JPS62187372A - Fixing device - Google Patents

Abstract

PURPOSE:To eliminate an irregularity in fixation and to obtain a fixed image of high quality by providing two rotating bodies which clamp an image receiving body and equipping the 1st rotating body with a core material, a porous heat- resistant elastic layer provided to the periphery of the core material, and a constituent material with a porous fluororesin layer outside the layer. CONSTITUTION:A heat fixing roller 30 is heated by a heating means 39 to prescribed temperature as it rotates, the porous fluororesin layer 33 on the surface is coated with offset preventive liquid by a coating means 42, and a nip F is formed between the roller and a pressure roller 34 pressed by a pressing means 38. The outermost layer of the heat fixing roller 30 consists of the porous fluororesin layer 33 and the offset preventive liquid is applied to this part, so the wettability of the offset preventive liquid to the fluororesin layer 33 is improved and the offset preventive liquid is applied to an invariably uniform amount without being localized. Further, the width of the nip F increases, so a toner image 43 on paper 44 is heated and pressed sufficiently and fixed by complete fusion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fixing device for heating and fixing a toner image to an image receptor such as paper, and relates to a fixing device for heating and fixing toner images on an image receptor such as paper, and for fixing images in copiers, printers, etc. that apply electrostatic printers and electrophotography. The present invention relates to a fixing device that can be applied to a forming device.

Conventional technology A fixing device that fixes a toner image formed by an image forming method such as electrophotography onto a recording material such as paper includes a fixing roller that is heated by a heat source and a pressure roller that is in pressure contact with the fixing roller. A configuration is often used in which a paper holding a toner image is conveyed, and the toner image on the paper is heated and pressurized to melt and fix it.

The fixing device with this configuration is based on a heat roller system, which has high thermal efficiency and excellent fixing performance, and is still effective in Hiroshima. In order to obtain a fixed image, it is necessary to sufficiently melt the toner, eliminate toner off-setting to the fixing roller during fixing, and prevent the occurrence of paper wrinkles and the like.

Therefore, the conventional fixing device has a structure as shown in FIGS. 2 and 3, as disclosed in Japanese Patent Publication No. 56-6549.

In FIG. 2, reference numeral 4 denotes a heating fixing roller, and an offset prevention layer 1 made of silicone rubber. : It is composed of a support body 2 made of silicone rubber foam impregnated with silicone oil, which is an anti-offset liquid, and a shaft 3. 5 is a heater that heats the heat fixing roller 4; A pressure roller 6 is in pressure contact with the heat fixing roller 4.

The paper holding the toner image is conveyed between a heat fixing roller 4 heated by a heater 6 and a pressure roller 6 pressed against the roller, and the toner image on the paper is heated and pressurized to melt and melt the toner image on the paper. will be established. During fixing, the silicone oil impregnated in the support 2 seeps out onto the surface of the heat-fixing roller 4 to prevent toner offset and paper wrapping around the heat-fixing roller 4. Further, the support body 2 of the heat fixing roller 4 is made of silicone rubber foam to lower the hardness of the heat fixing roller 4, thereby increasing the pressure contact width between the heat fixing roller 4 and the pressure roller 6 (hereinafter referred to as the nip width). By increasing the heating time of the toner image, the toner is sufficiently melted.

FIG. 3 shows another conventional example, in which the heat fixing roller 2° is made of an offset prevention layer 26 made of Teflon (trade name) with minute holes and glass fiber impregnated with silicone oil, which is an offset prevention liquid. A heater 22 for heating the heat-fixing roller 2o is disposed inside the metal tube shaft 23, and the support body 24 is made up of a metal tube shaft 23 and a roller shaft 21. The silicone oil impregnated in the roller 24 oozes out to prevent toner offset and paper wrapping around the heat fixing roller 2o.

