JPS59129887A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent a scratch on the surface of a roller and a stain by oil and a toner of a supporting material by providing an adsorbing means of the supporting material which is wound round the fixing roller and carried on the surface of a separating roller. CONSTITUTION:Oil coated onto the fixing roller 7 is moved to an opposed roller 6 press-contacted to said roller. A guide plate 5 for guiding a supporting material 10 which is not wound round the roller but goes straight on, toward the downstream side is provided on the downstream side of a fixing part formed by a nip part of the fixing roller 7 and the opposed roller 6. A means for adsorbing the supporting material 10 which is wound round the fixing roller 7 and carried is provided on the surface of a separating roller 4. As for the adsorbing means of supporting material, the supporting material 10 is adsorbed electrostatically to the surface of the separating roller 4 by stronger force than adhesive force to the fixing roller 7 by setting the surface layer of the separating roller 4 to the electrostatically opposite polarity against the supporting material 10. As a result, it is possible to prevent a scratch on the surface of the roller due to a separating device, and the stain by oil and the toner of the supporting material.

Description

TECHNICAL FIELD The present invention relates to a fixing device in which a support 4;t (transfer paper) carrying an unfixed toner image is sandwiched and passed between fixing rollers that are in pressure contact with each other to perform fixing.

Prior Art In a roller fixing device that performs fixing by passing a support paper (transfer paper) carrying an unfixed toner image between a fixing roller and an opposing roller that are in pressure contact with each other, the surface layer of the roller is coated with silicone rubber or fluoride. It is made of a material with good release properties such as resin, and is coated with oil such as silicone oil to prevent offset of the toner image and to make it easier for the support material to sag from the surface of the roller. It is common to provide a separating device to separate the material from the roller surface.

Conventionally, as separation devices for this purpose, separation claws whose tips touch the roller surface have been widely used, but these separation claws may damage the roller surface or cause oil or oil that accumulates in the part of the separation claw that slides against the roller surface. The supporting material is easily contaminated with toner and the like. As a countermeasure, improvements have been made to the shape of the tip of the separating claw, or changes to the roller material have been made, resulting in scratches and oil (1.
Although the number of victims has been reduced somewhat, the current situation is that no fundamental countermeasures have been taken.

Purpose This invention eliminates the above-mentioned drawbacks of the support material separation device of the conventionally widely used minute g + M claw method, and can prevent scratches on the roller surface caused by the separation device and oil and toner stains on the support material. It is an object of the present invention to provide a roller fusing device with an image support material separation device.

Configuration The present invention will now be described in detail based on embodiments shown in the drawings.

In the embodiment shown in FIG. 1, a support material 10 carrying an unfixed toner image is conveyed by a conveyor belt 11 to a fixing device. The fixing device includes a fixing roller 7 and an opposing roller 6 that is in pressure contact with the supporting member 10 across a passage. The oil application roller 8 that presses against the felt part I'A9 impregnated with
It rotates following the rotation of the fixing roller and applies oil to the fixing roller. The oil applied to the fixing roller 7 is also transferred to the opposing roller 6 that is in pressure contact with the fixing roller 7.

On the downstream side of the fixing section formed by the nip section between the fixing roller 7 and the opposing roller 6, a supporting material 10 that is fixed and moves straight without being wrapped around the roller 7 is guided toward the feed roller 1. A guide plate 5 is provided.

A separation roller 4 is in contact with the periphery of the fixing roller 7 on the downstream side of the guide plate 5 . As shown in FIG. 2, the separation roller 4 is composed of a single shaft 4a parallel to the axis of the fixing roller 7, and a plurality of rollers 4b provided with gaps between them. The separation roller 4 can also be constructed by providing circumferential grooves on one roller at appropriate intervals. The surface of the separation roller 4 is provided with means for adsorbing the supporting material 10 that is being conveyed while being wrapped around the fixing roller 7 .

