JPH04174880A - Image forming device - Google Patents

Abstract

PURPOSE:To make it unnecessary to provide a separation roller to separate easily a copying paper from an image holding body and to simplify the device by forming adhesive members on the peripheral surfaces of the ends of a copying roller to copy a toner image to a copying paper. CONSTITUTION:A copying roller 2 consists of a conductive rubber, its peripheral surface 20 is abutted to the peripheral surface 10 of an image holding body 1, and circular adhesive members 20a are formed on both sides of the peripheral surface 20. The adhesive members 20a catch a copying paper which passed between the roller 2 and the holding body 1 and a toner image has been copied on the surface, and separate it from the holding body 1. And by the conveying force following the rotation of the roller 2 and the holding body 1, the copying paper is fed to a copying paper guide. Since the copying paper can be caught and separated from the holding body by the adhesive members formed on the copying roller in such a way, a separation roller is not necessary to provide, and the device can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to image forming apparatuses such as electrostatic copying machines and laser beam printers.

<Prior art> Conventionally, a transfer charger generates a corona discharge from behind the transfer paper to apply an electric charge to the transfer paper, and after transferring a toner image to the transfer paper using this electric charge, an adhesive is applied to the surface. An image forming apparatus is known in which a transfer paper is separated from an image carrier by a separation roller (
(See Japanese Patent Application Laid-Open No. 149979/1983).

However, the above-mentioned image forming apparatus has a problem in that harmful ozone is generated by corona discharge, and uneven transfer occurs in the formed image due to uneven discharge due to dirt on the discharge wire. .

Furthermore, since the transfer paper is charged to a high potential, there are problems such as a discharge phenomenon occurring and the transfer paper becoming difficult to separate from the image carrier.

Furthermore, two members, a transfer charger and a separation roller, are required, which makes the device complicated.

Therefore, in place of the transfer charger, a transfer roller to which a bias voltage is applied is provided, and with the bias voltage applied to the second transfer roller, the transfer roller performs the following operations.
2. Description of the Related Art Image forming apparatuses have come into use in which a transfer material such as copy paper is brought into pressure contact with the surface of an image carrier so that a toner image formed on the surface is transferred to the transfer material.

With the above configuration, there is no need for a transfer charger, so there is no risk of generating harmful ozone, and since the transfer is in close contact, there is an advantage that only blurring occurs in the image.

<Problems to be Solved by the Invention> However, even in the image forming apparatus using the above transfer roller, two members, the transfer roller and the separation roller, are still required, and each roller is synchronized with the rotation of the image carrier. However, it has not been possible to solve the problem that the device becomes complicated, such as requiring a mechanism to rotate the device.

The present invention has been made in view of the above circumstances, and
The purpose is to provide an image forming device with a simpler structure, which does not require a transfer charger that generates harmful ozone or causes uneven transfer, or a separation roller that complicates the mechanism of the device. .

Means for Solving the Problems> To solve the above problems, an image forming apparatus of the present invention includes an image carrier on which a toner image is formed, and a bias voltage applied to transfer the toner image to a transfer paper. The present invention is characterized in that it includes a conductive transfer roller that transfers images to the image carrier, and an adhesive portion is formed on the peripheral surface of the end portion of the transfer roller to assist in separating the transfer paper from the image carrier.

According to another aspect of the present invention, a conductive adhesive portion is formed on at least a portion of the circumferential surface of the transfer roller to assist in separating the transfer paper from the image carrier. An image forming apparatus is provided.

Effect> According to the image forming apparatus of the present invention having the above configuration, the transfer paper can be reliably separated from the image carrier by the adhesive portion provided on the transfer roller that transfers the toner image onto the transfer paper. . Furthermore, if the adhesive part is made conductive, a bias voltage can be applied to this adhesive part as well, making it possible to transfer the entire surface, and it is not necessary to limit the location of the adhesive part to the vicinity of the end of the transfer roller. For example, by adding an adhesive part to the center of the transfer roller, or by making almost the entire surface of the transfer roller an adhesive part, separation of the transfer paper from the image carrier can be made more reliable. There are advantages.

<Embodiment> An image forming apparatus of the present invention will be described below with reference to drawings showing an electrostatic copying machine as an embodiment.

As shown in FIG. 4, the electrostatic copying machine of this embodiment includes a charging roller 4 around a drum-shaped image carrier 1 for charging the image carrier 1, and a charging roller 4 indicated by a white arrow in the figure. As shown, an optical system (not shown) that exposes the surface of the image carrier 1, a developing device 6 that develops the electrostatic latent image formed on the surface of the image carrier 1 by exposure into a toner image, and It includes a transfer roller 2 that transfers the toner image formed on the image carrier 1 onto a transfer paper T such as copy paper, and a cleaner 8 that removes the toner remaining on the image carrier 1.

Then, the charging roller 4 charges the surface of the image carrier 1 rotating at a constant speed.
The electrostatic latent image is uniformly charged by the camera, exposed to light by the optical system to form an electrostatic latent image, and the electrostatic latent image is visualized as a toner image by the developing device 6. This toner image is then transferred onto the transfer paper guide 7a. The toner is transferred onto the surface of the transferred transfer paper T by the transfer roller 2, and after the transfer, the toner remaining on the surface of the image carrier 1 is removed by the cleaner 8 and cleaned, thereby completing one cycle of image formation. do. Further, the transfer paper T peeled off from the image carrier 1 is transferred to the transfer paper guide 7b.
The toner image is guided to a fixing device (not shown) through the toner image, where the toner image is fixed, and then discharged from the device.

The charging roller 4 and transfer roller 2 are connected to a single power source 9.

The transfer roller 2 is entirely made of a conductive material such as conductive rubber, and as shown in FIG.
The image carrier 1 is disposed below the image carrier 1 so as to be in contact with the peripheral surface 10 of the image carrier 1 . At both ends of the circumferential surface 20, annular adhesive portions 20a, 20a are formed.

As shown in FIG. 2, the adhesive portion 20a is formed by filling a circumferential groove 21 formed at the end of the transfer roller 2 with an adhesive material. As the adhesive material, conventionally known adhesive materials such as paste-like rubber glue can be used. In addition, a conductivity imparting agent such as silver powder is blended into the adhesive material, and the adhesive part 2
It is also possible to impart conductivity to 0a, in which case a bias charge is also applied to the adhesive parts 20a, 20a, making it possible to transfer the entire surface.

The adhesive portion 208.20a functions to pass between the transfer roller 2 and the image carrier 1, capture the transfer paper T on which the toner image has been transferred, and separate it from the image carrier 1.

Then, the transfer paper T separated from the image carrier 1 is supplied to the above-mentioned transfer paper guide 7b by the conveying force accompanying the rotation of the transfer roller 2 and the image carrier 1.

Note that the adhesive portions 20a, 20a increase the frictional force between the image carrier 1 and the transfer roller 2, so the adhesive portions 20a, 20a protrude outside the transfer paper conveyance area at both ends of the peripheral surface 20. By forming the transfer roller 2, the transfer roller 2 can be rotated in synchronization with the image carrier 1 without providing a special mechanism for driving the transfer roller, and the mechanism for driving the transfer roller can be omitted. , it is also possible to further simplify the configuration of the device.

In addition to the adhesive parts 20a, 20a, an adhesive part 20b can also be formed at the center of the peripheral surface 20 of the transfer roller 2, as shown by the dashed line in FIG. Since the central adhesive portion 20b corresponds to the image forming area of the image carrier 1, it must be made of an adhesive material with conductivity so as not to interfere with the transfer of the toner image onto the transfer paper T. There is.

In addition to the adhesive parts 20a, 20a, the peripheral surface 2 of the transfer roller 2
If the adhesive portion 20b is also provided at the center of the image carrier 0, the force for capturing the transfer paper T increases, so that the transfer paper T can be separated from the image carrier 1 more reliably.

