JPS5817469A - Cleaning device for heat fixing roller - Google Patents

Abstract

PURPOSE:To utilize the scraping effect to clean the surface of a heat fixing roller well, by changing intermittently the relative speed of a cleaning member, which is brought into contact with the surface of the heat fixing roller of a heat fixing device and is rotated in accordance with the rotation of this roller, to the surface of the heat fixing roller. CONSTITUTION:The outside surface of a cleaning member is pressed to surfaces of heat fixing rollers 11 and 14 with an optimum energizing force determined on a basis of experiment. While the cleaning member is rotated in accordance with the rotation of heat fixing rollers, a brake or a damping mechanism using an electromagnetic clutch, a frictional clutch, and a centrifugal clutch, which is provided in a cleaning device, for the cleaning member is operated by the cleaning operatiok signal transmitted intermittently from a controlling part (which is not shown in figure), or an intermittently rotating mechanism using a Geneva gear, other gears, pins, etc. is used, thereby decelerating, stopping, accelerating, or reversing the cleaning member intermittently. Thus, the relative speed of the cleaning member is changed to exhibit the cleaning effect due to scraping for surfaces of heat fixing roller.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a means for cleaning the heat fixing area of a heat roll fixing device used in an electrostatic copying device, and more specifically to an improvement in the cleaning means using the scratching effect of the cleaning surface. Kill.

As a fixing method for electrostatic recording devices such as electrostatic copying machines, in recent years, p-Ra type fixing devices, such as heating p-ra type and pressure p-ra type, have been widely adopted.

For example, in a roller-type fixing device of an electrostatic copying device, fixing is performed while pressing the copy paper with four roller pairs. Therefore, since the surface of the roller and the image surface of the copy paper come into direct contact, toner tends to adhere to the surface of the roller. Therefore,
Various attempts have been made to prevent this so-called toner offset phenomenon. For example, four-
Applying a substance that prevents toner offset to the roller surface, or making the roller surface a material that makes it difficult for toner to adhere due to the composition of the roller, or making the offset prevention agent seep from inside the roller. Or, the toner itself is given an offset property. Hot offset and cold offset are also prevented by appropriately selecting the roller temperature and copy paper conveyance method.

However, even with these offset prevention techniques, it is extremely difficult to completely prevent toner from adhering to the fixing roller. Therefore, in the beginning, the anti-offset liquid application part # also had the function of a cleaning member, and the roller part was cleaned manually during machine maintenance and inspection. Regardless of the number of copies to be made, as the number of copies per sheet increases and high-speed mass-copying equipment is developed, problems arise in terms of machine maintenance, offset prevention efficiency, and the lifespan of coating materials. It has become necessary to independently provide a cleaning member around the fixing roller.

Cleaning members for the fixing roller include rollers, blades, webs, pads, and others.

Cleaning with rollers differs in surface energy,
That is, a method of transferring toner adhering to the surface of the fixing roller to the surface of the cleaning roller by utilizing the difference in adhesion force to the toner between the fixing roller and the cleaning roller;
Alternatively, there are two methods: using the fibrous irregularities provided on the surface of the cleaning roller to physically scratch the toner adhering to the surface of the heat fixing roller, that is, scraping, scraping, or wiping the toner off. It is used.

4IK A cleaning method that utilizes the second scratching effect is preferred; conventionally, a heat-resistant cloth is provided on the surface of the cleaning roller, and the cleaning roller is rotated relative to the heat fixing roller while being pressed against it (the direction of rotation is mainly (in the opposite direction) and cleaning the surface of the heat fixing roller was widely used.

The above-described method of providing a heat-resistant cloth on the surface of the cleaning roller has the advantage that the cloth is melted by the heat of the heat fixing roller, and therefore has better cleaning performance than other cleaning methods, and that the cloth lasts longer.

However, since the cleaning roller is rotated by forced drive, (1) the heat fixing roller is scratched, and (2) a large frictional force is generated between the heat fixing roller and the cleaning roller at the surfaces where they contact each other. Therefore, it has disadvantages such as (3) requiring a high-horsepower motor with a large dynamic torque, especially the starting torque at the time of starting the rotation, and (3) requiring a separate drive device to forcibly drive the cleaning roller. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning device for cleaning a heat fixing roller using a scratching effect, which does not have the above-mentioned drawbacks and has a good cleaning effect.

