JPH0527637A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent the staining of copying paper with oil and the generation of an offset by constituting the above device in such a manner that the coated amt. of the oil can be specified regardless of copying modes. CONSTITUTION:The fixing device for passing the copying paper between two upper and lower fixing rollers 1 and 2 provided in a pair and fixing the paper under heating and pressurizing has an oil applying roller 3 for applying the oil to the fixing roller 1 on the toner surface side of the copying paper and an oil supplying roller 4 for supplying the oil to the oil applying roller 3. This device is provided with an oil applying roller driving motor 9 for rotationally driving the oil applying roller 3 separately and independently from the fixing roller 1 and an oil applying roller control means 10 for changing the rotating speed of the oil applying roller 3 by controlling the oil applying roller driving motor 9 according to the copying modes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device having an oil applying roller for applying oil to a fixing roller.

[0002]

2. Description of the Related Art A conventional fixing device is constructed, for example, as shown in FIG.

First, an upper heat roller 11 having a hollow cylindrical shape and having a heater 11a provided therein and a lower heat roller 12 having a hollow cylindrical shape and having a heater 12a provided therein face each other and are pressed against each other. Is provided.

An oil applying roller 13 is provided on the side of the upper heat roller 11 so as to face the outer circumferential surface of the upper heat roller 11 in the axial direction, and further contacts the oil applying roller 14 to supply oil. A roller 14 is provided.

The oil supply roller 14 is held in a state in which a part thereof is immersed in the oil 5 contained in the oil tray 6.

Further, the oil applying roller 13 is provided with a blade 17 for making the oil supplied by the oil supply roller 14 uniform on the surface of the roller 13.

In the above-mentioned conventional fixing device, the upper heat roller 11 is rotationally driven by the drive motor, and the lower heat roller 12 is driven by the rotation of the upper heat roller 11.

The oil applying roller 13 is held in a state of being separated from the upper heat roller 11 except during the copying operation, and is moved to a position where it comes into pressure contact with the upper heat roller 11 after the copying operation is started. It was rotated following the rotation of 11. The oil application roller 13
The oil supply roller 14 was driven and rotated by the rotation of.

[0009]

In the above-mentioned conventional fixing device, since the oil applying roller is rotated in accordance with the rotation of the upper heat roller, the single color copying mode and the full color copying mode or the full color photographic copying mode are used. In some cases, there is a time difference caused by the difference in the number of exposure scans in the time from the start of the rotation operation of the oil application roller to the actual fixing.

Therefore, the amount of oil applied to the fixing roller varies depending on the copy mode. When the amount of application is large, the copy paper is contaminated with oil, and when the amount of application is small, offset occurs.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and it has two upper and lower fixing rollers (1 and 2) arranged opposite to each other and a toner surface side of a copy sheet. In the fixing device including the oil applying roller (3) for applying oil (5) to the fixing roller (1) and the means (4, 6) for supplying oil to the oil applying roller (3), An oil application roller drive means (9) for rotationally driving the roller (3) independently of the fixing roller (1) and an oil application roller by controlling the oil application roller drive means (9) according to the copy mode. An oil application roller control means (10) for changing the number of rotations of (3) is provided.

[0012]

According to the fixing device as described above, the number of rotations of the oil applying roller can be changed according to the copy mode, so that the optimum number of rotations suitable for the copy mode can be obtained. It is possible to obtain a constant oil application amount regardless of the copy mode by eliminating the variation in the amount. Therefore, it is possible to prevent oil stains and offset on the copy paper.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fixing device according to the present invention. In the figure, an upper fixing roller (upper heat roller) 1 is formed in a hollow cylindrical shape, and a heater 1a such as a halogen lamp is provided inside. The upper heat roller 1 is connected to the upper heat roller drive motor 8 via gear trains 8a and 8b, and is rotationally driven by the drive motor 8.

Lower fixing roller (lower heat roller) 2
Is formed in a hollow cylindrical shape like the upper heat roller 1,
Similarly, a heater 2a such as a halogen lamp is provided inside. The lower heat roller 2 is provided in pressure contact with the upper heat roller 1, and is configured to rotate following the rotation of the upper heat roller 1.

The oil applying roller 3 for applying oil to the upper heat roller 1 has a cylindrical shape made of, for example, a material in which a felt material is wound around an aluminum tube having a diameter of about 20 mm. 1 is provided so as to face the outer peripheral surface in the axial direction.

The oil applying roller 3 comprises gear trains 9a, 9
It is rotationally driven independently of the upper heat roller 1 by the oil application roller drive motor 9 via b.

An oil supply roller 4 is provided in contact with the oil applying roller 3. A part of the oil supply roller 4 is held in a state of being immersed in the oil 5 contained in the oil tray 6.

The oil supply roller 4 is constructed to rotate following the rotation of the oil application roller 3.

The oil supply roller 4 is for supplying oil to the oil application roller 3, and is formed by winding a felt material or silicon rubber around an aluminum tube.

Further, the oil applying roller 3 is provided with a blade 7 for making the surface of the oil supplied by the oil supply roller 4 uniform.

The oil applying roller drive motor 9 is connected to the oil applying roller control means 10.

The oil applying roller control means 10 controls the oil applying roller driving means 9 in accordance with each of the copying modes of the single color copying mode, the full color copying mode and the full color photo copying mode to change the rotation speed of the oil applying roller 3. It is for.

Specifically, for example, in the full-color copying mode in which exposure scanning is performed three times, the rotation speed of the oil application roller 3 is 113 r. p. set to m. The amount of oil applied per copy sheet at this time is about 25 mg.

Next, in the full-color photocopying mode, the exposure scanning is performed 6 times, which is twice as much as that in the full-color copying mode. If this is done, the amount of oil applied will be as large as about 32 mg, and there is a risk of oil stains on the copy paper.

Therefore, in the full-color photocopying mode, the number of revolutions is lowered to obtain the same oil application amount as in the full-color copying mode. In this embodiment, the rotation number for this is 103 r.p.m. p. m.

Next, since the exposure scanning is performed only once in the monochromatic copying mode of only one color, when the oil applying roller 3 is rotated at the same number of rotations as in the full color copying mode, the amount of oil applied is reduced to about 19 g. Therefore, an offset may occur.

Therefore, in the single color copying mode, the number of rotations is increased so that the oil application amount is the same as in the full color copying mode. The number of rotations for that purpose is 12 in this embodiment.
5r. p. m.

The rotational speed control operation of the oil applying roller 3 by the oil applying roller control means 10 of the fixing device of the present invention will be described with reference to the flowchart of FIG. First, in step S1, it is determined whether or not copying has started. If copying has started, step S2
Proceed to.

In step S2, it is determined whether the set copy mode is the full-color photocopy mode. If it is the full-color photocopying mode, the process proceeds to step S5, and the rotation speed of the oil application roller 3 is 103 r.
p. The oil application roller drive motor 9 is set to m and is rotationally driven. The rotational force is transmitted to the oil applying roller 3 via the gear trains 9b and 9a so that the oil applying roller 3 is rotated by 103
r. p. It is rotated by m.

When it is determined in step S2 that the mode is not the full-color photocopying mode, the process proceeds to step S3, and it is determined whether the mode is the full-color copying mode. In the full-color copying mode, the rotation speed of the oil applying roller 3 is 113 r. p. The oil application roller drive motor 9 is set to m and is rotationally driven.
Therefore, the oil applying roller 3 is 113 r. p. It is rotated by m.

If it is determined in step S3 that the full-color copy mode is not set, the flow advances to step S4 to determine whether the single-color copy mode is set. In the case of the single color copying mode, the rotation speed of the oil applying roller 3 is 125 r. p. The oil application roller drive motor 9 is set to m and is rotationally driven. Therefore, the oil applying roller 3 is 125 r. p. It is rotated by m.

When the oil applying roller 3 is rotated in steps S5, S6, and S7, the oil supply roller 4 is rotated in response to the rotation, and the oil 5 in the oil tray 6 passes through the oil supply roller 4. And is supplied to the oil applying roller 3.

At this time, the number of rotations of the oil applying roller 3 is set to the optimum number of rotations for each mode according to each copying mode, so that the oil application amount becomes constant regardless of the copying mode.

As described above, the oil application roller 3 is rotated at the optimum number of rotations according to the copy mode, a certain amount of oil is applied to the upper heat roller 1, and fixing is performed without causing copy paper stains or offset. be able to.

The copying is performed as described above, and it is determined in step S8 whether the copying is completed. When it is determined that the copying is completed, the process proceeds to step S9, and the oil application roller drive motor 9 is stopped.

In the above-described embodiment, the number of rotations of the oil applying roller is set to 103 r.p.m. in the full-color photocopying mode, the full-color copying mode and the single-color copying mode, respectively. p. m, 11
3r. p. m, 125r. p. Although m is set, it is not limited to this and may be changed as necessary.

[0037]

According to the fixing device of the present invention, the number of rotations of the oil applying roller can be changed according to the copying mode, so that the variation in the oil applying amount can be eliminated and the constant oil applying amount can be obtained regardless of the mode. can do. Therefore, it is possible to prevent oil stains and offset on the copy paper.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a fixing device according to the present invention.

FIG. 2 is a flowchart showing a rotation control flow of the oil application roller according to the present invention.

FIG. 3 is a diagram showing a schematic configuration of a conventional fixing device.

[Explanation of symbols]

 1 Upper Fixing Roller 2 Lower Fixing Roller 3 Oil Applying Roller 4 Oil Supply Roller 6 Oil Tray 9 Oil Applying Roller Drive Means 10 Oil Applying Roller Control Means

Claims (1)

Claim: What is claimed is: 1. A pair of upper and lower fixing rollers provided opposite to each other, an oil applying roller for applying oil to the fixing roller on the toner surface side of the copy sheet, and a means for supplying oil to the oil applying roller. In the fixing device including the oil applying roller, the oil applying roller driving means for rotating the oil applying roller independently of the fixing roller, and the oil applying roller driving means for controlling the oil applying roller according to the copy mode are controlled. A fixing device comprising: an oil application roller control unit that can change the number of rotations;