image on the paper 15 on the paper output side of the transport belt 29, and the paper 15 after fixing are discharged to the outside of the machine. Output rollers 32, 32 are provided.

Next, the transfer roller device 24 will be described in detail with reference to FIG.

Unit frame 2 of transfer roller device 24
5, a transfer roller 27 and upper and lower registration rollers 26a and 26b are rotatably attached, respectively. Above the upper and lower registration rollers 26a and 26b, a sheet is guided to a conveyance path. A paper guide 36 is provided.

Thus, the upper and lower registration rollers 2
Since 6a and 26b are attached to the same unit frame 25 as the transfer roller 27 and are detachably provided from the main body of the copying machine, the upper and lower registration rollers 26a and 2b are provided.
Maintainability when replacing and cleaning 6b is improved, and the transfer roller 27 and the upper and lower registration rollers 26a and 26b are aligned with the transfer roller device 24 removed from the copying machine main body. Therefore, both can be held in a normal positional relationship.

When the insertion direction of the transfer roller device 24 into the main body of the copying machine is the front side, a gear 55 with a coupling is rotatably attached to the front end portion (right end portion in the figure) of the unit frame 25. When the transfer roller device 24 is inserted into the main body of the copying machine and the positioning is performed, the gear 55 with the coupling is attached to one end portion of the roller drive transmission shaft 67 provided on the side of the main body of the copying machine. It is adapted to be connected to the attached drive connection coupling 60 for rollers. At the other end of the roller drive transmission shaft 67, an electromagnetic clutch (rotation control means) 65 that controls the transmission of the driving force is provided.
The input gear 66 of is engaged with a transmission gear 68 which is rotated by a driving force from a drive unit 57, which will be described later, which is composed of a motor, a gear train, and the like, which are not shown.

The roller drive transmission shaft 67 has a spring 61 between the electromagnetic clutch 65 and the roller drive coupling coupling 60, and an E ring for restricting the movement of the spring 61 toward the electromagnetic clutch 65. 62 and 62 are interposed. The roller drive coupling 60 is
When the roller drive transmission shaft 67 is prevented from rotating and is pressed by the spring 61 toward the tip end side of the roller drive transmission shaft 67, and when coupled with the gear 55 with a coupling, the spring 61 is connected to the electromagnetic clutch 65. It is designed to compress in the direction. Then, the electromagnetic clutch 65 is turned on.
In this state, the driving force from the driving unit 57 is transmitted by the transmission gear 68.
When it is transmitted to the input gear 66 via the roller drive coupling 60, the roller drive coupling 60 is rotated together with the roller drive transmission shaft 67 to rotate the gear 55 with the coupling.

The idle shaft 33, which is arranged substantially parallel to the transfer roller 27, has a gear 55 with a coupling on the front end side thereof.
The first drive gear 54 that meshes with is fixed, and
Second drive gears 37, 37 meshing with transfer roller drive gears 38, 38 provided at both ends of the transfer roller 27 are provided near both ends thereof, and further, at the rear end side, a lower registration roller 26b is provided. A third drive gear 43 that meshes with the registration roller drive gear 39 provided at the rear end portion is provided. It is also possible to provide a spring clutch or the like at the end of the lower registration roller 26b. In this case, in addition to the rotational drive of the transfer roller 27, the rotational drive of the lower registration roller 26b can be independently controlled. it can.

Below the third drive gear 43, an auger shaft drive gear 41 for rotationally driving the auger shaft 42 is provided. The auger shaft 42 includes a screw (not shown) for discharging the waste toner scraped off the transfer roller 27 by the cleaning blade 59 described later. Further, between the third drive gear 43 and the auger shaft drive gear 41, a first idle gear 40b that meshes with the third drive gear 43, and a mesh with the auger shaft drive gear 41 and the first idle gear 40b. Second idle gear 40
and a are provided.

As described above, the roller driving connection coupling 60, the coupling-equipped gear 55, the various gears 37, 38, 54, etc. constitute the transmission means of the present transfer roller device.

