JPS6080888A - Roller for pressure fixing - Google Patents

Abstract

PURPOSE:To prevent generation of luster on a recording material and to prevent staining by providing a ceramic layer or cermet layer on the surface of a fixing roller and coating the surface thereof with a resin having releasability from a material to be fixed. CONSTITUTION:A fixing roller is of the constitution in which a resin layer 9, a ceramic or cermet layer 10 and an undercoating layer 11 for preventing stripping between the ceramic or cermet layer and a roller base body 12 are formed successively from the surface thereof on the body 12. The layer 10 has a matte surface by which the generation of luster of a recording material is prevented. The resin layer 9 fills the recesses of the layer 10 by which the intrusion of the material to be fixed into the recesses of the ceramic layer is prevented and the staining of the recording material is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device for an image forming apparatus such as a printer, a copying machine, a facsimile, or a printing press, and mainly to a pressure fixing roller for pressure fixing.

Pressure fixing is generally a method in which a recording material such as paper or a resin sheet is passed between a rotating body for fixing such as a roller or a belt, and an object to be fixed such as toner or ink is fixed on the recording material. Pressure fixing has advantages such as a short fixing time, and is applied to fixing devices such as the above image forming apparatuses and printing machines.

Conventionally, a problem associated with this fixing device has been that the recording material becomes glossy. In other words, the fixing roller is
Generally, those with a mirror finish are used, but this causes gloss.

For example, in copying machines, a steel fixing roller with a mirror-finished surface is generally used, but in order to fix a toner image on copy paper, it is necessary to apply an average linear load of Ikg/CrIL or more. Ta. however,/
If a pressure of 2 ky/(y or more is applied), the copy paper becomes smooth and glossy, which is an unavoidable problem.

In order to solve this problem, the surface of the fusing roller is subjected to frequency hardening, hard CR plating, etc. to improve the surface (convenience) and the lifespan of the fusing roller. The matte treatment is a process in which the surface of the fixing roller is subjected to a last treatment to give the surface matte-like unevenness, and this gives the copy paper 15 depressions to prevent it from matting.

However, in the above method, (1) a square g
Since a pressure greater than 3 is applied, the abrasion is severe, and the matte surface disappears, immediately causing the copy paper to become glossy -/1.

(2) Toner enters the recessed portions of the mat and is retransferred, staining the copy paper, or causing problems such as the toner that enters the mat recesses stripping off the toner on the copy paper.

The present invention has been made in view of the above points.

The purpose of the present invention is to prevent the generation of gloss on the recording material, prevent recording (side stains), and improve the abrasion resistance and durability of the recording material. An object of the present invention is to provide a fixing roller.

In short, the present invention provides a fixing device that passes a recording material between a fixing roller provided on the side that contacts the fixing material and a pressure means facing the fixing roller, and fixes the fixing material on the recording material by pressure. The fixing roller according to the present invention has a ceramic layer or a cermet layer on the surface of the fixing roller, and the ceramic layer or the cermet layer is coated with a resin that is removable from the fixing material. It is.

First, pressure fixing will be described based on an embodiment of a fixing device of an image recording apparatus to which the present invention is applied.

In FIG. 1, the fixing roller on the side that contacts the fixing material, the pressure roller that is a means for pressurizing the fixing roller, and the fixing roller according to the present invention are the fixing roller of the present invention, and the roller bases /', 2' and ceramic It consists of layers ////, 2//1 and resin coating layers /", 2".

The fixing roller/pressure roller is connected to the upper plate 3 at each end thereof. It is rotatably supported by the lower plate. This upper plate 3. The lower plate is rotatably pivoted at one end by a support shaft S, and at the other end is connected to the side plates 3. In the evening, the bolt A to open this, and the pie set around the bolt O.7. A pressing force ω is applied by the action of which three members (and a spring that compresses the spring 7 and generates a repulsive force). This pressing force ω is multiplied by the side plate part according to the lever principle, and the total load W (W) ω between the fixing roller and the pressure roller, the average linear load obtained by dividing W by the roller length is 20 to 30 kghL) It acts as. This load W acts directly on the plain paper p supporting the toner image T, and fixes the toner image T on its surface under pressure. The fixing roller is driven one rotation in the direction of the arrow by a motor (not shown) via a gear (not shown) provided at its end.

The pressure roller λ is moved upward in the direction of the arrow by the frictional force (by the roller / when there is no paper p between the rollers / and by the paper p when the paper p is pressed between the rollers / and 2). Rotate.

