JPS5810766A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent the phenomenon of transfer failure of a transferred paper and the pollution due to a toner, by setting the volume resistance of a transfer material guide member to >=10<5>OMEGAcm when the transfer paper is guided to a developed image formed on a photosensitive drum by the transfer material guide member. CONSTITUTION:A developed image 2 is formed on a photosensitive drum 1 (image carrier) by latent image forming and developed image forming means. A transfer corona discharger 3 is arranged, and metallic transfer material lower and upper guide members 4 and 5 are provided, and a transfer paper is put on the upper guide member 5, and the photosensitive drum 1 is rotated in the direction of an arrow to transfer the developed image by transfer corona discharge. For the purpose of preventing the toner from pollution due to generation of a high voltage, transfer material upper and lower guide members 4 and 5 are provided with a resistance material layer 6 where carbon is dispersed in polyethylene to have a volume resistivity of 10<8>OMEGAcm, and these members 4 and 5 are grounded through the resistance. Thus, the transfer current is prevented, and the carriability of the transferred paper is improved, and the phenomenon of transfer failure and the pollution due to the toner are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device, and more particularly to a transfer device K that enables good transfer without staining the transfer material.

2. Description of the Related Art Conventionally, a transfer device has been widely used that transfers a transfer material to developed images formed on a g1a carrier such as an electrophotographic photoreceptor by guiding the transfer material using a transfer guide member and applying a transfer voltage.

However, in such a transfer device that applies a transfer voltage, the transfer current leaks through the transfer material guide member at high temperatures, resulting in a phenomenon of undesired transfer in which good transfer is not achieved. As a countermeasure against this problem, there are 511 techniques listed below.

#11 is for electrically floating the transfer material guide member.

When this method is used, even if the transferred member absorbs moisture at high temperatures, transfer omission will not occur, but the transfer electric current iSl flows into the transfer guide member and charges the transfer guide member, which causes floating toner and toner on the latent image carrier. Attract and accumulate. This toner comes into contact with the transfer material and causes stains on the image. In addition, when the temperature is high, friction between the transfer material and the transfer material guide member causes charging, which causes stains.

The second method is to apply a bias voltage to the transfer material guide member to prevent transfer current from leaking.This method can also prevent transfer omissions in the same way as the previous method, but requires a separate source. This makes the device complicated. Moreover, since voltage is applied, safety measures for operator maintenance are required.
This also makes the device even more complicated.

lI5 is for grounding the transfer material guide member via a resistor.

m easily accumulates and toner stains are likely to occur.

Furthermore, if the surface of the transfer material guide member is made of metal, the conveyance of the transfer material may deteriorate at high temperatures.

The present invention addresses the above points! The present invention provides a transfer device capable of achieving good transfer performance.

The device of the present invention is a transfer device in which a transfer material guide member guides a transfer material to the developed images formed on a co-carrier to perform transfer, and the transfer material guide member prevents leakage of transfer current that causes transfer omission. l! have a material with a volume resistivity sufficient to absorb the floating developer and not cause charge build-up that would create a potential to adsorb floating developer. #Mold O In the above configuration of the present invention, it is a preferable configuration that the substance having the volume resistivity is disposed on the transfer material contacting surface of the transfer material guide member.

Further, in the above structure of the present invention, the volume resistance of the substance is 1
To 0'? , 1 or more is a preferable configuration. Furthermore, in the wjJ configuration of the present invention, it is a preferable table configuration that the volume resistivity of the substance is 101 g·1 or less.

Hereinafter, details of the present invention will be explained using specific examples with reference to the drawings.

FIG. 1 is a side view of a specific example transfer device according to the present invention.

1 is a photosensitive drum that is rotated once in the direction of the arrow by a driving means (not shown).

2, #me forming means (not shown) and m are placed on the receptor dots.
05, which are good gL images formed by the ta means, is a discharge device for transferring stiffness, 4 is a transfer material lower guide member made of metal, and 5 is a transfer material upper guide member also made of metal.

Reference numeral 6 denotes a resistive material layer provided on the surface of the lower guide member for the transfer material, and in the illustrated example, the material is dispersed in high-molecular polyethylene and has a volume resistance of 108 g. This enables good transfer to the transfer material 7 even in a high humidity environment (for example, 8011RH).

Incidentally, the resistive material layer 6 is made of polymeric Botethylene (volume resistivity 10"421cm or more) in which Karn is not dispersed.
If you cannot use the low 1111 boundary (e.g. 2591R1()
At this point, the transfer material lower guide member 4 is charged due to friction between the transfer material lower guide member 4 and the transfer paper 7. According to experiments, when the distance between the sensory drum 1 and the transfer material lower guide member 4 is 1.2 -, the potential of the transfer material lower guide member reaches 11000 V or more. However, when the voltage exceeds -500V, toner adheres to the tip of the guide member and the back side of the image edge of the next transfer paper becomes dirty.
I got 1.

In this case, toner of negative polarity was used, but it is thought that the toner that received a positive KIF charge after being exposed to the transfer plate was attached to the maid.

In addition, at high temperatures, the current from the transfer corner discharger 3 is transferred to the transfer material lower guide member 4K via the transfer paper 7 with low resistance.
If the guide is charged up to +1000 V or more and the guide becomes charged, the voltage is +70.
It is clear that at 0v or higher, the guide gets dirty and the back of the 1m ring becomes dirty. On the other hand, as in the device according to the embodiment of the present invention described above,
A layer of a predetermined resistive material such as polymeric polyethylene dispersed in 90% is provided on the surface of the guide member 4, and the voltage is -500 V at low humidity.
Even at high temperatures, the potential of the guide could be suppressed to within +500V, and no staining of the guide occurred.

In order to prevent the transfer material guide member from becoming dirty, the resistive material layer should be configured so that even if charge is accumulated, the potential is suppressed to -500V to +70OV (in practice, the volume resistance is It is sufficient if it is 1011·1 or less.

And preferably it is 10Ω·0 or less. On the other hand, in order to prevent transfer failure, it is inconvenient to make it smaller than 10''Ω·l in practice.And preferably it is 106Ω·1 or more. FIG. 2 is a side view for explaining. Members common to those in FIG. 1 are indicated by the same numbers. In FIG. This promotes ensuring the layering of the transfer current and prevents the developer toner from adhering to the surface of the transfer material upper guide member 5 even after long-term use.

Therefore, it is possible to prevent the developer from spilling onto the transfer material surface.

Incidentally, as the above-mentioned resistive material, a material having a large number of teeth may be selected in consideration of the frictional force with the transfer material.

Furthermore, even if the material is essentially an insulating material, it may be mixed with a conductive material or a surfactant to give it an appropriate volume resistance as described above.

In addition, in the example N, the surface of the metallic guide member is coated with a resistive material layer, but it goes without saying that the guide member may be formed of a resistive material having appropriate strength. .

[Brief explanation of drawings]

FIG. 1 is a side view of a specific example transfer device based on the present invention, and FIG. 2 is a side view of a modified example based on the present invention. In the figure, 1: Elemental drum (midair carrier), 2: Developers, 3
: transfer corona discharger, 4.5: transfer material guide member, 6: resistive material layer. Applicant Canon Co., Ltd.

Claims (1)

[Scope of Claims] 0) Transfer material guide ll# to be formed on the image carrier and to be developed.
In a transfer device that guides a transfer material and performs transfer, the transfer material guide member has a charge accumulation that is sufficient to prevent transfer current leakage that would cause transfer omission, and that generates a potential that creates several layers of floating am agent. The presence of a substance with a resistive force in the volume 11 that does not cause the above-mentioned volume resistivity is defined as a 41 mold. In material welding, Ml
411 that the volume resistivity of the substance is 10" or more.
1. Transfer device (4) Claims 1, 2 or JII3
In the invention described in paragraph 1, the volume resistivity of the substance is 10"#
Transfer device characterized by Q or less