JPS5851263B2 - Heat roller type fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat roller type fixing device used in electrophotographic copying machines and the like.

An electrophotographic copying apparatus employs a heat fixing method in which an electrostatic latent image formed on a photoreceptor is developed with a developer containing toner and then heated to melt and fix the toner image.

One of these thermal fixing methods involves inserting a recording paper carrying a toner image between a rotating heating roller and a rotating pressure roller in contact with the heating roller, and then using the heat from the roller to fuse the toner image. A heat roller type fixing device that fixes images onto recording paper is known.

Figure 1 is a schematic diagram of a typical heat roller type fixing device.
The heating roller 1 is made of a metal material such as aluminum, and the surface of the cylinder 11 is coated with a resin layer 12 such as Teflon, so that the surface of the cylinder 11 is coated with a resin layer 12 such as Teflon. A heat generating lamp 13 such as a halogen lamp as a heat generating source is arranged inside the device.

The pressure roller 2 is a metal cylinder 21 whose surface is coated 22 with a rubber material such as silicone rubber, and is pressed against the surface of the heating roller 1 with a weak force.

The heating roller 1 is rotationally driven at one shaft end by a drive device (not shown) and is supported pivotally at the other shaft end, while the pressure roller 1 is in pressure contact with the heating roller 1 and driven.

In such heat roller type fixing devices, various methods have been proposed to improve the toner releasability of the heat roller. Sometimes, a method of applying silicone oil to the surface of a heating roller or a method of using a Teflon-treated silicone roller as a pressure roller and causing silicone oil to seep out from the surface of the roller during use have been put into practical use.

The method of applying silicone oil requires an oil storage tank and application equipment, and the method of exuding silicone oil from the surface of the Locola has a limited period of use. A method has been developed and put into practical use in which the toner is coated with a resin such as Teflon and a treatment substance that improves mold releasability, such as low molecular weight polyethylene or low molecular weight polypropylene, is previously contained in the toner.

However, it has been empirically confirmed that this method, in which the surface of the heating roller is coated with a resin, has poor toner releasability at the initial stage, resulting in local adhesion of toner, that is, staining.

The reasons for this include variations in the fixing roller, localized areas with weak release properties, and stability of the fixing roller surface against stimulation from processes surrounding the fixing roller (for example, the fixing roller, cleaning means such as blades, transfer paper). Possible causes include insufficient release properties and insufficient supply of the release agent from the toner containing the release agent to localized weak release areas on the surface of the fixing roller.

Therefore, an object of the present invention is to improve the mold releasability of a heating roller coated with a resin such as Teflon from the initial stage.

The present inventors have developed a fixing device consisting of a Teflon-coated heating roller and a silicone rubber pressure roller by incorporating a releasing agent such as low molecular weight polyethylene or low molecular weight polypropylene into the toner. When a developer containing a toner with improved properties is used, the roller is initially smeared with the toner, but over time the Teflon coating adapts to the toner and gradually incorporates the release agent contained in the toner, releasing the mold. I recognized the fact that my sexuality was improving.

Based on this fact, Zara has discovered that the mold release agent is more compatible with rubber rollers such as silicone rubber than resin coatings such as Teflon, and the surface of the rubber roller is coated with low molecular weight polypropylene, low molecular weight polyethylene, alkylene bis fatty acid amide, etc. By treating with a so-called lubricant such as fatty acid ester and its partially saponified product, or paraffin wax, the lubricant is initially transferred from the rubber roller surface to the Teflon-coated heating roller surface, thereby improving the releasability of the heating roller against toner. This is an attempt to prevent the rollers from getting dirty, which tends to occur during cleaning.

Next, the lubricant used in the present invention will be specifically explained.

Polypropylene and polyethylene with a high molecular weight have poor mold releasability and are difficult to treat the surface of the pressure roller, so low molecular weight ones are used as lubricants, and those with an average molecular weight of 10
,000 or less, particularly preferably from 2,000 to 6,000.

As alkylene bis fatty acid amide, C1oH2□C0-NH-(CH2)5-NH-OCC
1oH21C1□H23CO-NH-(C)-I2)4
-NH-OCC11H23C13H27CO-NH-(
CH2)2-NH-OCC18H37C1oH21C0
-NH=(CI-(2)2-NH-OCC14I2゜C
15H3ICONH(CH2)2 NH-OCC15
H3□C1□H35CO-NH-CH2-NH-OCC
1□H3゜C1□H3, CC)-NH-(CH2)2-
NH-OCCl, H31C23H47CO-NH-C
H2-NH-OCC15H31゛”ゝ”0>N-(C Chapter-N〈0゛0“”.

C11H23COOCC11H23 1tJ, C,, Ho,, co>Nci-i, -N<OC
C,,i°゛C1□H35CO0CCH3 11°0"">N-(CH2)2-N<000"1゛C6H130CC5H1□ 12, C21)(,1CO-NH-CH2-NH-O
CC21H, 1”°°0...”’ ”>N-< CI(
,) 3-N<000...Tsu・C2H3COOCC21(
5 14, C17H35CO-NH-(C)(2)3-NH
-OCC17H35”0・crystal, co〉N=.

