JPH04134387A - Fixing device for electrophotographic device - Google Patents

Abstract

PURPOSE:To eliminate the need of blacking treatment to reduce the cost by giving ruggedness to the inside surface of a heat roll. CONSTITUTION:Ruggedness 30a is given to the inside surface of a heat roll 30 and a heater 32 like a halogen heater is provided in the hollow inside with respect to an electrophotographic device where a recording medium like a form 12 after transfer is heated by the heater 32 incorporated in the heat roll 30 while being carried by the heat roll 30 to fix a transfer image 35 on the recording medium 12. Consequently, the surface area to absorb the heat radiated from the heater 32 is extended. Thus, blacking treatment of the inside surface of the heat roll 30 is unnecessary to reduce the cost.

Description

[Detailed Description of the Invention] This invention applies to electrophotographic methods (transferring images formed on photoreceptors to recording media such as paper) using lasers, such as printers, copying machines, and facsimiles. It can be applied to an electrophotographic device that records on a recording medium using a method in which recording is performed using a recording method. Specifically, in such an electrophotographic apparatus, the present invention relates to a fixing device that fixes the transferred image on the recording medium by heating the recording medium after image transfer using a heater built in a heating roller.

Conventionally, in this type of fixing device, as shown in FIG. Paper 4 after transfer
There is a structure in which the transfer image 5 is fixed by applying heat and pressure to the paper 4 through the paper 4. And in this fuser,
In particular, the inner surface 2a of the heating roller 2 is black-dyed so as to efficiently absorb the radiant heat of the heater 1.This improves the thermal efficiency and allows the radiant heat of the heater 1 to be reflected on the inner surface 2a. This prevents the heater 1 from deteriorating due to reflected heat.

However, this conventional fixing device requires many work processes such as dyeing and drying processes, and also requires the cost of materials for black dyeing, which raises the problem of high costs.

Therefore, an object of the present invention is to reduce the cost of the above-mentioned fixing device.

- For this purpose, the present invention as set forth in claim 1 provides, for example, as shown in the illustrated embodiment below, while the recording medium such as the paper 12 after transfer is being conveyed by the heating roller 30, the heating roller 30 In a fixing device 21 of an electrophotographic apparatus that fixes a transferred image 35 on the recording medium by heating with a heater 32 built in the heating roller 30, an unevenness 30a is formed on the inner surface of the heating roller 30.
It is characterized by having the following.

Further, in the present invention as set forth in claim 2, for example, as shown in the illustrated embodiment below, in the fixing device 21 as set forth in claim 1, a pressure roller 31 is pressed against the heating roller 30. 31, heat and pressure are applied to the recording medium to fix the transferred image 35.

Furthermore, in the fixing device 21 of the present invention according to claim 1,
The transfer image 35 on the recording medium is fixed while heating the recording medium with the heater 32.

Further, in the fixing device 21 of the present invention, the transfer image 35 on the recording medium is fixed while applying heat and pressure to the recording medium by passing the recording medium between the heating roller 30 and the pressure roller 31.

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 4 is a laser printer equipped with a fixing device, which is an embodiment of the present invention, and shows the overall schematic structure of its internal mechanism.

Reference numeral 10 in the figure is the main body of the apparatus.

A paper feed tray 11 is detachably attached to the right side of the apparatus main body 1o in the figure. Paper (recording medium) 12 is stacked and stored in the paper feed tray 11 . And the top paper 1
2 against the paper feed roller 13. Then, the paper 12 is sent out in the six directions of the arrows in the figure by the paper feed roller 13, guided by the guide plate 14, and stopped by pressing the leading end between the pair of registration rollers 15. Then, as the drum-shaped photoreceptor 16 rotates, these registration rollers 1
5 and 15, and the photoreceptor 16 is activated at a predetermined timing.
send it towards.

The photoreceptor 16 is driven by a drive device (not shown),
Rotates clockwise in the figure. At this time, the surface is uniformly charged by the charger 17, and then the surface is irradiated with laser light from the optical writer 18 to form an electrostatic latent image there. Thereafter, when passing through the developing device 19 position, toner is deposited by the developing device 19 to visualize the electrostatic latent image.

The visible image is transferred to the photoreceptor 16 at a predetermined timing as described above.
The transfer charger 2° transfers the image onto the paper 12 sent to the paper 12. The paper 12 on which the visible image has been transferred is conveyed to the fixing device 21 of the present invention, where it is fixed by applying heat and pressure. Thereafter, the paper is discharged through the paper transport path 22 in the direction of arrow B and stacked on the paper discharge section 23.

On the other hand, after the visible image has been transferred to the photoreceptor 16, residual toner is removed by a cleaning device 24, and then the charge is removed by a charge removal brush 25.

By the way, in detail, as shown in FIG. 1, the above-mentioned fixing device 21 has a heating roller 30 and a pressure roller 31 disposed above and below, and the pressure roller 31 is appropriately biased by a biasing means to perform heating. It is pressed against roller 3o. The heating roller 30 is made of aluminum, for example, and is formed into a cylindrical shape by extrusion molding, and as shown in FIG. 2, the inner surface is provided with irregularities 30a having a triangular cross section. A heater 32 such as a halogen heater is provided inside the hollow space. On the other hand, the pressure roller 31 includes a roller shaft 33 provided with a roller portion 34 made of an elastic member such as rubber. Thus, the driving force of a drive motor (not shown) is transmitted to the heating roller 30, so that both the rollers 30 and 31 can be rotated.

Then, the paper 12 conveyed after the transfer is transferred to both rollers 3o.
- The transferred image 35 is fixed while applying heat and pressure to the paper 12 through the paper 12.

By the way, in the illustrated embodiment described above, the unevenness 30a has a triangular cross section, but as shown in FIGS. 3(A) and 3(B),
The cross-sectional shape of the unevenness 30a may be tooth-shaped or wave-shaped. Alternatively, the unevenness may be formed by knurling.

Therefore, according to the present invention, since the inner surface of the heating roller is provided with unevenness to increase the surface area for absorbing the radiant heat of the heater, unlike the conventional method, the inner surface of the heating roller is not dyed black. Even without processing, it is possible to efficiently absorb the radiant heat of the heater with a simple configuration, and the cost can be reduced. In addition, since the unevenness reduces the amount of reflected light that directly enters the heater, it is possible to reduce the amount of reflected heat to the heater and prevent its deterioration.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a fixing device according to an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view showing the unevenness of the inner surface of a heating roller in the fixing device, and FIGS. FIG. 4 is a partial cross-sectional view showing other examples of the unevenness, and FIG. 4 is an overall schematic diagram showing the internal mechanism of a laser printer equipped with the fixing device of the present invention. FIG. 5 is a schematic configuration diagram showing a conventional fixing device. 12... Paper (recording medium), 21...
...Fuser, 30...Heating roller, 30a...Irregularities, 31...
...Pressure roller, 32...Old...Heater, 35...
・・・・・・Transfer image.

Claims (1)

[Scope of Claims] 1. In a fixing device of an electrophotographic apparatus that fixes the transferred image on the recording medium by heating the recording medium after transfer with a heater built in the heating roller while conveying the recording medium with a heating roller,
A fixing device for an electrophotographic apparatus, wherein the heating roller is provided with unevenness on its inner surface. 2. Pressing a pressure roller against the heating roller and applying heat and pressure to the recording medium by passing it between the rollers;
2. A fixing device for an electrophotographic apparatus according to claim 1, which fixes a transferred image.