JPH0535140A - Production of fixing roller - Google Patents

Abstract

PURPOSE:To eliminate the need for polishing or further rebaking after application of a fluororesin on a roller core body and to allow the uniform application of a fluororesin dispersion over the entire area of the coating surface of the roller core body in coating of a fixing roller with the fluororesin dispersion. CONSTITUTION:This method for coating the roller core body 3 with the fluororesin dispersion consists in supplying the fluororesin dispersion 2 onto the front surface of a resin dispersion tank 1 to put the fluororesin dispersion 2 into the state of being built up by surface tension, then bringing the core body 3 closer to the resin dispersion tank 1 up to the spacing at which this fluororesin dispersion 2 can be picked up, rotating the core body 3 to pick up the desired fluororesin dispersion 2 and moving the core body 3 to the side parting from the resin dispersion tank 1 to disconnect the core body 3 and the resin dispersion tank 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a fixing roller used in a fixing section of a copying machine, a line printer, a facsimile, etc.

[0002]

2. Description of the Related Art A fixing unit of a copying machine or the like is usually constructed as shown in FIG. 4, and a copy paper 33 on which toner 32 is transferred is passed between a heat fixing roller 30 and a pressure fixing roller 31. A method of fixing an image on copy paper by heat (usually 170 ° C. to 200 ° C.) and pressure is generally adopted in terms of safety and economy.

In this case, as the heat fixing roller 30,
A roller base material made of a metal such as aluminum, ceramics, or heat-resistant plastic, that is, a surface of a roller core body 34, which is coated with a fluorine resin for several tens of μm in order to improve the releasability of the toner (the coating portion is indicated by 35). Is used. In FIG. 4, 36 is a roller core, 37 is a pressure fixing roller pulling coating, 38 and 39 are separation claws, 40 is a fixed image, and 41 is a heater.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Dispersion of fluororesin in a roller core (hereinafter simply abbreviated as core) having a circular cross-sectional outer circumference of aluminum, aluminum alloy, metal such as iron, ceramic, heat-resistant plastic, etc. Transfer coating is a method of coating a liquid. Transfer coating is a method in which the transfer coating roll rolls up the paint in the liquid tank and transfers the rolled-up paint to the core to apply it. However, since the core does not wind up the paint directly from the liquid tank, it is applied to the coated surface. The unevenness occurs. Since the width of the core that can be coated is determined by the length of the transfer coating roll, a transfer coating roll is required each time the coating width of the core changes, which increases equipment costs.

On the other hand, in the methods of spray coating and electrostatic coating,
The roughness of the resin surface after baking the fluororesin is large when it is painted, and it is necessary to finish the surface by polishing. In some cases, the polished one is re-baked (the scratch on the resin surface is removed by re-baking). There is a need.

On the other hand, in the case of coating according to the present invention, since the core directly winds up the resin dispersion liquid that has risen on the upper surface of the resin dispersion liquid tank, unevenness does not occur on the coating surface and the coating width of the core is It can be determined by the width of the liquid tank. With this coating, a uniform and smooth resin surface without undulations can be obtained on the surface of the resin after baking the fluororesin, so that polishing and rebaking are not required.

However, when the connection between the fluororesin dispersion liquid on the upper surface of the resin dispersion liquid tank and the fluororesin dispersion liquid on which the core is wound up on the outer peripheral surface is cut off, the coating amount increases, that is, the resin thickness becomes thick. It is difficult to apply the resin dispersion liquid evenly over the entire surface of the core body to be coated.

Specifically, the difference in resin thickness between the portion where the coating amount is large and the portion where the coating amount is not large may be 30 μm or more, and when used as a fixing roller of a copying machine, the image fixing property is partially reduced. Poor, wrinkles appear on the copy paper, and the resin surface may have light and shade in areas where the amount of coating is large and areas where it is not applied, or streaks may appear, which may cause problems in appearance.

In view of the above, the present invention provides a method for manufacturing a fixing roller for coating a core body with a dispersion liquid of a fluororesin which solves the above problems.

[0010]

A method of manufacturing a fixing roller according to the present invention comprises a core made of aluminum, aluminum alloy, metal such as iron, ceramic, heat-resistant plastic, etc., having a circular cross-section circular core, and a fluorine resin. In the method for coating the dispersion liquid, a fluororesin dispersion liquid is applied to the upper surface or above of the resin dispersion liquid tank by using a coating device equipped with a resin dispersion liquid tank, a drive system for rotating the core body, and a transporting unit for the core body. The supplied fluororesin dispersion is in a state of being raised due to surface tension, and the core is brought close to the resin dispersion tank until an interval (hereinafter referred to as a gap distance) at which the fluororesin dispersion can be rolled up, After the desired fluororesin dispersion liquid is wound up by rotating, the core is moved to the side away from the resin dispersion tank and the core and resin dispersion are separated to coat the core with the fluororesin dispersion liquid. The features.

Note that at least the following is included as an embodiment of the present invention. (B) When the core is moved away from the resin dispersion tank to separate the core and the resin dispersion, the fluororesin dispersion that is in contact with both ends of the effective coating width of the core moves inside. Using a coating device with a thin plate to prevent the fluororesin dispersion liquid from moving inward when the core body is wound up with the desired fluororesin dispersion liquid and then moved away from the resin dispersion liquid tank. And a method of manufacturing the fixing roller according to the present invention, wherein the core body is coated with the fluorine resin dispersion liquid by separating the resin dispersion liquid from the core body when the gap distance reaches a predetermined distance. .

(B) The viscosity of the fluororesin dispersion liquid is 10 to 20.
The method for producing a fixing roller according to the present invention is characterized in that it is 0 cp.

(C) The fluororesin in the fluororesin dispersion liquid is composed of polytetrafluoroethylene (hereinafter abbreviated as PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA), or PTFE and PFA. PTFE or P containing a mixture or organic polymer
The fixing roller manufacturing method according to the present invention, which is FA or a mixture of PTFE and PFA.

(D) Pigments and fluorine for coloring containing 1 wt% or more of an organic polymer (acrylic resin, polyamideimide, polyimide, polyphenylene sulfide, polyether sulfone, etc.) for improving the adhesiveness to the roller core. When coating an aqueous dispersion containing resin such as PTFE (hereinafter abbreviated as a primer dispersion) on the core, a desired weight of fluororesin dispersion is rolled up and the gap distance at that time is separated when separating the transfer coating roll from the core. The fixing roller manufacturing method according to the present invention is characterized in that the length is 2 mm to 20 mm.

(E) An aqueous dispersion of a fluororesin (hereinafter abbreviated as PTFE for top) containing 20 to 70 wt% of PTFE or 0.2 to 5 wt% of a filler and further containing a coloring pigment is used as a core. At the time of coating, the fluororesin dispersion liquid of the desired weight is rolled up, and when the transfer coating roll and the core are separated, the gap distance at that time is 2 mm to 30 mm.
The method for manufacturing a fixing roller according to the present invention, wherein

(F) 20% tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA)
When coating an aqueous dispersion of a fluororesin containing up to 70 wt% (hereinafter abbreviated as top dispersion (PFA)) onto a core, and winding up a desired weight of the fluororesin dispersion to separate the transfer coating roll from the core The distance between the gaps at that time is 2 mm ~
The fixing roller manufacturing method of the present invention is characterized in that it is 30 mm.

The present invention will be described in detail below. Figures 1-3
FIGS. 1A and 1B are views for explaining a method of manufacturing a fixing roller according to the present invention. FIG. 1 is a front view of the whole, and FIGS. 2 and 3 are fluorine particles which are raised in a resin dispersion tank by a surface tension of a fluorine resin dispersion liquid. A front view (FIG. 2) and a side view (FIG. 3) are respectively illustrated in an explanatory view of a state where the resin dispersion liquid is wound up by the core body.

In these figures, 1 is a resin dispersion liquid tank, 2 is a resin dispersion liquid, 3 is a roller core, 4 is a drive system for rotating the core, 5 is a core transport mechanism, 6 is a thin plate, Reference numeral 7 denotes a dispersion liquid temperature adjusting device. In order to keep the temperature of the dispersion liquid constant, control the viscosity of the dispersion liquid, and stabilize the coating amount of the dispersion liquid, it is necessary to provide a dispersion liquid temperature control device. For example, a tank that covers the entire dispersion tank is prepared, cooling water is passed through the tank to cool the dispersion, and the viscosity is controlled.

In order to solve the above-mentioned problems of the prior art, it is necessary to adjust the coating method, preferably the coating conditions such as the viscosity of the fluororesin dispersion liquid. That is, 1) The difference in resin thickness between a thick resin portion and a thick resin portion, which is generated when the fluororesin dispersion liquid in the resin dispersion liquid tank and the fluororesin dispersion liquid wound on the outer peripheral surface of the core are cut off, It is necessary to optimize the method for cutting off the fluororesin dispersion in order to make it small, especially less than 30 μm. At this time, it is necessary to determine the optimum method in consideration of the physical properties of the fluororesin dispersion liquid (viscous resistance, capillary phenomenon, surface tension, etc.).

As a result of diligent examination of this, the present inventor has found that the following method is effective. Using a coating device, the outer peripheral surface of the core body winds up the fluororesin dispersion liquid that has risen due to the surface tension of the dispersion liquid on the resin dispersion liquid tank (the distance between the core body and the resin dispersion liquid tank) (hereinafter the gap distance). Abbreviated) until the core is brought close to the resin dispersion tank and the desired amount of coating is wound on the outer peripheral surface of the core, and then the distance between the gaps is increased. To prevent the fluororesin dispersion liquid that is in contact with both ends of the effective coating width (the length in the longitudinal direction of the part where the fluororesin dispersion liquid is required to be applied) from moving inward, When the movable thin plate is attached and the core is moved away from the resin dispersion tank, the resin dispersion tank,
It was found that the resin dispersion liquid tank and the core can be effectively separated by expanding the gap distance until the thin film formed by the surface tension of the coating is cut between the thin plate on the side of the resin dispersion liquid tank and the core. It was

2) The viscosity of the fluororesin dispersion is usually 200.
There are 3 types when they are roughly classified into ~ 300 cp. There are three types of primer dispersions used to enhance the adhesion between the core and the fluororesin (composition is 1 wt% or more organic polymer material for enhancing the adhesion. For example, acrylic resin, polyamide imide, polyimide, polyphenylene sulfide, polyether sulfone, etc., color pigments and fluororesin solids, and surfactants for dispersing these in water.
The fluororesin solids are PTFE, PFA or a mixture of PTFE and PFA. )

PTFE for the top which has a function as a fixing roller by coating on the primer layer (composition: 2
PTFE of 0 to 70 wt% and 0.2 to 5 wt% of filler for improving various properties after film formation depending on the case. Further, what needs to be colored is a coloring pigment, and these are dispersed in water. Is a surfactant for. )

A top PFA (having a composition of 20) that is coated on the primer layer to function as a fixing roller.
˜70 wt% PFA and a surfactant for dispersing this in water. ).

When coating these, it is difficult to obtain a desired resin thickness if transfer coating is performed with this viscosity being maintained. Further, the fluororesin dispersion liquid wound on the outer peripheral surface of the transfer coating roll and the outer peripheral surface of the core are coated. There is a large difference in the resin thickness between the thick resin portion and the thick resin portion when the wound up fluororesin dispersion liquid is cut off, and it is difficult to reduce this difference. Becomes
In order to improve this, it has been found that it is necessary to adjust the viscosity of the fluororesin dispersion liquid to 10 to 200 cp, and more preferably 20 to 80 cp.

The viscosity of the fluororesin dispersion liquid is adjusted by using, for example, pure water or a viscosity-adjusting surfactant. As described above, the fluororesin dispersion liquid is applied uniformly, and the difference between the thick resin portion and the thick resin portion that occurs when the core body is moved away from the transfer coating roll is reduced to reduce color unevenness. Is preferably 1) above,
It was found that the combination of 2) can be achieved.

[0026]

[Function] A fluororesin dispersion liquid is supplied above the upper surface of the resin dispersion liquid tank by using a coating device equipped with a resin dispersion liquid tank, a drive system for rotating the core body, and a core transport mechanism section. Keep the swelling due to the surface tension, bring the core to the resin dispersion tank until the fluororesin dispersion can be wound up, and rotate the core to wind up the desired fluororesin dispersion. After that, the core can be coated with the fluororesin dispersion by moving the core away from the resin dispersion tank and separating the core from the resin dispersion.

When the fluororesin dispersion liquid in the resin dispersion liquid layer and the outer peripheral surface of the core are in contact with each other with a certain gap distance, when the contact is cut off, the core is expanded when the gap distance is increased. When the fluororesin dispersion liquid contacting both ends of the effective coating width of the body (the length in the longitudinal direction of the portion where the fluororesin dispersion liquid needs to be coated) is moved inward, the thin plate on the side surface of the resin dispersion liquid tank By providing a thin film formed by the surface tension of the fluororesin dispersion liquid between the resin dispersion liquid tank, the thin plate provided on the side surface of the resin dispersion liquid tank, and the core, the gap distance is enlarged until the thin film is cut. By removing the thin plate provided on the side surface of the resin dispersion liquid tank while the gap distance is being increased, the fluororesin dispersion liquid wound around the outer peripheral surface of the core metal and the fluororesin dispersion liquid in the resin dispersion liquid tank When is cut Can the amount of fluorine resin dispersion that extra wound up on the outer peripheral surface of the core to minimize the results fluororesin dispersion is often part and Otherwise part of the difference in resin thickness and can be minimized.

