JPS62141585A - Electrostatic copying machine - Google Patents

Abstract

PURPOSE:To prevent suspended toner from moving onto a paper guide sheet by providing the front end part of the paper guide sheet in contact with or closely to a paper guide plate on a transfer part side. CONSTITUTION:The paper guide sheet 11 is cut almost to the paper width of maximum size to be fed and adhered on the paper guide plate 7 with an adhesive. A transfer material 8 sent out of the paper feed timing roller 5 of a paper feeding part moves along the surface of the paper guide sheet 11 to reach its front end part. The front end part of the paper guide sheet which contacts the paper guide plate 6 or is positioned nearby is spread by the transfer material 8, which moves between the spread parts. The transfer material, on the other hand, is passed while pressed against the paper guide plate 6 by the paper guide sheet 1, so the transfer material 8 is therefore pressed against an image carrier 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic copying apparatus such as an electrophotographic copying machine that obtains copies by corona transfer.

BACKGROUND ART In recent years, in electrostatic copying devices such as electrophotographic copying machines, the most common method is to transfer a toner image developed on an image bearing member such as a photoreceptor onto a transfer material by corona transfer. used in

An example of a conventional electrostatic copying apparatus will be described below with reference to the drawings.

FIG. 3 shows a conventional electrostatic copying apparatus.

In FIG. 3, a toner image 3 is visualized by a developing device 2 on an image carrier 1 such as a photosensitive drum. In order to increase the transfer efficiency, the electrostatic image on the image carrier 1 is removed or weakened in advance by a pre-transfer exposure lamp 4, and the transfer material 8, such as paper, fed by a paper feed timing roller 6 is placed on a paper guide/plate 6 and 7 and enters the corona transfer section. The toner image 3 is transferred onto the transfer material 8 by the corona emitted from the wire 9 of the transfer charger, and the transfer material 8 is separated from the image carrier 1 by the AC corona emitted from the wire 1o of the separation charger. .

Problems to be Solved by the Invention However, with the above-described configuration, the toner image on the image carrier 1 has a tendency to cause the toner around the image to scatter on the transfer material 8 during transfer, resulting in a decrease in image quality.

Furthermore, the surface of the guide plate 70 is easily contaminated with toner.

Since the transfer material 8 passes through contact with the transfer material 8, there is an inconvenience that the back surface of the transfer material 8 gets dirty.

The reason why the image quality deteriorates due to transfer is that corona is emitted from the transfer wire 9 before the transfer material 8 is fully in contact with the image carrier 1, and as a result, the toner image 3 is scattered onto the transfer material 8. This is to move on. In order to prevent this, it is possible to set the paper guide plate high, but if you do this, for example, if you are feeding thick paper such as postcard paper.

Since the paper is too stiff, it tends to get jammed at the part where it enters the image carrier 1, resulting in a narrow selection range of paper that can be passed through one paper.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a transfer section that transfers the toner image visualized on the carrier onto the transfer material by applying a corona discharge from the back side of the transfer material. The transfer material fed from the paper feed section is guided into the transfer section by a fixed paper guide plate and a flexible and elastic paper guide sheet, and this paper guide plate and paper guide foot In this case, the leading end of the paper guide sheet is provided in contact with or close to the paper guide plate on the transfer unit side.

Function: Due to the above-mentioned structure of the present invention, the transfer material passes through the transfer section while being constantly pressed against the image carrier, so that a clear image without scattering of the toner image on the transfer material can be obtained. (9) Since the transfer material is guided by the flexible and elastic sheet, the range of paper that can be passed through is expanded from thin paper to thick paper.

Furthermore, since the leading edge of the paper guide sheet is in contact with or close to the paper guide plate on the transfer unit side, floating toner is prevented from entering onto the paper guide sheet, causing the back side of the transfer material to become dirty. The inconvenience will disappear.

EXAMPLE Hereinafter, an electrostatic copying apparatus according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of the main part of an electrostatic copying apparatus according to an embodiment of the present invention. Note that the same components as in the conventional example are given the same reference numerals.

In this embodiment, the paper guide plate 7gIc paper guide sheet 11
The configuration is shown in Fig. 2.

In Fig. 2, numeral 7 indicates a paper guide plate, and numeral 11 indicates a flexible and elastic paper guide sheet.
I used a thick one.

The paper guide sheet 11 was cut approximately to match the width of the largest size of paper to be passed, and was adhered to the single paper guide plate 7 with an adhesive. The operation of the electrostatic copying apparatus equipped with this paper guide sheet 11 will be described below.

The transfer material 8 sent out from the paper feed timing roller 6 of the paper feed section reaches the leading end of the paper guide sheet 110 along the surface thereof. The leading edge of the paper guide sheet that is in contact with or close to the paper guide plate 6 is pushed out by the transfer material 8,
The transfer material 8 passes between them. On the other hand, since the transfer material passes through being pressed against the paper guide plate 6 by the paper guide sheet 11, the transfer material 8 is pressed against the image carrier 1 as a result. Therefore, a good image without scattering marks can be obtained. As a transfer material for this device,
Weighing 409/ltf, 60,76.80゜eo, 1st
Although 1000 sheets of sy/- paper, OHP 7 ilm, label paper, etc. were passed through and copied, there was no problem of paper jam due to the provision of the one-sheet guide sheet 11. Also.

With any of the transfer materials, there was almost no deterioration in image quality due to toner image scattering, and clear copies with no back stains were obtained.

However, the surface of the paper guide plate 7 and the paper guide sheet 11
There was toner on the back side of the paper. This is due to the friction between the paper guide sheet 11 and the transfer material 8.
It is thought that the toner particles were charged and that the floating toner was attracted by the action of static electricity. Therefore, a paper guide sheet with gold, aluminum, vanadium, etc. deposited on the surface of a polymer film, and a carbon conductive paint coated on top of the polymer film, was used.
When a sheet with a conductive surface or a stainless steel sheet plate with a thickness of 1 μm was made conductive at least on the surface that contacts the paper, the adhesion of toner near the paper guide sheet 11 was significantly reduced. Furthermore, no paper feeding problems or deterioration in image quality were observed due to the change to conductive sheets.

Effects of the Invention As described above, the electrostatic copying apparatus of the present invention is provided with a transfer section that transfers the toner image visualized on the image carrier onto the transfer material by applying corona discharge from the back side of the transfer material, and The transfer material fed from the paper section is guided into the transfer section by a fixed paper guide plate and a flexible and elastic paper guide sheet. This is because the leading edge of the paper guide sheet is placed in contact with or close to the paper guide plate on the transfer unit side.

It is possible to obtain high-quality copies with clear toner images without scattering and without stains on the back side.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of an electrostatic copying apparatus according to an embodiment of the present invention, FIG. WJ2 is a perspective view of the paper guide plate of this embodiment, and FIG. 3 is a sectional view of the main parts of a conventional electrostatic copying apparatus. It is. 1... Image carrier, 2... Developing device, 6.
7...Paper guide plate, 8...Transfer material, 1
1...Paper guide sheet. Name of agent: Patent attorney Toshio Nakao and one other person6.
7---NNT ID, δ---SOFTWARE Figure 1
tr---mvη°I donut Figure 2 I

Claims (2)

[Claims] (1) A transfer section is provided that transfers the toner image visualized on the image carrier to the transfer material by applying corona discharge from the back side of the transfer material, and the transfer material fed from the paper feeding section is transferred to the paper guide plate. introduced into the transfer section by a paper guide sheet,
An electrostatic copying apparatus characterized in that the paper guide sheet is disposed on the paper guide plate so that a leading end of the paper guide sheet contacts or approaches the paper guide plate on the side of the transfer section. (2) The electrostatic copying apparatus according to claim 1, wherein at least the surface of the paper guide sheet facing the paper guide plate is electrically conductive.