According to the image forming apparatus of this embodiment, which is composed of the above-mentioned parts, the toner image on the surface of the image carrier 1 is transferred onto the transfer paper T by the transfer roller 2. There is no risk of generating ozone or causing uneven transfer. Further, since the transfer paper T is captured by the adhesive portions 20a, 20a formed on the transfer roller 2 and separated from the drum 1, there is no need to provide a separation roller, and the structure of the apparatus can be simplified. .

In addition, as mentioned above, when forming an adhesive part with an adhesive material imparted with conductivity, as in the modification shown in FIG. It is also possible to form a wide adhesive portion 20c. In the transfer roller 2 in which the wide adhesive portion 20c is formed in this way,
The force that captures the transfer paper T further increases, so the transfer paper T
can be separated from the image carrier 1 more reliably.

The configuration of the image forming apparatus of the present invention is not limited to the above embodiments and modifications.

The arrangement, width, etc. of the adhesive portion can be changed as appropriate depending on the conveyance state of the transfer paper in the image forming apparatus, the size of the transfer paper used, etc. For example, in an image forming apparatus that feeds transfer papers of different sizes to the image carrier 1 with their edges aligned, adhesive sticks only to the edge of the transfer roller's peripheral surface on the side where the edges of each transfer paper are aligned. Transfer paper of different sizes may be placed on the image carrier 1 with their center lines aligned.
In an image forming apparatus that supplies transfer rollers, the adhesive portion may be formed only at the center of the circumferential surface of the transfer roller.

In the embodiment shown in FIG. 1, the adhesive part 20a is formed by filling the groove 21 formed in the transfer roller 2 with an adhesive material, but the adhesive part is formed by applying a thin layer of adhesive material to the surface of the transfer roller. Alternatively, the entire portion of the transfer roller corresponding to the adhesive portion may be formed of adhesive rubber or the like.

As the image carrier 1, in addition to a drum-like one, various shapes such as a belt-like one can be used.

The configuration of the present invention can be applied not only to the electrostatic copying machine described above but also to other image forming apparatuses such as a laser printer.

- In addition, various design changes can be made without changing the gist of the present invention.

<Effects of the Invention> The image forming apparatus of the present invention is configured as described above, and since the toner image on the surface of the image bearing member is transferred onto the transfer paper by the transfer ports, it can be used as a transfer charger. To,
There is no risk of generating harmful ozone or uneven transfer, and since the transfer paper is captured and separated from the drum by the adhesive portion formed on the transfer row, there is no need to provide a separation roller. Therefore, according to the present invention, the structure of the device can be made simpler. Also,
When the adhesive part is made conductive, a bias voltage can be applied to this adhesive part as well, so it is possible to transfer the entire surface, and there is no need to limit the location of the adhesive part to the vicinity of the end of the transfer roller. For example, by adding an adhesive part to the center of the transfer roller, or by making almost the entire surface of the transfer roller an adhesive part, it is possible to separate the transfer paper from the image carrier more reliably. be.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an image carrier and a transfer roller as essential parts of an electrostatic copying machine as an embodiment of the image forming apparatus of the present invention, and FIG. 2 is a partial cross-sectional view of the transfer roller.
FIG. 3 is a perspective view showing a modification of the transfer roller, and FIG. 4 is a schematic diagram showing the structure of the electrostatic copying machine of the embodiment. 1... Image 2 carrier, 2... Transfer roller, 20...
Surrounding surface, 20a, 20b, 20c - adhesive part

Claims (1)

[Claims] 1. Equipped with an image carrier on which a toner image is formed, and a conductive transfer roller to which a bias voltage is applied to transfer the toner image to a transfer paper. An image forming apparatus characterized in that an adhesive portion is formed to assist in separating the transfer paper from the image carrier. 2. An image carrier having a toner image formed on its surface, and a conductive transfer roller to which a bias voltage is applied to transfer the toner image to a transfer paper, and at least a portion of the circumferential surface of the transfer roller. An image forming apparatus characterized in that a conductive adhesive portion is formed to assist in separating the transfer paper from the image carrier.