JPS6161189A - Pressure fixing roller - Google Patents

Abstract

PURPOSE:To prevent the generation of luster and contamination of a recording material, to raise the resistance to wear and the durability, and to obtain stable fixing performance by providing a mat-shaped anodized Al film on the surface of a base body of a fixing roller and/or a pressure roller, and coating said layer with a resin. CONSTITUTION:An anodized film (alumite layer) 12 of Al or an Al alloy having the mat-shaped surface is provided on the surface of a base material 10 of a fixing roller 1 or a pressure roller, or both of them of a fixing device for passing a recording material P through between the fixing roller provided on the side contacting a material to be fixed (toner image) T, and the pressure roller 2 opposed to said roller, and fixing the toner image T on said material by pressure, and also a coating 13 of a resin having a peeling property to the toner image is provided on the alumite layer 12. Also, it is desirable that an undercoat layer 11 is provided between the base mate rial 10 and the alumite layer 12. By constituting the fixing roller 1 in this way, the generation of luster of the recording material P can be prevented. Also, since the resin coating 13 has been provided, the adhesion of a toner is prevented and the record ing material P is not contaminated, and stable fixing performance is obtained over a long period of time.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a fixing roller of an image forming apparatus such as a printer, a copier, or a facsimile machine, or a fixing device of a printing press. This relates to a pressure fixing roller used in a pressure fixing device that passes a recording material between a fixing roller provided on the fixing side and a pressure means facing the fixing roller, and fixes the material to be fixed on the recording material by pressure. It is.

[Background of the invention]

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, copying machines generally use steel fixing rollers with mirror-finished surfaces, but in order to fix toner images on copy paper, it is necessary to apply an average linear load of 20 kg/cm or more. there were.

However, when a pressure of 12 kVCIn or more is applied, the problem that the covey paper becomes smooth and becomes glossy and folds cannot be avoided.

In order to solve this problem, the surface of the fixing roller is subjected to induction hardening, hard Cr plating, etc. to increase the surface hardness and extend the life of the roller, and at the same time, the surface of the fixing roller is treated to be matte. Matte treatment is a method of blasting the surface of the fixing roller to give the surface matte-like unevenness, thereby giving unevenness to the copy paper and preventing it from becoming glossy.

However, in the above method, (1) Greater pressure is applied to the convex portions of the matte-treated fixing roller than to the concave portions, resulting in severe wear, and the matte surface disappears and the copy paper immediately becomes glossy.

(2) Problems arise in that toner enters the mat recesses and is retransferred, staining the copy paper, or that the toner that enters the matte removes the toner on the paper.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to prevent the occurrence of gloss on recording materials, prevent stains on recording materials, and further improve wear resistance and durability. It is an object of the present invention to provide a pressure fixing roller that can provide stable fixing performance over a long period of time.

[Summary of the invention]

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. In this fixing roller, a positive oxide film (hereinafter referred to as an alumite layer) of aluminum or aluminum alloy having a matte surface is applied to the substrate surface of both the fixing roller and the roller used as a pressure means. The fixing roller is characterized in that the alumite layer is provided with a resin coating that is removable from the fixing material on the alumite layer.

[Embodiments of the invention]

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.

FIG. 1 shows a pressure fixing device equipped with a fixing roller according to the present invention.
A recording material (paper P in the illustrated example) is passed between the recording material and a pressure roller 2, which is a pressure means, facing the recording material, and the fixing material (toner image T) on the recording material is fixed by pressure. The above rollers 1 and 2 are fixing rollers according to the present invention, and each include roller bases 1/, 2/, alumite layers 1///, 2///, and resin coating layer 1''.
, 2".

The fixing roller 1 and the pressure roller 2 are rotatably supported at both ends by an upper plate 3 and a lower plate 4, respectively.

The upper plate 3 and the lower plate 4 are rotatably connected at one end by a support shaft 5, and at the other end, the upper plate 3 and the lower plate 4
111 board 3.4, Del Toro that penetrates this, applicable? The pressing force ω is applied by the functions of three members: a spring 7 provided around the root 6, and a nut 8 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 1 and the pressure roller 2, the average linear load obtained by dividing W by the roller length is 20 to 50 kg/ crn). This load w acts directly on the plain paper P supporting the toner image T,
The toner image T on the surface is fixed under pressure.

