JPS6397977A - Transfer fixing device - Google Patents

Abstract

PURPOSE:To prevent heat from being conducted to an image holder and to prevent the image holder from being filmed with toner by providing a cooling means which contacts an intermediate transfer body in the middle of a path extending from a secondary transfer part to a primary transfer part. CONSTITUTION:A finned roller 26 and auxiliary rollers 27A and 27B are arranged in contact with the intermediate transfer body 21 between a primary transfer part 25 where a backup roller 23 and a heat roller face each other and a primary transfer part 24 where a pressure roller 22 and the image holder face each other. The roller 26 is formed of a metallic material with good heat conductivity such as Al and cooling fins 28 made of Al metallic plates extend from the center part of a hollow cylindrical member to the periphery. Further, the rollers 27A and 27B are formed of metallic materials such as Al. The intermediate transfer body 21 which is heated by the heat roller of the secondary transfer part 25 contacts the surfaces of the rollers 27A, 26, and 27B and its heat is radiated before it moves to the primary transfer part 24, so that the transfer body is cooled to temperature at which no thermal influence is exerted upon the image holder.

Description

[Detailed Description of the Invention] [Summary] A transfer fixing device in an electrophotographic apparatus, which transfers a toner image formed on an image carrier such as a photosensitive drum to a recording medium such as recording paper via an intermediate transfer body. In a device that transfers and fixes the image to the image carrier, in order to prevent the heat for thermal fixing in the secondary transfer section of the transfer fixing device from transferring to the image carrier via the intermediate transfer member, A cooling means is installed on the path leading to the transfer section so as to come into contact with the intermediate transfer body.

(Industrial Application Field) The present invention relates to recording devices such as electrophotography and electrostatic recording,
In particular, the present invention relates to a transfer fixing device in the recording apparatus.

After uniformly charging a photosensitive drum with a photoreceptor film formed on its surface such as selenium (Se), the drum is irradiated with a laser beam or the like to form an electrostatic latent image, and toner is applied to this electrostatic latent image. An electrophotographic apparatus is well known in which a toner image is formed by adhering to a toner image, and then the toner image is transferred and recorded onto a recording paper or the like.

Such a transfer fixing device is desired to transfer a toner image formed on an image carrier such as a photoreceptor drum to a recording medium without causing disturbance.

[Conventional technology]

Conventionally, when transferring such a toner image to a recording paper, the recording paper is placed on top of the toner image, and a corona discharge or bias voltage is applied from the back side of the recording paper to apply an electric charge to the recording paper, thereby reducing the electrostatic charge. Generally speaking, a method was adopted in which the toner image was transferred to recording paper.

However, with the method of electrostatically transferring toner images onto recording paper,
There is a problem in that charge disturbance occurs during transfer and fine dust etc. adhere to the periphery of the transferred toner image.

Therefore, as a method to eliminate such defects, for example, Japanese Patent Publication No. 46-41679, Japanese Patent Publication No. 48-22763,
In Japanese Patent Publication No. 57-20632, etc., a method is disclosed in which a toner image is once transferred by being brought into pressure contact with an intermediate transfer member, and then the toner image transferred to this intermediate transfer member is further transferred and fixed by thermocompression bonding to a recording paper. provided.

According to such a method, unlike the case where a toner image is electrostatically transferred to a recording paper, a toner image can be transferred to a recording medium without disturbance.

A conventional electrophotographic apparatus using such an intermediate transfer member is shown in FIG.

As shown in FIG. 4, after the image carrier 1 is uniformly charged by a charger 2, an electrostatic latent image is formed by an exposure device 3.

The image carrier 1 rotates in the direction of the arrow, and the toner in the developing device 4 adheres to the electrostatic latent image formed on the image carrier 1 and is visualized to form a toner image 13a. .

The toner image 13a is transferred to the intermediate transfer member 6 at a position where the intermediate transfer member 6 is pressed against the image support member 1 by the pressing force of a pressing roller that rotates while facing and in contact with the image support member 1.

Furthermore, after the toner image 13a is transferred to the intermediate transfer body 6,
The remaining toner in contact with the image carrier 1 is removed by a cleaner 5.
cleaned by.

Furthermore, the toner image 13b pressed onto the intermediate transfer member 6 is thermally transferred and fixed onto the recording weight 2 by a heating roller 10 having a built-in heater 1) and a backup roller 8.

[Problem that the invention seeks to solve]

In the conventional transfer fixing method using such an intermediate transfer body, the pressure roller 7 and the image carrier 1 are placed facing each other in order to enable transfer fixation without disturbing the toner image and improve transfer efficiency. In the primary transfer section 14, pressure transfer is performed, and in the secondary transfer section 15, where the heating roller 10 and the backup roller 8 are installed facing each other, thermal fixing is performed. By performing thermal fixing, it is possible to achieve 100% transfer efficiency from the intermediate transfer member 6 to the recording member 12.

However, since the intermediate transfer body 6 is also heated during thermal fixing, if heat dissipation is insufficient when the intermediate transfer body 6 returns from the secondary transfer unit 15 to the primary transfer unit 14, There is a problem that heat is transferred from the intermediate transfer member 6 to the image carrier 1, and as a result, there is a problem that the performance of the image carrier 1 is deteriorated.

