JPH0199077A - Production of thermal fixing roller - Google Patents

Abstract

PURPOSE:To greatly improve working efficiency by coating fluorinated resin on an elastic rubber layer provided on the arbor of a roller, then holding the arbor of the roller for the time specified by the specific equation in a heating atmosphere of 580-620 deg.C, thereby baking the coating. CONSTITUTION:Silicone rubber is vulcanized and adhered via a primer onto the aluminum arbor of the roller. The surface of the silicone rubber is ground after the vulcanization to form the silicone rubber layer. The fluorinated resin such as polytetrafluoroethylene resin or perfluoroalkoxy resin is coated on the surface of the rubber layer and thereafter, this fluorinated resin coating is baked. The baking is executed by holding the unbaked arbor of the roller for the time given by equation I in the heating atmosphere kept at 580-620 deg.C, thereby baking the coating. In equation, T is the time (sec) and W is the weight (g) of the roller after the formation of the elastic rubber layer. The need for making experiment for the purpose of setting the conditions at every change of a roller size, etc., is then eliminated and the working efficiency is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a heat fixing roller used in a heat fixing section of an electronic copying machine or the like.

(Prior art) Conventionally, heat fixing rollers used in heat fixing units of electronic copying machines, etc., have been made by coating rubber materials such as silicone rubber or fluororubber on a metal core shaft made of aluminum via a primer. is commonly used. In order to improve the releasability of such a roller from the toner, polytetrafluoroethylene resin (hereinafter referred to as PTFE) or perfluoroalkoxy resin (hereinafter referred to as PFA) is added to the surface of the rubber layer.
It is called. ) is coated with a fluororesin and fired to provide a fluororesin layer.

By the way, when manufacturing such rollers, the firing conditions for the fluororesin greatly affect the quality and performance of the roller, so in the past, preliminary experiments were conducted to determine the preferred firing conditions, and then multiple roller core axes were used. The common method was to hold the main edges together, store them in a heating furnace, and fire them all at once.

(Problem to be solved by the invention) However, in this conventional method, it is necessary to conduct preliminary experiments to determine firing conditions every time the size, weight, or number of cores to be accommodated changes, which is time-consuming. The problem was that it was time consuming and inefficient.

Moreover, because it is difficult to maintain a uniform temperature distribution in the heating furnace, there may be excess or deficiency in firing depending on the position where the roller is placed, making it difficult to consistently manufacture high-quality, high-performance rollers. was there.

That is, if the firing is performed excessively, the rubber layer, which is the base layer, will be thermally degraded, and if the firing is insufficient, the mechanical properties of the fluororesin layer will be poor.

Therefore, the present invention was made to solve these conventional difficulties, and it is possible to uniformly sinter fluororesin under favorable conditions without conducting preliminary experiments to determine the conditions, greatly improving work efficiency. It is an object of the present invention to provide a method capable of stably manufacturing a heat fixing roller of high quality and high performance.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a rubber elastic layer on a roller core shaft made of aluminum, coats the rubber elastic layer with a fluororesin, and then removes the fluororesin coating. When firing, the roller core shaft was placed in a heated atmosphere at 580 to 620°C using the following formula (% formula %) (where T is time (seconds) and W is the weight (q) of the roller after forming the rubber elastic layer). ) is characterized in that it is fired by holding it for a given time.

In the present invention, if either the heating temperature or the heating time is out of the above range, it is not preferable because it will result in excessive or insufficient firing, leading to thermal deterioration of the rubber layer or deterioration of the mechanical properties of the fluororesin layer.

The rubber materials constituting the rubber elastic layer of the present invention include:
Silicone rubber and fluororubber with excellent heat resistance are suitable.

The fluororesin coated on this rubber elastic layer includes PTFE, PFA, FEP (tetrafluoroethylene/hexafluoropropylene copolymer), etc., and the coating method is fluororesin tispersion. Known methods can be used, such as dipping, spraying, etc., and applying fluororesin powder by electrostatic coating.

(Function) In the present invention, suitable firing conditions can be determined by calculation just by knowing the weight of the roller after the rubber elastic layer is formed. There is no need to carry out any experiments, and work efficiency is greatly improved, and high-quality, high-performance heat fixing rollers can be stably manufactured.

<Example) Examples of the present invention will be described below.

First, silicone rubber (G-968, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to five types of aluminum (JIS A-5056) cores of different weights using a primer using a conventional method.
After vulcanization, the surface was ground to form a silicone rubber layer.

Next, PTFE dispersion (AD-639 manufactured by Asahi Glass Co., Ltd.) was applied to the surface of the silicone rubber layer by the dip = 5- method, and the coated surface was dried to remove the PTFE dispersion powder, etc. to form a PPTFE coating. Obtain a PTFE green roller having the following shapes and weights as shown in the table.

After this, each of the unobtained rollers, one by one, is
A small heating furnace (capacity 0.5Tl13.
The PTFE coating film was fired by placing the sample in a 18 kW heater built-in and a stirring fan installed at a wind speed of 2.41/sec and holding it for the time shown in the table while operating the stirring fan.

The thermal deterioration of the silicone rubber layer and the mechanical properties of the PTFE layer of each PTFE-coated silicone rubber roller thus obtained will be shown in the next section.

The thermal deterioration of the rubber layer was expressed as the rate of change in mechanical properties after firing compared to before firing.

(The following is a blank space) As is clear from the table, the rollers manufactured according to the present invention have little thermal deterioration of the rubber layer and good mechanical properties of the PTFE layer, despite the difference in weight.

[Effects of the Invention] As explained above, according to the present invention, it is possible to uniformly sinter the fluororesin under favorable conditions without conducting preliminary experiments to determine the conditions, and work efficiency is greatly improved. It becomes possible to stably manufacture high-quality, high-performance heat fixing rollers.

Claims (1)

[Scope of Claims] After a rubber elastic layer is provided on a roller core shaft made of aluminum and a fluororesin is coated on this rubber elastic layer, when this fluororesin coating is fired, the roller core shaft is
In a heated atmosphere at 620°C, the following formula T = a√W (1.9 < a < 2.1) (where T is time (seconds) and W is the weight of the roller after forming the rubber elastic layer (g)) A method for manufacturing a heat fixing roller, characterized in that baking is performed by holding the roller for a given time.