The fixing roller 1 is rotationally driven in the direction of the arrow by a motor (not shown) via a gear (not shown) provided at an end thereof.

Pressure roller 2 is moved upward in the direction of the arrow by frictional force (by roller 1 when paper P is pushed between rollers 1 and 2, and by paper P when paper P is pressed between rollers 1 and 2). Rotate to . Due to the rotation of both rollers 1 and 2, the paper P advances in the direction of the arrow, and the pressure fixing action of the toner image T is achieved.

The details of one embodiment of the Takiri fixing roller according to the present invention will be explained in the second section.
As shown in FIG. The illustrated fixing roller has an undercoat layer 11 on a roller base 10, and an anodic oxide film layer of aluminum or aluminum alloy (
An alumite layer) 12 is provided, and on this alumite layer,
A coating 13 of resin that is removable from the fixing material (toner) is provided.

The alumite layer 12 has a matte surface as shown in FIG. 4, which prevents the recording material from becoming glossy. Further, by filling the recesses of the alumite layer 12 with the resin layer, the material to be fixed is prevented from entering the recesses of the alumite layer 12, thereby preventing staining of the recording material. In this example, the coating state of the resin is a resin layer, but it does not necessarily have to be a resin layer, and any state that can prevent the material to be fixed from entering the four parts of the alumite layer 12 is sufficient. 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. In the illustrated example, an undercoat layer is provided between the roller base 10 and the alumite layer 12, but this is provided for the purpose of improving the durability of the fixing roller, and is not necessarily required. It's okay. As the undercoat material, for example, N
An i-Cr alloy or an A/=-N1 alloy that causes a thermite reaction can be used, and the thickness may be about 20 to 30 microns.

Next, the method of forming the alumite 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 roller base materials 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. After that, an aluminum layer or an aluminum alloy layer is formed. Preferred methods for forming these layers include thermal spraying methods such as flame spraying and plasma spraying. Preferably, these layers have a thickness of about 0.005 to 0.5 ut. Below 0.05 mm, uneven formation may occur and a uniform layer may not be formed;
At 5III+1 or more, peeling of these layers may occur.

Next, as a method for forming the alumite layer, one method using plasma spraying will be shown below as a specific example. The plasma spray equipment used was Meticore M (trademark).

The raw material powder for the aluminum layer or aluminum alloy layer is thermally sprayed onto the undercoat layer.
At this time, increase the temperature by 1,000 watts to increase the confidentiality of the sprayed layer. In other words, the current and voltage should be 500 mA or more, respectively.
Normally, the voltage should be set slightly higher than 0v. In particular, increase the current. However, the gas flow rate and gas pressure for plasma formation are set higher accordingly. Furthermore, the distance between the workpiece and the gun is set to around 100s+s+ in order to eliminate undissolved particles and increase the spraying particle velocity when adhering to the workpiece. In addition, it is preferable to set the rotational speed of the workpiece as high as about 60 rpm and to slow the gun feed speed to about 10 tm78 to avoid uneven spraying.

The aluminum or aluminum alloy layer thus formed is then anodized.

There are various methods for producing hard anodic oxide films, such as (1) constant DC current density method, (2) constant constant current force method, and (3) constant AC/DC superposition method, but the following four things should be noted. There are many. ○ Electrolysis temperature 10℃ or less 0 Current density (in case of DC electrolysis) 2 to 10 A/dm20 Sulfuric acid electrolyte concentration 20 to 40
Remove and cool the electrolyte to a certain degree.

Finally, coat the alumite layer with resin. Preferred raw materials for coating include fluororesins such as PTFE (polytetrafluoroethylene) and PFA (iR-fluoroalkoxy), but silicone resin, silicone rubber, and POM (polyoxymethylene) are also used. It is possible. A preferred method for coating is a method in which fine powder of the above-mentioned raw material is sprayed onto the alumite 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 material, but it is preferable that the resin forms a layer, and the thickness of the resin
The thickness of the convex part of the alumite layer and the resin surface shown in the figure is 5μ to 10
Approximately 0μ is preferable. If it is less than 5μ, an alumite layer will form on the surface of the fixing roller, making it easier for the material to be fixed to adhere.
The lubricating effect of the grooved resin is lost, and the wear resistance of the fixing roller becomes poor. Moreover, if it is more than 100 μm, the effect of the uneven portions of the alumite layer becomes so strong that the matte effect is lost.

