JP2001117404A - Image forming device having fixing roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device having fixing roller with which sandblast powders can be prevented from being mixed into a releasing layer, a bearing part can be prevented from being contaminated and both releasing property and fitting of the bearing part can be made satisfactory. SOLUTION: In the image forming device having a fixing roller 10 provided with a paper passing part 11 of a thick diameter for passing a recording paper, on which a toner image is formed, and bearing parts 12 of a thin diameter provided at both the ends of the paper passing part 11, grooves 11a for inserting masks for surrounding the outer peripheries of the bearing parts 12 are formed on both end faces 11b of the paper passing part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to an image forming apparatus having a fixing roller using an electrophotographic process such as a facsimile and a printer.

[0002]

2. Description of the Related Art FIGS. 6A and 6B show a fixing device provided in a conventional image forming apparatus, wherein FIG. 6A is a front view and FIG. 6B is a side view. As shown in FIGS. 6A and 6B, a fixing device provided in a conventional image forming apparatus includes a fixing roller 11 rotatably supported by a driving gear 122 via a bearing 121.
0, and a pressure roller 20 that presses and follows the recording paper P on which the toner 125 adheres together with the fixing roller 110. Reference numeral 21 denotes a bearing that rotatably supports the pressure roller 20.

As shown in FIG. 6B, a heating source such as a halogen lamp 123 is provided on the inner surface of the fixing roller, and the fixing roller 110 is controlled at about 180 ° C. By passing the recording paper P on which the unfixed toner 125 is placed through a nip portion 124 which is a contact portion between the heated fixing roller 110 and the pressure roller 20, the fixing roller 110
5 has a function of being fused and pressed to fix 126 on the recording paper P. The fusion bonding of the toner is performed in the nip 124.

When the paper passing speed of an electrophotographic apparatus having such a fixing device is increased, the passing speed of the nip 124 is also increased, so that the toner is not sufficiently melted. For this reason, generally, the fixing roller 110 and the pressure roller 2
The nip width is increased by increasing the outer diameter of the paper passing portion of zero. The nip width is the width in the paper passing direction of the nip 124 that is the contact portion between the fixing roller 110 and the pressure roller 20.

Therefore, the outer diameter of the paper passing portion of the fixing roller 110 and the outer diameter of the pressure roller 20 increase according to the speed of the paper passing speed. However, the bearing portion of the fixing roller 110 is generally φ30 mm from the cost merit due to unification of parts.
The following are used: For this reason, both ends of the cylindrical tube having the outer diameter of the paper passing portion serving as the bearing portion are squeezed to match the diameter of the bearing 121. Such an outer shape of the fixing roller will hereinafter be referred to as an aperture shape.

FIG. 7 is a view schematically showing the processing steps of the fixing roller. As shown in FIG. 7, first, in the cutting step S1, the core metal is dimensioned by cutting the entire length, the paper passing portion, and the outer diameter of the bearing portion.

Next, in the sandblasting step S2,
The paper passing part is sandblasted to increase the adhesion to the primer by the surface area effect and the anchor effect. Next, in the primer coating step S3, in order to increase the adhesion between the fluororesin film and the core metal, the wet primer is spray-coated on the paper passing portion, and dried after coating.

Next, in a fluororesin coating step S4, a dry (powder) or wet (liquid) fluororesin paint is applied to the paper passing portion. Next, in the firing step S5, 320 to 390 ° C.
And then melt the fluororesin to form a fluororesin film.

Next, in the polishing (finishing) step S6, since the fluororesin has poor thermal fluidity, the surface after firing has irregularities. This is removed by polishing to smooth the fluororesin surface.

As described above, in the processing step of the fixing roller, the surface of the core metal of the paper passing section is subjected to a sandblasting step, a primer coating step, and a fluororesin coating step in order to cover the paper passing section of the fixing roller with the release layer. However, the bearing portion is masked during processing so that sandblast powder and paint do not adhere after the cutting process.

FIGS. 8A and 8B are views showing a state in which a mask is mounted on a fixing roller of a conventional image forming apparatus, wherein FIG. 8A shows a state before mounting and FIG. 8B shows a state after mounting. As shown in FIG. 8, when mounting the conventional mask 114, the mask 114 corresponding to the outer diameter of the bearing 112 of the fixing roller 110 is attached to the bearing 112.
It just fits in. Reference numeral 113 denotes the mask 1
It is a center used when 14 is mounted.

