JPS59172668A - Pressure roller for fixation - Google Patents

Abstract

PURPOSE:To increase the nip width of the whole rubber layer while maintaining proper hardness in a surface layer of fluororesin by covering a thick foamed body layer formed around a shaft material with the thin surface layer of fluororesin. CONSTITUTION:The outer circumference of the foamed body layer 3 of silicone rubber which is formed thickly is covered with the surface layer 1 of fluororesin which deforms freely in a thin cylinder shape. Therefore, if a pressure roller 5 contacts a heat roller 4 on specific nip pressure, it deforms easily and the surface layer 1 of fluororesin is thin, so the roller deforms freely to make the nip width W to the heat roller 4 relatively large, thereby extending to the time of contacting with toner. Further, the surface layer 1 of fluororesin has hardness relatively higher than that of the foamed body layer 3, so the necessary nip pressure to the toner is secured and excellent fixing performance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure roller used in a fixing device consisting of a heating roller and a pressure roller of an electronic recording device, and relates to improvement of fixing properties, toner releasability, and lamps of the heating roller. This is an attempt to improve energy savings.

In general, when fixing toner images on paper in electrostatic recording devices such as electrophotographic copying machines, computers 0CR1, and facsimiles, there are two main methods: non-contact fixing methods, in which the toner is melted and fixed by irradiation with infrared rays, and heated rollers. There is a contact fixing method in which toner is heated and pressed for a predetermined period of time using a pressure roller to fix the toner on paper.

The latter contact fixing method has higher thermal efficiency than the former non-contact method and is capable of high-speed fixing, so it is currently widely used.

For example, in an electrophotographic copying machine, the conventional contact method using a heating roller and a pressure roller has a first
As shown in the figure, a heating rod (4) is coated with a fluororesin (7) on the outer periphery of a metal cylinder (6).
A pressure roller (5) coated on the outer periphery of silicone rubber (9) formed on the outer periphery of the shaft material (2) and fluororesin (8).
and a heating lamp (roller) in a heating roller (4). And pressure roller (5)
is pressed against the heating roller (4) with a predetermined pressure, for example, a total load of 120 f (hereinafter referred to as nip pressure), and the silicone rubber (9), which is an elastic body, is elastically deformed and is pressed against the heating roller (4). During the contact between fights 4 to 7,
). Note that unfixed toner (
When the paper (6) carrying the paper (6) passes between them, the unfixed toner (11>) absorbs thermal energy from the heating roller (4) while being subjected to nip pressure while passing through the nip width W, and the paper (11) to be melted and fixed.

However, this contact fixing method also has the following problems.

In particular, for the purpose of improving fixing performance, the nip pressure is increased/difficult and the rubber hardness of the pressure roller (5) is lowered to make the nip rl+
It was often done to increase the At that time, by increasing the nip width, the time for applying pressure to the toner is extended and the fixation of the toner to the paper is improved, but on the other hand, the heating roller (4) and pressure roller (5) The problem arises that the rotational torque increases and the motor has to be made more powerful. -jf, even when reducing the hardness of the rubber, the heat-resistant silicone rubber used conventionally has a limit of about 20° (JISH=), and could not fully satisfy the requirements.

Even if the fluororesin (8) of the surface layer (1) is removed and the hardness of the comb is excessively reduced, problems such as insufficient nip pressure, especially the nip pressure applied to the toner surface, and pressure roller (5) There also arises the problem of reduced durability.

In the present invention, the surface layer (1) of the pressure roller (5) maintains an appropriate hardness, while the rubber layer as a whole has a reduced rubber hardness in order to increase the nip width W. 5
).

That is, as shown in FIG. 2, in the present invention, a thick-walled, for example, noricorn rubber foam layer (3) is formed on the outer periphery of the shaft (2), and a thin-walled cylindrical layer is formed on the outer periphery of this foam layer (3). This is a pressure roller (4) characterized in that it has a shape and is coated with a surface layer (1) of a deformable fluororesin. A thin cylindrical deformable fluororesin surface layer (1) is coated on the outer periphery of a thick silicone rubber foam layer (3), and a pressure roller (5) is applied to the heating roller (4). When contacted with a specified nip pressure, a soft foam layer with silicone rubber inside (
3), it is easily deformed and the surface layer of fluororesin (1
) is also thin, so it can be deformed freely, and heated rollers (4
) can be made relatively large, and the contact time with the toner can be lengthened. In addition, since the fluororesin surface layer (1) has a relatively higher hardness than the foam layer (3), it is possible to secure the necessary nip pressure to the toner and obtain good fixing properties. can.

4. Since the outer periphery is coated with the surface layer (1) of fluororesin, the releasability of the I-ner is also maintained.

Historically, the inside of the pressure roller (5) was formed of a silicone foam layer (3), so the heating roller (5)
It has an insulating effect on the heat flowing from the heating roller (4) to the pressure roller (5), and can reduce the amount of heat supplied from the heating lamp (10) in the heating roller (4), which also has the side effect of helping to save energy.

In this manner, the present invention achieves its intended purpose by exhibiting excellent fixing properties and toner type properties, and also being effective in saving energy.

In addition, as for the materials constituting the pressure roller (5), the foam layer (3) includes EPD in addition to silicone rubber.
Synthetic coams with good heat resistance such as E, Phylcom, etc. can be used, and the fluororesin of the surface layer (1) may include tetrafluoroethylene resin (PTFE), tetrafluoroethylene hexafluoropropylene copolymer resin (FKP), etc. ), 4-57 ethylene, perfluoroalkoxyethylene co-tli synthetic resin (
A thin extruded tube made of PFA or the like can be used.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the operating state of a conventional example, and FIG. 2 is a longitudinal sectional view showing the operating state of an embodiment of the present invention. 1. Surface layer, 2. Shaft material, 3. Foam layer. Patent applicant Arai Seisakusho Co., Ltd.

Claims (1)

[Claims] A pressure roller for fixing, characterized in that a surface layer (1) of a fluororesin with an M thickness is covered with a thick foam layer (3) formed on the outer periphery of a shaft member.