JP3254117B2 - Image heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to an image heating apparatus for heating an the heated body by introducing the object to be heated between pressure member that presses therewith using a flat heating body, especially xerographic BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image heating apparatus for permanently fixing an unfixed toner image on a paper sheet used in a printer or the like.

[0002]

2. Description of the Related Art As a heating device, Japanese Patent Laid-Open No. 63-3131 is used.
No. 82, Japanese Unexamined Patent Publication (Kokai) No. 2-1577878, and the like have proposed a device using a heating element and a thin film having a high temperature rising rate.

FIG. 1 shows such a film heating apparatus. In the figure, reference numeral 1 denotes a flat heating element or heater manufactured by printing a resistor such as silver palladium or a conductor such as silver platinum on a glass paste on a base material such as ceramic by screen printing. is there. Reference numeral 21 denotes a support for supporting the heater, which is made of a resin having insulation and heat resistance, such as phenol resin, PPS, and liquid crystal polymer.

Reference numeral 22 denotes a reinforcing member for reinforcing the support and uniformly applying a pressure in the longitudinal direction, and is formed by bending an aluminum, SUS, or iron plate.

[0005] (3) A film base is made of a resin having high heat resistance and toughness such as polyimide, and PFA, PT
This is a fixing film formed by coating a fluororesin which is a heat-resistant release resin such as FE.

Reference numeral 4 denotes a pressure roller which covers a core metal with silicon rubber and further forms a fluororesin film on the outermost layer.

Reference numeral 5 denotes a recording material such as paper which is conveyed in the direction of the arrow, and enters the heating device with an unfixed toner image on it. The toner image is heated and pressed by the heating device, and is permanently fixed on the paper.

[0008]

In the above-described film heating apparatus, a lubricant such as grease is applied to smooth the relative movement between the heater and the film. However, this grease tends to be uneven on the inner surface of the film due to its high viscosity. This unevenness
In the initial stage of heating, unevenness in the temperature of the film is caused to cause deterioration of the image quality as vertical gloss unevenness in a half-loan image or the like. Figure 1 shows an example of this image.
0 is shown.

[0009] Further, excessive lubricant is protruded from the edge of the film and adheres to the surface of the film, which causes a decrease in the releasability or a trace of the lubricant on the paper to cause a deterioration in image quality. Had become.

[0010] The present invention is directed to a call to provide an image heating apparatus capable of preventing degradation in image quality due to the lubricant as described above.

[0011]

Means for Solving the Problems The first invention is a flat plate-like device.
A heating element, a support member for supporting the heating element,
The heating element through the film
And a pressurizing body for forming a nip, and passing the recording material through the nip.
In an image heating apparatus for heating an image on a recording material, the full
Lubricant is applied between the film and the heating element.
The surface of the support member on the recording material entry side has irregularities.
A lubricant diffusion portion is formed.

According to a second aspect of the present invention, a flat heating element and a heating element are provided.
A support member for supporting the
And pressurizing to form a nip with the heating element through the film
And a recording material passing through the nip to form an image on the recording material.
In the image heating device for heating, the film and the heating
Lubricant is applied between the body and the body.
Perpendicular to the running direction of the film on the recording material entry side
It is noted that a wavefront-shaped lubricant diffusion part
Sign.

A third invention is the above-mentioned second invention, wherein the expansion is performed.
A plurality of scattered parts are inclined toward the center in the longitudinal direction of the heating body.
Characterized by having the following groove.

According to the invention having the above-described structure , the lubricant does not partially accumulate in the film, and gloss unevenness does not occur on an image.

Further, in the third aspect, an image problem caused by seepage of the lubricant from the edge of the film is solved.

[0016]

DETAILED DESCRIPTION OF THE INVENTION (First Embodiment) First an example of an image forming apparatus using an image heating apparatus according to the present invention will be described with reference to FIG.

The photosensitive member 6 is a negatively charged OPC photosensitive member having a diameter of 24 mm, and is uniformly charged to -650 V by the charging roller 7 first. Next, the image portion is image-exposed by the laser exposure device 8, and the portion is discharged.

The developing section 9 undergoes reversal development with a negatively charged one-component magnetic toner. The developing device 9 uses a non-contact jumping developing method, and the developing sleeve includes:
-500V DC voltage and 1600Vpp, 1800Hz
Rectangular AC voltages are superimposed and applied. In this way, the developed toner image is approximately +2 to 3 kV.
Is transferred onto the paper 5 by the transfer roller 10 to which is applied, and is conveyed to the fixing device 50. The photoreceptor after the transfer is prepared for the next image forming step after the transfer residual toner is removed by the cleaner 11.

An example of the image heating apparatus used in the present invention will be described. The fixing film has an inner diameter of 24 mm and a thickness of about 40 μm of a polyimide base material.
m and about 10 μm of the surface layer of the fluororesin are baked.

The heater is formed by printing a silver palladium resistance heating element over a length of 220 mm with a longitudinal center distribution of 34Ω on an alumina substrate having a total length of 272 mm, a width of 7 mm and a thickness of 0.635 mm. The pressure roller forms a silicon rubber layer having a thickness of 3 mm on the outer periphery of an aluminum hollow core φ14, and its surface is coated with fluorine latex.

The pressure roller 4 is pressurized at a total pressure of 7.5 kg, and the heater mounting surface of the support 21 has a crown shape so that the nip width is uniform at the center and at the end.

