JP3029643B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fixing roller and a pressure roller that are in pressure contact with each other, an oil application member impregnated with an oil for preventing offset, and a rotation direction of the fixing roller. Means for supplying an offset preventing liquid to the surface of the fixing roller upstream of the oil applying member.

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, or the like, a transfer paper carrying a toner image is passed between a fixing roller and a pressure roller that press against each other to fix the toner image. In this case, it is inevitable that the toner of the toner image is offset to the fixing roller, and in order to prevent the offset, it is well known that the fixing roller is brought into contact with an oil application member impregnated with offset preventing oil by a leaf spring. It is.

[Problems to be Solved by the Invention] In the fixing device of the image forming apparatus described above, since the oil application member is in direct contact with the fixing roller, impurities such as offset toner and paper dust of transfer paper rotate the fixing roller. The oil coating member located at the most upstream position in the direction is blocked by the leading edge of the oil application member and easily accumulates there, and there is a disadvantage that the surface of the fixing roller is damaged by the accumulated impurities.

 An object of the present invention is to eliminate this inconvenience.

[Means for Solving the Problems] According to the present invention, the leading edge of the oil application member, which is in contact with the fixing roller and located at the most upstream in the rotation direction, is such that the central portion is located at the upstream in the rotation direction. Protruding into
The problem is solved by forming a triangular shape or an arc shape that is more downstream in the rotation direction as going toward both sides.

[Operation] At the leading edge of the oil application member located at the most upstream position in the rotation direction of the fixing roller, impurities such as toner and paper powder adhered to the surface of the fixing roller are blocked and accumulated, but at the same time, the surface of the fixing roller is The silicone oil dropped on the surface will also accumulate here. By inclining the shape of the leading edge according to the present invention, the impurities move along the leading edge toward the side edge of the oil applying member along with the silicone oil.

[Embodiment] In FIG. 1, a fixing roller 1 and a pressure roller 2 are arranged so as to press against each other and rotate in the direction of the arrow. 3 is a heater. Transfer paper 5 carrying toner image 4
Is passed between the fixing roller 1 and the pressure roller 2 via the guide plate 6, and the discharge roller pair 7 after fixing the toner image here.
Is discharged to a tray outside the machine. 8 has a separation claw, 9
Is an oil application device configured according to the present invention.

In the oil application device 9, one end of an oil application member 10 made of a felt material is folded and comes into contact with the fixing roller 1, and the other end is immersed in an offset prevention oil 12 such as a silicon oil put in an oil sample 11. ing. The contact portion of the oil application member 10 with the fixing roller is pressed against the fixing roller 1 by the leaf spring 13. in this case,
The contact portion is the first load position P _{1 at} the tip of the oil application member 10.
And it is strongly pressed from the plate spring 13 by a fixing roller 1 in the rotation direction at two positions of the second load position P ₂ on the downstream thereof. 14 is a support plate of the leaf spring 13, and 15 is a second cleaning member.

An oil tank 16 is arranged below the oil sump 11,
Further, an oil nozzle 17 is provided above the fixing roller 1. Silicon oil 12 in oil tank 16 is pumped
The oil 18 supplies the oil to the oil nozzle 17 via a conduit 19, and an appropriate amount is dropped from the oil nozzle. The silicone oil from the oil nozzle 17 falls onto the surface of the fixing roller further upstream from the leading edge of the oil application member 10 located at the most upstream in the rotation direction of the fixing roller.

In FIG. 2, the leading edge of the oil application member 10, that is, the leading edge 20 located at the most upstream in the rotation direction of the fixing roller, is shown.
Has a triangular shape protruding to be directed upstream in the rotation direction. That is, as shown in the figure, the oil applying member 10 has a triangular shape in which the central portion protrudes upstream, and becomes more downstream in the rotation direction toward both sides.
Instead of the triangular shape, the shape may be an arc shape, and the shape may also be made to protrude toward the upstream.

The impurities that are blocked and adhered to the leading edge 20 of the oil applying member 10 are released from the oil applying member by the silicone oil that has dropped from the oil nozzle 17 and reached the leading edge, and then formed to be inclined according to the present invention. The oil flows toward the both side edges of the oil applying member along the leading edge. At this time, the silicone oil permeates the oil application member 10, thereby ensuring that the oil application member applies the silicon oil uniformly to the surface of the fixing roller.

[Effects of the Invention] According to the present invention, the impurities accumulated on the leading edge of the oil application member are constantly transferred to the side, so that the occurrence of damage to the fixing roller surface due to the accumulated and attached impurities at the leading edge is prevented, and The configuration for that is simple.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a fixing device to which the present invention is applied, and FIG. 2 is a perspective view of a main part of the present invention. 1 ... fixing roller 2 ... pressure roller 10 ... oil application member 11 ... oil tank 12 ... silicone oil 20 ... leading edge

Claims (1)

(57) [Claims] A fixing roller and a pressure roller which are in pressure contact with each other, an oil applying member impregnated with offset preventing oil and brought into contact with the surface of the fixing roller, and an oil applying member as viewed in the rotation direction of the fixing roller. In a fixing device provided with means for supplying an offset preventing oil to the surface of the fixing roller at the upstream, a center portion of the tip edge of the oil application member, which is located at the most upstream in the rotation direction in contact with the fixing roller, is rotated at the center. A fixing device that protrudes upstream in the direction and has a triangular or arc shape that is more downstream in the rotation direction toward both sides.