As a support material adsorption means, for example, as shown in FIG. 4, by making the surface layer of the separation roller 4 electrostatically opposite in polarity to the support material, the support material 10 is attracted to the separation roller 4 with a force stronger than the adhesive force to the fixing roller 7. What is necessary is to electrostatically adsorb it to the surface of. In the example shown in FIG. 4, the supporting material 10 is negatively charged, and a layer of a material that is positively charged is provided on the surface layer of the separation roller 4. In addition to this, as support material adsorption means,
As shown in FIG. 5, at least the surface layer 4c of the separation roller 4 is made of an elastic material such as rubber, and a number of recessed holes 4d are provided in the surface so as to press it against the fixing roller 7 with an appropriate pressure. Good too. By doing this, the separation roller 4
At the part where it comes into pressure contact with the fixing roller 7, the recessed hole 4d is deformed, the volume of its internal space is reduced, and the air inside is pushed out, and when that part is separated from the fixing roller 7 due to rotation, the volume of the recessed hole 4d becomes The original volume is restored and the internal pressure becomes negative,
The support material 10 in contact with this can be adsorbed onto the surface of the separation roller 4. A separation member 6 is provided between the separation roller 4 and the feed roller 1 to separate the support material 10 that is attracted to the surface of the separation roller 4 and conveyed, and guide it to the feed roller 1. In this embodiment, as shown in FIGS. 1 and 2, the separation member 6 has one end inserted into the gap or circumferential groove between the rollers 4b of the separation roller 4, and is attracted to the surface of the separation roller 4. A guide surface 3 that smoothly guides the supported material 10 being conveyed toward the feed roller 1
It is composed of a plurality of plate-like members 3a having a diameter b. As shown in FIG. 6, the separation member 6 also has a guide surface from the separation roller 4 to the feed roller 1 formed on the surface of a single plate 3c, and a gap between the rollers 4b of the official residence roller 4 or The claw-like protrusion 3d inserted into the circumferential groove may be provided so as to be smoothly continuous with the guide surface. Note that 2 in FIG. 1 is a guide plate.

Since this device is constructed as described above, the support material 10 carrying the unfixed toner image conveyed to the fixing device by the conveyor belt 11 is held in the nip portion between the fixing roller 7 and the opposing roller 6. While being transported, fixing is performed.

The tip of the support material 10 that has exited the nip portion is coated with the oil application roller 8.
When the fixing roller 7 is separated from the surface thereof due to the effect of the oil applied to the fixing roller 7, it is guided by the guide plate 5 and conveyed toward the feed roller 1.

If the supporting material 10 is not separated from the fixing roller 7 and is transported wrapped around it, it enters the nip between the separating roller 4 and the fixing roller 7 and is supported by the above-mentioned adsorption means on the surface of the separating roller 4. The material is separated from the fixing roller 7, adsorbed and held on the surface of the separating roller 4, and is conveyed while being wrapped around the circumferential surface of the separating roller. At 6', the separation part 6 whose tip is inserted into the gap or circumferential groove between the constituent rollers,
The support material is separated from the circumferential surface of the separation roller 4 and conveyed toward the feed roller 1 along the guide surface of the separation member B.

Note that the reason why the supporting material 1o is wrapped around the fixing roller 7 is mainly due to the adhesive force of the toner fused to the supporting material by heat and/or pressure, so there is a possibility that the supporting material 10 is wrapped around the opposing roller 6. Although it is small, if a similar support material separation device is provided for the opposing roller 6, wrapping around the opposing roller can also be prevented.

Effects As described above, according to the present invention, the support material can be supported reliably without causing scratches on the fixing roller or contaminating the support material with oil or toner, unlike conventional support material separation devices using separation claws. The material can be separated from the fuser rollers.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the overall general configuration of an embodiment of a fixing device to which the present invention is applied, FIG. 2 is a front view showing an embodiment of the fixing device, and FIG. FIG. 4 is a sectional view showing one embodiment of the support material adsorption means for the separation roller of the present invention, and FIG. 5 is a cross section showing another embodiment of the support material adsorption means for the separation roller. It is a diagram. 3...minute 2 (#bakeri 4...separation roller 4
a... Separation roller shaft 4b... Roller 4c constituting the separation 'F roller...
Separation roller surface layer 4d... Recessed hole 6... Opposing roller 7... Fixing roller 10... Toner image support material

Claims (1)

[Scope of Claims] (1) In a fixing device that performs fixing by passing a support material carrying an unfixed toner image between a fixing roller and a facing roller that are in pressure contact with each other, contacting the roller;
It may be constructed by installing a plurality of rollers on the surface of which are provided with means for adsorbing the supporting ions that are conveyed wrapped around the rollers, and provided on a single shaft with a gap between them, or a plurality of circumferential grooves. A separating roller configured as a single roller provided therein, and a separating roller having one end inserted into a gap or a circumferential groove between the separating rollers and having a guide surface that smoothly guides the supporting material that is attracted and conveyed to the separating roller. A fixing device comprising a member. (2) The fixing device according to claim 1, characterized in that the surface layer of the separation roller has a polarity electrostatically opposite to that of the support material as the support material adsorption means for the separation roller. . (6) As the supporting material adsorption means for the separation roller, at least the surface layer of the separation roller is made of a rubber-like elastic material having a large number of four-hole holes on the surface, and is pressed against the fixing roller. A fixing device according to claim 1.