JPH0247681A - Noncontact type heat fixing device - Google Patents

Abstract

PURPOSE:To convey a form which is being heated smoothly without staining the form and to enable heat fixation without any heating irregularity by arranging on-plate heaters on both sides of reverse of the form. CONSTITUTION:The form 9 which has a toner latent image, etc., formed on the top surface is pressed and conveyed into a wall by a conveyor roller 1a and then the form is conveyed on a feed belt 4 provided between belt rollers 17a and 17b. Further, when the form 9 conveyed on the belt 4 passes on a heater 7 fitted in the feed belt 4, radiant heat is applied to the reverse surface of the form 9 and then the form is discharged out of the wall by a conveyor roller 1b. Consequently, the staining of the form and heat fixation irregularity are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal fixing device for heating and thermally fusing a toner latent image formed on a sheet of paper, such as a copying machine.

C. Summary of the Invention] The present invention provides a structure of a thermal fixing device for heating and thermally fusing a toner latent image formed on a sheet of paper, such as a copying machine, by using a feeding belt and a plate-shaped heater, and The position is placed on the back side of the paper so that there is no contact, and radiant heating is used to eliminate uneven heating and fixing.

[Conventional technology]

Conventionally, as shown in FIG. 3, there is a contact type heat fixing device in which a heater 10 such as a halogen lamp is built into a hollow roller 11 to heat the paper, and an outer wall for blocking outside air as shown in FIG. 3 is used. A non-contact type heat fixing device is known which has a heater 13 and a heater 14 that heats the inside of the wall.

[Problem that the invention seeks to solve]

However, in the case of a contact-type heat fixing device, the toner latent image formed on the paper may adhere to the roller 11 and stain the paper, or depending on the type of toner, it may wrap around the roller 11 and cause a jam. Ta. In addition, in the case of a non-contact type heat fixing device, as shown in FIG. 3B, it is formed by an outer wall 13, a heater 14, a conveying roller 12, and a feeding means 15, and heats the inside of the wall to form a toner latent image. Since the surface is heated by radiation, the temperature of the latent image surface becomes significantly non-uniform due to uneven heat absorption efficiency due to the brightness and darkness of the latent image surface. This has resulted in drawbacks such as difficulty in uniformly fixing the entire paper. Therefore,
SUMMARY OF THE INVENTION In order to solve these conventional drawbacks, it is an object of the present invention to provide a thermal fixing device for a copying machine that can perform smooth thermal fixing regardless of the toner image on the paper.

[Means to solve the problem]

In order to solve the above problems, the present invention has a configuration in which a plate-shaped heater that emits far infrared rays is attached to the feed belt of a non-contact heat fixing device, and the back surface is heated by radiation while conveying the paper. I tried to eliminate uneven heat fixing.

[Function] The heat fixing device configured as described above is non-contact even during heating, so the toner image formed on the paper does not stick to the paper, and if a heater that emits far infrared rays is used, it can be directly Not only does electromagnetic waves act on the paper to heat the paper in an energy-efficient manner, but the paper is conveyed at a constant speed while radiant heating is applied to the back side of the paper, which has uniform brightness and darkness, allowing uniform heat exchange to occur over the entire paper, resulting in thermal fixing. Muragana (Naru)

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, a sheet 9 on which a toner latent image is formed is conveyed under pressure by a conveyance roller 1a and guided into the wall. The paper conveyed into the wall is conveyed to belt roller 1.
It is conveyed on the feed heald 4 wound around 7a and 17b. Further, when the paper conveyed on the heddle passes over the heater 7 installed in the feed heald, radiant heat due to far infrared rays is applied to the back side of the paper, and then the paper is heated by the conveyance roller 1.
It is discharged outside the wall by b. Next, the detailed mechanism will be explained. A conveyance roller 1a for conveying paper is driven by a motor 2 via a gear 3. The conveyance roller 1b is driven at the same speed as the conveyance roller 1a by a conveyance belt 19 wrapped around the conveyance roller 1a. Further, the relationship between the feeding speeds of the conveying roller la, the conveying roller 1b, and the feeding belt 4 is as follows: V1□V2. V, then V,=V,<V,
Power is transmitted through gear 5 to gear 6, which has a higher gear ratio than gear 3, so that the heald roller 17a is rotationally driven, and the feed heald 4 is driven.

The heater 7 is connected to the side wall 18a by brackets 8a and 8b.
.

18b, respectively. The fourth diagram in FIG. 4 shows a top view of one embodiment of the feed belt. The feed belt 4 is made of a flexible and heat resistant material such as glass wool, which is processed into a net shape. With this shape, the far infrared rays from the heater installed inside the belt can pass through the space 20 and radiate upwards of the belt, making it possible to radiantly heat the back side of the paper, which has a uniform heat absorption rate. can. Furthermore, the driving speed of the feed heald 4 is slightly higher than the rotational speed of the transport rollers la and lb to create a speed difference, so that far infrared rays are not continuously blocked by a part of the belt and a part of the paper.
Furthermore, due to the speed difference, one end of the paper does not enter the space in the belt, which also contributes to jam prevention. With this configuration, the back surface of the paper can be uniformly radiated heated, and as a result, the temperature of the toner latent image surface can be made uniform.

〔Effect of the invention〕

As described above, in the present invention, by arranging the plate heater on the back side of the paper, the paper can be fed smoothly during heating and can be fixed without staining the paper. Further, since the radiation of the heater is used on the back side of the paper, efficient heat conversion is possible, which has the effect of achieving heat fixing without uneven heating.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the heat fixing device of the present invention, FIG. 2 is a top view of the heat fixing device of the present invention, FIG. 3 is a vertical sectional view of the conventional heat fixing device, and FIG. Figures 1 and 2 are top views of the feed belt. la, lb...Conveyance roller 4...Feed belt 7...Heater 16...Outer wall 17a.17...Belt roller and above

Claims (1)

[Claims] In a thermal fixing device that heats and thermally fuses a toner latent image formed on a sheet of paper in a copying machine, etc., a heater is a means for heating the sheet on which a toner latent image is formed, and the sheet is conveyed under pressure. It is formed by a conveying roller as a means, a driving means for rotationally driving this roller, and a conveying means for conveying the paper,
A non-contact type heat fixing device, characterized in that it is formed so as to heat the back side of the paper while conveying the paper.