Further, at one end of the cam drive transmission shaft 63, which is disposed substantially parallel to the roller drive transmission shaft 67,
A cam drive gear 64 that meshes with the input gear 66 is provided. Similar to the roller drive transmission shaft 67, an E ring 62 and a spring 61 are attached to the cam drive transmission shaft 63, and a cam drive coupling coupling 69 is attached to the other end.

On the other hand, below the lower registration roller 26b, a cam shaft 44 to which the cams 50 and 50 are fixed is disposed, and in front of the cam shaft 44, a cam drive coupling coupling 69 is connected. A coupling 56 is provided. A spring clutch 34 that controls the rotational drive of the cam shaft 44, and a solenoid (separation / contact control means) 35 that controls the drive of the spring clutch 34 are provided on the front end side of the cam shaft 44.

The plates 51, 51 having cam abutting portions 51a, 51a with which the upper end surfaces of the cams 50, 50 abut are
As shown in FIG. 3, the transfer roller 27 and the idle shaft 33 are
Is rotatably supported. Also, the plates 51, 51
Leaf springs 52, 52 are attached to the cam springs 50, 50 for abutting against the lower end surfaces of the cams 50, 50 and for maintaining the contact state between the contact portions 51a, 51a and the cams 50, 50. Cam 50
When the 50 rotates, the plates 51 rotate about the idle shaft 33, and the transfer roller 27 is moved up and down.

That is, when the maximum eccentric portion of the cam 50 is in contact with the contact portion 51a of the plate 51, the transfer roller 27 is in a state of being separated from the transfer belt 12, but the cam 50 is B When the plate spring 52 is gradually rotated, the plate spring 52 is gradually pushed down so that the plate 51 moves the transfer roller 27 around the idle shaft 33.
Begins to rotate in the direction of approaching. When the cam 50 rotates to the position shown in FIG. 4, the transfer roller 27 comes into contact with the transfer belt 12. Further, when the cam 50 is rotated by θ ° and the leaf spring 52 is bent by Lmm, the transfer roller 27 causes the transfer belt 12 to have a predetermined pressure as shown in FIG.
Is pressed against the upper and lower registration rollers 2
The toner image is transferred to the sheet 15 conveyed between 6a and 26b.

On the other hand, the transfer roller 27 is the transfer belt 12
At the time of shifting from the pressure contact state to the separated state to the separated state, the plate 50 rotates in the direction to move the transfer roller 27 away from the transfer belt 12 by further rotating the cam 50 by half a turn in the B direction, and the transfer roller 27 is moved as shown in FIG. Descend to the position shown in. Further, in order to remove the toner adhering to the transfer roller 27 between the plates 51, 51, the transfer roller 27
There is provided a cleaning blade 59 which is brought into pressure contact with the micro blade and a micro switch 46 which detects the position of the transfer roller 27 which moves up and down.

As described above, the spring clutch 34, the cam shaft 44, the cams 50, 50, the plates 51, 51, etc. constitute the separating / contacting means of the present transfer roller device.

In the copying machine of this embodiment, as shown in FIG. 6, the timer 48 for counting the time after the output of a copy start signal, which will be described later, and the length of the designated paper 15 are detected. Depending on the output signals of the timer 48 and the paper length detection means 49,
By controlling the drive unit 57, the solenoid 36, the electromagnetic clutch 65, and the like, the control device (rotation control means, separation / contact control means) that controls the timing of starting or stopping the rotation and vertical movement of the transfer roller 27, etc. )
53 and 53 are provided.

In the above construction, the operation for copying will be described with reference to the flow chart shown in FIG. 7 and the timing chart in FIG. 8 When the copying machine is in the standby state, the transfer roller 27 stops rotating. At the same time, the transfer belt 12 and the transfer roller 27 are separated from each other. When the size of the paper 15 is selected by the operator or the like, the length of the paper 15 is determined by the paper length detecting means 49 (S).
1). Then, when the copy button is pressed, the charging of the photosensitive drum 3 is started by the charging charger 4, the transfer belt 12 starts to rotate, and a predetermined position on the transfer belt 12 is read by a sensor (not shown). For example, after the transfer belt 12 starts rotating, T ₀ (se
After c), a copy start signal is generated (S2). The copy start signal causes the exposure optical system 2 to start scanning the original, and an electrostatic latent image is formed on the photosensitive drum 3. Since the generation of the copy start signal is the standard for all operations,
The time when this copy start signal is issued is 0,
The timer 48 is reset.