, -NH-6CC1,I3°C17H35CO As the fatty acid ester, esters of fatty acids and monohydric alcohols, esters of fatty acids and polyhydric alcohols, and partial esters of fatty acids and polyhydric alcohols can be used.

Partially saponified products of these fatty acid esters may also be used.

As the paraffin wax, natural paraffin, microwax, synthetic paraffin, chlorinated paraffin, etc. can be used.

In addition to the above-mentioned lubricants, the lubricants used in the present invention include higher fatty acids such as lauric acid, myristic acid, palmitic acid, and stearic acid; metal soaps such as zinc, lead, cobalt, and iron of the higher fatty acids; lauric acid amide and myristic acid; Fatty acid amides such as acid amide, stearic acid amide, behenic acid amide, oleic acid amide; lauryl alcohol,
Also included are higher alcohols such as palmityl alcohol, stearyl alcohol, and behenyl alcohol.

In the present invention, various methods can be considered for treating the surface of the rubber roller with a lubricant, including (1) a method in which a powdered treated material is sprinkled on the surface of the rubber roller and then heat-treated to blend it into the surface;
There are two methods: (1) a method in which the lubricant is dissolved in a solvent and coated on the surface of the rubber roller, and (3) a method in which the lubricant is heat-melted and then applied to the surface of the rubber roller.

Examples of the present invention will be illustrated below.

Example: The following lubricants A, B, C, D and E were processed using the following method (1):
, (2) and (3) make silicone rubber (strength 6
Fifteen pressure rollers coated with 00) were manufactured.

One pressure roller was manufactured which was not treated with a rough lubricant.

Lubricant A: Hoechst Wax PA-190 (manufactured by Hoechst, low molecular weight polyethylene) Lubricant B: Viscol 550-P (low molecular weight polypropylene, manufactured by Sanyo Chemical) Lubricant C: 150°C microparaffin (manufactured by Nippon Oil Company) Lubricant D= Exemplary Compound 2 Lubricant E Ethyl Stearate Treatment Method (1): After spraying a lubricant powder onto a pressure roller, heat treatment is performed at 150° C. for 15 minutes.

Processing method (2): Melt the lubricant and apply it to the pressure roller with a brush.

Processing method (3): A lubricant is dissolved in an organic solvent (eg, acetone, alcohol), applied to the pressure roller with a brush, and dried.

The amount of application (or amount of application) may be such that it can be uniformly spread (applied) over the entire surface of the pressure roller.

The fixing device used consisted of a Teflon-coated heating roller (with the cleaning blade removed) and the pressure roller, and used toner with release properties.
The experiment was conducted at a copy speed of 22 copies per minute (B-4 size) under the following fixing conditions.

Heating port → Set temperature 2200°C Teflon heating roller diameter: 40φ Roller rotation speed: 60RPM Roller pressure: 1.5ky/cIrL
In the experiment, we used an all-black chart original, and observed the stains on the roller after copying 1000 copies.We found that when a pressure roller that was not treated with lubricant was used, stains appeared on the roller, and if the stains were severe, the stains appeared on the recording paper. However, when a pressure roller treated with a lubricant was used, no staining of the roller was observed.

In the present invention, the pressure roller surface of the heat roller type fixing device is made of low molecular weight polypropylene, low molecular weight polyethylene,
Toner of a heating roller coated with resin by pre-treatment with a lubricant such as alkylene bis fatty acid amide, fatty acid ester and its partially saponified product, paraffin wax, higher fatty acid (or its metal soap), fatty acid amide, higher alcohol, etc. The mold releasability can be improved from the initial stage of fixing.

In this way, silicone oil such as special RTV silicone rubber (room-temperature curing silicone rubber) can be exuded from the surface of the reroller coated with silicone oil on the surface of the heat roller during fixing, thereby improving the releasability of the roller. There is no need for improvement, and there are great advantages such as easier maintenance of the fixing device.

The present invention can be applied not only to electrophotographic copying devices but also to facsimiles and fixing of electrostatic recording devices.

[Brief explanation of drawings]

The attached drawing is a schematic diagram of a heat roller type fixing device. 1... Heating roller, 11... Cylinder, 1
2...Resin layer 1.13...Heat lamp, 2...Pressure roller, 21...Metal cylinder, 22...Coating.

Claims (1)

[Claims] 1. Consists of a rotating heating roller whose surface is coated with resin, and a pressure roller that rotates in pressure contact with the surface of the heating roller and whose surface is coated with heat-resistant rubber, and the surface of the pressure roller is coated with a lubricant. Heat roller type fixing pill 2 characterized in that the lubricant is low molecular weight polypropylene, low molecular weight polyethylene, alkylene bis fatty acid amide, fatty acid ester and its partially saponified product, paraffin wax, higher fatty acid, metal soap of higher fatty acid. , fatty acid amide,
The hot roller type fixing island according to claim 1, characterized in that it is a higher alcohol.