The viscosity of the fluororesin dispersion is preferably 1
The above-mentioned effects can be obtained more preferably when it is 0 to 200 cp, and more preferably 20 to 80 cp. When the viscosity of the fluororesin dispersion exceeds 200 cp, the difference in resin thickness may exceed 30 μm, which causes a problem in appearance, and when it is less than 10 cp, a resin film that can be used practically cannot be obtained.

As described above, the difference in resin thickness can be minimized by optimizing the viscosity of the fluororesin dispersion liquid and the like in the coating method. The present invention is not limited to the fixing roller but can be applied to all rollers having a cylindrical surface coated with a fluororesin paint.

[0030]

EXAMPLES Examples of the present invention will be described below. Example 1 A dispersion having various viscosities was prepared for each fluororesin dispersion (composition will be described later) by transfer coating according to the present invention on an aluminum core metal (core) having an outer diameter of 25 mm, and each dispersion had a predetermined resin thickness. The coating conditions (core rotation speed) are adjusted so that the core can be obtained, the conditions for keeping the core away from the resin dispersion tank are constant, each dispersion is coated, and baked for 30 minutes at a temperature of 380 ° C for evaluation. A sample was prototyped. Evaluation of sample is based on resin thickness difference {(maximum diameter of resin thickness)
-(Minimum diameter of resin thickness)}.

Table 1, Table 2 and Table 3 show the evaluation results and the conditions for moving the core metal away from the resin dispersion liquid tank. The composition of the fluororesin dispersion liquid used is as follows.

1. Primer dispersion: 1 wt% polyamide imide, 20 wt% PTFE

2. Top dispersion (PTFE): 0.2
wt% filler 50 wt% PTFE

3. Top dispersion liquid (PFA): 50 wt
% PFA

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

Example 2 The viscosity of each fluororesin dispersion liquid (the composition is the same as in Example 1) was set to 1 by transfer coating according to the present invention on an aluminum cored bar having an outer diameter of 25 mmφ.
Adjust the coating condition (core rotation speed) so that a predetermined resin thickness is obtained, and set the condition (distance between gaps) when moving the core away from the resin dispersion tank. The coating liquid was applied under these conditions and baked for 30 minutes at a temperature of 380 ° C. to prepare a sample for evaluation. The evaluation of the prototype was performed on two items: variation in resin thickness and appearance of coated surface. The respective conditions and evaluation results are shown in Table 4, Table 5, Table 6, Table 7, Table 8, Table 9, Table 10, Table 11 and Table 12.

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Table 7]

[0043]

[Table 8]

[0044]

[Table 9]

[0045]

[Table 10]

[0046]

[Table 11]

[0047]

[Table 12]

The evaluation was performed according to the following criteria. Variation in resin thickness After coating and baking the fluororesin dispersion on the roller core, measure the resin thickness at 8 points in the circumferential direction and 5 points in the axial direction for a total of 40 points (maximum value of resin thickness)-(minimum value of resin thickness) ) / (Average resin thickness) was used to evaluate the variation in resin thickness.

Appearance of Painted Surface After coating and baking the fluororesin dispersion liquid on the roller mandrel, the appearance of the painted surface of the mandrel was evaluated.

As in Example 2, the rotational speed of the transfer coating roll and the rotational speed of the cored bar were adjusted to raise the cored bar so that the viscosity of each fluororesin dispersion was 10 to 200 cp and a predetermined resin thickness was obtained. It was found that by setting the distance between the gaps at the time as follows, a coated article having a good resin thickness balance and good appearance can be obtained.

Primer dispersion (gap distance) 2
~ 20mm Top dispersion PTFE (gap distance) 2-30
mm Top dispersion PFA (distance between gaps) 2 to 30 m
m

Example 3 and Comparative Example A transfer coating and spray coating were used to coat and burn a fluororesin dispersion (using the same primer dispersion and top dispersion (PFA) composition as in Example 1) on the roller core metal. Then, the spray-painted product was polished to finish the surface roughness of the painted surface. After measuring the surface roughness of each coated baked product, it was mounted on a copy machine and evaluated on an actual machine. The evaluation was judged by the dirt of the cleaning pad of the roller core metal. The results are shown in Table 13.

[0053]

[Table 13]

In the case of spray coating which is a conventional coating method, the surface roughness of the coated surface is as high as 3.5 S without polishing, and even when the surface roughness is finished to 0.5 S by polishing, Micro scratches on the painted surface after polishing,
Alternatively, microscopic fluffing occurred, so good results could not be obtained in the actual evaluation, and it was necessary to re-fire after polishing. However, in the case of transfer coating, it was found that good results could be obtained without polishing and rebaking.

