JPH0413170A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent occurrence of transfer failure of inside blank even in a transfer of a part with a large quantity of toner adhered especially to an edge part of a fine line or a solid image by setting a pressurizing force which pressurizes a transfer material to a photosensitive body in a specified range with a pressurizing means. CONSTITUTION:In each transfer position the transfer material P is transferred; by a transfer charger 12BK at a photosensitive body 3BK, by a transfer charger 12Y at a photosensitive body 3Y, by a transfer charger 12M at a photosensitive body 12M, and by a transfer charger 12 C at a photosensitive body 3C. Then, the pressure of the pressurizing member 11 which pressurizes the transfer material P to the photosensitive body is selected to be 2.0g/cm<2> to 20g/cm<2>. Therefore, the transfer material P which is carried by a carrying device 10 has a toner image of the photosensitive body 3 transferred to it under the effect of the transfer charger 12 in a state where it is pressurized to the photosensitive body with the selected pressure force by the pressurizing member 11. Thus, even in the transferring of the parts where there is a large quantity of toner adhered as the edge parts of the fine line or the solid image, the occurrence of the transfer failure with the inside blank can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transfer device for an image forming apparatus such as a copying machine, a printer, or a facsimile.

[Prior art]

In an image forming apparatus such as a copying machine, especially in a full-color image forming apparatus in which a toner image on a double photoreceptor is superimposed and transferred onto a transfer material, the transfer material conveyed by a conveyor belt is pressed onto each photoreceptor by a pressing member such as a Mylar plate. It is known, for example, from Japanese Unexamined Patent Publication No. 62127770, etc.

In an image forming device that forms an image by transferring a toner image on a photoconductor to a transfer material, if the pressing force when the transfer material contacts the photoconductor is weak, the toner image will not be transferred sufficiently to the transfer material. , the image may become thinner, so conventionally, a pressing member was used to press the transfer material against the photoreceptor with as strong a force as possible. However, if the pressing force of the transfer material against the photoreceptor is too strong, the image quality may actually deteriorate. For example, in full-color copying, thin lines or edges of uneven images, especially areas with a large amount of toner adhesion, may be hollowed out. A defect occurs.

In order to prevent this phenomenon, it is possible to add hydrophobic silica to the toner to improve its fluidity, but the amount of silica added is limited due to filming on the photoreceptor and environmental fluctuations. Therefore, depending on the additive, a satisfactory solution cannot be obtained.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a transfer device that does not cause image defects.

[Means to solve the problem]

The present invention solves the above problem by bringing a transfer material conveyed by a conveyance device into contact with a photoconductor under the pressing action of a pressing means.
A transfer device for transferring an image on a photoreceptor to a transfer material using a transfer charger, characterized in that a pressing force for pressing the transfer material against the photoreceptor by the pressing means is set to 2 g/cm to 20 g/cm. The problem was solved with a device.

[Effect]

According to the present invention, the pressure of the pressing member that presses the transfer material against the photoreceptor is selected to be 2.0 g/C1 to 20 g/CI. The transfer material transported by the transport bag f is pressed against the photoreceptor by the pressing member with the selected pressure, and the toner image on the photoreceptor is transferred onto the transfer material under the action of the transfer charger.

〔Example〕

The details of the present invention will be explained based on embodiments shown in the drawings.

In FIG. 1 showing an example of an image forming apparatus using the present invention, an image of a document read by a reading device 1 is color-separated in an image forming section 2 onto photoreceptors 38K, 3Y, 3M, and 3C, respectively. The image is formed as an electrostatic latent image, and on the photoconductor 38, a developing device 48K develops a yellow toner, on the photoconductor 3Y, a developing device 4Y develops a yellow toner, and on a photoconductor 3M, a developing device 4M develops a magenta toner. The toner particles are then sequentially transferred onto the material P by the developing device 4C on the photoreceptor 3C.

At each transfer position, the transfer material P is pressed against the photoreceptor 3 by the pressing member 11, and the transfer material P is pressed against the photoreceptor 3 by the transfer charger 128K in the photoreceptor 3DK, by the transfer charger 12Y in the photoreceptor 3Y, and by the transfer charger 12M in the photoreceptor 3M. In the photoreceptor 3C, transfer charger 1
Transcribed by 2C.

The transfer material after the transfer is fixed by the fixing device 13 and discharged.

As shown in FIG. 2, the pressing member 11 can be formed of, for example, Mylar fixed to the casing 14 of the transfer charger 12. The pressing member 11 is the conveyor belt 10
By pressing , the conveyed transfer material is pressed against the photoreceptor 3 .

An experiment was conducted to determine the effect of changing the pressing force of the pressing member 11 on the transfer material on the transferred image quality, and the results shown in Table 1 below were obtained.

Table 1 In the table, ◯ indicates that the image quality is good with respect to the evaluation item, △ indicates that it is somewhat poor, and × indicates that it is poor.

From the results of this experiment, it was found that it is necessary to set the pressing force of the transfer material against the photoreceptor by the pressing member in the range of 2 to 20 g/ai in order to obtain good image quality.

The above results apply not only to full-color image formation in which multiple images are transferred one on top of the other, but also to i! It was found that this also applies to the case of monochromatic image formation such as four images.

〔effect〕

According to the present invention, it was possible to avoid transfer defects such as voids even in the transfer of fine lines and rough areas of solid images, particularly in areas with a large amount of toner adhesion, and a good transferred image was obtained.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram of an image forming apparatus according to the present invention, and FIG. 2 is an explanatory diagram of a pressing member.

Claims (1)

[Scope of Claims] A transfer device in which a transfer material conveyed by a conveyance device contacts a photoreceptor under the pressing action of a pressing means, and an image on the photoreceptor is transferred to the transfer material by a transfer charger, comprising: A transfer device characterized in that a pressing force for pressing a transfer material against a photoreceptor is set to 2 g/cm to 20 g/cm.