JPH0387877A - Transfer device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to transferring a toner image formed on an image bearing member in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus onto a flexible sheet. The present invention relates to a transfer device for transferring onto a held transfer material.

[Conventional technology]

Conventionally, many proposals have been made for transfer devices that transfer a toner image formed on an image carrier to a transfer material held on a dielectric sheet. In particular, in color image forming apparatuses that obtain color images by forming toner images of multiple colors on a photoreceptor drum, a multiple transfer method is effective because it is less likely to cause image disturbance during development. The above-mentioned transfer drum method, which is relatively easy to align, is effective and has been widely used.

Among these methods, there are several methods of holding the transfer material in a transfer material holding device, but recently the electrostatic adsorption method has been attracting attention because it has a degree of freedom in the number of sheets to be held and is easy to increase speed. In the electrostatic adsorption method, for example, corona discharge is generated by applying a voltage to an adsorption charger placed on the back of the dielectric sheet, and an adsorption charge is placed on the back of the dielectric sheet to create an electrostatic gap between the transfer material and the dielectric sheet. This is a method in which the transfer material is held on the transfer material holding device by generating an electric adsorption force.

At this time, in order to increase the efficiency of charge application to the back surface of the dielectric sheet, a conductive roller is placed on the opposite side of the adsorption charger across the dielectric sheet transfer material, and a bias voltage is applied to the conductive roller. Alternatively, methods such as grounding were considered. In addition, a corona regulating member made of an insulating elastic material is placed near the adsorption charger to reduce the gap between the dielectric sheet transfer material and the conductive roller, thereby further increasing the efficiency of charge injection into the transfer material. It was also structured.

In addition, as a transfer method, a corona transfer method is effective because it can cover a wide transfer area, and is known as
By making the side edges of the dielectric sheet attached to the transfer drum movable in the direction of rotation, as proposed in 2003, the transfer nip width is further widened and stable transfer is possible. In this system, even in the above-mentioned adsorption step, charge injection into the transfer material by the conductive roller provided as a counter electrode of the adsorption charger is also promoted.

[Problem that the invention is trying to solve]

However, as mentioned above, if the side edge of the transfer sheet is completely free, when the leading edge of the transfer material passes through the suction part, the corona regulating member creates a space between the dielectric sheet and the transfer material and between the transfer material and the conductive roller. A large gap was created, and conversely, charge injection into the transfer material was not effective at the leading edge of the transfer material, which often resulted in poor suction. In particular, in a transfer material holding device in which the front end of a dielectric sheet is fixed to a transfer drum, the amount of deformation when trying to hold the transfer material near the dielectric sheet is different between the transfer material and the dielectric sheet, and the above-mentioned problem arises. Such a phenomenon occurred noticeably.

[Purpose of the invention]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a transfer device that prevents deformation of a flexible member that supports a transfer material.

Another object of the present invention is to provide a transfer device that prevents failure of suction of a transfer material to a flexible member.

A further object of the present invention is to provide a transfer device that can perform stable and good transfer.

[Structure of the invention]

In order to achieve the above object, the present invention provides a transfer device having a transfer means for transferring a toner image on an image carrier onto a transfer material at a transfer position, including a flexible member supporting the transfer material; , a movable support means for supporting the flexible member in an overlapping manner, the part of the side portion of the flexible member other than the overlapping portion between the tip of the flexible member and the support means being fixedly fixed. The present invention is characterized in that it includes a support means for supporting the transfer material, and a suction means for suctioning and holding the transfer material on the flexible member.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 and FIG. 2 are a sectional view and a perspective view, respectively, showing an embodiment of the transfer device of the present invention.

A primary charger 2 uniformly charges an image carrier, that is, an electrophotographic photoreceptor drum l, which is rotatably supported on a shaft and rotates in the direction of the arrow, and image information is generated by an exposure means 3 comprising, for example, a laser beam exposure device. An electrostatic latent image is formed on the photosensitive drum l by irradiating a light image corresponding to the photosensitive drum l. The electrostatic latent image is developed as a toner image on the photosensitive drum 1 by the developing device 4.

