JPH02115878A - Heat fixing roll - Google Patents

Abstract

PURPOSE:To eliminate fixing mark and to improve durability by providing a primer layer which contains whiskers and a release layer which is a polytetrafluoroethylene (PTFE) layer respectively at specified thicknesses to the heat fixing roll. CONSTITUTION:This fixing roll is constituted by providing the primer layer 3 having 3 to 10mu thickness and the release layer 1 having 5 to 40mu thickness on the surface of a cylindrical core bar 5. The primer layer 3 is formed by incorporating <=30wt.% metal or metal oxide whiskers 4 therein and the release layer 1 is formed as the PTFE layer contg. 1 to 10wt.% conductive SiC whiskers 2 and 5 to 30wt.% perfluoroalkoxy resin. The fixing roll which obviates the fixing mark and has the durability is obtd. in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a release layer on the surface of a fixing roll of a thermal roll fixing device.

[Prior Art] Conventionally, a heat roll fixing device has a configuration as shown in Fig. 2.
A mold release layer 1 is formed on the surface of the cylindrical cored metal 5, and the cylindrical cored metal 5
A fixing roll l with a heater 6 installed along the approximate central axis of
The press roll 11 was composed of a pressure roll 11 consisting of a roller and a layer 7 with a rough surface, and while the transfer paper was conveyed between the two rolls, the toner particles on the transfer paper were melted and fixed onto the transfer paper.

[Problems to be Solved by the Invention] Conventionally, fluororesins such as perfluoroalkoxy resin (hereinafter referred to as rPFAJ) and polytetrafluoroethylene (hereinafter referred to as rPTFEJ) have been used as a release layer on the surface of the fixing roll. There is, but.

In order to maintain the adhesive strength between the release layer and the cylindrical core, a primer layer must be provided between the release layer and the cylindrical core. The release layer and primer layer made of these resins have a significantly lower heat transfer coefficient than the cylindrical core metal, so
After the heat on the surface of the release layer is transferred to the transfer paper, there is a delay in heat replenishment from the cylindrical core metal, resulting in uneven fixing roll surface temperature, and the temperature control becomes thicker, resulting in uneven fixing performance. sometimes occurred. In order to improve the above problems, there is a way to make the release layer and primer layer thinner, but the primer layer needs to have a film thickness of about 4 to 100W due to manufacturing constraints such as pinholes. When made thinner, there was a drawback that durability due to wear was lost.

[Means and effects for solving the problems] The present invention has been made in view of the above, and the resin of the primer layer contains 30% by weight or less of metal or metal oxide whiskers, and the release layer contains 1 to 10% by weight of metal or metal oxide whiskers. % conductive SiC whiskers and 5-3
By using a fixing roll using a PTFE layer containing 0% by weight of PFA, it has become possible to reduce variations in roll surface temperature and improve durability.

The metal or metal oxide whisker used in the primer layer in the present invention has a length of 2 to 10 g and a diameter of 0.1 to 2.0 g.
The amount μ is preferably contained in the resin is 30% by weight or less, and 14% by weight or less; if it exceeds 30% by weight, the adhesion between the coating film and the metal core decreases, which is not preferable.

On the other hand, the conductive SiC whiskers used in the release layer are
Preferably, the length is 2 to 1O, the diameter is 0.1 to 2.0P, and P
The TFE layer contains 10i% of lN. If the content of the whisker is less than 1% by weight, a conductive effect is produced, and if it exceeds 10% by weight, the releasability of the toner decreases, which is undesirable.
The amount of PFA added to the PTFE layer is 5 to 30% by weight;
If it is less than 30% by weight, the surface smoothing effect will be small, and if it exceeds 30% by weight, offset will increase, which is not preferable.

The thermal conductivity of the resin layer varies depending on the type, shape, and amount of added substances. There are also restrictions in terms of stability, especially in the primer layer, if it is mixed in too much, the adhesive strength will decrease, and in the release layer, the mold releasability will decrease and toner offset will increase, so it is not desirable. In addition, if whiskers are mixed into the PTFE mold release layer and fired, the surface may become uneven or the whiskers may easily fall off from the surface layer due to the poor melt flowability of PTFE. In this case, P.T.
By mixing PFA with good melt fluidity into FH, the above drawbacks can be improved.

[Example] FIG. 1 shows one embodiment of the heat fixing roll of the present invention.

In FIG. 1, the surface of the cylindrical core metal 5 is coated with the primer layer 3.
It has been pre-blasted to increase the adhesive strength. The primer layer 3 contains 20% of iron oxide whiskers having an average diameter of 0.2 #L and an average length of 3 mm as metal whiskers, which is a feature of the present invention, and is coated to a thickness of 5 mm. The processed release layer has an average diameter of 0.
A PTFE layer containing 5% by weight of conductive SiC whiskers and 10% by weight of PFA with an average length of 51L and an average length of 5L was coated to a thickness of 20 bars, and then puff-polished to a roughness of IS. Finished the surface. Using the fixing roll manufactured with the above configuration, the surface temperature was regulated at 200°C.

When the fixing device was used, a good image without uneven fixation was obtained.

[Effects of the Invention] As explained above, by mixing conductive SiC whiskers and PFA in the release layer of the fixing roll and mixing highly thermally conductive metal or metal oxide whiskers in the primer layer, the temperature of the surface of the fixing roller can be reduced. Even if the heat is absorbed by the transfer paper and the heat decreases, the heat is quickly supplied from the cylindrical core metal to the surface layer of the fixing roll, thereby providing a durable fixing roll with no fixing unevenness.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of the surface layer of a fixing roll of the present invention, and FIG. 2 is a schematic sectional view of a heat roll fixing device. l... Release layer 3... Primer layer 5... Cylindrical core bar 7... Elastic layer 9... Cleaner 11... Pressure roll 2... SiC whisker 4... Metal Whisker 6... Heater 8... Core metal 10... Fixing roll

Claims (1)

[Claims] (1) Primer layer with a thickness of 3-10μ and a thickness of 5-40μ
of the mold release layer, and the primer layer contains 30% by weight or less of metal or metal oxide whiskers, and the mold release layer contains 1.
A heat fixing roll characterized in that it is a polytetrafluoroethylene layer containing ~10% by weight of conductive SiC whiskers and 5~30% by weight of a perfluoroalkoxy resin.