JPS61221773A - Cleaning device of thermal fixing device - Google Patents

Abstract

PURPOSE:To generate no offset not only at the start time but also at the start time of after a warm-up by catching toner, paper powder, etc. which have adhered to the surface of a fixing roller, by a cleaning member through a cleaning roller. CONSTITUTION:A resin layer 1b and a rubber layer 2b of a pair of rollers 1, 2 offer an excellent mold releasing property, but it is impossible to prevent completely an offset phenomenon. Therefore, the first and the second cleaning rollers 13, 14 are provided with respect to the upper fixing roller 1 so that the lower fixing roller 2 and the first cleaning roller 13 are rotated in following up the upper fixing roller 1 which is driven, and the second cleaning roller 14 is rotated in following up the first cleaning roller 13. The first cleaning roller 13 is covered with a tube 13c consisting of polytetrafluoroethylene resin having the same mold releasing property as that of the resin layer 1b of the fixing roller 1. As for the second cleaning roller 14, an aluminum core 14a is covered with a pulp layer 14b whose mold releasing property is lower than that of the tube 13c of the first cleaning roller 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thermal fixing device adhesive IJ-ning device for thermally fixing toner to a toner carrier by a pair of thermal fixing rollers;
In a conventional thermal fuser, in particular a cleaning device of the type in which a cleaning roller is brought into contact with one of the fuser rollers, an offset phenomenon occurs, that is, the surface of the fuser roller opposite to the copy paper toner bearing surface of the heat fuser roller pair is The heat fixing roller is used to prevent the phenomenon in which the toner melted by the toner adheres and remains and is transferred to a different position on the toner-carrying surface of the copy paper, or transferred to the surface of the other fixing roller and then transferred to the back side of the copy paper. It is known, for example, from Japanese Patent Laid-Open No. 57-105760, to bring a cleaning roller into contact with one of the pair of fixing rollers.

These conventional devices are provided with one cleaning roller that is in contact with the fixing roller, and are capable of good wiping of toner, removal of paper dust from copy paper, and maintenance by adhering wiping toner and paper dust to the entire surface in a layered manner. It exhibits the characteristics of a longer cycle. Further, in the device described in the above-mentioned publication, the surface member of the cleaning roller is detachable and replaceable, so that maintenance can be easily and inexpensively performed.

If only one cleaning roller is provided in contact with the fixing roller as in the prior art, all of the toner and paper dust wiped from the fixing roller remains attached to the surface of the one cleaning roller. Moreover, the cleaning roller is always in pressure contact with the fixing roller. For this reason, when the fuser reaches a predetermined temperature during warming up before it is ready for use in a copying machine, etc., the toner adhering to the surface of the cleaning roller is heated and remelted at the contact area of the fixing roller. Therefore, it may adhere to the fixing roller and be transferred to the first copy paper, causing image noise.Also, even during the subsequent general startup, the fixing roller may remove adhering toner or paper from the cleaning roller. Physically scraping off the powder may result in reverse adhesion of toner or paper powder.

In order to solve the above problems, the present invention provides at least the fixing roller facing the toner carrying surface of the pair of heat rollers with a cleaning roller in contact with the fixing roller and a cleaning member in contact with the cleaning roller. The surface of the roller is made of a material with equivalent mold release properties.

Function: In general, toner and paper dust tend to migrate from parts with good mold release properties to parts with poor mold release properties, and among parts with equivalent mold release properties, from high temperature parts to low temperature parts. Paper dust and the like move from the surface of the fixing roller to the cleaning roller, and are then captured by the cleaning member.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which the upper fixing roller 1 of a pair of heat fixing rollers 1 and 2 is a heat roller having a built-in heater 3. In FIG. The lower fixing roller 2 is the upper fixing roller 1
For example, the toner image 5 on copy paper 4, which is fed between both rollers 1 and 2, is fixed under pressure and heat.

Roller vs weight.

A carry-in conveyor 6 and a carry-in guide 7 for feeding the copy paper 4 between the pair of rollers 1 and 2 are provided on the copy paper receiving side of the copy paper 2 . A separation claw 8 for separating the copy paper 4 from the upper fixing roller 1 is provided on the copy paper sending side of the pair of rollers 1 and 2, and a pair of rollers 9 for kicking out the copy paper 4 after separation. A pair of kicking rollers 9. After the fixing process, the copy paper 4 is sent out of a copying machine or the like or to the next process.

The upper fixing roller 1 is formed by covering an aluminum core 1a with a resin layer 1b made of polytetrafluoroethylene, and the lower fixing roller 2 is formed by covering an aluminum core 2a with a rubber layer 2b made of silicone rubber. It is formed. Further, a thermistor 12 is applied to the surface of the upper fixing roller 1, and a heater 3 is applied according to the surface temperature of the roller 1.
The current is controlled to a predetermined fixing temperature (usually 150 to 22
0℃).