On the other hand, the transfer material P is supplied by the registration roller 22 to the cylindrical transfer drum 10, which is a transfer material holding device, in synchronization with the image. The transfer material supporting device has a detailed structure as shown in FIG. In the figure, 51 is a dielectric sheet (hereinafter referred to as a transfer sheet) as a flexible member, 60 is an auxiliary ring 52, 53, and a stay S connecting the rings, which rotates while supporting the transfer sheet 51. It is a support means for the sheet 51, and the leading end of the transfer sheet 51 on the downstream side in the moving direction is superimposed on the stay S and fixed by a joint at the bottom of the superimposed part. Although the transfer material holding device 10 rotates in the direction of the arrow, the leading end of the transfer sheet 51 is fixed to the joint portion by a fixing screw 54. On the other hand, in this embodiment, the rear end of the transfer sheet 51 is supported by the stay S using a step screw 55, and a tension spring 56 is used to pull the rear end of the transfer sheet 51 in the direction of arrow a in FIG. maintains sexuality. Only the leading end of the side end portion of the transfer sheet 51 is fixed to the auxiliary ring 52, 53 by an adhesive member 57. Here, the portion where the transfer sheet 51 is fixed to the auxiliary rings 52 and 53 is at least a portion other than the overlapping portion of the leading edge of the transfer sheet 51 and the stay S with respect to the moving direction of the transfer drum 10, that is, a portion where the transfer sheet 51 is not supported. It is. For this reason, the transfer sheet has almost no degree of freedom at the leading end of the transfer sheet, and its movement is regulated, but the degree of freedom of the transfer sheet is large at the rear end of the transfer sheet. In FIG. 2, the transfer sheet 5
The transfer sheet 5 other than the overlapping portion between the leading end of the transfer sheet 1 and the support means 60
1 is fixed to the rings 52 and 53 of the support means 60; however, in addition to the adhesive portion 57 shown in FIG. Of course you can. Furthermore, in FIG. 2, supporting means 60 are provided at the ends of the transfer sheet in the longitudinal direction.
Although there are some parts that are not adhesively fixed to the transfer sheet, it may be completely adhesively fixed to the ends of the transfer sheet. Further, in the figure, 59 is a separating claw guide groove, and 58 is a separating roller guide groove.

The transfer material holding device 10 has a built-in adsorption corona charger 11 that applies an electric charge to the back surface of the transfer sheet, and a conductive roller 17 that has the same polarity and is grounded. is electrostatically attracted to the transfer sheet 51 by the action of . In the figure, 15 is the adsorption corona charger 11
This is a corona regulating member provided for the purpose of regulating corona discharge from the transfer sheet 51 and forming a nip between the transfer sheet 51 and the conductive roller 17, and is made of an insulating elastic body.

The transfer material P sent from the registration rollers 22 is brought into contact with the transfer sheet 51 at the suction section A. At this time, it is assumed that the leading edge of the transfer material P is placed near the fixed portion of the transfer sheet 51, that is, in a location where a portion of the leading edge overlaps the guide groove 59 in FIG. The transfer sheet 51 is deformed toward the conductive roller 17 by the corona regulating member 15 coming into contact with the transfer sheet 51 . The amount of deformation is determined by the fact that the leading edge of the transfer sheet 51 is attached to the auxiliary ring 52 by the adhesive member 57.
．． 53, there is less on the leading edge side of the transfer sheet 51. Therefore, the transfer material P is quickly adsorbed in a state close to the original curvature (circular) of the transfer material holding device 10 without being subjected to the curvature separation effect at the adsorption portion. After the adsorption of the tip ends, the corona regulating member 1 of the transfer sheet 51 is
Since the deformation caused by the transfer sheet 51 is large, the charge injection into the transfer material P by the conductive roller 17 is sufficiently performed, and a larger electrostatic attraction force is generated between the transfer sheet 51 and the transfer material P.

The transfer material P attracted to the transfer material support device 10 is conveyed to a transfer area where the photosensitive drum 1 and the transfer charger 12 are arranged and face each other, and the toner image on the photosensitive drum L is transferred. Ru. At this time, on the back surface of the dielectric sheet 51, a charge having a polarity opposite to that of the toner is placed by the transfer charger 12, but in the transfer device according to the present invention, most of the both ends of the transfer sheet 51 are free. Since it is at the end, it is possible to form a wide transfer nip between the transfer material P and the photosensitive drum 1, and therefore a good transferred image can be obtained.

The transfer material P that has completed the transfer process is transported to a separation area, and a separation process is performed. In this separation step, the separation claw 21 is connected to the transfer material P.
This is done mechanically by entering between the auxiliary rings 52 and 51 and the transfer sheet 51. At this time, the separation claws 21 are provided so as to come into contact with the peripheral surfaces of the auxiliary rings 52 and 53. As the guide roller 20 moves and falls into the separation claw guide roller entry groove 58, the separation claw 21 enters the separation claw guide groove 59, and transfers the transfer material P that has been placed in advance so as to slightly cover the separation claw guide groove 59. The structure is such that a separation claw is inserted into the lower part. At this time, for the purpose of eliminating static electricity on the back surface of the dielectric sheet and the surface of the transfer material (toner image surface), an internal static elimination charger 13 is provided at the opposing portion of the transfer material support device 10 and the transfer sheet 51, sandwiching the inside thereof. , corona discharge is performed by the external charger 14.

