JP2556691B2 - Transfer device - Google Patents

Description

The present invention relates to a transfer device applicable to an image forming apparatus that obtains multiple images using electrophotography.

(Prior Art) Generally, when a multicolor image is obtained using electrophotography, a photosensitive drum for forming each color image, a developing device, and an exposure device, and each color image are multi-transferred onto the same transfer material. Therefore, a transfer device is required.

By the way, as the transfer device, a gripping means for gripping the leading end of the transfer material is formed by forming a cylindrical body from two circular rings having the same outer diameter and a coupling member that couples these circular rings at a part on the generatrix. Is provided on the connecting member, and a transfer material supporting member that surrounds the outer peripheral portion without the connecting member is provided over both of the rings, and a transfer drum that rotates in synchronization with the rotation of the photosensitive drum is usually put into practical use.

Then, while the transfer drum is in contact with the photosensitive drum, an image on the photosensitive drum is transferred onto the transfer material in a multiple transfer manner by a transfer charger provided inside the transfer drum. Further, although the leading end of the transfer material is gripped by the gripping means provided on the connecting member, the other portion is supported by the transfer material supporting member provided on the transfer drum. Usually, a polyester film or the like is used as the transfer material supporting member.

However, when performing multiple transfer, it is required that the transfer material is completely in contact with the photosensitive drum at the transfer position. Therefore, it is possible to ensure that the transfer material support member is the same as or slightly larger than the outer diameter of the transfer drum over the entire area and that the transfer material support member is directly pressed from the inside of the transfer drum to ensure the contact of the transfer material with the photosensitive drum. A member having flexibility is usually used. The contact assurance member is provided near the shield plate of the transfer charger or the charging line of the charger.

(Problems to be solved by the invention) However, in such a conventional example, when the contact guarantee member is directly provided on the transfer charger, it is very difficult to operate when the transfer charger is attached to or detached from the transfer drum, There is a problem that the contact guarantee member is easily scratched and the original function is lost if the contact guarantee member is used while being scratched. In addition, when a contact assurance member other than the charger is provided, there is no problem in terms of operability, but when the transfer material support member is replaced, the tip of the contact assurance member projects to the outer periphery of the transfer drum, so it is extremely difficult. There is a problem that it is difficult to replace, and even if it can be replaced, it is not guaranteed that the transfer material supporting member is accurately positioned on the outer periphery of the transfer drum.

Therefore, the present invention has been made to solve the above-mentioned problems of the conventional example, and an object of the present invention is to greatly improve the operability of the transfer charger and to provide a transfer device that does not cause transfer defects. To provide.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a transfer material supporting member that supports and rotates a transfer material, and a transfer material supporting member provided inside the transfer material supporting member are provided. A charger for transferring the toner image on the image carrier to the transfer material supported on the transfer material support material;
In the transfer device having the above-mentioned structure, the charger is divided into a charger main body which is attachable to and detachable from the inside of the transfer material supporting member, and a shield plate having a flexible member in the transfer material supporting member. However, when the charger main body is mounted inside the transfer material support member, the position of the tip of the flexible member when the transfer material support member is not present is the outer circumference of the transfer material support member. The transfer material supporting member is pressed by the flexible member so that the transfer material is brought into contact with the image carrier so that the charging device main body is removed from the inside of the transfer material supporting member so as to be located outside the proper position. The flexible member is separated from the inner periphery of the transfer material supporting member during the operation.

(Operation) In the present invention having the above configuration, when the charger main body is mounted inside the transfer material supporting member, the tip end position of the flexible member when the transfer material supporting member is not present is the transfer material supporting member. Since the outer periphery of the image carrier is located outside the position where it should be and the transfer material support member is pressed by the flexible member to bring the transfer material into contact with the image carrier, the toner image on the image carrier is reliably transferred. To be done. On the other hand, when the charger main body is removed from the inside of the transfer material support member, the flexible member is separated from the inner periphery of the transfer material support member. Even if it is replaced, it can be carried out without any trouble, and the original function is not impaired without damaging the flexible member.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 3 shows a multicolor image forming apparatus to which the present invention is applied, which uses electrophotography.

In the figure, reference numeral 1 denotes a photosensitive drum which constitutes an image carrier, and rotates in the direction of arrow 2. Around the photosensitive drum 1, a charging device 12, a developing unit support 13, a transfer drum 20 which is a transfer material support, and a cleaning device 27 are arranged. Laser optical systems 10 and 11 form an image on the drum 1 from the color-separated image information signal. 10 is a polygon mirror, and 11 is a laser reflection mirror. The developing unit support 13 includes yellow Y, magenta M,
It supports developing units 131, 132, 133, and 134 of the same type using cyan C and black BK developers.

When an image of a specific color is formed on the drum 1, the developing unit 131, 132, 133, or 134 of that color is set on the drum 1.
When an image is formed adjacent to, and an image of a color different from that is formed, the developing unit of a desired color is adjacent to the drum 1 by rotating in the direction of arrow 135.