Due to the rotation of both rollers /, 2, the paper p advances in the direction of the arrow,
Pressure fixing of the toner image T progresses. The supporting surface of the toner image T on the paper p is pressed against a fixing roller, and the back surface thereof is brought into pressure contact with a pressure roller.

In the above example, a fixing device of an image recording apparatus was described, but a fixing device to which the fixing roller of the present invention is applied is not limited to the above example, and fixing is performed by a fixing roller and a pressure means facing the fixing roller. This can be applied to any fixing device that performs this process.

Next, the fixing roller of the present invention will be described based on the embodiments shown in FIGS. 2 to 9, in which an undercoat layer is provided to prevent peeling of the ceramic layer or cermet layer.

FIG. 2 is a sectional view of the fixing roller of this example taken along a plane including the rotating shaft, and FIG. 3 is a sectional view taken along line A-A' in FIG. The structure of the fixing roller of this example is as follows from the surface: resin layer 9. Ceramic layer or cermet layer 10. It consists of a ceramic layer or a cermet layer, an undercoat layer for preventing peeling of the roller base/2, and a roller base/2.

The ceramic layer or cermet layer has a matte surface as shown in FIG. 9, which prevents the recording material from becoming glossy. Further, by filling the recesses of the ceramic layer or the cermet layer with the resin layer, the material to be fixed is prevented from entering the recesses of the ceramic layer, thereby preventing staining of the recording material. In this example, the resin coating state is resin-, but it does not necessarily have to be a resin layer, as long as it can prevent the material to be fixed from entering the recesses of the ceramic layer or cermet layer. For example, only the concave portions of these layers may be filled with resin, and some of the convex portions of these layers may be exposed to the surface. Further, in this example, an undercoat layer is provided between the ceramic layer or the cermet layer, but the above layer may be provided for the purpose of improving the durability of the fixing roller. As the undercoat material, for example, N1-Cr gold alloy, Al-N1 alloy which causes thermite reaction, etc. can be used, and the thickness may be about 20 to 30 microns.

Next, the method of forming the ceramic layer or cermet layer and the method of forming the resin layer will be described in detail while explaining the method of manufacturing the fixing roller of this example.

First, the roller base is blasted. Preferred materials for the roller base include metals such as iron, stainless steel, iron alloys, aluminum alloys, and copper alloys, but ceramics such as alumina, boron nitride, silicon nitride, zirconia, and sialon can also be used. Next, an undercoat layer is formed by, for example, plasma spraying. Thereafter, a ceramic or cermet layer is formed.

Preferred methods for forming these layers include flame spraying, plasma spraying, and other thermal spraying methods.
Other plasma discharge, CVD, PVD.

Ion brating etc. can also be used. Preferred raw materials for forming the ceramic layer include powders of oxides such as alumina, titania, zirconia, ittria, and chromia, which have excellent abrasion resistance, or mixed powders thereof, and BN.

Nitride powder such as TIN or mixed powder thereof, Tic, si
A carbide powder such as C or a mixed powder thereof can also be used.

As raw materials for forming the cermet layer, metal powders such as Fe, Ni, Co, Cr, Cu, etc. or mixed powder thereof can be used as the metal material, and the above-mentioned raw materials for forming the ceramic layer can be used as the ceramic material. It is mentioned as a thing. These layers preferably have a thickness of about θo left to θ3rran.

Below 00, uneven formation may occur and a uniform layer may not be formed, and above θS■, these layers may peel.

Next, as a method for forming a ceramic layer or a cermet layer,
A specific example of a method using plasma spraying is shown below.

The plasma spraying device used was Meticore M.

The raw material powder for the ceramic layer or cermet layer is thermally sprayed onto the undercoat layer, and at this time the power is increased to increase the hardness of the thermally sprayed layer. That is, the current and voltage are respectively so.

Set it slightly higher than usual, such as mA or more and Ov or more. In particular, increase the current. However, the gas flow rate and gas pressure for plasma formation are also set accordingly.

Furthermore, in order to eliminate undissolved particles and increase the spray particle velocity when adhering to the workpiece, the distance between the workpiece and the gun was set at 70°.
Make it around 0. In addition, the rotation speed of the workpiece is
The gun feed speed should be set to about 7018 pm and slow to prevent uneven spraying.