[0055]

As described above, according to the present invention, since transfer coating is carried out in coating the fixing roller with the fluororesin dispersion liquid, the roller core body is coated with the fluororesin like spray coating or electrostatic coating. After that, there is no need for polishing or further rebaking. Moreover, it is possible to uniformly coat the fluororesin dispersion liquid on the entire coated surface of the roller core body.

[Brief description of drawings]

FIG. 1 is a schematic side view showing the coating according to the present invention.

FIG. 2 is a partial schematic side view during transfer coating, which is an explanatory view of coating according to the present invention.

FIG. 3 is a schematic front view of a main part at the time of coating, which is an explanatory view of coating according to the present invention.

FIG. 4 is an example of a side view for explaining a use state of a fixing roller.

[Explanation of symbols]

1. Resin dispersion tank 2. Resin dispersion 3. Roller core 4. Drive system that rotates the core 5. Core body transport mechanism 6. Thin plate 7. Dispersion temperature controller

Claims (7)

[Claims] 1. Aluminum, aluminum alloy,
In a method for coating a fluororesin dispersion liquid on a core body having a circular cross-section outer peripheral surface made of metal such as iron, ceramic, heat-resistant plastic, etc., a resin dispersion liquid tank, a drive system for rotating the core body, and a core body It is possible to roll up the fluororesin dispersion by supplying it with the surface of the resin dispersion tank above the upper surface of the resin dispersion tank by using a coating device equipped with a transport mechanism to make the fluororesin dispersion rise due to surface tension. Bring the core closer to the resin dispersion liquid tank up to the interval (hereinafter referred to as the gap distance), wind up the desired fluororesin dispersion liquid by rotating the core, and then move the core body away from the resin dispersion liquid tank. A method of manufacturing a fixing roller, characterized in that the core body is coated with a fluororesin dispersion liquid by moving the core body and separating the resin dispersion liquid. 2. When the core is moved away from the resin dispersion tank and the resin dispersion is separated from the core, the fluororesin dispersion which is in contact with both ends of the effective coating width of the core moves inward. Using a coating device with a thin plate to prevent the core from rolling up the desired fluororesin dispersion, and then moving the core away from the resin dispersion tank, the fluororesin dispersion moves inward. 2. When the gap distance reaches a predetermined distance, the core body and the resin dispersion liquid are separated to coat the core body with the fluororesin dispersion liquid.
A method for manufacturing the fixing roller described above. 3. The viscosity of the fluororesin dispersion liquid is 10 to 200 c.
The fixing roller manufacturing method according to claim 1, wherein the fixing roller is p. 4. The fluororesin in the fluororesin dispersion is polytetrafluoroethylene (hereinafter abbreviated as PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA), or PTFE and PF.
PTFE, PF containing mixture of A or organic polymer
The method for producing a fixing roller according to claim 1, wherein the fixing roller is A or a mixture of PTFE and PFA. 5. A pigment for coloring and a fluororesin containing 1 wt% or more of an organic polymer (acrylic resin, polyamideimide, polyimide, polyphenylene sulfide, polyether sulfone, etc.) for improving the adhesiveness to a roller core. For example, when coating an aqueous dispersion containing PTFE (hereinafter abbreviated as a primer dispersion) on a core, and winding up a desired weight of a fluororesin dispersion to separate the transfer coating roll from the core, the gap distance at that time is 2 mm. The method of manufacturing a fixing roller according to claim 1, wherein the fixing roller has a thickness of 20 mm. 6. An aqueous dispersion of a fluororesin containing 20 to 70 wt% of PTFE or 0.2 to 5 wt% of a filler and further containing a coloring pigment (hereinafter referred to as top dispersion PT).
When coating a core body with (FE) (abbreviated as FE) and winding up a desired weight of the fluororesin dispersion liquid to separate the transfer coating roll from the core body, the gap distance at that time is 2 mm to 30 mm. 1. The method for manufacturing a fixing roller according to 1. 7. A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) containing 20 to 7
At the time of coating an aqueous dispersion of fluororesin containing 0 wt% (hereinafter abbreviated as top dispersion (PFA)) on the core, at the time of winding up a desired weight of the fluororesin dispersion and separating the transfer coating roll from the core. The gap distance is 2 mm to 30
The fixing roller manufacturing method according to claim 1, wherein the fixing roller has a diameter of mm.