Then, depending on the color of the toner used, toner is supplied from any of the developing tanks 7 to 10 after a predetermined time has elapsed from the generation of the copy start signal, and electrostatic charges on the photosensitive drum 3 are generated. The latent image is developed to form a toner image. Next, the toner image is intermediately transferred to the transfer belt 12. After the intermediate transfer, the residual toner on the photosensitive drum 3 is removed by the cleaning device 6, and further,
The residual potential on the photoconductor drum 3 is removed by irradiating it with light from the charge eliminating lamp 5. When performing full-color copying, the above-described operations such as charging, exposure, development, intermediate transfer, and static elimination are repeated three times (yellow, cyan, magenta), and images are superimposed on the transfer belt 12. .

When a predetermined time T ₁ (sec) corresponding to the sheet size has passed from the generation of the copy start signal (S3),
A paper feed start signal is generated (S4), the paper feed of the paper 15 from the paper feed cassettes 16 and 17 or the paper feed tray 18 is started according to the previously selected paper size, and the electromagnetic clutch 65 is turned on. (S5). As a result, the driving force from the driving unit 57 is transmitted to the transmission gear 68,
Transfer roller drive gears 38, 38 via the input gear 66, the roller coupling 60, the coupling-equipped gear 55, the first drive gear 54, and the second drive gear 37, 37.
And the transfer roller 27 starts to rotate (S
6). Further, since the driving force is transmitted to the registration roller driving gear 39 through the third driving gear 43, the lower registration roller 26b also starts to rotate and the upper registration roller 26a follows the lower registration roller 26b. Rotate.

After that, when the elapsed time from the generation of the copy start signal reaches T ₂ (sec) (S7), the solenoid 3
One pulse is input to 5 (S8), and the solenoid 35 is momentarily turned on. As a result, the locked state of the spring clutch 34 is released, and the spring clutch 3
4 are connected (S9), and the driving force from the drive unit 57 is transmitted by the transmission gear 68, the input gear 66, the cam drive gear 6
4, cam coupling coupling 69, and coupling 5
6 and the cam shaft 44 makes a half rotation (S1).
0). As a result, the cams 50 and 50 and the plate 51 rotate, and accordingly, the transfer roller 27 rises (S
11) The transfer of the toner image onto the paper 15 which is pressed against the transfer belt 12 and is conveyed by the upper and lower registration rollers 26a and 26b is started (S12).

When the elapsed time from the generation of the copy start signal reaches T ₃ (sec) (S13), one pulse is input to the solenoid 35 again (S14) and the electromagnetic clutch 65 is turned off (S13). S15). As a result, the rotation of the transfer roller 27 is stopped (S16), and the solenoid 35 is momentarily turned on, so that the engagement state with the spring clutch 34 is released, and the cam shaft 44 and the cam 50 are separated by half. Spinning plate 51
With the rotation of the transfer roller 27, the transfer roller 27 descends (S17), and is again separated from the transfer belt 12.

The elapsed time T ₃ (sec) from the generation of the copy start signal is such that the trailing edge of the paper 15 is the transfer roller 27.
Immediately after passing through the press contact portion between the transfer belt 12 and the transfer belt 12, the transfer roller 27 stops rotating and descends in accordance with the length of the paper 15 previously determined by the paper length detecting means 49. It was done. In addition, the transfer roller 2
Elapsed time T from the generation of the copy start signal indicating the timing of the rotation start of No. 7 and the rising start of the transfer roller 27
Similarly to T ₃ (sec), ₁ (sec) and T ₂ (sec) are also set according to the length of the paper to be copied.

