JPH0481787A - Fixation device - Google Patents

Abstract

PURPOSE:To hold a lubricant, etc., such as grease on the internal surface of a film invariably constant and prevent the frictional force of the film internal surface from increasing with a rotation time by providing a lubricant coating control means such as a roller or scraper which has an uneven surface. CONSTITUTION:A driving roller 19 which drives the endless fixation film 18 is composed of a roller which is called a grid roller having ceramic powder adhered to its top surface. This grid roller is used for the driving roller 19 and then excessive grease applied over the internal surface of the endless film 18 enters gaps between particles of the grid roller, so that the internal surface of the endless film 18 is coated with only a necessary amount of grease. Consequently, the amount of grease is held constant without increasing nor decreasing the amount of grease previously or controlling the amount of grease periodically, and the frictional force on the film internal surface is prevented from increasing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heating type fixing device installed in an image forming apparatus such as an electrophotographic copying machine. The present invention relates to a fixing device that applies heat to fix images through a heat-resistant film.

[Prior Art] FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus equipped with a fixing device using a heat-resistant film.

1 is a document mounting table made of a transparent material such as glass, and is indicated by the arrow a.
Scans the original by moving back and forth in the direction.

A short-focus, small-diameter imaging element array 2 is arranged directly below the document placement table, and the image of the document placed on the document placement table 1 is illuminated by an illumination lamp 3, and the opposite light image is projected onto the array 2.
slit exposure is performed on the photosensitive drum 4. Note that this photosensitive drum 4 rotates in the direction of the arrow. A charger 5 uniformly charges the photosensitive drum 4 coated with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. The tram 4, which is uniformly charged by the charger 5, is subjected to image exposure by the element array 2 to form an electrostatic image. This electrostatic latent image is visualized by a developing device 6 using toner made of a resin or the like that softens and melts when heated.

On the other hand, the sheets P stored in the cassette S are transported to a tram by a pair of conveyance rollers 8 which are rotated while being pressed against each other in the vertical direction in synchronization with the image on the feed roller 7 and the photosensitive drum 4. 4 is sent above. and,
The toner image formed on the tourist drum 4 is transferred onto the sheet P by the transfer discharger 9.

Thereafter, the sheet P separated from the drum 4 by a known separating means is guided to a fixing device 11 by a conveyance guide 10, subjected to heat fixing processing, and then discharged onto a tray 12. Note that after the toner image is transferred, residual toner on the drum 4 is removed by a cleaner 13.

FIG. 6 shows an enlarged view of the fixing device 11. Reference numeral 14 denotes a low heat capacity linear heating element that is fixedly supported on the device, and for example, a resistive material 16 is coated on an alumina substrate 15 having a thickness of 1.0 mm, a width of 10 mm, and a length of 240 mm to a width of 1.0 mm. energized from both ends in the longitudinal direction. Power is DC1
With a pulse waveform of 00V and a period of 20 m5ec, a pulse corresponding to the desired amount of thermal energy release controlled by the temperature measuring element 17 is given by changing the pulse width. The approximate pulse width is 0.5 m5ec to 5 m5ec. The fixing film 18 moves in the direction of the arrow in the figure while coming into contact with the heating body 14 whose energy and temperature are controlled in this way. An example of this fixing film is a heat-resistant film with a thickness of 20 μm, such as polyimide, polyetherimide, PES,
PrpE and PA at least on the image contact side of PFA
A 10μm release layer made of a fluororesin such as F with a conductive material added.
It is a coated endless film. - The total thickness is less than 100 microns, preferably less than 40 microns, and the film moves in the direction of the arrow without wrinkles due to drive and tension by the drive roller 19 and driven roller 20.

Reference numeral 21 denotes a pressure roller having a releasable rubber elastic layer such as silicone rubber, which presses a heating element through the film with a total pressure of 4 to 7 kg, and the unfixed toner T on the transfer sheet P that rotates in pressure contact with the film is It is guided to the fixing section by the population guide 22, and a fixed image is obtained by the above-mentioned heating.

A lubricant such as grease is applied to the inner circumferential surface of the fixing film 18 in order to prevent an increase in friction between the fixing film 18 and the rollers 19, 20, etc.

The amount of grease applied to the fixing film is controlled by increasing or decreasing the amount applied in advance, or by intentionally applying it during the process.