The transfer material P separated from the transfer material support device 10 as described above is transported to the fixing device 30 by the transport means 31, and the toner image is fixed onto the transfer material P.

On the other hand, after the residual toner on the surface of the photosensitive drum 1 is cleaned by a cleaning device 20, the photosensitive drum 1 is subjected to an image process again. Further, the surface of the transfer material sheet 51 is similarly cleaned by cleaning devices 18 and 19, and then subjected to the image processing again.

3 and 4 are a perspective view and a sectional view showing a second embodiment of the transfer device of the present invention, in which 61 is a suction port, 62 is a duct, 63 is an exhaust fan, and 64 is an exhaust fan controller. , 23 indicates a rotation axis of the transfer material supporting device.

In this embodiment, only when the transfer material P is attracted to the transfer material support device IO, the leading end of the transfer sheet 51 is moved to the auxiliary ring 5.
2. The purpose is to fix it to 53. This is because the adverse effect of the deformation of the leading end of the transfer sheet 51 is a problem only in suction, and in transfer, it is desirable that both sides of the transfer sheet be free ends.

When the transfer material P reaches the suction section, the exhaust fan controller 23 issues a signal to rotate the exhaust fan 64. Accordingly, the exhaust fan 64 operates, and a force is generated near the exhaust hole 61 that pulls the transfer sheet 51 toward the auxiliary rings 52 and 53, that is, toward the inside of the transfer drum IO. After the transfer material P is adsorbed by the transfer material holding device 10 and before reaching the transfer process, the exhaust fan controller 2
3 issues a signal to stop the exhaust fan 64.

Accordingly, the rotation of the exhaust fan 64 is stopped, and both ends of the transfer sheet 51 become free ends.

There are many possible applications of the method of controlling the degree of freedom at the leading end of the transfer sheet 51. For example, a magnetic material is provided at the leading end of the transfer sheet 51, and an electric coil is connected to the opposing part. Place an electromagnet with the current flowing through the coil as O
A similar effect can be expected by using a method of controlling by turning the switch OFF.

〔Effect of the invention〕

As explained above, according to the transfer device of the present invention, the flexible member carrying the transfer material is supported by being superimposed on the supporting means, and the overlapping portion between the tip of the flexible member and the supporting means is Since part of the side part of the flexible member other than the one shown in FIG. Ta.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a transfer device embodying the present invention, FIG. 2 is a perspective view illustrating one embodiment of the transfer device of the present invention, and FIG. 3 is a diagram illustrating another embodiment of the transfer device of the present invention. A perspective view for explanation, and FIG. 4 is a cross-sectional view of FIG. 3. 1: Photosensitive drum 2 primary charger 3: Image exposure 4: Developing device 5: Cleaning device 1O: Transfer material holding device 11: Adsorption charger 12: Transfer charger 15: Corona regulation member 16: Corona regulation member 17: Conductive roller 51: Transfer sheet 52, 53: Auxiliary ring 54: Fixing screw 55: Step screw 56: Spring 57: Adhesive member 60, : Holding means 61: Suction port 62: Suction duct 63: Suction fan 64: Exhaust fan 64 : Exhaust fan controller S: Stay procedure amendment (method) 1. Display of the case 1999 25344 Relationship with the person who amends the name of the invention transcription device case

Claims (2)

[Claims] (1) In a transfer device having a transfer means for transferring a toner image on an image carrier onto a transfer material at a transfer position, a flexible member supporting the transfer material and this flexible member are overlapped. a movable support means for supporting the transfer material, the support means fixedly supporting a part of the side portion of the flexible member other than the overlapping portion between the tip end of the flexible member and the support means; 1. A transfer device comprising a suction means for suctioning and supporting a flexible member. (2) The suction means includes an adsorption corona discharge means for applying an adsorption corona discharge from the back surface of the flexible member, which moves the transfer material onto the flexible member at the adsorption position; 2. The electroconductive member according to claim 1, further comprising a discharge regulating member that regulates a discharge area of the discharge, and a conductive member that is disposed so as to face the adsorption corona discharge means and be placed in contact with or close to the transfer material. transcription device.