JPH05113736A - Fixing device - Google Patents

Abstract

PURPOSE:To keep the cleaning effect of a cleaning means desirable without using a member such as a scraper. CONSTITUTION:A cleaning roller 6 is rotatory-driven in such a way as to be reversed in the rotating direction at its contact part with a fixing roller 1. In an application felt 4, one end is dipped in oil stored in an oil pan 7, its intermediate part 4b is brought into contact with the fixing roller 1, and its tip part, the other end, is brought into contact with the cleaning roller 6 in the counter direction. A toner stuck to the cleaning roller 6 is thereby cleaned without using a scraper or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller heated by heating means, a pressure roller pressed against the fixing roller, and a coating felt for coating an offset preventing liquid on the surface of the fixing roller. The present invention relates to a fixing device having a cleaning unit that cleans the surface of a fixing roller.

[0002]

2. Description of the Related Art Fixing devices of the above type are well known and are used in copying machines, printers, facsimiles and the like. In this type of fixing device, when the transfer paper carrying the toner image is heated and pressure-fixed, a small amount of toner adheres to the fixing roller. The offset toner is cleaned with a coating felt or a blade, but when the amount of the offset toner is large, such as in a full-color copying machine, a large amount adheres to the coating felt and the life of the offset toner is shortened. Therefore, as shown in FIG. 6, cleaning means using the cleaning roller 21 is brought into contact with the fixing roller 20 to enhance the cleaning effect. Note that FIG.
Reference numeral 23 is a pressure roller, 24 is a coating felt, and 25 is a blade.

[0003]

However, in the fixing device provided with the cleaning roller 21, there is a problem that the toner adhering to the cleaning roller 21 must be scraped off by the scraper 22 or the like in order to maintain the cleaning function. Further, even if the cleaning roller 21 is brought into contact with the fixing roller 20, there is a problem that the offset toner slips between both rollers.

The present invention solves the above-mentioned conventional problems,
An object of the present invention is to provide a fixing device capable of maintaining the cleaning means in good cleaning effect without using a member such as a scraper.

[0005]

The structure of the present invention which achieves this object is as follows.

(1) The fixing roller heated by the heating means, the pressure roller pressed against the fixing roller, the coating felt for coating the surface of the fixing roller with the offset preventing liquid, and the surface of the fixing roller. In a fixing device having a cleaning unit for cleaning, the cleaning unit includes a cleaning roller which is in contact with the surface of the fixing roller and is rotationally driven in a direction opposite to the fixing roller, and the coating felt is brought into contact with the cleaning roller. A fixing device characterized by the above.

(2) The coating felt is characterized in that its tip is in contact with the cleaning roller in a counter direction and its tip edge is in contact with the axis of the cleaning roller in an inclined manner. ) The fixing device described in (1).

(3) The fixing roller according to the above (1) or (2), characterized in that the cleaning roller is provided with a spiral projection having a height of 1 mm or less on the peripheral surface over the entire width thereof. apparatus.

[0009]

According to the above construction (1), since the coating felt comes into contact with the cleaning roller which is rotationally driven in the opposite direction to the fixing roller, the cleaning effect of the cleaning roller is kept good without using a member such as a scraper. It can be done.

According to the above configuration (2), the tip of the coating felt is in the counter direction with respect to the cleaning roller,
Moreover, since the tip edge of the offset roller is inclinedly contacted with the axis of the cleaning roller, the offset toner can be discharged from the axis edge of the cleaning roller along the tip edge of the coating felt.

According to the above configuration (3), since the cleaning roller is provided with the spiral protrusion having a height of 1 mm or less on the peripheral surface over the entire width thereof, the offset toner is applied to the shaft end of the cleaning roller by the protrusion. It can be guided and discharged.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic explanatory view of a fixing device according to the present invention. In FIG. 1, reference numeral 1 is a fixing roller, 2 is a pressure roller pressed against the fixing roller 1, the fixing roller 1 is rotationally driven in the clockwise direction, and a heater 3 as a heating means is arranged therein. .. The fixing device includes a coating felt 4 for coating an offset preventing liquid such as silicone oil on the surface of the fixing roller 1, a blade 5 for evenly distributing the coated oil, and a coating felt 4 in the rotation direction of the fixing roller 1. A cleaning roller 6 as a cleaning unit is provided on the upstream side, and the coating felt 4, the blade 5, and the cleaning roller 6 are arranged so as to be in contact with the surface of the fixing roller 1.

The cleaning roller 6 is rotationally driven in the reciprocal direction at the contact portion of the fixing roller 1, that is, in the clockwise direction so that the rotation direction is opposite. Further, one end of the coating felt 4 is immersed in the oil stored in the oil pan 7, the intermediate portion 4b is brought into contact with the fixing roller 1, and the other end portion 4a is brought into contact with the cleaning roller 6 in the counter direction. There is.

In the thus constructed fixing device, when the transfer paper 10 carrying the toner image T is nipped between the fixing roller 1 and the pressure roller 2, the toner image T is fixed on the transfer paper 10. At this time, the toner T offset on the fixing roller 1
2 adheres to the cleaning roller 6 as shown in FIG.
It is stopped by the tip 4 a of the coating felt 4.
Further, the toner slipped between the fixing roller 1 and the cleaning roller 6 is stopped by the intermediate portion 4b of the coating felt 4 which comes into contact with the fixing roller 1.

Thus, the offset toner attached to the cleaning roller 6 can be cleaned without using a scraper or the like, and the cleaning function of the cleaning roller 6 can be maintained.

In FIG. 3, the tip portion 4 of the coating felt 4 is shown.
a is in contact with the axis of the cleaning roller 6 with an inclination of an angle θ. By configuring like this,
The toner carried by the cleaning roller 6 is moved to the end portion side of the cleaning roller 6 along the tip end portion 4a of the coating felt 4, and is discharged from the shaft end thereof.

In this way, toner is prevented from accumulating at the tip 4a of the coating felt 4, and the life of the coating felt 4 can be extended.

FIG. 4 is a perspective view of a cleaning roller 6 showing another embodiment of the present invention. In this embodiment, a spiral projection 8 is formed on the circumferential surface over the entire width thereof. In this case, the surface of the cleaning roller 6 is made of a heat-resistant material such as a fluororesin coating or a silicone rubber layer. The protrusion 8 is made of silicone rubber and is a separate body when the cleaning roller 6 is coated with a fluororesin, and a separate body when the cleaning roller 6 is a silicone rubber layer.
It is provided integrally.

The protrusion 8 smoothly guides the toner adhering to the cleaning roller 6 to the end portion by the rotation thereof, and discharges the toner from the end portion. It should be noted that if the height of the protrusion 8 is set so as not to exceed 1 mm, it is advantageous in toner conveyance.

FIG. 5 shows a modification of FIG. 4, in which a spiral groove 9 is formed on the surface of the cleaning roller 6 instead of the protrusion 8. Also in this case, the toner attached to the cleaning roller 6 can be smoothly guided to the end portion by the rotation thereof along the groove 9.

[0021]

According to the first aspect of the present invention, the cleaning effect of the cleaning roller can be satisfactorily maintained without using a member such as a scraper, and it can be provided in a space-saving and inexpensive manner.

According to the second aspect, the offset toner can be discharged from the shaft end of the cleaning roller along the tip edge of the coating felt, and the toner is not accumulated on the coating felt, so that the life thereof is extended.

According to the third aspect, since the offset toner can be guided to the shaft end of the cleaning roller by the projection and discharged, the toner is not accumulated on the coating felt and the life thereof is extended.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a fixing device according to the present invention.

FIG. 2 is an enlarged explanatory diagram of a main part of FIG.

FIG. 3 is an explanatory diagram showing a relationship between a cleaning roller and a leading edge of a coating felt.

FIG. 4 is a perspective view showing another embodiment of the present invention.

FIG. 5 is a perspective view showing a modification of FIG.

FIG. 6 is a schematic explanatory view of a conventional fixing device.

[Explanation of symbols]

 1 Fixing Roller 2 Pressure Roller 3 Heater 4 Coating Felt 6 Cleaning Roller 8 Protrusion

Claims (3)

[Claims] 1. A fixing roller heated by a heating means, a pressure roller pressed against the fixing roller, a coating felt for coating an offset preventing liquid on the surface of the fixing roller, and a surface of the fixing roller is cleaned. A fixing device having a cleaning means for controlling the surface of the fixing roller and rotatingly driven in a direction opposite to the surface of the fixing roller, wherein the coating felt contacts the cleaning roller. A fixing device. 2. The coating felt according to claim 1, wherein a tip of the coating felt is in contact with the cleaning roller in a counter direction and a tip edge of the coating felt is inclined with respect to an axis of the cleaning roller. The fixing device described. 3. The fixing device according to claim 1, wherein the cleaning roller is provided with a spiral protrusion having a height of 1 mm or less on the peripheral surface over the entire width thereof.