The object of the present invention described above is to provide a heat fixing roller free erasure device for a heat fixing device, in which the cleaning device is in contact with the heat fixing roller folding surface and can be driven by the roller, so that the cleaning member can be moved relative to the heat fixing roller surface. This can be achieved by a heat fixing roller cleaning device that is characterized by changing its speed intermittently.

Further, a preferred embodiment can be obtained by forming the cleaning member into a roller shape or by providing the cleaning surface with a fibrous cloth that is heat resistant and has adhesive strength to molten toner.

The present invention will be specifically explained below. The cleaning member of the cleaning device of the present invention may be of either a four-layer type or a belt type stretched over a plurality of rollers. Further, the outer surface of the cleaning member is pressed against the surface of the heat fixing roller by an optimum urging force determined through experiments. The cleaning device includes a drive device that independently drives the cleaning member, and the cleaning member can be driven by the rotation of the heat fixing roller.

The cleaning member is being driven by the heat fixing roller.

A cleaning activation signal sent intermittently from a control unit (not shown) activates a brake for the cleaning member attached to the cleaning device I, or a braking mechanism using an electromagnetic clutch, a friction clutch, and a centrifugal clutch. or by using the rotational force of the heat fixing roller to intermittently decelerate, stop, accelerate or reverse the cleaning member by using an intermittent rotation mechanism using gears, bottles, etc. ,
Change the relative speed of the cleaning member, which has been driven at zero relative speed to the heat fixing roller or at a slight or zero relative speed due to the intermittent rotation mechanism, to achieve a cleaning effect by scratching the surface of the heat fixing roller. can be done.

The braking mechanism may be activated by a signal from a copying machine etc. that is generated at a preset constant cycle, or it can be activated at a constant cycle immediately after warm-up and during idling, or after a certain number of copies have been made. It may be configured to do so.

Among the above-mentioned embodiments of the cleaning device of the present invention that changes the relative speed intermittently, an embodiment using a mechanical intermittent rotation mechanism will be particularly described.

In FIG. 1, 11 is a heat fixing roller that comes into contact with the toner bond carrying surface of the copy paper, 12 is a fixing roller paired with the heat fixing roller and holds the copy paper, and 13 is a cleaning roller.

Reference numeral 14 denotes a driving gear which extracts rotational force from the rotational shaft of the heat fixing roller 11 and has a rotational driving force, and 15 denotes a driven gear having a group of teeth meshing with the driving gear and which is connected to the cleaning roller 13 and one rotating shaft. be. The drive gear 14 has a convex peripheral surface t4t.
and teeth 142, and the driven gear 15 has a corresponding concave peripheral surface 15! and teeth 152.

While the convex circumferential surface t4t and the concave circumferential surface tSt are engaged, the cleaning roller 13 stops and the teeth 142 and ! When the rollers 52 are engaged, the cleaning roller 13 is allowed to rotate at a reduced speed, at a constant speed, or at an accelerated speed relative to the heat fixing roller IIK depending on the diameter ratio of the gears 14 and 15. Also, the cleaning time and number of times gear 13 stops is determined by
It can be adjusted by changing the ratio of the concave circumferential surfaces and convex circumferential surfaces of No. 4 and No. 15 and the teeth.

[Another embodiment is shown in Figure 2. In the figure, 21 and n are a pair of heat fixing rollers, 1 is a cleaning roller, and 2 is a drive wheel that generates the rotational force of the heat fixing roller, and has a pin 242 for driving and locking. Reference numeral 5 denotes a driven gear having teeth 25 and radial grooves 2 for responding to the movement of the bin 242.
53, and the tips of the teeth 252 form an arc concentric with the rotation circle of the pin 2420 around which the bin 242 can slide and rotate.

While the bin 242 is slidingly rotating on the circular arc, the driven gear is free, and therefore the cleaning roller n is also freely driven at a constant speed. The driven gear 6 and therefore the cleaning roller are braked when the cleaning roller 6 is being fitted into the housing or when the fitting is being disengaged. bottle 242
While pushing the base of the tooth 252, the cleaning fourth run n follows the heat fixing roller 211C, with deceleration depending on the conditions of the drive wheel U and the driven gear, and acceleration when the speed is constant.

In the intermittent rotation mechanism shown in FIG. 2, the direction in which the bottle 242 moves in and out of the radial groove 253 coincides with the direction of the groove 253 by 2y, so there is little impact and it is convenient for high-speed rotation.

