JP2001154523A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of preventing an oil applying roller or a cleaning roller from being brought into press contact by pressurizing both ends to a fixing roller or a pressurizing roller, the deflection of the oil applying roller or the cleaning roller from becoming large, the applying amount of oil from becoming large by the increase of only the nip of an end part and the cleaning of a center part from becoming insufficient, uniformly applying or sufficiently cleaning the oil over the entire paper passing width and further preventing an outer shape from becoming large and the entire device from being enlarged. SOLUTION: This fixing device is provided with the fixing roller, the pressurizing roller and the oil applying roller or the cleaning roller abutted to one of the rollers and the oil applying roller or the cleaning roller is composed of the plural rollers divided in the axial direction of a roller shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in this type of fixing device,
2. Description of the Related Art A fixing roller and a pressure roller, and an oil applying roller or a cleaning roller that abuts on one of these rollers to apply or clean silicone oil are known. The oil application roller applies silicone oil as a release agent to prevent toner or paper powder from adhering to the fixing roller or the pressure roller, and the cleaning roller uses the fixing roller or the pressure roller. This is to clean and clean the collected matter such as excess toner, paper dust, oil, etc. attached to the surface.

In such a fixing device, if the oil application roller does not apply the oil uniformly over the entire width of the paper passage, toner, paper dust and the like are partially fixed to form an offset image on transfer paper, There is a problem that streaks are generated on the transfer paper due to excess oil, and that the cleaning roller cannot be uniformly cleaned.

In such a fixing device, the oil application roller and the cleaning roller are normally pressed at both ends by pressure to the fixing roller or the pressure roller. If it is large, there is a problem that only the nip at the end is increased and the applied amount is larger than the applied amount at the central portion. Is pressurized and pressed against the pressure roller. Therefore, if the bending of the cleaning roller is large, there is a problem that the nip at the central portion is reduced and a sufficient cleaning effect of the portion cannot be obtained.

[0005]

To solve such a problem, a fixing device as disclosed in Japanese Patent Application Laid-Open No. H11-242402 has been proposed. In this fixing device, the pressure roller has a continuous shape, and a cleaning member having an outer shape matching the shape is brought into contact with the pressure roller for cleaning.

In this fixing device, since the pressure roller and the cleaning member have irregular shapes, it is difficult to process the pressure roller and the cleaning member, and the pressure of the fixing roller or the pressure roller must be changed depending on the type of paper. In some cases, when the deformation of the fixing roller or the pressure roller changes and the shapes of the pressure roller and the cleaning member change, it is difficult to cope with the change.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems of the conventional fixing device, and to press the oil application roller or the cleaning roller with both ends pressed against the fixing roller or the pressure roller. Without increasing the deflection of the oil application roller or cleaning roller, without increasing the nip at the end and increasing the amount of oil applied, or without insufficient cleaning at the center. An object of the present invention is to provide a fixing device which can apply oil uniformly over the entire width of the paper passing or can sufficiently clean it, does not increase the outer shape, and does not make the entire apparatus large.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a fixing device including a fixing roller, a pressure roller, and an oil application roller which contacts one of these rollers. The invention according to claim 1 is characterized in that the oil application roller includes a plurality of oil application rollers divided in the axial direction of the roller shaft.

The invention according to a second aspect is characterized in that the cleaning roller comprises a plurality of cleaning rollers divided in the axial direction of the roller shaft.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIGS. 1 and 2, 1 is a fixing roller, 2 is a pressure roller,
Reference numeral 3 'denotes an oil application roller, and the cleaning roller has the same structure as the oil application roller 3 except that the cleaning roller has no heater 4.
Since the configuration is the same as that described above, the description thereof will not be repeated with the description of the application rollers 3 and 3 '. The oil application rollers 3 and 3 ′ include a plurality of (three in this embodiment) rollers divided in the axial direction of the roller shafts of the fixing roller 1 and the pressure roller 2. Reference numeral 4 denotes a heater provided in the fixing roller 1, reference numeral 11 denotes transfer paper, and reference numeral 12 denotes a toner image.

The outer two oil application rollers 3
Are supported by support shafts 5, 6 arranged in the same axial direction, and an intermediate oil application roller 3 'is
Or, in the circumferential direction of the pressure roller 2, the other support shafts 5,
6 is supported by a support shaft 7 arranged in a staggered manner at a position different from that of the support shaft 6. The support shafts 5, 6, and 7 are supported by a bearing 9 provided on a device main body (not shown) by pressing with a spring 8.

In the above-described configuration, the oil application rollers 3 and 3 ′, which start operating and come into contact with the fixing roller 1 heated by the heater 4, rise in temperature.
The viscosity of the oil impregnated in the oil application rollers 3 and 3 ′ decreases and adheres to the fixing roller 1. As the fixing roller 1 rotates, the oil application rollers 3 and 3 ′ also rotate, and oil is applied to the entire circumference of the fixing roller 1 or the pressure roller 2, and the oil is applied to the fixing roller 1 or the pressure roller 2 for unfixed toner or the like. In the case of a cleaning roller, the fixing roller 1 or the pressure roller 2 is cleaned.

In this case, the bending of each of the three oil application rollers 3, 3 'is 1/27 of that of one oil application roller having the same cross section and three times as long, and the pressing force per unit length is reduced. If they are kept the same, the ratio becomes 1/81, the deviation of the oil application nip becomes extremely small, and the oil distribution of the fixing roller 1 can be made uniform.

Oil application rollers 3, 3 'divided into three parts
To achieve the same oil distribution difference with a single oil application roller, the outer diameter must be 2.9 for an outer diameter of 20 mm and a wall pressure of 1 mm.
To maintain the same pressure per unit length,
Need to double.

In this embodiment, the end faces in the longitudinal direction of the oil impregnated portions of the oil applying rollers 3 and 3 'are made to coincide with each other. By using the wraparound, the end faces may be spaced at a fixed interval, or may be overlapped on the contrary. When the intervals are widened, it is not necessary to arrange the oil applying rollers 3, 3 'in a staggered manner, and they can be arranged on the same axis. Further, a plurality of oil application layers may be arranged in series on the same roller in the axial direction, and a portion without the oil application layer may be pressurized. In this embodiment, since the intermediate oil application roller 3 'is arranged on the downstream side in the transport direction of the transfer paper, the rear side is a wide device installed on the wall surface side, and misfeed paper processing can be performed from the lateral direction. This is suitable for a fixing device that has high performance and wants to secure openings at both ends of the fixing roller 1.

In this embodiment, the oil application roller 3
Is divided into three, but may be divided into two or more. As described above, the present invention can be applied to a cleaning roller instead of an oil application roller.

[0017]

According to the present invention, as described above, the oil application roller or the cleaning roller which comes into contact with the fixing roller or the pressure roller comprises a plurality of rollers divided in the axial direction of the roller shaft. Since the length in the direction is shortened, the amount of deflection can be reduced, and the outer diameter of the oil application roller or the cleaning roller can be reduced, and as a result, without increasing the size of the entire apparatus,
There is an effect that uniform oil application or cleaning can be realized under a uniform nip distribution.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a side view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3, 3 'Oil application roller 4 Heater 5 Support shaft 6 Support shaft 7 Support shaft 8 Spring 9 Bearing 11 Transfer paper 12 Toner image

Claims (2)

[Claims] 1. A fixing device comprising: a fixing roller, a pressure roller, and an oil application roller abutting on one of these rollers, wherein the oil application roller has a plurality of oil application parts divided in an axial direction of a roller shaft. A fixing device comprising a roller. 2. A fixing device comprising a fixing roller, a pressure roller, and a cleaning roller abutting on one of these rollers, wherein the cleaning roller comprises a plurality of cleaning rollers divided in an axial direction of a roller shaft. A fixing device characterized by the above-mentioned.