JPH02137872A - Heat fixing roll device for electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent the heat insulating layer of a heat roll from losing its heat insulation effect, deforming, and deteriorating and to improve its durability by forming the heat insulating layer in honeycomb structure by using a heat- resisting hard material. CONSTITUTION:The heat roll 11 has a rotary shaft 13, the heat insulating layer 15 formed on the surface of the rotary shaft, and a resistance heat generating layer 17 laminated on the surface of the heat insulating layer 15, which is formed in the honeycomb structure having many empty rooms 15b partitioned by a radial extending wall 15a made of the heat-resisting hard material. Thus, the heat insulating layer 15 has the honeycomb structure of the heat-resisting hard material to improve the rigidity without spoiling its heat insulation effect. Consequently, the heat roll 11 is prevented from deforming and deteriorating owing to temperature variation and the durability of the heat roll is improved.

Description

Detailed Description of the Invention [Object of the Invention] <Industrial Field of Application> The present invention relates to a heat fixing method for an electrophotographic apparatus in which a transfer means is heated and pressurized using a pair of rolls in order to fix a mapped image. Relating to a roll device.

<Prior Art> Conventionally, in an electrophotographic device using an electrophotographic process such as a copying machine, a heat fixing roll device that transfers toner to a transfer medium such as paper and then fixes the toner, uses a heating roll and a pressure bonding device. The rolls are brought into close contact with each other, and the transfer means is passed through the nip where both rolls touch each other, and the toner is heated and pressed onto the transfer means at the same time. For example, since it takes a long time to apply for a patent application filed by the same applicant,
No. 7279 discloses that a heating roll is provided with a heat insulating/elastic layer made of an elastic material such as silicone foam rubber, and a resistance heating layer which may be made of metal is formed over the entire surface of the heat insulating/elastic layer. structure is proposed. According to this structure, the above-described fixing operation can be performed by raising the temperature of only the resistance heating layer, so that the time required to raise the temperature of the heating roll is shortened.

Therefore, since the heat insulating/resilient layer is sealed between the rotating shaft and the resistance heating layer, and expands more than the resistance heating layer when the temperature rises, the resistance heating layer There is a problem in that the core layer deforms when the temperature drops because the core layer is compressed and the gas inside the heat insulating/resilient layer is forced out. There was also the problem that the silicone foam rubber and the like of the sealed heat insulating/resilient layer deteriorated due to expansion and contraction due to temperature changes of the heating roll.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main object of the present invention is to provide a heating roll having an internal heat insulating layer and a resistance heating layer on the surface. It is an object of the present invention to provide a heat fixing roll device for an electrophotographic device whose durability is improved without impairing the heat insulating effect of the layer and without deforming or deteriorating the core layer.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the object is to pass a transfer means between a heating roll and a pressure roll that rotate in close contact with each other, and to A heat fixing roll device of an electrophotographic apparatus for fixing a mapped image on the transfer target means, the heating roll comprising a rotating shaft, a heat insulating layer laminated on the surface of the rotating shaft, and a heat insulating layer laminated on the surface of the heat insulating layer. and a resistance heating layer, the heat insulating layer forming a honeycomb structure having a large number of cavities extending in the radial direction and partitioned by walls made of a heat-resistant hard material. This is accomplished by providing a heat fusing roll device for a photographic device.

Effect> As described above, by forming the heat insulating layer into a honeycomb structure made of a heat-resistant hard material, its rigidity is improved without impairing the heat insulating effect, and the heating roll is not deformed due to temperature changes.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the configuration of an electrophotographic apparatus to which the present invention is applied.

The rotatable photosensitive drum 1 has an outer peripheral surface plated with selenium. A charging section 2, a photosensitive section 3, a developing section 4, a transfer section 5, a cleaning section 6, and a static eliminating section 7 are provided along the outer peripheral surface of the photosensitive drum 1 in this order. Further, a fixing section 8 is provided downstream in the direction in which the transfer paper 9 is carried out from the transfer section 5, that is, in the direction of arrow A.

When the photosensitive drum 1 rotates in the direction of arrow B in FIG. 1, the surface of the drum passes through a charging section 2 consisting of corona charging means, and as a result, the drum surface reaches a uniform potential of about 700 volts. charged. Next, the surface portion of the photosensitive drum 1 passes through an exposure section 3, and a latent image corresponding to the shape of the subject is formed by exposure. Then, toner conveyed to a carrier (not shown) in the developing section 4 adheres to the surface of the photosensitive drum 1 in correspondence with the latent image. Further, in the transfer section 5, the transfer paper 9, which is conveyed in the direction of arrow A from the right side in FIG.
At the same time as being charged by a, the toner adhering to the surface portion of the drum 1 is transferred onto the paper 9. The surface portion of the photosensitive drum 1 after the toner has been transferred passes through a cleaning section 6, and residual toner is cleaned off. And a static eliminator 7 consisting of an exposure lamp
At this point, the static electricity is removed to approximately a negative potential in the axial direction, and the process described in 1 is repeated again. On the other hand, the toner transferred to the paper 9 is heated and pressed onto the paper 9 at the same time in the fixing section 8, so that the image is fixed on the paper 9.

