JPH01206381A - Non-contact type thermal fixing device - Google Patents

Abstract

PURPOSE:To smoothly fix a sheet feeding in the course of heating by arranging a cylindrical fan and a plate-like heater. CONSTITUTION:A cylindrical fan 7 for generating a forced convection and a plate-like heater 10 for radiating far infrared rays are attached to the inside of the wall of a fixing device, and the flow of hot air by the rotational motion of a blade of the fan 7 is formed like a closed loop by a guide 13, etc. A form 14 on which a toner image, etc., are formed is brought to press-contacting and carried by a feed roller 1a, carried on a belt 4 for executing smoothly the feeding, and by the flow of hot air formed by the cylindrical fan 7 and the air guide 13, convection heat is applied to the surface of the form. Also, when said form passes through under the heater 10, radiation heat by far infrared rays is applied, therefore, it is discharged to the outside of the wall by a feed roller 1b. In such a way, a thermal fixation can be executed smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to (1) a thermal fixing device for thermally fusing a toner image, etc. on a sheet of paper, such as in a copying machine;

[Summary of the invention]

The present invention uses a cylindrical fan and a plate-shaped ceramic heater to heat the structure of a thermal fixing device that heats and thermally fuses a toner image formed on paper in a copying machine, etc., in a non-contact manner. By using not only convection but also radiation for heating, heating efficiency and heat fixing unevenness can be improved.

[Conventional technology]

Conventionally, as shown in FIG. 3(A), there is a contact type heat fixing device in which a heater 18 such as a halogen lamp is built into a hollow roller 17 to heat the paper, and as shown in FIG. 3(CB), outside air is blocked. A non-contact type heat fixing device has been known which includes an outer wall 19 for heating and a heater 20 for heating 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 image formed on the paper may adhere to the roller 17 and stain the paper, or depending on the type of toner, the roller 17 as shown in FIG. Wrapping around the edges could cause jams. In addition, in the case of a non-contact type heat fixing device, as shown in FIG. 3(B), it is formed by an outer wall 19, a heater 20, and a feed roller 21, and since it is heated by natural convection, the temperature inside the wall is extremely unstable. This has the disadvantage that it is difficult to uniformly fix the entire paper.

SUMMARY OF THE INVENTION Therefore, in order to solve these conventional drawbacks, it is an object of the present invention to provide a heat fixing device for a copying machine that can smoothly perform heat fixing regardless of the toner image formed on the paper. It is said that

[Means for solving problems]

In order to solve the above problems, the present invention installs a cylindrical fan for causing forced convection within the wall of a non-contact heat fixing device and a plate heater that emits far infrared rays, The flow of hot air is made into a closed loop using a guide or the like to eliminate stains on the paper and uneven heat fixation.

[Effect]

Since the heat fixing device configured as described above is non-contact even during heating, the toner image formed on the paper does not adhere. In addition, since far-infrared rays are emitted from the heater, N and magnetic waves act directly on the paper, making it possible to heat the paper with good energy efficiency. The temperature inside becomes uniform. Further, since hot air is applied uniformly in the line direction by the cylindrical fan, uniform heat exchange is performed on the paper, and by making the flow of the hot air into a closed loop using a guide or the like, thermal efficiency can be further improved.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. In Figure 1 (longitudinal sectional view) and Figure 2 (top view inside the wall),
A paper 14 on which a toner image and the like have been formed is conveyed under pressure by a feed roller 1a and guided into the wall. The paper that has entered the wall is conveyed on a belt 4 for smooth feeding.
Convection heat is applied to the paper surface by the flow of hot air formed by the cylindrical fan 7 and the air guide 13.

Furthermore, the paper conveyed on the belt is subjected to radiant heat from far infrared rays when passing under the heater 10, and is then discharged to the outside of the wall by the feed roller 1b.

Detailed mechanism will be explained. A roller la for feeding paper is driven by a motor 3 via a gear 2. Power is transmitted from a motor 9 by a spring 6 to a 6-cylindrical fan 7 which transmits power to the gear 2 via an intermediate gear 5 to a gear 6 to drive a belt roller 4. The heater 10 is fixed to the outer wall 12 by brackets 1.

As shown in the perspective view of the inside of the heat fixing device in FIG. 4, by arranging the air guide 13 between the cylindrical fan 7 and the heater 10, hot air circulates within the wall in a closed loop, resulting in more efficient heating. can. Furthermore, in the event of a paper jam, the wire mesh 22 prevents the paper from directly touching the heater 10.

Further, this will be explained in detail using FIG. The inside of the wall is divided into an upper part and a lower part by the air guide 13 and the heater 10. The flow of hot air is caused by the rotation of the cylindrical fan 7, which causes the air in the upper part to flow to the lower part, and is sent to the upper part again through the space behind the wall.

By adopting this configuration, a closed loop of hot air is formed and thermal efficiency is increased. Furthermore, since it is a cylindrical fan, a uniform heat flux is applied to the paper, allowing for even heat fixing.

Figure 6 shows a plan view of the heater.
is embedded in the base 16, and this structure can prevent the nichrome wire 15 from being oxidized. Furthermore, by using ceramic as the material of the base 2, a large amount of wavelengths of 1 to 2 μm, which have a high absorption efficiency of far infrared rays to paper, are generated.

〔Effect of the invention〕

As described above, according to the present invention, by arranging a cylindrical fan and a plate-shaped heater, paper can be smoothly fed during heating and can be fixed without staining the paper. Further, since the radiation and convection of the heater are utilized, heating can be performed with good thermal efficiency, resulting in the effect that heat fixing can be performed without uneven heating.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the heat fixing device of the present invention, FIG. 2 is an internal top view, FIGS. 3A and 3B are longitudinal sectional views of a conventional heat fixing device, and FIG. FIG. 5 is an enlarged sectional view of the fan section, and FIG. 6 is a plan view of the plate heater. la, lb...Feed roller 4...Heald 7...Cylindrical fan 10...Heater 12...Outer wall 13... ...Applicant for Air Guide and above Seiko Electronics Industries Co., Ltd. Top view of the inner structure 2

Claims (1)

[Claims] In a heat fixing device that heats and thermally fuses toner images formed on paper such as in a copying machine, an outer wall that substantially blocks outside air and a plurality of fan blades are arranged in a cylindrical shape tilted in the same direction,
A driving means for rotationally driving the fan blades, a heater for heating the inside of the wall, a feeding roller for pressure conveying, a driving means for rotationally driving this roller, and a conveying means for conveying the paper. A non-contact heat fixing device characterized in that the flow of hot air caused by the rotation of the fan blades is formed into a substantially closed loop using a guide or the like.