On the other hand, the transfer belt 12 cleans the toner remaining on the transfer belt 12 without being transferred to the sheet 15 by the cleaner 1.
After being removed by 4, the rotation is stopped after a predetermined time. After the transfer process is completed, the paper 15 on which the toner image is transferred is fixed to the fixing device 30 by the conveyance belt 29.
And the toner image is heated and fixed between the fixing rollers 31 and 31 of the fixing device 30 and then the discharge rollers 32 and 32.
Is discharged outside the machine.

As described above, in the transfer roller device 24 of this embodiment, the idle shaft 33 for rotating the transfer roller 27 and the cam shaft 44 for moving the transfer roller 27 up and down are driven to rotate. Gears 64 and 6, respectively
6, drive transmission shaft 63/67, coupling coupling 60/6
9 and the like, and the rotation of the transfer roller 27 is controlled individually by the electromagnetic clutch 65, the solenoid 35, the spring clutch 34, and the like. And can be independently controlled.

Immediately after the rear end of the paper 15 to which the toner image is transferred passes through the pressure contact portion between the transfer roller 27 and the transfer belt 12, the rotation of the transfer roller 27 is stopped and the transfer roller 27 is lowered. Therefore, the rotation of the transfer roller 27, which is constantly in pressure contact with the cleaning blade 59, can be stopped except during the transfer operation. As a result, it is possible to prevent the expensive transfer roller 27 and the cleaning blade 59 from being worn, prolong the life of both, and prevent a transfer failure or a cleaning failure and obtain a good copy image.

[Embodiment 2] Next, another embodiment of the present invention will be described with reference to FIGS. 1, 2, 9, and 10. For convenience of explanation, members having the same functions as the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 2, the transfer roller device of this embodiment is provided in a copying machine similar to that of the first embodiment.
As shown in FIG. 5, the rotational drive of the transfer roller 27 and the vertical movement of the transfer roller 27 are independently controlled by the same configuration as that of the first embodiment. Then, after the rear end of the paper 15 passes through the pressure contact portion between the transfer roller 27 and the transfer belt 12, the transfer roller 27 is lowered to move the transfer belt 12
The rotation of the transfer roller 27 is stopped after a predetermined time has elapsed after the transfer roller 27 is separated.

The operation of the transfer roller 27 during the copying operation will be described below with reference to the flowchart of FIG. 9 and the timing chart of FIG. In this embodiment, after the paper size is set and the length of the paper is determined, the transfer roller is started to rotate by the control of the electromagnetic clutch 65, the solenoid 35, etc. The steps of (S21 to S32) are performed until
Since it is similar to the first embodiment, the description thereof is omitted.

After the start of transfer, when a predetermined time corresponding to the length of the paper 15 has elapsed and the elapsed time from the generation of the copy start signal reaches T ₃ (sec) (S33), the solenoid 35
One pulse is input to the transfer roller 27 (S34), the spring clutch 34 is connected, and the transfer roller 27 separates from the transfer belt 12 and descends (S35). Then, when a predetermined time further elapses and the elapsed time from the generation of the copy start signal reaches T ₄ (sec) (S36), the electromagnetic clutch 37 is turned off (S37), and the transfer roller 27 is rotated. It is stopped (S38).

That is, in this embodiment, the transfer roller 27
Similarly to the first embodiment, the lowering of the transfer roller 27 is performed immediately after the trailing edge of the paper 15 has passed the pressure contact portion between the transfer belt 12 and the transfer roller 27. It is supposed to be done after the time has passed.

By the way, when the transfer roller 27 is lowered and stopped substantially at the same time, the transfer belt 12 is delayed when the descending operation of the transfer roller 27 is delayed for some reason.
Therefore, the pressure contact time between the transfer roller 27 and the transfer roller 27 is extended. At this time, since the transfer belt 12 needs to be cleaned by the cleaner 14 to remove the residual toner, the transfer belt 12 continues to rotate, but the transfer roller 27 stops rotating. If the transfer belt 12 and the transfer roller 27 are brought into pressure contact with each other in such a state, scratches or the like may occur on both the transfer belt 12 and the transfer roller 27. Further, when the above-described scratches are generated on the transfer belt 12 and the transfer roller 27, the surface smoothness is lost, resulting in poor cleaning and poor transfer performance, and it is difficult to obtain a good copy image. Occurs.

Therefore, as in the copying machine according to the first embodiment, in the transfer roller device of the present embodiment which is configured to individually control the rotation and the vertical movement of the transfer roller, the transfer roller 27 is used. The timing to stop the rotation of
By delaying the lowering timing than the lowering timing, even if the lowering operation of the transfer roller 27 is delayed, the continuously rotating transfer belt 27 is pressed against the continuously rotating transfer belt 12.

Therefore, there is no possibility that the transfer roller 27 and the transfer belt 12 will be scratched, and good surface smoothness can be maintained.
It is possible to prevent deterioration of transfer performance and obtain a good copy image. Since the rotation of the transfer roller 27 is stopped only slightly later than the descending timing, the abrasion of the transfer roller 27 and the cleaning blade for removing the toner on the transfer roller 27 is prevented as in the first embodiment. It is also possible to obtain the effect of preventing them and prolonging their lives.

[Embodiment 3] Next, still another embodiment of the present invention will be described with reference to FIGS. 11 to 13. For convenience of explanation, members having the same functions as the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

The transfer roller device according to this embodiment is shown in FIG.
As shown in, the transfer roller drive gear 38 is provided only at the front end portion of the transfer roller 27 when the insertion direction of the transfer roller device 71 into the copying machine main body is the front side. In addition, the second drive gear 3 that meshes with the transfer roller drive gear 38
7 is also provided only on the front end side of the idle shaft 33 to which the driving force from the drive unit provided on the copying machine main body side is transmitted.

Other than the above, the structure of the transfer roller device 71 and the gear for transmitting the driving force are the same as those of the transfer roller device according to the first embodiment, and the transfer roller device 71 of the present embodiment is provided. Other configurations of the copying machine are the same as those in the first embodiment. Further, the rotation and vertical movement of the transfer roller 27 are also performed at the same timing as that of the transfer roller device in the first embodiment.

As shown in FIG.
As shown in, a one-way clutch (drive transmission switching means) 38a for transmitting the driving force from the drive unit is built in the transfer roller shaft 27a. Therefore, when the second driving gear 37 is rotated in the C direction by transmitting the driving force from the driving unit, the transfer roller driving gear 38 meshing with the second driving gear 37 is rotated in the D direction, and the one-way clutch 38a is rotated. Rotates in the D direction.

The one-way clutch 38a can transmit the driving force to the transfer roller shaft 27a only when the one-way clutch 38a rotates in the D direction.
When rotated in the direction, the transfer roller 27 also rotates in the direction D. As a result, the toner image is transferred onto the sheet at the pressure contact portion between the transfer belt 12 and the transfer roller 27.

On the other hand, the second drive gear 37 stops rotating,
When the transfer roller drive gear 38 stops, the built-in one-way clutch 38a also stops.
When 7 is pressed against the transfer belt 12, the transfer roller 2 is driven by the rotation of the transfer belt 12 in the E direction.
7 rotates in the D direction. That is, the transfer roller shaft 27a
Since the rotation direction of is the transmission direction of the driving force in the one-way clutch 38a, the transfer roller 27 can be rotated even when the one-way clutch 38a is stopped.

In the transfer roller device of the first and second embodiments, the transfer roller drive gears 38, 38 are provided at both ends of the transfer roller 27.
A pair of second drive gears 37, 37 meshing with 38 was also provided on the idle shaft 33 (see FIG. 1), but in the case of the present embodiment, the transmission of the drive force via the transfer roller drive gear 38. Since it is necessary to rotate the transfer roller 27 after releasing the above, the drive gears 37 and 38 are provided only on one side of the transfer roller 27 and the idle shaft 33.