Finally, a resin is coated on the ceramic layer or cermet layer. Preferred raw materials for coating include fluororesins such as PTFE (polytetrafluoroethylene) and PFA (perfluoroalcoholic acid), but silicone resin, silicone rubber, P
OM (polyoxymethylene) and the like can also be used. A preferred method for coating is a method in which a finely powdered coating of the above-mentioned raw material is sprayed onto the ceramic layer or cermet layer and then heated and melted. It is also possible to use a method in which a resin layer is deposited thickly in advance and then polished to a predetermined thickness. The resin does not necessarily have to form a layer to have the effect of preventing stains on the recording 4A, but it is preferable that the resin forms a layer, and the thickness of the resin is equal to that of the convex portion of the ceramic layer or cermet layer and the resin surface as shown in Fig. 3. Sμ~1 with a thickness of
Approximately 00μ is preferable. If it is less than sμ, a ceramic layer or a cermet layer will form on the surface of the fixing roller, making it easy for the fixation target to adhere, and the lubricating effect of the resin will be lost, resulting in poor wear resistance of the fixing roller. Also / 0
If it exceeds 0 lt, the effect of the uneven portions of the ceramic layer is lost and the matte effect is lost.

FIG. 3 shows a typical microstructure near the boundary between a ceramic layer or a cermet layer created by thermal spraying and a resin layer, and there are fine pores/3 near this boundary. Most of these holes are filled with resin, but not all of them are filled, leaving some holes at the bottom. This produces a microscopic matte effect, which has a synergistic effect with the macroscopic matte effect, and is highly effective in preventing the recording material from becoming glossy.

Therefore, a fixing roller on which a ceramic layer or a cermet layer is formed by thermal spraying is excellent in preventing the recording material from becoming glossy.

Below, the results of using the fixing roller of this embodiment, a conventional mirror-finished roller, and a matte roller with a rough surface in the fixing device shown in FIG. 1 and applying this to a copying machine will be shown, and the effects brought about by the present invention will be explained. .

In Table 1, the conventional mirror roller has good durability to some extent (0 to 300,000 sheets), but requires a large amount of pressure to improve fixing properties, causing gloss and curling on the paper surface. I'll put it away. In addition, although the conventional matt roller lacks durability and requires replacement in practice, the fixing effect is better than that of a mirror surface, and the copy paper is less glossy.

In contrast, in the present invention, the durability is 2 to 2 that of the mirror roller.
The fixing performance has been improved by 3 times, and sufficient fixing performance can be obtained with light pressure, with less gloss.

Furthermore, the resin layer that is releasable from the toner has a lubricating effect between the rollers, and together with the provision of the ceramic layer, the wear resistance of the fixing roller is improved. Furthermore, since the resin layer has the effect of preventing toner from being offset to the fixing roller, stains on copy paper are eliminated. Furthermore, the removability of the resin prevented problems such as copy paper wrapping around the roller.

Although the effects of the present invention have been illustrated using a copying machine as an example, stable fixing performance as described above can be achieved in all devices to which the fixing roller of the present invention is applied, such as other image recording devices and printing machines. Obtained over a long period of time.

Table / *Table that determines the lifespan when the surface becomes rough and toner offset becomes noticeable Consistent adhesion judgment results (initial) A: Good B: Average
C...Not possible

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of a fixing device using the fixing roller of the present invention, and FIG. 2 is a cross-sectional view of an example of the fixing roller of the present invention, taken along a plane including the rotation axis. FIG. 3 is a sectional view taken along line A-A' in FIG. 2, FIG. 9 is a partial sectional view of FIG. 2, and FIG. FIG. /... Fixing roller, 2... Pressure roller. 3...Upper side plate, Da...Lower side plate. S...Support shaft, A...Bolt. 7...Spring, g...Natsuto. 9...Resin layer. 10... Ceramic layer or cermet layer. //... Undercoat layer /2... Roller base, /3... Hole. Patent applicant Canon Co., Ltd. Figure 1-A Figure 2 @ Figure 3 Figure 5

Claims (1)

[Claims] il+ A recording material is passed between a fixing roller provided on the side that contacts the fixing material and a pressure means facing the fixing roller,
A pressure fixing roller of a fixing device that fixes a material to be fixed on a recording material by pressure has a ceramic layer or a cermet layer on the surface of the fixing roller, and the ceramic layer or the cermet layer has a property of being fixed and peelable. A pressure fixing roller characterized by being coated with a certain resin. (2) Claim 7, characterized in that the ceramic layer or the cermet layer is formed by a thermal spraying method.
The pressure fixing roller described in .