Reference numeral 15 is a cassette for accommodating the transfer material 14 (usually plain paper is used). The transfer material 14 in the cassette 15 is fed from the cassette 15 by the paper feed roller 16, passes through the first registration roller pair 17 and the second registration roller pair 18, and is fed to the paper feed guide 19. The transfer material sent is the first
(2) Timing is taken by the registration rollers 17 and 18, and the tip end is gripped by the gripper 201 on the transfer drum 20 as a cylindrical body. The transferred transfer material is an adsorption charger.
23, passing between the squeezing rollers 22, and sucked and held by the suction sheet 202 as a transfer material supporting member on the transfer drum 20 over the entire area. An image of the adsorbed transfer material is transferred onto the drum 1 by the transfer charger 24. The transfer process is repeated for each color, and when the transfer is completed, the gripper opens and the separation claw 28 guides the transfer unit 29. The transfer material guided to the transport unit 29 passes through the fixing roller pairs 30 and 31 to be fixed, and is placed on the tray 32. Drum 1 after transfer process
The image remaining on the top is cleaned by the cleaning device 27, and the drum is prepared for the next image formation. Reference numerals 25 and 21 are cams for opening and closing the gripper on the transfer drum.

On the other hand, FIG. 1 is a block diagram of the transfer charger in this embodiment. The transfer charger 24 includes a charger main body 240 composed of an L-shaped shield plate 241 and a wire 243, and a flexible member 24.
A shield plate 2 provided with 6 at its tip and swingable about an axis 244 provided parallel to the axis 201 of the transfer drum 20.
Divided into 45. The charger body 240 is the transfer drum 20.
Since it is movable in the axial direction of the inner support member 242, and further in the axial direction of the transfer drum 20, it can be detached from the transfer drum 20. On the other hand, the shield plate 245 is always provided inside the transfer drum 20. Shield plate 245 has stopper 247
Is provided and is locked when the shield plate 245 is rotated clockwise.

When the charger main body 240 is mounted on the transfer drum 20, the corner portion 241a of the L-shaped shield plate 241 contacts the shield plate 245 to position the shield plate 245. At this time, the flexible member 246 is the adsorption sheet 2 made of polyester film or the like.
When there is no 02, the position is the broken line in FIG. 1, while when there is a suction sheet 202, as shown by the solid line, the suction sheet 2
The suction sheet 202 is directly contacted with 02 to press the suction sheet 202 so that the slack of the suction sheet 202 does not occur at the contact portion (image transfer position) between the photosensitive drum 1 and the transfer drum 20. That is, it means that the occurrence of transfer failure is prevented. In this state, the tip of the flexible member 246 projects outward from the outer periphery of the transfer drum 20 by a.

On the other hand, FIG. 2 shows the charger main body from the state shown in FIG.
The state where 240 is removed from the transfer drum 20 is shown, and the position of the stopper 247 of the shield plate 245 is regulated by a not-shown locking portion. At this time, the tip of the flexible member 246 is located on the inner circumference side of the outer circumference of the transfer drum 20 by b. Therefore, even if the suction sheet 202 is converted in this state, since the flexible member 246 does not project from the outer periphery of the transfer drum 20, the suction sheet 202 can be replaced without any trouble. In addition, since the flexible member 246 is unlikely to be scratched during replacement, the original function of the flexible member is not impaired.

(Effect of the Invention) The transfer device according to the present invention has the above-described configuration and operation. When applied to a transfer device that performs multiple transfer, image transfer can always be performed normally, and a flexible member can be used. Since it can be used without being damaged, it has the effects of prolonging the service life and simplifying the operation when replacing the transfer material supporting member.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an embodiment of a transfer device according to the present invention, FIG. 2 is a schematic view of a main part of the same embodiment with a charger main body removed, and FIG. FIG. 3 is an overall configuration diagram of a multicolor image forming apparatus to which is applied. Explanation of code 1 …… Photosensitive drum (image carrier) 20 …… Transfer drum (cylindrical body) 24 …… Transfer charger 202 …… Suction sheet (transfer material support member) 240 …… Charger body, 245 …… Shield Plate 246 ... Flexible member

Claims (1)

(57) [Claims] 1. A transfer material support member that supports and rotates a transfer material, and a transfer material that is provided inside the transfer material support member and supports a toner image on an image carrier on the transfer material support member. And a charger that transfers the charger to the inside of the transfer material supporting member, and a flexible member in the transfer material supporting member. When the charger main body is mounted inside the transfer material support member, the position of the tip of the flexible member in the absence of the transfer material support member is the transfer plate. The transfer member support member is pressed by the flexible member to bring the transfer material into contact with the image carrier so that the outer periphery of the material support member is outside the position where it should be. When removed from the inside of the support member, A transfer device which is characterized in that to separate the flexible member from peripheral transfer material supporting member.