The cleaning roller according to the present invention can be installed at either the downstream side or the upstream side of the fixing pressure contact section.

! l! FIG. 3 shows another embodiment. This embodiment employs a Geneva gear mechanism in which an intermediate gear is inserted between a driving gear and a driven gear, and the rotational force of the heat fixing roller is used to intermittently give the cleaning roller 414p of reverse rotation to the heat fixing roller. It is something.

In FIG. 3, 31 and ! (a) is a pair of heat fixing rolls, (a is a cleaning roller, A is a driving gear, A is a driven gear, whose teeth 352 are convex arcs and grooves 353 are concave arcs. A is an intermediate gear, It has teeth that mesh with the teeth of the drive gear, and a protrusion 362 that smoothly fits and responds to the arcuate teeth and grooves of the driven gear.

While the protrusion 362 is not in contact with the tooth 352, the driven gear A,
Therefore, the cleaning roller (freely heat fixing roller 31
The projection 362 is driven by the tooth 35 at a relative speed of zero.
2 and fits into the 'groove 353, the driven gear changes its direction of rotation, so that the cleaning roller, which has been driven by the heat fixing roller 31 in forward rotation, changes to reverse rotation. When the protrusion 362 further rotates and separates from the tooth 352, it returns to normal rotation driven state again.

The time, speed and number of reverse rotations can be freely selected by changing the gear conditions.

As explained above, the cleaning roller has its own drive device! l-The heat fixing roller can be driven in a decelerated, constant speed or accelerated state in the forward driven direction or reverse driven direction without intermittent button stops or fluctuations in relative speed with the driving roller. .

In the above embodiment, the cleaning ruler is mechanically rotated intermittently, but the cleaning ruler is periodically rotated based on, for example, the pressure signal of the thermal fixing a-ra from the copying machine, the number of optical scans, the count signal of the number of ejected sheets, etc. Brake pressure welding can also be performed.

The scratching effect of the above mechanism is influenced in part by the contact area of the cleaning roller surface with the heat fixing roller surface, that is, the degree to which the cleaning roller surface conforms to the convex arc of the heat fixing roller surface and deforms into a concave arc. Therefore, it is useful to cover the surface of the cleaning roller with a fibrous cloth that has both a scratching effect and deformability. Furthermore, the inside may be made of an elastic heat-resistant member such as silicone rubber. In addition, the scratching effect is caused by the fact that the fibrous cloth has an adhesion force to the molten toner, and if the fibrous cloth is melted by heat and appears to have an insulating structure, the heat of the heat fixing roller is wasted. Non-escape fibrous fabrics are preferred.

Preferred self-generated fibrous fabrics include fibers made of organic synthetic resins such as polyurea, polyacrylic acid, or polyamide, as well as inorganic fibers such as glass fibers, carbon fibers, metal fibers, and boron fibers. It is a fiber cloth made from a blend of

Further, the form of the fibrous cloth may be a woven fabric, a non-woven fabric, or a beaded fabric. If there is a risk of toner peeling off and falling from the pressure contact part of the cleaning roller! Detachable collection #, fX as shown in the tEA diagram
47 may be provided. Here, 43 is a cleaning material, 431 is a heat-resistant woven fabric such as Nomex, and 432 is an elastic material such as silicone rubber.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are explanatory diagrams of an embodiment of the cleaning device of the present invention in which an intermittent rotation mechanism is used. Figure tX4 shows a cleaning device in an embodiment of the present invention using a cleaning roller as a cleaning member. 11.4.31 and 41...Heat fixing roller,
13.23, 33 and 4...Cleaning roller, 14, drive gear for Sae and U, 15.5 and ah...driven gear, 47...
-・Collection member agent Yoshimi Kuwabara 13- 1 illustration, 21 illustrations

Claims (3)

[Claims] (1) In a heat fixing roller cleaning device for a heat fixing wall, the relative speed of the cleaning device to the heat fixing roller surface of the cleaning member that is in close contact with the heat fixing roller surface and capable of following the roller is intermittently changed. Features: Heat-fixing sealer cleaning equipment. (2) The heat fixing roller cleaning device according to claim 1, wherein the cleaning member is a roller-shaped member provided in parallel with the heat fixing roller. (3) The heat fixing device according to claim S (1) or (2), characterized in that the cleaning surface of the cleaning member is provided with a fibrous cloth that is heat resistant and has adhesion to molten toner. Roller cleaning device.