JPS6091364A - Image forming device - Google Patents

Abstract

PURPOSE:To transfer an image excellently and prevent the drop-out of transfer by providing a conveying means with a conductive material with high electric resistance which contacts a material to be transferred, and grounding this conductive material. CONSTITUTION:The conveying means 9 is provided between a paper feeder 6 and a photosensitive drum 1. The means 9 consists of a couple of register rollers 10 and 11 and a guide body 15 which faces them at an interval and guides a form P. The roller 10 consists of a core bar 12 and conductive rubber 13, and the core bar 12 is grounded 14. The roller 11 is made of metal and insulated electrically from a main body. When paper P is fed from the feeder 6, the paper is charged electrostatically by a feed roller 8, but it contacts the roller 10 in the middle of the conveyance to move charged on the paper P to the ground 14 through the roller 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus used, for example, as an electronic copying machine.

[Technical background of the invention and its problems]

Generally, an electronic copying machine is equipped with a paper feed device, and the stack of copy paper stored in the paper feed cassette is pressed against a rubber roller by the pressure of a spring, the rubber roller is rotated, and the paper is fed out by the frictional force, and the paper is fed into the cassette. The main method is to separate the sheets one by one using claws provided on the holder. In this case, the paper is often charged by the friction between paper and paper, rubber and paper, or metal and paper, and is sent out from the paper feeder in that state. An image is transferred to this sent paper by a transfer device, but the mainstream transfer device uses an electrostatic transfer method that applies a charge of opposite polarity to the toner to the back of the paper and attracts the toner from the photoreceptor. be. By the way, if the paper is already charged, if there is a charge of the same polarity as the toner on the top surface of the paper, the toner will concentrate there and form a black spot, and if there is a charge of the opposite polarity to the toner, it will repel and transfer. This causes a defective image.

Therefore, there is a method of grounding the part of the conveyance device in front of the transfer device that comes into contact with the paper to remove the electrical charge from the paper in advance. However, especially in high humidity, the electrical resistance of the paper decreases and There is a problem in that the generated charge escapes to ground, resulting in poor transfer. Furthermore, when an insulating material such as a plastic sheet is used as a transfer member, if the narrow surface becomes low in resistance due to moisture absorption or the like, the charge supplied from the transfer charger will escape to the ground, causing a similar problem.

The present invention has been made in view of the above-mentioned circumstances, and its object is to be able to transfer an image well even when the transfer material is in a state where the belt is bent, and to be able to transfer an image well even in high humidity conditions. It is also an object of the present invention to provide a single image forming device 4 that can prevent transfer defects.

[Summary of the invention]

In order to achieve the above object, the present invention provides a conveyance means for conveying a transfer material with a conductive material having high electrical resistance that comes into contact with the transfer material, and this conductive material is grounded.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention shown in FIGS. 1 and 2 will be described.
Explain with reference to.

In the figure, reference numeral I denotes a photoconductor drum (as an image carrier), and along the rotation direction of the photoconductor drum 1, there is a corona charger 2, a photoconductor 3, a transfer charger 4, etc. ,
A peel charger 5 is provided. Further, a paper feeding device 6 is provided diagonally below the photosensitive drum I, and this paper feeding device 6 includes a cassette 7 that accommodates F[] paper P, and paper r''fJf, P in this cassette Z. and a feeding roller 8 that takes out and feeds the sheet.A conveying means 9 is provided between the sheet feeding device 6 and the photosensitive drum I.This conveying means 9 It is constituted by a pair of registration rollers 1 o , z z , h and a guide body 15 , 15 facing away from each other and guiding the sheet P.

The registration roller 10 includes a core metal 12 and a core metal 12.
The core metal 12 is connected to a ground I4. Further, the registration roller II is made of metal and is electrically insulated from the main body (not shown).

During image formation, the surface of the photoreceptor drum 1 is uniformly charged by the corona charger 2, and an electrostatic layer image corresponding to the original is formed on the surface of the charged photoreceptor drum I by an exposure means (not shown). It is formed. This electrostatic latent image is developed by being supplied with developer in the developing device 3, and then sent to the transfer charger 4 side. On the other hand, at this time, the feeding roller 8 of the paper feeding device 6 is rotated and the sheets P in the cassette 7 are taken out one by one by frictional force. This taken out paper P is guided by the guide body 15.1.
5 and is sent to registration roller 10.11.
This registration roller 10. By the rotation of II, the photosensitive drum I is transported between the photosensitive drum I and the transfer charger 4 in a timely manner. The image on the photosensitive drum I is transferred by the action of the transported paper PKii copy charger 4.

Then, the paper P on which this l'1fjif image has been transferred is peeled off from the photosensitive drum I by the action of the peeling charger 5.
After being fixed for 1ε, the image is sent to a fixing device (not shown), where the image is fixed and then discharged.

By the way, during this image formation, when the paper P is fed from the paper feeding device 6, the paper P is charged by the friction of the feeding roller 8 as shown in FIG. 2.
By contacting the registration roller 10 during transport, the electric charge on the paper P is released to the ground 14 via the registration roller 10 because the registration roller 10 is made of the conductive rubber I3 as described above. It turns out.

Therefore, when transferring one image per surface, it is possible to transfer the image satisfactorily without being affected by the charge on the paper P.

In addition, even if the electrical resistance of paper P decreases in high humidity,
Since the registration roller 10 has a high electrical resistance of 10 to 10 8 Ω/(s2), the charge from the transfer charger 4 is not unlimitedly taken away by the ground I4, and a good transfer connection can be achieved.

Note that the present invention is not limited to the above embodiment,
As shown in FIG. 3, the surface of the lower registration roller 11 may be coated with a conductive mylar 21 having an electrical resistance of 10 to 10 Ω/(713"), and this may be connected to the ground 22. .

According to this, both the registration rollers 10 and 11 can be provided with a function of removing charges, and the effect of removing charges can be further enhanced.

Further, as shown in FIG. 4, conductive Mylar 3Z, 31 having an electrical resistance of 10 to 10 Ω/GB2 is attached to the tip of the guide body 15°15, and this is connected to the ground. 2
, 32. According to this implementation sequence, the charge on the paper P can be removed in two stages, and the snow removal effect is excellent. Note that the guide body 15.15 is insulated.

〔Effect of the invention〕

As explained above, in the present invention, since the conductive material is grounded in the conveyance means, even if the transferred material is charged, the electrical charge can be removed by the conductive material, and both images can be transferred well. Even if the electrical resistance of the transferred material decreases, since the conductive material has a high electrical resistance, the 'di charge from the transfer means will not escape to the ground indefinitely, and the transfer can be maintained well. It is something.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention,
The internal configuration of the glvVi copier, Figure 2 shows the
[An explanatory diagram showing state E, FIG. 3 is a side view showing a first alternative embodiment of this apology, and FIG. 4 is a side view showing a second alternative embodiment. 9... Conveyance means, P... Transferred material (paper), 1...
- 1 is a carrier (photosensitive drum), 4... transfer means (transfer charger), 13, 21.31... # electrical material (conductive rubber, 4-grade mylar). Applicant's representative Patent attorney Takeshi Suzue Syllable 2 Figure 3 Figure 4

Claims (1)

[Claims] (!) In a device in which an image on an image carrier is transferred by a transfer means to a transfer material conveyed by a conveyance means,
An image forming apparatus characterized in that the conveying means is provided with a conductive material of high electrical resistance that comes into contact with the transfer material, and this conductive material is grounded. (2) The conveying means includes a registration roller, and the registration roller is made of a conductive material.
ij Enclosure 1 Item 1 The image forming device described in Item 1. (3) The conveying means includes a guide body that guides the transferred material,
3. The image forming device according to claim 1, wherein the guide body is provided with a conductive material. (4) The image forming apparatus according to claim 1, 2 or 3, wherein the conductive material has an electrical resistance of 10 3 to 10 Ω/♂.