[0012]

However, in the case of the conventional method, there is a problem that sandblast powder or fluororesin paint enters through the gap between the end face of the paper passing portion and the end face of the mask. When sand blast powder enters, sand blast powder is mixed into the release layer surface of the paper passing part in the subsequent fluororesin coating step and baking step, and the release property of the release layer deteriorates, causing toner sticking etc. .

Further, when the fluororesin paint enters, the fluororesin adheres to the bearing portion 112, so that when the fluororesin paint is inserted into the bearing 121, the inconvenience that the bearing 121 does not fit may occur. That is, there is a problem that the primer or the fluororesin paint contaminates the bearing portion 112 and deteriorates the fitting of the bearing 121.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to prevent sand blast powder from being mixed into a release layer, prevent contamination of a bearing portion, and release the mold. An object of the present invention is to provide an image forming apparatus having a fixing roller capable of improving both the performance and the fit of a bearing.

[0015]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a large-diameter paper-passing portion through which a recording paper on which a toner image is formed is passed, and both ends of the paper-passing portion. In an image forming apparatus having a fixing roller provided with a provided small-diameter bearing portion, a mask insertion groove surrounding an outer periphery of the bearing portion is formed on both end surfaces of the paper passing portion. This is an image forming apparatus having a fixing roller.

With this configuration, when processing the fixing roller, the mask can be fitted into the mask insertion groove.
Sandblast powder can be prevented from being mixed into the fluororesin surface, the fluororesin surface has a good releasability, and the bearing can be free from contamination by sandblast powder, primer and fluororesin powder.

According to a second aspect of the present invention, in the image forming apparatus having the fixing roller according to the first aspect, a cylindrical mask for protecting a bearing portion is inserted into the mask insertion groove when the fixing roller is manufactured. It is characterized by being a groove.

In this configuration, since the cylindrical groove can be fitted into the mask insertion groove on the end face of the paper passing portion, the positioning at the time of mounting the mask is easy.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a fixing roller provided in the image forming apparatus of the present invention, wherein FIG.
(B) is a front view. 2A and 2B are diagrams showing a state in which a mask is mounted on the fixing roller of FIG.
(B) is after mounting.

As shown in FIG. 1, a fixing roller 10 provided in the image forming apparatus of the present invention has a large-diameter paper passing portion 11 for passing a recording paper on which a toner image is formed, and both ends of the paper passing portion 11. And a small-diameter bearing portion 12 provided in the paper passing portion 11.
An annular groove 11b for inserting a mask, which surrounds the outer periphery of the bearing portion 12, is formed on both end surfaces 11b. Reference numeral 12a is a cut portion.

As shown in FIGS. 1 and 2, the fixing roller 10
Of the paper passing portion 11 having a depth of 0.1 to 1 in the circumferential direction.
A groove 11a having a thickness of 0.1 mm and a width of 0.1 to 1 mm is provided. Further, the mask 14 at the time of processing the fixing roller is fitted into the groove 11 a provided on the end face of the fixing roller 10 at the paper passing portion.

That is, a groove 1 having a depth of 0.1 to 1 mm and a width of 0.1 to 1 mm in the circumferential direction on both end surfaces of the paper passing portion of the fixing roller 10.
1a, and as shown in FIG.
As shown in FIG. 2B, the grooves 11a formed on both end surfaces 11b of the paper passing portion 11 of the fixing roller 10 are aligned with the mask 14 corresponding to the grooves 11a provided at the time of the processing. Fit in.

If the width of the groove 11a is less than 0.1 mm, it is difficult to fit the mask 14, and if the depth of the groove 11a is 0.1 mm or less, a gap is formed, and sandblast powder, primer, and fluorine resin paint enter. Will be. Groove 11
If the width of “a” exceeds 3 mm, the rigidity of the fixing roller 10 decreases, and the fixing roller 10 is broken by a load during use. Similarly, if the depth of the groove 11a exceeds 1.0 mm, the rigidity of the fixing roller 10 becomes weak.

FIG. 3 is a diagram showing the operation during the painting process.
(A) is during painting and (B) is after painting. FIG. 2 described above
In the state shown in FIG. 3B, a sandblasting process is performed, and FIG.
(A) As shown in FIG.
5 is spray-coated, and a fluororesin coating step is performed.