By the way, the rear end of the sheet 15 is the transfer belt 1.
When passing through the pressure contact portion between the transfer roller 27 and the transfer roller 27, normally,
Here, the transfer roller 27 is separated from the transfer belt 12 and descends, and the rotation of the transfer roller 27 is controlled to stop. However, if the lowering operation of the transfer roller 27 is delayed for some reason, the pressure contact state between the transfer belt 12 and the transfer roller 27 is continued. Here, when the rotation of the transfer roller is stopped as in the first embodiment,
The transfer belt 12 that is pressed against the surface of the transfer belt 12 continues to rotate for cleaning, so that the transfer belt 12 and the transfer roller 27 are damaged as described in the second embodiment.

However, in this embodiment, since the one-way clutch 38a is built in the transfer roller drive gear 38, the transfer roller 27 can be rotated by being driven by the transfer belt 12. Therefore, even if the transfer roller 27 is delayed in descending after the transfer due to an erroneous operation, the transfer roller 27 and the transfer belt 12 are pressed against each other while continuing to rotate, so that the life of both can be extended. Therefore, it is possible to provide a good copy image stably for a long period of time.

Further, the transfer roller 27 is the transfer belt 1
When it is separated from the transfer roller 27, the rotation of the transfer roller 27 is stopped, so that the cleaning blade pressed against the transfer roller 27 and the transfer roller 2 as in the first embodiment.
It is possible to prevent abrasion of No. 7, prolong the life of both, and improve transfer performance.

[0071]

As described above, in the transfer roller device according to the first aspect of the present invention, after the trailing end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming member, the separating / contacting means is driven to perform the transfer. Separation and contact control means for separating the roller from the image forming body, and cut off the transmission of the rotational driving force from the driving means to the transmitting means after the rear end of the transfer material has passed the pressure contact portion between the transfer roller and the image forming body. The rotation control means for stopping the rotation of the transfer roller is provided.

Therefore, it is possible to reduce wear of the transfer roller and, for example, the cleaning blade pressed against the transfer roller, and prolong the life of the transfer roller. Therefore, it is possible to obtain a stable image for a long period of time. Produce an effect.

Further, as described above, the transfer roller device according to the second aspect of the invention transfers the transfer material by driving the separating / contacting means after the trailing end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body. The separation / contact control unit that separates the roller from the image forming body, and the transfer of the rotational driving force from the driving unit to the transmission unit is blocked after a predetermined time has elapsed from the separation operation of the transfer roller, so that the transfer roller is rotated. The rotation control means for stopping is provided.

Therefore, even if a malfunction occurs in which the transfer roller is not separated from the image forming body, the transfer roller is pressed against the rotating image forming body while continuing to rotate. Further, the surface smoothness of the image forming body can be maintained, the life of both can be extended, and stable images can be obtained for a long period of time.

Further, by setting the timing for stopping the rotation of the transfer roller to be slightly delayed from the separating operation of the transfer roller, the cleaning blade pressed against the transfer roller is brought into contact with the transfer roller as in the invention according to the first aspect. It is possible to prolong the life of the sheet and also to improve the transfer performance.

Further, in the transfer roller device according to the third aspect of the present invention, when the rotational driving force is transmitted from the transmitting means as described above, the rotational driving force causes the transfer roller to rotate, while the transfer roller causes the image to be transferred. When the rotational force of the image forming body is not transmitted and the rotational drive force is not transmitted from the transmitting means, the driving force transmission switching means is provided to rotate the transfer roller by following the rotation of the image forming body.

Therefore, even if a malfunction occurs in which the transfer roller is not separated from the image forming body and only its rotation is stopped, the transfer roller rotates following the image forming body. The life of the formed body can be extended and a stable image can be obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a configuration of a transfer roller device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of a copying machine including the transfer roller device shown in FIG.

FIG. 3 is a schematic diagram showing a state where the transfer roller is separated from the transfer belt in the transfer roller device shown in FIG.

FIG. 4 is a schematic diagram showing a state in which the transfer roller is raised and brought into contact with the transfer belt in the transfer roller device shown in FIG.

5 is a schematic diagram showing a state in which the transfer roller further rises and is pressed against the transfer belt in the transfer roller device shown in FIG.

6 is a block diagram showing a configuration of a control system included in the copying machine shown in FIG.