Fluorine grease (trade name: Molycoat HP-300, trade name) is provided between the heater 1 and the fixing film 3.
(Dow Corning Asia Co., Ltd.) as a lubricant. Conventionally, when the fixing film was detached from the support 21 , as shown in FIG. 9, an uneven pool 13 of grease was recognized on the upstream side of the support of the heater. Such a state indicates that the grease is also unevenly applied on the fixing film.

[0023] Figure 2 is the embodiment of the present invention is provided with a number of bosses as a means for diffusing grease in the contact surface of the film of the support of the upstream side of the heater. The boss agitates the grease adhering on the inner surface of the film and spreads on the inner surface of the film so that the grease does not accumulate locally. Therefore, the heat capacity does not become uneven, and uneven gloss does not appear on the image. FIG. 3 is an enlarged view of the boss portion.

In the drawing, the portion where the boss is provided on the upstream side of the support has a width of 4 mm and a length of 230 mm, a diameter of the boss of 1 to 2 mm, a height of 0.1 to 0.5 mm, and a height of the boss. A density of 20-50 pieces / cm 2 was preferred for grease diffusion and film run stability. more than this,
Increasing or decreasing, decreasing, or increasing the number of bosses reduces the grease diffusion effect.

(Second Embodiment) FIG. 4 shows a second embodiment, in which a corrugated surface is formed on the contact surface of the support on the upstream side of the heater with the film. The traveling direction of the wavefront matches the traveling direction of the recording material or film. Due to this wavy surface, excess grease adhering on the inner surface of the film is scraped off and spreads along the valley of the wavefront in the longitudinal direction, so that it does not accumulate locally on the inner surface of the film. And no gloss unevenness appears on the image. In the first embodiment, since the number of bosses is large, the stirring direction of the grease is not determined. However, by making the grease wavy, the moving direction of the surplus grease becomes constant, and uniformization can be achieved more quickly. FIG. 5 is a view of the present invention viewed in a cross-sectional direction.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention, in which the wavefront is divided into two at the center of the support.
The direction of travel of the wavefront is each angled with respect to the direction of travel of the film or paper, and the line at the top of the wave is acute with respect to the direction of penetration of the paper. As a result, the grease is scraped off of the film at the top of the wavefront, and this excess is guided along the troughs of the wavefront to the center. This prevents the grease from seeping out from the end of the film, so that it is possible to prevent the toner image from offsetting, bleeding, or oil stains from appearing on the paper. FIG.
FIG. 3 is an enlarged view of a central portion of the present embodiment.

FIG. 8 shows a further improvement of this embodiment, in which the phase of the wavefront is shifted by 180 ° and the peaks and valleys are shifted. For this reason, the surplus grease at the center due to the first wavefront is transferred to the second wavefront and spreads along the valley when there is little grease on the second wavefront side. This has made it possible to apply grease evenly.

In the above embodiment, only up to two wavefronts have been described. However, two or more wavefronts may be alternately inclined. Further, although the cycle of the wavefront on the drawing is constant, it may not have a cycle. The numerical values of the dimensions, voltage, and the like are preferred examples.

[0029]

As described above, in the image heating apparatus according to the present invention, the lubricant adhering to the inner surface of the film is made uniform, the heat capacity of the film is made uniform, and the object to be heated is averaged. Heating can be performed, and contamination of the object to be heated can be prevented. In addition, the uniformity of the lubricant prevents gloss unevenness appearing on the image, thereby enabling a high-quality image to be obtained. In addition, the lubricant is prevented from leaking from the edge of the film, and the lubrication on the recording material is prevented. It is possible to prevent the trace of the agent and the offset.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image heating apparatus according to the present invention.

FIG. 2 is a schematic view of a first embodiment according to the present invention.

FIG. 3 is an enlarged view of the first embodiment according to the present invention.

FIG. 4 is a schematic view of a second embodiment according to the present invention.

FIG. 5 is a sectional view of a second embodiment according to the present invention.

FIG. 6 is a schematic diagram of a third embodiment according to the present invention.

FIG. 7 is an enlarged view of a third embodiment according to the present invention.

FIG. 8 is an enlarged view of a modification of the third embodiment according to the present invention.

FIG. 9 is a diagram showing a grease pool in a heating device of a conventional example.

FIG. 10 is a diagram showing an example of an image affected by a conventional grease pool.

Sectional view of an image forming apparatus using an image heating device according to Figure 11 the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heater 3 ... Fixing film 4 ... Pressure roller 5 ... Paper 6 ... Photoreceptor drum 7 ... Charging roller 8 ... Laser optical system 9 ... Developing device 10 ... Transfer roller 11 ... Cleaner 21 ... Support body 23 ... Boss 24, 25 … Is the top

Claims (3)

(57) [Claims] A flat heating element and a support for supporting the heating element.
Holding member, a film moving along the heating element, and a film.
A heating element and a pressure element forming a nip
And heat the image on the recording material by passing the recording material through the nip
In the heating device, a lubricant is applied between the film and the heating element.
The surface of the support member on the recording material entry side has an uneven shape.
Characterized by having a lubricant diffusion portion forming
Image heating device. 2. A flat heating element and a support for supporting the heating element.
Holding member, a film moving along the heating element, and a film.
A heating element and a pressure element forming a nip
And heat the image on the recording material by passing the recording material through the nip
In the heating device, a lubricant is applied between the film and the heating element.
Film on the recording material entry side of the support member
The wavefront-shaped lubricant diffusion section orthogonal to the traveling direction of
An image heating device characterized by being formed. 3. The heating device according to claim 1, wherein the diffusion portion is located at a center of the heating body in a longitudinal direction.
Characterized by having a plurality of grooves inclined toward
The image heating device according to claim 2.