FIG. 4 is a side view of the fixing roller.
(A) is before painting and (B) is after painting. Before painting, the tip of the mask 14 is inserted into the circumferential groove 11a shown in FIG. After the coating, the fluorine resin coating F is applied to the outside of the groove 11a.

According to the above-described fixing roller 10, the end of the mask 14 enters the groove 11a provided on the end face of the fixing roller 10 when the fixing roller 10 is masked. There is no gap between
Sandblast powder, primer and fluororesin paint do not enter the bearing 12 of the fixing roller 10.

Further, conventionally, after the primer and the fluororesin have been applied, the paint adhered to the mask when the mask was detached or the extra paint adhered to the end face of the roller passing portion was sagged.
Although the bearing portion may be stained, in the present invention, it is possible to prevent excess paint from flowing into the groove 11 a provided on the end face 11 b of the paper passing portion 11, thereby preventing the bearing portion 12 from being soiled. Also, even if the paint slightly protrudes from the groove 11a,
Since the space is provided between the a and the bearing portion 12, the paint that has overflowed does not reach the bearing portion.

As described above, when the fixing roller 10 and the mask 14 of the present invention are used, since the sandblast powder, the primer and the fluororesin paint do not enter during the processing of the fixing roller 10, a release layer free of sandblast powder is obtained. And the releasability is improved. Further, since the bearing portion 12 is not contaminated, the fitting with the bearing is improved.

FIG. 5 is an explanatory diagram showing a main configuration of an image forming apparatus to which the present invention is applied. As shown in FIG. 5, the image forming apparatus includes a photosensitive drum 1 on which an electrostatic latent image is formed.
And a charging roller 2 that performs charging processing in contact with or close to the photosensitive drum 1, a developing roller 5 that attaches toner to an electrostatic latent image on the photosensitive drum 1, and a DC voltage is applied to the charging roller 2. , A transfer roller 6 for transferring the toner image on the photosensitive drum 1 to the recording paper P conveyed from the paper feeding unit, and a cleaning for removing and collecting residual toner on the surface of the photosensitive drum 1 The apparatus includes a device 7, a surface voltmeter 4 for measuring the surface potential of the photosensitive drum 1, a fixing roller 10, and a pressure roller 20. Note that reference numeral 3
Indicates exposure such as laser light or reflected light of a document.

An image forming operation in the image forming apparatus configured as described above will be described. First, the surface of the photosensitive drum 1 is uniformly charged to a high potential by supplying a DC voltage from the power supply 8 to the charging roller 2 contacting the photosensitive drum 1.

Immediately thereafter, when the surface of the photosensitive drum 1 is exposed 3, the potential of the exposed portion decreases. Since the exposure 3 has a light amount distribution corresponding to the image density, the exposure 3 forms a potential distribution with respect to the recorded image, that is, an electrostatic latent image on the surface of the photosensitive drum 1.

Next, when the portion on which the electrostatic latent image is formed passes through the developing roller 5, toner adheres according to the level of the potential, and a toner image is formed by visualizing the electrostatic latent image. You. Next, the recording paper P is transported at a predetermined timing to a portion where the toner image is formed, and overlaps the toner image. After the toner image is transferred onto the recording paper P by the transfer roller 10, the recording paper P is separated from the photosensitive drum 1.

Next, the separated recording paper P is conveyed through a conveyance path, is fixed by heat and pressure by the fixing roller 10 and the pressure roller 20, and is then discharged out of the apparatus. After the completion of the transfer, the surface of the photosensitive drum 1 is cleaned by the cleaning device 7, and the residual charge is erased by a residual charge erasing means (not shown) to prepare for the next image forming process.

(Examples) The present invention will be described in detail below with reference to examples. As a sample of the example, a fixing roller made of a drawn aluminum core having an outer diameter of φ30 mm of the bearing portion and an outer diameter of φ40 mm of the paper passing portion was used.

First, the entire length of the roller and the outer diameter of the bearing are cut. Because the bearing part is fitted with a resin drive gear,
Perform cutting. After that, a depth of 0.5
A groove with a width of 1.0 mm is cut. The outside diameter of the groove was φ37 mm. After cutting the outer diameter of the paper passing portion, sandblasting is performed. At this time, a mask having an outer diameter of φ37 mm that fits into grooves provided on both end surfaces of the paper passing portion was used.

The conditions for sandblasting were as follows: a blast material of # 180 was used, the nozzle distance was 100 mm, the sandblast pressure was 0.3 MPa, and the processing time was 40 seconds. After the sandblasting, the bearing portion and the inside of the mask were confirmed. However, no sandblasting powder entered, and the sandblasting powder could be removed by air blowing the paper passing portion after the sandblasting. Next, a wet primer coating was performed using a spray. Outer diameter φ37mm, also for primer coating,
A mask that fits into grooves provided on both end faces of the paper passing portion was used.

Although five consecutive coatings were performed, the extra primer adhered to the mask and the primer adhered to the end face of the paper passing portion flowed into the grooves provided at both end faces of the paper passing portion, and contaminated the bearing portion of the fixing roller. Did not. After the primer was applied, it was put into a furnace at 150 ° C. for 20 minutes to dry the primer. Next, the paper passing portion was subjected to electrostatic powder coating of fluororesin PFA (perfluoroalkoxy resin) powder. At this time, the mask shown in the present invention was used. As with the primer coating, there was no contamination of the bearing. After the coating of the fluororesin, it is put into a furnace at 380 ° C. for 40 minutes to form a fluororesin film on the paper passing portion. After firing, since the fluororesin surface has irregularities, polishing is performed to finish the fluororesin surface smooth.

In the fixing roller manufactured by using the present invention, no sandblast powder is mixed on the fluororesin surface, and the bearing portion is not contaminated by the sandblast powder, the primer and the fluororesin powder. On the other hand, in a fixing roller processed as in the related art without providing a groove on both end surfaces of the paper passing portion, sandblast was mixed into the fluororesin surface and Teflon powder adhered to the bearing portion.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the annular groove is described. However, other shapes can be used as long as the mask can be fitted to cover the bearing with the mask. That is, various modifications can be made without departing from the gist of the present invention.

[0040]

As described above, according to the present invention, since there is no sandblast powder mixed in the fluororesin surface, the fluororesin surface has a good releasability, and the sandblast powder, the primer, Since there is no contamination by the fluororesin powder, it is possible to provide an image forming apparatus having a fixing roller that can be inserted into the bearing without any problem.

When the mask insertion groove is an annular groove into which a cylindrical mask can be inserted, positioning when mounting the mask is easy, and the mask can be securely fitted in the groove.

[Brief description of the drawings]

FIG. 1 is a diagram showing a fixing roller provided in an image forming apparatus of the present invention, wherein FIG. 1A is a side view and FIG. 1B is a front view.

FIGS. 2A and 2B are views showing a state in which a mask is mounted on the fixing roller of FIG. 1, wherein FIG. 2A is before mounting and FIG.

3A and 3B are diagrams showing an operation during a painting process, wherein FIG. 3A is during painting and FIG. 3B is after painting.

FIG. 4 is a side view of a fixing roller.
(B) is after painting.

FIG. 5 is an explanatory diagram illustrating a main configuration of an image forming apparatus to which the present invention is applied.

6A and 6B are diagrams illustrating a fixing device provided in the image forming apparatus, wherein FIG. 6A is a front view and FIG. 6B is a side view.

FIG. 7 is a diagram schematically illustrating a processing step of a fixing roller.

8A and 8B are diagrams showing a state in which a mask is mounted on a fixing roller of a conventional image forming apparatus, wherein FIG. 8A shows a state before mounting and FIG. 8B shows a state after mounting.

[Explanation of symbols]

 11 paper passing portion 11a groove 11b end face 12 bearing portion P recording paper

Claims (2)

[Claims] 1. An image forming apparatus comprising: a fixing roller having a large-diameter paper passage portion through which a recording paper on which a toner image is formed and a small-diameter bearing portion provided at both ends of the paper passage portion. An image forming apparatus having a fixing roller, wherein a mask insertion groove surrounding an outer periphery of the bearing portion is formed on both end surfaces of the paper passing portion. 2. The image forming apparatus having a fixing roller according to claim 1, wherein the mask insertion groove is a groove into which a cylindrical mask for protecting a bearing portion is inserted when the fixing roller is manufactured.