JP2003029560A - Thermal fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take measures to cope with the excessive supply of oil in the case of the temperature rise of an oil tank roller by stabilizing oil supply amount in a fixing device. SOLUTION: When the detected temperature of the oil tank roller by a temperature detection member is equal to or above specified temperature, the oil tank roller is separated from a heating roller through a void, and when it is equal to or under the specified temperature, the oil tank roller is brought into contact with the heating roller and rotated counterclockwise by frictional force between the rollers so as to coat the heating roller with the oil.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a fixing device having an oil applying device for applying oil to a heating roller of an electrophotographic apparatus using electrophotographic technology. [0002] The amount of oil bleeding is controlled by selecting the size and number of oil supply holes in an oil tank roller and the viscosity of the oil, thereby controlling the amount of oil applied to a heating roller. [0003] The heating roller fixes the toner image on the paper by heating and pressing the toner image on the paper. At this time, if there is no oil supply to the heating roller, the releasability of the heated and pressurized toner image from the heating roller is reduced, toner adheres to the heating roller, and the heating roller becomes dirty. It is necessary to supply oil stably, and as one means for this, an oil tank roller is known. The oil tank roller has a mechanism for holding and storing oil inside, has an oil supply hole inside the oil tank, and exudes oil from the supply hole and heats the roller via a brush wound around the tank outer periphery. And apply oil. Conventionally, an oil tank roller always contacts a heating roller and is supplied with heat from the heating roller.
As a result, the temperature of the oil tank roller rises with time, the viscosity of the oil stored inside decreases, and the amount of oil passing through the oil supply hole provided in the oil tank roller eventually exceeds a predetermined value. Oil is excessively supplied to the heating roller, which is always in contact with the brush through the wound brush, and excessive oil adheres to the printing paper, causing the paper to become stained with oil. When oil attached to the paper adheres to the paper, it becomes oily in the paper transport path system and becomes an obstacle to paper transport, causing paper jams.In machines with a mechanism that performs double-sided printing, paper with a large amount of oil Was printed again, and the image was disturbed due to adhesion to the photoreceptor. In the prior art, the amount of oil bleeding is adjusted by selecting the size and number of oil supply holes of the oil tank roller and the viscosity of the oil, and the amount of oil applied to the heating roller is controlled. If the oil supply during the rise is reduced, the oil supply under low temperature conditions, such as immediately after the machine is started, is reduced, and it is very difficult to balance the stable supply of oil. SUMMARY OF THE INVENTION The present invention stabilizes the amount of oil supply and takes measures against excessive supply of oil when the temperature of the oil tank roller rises. [0007] In order to solve the above problems, when the temperature of the oil tank roller reaches a certain temperature, the brush of the oil tank roller is held with a certain gap from the heating roller. When the temperature of the oil tank roller is reduced to a certain temperature or lower, the separated oil tank roller is brought into contact with a certain gap. The present invention will be described below with reference to the accompanying drawings. In FIG. 1, a heating roller 1 having a heat source
And a pressure roller 2 pressed against the heating roller 1. The heating roller 1 rotates clockwise, and the pressure roller 2 pressed against the heating roller 1 rotates counterclockwise to print between the pressed portions of the two rollers. The toner image 4 is fixed to the printing paper 3 by passing the paper 3 and heating and pressing the toner image 4. The oil tank roller 5 has a brush on its surface for supplying oil by contacting the heating roller 1, and the oil tank roller 5 is rotatably held by an oil tank roller holding portion 7 of a holding member 6. When the oil tank roller 5 comes into contact with the heating roller, it is rotated counterclockwise by frictional force. Further, a solenoid 9 is fixed to an operating point 8 on the opposite side of the oil tank roller holding portion 7, and the solenoid 9 moves downward, so that the oil tank roller holding portion 7 Tank roller 5
Are spaced apart from the heating roller 1 with a gap 11 therebetween. In FIG. 2, the oil tank roller 5 is fixed to an oil tank roller holding portion 7 of a holding member 6 as in FIG. A solenoid 9 is fixed to an operating point 8 on the opposite side of the oil tank roller holding section 7, and the solenoid 9 is moved upward, so that the oil tank roller holding section 7 and the oil tank around the support point 10 of the holding member 6. Roller 5
Is in contact with the heating roller 1, rotates counterclockwise by frictional force, and applies oil to the heating roller 1. The temperature detecting member 12 is arranged so as to be in contact with the oil tank roller 5. The oil tank roller 5 is connected to the temperature detecting member 12.
If the detected temperature is equal to or higher than a predetermined temperature, the oil tank roller 5 is moved from the heating roller to a gap 11 as shown in FIG.
And release the oil tank roller 5 so that the temperature detecting member 1
If the detected temperature is lower than a predetermined temperature, the oil tank roller 5 is brought into contact with the heating roller 1 and rotates counterclockwise by the frictional force to apply oil to the heating roller 1. The predetermined temperature at which the oil tank roller is in contact with the heating roller is equal to the predetermined temperature at which the oil tank roller is separated from the heating roller, but may be different with hysteresis in order to perform advanced control. As described above, according to the present invention, the excessive supply of oil is eliminated, and the oil supply amount is optimized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing one embodiment of a heat fixing device of the present invention. FIG. 2 is a longitudinal sectional view showing one state of an embodiment of the heat fixing device of the present invention. [Description of Signs] 1 ... Heating roller, 2 ... Pressure roller, 3 ... Printing paper, 4 ...
Toner image, 5: oil tank roller, 6: holding member,
7: oil tank roller holding portion, 8: operating point, 9: solenoid, 10: support point, 11: gap, 12: temperature detecting member.

Continuation of front page    F-term (reference) 2H033 AA32 AA39 BA32 BA43 BA44                       BA46 CA07 CA26                 4F040 AA05 AA12 AB08 AC01 BA02                       BA07 CA12 DA07 DA14 DB02

Claims (1)

Claims: 1. A heating roller, a pressure roller, an oil tank roller that is in contact with the heating roller and holds oil therein, an oil supply hole inside the oil tank, and oil from the oil supply hole. A fixing member for an electrophotographic apparatus, comprising: an oil application device for applying oil while contacting a heating roller via a brush wound around the tank and extruding the oil tank roller; and a detecting member for detecting a temperature of the oil tank roller. When the temperature to be detected is equal to or higher than a predetermined temperature, the brush of the oil tank roller is separated from the heating roller by a certain gap, and when the temperature detected by the detecting member becomes equal to or lower than the predetermined temperature, the gap is reduced. A fixing device for contacting an oil tank roller separated from the fixing device.