FIG. 7 is a flowchart showing an operation at the time of performing transfer in the transfer roller device shown in FIG.

8 is a timing chart showing the timing of starting each operation shown in FIG.

FIG. 9 is a flowchart showing an operation at the time of performing transfer in a transfer roller device according to another embodiment of the present invention.

10 is a timing chart showing the timing of starting each operation shown in FIG.

FIG. 11 is a partially cutaway perspective view showing the structure of a transfer roller device according to still another embodiment of the present invention.

FIG. 12 is a schematic diagram showing a state where the transfer roller in the transfer roller device shown in FIG. 11 is rotated by the transmission of the driving force from the one-way clutch.

13 is a schematic diagram showing a state in which the transfer roller is driven by the transfer belt and is rotating in the transfer roller device shown in FIG.

FIG. 14 is a perspective view showing a conventional transfer roller device.

[Explanation of symbols]

 12 transfer belt (image forming body) 15 paper (transfer material) 24 transfer roller device 27 transfer roller 34 spring clutch (separation / contact means) 35 solenoid (separation / contact control means) 33 idle shaft (transmission means) 37 second drive gear ( Transmission means) 38 Transfer roller drive gear (transmission means) 38a One-way clutch (driving force transmission switching means) 44 Cam shaft (separation / contact means) 50 Cam (separation / contact means) 51 Plate (separation / contact means) 53 Controller (rotation control Means, separation / contact control means) 54 first drive gear (transmission means) 55 gear with coupling (transmission means) 57 drive unit (drive means) 59 cleaning blade 60 roller drive coupling coupling (transmission means) 65 electromagnetic clutch ( Rotation control means) 71 Transfer roller device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Masuda 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (3)

[Claims] 1. A transfer material is sandwiched between a pressure contact portion of an image forming body and a transfer roller, and an image on the image forming body is transferred to the transfer material while the transfer material is being sent while rotating the transfer roller and the image forming body. At the same time, the transfer roller is rotationally driven by the rotational drive force from the drive means being transmitted through the transmission means, and the transfer roller is provided so as to be capable of being brought into contact with and separated from the image forming body by the contacting and contacting means. In the roller device, after the trailing edge of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body, the separating / contacting means is driven to separate the transfer roller from the image forming body; Rotation control means for stopping the rotation of the transfer roller by blocking the transmission of the rotational driving force from the driving means to the transmission means after the end passes through the pressure contact portion between the transfer roller and the image forming body. Characteristic transfer roller device. 2. A transfer material is sandwiched between a pressure contact portion of the image forming body and the transfer roller, and the image on the image forming body is transferred onto the transfer material while the transfer material is being sent while rotating the transfer roller and the image forming body. At the same time, the transfer roller is rotationally driven by the rotational drive force from the drive means being transmitted through the transmission means, and the transfer roller is provided so as to be capable of being brought into contact with and separated from the image forming body by the contacting and contacting means. In the roller device, after the trailing end of the transfer material passes through the pressure contact portion between the transfer roller and the image forming body, the separating / contacting means is driven to separate the transfer roller from the image forming body, and the separation of the transfer roller. And a rotation control means for stopping the rotation of the transfer roller by interrupting the transmission of the rotational driving force from the driving means to the transmission means after a predetermined time has elapsed from the operation. apparatus. 3. A transfer material is sandwiched between a pressure contact portion of the image forming body and the transfer roller, and the image on the image forming body is transferred onto the transfer material while the transfer material is being sent while rotating the transfer roller and the image forming body. At the same time, the transfer roller is rotationally driven by the rotational drive force from the drive means being transmitted through the transmission means, and the transfer roller is provided so as to be capable of being brought into contact with and separated from the image forming body by the contacting and contacting means. In the roller device, when the rotation driving force is transmitted from the transmission means, the transfer roller is rotated by the rotation driving force, while the transfer roller is pressed against the image forming body and the rotation driving force is not transmitted from the transmission means. Is a transfer roller device, characterized in that it is provided with a driving force transmission switching means for rotating the transfer roller by following the rotation of the image forming body.