FIG. 2 is an enlarged sectional view of the fixing section 8 of FIG. 1.

The fixing unit 8 includes a pressure roll 10 that is rotationally driven by a driving means (not shown) and a heating roll 11 that is driven by being in close contact with the pressure roll at a contact portion 12. The heating roll 11 includes, from its center to its outer periphery, a metal rotating shaft 13, a heat insulating layer 15 (to be described later), and a resistance heating layer 17 connected at an axial end to an external power source (not shown).
A protective layer 20 made of fluororesin is laminated in this order.

Moreover, an adhesive layer is provided between each layer of the heat insulating layer 15, the resistance heating layer 17, and the protective layer 20. This adhesive layer is applied to the resistive heating layer 17 during operation of both rolls 10.11.
and a layer for preventing the protective layer 20 from peeling off.

On the other hand, the pressure roll 10 includes a metal rotating shaft 21 and a rubber roll 22 fitted around the outer periphery thereof.

As shown in FIG. 3 when the heating roll 11 is viewed from the side, the resistance heating layer 17 is made of nichrome foil with a width of 5111 ol to 15III11 and a thickness of 20 μm to 80 μm.
It is adhered to the surface of the heat insulating layer 15. A spiral slit 18 is formed on the circumferential surface of the resistance heating layer 17. Further, the adhesive layer 19 between the resistance heating layer 17 and the protective layer 20 is made of a heat resistant resin whose thermal conductivity is slightly lower than that of the resistance heating layer 17, and this heat resistant resin fills the inside of the slit 18. There is.

As clearly shown in FIGS. 2 and 3, the heat insulating layer 15 of the heating roll 11 has a large number of hexagonal cavities 15b partitioned by walls 15a made of aramid resin extending in the radial direction.
It is formed by wrapping a sheet having a honeycomb structure around the rotating shaft 13. This empty space 15b provides a suitable heat insulation effect. Further, the wall 15a is hard,
Moreover, since it has a honeycomb structure, the rigidity of the heat insulating layer 15 is improved.

In reality, the honeycomb structure sheet may be formed of a heat-resistant hard material such as asbestos instead of aramid resin, and phenol resin, polyether ether ketone resin (PEEK), polyether sulfone resin ( PES
), a heat-resistant hard resin such as polyphenylene sulfide resin (PPS), melamine resin, polyimide resin, etc. may be molded into a cylindrical shape with a honeycomb structure and fitted around the outer periphery of the rotating shaft 13 to serve as a heat insulating layer. Furthermore, the large number of voids in the honeycomb structure of the heat insulating layer 15 may be triangular, quadrangular, circular, or the like.

FIG. 4 is a diagram similar to FIG. 2 showing a second embodiment based on the present invention. In this embodiment, a thickness of 2.5 mm is provided between the heat insulating layer 25 and the resistance heating layer 27 in order to reinforce the resistance heating layer 27.
A base resin layer 26 made of a heat-resistant resin of 0.0 cm or less is provided. In the first embodiment, in order to ensure the smoothness of the surface of the heat insulating layer 15, individual cavities 15b of a honeycomb structure are used.
However, according to this embodiment, the individual cavities 25b of the honeycomb structure in the heat insulating layer 25 can be increased to a certain extent. The other structure is the same as that of the first embodiment.

[Effects of the Invention] As described above, according to the present invention, by forming the heat-insulating layer of the heating roll into a honeycomb structure using a heat-resistant hard material, its rigidity is improved without impairing the heat-insulating effect. Therefore, deformation and deterioration of the heating roll due to temperature changes can be prevented, and the durability of the heating roll is improved.

From the above, the effects of the present invention are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus showing a first embodiment based on the present invention. FIG. 2 is an enlarged sectional view of the main part of FIG. 1. FIG. 3 is a partially broken side sectional view of the heating roll shown in FIG. 2. FIG. FIG. 4 is a diagram similar to FIG. 2 showing a second embodiment based on the present invention. 1... Photosensitive drum 2... Charging section 3... Exposure section 4... Developing section 5... Transfer section 6... Cleaning section 8... Fixing section 10... Pressure roll 12. ... Contact portion 15 ... Heat insulation layer 15b ... Vacant chamber 18 ... Slit 20 ... Protective layer 22 ... Rubber roll 25a ... Wall 26 ... Base resin layer

Claims (1)

[Scope of Claims] A heat fixing roll device of an electrophotographic apparatus for fixing an image of a subject on the transfer means by passing a transfer means between a heating roll and a pressure roll that rotate in close contact with each other. The heating roll has a rotating shaft, a heat insulating layer laminated on the surface of the rotating shaft, and a resistance heating layer laminated on the surface of the heat insulating layer, and the heat insulating layer extends in a radial direction. 1. A heat fixing roll device for an electrophotographic apparatus, characterized in that it has a honeycomb structure having a large number of empty chambers partitioned by walls made of a heat-resistant hard material.