Problems to be Solved by the Invention However, with the conventional fixing device as described above, good fixing performance can be obtained at the initial stage of use, but after continued use for a long period of time, the silicon impregnated in the support 2 (or 24) may deteriorate. Oil tends to decrease, and eventually the heating fixing roller 4 (or 20)
Toner offset and paper wrapping occur, resulting in deterioration in image quality and paper jams. In addition, if the pressure force between the heating fixing roller 4 (or 20) and the pressure roller 26 becomes even slightly uneven partially in the longitudinal direction,
The amount of silicone oil exuding from the support 2 (or 24) differs locally, resulting in uneven fixation and deterioration of image quality.

Furthermore, in the case of the configuration shown in FIG.
The offset prevention layer 1 made of silicone rubber and the support 2 made of silicone rubber foam are impregnated with silicone oil for a long period of time and swell, resulting in poor surface cylindrical precision of the heat fixing roller 4 and uneven fixing. This caused deterioration in image quality and shortened the lifespan of the fixing device.

The present invention solves the above-mentioned conventional problems, and has a simple structure that sufficiently melts toner, prevents toner offset, paper jam, uneven fixing, and shortened lifespan, and always produces high-quality fixed images. The object of the present invention is to provide a fixing device that can be obtained.

Means for Solving the Problems The technical means of the present invention for solving the above-mentioned conventional problems is to heat the first rotating body (conventional example) by heating means (heater 6 or 22 in the conventional example). Then heat fixing roller 4 or 2
0) is composed of a core material, a porous heat-resistant elastic layer provided around this core material, and a porous fluororesin layer provided outside this heat-resistant elastic layer, and this first rotating body The anti-offset liquid is applied to the surface by a coating means.

action The effect of this technical means is as follows.

That is, the first rotating body is composed of a core material, a porous heat-resistant elastic layer provided around the core material, and a porous fluororesin layer provided outside the heat-resistant elastic layer, and the offset By applying the anti-offset liquid only to the porous fluororesin layer of the first rotating body, a uniform amount of anti-offset liquid can be supplied to the surface of the first rotating body at all times, and also during the first rotation. The hardness of the body is reduced, making it possible to increase the nip width (that is, the area where the toner image is heated and pressed).

As a result, it is possible to prevent uneven fixing, toner offset, and paper jam that occur due to non-uniform oozing or reduction of the offset prevention liquid impregnated in the conventional method. This prevents the lifespan from shortening and allows high-quality fixed images to be obtained at all times.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In FIG. 1, 30 is a heating fixing roller which is a first rotating body, and is provided with a core material 31 and the outer periphery of this core material 31.
It is composed of a heat-resistant elastic layer 32 made of silicone rubber foam having a large number of closed cells, and a porous fluororesin layer 33 provided on the outside of this heat-resistant elastic layer 32, and rotates in the direction indicated by the arrow.

The fluororesin layer 33 has, for example, a pore diameter of 0.2 to 8 μm.

It is a porous body made of tetrafluoroethylene resin with a porosity of 26 to 95%, and Boaflon (trade name) manufactured by Sumitomo Electric Industries, Ltd. or the like can be used.

34 is a pressure roller which is a second rotating body, and is made of SUS or A
It is composed of a tube shaft 35 made of a first-class metal material, and an offset prevention resin 36 such as Teflon or silicone rubber provided on the outer periphery of the tube shaft 35, and is pressed against the heat fixing roller 30 by a pressure means 37, which will be described later. and rotates in the direction of arrow B.

Reference numeral 37 denotes a pressure means for pressing the pressure roller 34 against the heating fixing roller 3o, and for example, a compression spring 38 or the like is effectively used. Reference numeral 39 denotes a heating means for heating the heat fixing roller 30, which is composed of, for example, a heating lamp 4o and a reflecting mirror 41.

Reference numeral 42 denotes a coating means for applying an anti-offset liquid such as silicone oil to the surface of the heat-fixing roller 30, and the anti-offset liquid supplied by an anti-offset liquid supply means (not shown) is constantly or intermittently applied to the heat-fixing roller 3o. Apply to the surface.

Next, the operation of the configuration of this embodiment will be explained.

As the heating fixing roller 3o rotates, the heating means 39
The coating means 42 is heated to a predetermined fixing temperature by
An anti-offset liquid is applied to the surface of the porous fluororesin layer 33, and a nip F is formed between the pressure roller 34 and the pressure roller 34 pressed by the pressure means 38.

In this embodiment, the outermost layer of the heat fixing roller 3o is composed of a porous fluororesin layer 33, and an anti-offset liquid is applied to this portion.

The wettability of the anti-offset liquid to the fluororesin layer 33 is improved, and the anti-offset liquid is not applied partially unevenly, and a uniform amount of the anti-offset liquid is always applied.

Also, here, the heat-resistant elastic layer 32 inside the fluororesin layer 33
Since it is made of silicone rubber foam having many closed cells, the anti-offset liquid will not be impregnated into the inside of the heating fixing row 230, and will always be applied only to the fluororesin layer on its surface. Along with this, the heating fixing roller 30
If the hardness of the toner image is low, the width of the nip F (that is, the area where the toner image is heated and pressurized) can be increased. Then, the paper 44 holding the toner image 43 formed by an image forming method such as electrophotography is conveyed between the heat fixing roller 3o and the pressure roller 34 in the above state, and the paper 44 is
The toner image 43 on the toner image 43 is sufficiently heated and pressurized to be completely melted and fixed.

As described above, in the fixing device of this embodiment, the outermost layer of the heat fixing roller 3o is composed of a porous fluororesin layer 33, and the inner heat-resistant elastic layer 32 is made of silicone rubber foam having a large number of closed cells. Since the anti-offset liquid is applied to the porous fluororesin layer 33, the anti-offset liquid is impregnated inside the heated fixing roller 30 as in the conventional method, and the anti-offset liquid oozes out. It is possible to always apply a uniform amount of anti-offset liquid to the surface of the heat fixing roller 30 even if the anti-offset liquid is not supplied to the surface of the heat fixing roller 3o. The width (that is, the area where the toner image 43 is heated and pressurized) can be increased.

Therefore, the constant fl.
It is possible to prevent unevenness, toner offset, and paper jam, and also to prevent shortening of device life due to impregnation with offset prevention liquid, and it is possible to always obtain high-quality fixed images.

Effects of the Invention The present invention provides a first rotating body made of a core material, a porous heat-resistant elastic layer provided around the core material, and a porous fluororesin layer provided outside the elastic layer. Since the anti-offset liquid is applied only to the porous fluororesin layer of the first rotating body, the anti-offset liquid is impregnated into the inside of the first rotating body as in the conventional case. Even if this anti-offset liquid does not seep out and is supplied to the surface of the first rotating body, a uniform amount of the anti-offset liquid can always be applied to the first rotating body, and The body becomes less hard and the nip width can be increased.

As a result, it is possible to prevent uneven fixing, toner offset, paper jam, and shortened device life that have conventionally occurred, and it is possible to always obtain high-quality fixed images.

[Brief explanation of drawings]

FIG. 1 is a central sectional view of a main part of a fixing device according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of a conventional fixing device, and FIG. 3 is a heating in another embodiment of a conventional fixing device. FIG. 3 is a cross-sectional view of the fixing roller. 30...First rotating body, 31...Core material, 32...Porous heat-resistant elastic layer, 33...
... Porous fluororesin layer, 34 ... Second rotating body, 37 ... Pressure means, 39 ... Heating means, 42 ... Application means. Name of agent: Patent attorney Toshio Nakao and one other person 3θ
---In the 1st/1st episode, salary 31--11 Shiki material 37--Additional provision 39--jJU Retsuko death provision Figure 42-4:4 Child actor 4? Figure 2 22' 2/

Claims (2)

[Claims] (1) A fixing device that heats and fixes a toner image on an image receptor, comprising first and second rotating bodies that sandwich the image receptor, and a fixing device that heats the first and second rotating bodies. a pressurizing means for applying pressure, a heating means for heating at least the first rotating body, and an application means for applying an anti-offset liquid to the surface of the first rotating body; A fixing device comprising a component having a core material, a porous heat-resistant elastic layer provided around the core material, and a porous fluororesin layer provided outside the elastic layer. (2) The fixing device according to claim 1, wherein the porous heat-resistant elastic layer is a silicone rubber foam having a large number of closed cells.