JP2849203B2 - Cleaning device for electrophotographic fixing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an electrophotographic fixing device that removes offset toner adhering to the surface of a fixing roller and applies an anti-offset liquid to the surface of the fixing roller. It is.

[Conventional technology]

A fixing device for electrophotography uses a cleaning device that slides a cleaning web impregnated with an anti-offset liquid onto the surface of a rotating fixing roller to remove offset toner on the surface of the fixing roller and simultaneously apply the anti-offset liquid. ing.

In a conventional cleaning device, a cleaning web drive feed mechanism is used to adjust a feed amount by attaching a brake or a cam mechanism to a complicated gear mechanism, or from a control circuit using a stepping motor or the like as a web winding motor. The feed amount is adjusted on the basis of the signal.

In many cases, the control of the cleaning web feed amount is performed in a complicated stepwise manner. After a certain number of copies are made, the web is transferred to a certain length and a new web surface impregnated with the offset preventing liquid is slid into contact with the fixing roller. Repeat that. Further, since the diameters of the web feeding roll and the web winding roll gradually change, when the rolls are simply driven at a constant rotation angle, the feed amount cannot be constant.

Therefore, the control mechanism for keeping the web feed constant is both a mechanical control mechanism and an electrical control mechanism, which are complicated and large, so that the main use is limited to expensive large-size high-speed electrophotographic apparatuses.

[Problems to be solved by the invention]

In an electrophotographic fixing device, a cleaning device that removes offset toner adhering to the surface of the fixing roller and applies an anti-offset liquid to the surface of the fixing roller is an important function that is indispensable for obtaining clean photos without contamination. is there. However, according to the prior art, there is a problem in that the transfer amount of the cleaning web must be controlled using a large-sized mechanism that is electromechanically complicated and expensive in order to sufficiently perform this function.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning apparatus capable of automatically controlling the transfer amount of a cleaning web by a simple, inexpensive, and small-sized mechanism that does not include any electrical control.

[Means for solving the problem]

In order to achieve the above object, in the cleaning device for an electrophotographic fixing device of the present invention, a web feeding roll for impregnating a cleaning web with an offset preventing liquid and feeding the same, a web winding roll for winding the cleaning web, A pressure roller between the two rolls for pressing the cleaning web against the surface of the fixing roller at a predetermined pressure; and a brake member for the web feeding roll, wherein the cleaning web is moved by rotation of the fixing roller, and the pressing roller Is driven by the movement of the cleaning web, the web take-up roll is configured to be frictionally driven by a core shaft that rotates following the pressing roller, and the friction between the pressing roller and the cleaning web is adjusted. The force is more than the frictional force between the fixing roller and the cleaning web The frictional force between the brake member and the payout roll is greater than the frictional force between the cleaning web and the fixing roller sufficiently wetted with the anti-offset liquid, but between the cleaning web and the fixing roller deficient in the anti-offset liquid. It is configured to have smaller frictional force.

Furthermore, in addition to the above-described configuration, a more reliable function is provided by providing a sub-brake member for the web take-up roll and configuring the frictional force of the sub-brake member to be equal to the frictional force of the brake member for the web pay-out roll. Will do.

In such a cleaning device for an electrophotographic fixing device of the present invention, in order to maintain the frictional force between the cleaning web and each roller at an appropriate value, an anti-offset liquid having an appropriate viscosity is selected and used. At the same time, it is desirable that the pressing force of the brake member and the auxiliary brake member against the web feeding roll and the web take-up roll and the pressing force of the pressing roller against the fixing roller be adjusted to appropriate values.

(Operation)

In the cleaning device for an electrophotographic fixing device configured as described above, since there is a layer of the anti-offset liquid between the cleaning web impregnated with the anti-offset liquid having an appropriate viscosity and the rotating fixing roller, the frictional force is increased. The cleaning web does not move due to the small braking force and the appropriate brake applied to the web unwinding roll, so that the web take-up roll does not work either. When the unfixed toner image on the copy paper is fixed by the rotation of the heated fixing roller in this state, the offset prevention liquid on the surface of the fixing roller adheres to the copy paper and is carried away, and the offset prevention liquid impregnated in the cleaning web. Is applied so as to replenish the fixing roller little by little. As the amount of the anti-offset liquid impregnated in the cleaning web decreases, the frictional force between the cleaning roller and the surface of the fixing roller that directly contacts the cleaning web increases as solid friction, and finally overcomes the braking force and the frictional force to clean the cleaning web. Lead to moving. At this time, the surface of the cleaning web that is in contact with the pressing roller is deficient in the anti-offset liquid, and the frictional force on the pressing roller surface is large. The core axis of the take-up roll rotates. Since this core shaft rotates while sliding with a friction torque between the core shaft and the web winding roll, even if the winding diameter becomes large, the core can be wound without being locked and without any slack of the cleaning web.

If a brake similar to the brake on the web feeding roll side is provided on the web take-up roll side so that both braking forces are substantially equal, it is more effective to keep the web feeding amount constant.

When the cleaning web is moved in this way, a new offset preventing liquid impregnated in the cleaning web is supplied to the surface of the fixing roller, and the frictional force between the cleaning web and the fixing roller is reduced by the lubricating action so as to fall below the braking force. Therefore, the movement of the cleaning web stops again.

In this way, the cleaning web is gradually transferred while repeatedly stopping the movement, and is wound up from the web feeding roll to the web winding roll.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, a fixing roller 1 is a pressure roller in which a surface of an aluminum hollow cylinder is covered with a layer of fluororesin and a heater 3 is provided inside, and an iron hollow cylinder is coated with a silicone rubber having a thickness of about 5 mm. The copy paper 5 rotates while being pressed against the print paper 2 to heat and fuse the unfixed toner 4 on the copy paper 5.

At this time, the anti-offset liquid applied to the surface of the fixing roller 1 in the form of a film prevents the toner from being offset to the fixing roller 1 and is absorbed by the copy paper 5. The cleaning device 17 wipes off stains while constantly replenishing the fixing roller 1 with a film of an offset preventing liquid.

The cleaning device 17 is composed of a web feeding roll 6, a cleaning web 19 impregnated with an offset prevention liquid sent out from the web, a web winding roll 8 for winding the web, and a slide for pressing the cleaning web 19 against the fixing roller 1. And a brake member 9 and a sub-brake member 9 ′ for braking the web feeding roll 6 and the web take-up roll 8 by the spring force of the brake spring 14, and a shaft of the pressing roller 7. Gears 11 and 13 are mounted on the core shaft 20, respectively, and the rotation of the pressing roller 7 is transmitted to the core shaft 20 via the idle gear 12, and the web winding roll 8 is rotated from the core shaft 20 while sliding with friction torque. Is rotated, and the pressing force of the pressing roller 7 is further reduced by a cleaning device.
A mechanism that adjusts with the force of the spring 16 in addition to the weight of 17 is adopted.

Further, in the present invention, the interlocking device using gears may be changed to a pulley and a belt, and the auxiliary brake member 9 'for the web take-up roll may be omitted.

In this embodiment, the force of the spring 14 is 500 gr / 2 kg, and the force of the spring 16 is 5
It was appropriate to pressurize at 00gr-1kg. As the anti-offset liquid, silicone oil having a viscosity of 10,000 CS was good. The moving amount of the cleaning web in this proper state was about 5 to 6 mm when 500 sheets of copy paper were passed.

〔The invention's effect〕

Since the present invention is configured as described above,
Without using a complicated and precise drive mechanism, drive motor, electric control circuit, etc. as in the conventional cleaning device, an appropriate amount of anti-offset liquid is appropriately supplied to the surface of the fixing roller, and the cleaning roller is automatically cleaned to an appropriate amount while cleaning the fixing roller. It can be moved and wound up.

As a result, the fixing device itself can be reduced in size and manufactured at a low cost, so that the fixing device can be mounted on a small-medium-sized copying machine. In addition, since the structure is simpler than the conventional cleaning device, the service life is extended, the amount of movement of the cleaning web can be reduced, the frequency of replacement can be reduced, and the inspection workability of the device is significantly improved. This has the effect of facilitating maintenance work.

[Brief description of the drawings]

FIG. 1 is an overall view showing the structure of a cleaning device for an electrophotographic fixing device of the present invention. 1 ... fixing roller, 2 ... pressure roller, 3 ... heater,
4 unfixed toner, 5 copy paper, 6 web feed roll, 7 press roller, 8 web take-up roll, 9 brake member, 9 'auxiliary brake member, 1
0,10 '... Support shaft, 11,13 ... Gear, 12 ... Idle gear, 14
…… Spring for brake, 15 …… Spindle for cleaning device,
16: Spring for pressing roller, 17: Cleaning device, 18
... fixing device, 19 ... cleaning web, 20 ... core shaft.

Claims (2)

(57) [Claims] 1. A web feeding roll for impregnating a cleaning web with an anti-offset liquid and feeding the cleaning web, a web winding roll for winding the cleaning web, and a cleaning web provided between the two rolls and having a predetermined pressure applied to the surface of the fixing roller. A pressure roller for pressing against the web, and a brake member for the web feeding roll. The cleaning web moves by rotation of the fixing roller. The pressing roller is driven by the movement of the cleaning web, and the web winding roll. Is configured to be frictionally driven by a core shaft that rotates following the pressing roller, and the frictional force between the pressing roller and the cleaning web is sufficiently larger than the frictional force between the fixing roller and the cleaning web. The frictional force between the brake member and the pay-out roll is offset-prevented. Wherein the frictional force between the cleaning web and the fixing roller is sufficiently larger than the frictional force between the cleaning web and the fixing roller, but is smaller than the frictional force between the cleaning web and the fixing roller lacking the offset preventing liquid. Cleaning device for fixing device. 2. An electrophotographic fixing device according to claim 1, further comprising a sub-brake member for the web take-up roll, wherein the frictional force of the sub-brake member is substantially equal to the frictional force of the brake member for the web feeding roll. Cleaning device.