Furthermore, since the toner image 13a formed on the image carrier 1 comes into contact with the high-temperature intermediate transfer member 6 at the primary transfer section 14, a phenomenon of toner filming occurs in which the toner softens and adheres to the image carrier 1. There was a problem.

[Means for solving problems]

The transfer fixing device of the present invention is provided with a cooling means that contacts the intermediate transfer body and cools the intermediate transfer body in the middle of the path from the secondary transfer unit to the primary transfer unit.

[Effect]

The transfer fixing device of the present invention is provided with a cooling means that contacts the intermediate transfer body and cools the intermediate transfer body in the middle of the path from the secondary transfer unit to the primary transfer unit. By removing heat from the transfer body, heat is prevented from being transferred to the image carrier, and the phenomenon of toner filming on the image carrier is prevented.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the transfer fixing device of the present invention.

As shown in the figure, the transfer fixing device of the present invention includes an intermediate transfer body 2
1, the bank up roller 23 and the heating roller 10 shown in FIG. 4 are opposed to each other, and the pressing roller 22 and the image carrier 1 shown in FIG. A finned roller 26 and auxiliary rollers 27A and 27B are arranged between the opposing primary transfer sections 24.

This finned roller 26 may be provided in place of the tension roller 16 shown in FIG. 4, or may be provided adjacently.

The auxiliary rollers 278 and 27B are provided to increase the contact area between the finned roller 26 and the intermediate transfer body 21.

The intermediate transfer body 21 is formed by coating a transfer layer of silicone rubber, fluororubber, etc. on a base material made of metal such as aluminum (A/) or polymer resin with excellent heat resistance such as polyimide in the form of a film. has been done.

As shown in the sectional view of FIG. 2, this finned roller 26 has an outer diameter of 6 (bm) and an inner diameter of 56 fl, and is made of a metal material with good thermal conductivity such as Aff. A cooling fin 28 made of a beta metal plate extends from the center of the hollow cylindrical member toward the periphery of the cylindrical member. It is formed.

The diameter of the finned roller 26, its length in the direction perpendicular to the paper surface, the wall thickness of the cooling fin 28, the cooling fin 28
The number of sheets depends on the contact time between the intermediate transfer body 21 and the heating roller 10 shown in FIG. determined by the dimensions of Also, the thermal characteristics of the intermediate transfer body 21 or the image carrier 1 of FIG.
It is determined by parameters such as the allowable temperature, the contact area between the intermediate transfer body 21 and the finned roller 26, and the contact time.

Further, the auxiliary rollers 27A and 27B are formed by injection molding a metal material with high thermal conductivity, such as ^l, into a cylindrical shape.

If such a transfer fixing device is used, the intermediate transfer body 21 heated by the heating roller in the secondary transfer section 25 comes into contact with the surfaces of the auxiliary roller 27A, the finned roller 26, and the auxiliary roller 27B, and is transferred to the primary transfer section 24. During the movement, heat is radiated and the image carrier is cooled to a temperature that does not have a thermal effect.

FIG. 3 shows another embodiment of the invention.

As shown in the figure, in the embodiment of the wood brush 2, a cooling fan 33 for cooling the inside of the finned roller 31 is attached to the rotating shaft 32 of the finned roller 31 used in the previous embodiment.

In this way, the cooling air generated by the cooling fan 33 further cools the cooling fins inside the finned roller 31, so that the cooling effect of the intermediate transfer member can be further enhanced.

〔Effect of the invention〕

As described above, according to the method of the present invention, heat is sufficiently radiated from the intermediate transfer body by the finned roller on the path from the secondary transfer unit to the primary transfer unit, so that the image carrier is heated. It is possible to eliminate the phenomenon of toner deterioration caused by toner particles, and furthermore, it is possible to eliminate the phenomenon of toner filming on the image holding member, and it is possible to obtain a transfer fixing device that can perform good transfer to the recording member.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the main parts of the transfer fixing device of the present invention, FIG. 2 is a cross-sectional view of the finned roller of the present invention, and FIG. 3 is a cross-sectional view of a second embodiment of the finned roller of the present invention. Figure 4 shows a schematic diagram of a conventional electrophotographic device. In the figure, 21 is an intermediate transfer body, 22 is a pressure roller, 23 is a backup roller, 24 is a primary transfer section, 25 is a secondary transfer section, 2
6.31 is a finned roller, 27A and 27B are auxiliary rollers, 28 is a cooling fin, 32 is a rotating shaft, and 33 is a cooling fan. Li Liangming η transfer fixing device 4 perspective closed Fig. 1 7F* EI4/174 > attached) F=force 1iffl Fig. 2

Claims (3)

[Claims] (1) Transfer fixing in which the toner image formed on the image carrier is primarily transferred to the intermediate transfer body in the primary transfer section, and then the toner image attached to the intermediate transfer body is secondarily transferred to the recording medium in the secondary transfer section In the apparatus, a cooling means (26) that contacts the intermediate transfer body (21) and cools the intermediate transfer body is provided in the middle of the path from the secondary transfer unit (25) to the primary transfer unit (24). A transfer fixing device characterized by being provided with a transfer fixing device. (2) The cooling means (26) has cooling fins (
28) The transfer fixing device according to claim 1, wherein the transfer fixing device is a hollow cylindrical roller. (3) A heat dissipation fan (33
) The transfer fixing device according to claim 1 or 2, characterized in that the transfer fixing device is provided with: