JPH10123870A - Electrophotographic fixing method - Google Patents

Abstract

(57) [Problem] To realize a fixing method in which a surface layer made of a heat-resistant rubber-based material of a heating roll can withstand high-speed fixing for a long time and maintain good print quality. A heating roll having a surface layer made of a heat-resistant rubber-based material, a pressure roll provided so as to be able to press against the heating roll, and a release layer that comes into contact with the surface layer of the heating roll and are released from the surface layer A release agent application device for applying the agent, the recording material is nipped and conveyed while applying a heating and pressurizing action to the recording material at a pressure contact portion of the heating roll and the pressure roll, and is applied to the surface of the recording material. In the fixing method for an electrophotographic apparatus for fixing a toner image, the release agent coating device may be used at a temperature of 150 to 5 at room temperature.
A release agent having a viscosity of 000 centistokes is used, and the coating amount is set to an amount that satisfies the fixing of 200,000 pages to 1,000,000 pages per kg of the release agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fixing method for an electrophotographic apparatus.

[0002]

2. Description of the Related Art As a fixing device for fixing a toner image on the surface of a recording material, a heating roll having a surface layer made of a heat-resistant rubber-based material, and a pressure roll provided so as to be capable of being pressed against the heating roll are described. A release agent application device that contacts a surface layer of the heating roll and applies a release agent to the surface layer, and a heating / pressing action is performed on a recording material at a pressure contact portion between the heating roll and the pressure roll. While nipping and conveying the recording material,
There has been known an image forming apparatus in which a toner image is fixed on the surface of a recording material.

[0003]

However, in the case of a surface layer made of a heat-resistant rubber-based material, there has been a problem that the releasability, abrasion resistance and swelling resistance to a release agent are low.

[0004] In some products, the surface layer of the heating roll is formed of a Teflon-based material having high release properties, abrasion resistance and swelling resistance, but the surface layer is formed of a Teflon-based material. In the case of the formed heating roll, since the surface hardness is high, the toner forming the toner image tends to be crushed too much, and it is difficult to meet the demand for higher resolution.

[0005] An object of the present invention is to provide a heating roll in which a surface layer made of a heat-resistant rubber-based material can withstand long-term high-speed fixing.
Another object of the present invention is to provide a fixing method capable of maintaining good print quality.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a mold release agent having a viscosity of 150 to 50,000 centistokes at room temperature when a mold release agent is applied to a surface layer made of a heat-resistant rubber-based material of a heating roll. And setting the coating amount to an amount that satisfies the fixing of 200,000 pages to 1,000,000 pages per kg of the release agent.

Further, the toner image to be fixed is formed by using a toner having a molecular weight distribution (Mw / Mn) of 3 or more, which occupies about 90% of the toner.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a photosensitive drum for forming a toner image by an electrophotographic process,
Is supported by the support shaft so as to rotate at a constant speed in the direction of. The charger 2 is arranged so as to face the surface of the photosensitive drum 1, and uniformly charges the surface of the photosensitive drum 1 passing so as to face the charger 2. The laser beam 3 for exposing the uniformly charged surface of the photosensitive drum 1 is modulated in accordance with a print information signal supplied from an information processing device to form an electrostatic latent image on the surface of the photosensitive drum 1. The developing device 4
It is arranged so as to face the surface of the photosensitive drum 1 on which the electrostatic latent image is formed. The developing device 4 has a developing function of forming a toner image by attaching fine powder toner to the surface of the photosensitive drum 1 with electrostatic force of the electrostatic latent image.

A paper hopper 7 accommodates a continuous band-shaped recording material (printing paper) 6 for transferring and fixing the toner image and performing image printing in a folded state. The transport rollers 8a and 8b constituting a part of the printing paper transport unit are:
The printing paper 6 is taken in from the hopper 7 and sent out toward the photosensitive drum 1.

The printing paper 6 sent from the transport rollers 8a and 8b comes into contact with the surface of the photosensitive drum 1 so as to transfer a toner image to the surface. The transfer device 5 includes the photosensitive drum 1
A charge having a polarity opposite to that of the toner image is applied to the back surface of the printing paper 6 in contact with the surface of the photosensitive drum 1, and an electrostatic force for moving (transferring) the toner image formed on the surface of the photosensitive drum 1 to the surface of the printing paper 6 Generate.

Conveyance rollers 9a and 9b, which form another part of the paper conveyance means, feed the printing paper 6 on which the toner image has been transferred to the preheater 10. The preheater 10 is installed at a position on the front side of the fixing roll 11 and preheats the printing paper 6 by contacting the back surface of the printing paper 6 holding the toner image.

The preheater 10 has a configuration in which, for example, an electric heating element is attached to the back surface of the heat transfer member with which the back surface of the printing paper 6 contacts.
Heats the printing paper 6 to such an extent that the toner image attached to the printing paper 6 is softened while moving while contacting. The temperature of the preheater 10 is adjusted by controlling the current supplied to the electric heating element by the temperature control device 16.

A pair of fixing rolls 11 each comprising a heating roll 11a whose surface layer is formed of a heat-resistant rubber material such as fluororubber, and a pressure roll 11b pressed against the heating roll 11a.
Heats and presses the preheated printing paper 6 in contact with the preheater 10 to fix the toner image on the surface of the printing paper 6. The puller rollers 12 a and 12 b
Of the printing paper 6 sent out from the stacker 13
It can be folded in and stored or ejected outside the machine.

The release agent applying device 14 for applying a release agent such as silicone oil to the heating roll 11a has a printing speed of 200
In the case of about pages / minute, the viscosity at room temperature is 150 to 50,
The release agent set at 000 centistokes is applied to the heating roll 11a at an application amount set at 200,000 pages / kg to 1,000,000 pages / kg.

If the viscosity of the release agent is lower than 150 centistokes, the surface layer of the heating roll 11a tends to swell. On the other hand, if it is higher than 50,000 centistokes, the surface layer cannot be uniformly applied to the surface layer of the heating roll 11a. The amount of the release agent applied was 200,000 pages /
If the amount is smaller than 1 kg, the releasability decreases, and 1,000,000 pages / kg
If it is larger than this, the surface layer of the heating roll 11a tends to swell. Needless to say, the viscosity and application amount of the release agent vary depending on the printing speed of the electrophotographic apparatus. Furthermore, regarding the characteristics of the toner used, it was confirmed that when the molecular weight distribution (Mw / Mn) of the resin occupying about 90% of the toner was set to 3 or more, the releasability was further improved. Here, when the molecular weight distribution is set to 3 or less, although it depends on the type and application amount of the release agent (silicone oil), the releasability is reduced and offset is easily generated.

[0017]

As described above, according to the present invention, a surface layer made of a heat-resistant rubber material of a heating roll can withstand high-speed fixing for a long period of time and can maintain good print quality. The method can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an electrophotographic apparatus employing a fixing method of the present invention.

[Explanation of symbols]

11a: Heating roll, 11b: Pressure roll, 14: Release agent coating device.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Sawahata 1060 Takeda, Hitachinaka-shi, Ibaraki Prefecture Hitachi Koki Co., Ltd.

Claims (2)

[Claims] 1. A heating roll having a surface layer made of a heat-resistant rubber-based material, a pressure roll provided so as to be capable of being pressed against the heating roll, and contacting the surface layer of the heating roll and separating from the surface layer. A release agent application device for applying a mold agent, wherein the recording material is nipped and conveyed while applying a heating / pressing action to the recording material at a pressure contact portion of the heating roll and the pressure roll, and the recording material surface A fixing method for an electrophotographic apparatus for fixing a toner image on a surface of a toner,
A release agent having a viscosity of 00 centistokes was used, and the applied amount was 200,000 pages to 10 kg per 1 kg of the release agent.
A fixing method for an electrophotographic apparatus, wherein the fixing amount is set so as to satisfy fixing of 0,000 pages. 2. The electrophotography according to claim 1, wherein said toner image is formed by a toner having a molecular weight distribution (Mw / Mn) of 3 or more of a resin occupying about 90% of the toner. Device fixing method.