JPS6013512A - Rubber roller for thermal-fixing - Google Patents

Abstract

PURPOSE:To obtain the rubber roller for thermal-fixing with excellent antistatic property by coating the specified base polymer provided at the outer periphery of the roll core axis made of nonmagnetic metal with the composition containing antistatic agent, etc. CONSTITUTION:The rubber roller for thermal-fixing is made by a following method: (A) The end hydroxy-group sealed polydimethyl siloxane used as a base oil with viscosity of 1,000-7,000cps which is coated with the composition mainly composed of (B) silicon oil with the viscosity of 50-5,000cps, (C) inorganic filler, (D) cross linking agent, (E) curing catalyst and (F) antistatic agent, is provided at the outer periphery of the roll core-axis made of nonmagnetic metal. As this roller has an excellent antistatic property, a separating pawl and an electro-static eliminating brush, etc. are unnecessary, and the thermal-fixing part can be simplified. Then, as the roller has low creep property, pressurizing method can be adapted at all time, and the roller has the property of long life.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a pressure roller used in a heat fixing section of an electronic copying machine.

(@Ming's technical background and its problems) In dry electrophotography, what is the method of fixing the toner powder image transferred from the transfer drum onto a support such as paper on the support? A method is adopted in which the toner powder image is passed between a heating roller and a pressure roller and fixed by heating and pressing the toner powder image onto the entire support body.

In this method, unfixed toner powder adheres to the pressure roller, so a pressure roller with good releasability from the toner powder is required. More thermosetting type (HTV), addition reaction type (
L TV) or condensation reaction type room temperature curing m (几TV)
) Silicone rubber is used.

However, since I (TV or LTV silicone rubber is 41 heavy), it is composed of a -fC composition that contains a large amount of highly active inorganic silica, and has poor releasability with toner, so it is mixed into silicone oil after molding. There was a problem in that the surface of the rubber roller became dirty when 20,000 to 40,000 sheets were printed because the silicone oil impregnated with the reeds was agitated by the paper as it passed.

Although RTV rollers basically have excellent releasability from toner, the rubber has high electrical insulation properties, and therefore, when the roller rotates, it becomes charged due to friction, causing the problem that toner tends to adhere to the roller surface.

Frictional charging is a common problem for HTV, LTV, and RTV, and in addition to toner adhesion, it can also cause paper to wrap around the rollers. It discharges electricity.

In order to prevent this, it is necessary to attach a paper separation claw or a static eliminating brush, which also raises the problem of increasing the cost of the fixing section.

Generally, in an electrophotographic process, the photoreceptor is charged by one pass, and the toner is negatively charged, and although the toner transferred onto the copy i is neutralized, it is not completely removed and basically remains charged by one charge.

For example, the heat bonding section is composed of a heat roller fully coated with fluororesin and a press roller fully coated with silicone rubber. In this case, the potential generated by rotation is such that the heat roller side is negatively charged and the press roller side is glass charged.

Therefore, the toner tends to stick to the press roller side. Fluororesin has excellent electrical insulation properties, so it is very easy to be charged. Therefore, the material for the 7less roller needs to be as antistatic as possible. be. However, lowering the electrical resistance with carbon black or the like is not preferable because toner tends to adhere to it.

(Object of the Invention) The present invention has been made to address these problems, and provides a rubber roller for heat fixing that is oil-free, has excellent releasability from toner, and has good antistatic performance. The purpose is to

(Summary of the Invention) That is, the pressure roller of the present invention has a base oil of polydimethylsiloxane endblocked with hydroxyl groups having a viscosity of 1,000 to 7,000 centipoise on the outer periphery of a non-magnetic metal roll core shaft; 5000 centipoise silicone oil, 0 inorganic filler, CD) crosslinker,
(g) A composition containing a curing catalyst, an antistatic agent, and gold as a main component is provided as an entire coating layer.

The reason why the viscosity of the polydimethylsiloxane (6) used as the base oil in the present invention is limited to the above range is that if it is less than 100 centipoise, the physical properties of the rubber will be poor and the compatibility with low molecular weight silicone oil will be poor. If it exceeds 7,000 centipoise, the moldability of the roller deteriorates, and the releasability from the toner also decreases.

The reason why the viscosity range of the silicone oil (c) is limited as described above is that if it is less than 50 centipoise, the volatile content becomes large during use, and if it exceeds 5000 centipoise, it will bleed by itself. Preferably, it is in the range of 100 to 3000 centipoise.

Here, the mixing ratio of (e) and (c) is preferably 2.5 to 7 parts by weight per 100 parts by weight of (e), and the reason is 2.
This is because if it is less than 5 parts by weight, it tends to cause staining of the roller, and if it exceeds 7 parts by weight, the outer diameter of the roller tends to become thinner and it tends to creep.

Inorganic silica, Bengara, etc. can be blended as the inorganic filler, but the blending amount is preferably 40 to 60 parts by weight per 100 parts by weight of the composition. This is because the effect decreases and if it exceeds 60 parts by weight, the mold releasability is poor.

As the crosslinking agent for No. 0, organosilane compounds or siloxane compounds are suitable, such as ethyl normal I-ioate, phenylethoxysilane, ethyl polysilicate-4
0 (Union Carbide)' The blending amount thereof is preferably 2.5 to 5 parts by weight, more preferably 3.5 to 4 parts by weight, per 100 parts by weight of the base oil. If the amount added is less than 2.5 parts by weight, the degree of crosslinking will be insufficient, the tensile strength and tear strength will be low, and the creep properties of the housing will be poor.
If the weight part of the gold film is too low, it will be crosslinked too much and its mechanical properties will deteriorate.

In addition, in order to carry out a uniform crosslinking reaction, for example, 77% by weight of dimethyl silicone oil, 22xis of water, and 1 ffkt% of ethylene oxide emulsifier are added as additives, and 0.3 to 1 part by weight is added to 100 parts by weight of base oil. It is preferable to add

As the curing catalyst for (2), a tin-based catalyst or the like can be used. These crosslinking agents and catalysts can be used as a compound by mixing silicone oil such as dimethyl silicone oil or phenylmethyl silicone oil as a diluent and adjusting the blending ratio with the main body in an appropriate amount commensurate with the work.

An example of the composition may be 65% by weight of crosslinking agent, 2% by weight of catalyst, and 33% by weight of phenylmethyl silicone oil.

Corn oil or the like can be used, for example, KF351.352.353 manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

Also, the amount of antistatic agent added is 0 relative to the amount of base polymer.
．． The reason why 1 to 3 parts by weight is preferable is that if the amount added is less than 0.1 part by weight, the antistatic effect will be small, and if it exceeds all 3 parts by weight, the amount of deterioration and creep will increase, and the roller surface will become more contaminated. It is.

Next, a method for manufacturing a pressure roller according to the present invention will be explained.

The mixing method is not particularly limited, but 0,
(c) When the ingredients are added, the curing reaction begins (g) ~
It is desirable to mix component 0 as uniformly as possible, and then add and mix components 0 to 0.

The paste-like composition thus obtained is injected into a cylindrical mold into which a core metal with a primer syllable is inserted as needed, and left to stand at room temperature to about 100°C for several hours to harden. The pressure roller of the present invention is manufactured by grinding according to the following.

(Example of the invention) Next, examples of the present invention will be described.

[Example 1.2 and Comparative Example] The components shown in Table 1 were mixed to obtain a paste composition. The composition is molded into a sheet shape by a conventional method and then cured.
Physical property tests shown in the table were conducted.

Table 1 (Parts by weight) The numbers in parentheses for each of the above components are trade names manufactured by Shin-Etsu Chemical Co., Ltd.

On the other hand, it was poured into a cylindrical mold into which a degreased and coated 7' limer core had been inserted, and left at 70° C. for 2 hours to harden. After hardening, the outer surface is ground to an outer diameter of 40 m.
A pressure roller T having a rubber thickness of 5 m was manufactured. Tests shown in Table 3 were conducted using Teflon-coated rollers as the pressure roller and heating roller.

The paper passing test was carried out at a heating roller control temperature of 195° C., an inter-roller load of 55 edges, a roller effective length of 300 m, a copy paper conveyance speed of 150 m/sec, and A4 size paper passing.

Part 2 Notes 1. Tensile strength and elongation were measured in accordance with JIS K 6301K.

Note 2. Chargeability is determined by static honest meter.

Charge is 5KV, distance between electrodes is 151! lI0 Table 3 (Effects of the Invention) As is clear from the above examples, the heat fixing rubber roller of the present invention has good antistatic performance, so there is no need for separating claws or static eliminating brushes, The fixing section can be simplified, and since it is a low-creep roller, a constant pressure method can be used, and the roller life is long.

Claims (1)

[Claims] 1. On the outer periphery of the roll core shaft made of non-magnetic metal, (g) viscosity 10
00 to 7,000 centipoise end-blocked polydimethylsiloxane as a base oil, (c) silicone oil with a viscosity of 50 to 5,000 centipoise, (C
1. A rubber roller for heat fixing, characterized in that a coating layer is provided with a composition containing as main components: (1) an iridescent filler, (g) a crosslinking agent, (2) a curing catalyst, and (0) an antistatic agent. 2. The amount of silicone oil is base oil 100.
The rubber roller for heat fixing according to claim 1, wherein the amount is 2.5 to 7 parts by weight. 6. The rubber roller for heat fixing according to claim 1 or 2, wherein the inorganic filler is blended in an amount of 40 to 60 parts by weight per 100 parts by weight of the composition. 4. The rubber roller for heat fixing according to any one of claims 1 to 6, wherein the antistatic agent is blended in an amount of 0.1 to 3 parts by weight per 100 parts by weight of the base oil.