Although the resin layer 1b and the rubber layer 2b of the roller pairs 1 and 2 exhibit excellent mold release properties, they cannot completely prevent the offset phenomenon.

Therefore, the first cleaning roller 13 in contact with the upper fixing roller l, and the first cleaning roller 1
3, the lower fixing roller 2 and the first cleaning roller 13 follow the upper fixing roller 1 which is driven, and the second cleaning roller 14 follows the first cleaning roller 13. I'm trying to get transferred.

The first cleaning roller 13 is provided with a layer of highly elastic foamed silicone rubber 13b on an aluminum core bar 13a in order to make full width contact with other rollers. It is covered with a tube 130 made of moldable polytetrafluoroethylene resin. The second cleaning roller 14 has an aluminum core 14a covered with a pulp layer 14b having a lower releasability than the tube 13C of the first cleaning roller 13.

As described above, the upper fixing roller l, the first . The releasability relationship on the surface of each of the second cleaning rollers 13 and 14 is as follows: Roller ■=Roller 13>Roller 14.

Also, the relationship between the surface temperatures is from the upper fixing roller to the first cleaning roller 13. Since heat is conducted from the first cleaning roller 13 to the second cleaning roller 14, roller 1>roller 13>roller 14 In a cleaning device with such a configuration, toner and paper powder adhering to the surface of the upper fixing roller 1 can be removed. Then, the cleaning roller 13 moves to the first cleaning roller 13 whose surface temperature is lower than that of the roller 1. At this time, the first cleaning roller 13 slips because it rotates while in contact with the upper fixing roller 1, and the nip formed by the elasticity of the first cleaning roller 13 scrapes off toner, paper dust, etc. act.

Toner and paper dust adhering to the surface of the first cleaning roller 13 are transferred to the second cleaning roller 4 and accumulated there due to the difference in release properties of the roller surface.

Actually, the diameter of the upper fixing roller 1 is 97M, the diameter of the lower fixing roller 2 is 80mm, the diameter of the first cleaning roller 13 is 50mm, and the diameter of the second cleaning roller 14 is 9QM.
When copying and fixing 100,000 sheets of A3 size copy paper 4 at a rate of 60 sheets/minute with M setting, there were image noises caused by direct offset from the upper fixing roller 1 to the copy paper 4 and lower fixing roller 2.
There was no offset to the back surface of the copy paper 4 via the roller, and furthermore, there was no toner or paper dust attached to the surface of the first cleaning roller 13.

FIG. 2 shows a second embodiment of the present invention, in which a cleaning blade 15 is pressed against the first cleaning roller 13 instead of the second cleaning roller 14 in the first embodiment.

The toner and paper powder adhering to the surface of the upper fixing roller 1 are transferred to the first cleaning roller 13 in the same manner as in the first embodiment.
The walls are removed by the cleaning blade 15i, and the receptacles are accumulated in the tray 16. The cleaning blade 15 is preferably made of heat-resistant, high-hardness rubber such as fluororubber or silicone rubber.

Since the other configurations are the same as those of the first embodiment, their explanation will be omitted.

In the present invention, the material of the surface of the fixing roller and the cleaning roller in contact with the fixing roller is not limited to the above-mentioned embodiments. For example, silicone rubber and other fluororesins can also be used, and in particular, tetrafluoroethylene resin can be used. (PTF
E) Fluororesins such as fluorinated ethylene propylene resin (FEP) and perfluoroalkoxy resin (PFA) have equivalent mold release properties, so they may be combined into the fixing roller and cleaning roller separately.

As explained above, according to the present invention, since the toner, paper powder, etc. adhering to the surface of the fixing roller are captured by the cleaning member via the cleaning flora, the adhering toner on the fixing roller remains for a long period of time. The toner is removed reliably at all times, does not cause offset during fixing, and there is no toner or paper powder adhering to the cleaning roller, so the toner between the fixing roller and the cleaning roller does not remelt when the device warms up. This does not occur, and no offset occurs not only at the time of starting, but also at the time of starting after warming up.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the invention, and FIG. 2 is a sectional view showing a second embodiment of the invention. 1.2...Heat fixing roller pair, 3...Heater, 13.
...First cleaning roller, 14...Second cleaning roller (cleaning member), 15...Cleaning blade (cleaning member) Applicant Minolta Camera Co., Ltd. Figure 1 1.2...! ! ! , Fixing Q-ra pair 3... and -13, -11 Cleaning roller 14... Potato 2 cleaning ゛a-ra Fig. 2/, 2... Soaked fixing roller force 3... Peter 13 ...'i$1 Cleaning roller 5...Cleaning 7゛Mood 16...Night group J1

Claims (1)

[Claims] 1. A cleaning roller in contact with the fixing roller and a cleaning member in contact with the cleaning roller are provided at least on the fixing roller facing the toner carrying surface of the pair of heat rollers, and the surfaces of the fixing roller and the cleaning roller are made of materials with equivalent release properties. A cleaning device for a thermal fixing device, characterized in that it is formed by: