JPS60256179A - Heat fixing device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To take a sharp and soft copy of an image by providing a means which supplies a separating agent for toner to the surface of a fixing roller continuously or intermittently. CONSTITUTION:The fixing roller 1 is constituted by providing a room-temperature setting type silicone rubber layer 3 with superior oil resistance of a specular surface on a mandrel 2, and rotates as shown by an arrow while contacting color toner 5 sticking on copy paper 4. A heat conduction roller 14 covered with a thin rubber layer 13 which is made of rubber such as LTV on the mandrel 12 of iron, etc., and has the surface grounded to 0.3-1.0mm. is arranged at the opposite side of the sticking side of the color toner 5 of the copy paper 4. A halogen lamp 15 is installed in the hollow part of the mandrel of the heat conduction roller 14 and rotates as shown by an arrow while contacting the fixing roller 1. Further, felt 17 which is dipped at one terminal in silicone oil 16 is provided in contact with the outer peripheral surface of the fixing roller 1 and a proper amount of silicone oil is applied continuously over the surface of the silicone rubber layer of the fixing roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a heat fixing device for color toner in an electronic copying machine, particularly a full-color electronic copying machine.

(Technical background of the invention and its problems) Conventionally, in the heat fixing device of a typical electronic copying machine, a fixing roller made of a core metal coated with silicone rubber and the surface of which is ground flat is brought into contact with black toner. A heat transfer roller with a fluororesin coating on the surface on the opposite side is used, and the heat transferred from the heated heat transfer roller to the fixing roller transfers the toner onto the copy paper. The image is fixed by fusing the film to the film.

However, when it comes to the heat fixing device of a full-color electronic copying machine, the color toner used therein has a lower melting point than black toner and easily adheres to silicone rubber. A fusing roller with a ground surface could not be used. In other words, when the rubber roller surface is ground, fillers such as silica contained in the rubber are exposed to the surface, which not only makes it easier to adhere to toner, but also because the grinding creates fine irregularities on the rubber surface and toner is trapped in these recesses. This tends to clog and become a core of dirt, which tends to cause the copy paper to offset or get wrapped around the rollers. In order to prevent this phenomenon from occurring, a releasing agent such as silicone oil has traditionally been applied to the surface of the fixing roller in thermal fixing devices, but with a fixing roller whose surface has been ground, the offset This release agent cannot completely prevent the rubber coating layer of the roller from swelling, resulting in a shortened service life.

On the other hand, regarding heat transfer rollers, conventional rollers whose surfaces are coated with fluororesin require a high control temperature for the following reasons, and have a problem in that high-temperature offset tends to occur.

That is, the heat transfer roller has a small heat capacity, and the surface temperature of the fixing roller and heat transfer roller drops significantly when the copy paper passes through them, and it takes a long time to recover, so the heating temperature must be kept high. Ta.

(Objective of the Invention) The present invention has been made to solve these problems, and is designed for use in electronic copying machines, especially full-color copying machines, which has a long service life and does not cause toner offset to copy paper or copy paper wrapping around the fixing roller. An object of the present invention is to provide a heat fixing device for a copying machine.

(Summary of the Invention) The heat fixing device of the electronic copying machine of the present invention has a completely smooth surface (hereinafter referred to as a mirror surface) without any grinding, and at least the surface layer is room temperature hardened with excellent oil resistance. It consists of a fixing roller made of shaped silicone rubber, and a heat transfer roller that has a thin rubber coating layer with a surface ground on a core metal and has a built-in heating means. It is characterized by comprising means for intermittently supplying a toner release agent.

(Example of the invention) The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory cross-sectional view of one embodiment of the present invention.

In the figure, reference numeral 1 indicates a fixing roller, which is constructed by providing a room-temperature curing silicone rubber layer 3 with a mirror surface and excellent oil resistance on a core metal 2 made of iron, aluminum, stainless steel, etc. It rotates in the direction of the arrow while contacting the color toner 5 attached to the surface.

For example, the following method is used to manufacture such a fixing roller 1.

That is, as shown in FIG. 2, first, a stainless steel cylinder 7 whose inner circumferential surface is hard chromium plated and finished to a mirror finish is mounted upright on the cylindrical lower cap 6. After injecting the liquid silicone rubber 8 into the mold, the core metal 10 with the lower cap 9 attached thereto is inserted and fixed.

Next, after attaching the cylindrical top cap 11 to the upper part of the cylindrical body 7, the liquid silicone rubber 8 is completely cured at a temperature of approximately ±3° C., and then the cylindrical body 7 and the upper and lower caps are removed.

In this way, a fixing roller 1 with a mirror-like outer surface and no sink marks on the silicone rubber layer 3 due to its expansion and contraction is obtained.

In addition, on the side opposite to the color toner 5 adhesion side of the copy paper 4, grind the 5-shaped surface from rubber such as L'J'V or H'I'V on the core metal 12 made of iron, aluminum, stainless steel, etc. 0, 3-1. A heat transfer roller 14 covered with a thin rubber layer 13 having a thickness of OIIIB is disposed.

A halogen lamp 15 is built into the hollow interior of the core metal 12 of the heat transfer roller 14, and the heat transfer roller 14 itself rotates in the direction of the arrow while its outer peripheral surface is in contact with the aforementioned fixing roller 1. .

Furthermore, a felt 17 with one end soaked in silicone oil 16 is placed in contact with the outer peripheral surface of the rotating fixing roller 1, and an appropriate amount of silicone oil is continuously applied to the surface of the silicone rubber layer of the fixing roller 1. It is configured to

According to the heat fixing device of the embodiment configured as described above, a thin rubber roller having a larger heat capacity than the conventional one whose surface is coated with fluororesin is used as the heat transfer roller, so the heating control temperature can be controlled. It can be lowered from 150-155°C to 145-150°C, which not only saves energy but also does not cause high temperature offset. Furthermore, the heat transfer roller used in the examples has the advantage that it is not only easy to manufacture and inexpensive, but also has good paper passing properties and can produce soft images.

Furthermore, in the heat fixing device of the embodiment, the rubber layer of the fixing roller that directly contacts the color toner is made of a-flat-curing silicone rubber with excellent oil resistance, and the surface is finished to a mirror surface without grinding. No stains or offsets on the paper surface. In addition, since the rubber layer swells with silicone oil, the nib width can be increased and the load between the rollers can be reduced. Therefore, the service life of the fixing roller and the heat transfer roller is dramatically improved from the conventional 17,000 to 2,000 copies to 40,000 to 50,000 copies.

Next, another embodiment of the heat fixing device of the present invention is shown in FIG.

In this embodiment, a coating layer 18 made of a rubber foam such as a silicone rubber foam is provided on the core bar 2, and a thin surface layer 18 made of a room-temperature curing silicone rubber with excellent oil resistance and having a mirror surface is provided thereon. 19 is provided to constitute the fixing roller 1.

Further, the heat transfer roller 14 and the application mechanism for silicone oil 16 are both constructed in the same manner as in the embodiment shown in FIG.

The heat fixing device constructed in this way can not only exhibit all the effects described in the previous embodiments, but also has the following advantages.

In other words, the interior of the fixing roller 1 that comes into contact with the toner is made of a lightweight rubber foam with high heat insulation properties, which not only reduces heat loss, but also reduces the load between the rollers and prevents offset from occurring. It has the advantage of being long.

Specifically, the rubber foam covering layer 18 has a thickness of 4 mm, and the room temperature curing silicone rubber surface layer 19 has an outer diameter of 4 mm.
The heat fixing device is composed of a simple fixing roller 1 and a heat transfer roller 14 having a thin rubber layer 13 whose surface is ground to a thickness of 0.5 mm.The load between the rollers is extremely small at 100 kg, and the service life is 40,000 to 40,000 kg. It was extremely long with 50,000 yen possible.

For comparison, a fixing roller with an outer diameter of 5 Qsa and a heat transfer roller coated with a fluororesin on the surface and with an outer diameter of 60 cm was used in combination with a conventional heat fixing roller having a rubber coating layer with a mirror surface and a thickness of 5 mm on the core metal. Configured the device. The load between the rollers in this device is 9 in 40, and the service life is 17,000 to 2,000.
It took a short time with 0 copies.

(Effects of the Invention) As is clear from the above description, the heat fixing device of the present invention can produce clear and soft images without causing toner offset to copy paper, especially in full-color electronic copying machines. May be copied.

In addition, the heating control temperature can be set lower,
Extremely long service life.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of one embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing an example of the method of manufacturing the fixing roller in FIG. 1, and FIG. 3 is a cross-sectional view of another embodiment of the present invention. FIG. 1 ------------1-- Constant fixing roller 2.1
0,12---- Core metal 9- 3 -----1--------- Oil-resistant room temperature curing silicone rubber layer 5 --------------- Color toner 7
−−−−−−−−−−−− Cylindrical body 13 −−−−−
−−−−−−−− Surface ground thin rubber layer 14 −−−
−−−−−−−−−−− Heat transfer roller 16 −−−−−
−−−−−−−−−− Silicone oil 18 −−−
------ Rubber foam coating layer 19 ---
---------------Oil-resistant room-temperature curing silicone rubber surface layer 10-- Figure 1 Figure 2 Section = 7゜' J8 opening + 1. ': GO-25GI79 (4) Figure 3 7

Claims (1)

[Claims] 1. A fixing roller, which has a completely smooth surface layer made of oil-resistant room-temperature-curing silicone rubber, rotates while contacting the toner adhered to the copy paper and fuses it to the paper surface, and a thin-walled roller on the core bar. The heat transfer roller is provided with a rubber grinding layer, has a built-in heating means, and rotates in the opposite direction to the fixing roller while being in contact with the fixing roller. A heat fixing device for an electronic copying machine, comprising means for supplying a releasing agent for the toner to the toner.