JPH0594109A - Fixing device - Google Patents

Abstract

PURPOSE:To provide a fixing device capable of preventing the excessive supply of oil for separating a paper at an initial using stage and the shortage of the oil supply at the latter using stage. CONSTITUTION:The fixing device D1 is provided with a heat roller 1 and a pressure roller 2 arranged under the heat roller 1 so that it may be press- contacted with the roller 1 by a pressure spring 3. A 1st oil applying roller 8 which can be rotated in a press-contact state with the heat roller 1 is installed on the left upper part of the heat roller 1. The silicone oil for separating the copying paper is always supplied to the heat roller 1 by the 1st oil applying roller 8. A 2nd oil applying roller 9 is installed on the right side of the 1st oil applying roller 8 at a fixed interval with reference to the heat roller 1. The 2nd oil applying roller 9 can be moved upward and downward, and when the total number of copied sheets becomes a prescribed number of sheets, for example it becomes 4000 sheets, the roller 9 is press-contacted with the heat roller 1 for the first time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device, and more particularly to a fixing device incorporated in a fixing portion of an image forming apparatus such as a copying machine or a printer to fix a toner image transferred onto an image forming sheet.

[0002]

2. Description of the Related Art Conventionally, as a fixing device incorporated in an image forming apparatus, a rotatably arranged heat roller for fusing a toner image transferred onto the surface of an image forming sheet and drying the sheet, and a heat roller 2. Description of the Related Art There is known one provided with a pressure roller which is arranged in pressure contact with a roller and which rotates together with a heat roller to convey a paper while drying the paper.

In such a fixing device, in order to easily separate the paper from the heat roller and the pressure roller, the surface of the heat roller which is in contact with one of the both surfaces of the paper on which the toner image is formed is usually used. The paper separation oil is supplied to the. Here, 1 of the method of supplying the same oil
As an example, an oil application roller having oil sealed inside or held on the surface is rotatably pressed against a heat roller, and the oil is gradually exuded from the oil application roller to apply the oil to the heat roller. The method is known.

[0004]

However, according to the fixing device having the oil applying roller as described above, the amount of oil seeping out from the oil applying roller gradually decreases after a certain period of use. It becomes impossible to supply an appropriate amount of oil to the heat roller. Therefore, if it is attempted to extend the usable time by increasing the amount of oil that is enclosed or retained on the surface, there is a problem that the oil is excessively supplied to the pressure roller at the initial stage of use. The present invention has been made in view of the above circumstances, and an object thereof is to prevent excessive supply of oil for paper separation at the initial stage of use and insufficient supply of oil at the latter stage of use, and reduce the number of oil supply operations. It is to provide a fixing device capable of performing.

[0005]

According to the present invention, there is provided a heat roller which is rotatably arranged and which fuses a toner image transferred onto the surface of an image forming sheet and dries the sheet, and a heat roller which is pressed against the heat roller. And a pressure roller that rotates together with the heat roller and conveys the paper while drying it. Further, the heat roller and the pressure roller are rotatably arranged so that the paper can be easily separated from the heat roller and the pressure roller. To this end, a first oil applying roller for supplying the paper separating oil to the surface of the heat roller in an applied state, and a rotatably arranged predetermined distance from the heat roller in the vicinity of the first oil applying roller are provided. The fixing device is provided with a first oil applying roller that is sometimes brought into pressure contact with the heat roller and a second oil applying roller that supplies the oil to the surface of the heat roller.

That is, the fixing device of the present invention is provided with two peculiar oil applying rollers, one of the oil applying rollers is always kept in pressure contact with the heat roller, and the other oil applying roller is set at a predetermined time, that is, in advance. The main point is that the heat roller is pressed into contact with the heat roller only when the number of images to be formed is reached.

[0007]

As the two oil application rollers, ones in which the paper separating oil is enclosed or held on the surface are used. The oil constantly exudes from one of the oil application rollers, and the oil is applied and supplied to the surface of the heat roller. The other oil application roller is separated from the heat roller in the initial stage of use, and is pressed against the heat roller at a predetermined time to gradually exude oil, and the oil is applied to the surface of the heat roller together with the one oil application roller. Supply.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to two embodiments shown in the drawings. The present invention is not limited to these.

Embodiment 1 In FIG. 1, a fixing device D ₁ incorporated in a copying machine is
A heat roller 1 for fusing the toner image transferred onto the surface of the copy paper (not shown) and drying the copy paper, and a heat roller 1 disposed below the heat roller 1 with a pressure spring 3 in pressure contact therewith. 1 and a pressure roller 2 which is rotated together with 1 to convey the copy paper in the direction of the arrow in the drawing while drying the copy paper. And
In order to guide the copy sheet, a front guide 4 is provided on the upstream side in the transport direction and a rear guide 5 is provided on the downstream side. A discharge roller 6 is provided on the rear guide 5, and the discharge roller 6 is pressed against a discharge roller 7 provided above the discharge roller 6.

The fixing device D ₁ further includes a first oil applying roller 8 arranged on the upper left side of the heat roller 1 so as to be rotatable in pressure contact with the heat roller 1. The first oil application roller 8 supplies the copy paper separating silicon oil to the surface of the heat roller 1 in an applied state in order to easily separate the copy paper from the heat roller 1 and the pressure roller 2.

The first oil applying roller 8 is for a long and slender cylindrical roller body, a roller sheet wound five times around the peripheral wall surface of the roller body, and a roller wound once on the roller sheet. It is equipped with felt. Then, 116 g of silicone oil having a kinematic viscosity of 5000 cSt is sealed inside the roller body. Further, a total of 15 oil exudation holes having a diameter of 1 mm are uniformly provided on the peripheral wall surface of the roller body so that the silicone oil exudes evenly from the peripheral wall surface. On the outermost felt surface of the first oil applying roller 8, 8 g of the same silicone oil that is enclosed in the roller body,
It is evenly applied. Silicon oil is constantly supplied to the heat roller 1 by such a first oil application roller 8.

The fixing device D ₁ further includes, on the right side of the first oil applying roller 8, a second oil applying roller 9 which is rotatably arranged at a constant interval from the heat roller 1. The second oil applying roller 9 has the same structure as the first oil applying roller 8, 58 g of the same silicone oil as the above is sealed therein, and there are a total of eight oil exudation holes having a diameter of 1 mm. Are provided uniformly,
On the outermost felt surface, 8 g of the same silicone oil that was sealed in the roller body was uniformly applied.

The second oil applying roller 9 is movable up and down, and is pressed against the heat roller 1 only when the total number of copies reaches 4000. That is, as shown in FIG. 2, the second oil applying roller 9 is urged toward the heat roller 1 by the compression coil springs 10 attached to the ends 9a and 9b of the roller shaft. The heat roller 1 is arranged at a constant interval via the projecting operating portion 11a of the solenoid 11 arranged at the one (right) end 9b.

The use of the fixing device D ₁ started in the state as shown in FIG. 2, the number of copies increased, and the total number of copies reached 4000.
When the number of sheets is reached, the solenoid 11 is actuated and the actuating portion 1
1a retracts. Then, the second oil applying roller 9 is pressed against the heat roller 1 by the compression coil springs 10. As a result, silicon oil is supplied to the heat roller 1 from both the first oil application roller 8 and the second oil application roller 9.

A total of 10,000 copies were made by the fixing device D ₁ thus constructed. When the relationship between the total number of copies (sheets) and the supply amount of silicon oil per copy sheet (mg / sheet) to the heat roller 1 at that time was examined, the results shown in FIG. 4 were obtained. .. In FIG.
When the oil supply amount is in the range of 5 to 10 mg / sheet, good separation of copy paper is performed.

In FIG. 4, the total number of copies is 4000.
At the time of sheet number, the oil supply amount to the heat roller 1 is increased from 5 mg / sheet to 10 mg / sheet because the second oil applying roller 9 is pressed against the heat roller 1. This is because the silicone oil is supplied from both the application roller 8 and the second oil application roller 9. The total number of copies is 4000-10000.
It can be seen that a good oil supply was made during the one sheet.

In this fixing device D ₁ , as compared with the conventional fixing device, the excessive supply of the paper separating oil at the initial stage of use and the latter period of use (the total number of copies is 4000 to 100).
It is possible to prevent shortage of oil supply in (00 sheets) and reduce the number of oil supply operations.

Embodiment 2 In FIG. 5, the fixing device D ₂ of the copying machine is provided with a second oil application roller 9. The second oil applying roller 9 is arranged at a constant distance from the heat roller 1 by the two spacers 12 and 12 arranged at the ends 9a and 9b of the roller shaft, respectively. The other structure of the fixing device D ₂ is the same as that of the first embodiment.

When the use of the fixing device D ₂ started and the number of copies increased and the total number of copies reached 4000,
The two spacers 12 and 12 are removed by the user,
It was pressed against the second oil application roller 9. Then, a total of 10,000 copies were made. The result at that time was the same as that of FIG.

In this fixing device D ₂ , as compared with the conventional fixing device, the excessive supply of the paper separating oil in the initial stage of use and the latter period of use (the total number of copies is 4000 to 100).
It is possible to prevent shortage of oil supply in (00 sheets) and reduce the number of oil supply operations.

[0021]

Since the fixing device according to the present invention is configured as described above, it is possible to prevent an excessive supply of the paper separating oil in the initial stage of use and an insufficient supply of the oil in the latter stage of use. The number of replenishment operations can be reduced.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a fixing device according to a first embodiment of the present invention.

FIG. 2 is a structural explanatory view showing a state of a second oil applying roller in an initial stage of use of the fixing device.

FIG. 3 is a structural explanatory view showing a state of a second oil application roller in a latter stage of use of the fixing device.

FIG. 4 shows a total of 10,000 copies by the fixing device.
The figure which shows the transition of the oil supply amount when performing one sheet.

FIG. 5 is a structural explanatory view showing a state of a second oil applying roller in an initial stage of use of the fixing device according to the second embodiment of the present invention.

FIG. 6 is a structural explanatory view showing a state of a second oil applying roller in the latter stage of use of the fixing device.

[Explanation of symbols]

 1 Heat Roller 2 Pressure Roller 8 First Oil Applying Roller 9 Second Oil Applying Roller 10 Compression Coil Spring 11 Solenoid 12 Spacer

Claims (1)

[Claims] 1. A heat roller that is rotatably arranged to fuse a toner image transferred onto the surface of an image forming paper and dry the paper; and a heat roller that is arranged in pressure contact with the heat roller and rotates together with the heat roller. And a pressure roller that conveys the paper while drying it, and is rotatably arranged in pressure contact with the heat roller. A first oil applying roller that supplies the paper separating oil in an applied state, and is rotatably arranged in the vicinity of the first oil applying roller at a certain distance from the heat roller and is pressed against the heat roller at a predetermined time. A fixing device comprising a first oil application roller and a second oil application roller that supplies the oil to the surface of the heat roller.