JPS6011353B2 - Oil application device for fixing roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil application device for a fixing roller of an electrophotographic copying machine.

The unfixed toner image formed by electrophotography is fixed by passing the copy paper carrying it through a heated fixing roller, and during this fixing, the molten toner image is To prevent the toner from adhering to the circumferential surface of the fixing roller and further offsetting and staining the copy paper, an anti-offset liquid (for example, silicone oil) is applied to the circumferential surface of the fixing roller.

Conventional methods for applying this oil to the fixing roller include methods that use only one application roller and methods that directly apply the oil using felt, but these methods have the drawback that it is difficult to adjust the amount of oil applied. One object of the present invention is to move the anti-offset liquid held in a container to the surface of the application member using a permeable member, such as felt, and reduce the amount of anti-offset liquid supplied to the material. An object of the present invention is to provide a fixing roller device whose adjustment is performed by adjusting the pressure of felt. Another object of the present invention is to use two rollers for applying oil to facilitate adjustment of the amount of oil applied to the fixing roller and to improve fixing.

To provide a device which removes toner offset from a roller and provides even oil application. The present invention will be explained below with reference to illustrated embodiments.

In the figure, a fixing roller 3 housing a pair of heaters 1 is constantly rotating in the direction of the arrow around an axis 2, and the image surface of the copy paper 4 carrying an unfixed toner image is rotated by the fixing roller. 3 and is conveyed in the direction of the arrow while being pressed against the circumferential surface of the fixing roller 3 by the pressure roller 5.

The application roller 7, which is provided with an offset prevention layer 6 of an elastic material (for example, silicone rubber) on its circumferential surface, is pivotally connected to a stationary member (not shown) by a shaft 8.
The application roller 7 is pressed against the fixing roller 3 by the elastic force of the elastic springs 12, each end of which is locked in the roller 1, and the application roller 7 is constantly rotated in the direction of the arrow by the frictional force caused by this compression. The oil adhering to the circumferential surface of roller 7 is applied to fixing roller 3. Further, a supply roller 14 having an offset prevention layer 13 of an elastic material (for example, silicone rubber) on its circumferential surface is rotatably and vertically movably supported by a shaft 15, and a coating felt 16 is provided on its upper circumferential surface. The free end 16a is in pressure contact. The pressing plate 17 arranged on the back side of the applied felt 16 is connected to the screws 18, 1.
The oil tank 21 is fixed to the oil tank 21 by 9, holds the felt 16, and stores oil 22.
A felt member 23 is fixedly installed inside, and the base of the coated felt 16 is in contact with the upper end thereof.

As a result, the oil 22 penetrates the coated felt 16 and reaches its free end 16a. Pressing plate 17
An adjusting screw 25 screwed into the fixed member 24 is provided at the free end of the
The ends of the lower legs are pressed against each other to apply appropriate pressure to both the lower legs 7 and 14. When there is sufficient oil 22 on the circumferential surface of the application roller 7, the frictional force between the two rollers 7 and 14 is extremely small, so the supply roller 14 is either stopped or rotates at a low speed. Is going.
When the amount of oil on the circumferential surface of the application roller 7 decreases due to the application action of the oil 22 on the fixing roller 3, the frictional force between the roller 7 and the supply roller 14 increases, causing the supply roller 14 to rotate significantly in the direction of the arrow. The oil 22 is supplied to the application roller 7.

In this way, the V-supply roller 14 rotates as appropriate in accordance with the increase or decrease in the frictional force generated between the rollers 7 and 14, so that a substantially constant amount of oil 22 is maintained on the circumferential surface of the application roller 7. Supplied. Also, the amount of these 9 pieces is 25 screws.
It can be easily adjusted by adjusting the tightening of the rollers 7 and 14 and the drumming force of both rollers 7 and 14. The conditions in which the feeding amount is adjusted by adjusting the tightening of the screw 25 are as follows. That is, when the screw 25 is tightened, the amount of movement of the anti-offset liquid within the coated felt 16 naturally decreases, so that the coefficient of friction at the contact surface between the free end of the coated felt 16 and the supply roller 14 increases.

Therefore, the rotation of the supply V-feed roller 14 is suppressed, and the amount of supply from the V-feed roller 14 to the coating roller 7 is reduced. On the other hand, on the contrary,
When the screw 25 is loosened, the amount of movement of the anti-offset liquid within the applicator felt 16 increases due to the promotion of capillary action, and the coefficient of friction between the free end 16a of the applicator felt 16 and the supply roller 14 at the rear surface increases. Since the supply roller 14 also becomes smaller, it becomes easier to rotate the supply roller 14, and as a result, the amount of supply by the supply roller increases. Since the offset prevention layers 6 and 13 are provided on both the rollers 7 and 14, the toner is not offset on the circumferential surface of each roller 7 and 14, and the toner is transferred to the coated felt 1 through the oil 22.
6 and is absorbed by the application roller 7 and the supply roller 1.
4, that is, the oil application action to the fixing roller 3 is performed smoothly.

The present invention makes it possible to adjust the amount of anti-offset liquid supplied to the coating roller by adjusting the pressing force of the coating roller against the fixing roller, so special means such as a blade is used to control the amount of liquid on the coating roller. The prevention liquid can be uniformly supplied without the need for an extremely simple structure. According to the present invention, although the application member absorbs the anti-offset liquid by capillary phenomenon until it becomes saturated after a long period of time, the clamping force exerted on the application member can be adjusted by the adjustment member, so that the anti-offset liquid is supplied. The amount can be adjusted, and not only is there no need to apply an excessive amount of the anti-offset liquid from the coating member, but there is also no staining of the toner support due to the anti-offset liquid. Further, according to the present invention, since an excessive amount of anti-offset liquid is not applied to the supply roller, there is no slippage between the fixing roller and the roller. Furthermore, according to the present invention, the fuser roller or the supply roller is coated with an anti-offset layer, so that even if an excessive amount of anti-offset liquid is applied to it, the fuser roller or the supply roller will swell and its life will be shortened. This also prevents the outer diameter of the roller from becoming uneven.

[Brief explanation of drawings]

The figure is a front view of an oil application device for a fixing roller showing an embodiment of the present invention. 3...Fixing low-fu, 7...Applying low-fu, 14...Supply V supply roller, 16...
...Applied felt, 22...Oil.

Claims (1)

[Scope of Claims] 1. A pair of rollers for fixing a toner image formed on copy paper, a container for containing an anti-offset liquid, and an anti-offset liquid directed toward at least one of the pair of rollers. a supply roller for supplying the offset prevention liquid; and a means for applying the anti-offset liquid to the supply roller; an adjustment member that is arranged at a position where it can be pressed against the roller and adjusts the pressing force of the application member against the supply roller, and the adjustment member adjusts the amount of movement of the anti-offset liquid in the application member and the An oil application device for a fixing roller, characterized in that the pressing force of an application member against a supply roller is adjusted.