FIG. 5 shows a typical microstructure near the boundary between the alumite layer and the resin layer created by thermal spraying, and there are fine pores 14 near this boundary. Most of these holes are filled with resin, but not all of them are filled, and there are some holes at the bottom!
! , is left behind. The stiffness 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 having a layer formed by anodizing aluminum or an aluminum alloy using a thermal spraying method is excellent in preventing gloss from forming on the recording material.

Below, we will show the results of using the fixing roller of the above embodiment, the conventional Q-side roller, and the rough-surface matte roller in the fixing device shown in FIG. explain.

Table 11 In Table 2, the conventional mirror roller has good durability to some extent (200,000 to 300,000 sheets), but requires a large amount of pressure to improve fixing properties, resulting in gloss and curling on the paper surface. . Further, although the conventional matt roller has poor durability and requires many replacements in practice, the fixing effect is better than that of a mirror surface, and the copy paper is a little glossy.

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

The thin toner and removable resin layer have a lubricating effect between the rollers, and together with the provision of the alumite 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. -! The removability of the resin also prevented problems such as copy paper wrapping around the roller.

Table 1 Durability of fuser roller Connecting roller diameter φ57) A4 size medium The life is determined when the surface becomes rough and toner offset becomes noticeable Table 2 Fixability judgment results (initial) A...Good B...fair
C... Not possible In the present invention, the fixing roller itself may be entirely made of aluminum or aluminum alloy and may be anodized, but aluminum or aluminum alloy has a side column that has a Young's modulus of 1 compared to iron-based alloys. /3, so the roller diameter must be larger than that for iron-based alloys. Alternatively, the core material of the roller may be made of iron and the outer peripheral portion may be made of aluminum or an aluminum alloy, but this increases the number of parts.

Below, the effects of the present invention will be illustrated using a copying machine as an example14.
) However, in all devices to which the fixing roller of the present invention is applied, such as other image recording devices and printing machines, stable fixing performance as described above has been obtained over a long period of time.

〔Effect of the invention〕

As described above, the fixing roller according to the present invention prevents the recording material from becoming glossy due to fixing by the action of the matte surface of the hard alumite layer provided on the surface of the roller base. However, since the surface of this hard alumite layer is coated with a resin that is removable from the material to be fixed, the material to be fixed may enter the recesses of the mat and contaminate the recording material. In addition, the abrasion resistance and durability of the roller are also improved, and stable fixing performance can be obtained over a long period of time. However, on top of the above hard alumite layer,
Even if the resin is coated uniformly, the hard alumite layer inside will have a strong effect, and a sufficient matte effect will not be obtained.
The effect of preventing the recording material from becoming glossy can be achieved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of a fixing device using the fixing roller of the present invention, FIG. 2 is a cross-sectional view of an example of the fixing roller of the present invention cut along a plane including the rotation axis, and FIG. A in Figure 2
-A' sectional view, FIG. 4 is a partial sectional view of FIG. 2, and FIG. 5 is a sectional view of an anodized portion of aluminum or aluminum alloy obtained by a thermal spraying method in an example of the fixing roller of the present invention. be. 1: Fixing roller 2: Pressure roller 3: Upper plate
4: Lower plate, 5: Support shaft, 6: ? 7: Spring, 8: Nut, 10: Roller base, 11: Undercoat layer, 12: Alumite layer, 13: Resin layer, 14: Hole.

Claims (1)

[Scope of Claims] A fixing method in which a recording material is passed between a fixing roller provided on the side that contacts the fixing material and a pressure means facing the roller, and the fixing material on the recording material is fixed by pressure. In the pressure fixing roller of the apparatus, an anodic oxide film layer of aluminum or aluminum alloy having a matte surface is provided on the surface of the base of the fixing roller, the roller used as a pressure means, or both, and this anode A pressure fixing roller characterized in that a resin coating that is releasable from the fixing material is provided on the oxide film layer.