JPH05150680A - Oil applying and recovering device - Google Patents

Abstract

(57) [Abstract] [Purpose] Oil is supplied to the oil application member of the fixing roller, excess oil is collected in the oil tank, and reused to prevent oil clogging. [Structure] Oil application / recovery for a heat fixing device, in which oil is supplied from an oil storage section to an oil application member of a fixing section through a feeding means, and excess oil is recovered and returned to the oil storage section for reuse. In the apparatus, an oil supply sensor is provided in the oil supply area for the oil application member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil applying / collecting device for a fixing device which is applied to an image forming apparatus such as a laser printer, a copying machine and a facsimile.

[0002]

2. Description of the Related Art For example, in electrophotography, an electrostatic latent image is formed on a photoconductor having a photoconductive substance, the latent image is developed by charged fine powder particles, and then the image is formed on a support. After transferring, the fine particles are finally fixed to the support by heating to obtain a copy. As a fixing method having a fixing roller, when a dry powder developer is used, a heat roller fixing device is widely used which passes a support having a visible image between a heated roller and a pressure roller. .. In this type of fixing device, fine powder particles (toner) are easily fused to the heating roller (this is called an offset phenomenon), the quality of the copy image is deteriorated, or the support is wound around the heating roller. there were. To prevent this offset phenomenon, a material with a small surface free energy, such as silicone rubber or Teflon (trade name), is used as the material of the heating roller surface that comes into contact with the visible image. The method of forming the silicone oil film of (1) using an offset prevention liquid coating device is used.

FIG. 4 is a cross-sectional view of a conventionally known fixing device equipped with an offset prevention coating device. FIG. 5 shows the offset prevention coating device in which oil is supplied from an oil tank 8 by a supply tube 6 to the coating felt 5. The oil is being supplied to the oil sump 12 in contact with.

A mechanism for supplying oil to the fixing portion will be described below.

In FIG. 5, the gear of the fixing knob shaft 1 on the front side of the fixing unit and the cam gear 2 mesh with each other.
The roller part of the oil pump is in contact with. The fixing drive gear rotates, the roller portion of the oil pump also moves along the cam, and the oil pump 3 is pressed to replenish the oil sump 12 with oil.

The details of the oil pump 3 are shown in FIG.
That is, FIG. 6 shows a valve provided in the supply tube 6,
There are valves at both ends to prevent backflow of oil.

With such a replenishing mechanism, oil is supplied,
Oil is collected by the metering blade 4 of FIG. 4, returned to the oil tank 8 and reused.

As such a mechanism for stabilizing and controlling the amount of silicone oil supplied to the surface of the heating roller, for example, in JP-A-54-12846, an oil holding container and an oil supply container are provided. A structure including means for circulating oil is disclosed.

[0009]

However, in such a conventional mechanism, when collecting the used oil, the paper dust of the transfer paper, the offset toner, etc. are returned to the oil tank together with the collected oil. There is. If it is continuously used in such a form, the transfer paper components such as clay and paper dust will be deposited on the bottom of the oil tank. In the conventional mechanism, since the oil suction tube is in contact with the bottom of the tank, there is a problem in that the precipitate is sucked up, the valve of FIG. 5 is clogged, suction failure occurs, and oil cannot be supplied. If oil is not applied to the fixing device that requires the oil applying device, as described above,
Offsets and jams occur.

In view of the above problems of the conventional oil applying / recovering device, the present invention supplies the oil to the oil applying member of the fixing roller, collects the excess oil in the oil tank, and reuses the device. The problem is to prevent oil clogging.

[0011]

The present invention solves this problem by
In an oil application / recovery device for a thermal fixing device, which supplies oil from the oil storage part to the oil application member of the fixing part via the feeding means, recovers excess oil, and returns the oil to the oil storage part for reuse. The problem is solved by providing an oil supply sensor in the oil supply area to the oil application member.

The feeding means comprises an oil pump and an oil suction tube, and the suction end of the tube is
Suitably, it is configured to be remote from the bottom of the oil reservoir.

It is more preferable that an oil end sensor is provided in the oil storage section and the height of the sensor section and the suction end of the oil suction tube are substantially at the same position.

It is also preferable to provide means for stopping the flow of foreign matter during the recovery of the excess oil in the oil storage section.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments based on the drawings.

In FIG. 1, the oil is directly conveyed and supplied from the oil tank 8 to the coating felt 5 via the tube 6. An oil supply sensor 7 is provided on the outlet side of the tube 6. The type of sensor may be a vibration type sensor or a pressure sensor. When the oil runs out, the signal from this sensor informs the operation section that the oil supply is insufficient and stops the image formation.

FIG. 2 is a schematic view of the oil tank. The oil tank 8 is provided with an oil suction tube 9 and an oil end sensor 10. Oil recovery port 1
Excess oil returns to 1. In the conventional case, the oil suction tube was in contact with the oil bottom portion, so that suction failure occurred. However, in this embodiment, the end portion of the oil suction tube is separated from the tank bottom portion. The distance is preferably about 5 mm or more. Further, it is preferable that the end portion of the oil end sensor 10 has substantially the same height as the sensor portion of the oil end sensor 10.

FIG. 3 schematically shows the oil sump 12.
The oil sump 12 is, for example, an integrally molded product of resin, and has a function of returning excess oil to the oil tank. By providing the groove or protrusion 11 at the bottom of the oil sump 12, foreign matter such as paper dust collected together with the oil from the metering blade 4 is blocked. As a means having a similar function, the bottom surface may be roughened. It is sufficient that the surface roughness Rz is 20 to 30 μm.

[0019]

In the oil applying / recovering apparatus according to the first aspect of the present invention, by providing the oil supply sensor in the oil supply region to the oil applying member, it is possible to surely detect the shortage of the oil supply. Since only the end sensor is provided, it is possible to prevent offset or the like due to poor oil supply when suction failure occurs.

In the oil applying / recovering device of the second aspect, since the suction end of the oil suction tube is configured to be separated from the bottom of the oil storage part,
It becomes difficult for foreign substances such as paper dust to be sucked up, and the valve clogging that has conventionally occurred in about 100K sheets does not occur even in 500K sheets.

In the oil applying / recovering device of the third aspect, since the oil end sensor is provided in the oil storage part and the height of the sensor part and the suction end of the oil suction tube are substantially at the same position, It is possible to reliably interlock the oil end sensor while preventing suction of foreign matter.

In the oil applying / recovering apparatus of the fourth aspect, since means for stopping the flow of foreign matter is provided during the recovery of the surplus oil to the oil storage section, dust of paper powder or toner may enter the oil storage section. It is possible to prevent the oil supply failure.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an oil application / collection device and a fixing roller according to the present invention.

FIG. 2 is a schematic view of an oil tank.

FIG. 3 is a schematic view of an oil sump.

FIG. 4 is a cross-sectional view of a conventionally known fixing device equipped with an offset prevention coating device.

5 is a diagram showing an oil supply state in the offset prevention coating apparatus of FIG.

FIG. 6 is a partial detailed view of an oil pump.

[Explanation of symbols]

 4 Metering blade 5 Coating felt 6 Tube 7 Oil supply sensor 8 Oil tank 12 Oil sump

Claims (4)

[Claims] 1. An oil application device for a heat fixing device, wherein oil is supplied from an oil storage part to an oil application member of a fixing part via a feeding means, and excess oil is collected and returned to the oil storage part for reuse. In the recovery device, an oil supply sensor is provided in the oil supply region to the oil application member. 2. The apparatus according to claim 1, wherein the feeding means is composed of an oil pump and an oil suction tube, and the suction end of the tube is separated from the bottom of the oil storage section. . 3. The oil end sensor is provided in the oil storage unit, and the height of the sensor unit and the suction end of the oil suction tube are set to substantially the same position height. apparatus. 4. The apparatus according to claim 1, further comprising means for stopping the flow of foreign matter during the recovery of the excess oil in the oil storage section.