[Problems to be Solved by the Invention] However, in the conventional example described above, there is a drawback that the amount of applied grease becomes smaller than the required amount over time, increasing friction. When applying grease, regularly control the amount of grease,
The disadvantage was that it had to be applied.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide a fixing device that can always apply an appropriate amount of grease to the inner peripheral surface of a fixing film without requiring troublesome management of the amount of grease. .

[Means for Solving the Problems] A configuration for realizing the object of the present invention is an endless rotation system in which a heat-resistant sheet member sandwiched between a heating element and a pressure member is wound around a plurality of rollers and rotated endlessly. A lubricant for preventing an increase in friction is applied to the inner peripheral surface of the endless belt, and a recording sheet carrying an unfixed toner image is placed between the heat-resistant sheet member and the pressure roller. In a fixing device that fixes the unfixed toner image by passing the unfixed toner image in close contact with the heat-resistant sheet member, the excess toner image applied to the inner circumferential surface of the endless belt is placed opposite to the inner circumferential surface of the endless belt. The present invention is characterized in that it has a lubricant application regulating means that can remove and store the lubricant and reapply the stored lubricant to the inner circumferential surface of the endless belt.

[Function] In the fixing device having the above configuration, when there is excess lubricant such as grease applied to the inner surface of the endless film, it is removed and stored, and when the amount of grease is reduced over time, it is removed in advance. This prevents an increase in friction by supplying the reduced or deleted grease and keeping the amount of grease constant without having to periodically manage the amount of grease.

[Embodiment] FIG. 1 is a schematic perspective view of essential parts showing an embodiment of a fixing device according to the present invention.

In this embodiment, a driving roller 19 for driving an endless fixing film (hereinafter referred to as endless film) 18 is constituted by a roller called a grid roller having ceramic particles adhered to its surface. As shown in FIG. 2, this grid roller 19 has a structure in which a base body 23 is coated with a make coat 24, ceramic particles 25 are arranged in a single layer, and a size coat 26 is coated to uniformly coat the particle adhesion areas. doing. By using this grid roller as the drive roller 19, an excess amount of the grease applied to the inner surface of the endless film 18 gets into the gaps between the particles of the grid roller, and in fact, the endless film The necessary amount of grease is evenly applied to the inner surface of the roller 18, and the grease that decreases with rotation time is removed from time to time by the grid roller, where the grease that has previously entered the gaps between particles is removed. Because it is applied, the amount of grease is always kept constant without increasing or decreasing the amount of grease in advance or managing the amount of grease regularly, thereby preventing an increase in frictional force on the inner surface of the film.

Here, the coarseness of the grid roller particles is #60 to #1
Although up to 000 is possible, #600 was determined to be optimal in this example due to damage caused by particles on the endless film 18.

Note that the driving roller 19 is not limited to a grid roller, but any roller having unevenness to the extent that it does not damage the endless film 18, such as a grooved roller or a blast roller, can achieve the same effect as in this embodiment.

Also, from the experiment, as shown in Figure 7, the grid roller (
@600) shows that the coefficient of friction μ between conventional rollers and the film decreases as the amount of grease increases.
This has the effect of keeping the value constant, which results in
It was found that there was no increase or decrease in the frictional force between the grid roller and the film due to an increase or decrease in the amount of grease.

FIG. 3 shows another embodiment.

In this embodiment, a scraper 27 is provided between the plastro roller 19 and the heating element 14 in order to uniformly and uniformly spread the amount of grease applied to the inner surface of the endless film 18.

This scraper 27 is spaced 0.05 mm from the endless film 18 in this embodiment because only a certain amount of grease is applied to the inner surface of the endless film 18. For this reason, grease is always applied to the inner surface of the endless film 18 by this 0.051+++n interval, and excess grease is stored in the inclined relief part a on the spacing flaper 2f. Furthermore, the grease stored in the relief part a is always in contact with the inner surface of the endless film 18 as shown in FIG. 4, and the grease in the relief part a reinforces the grease that decreases with rotation time.

Therefore, by providing the scraper 27, the inner surface of the endless film 18 can be kept in a constant state without having to increase or decrease the amount of grease or periodically manage the amount of grease. This prevents an increase in frictional force on the inner surface of the film.

In addition, the installation position of the soup scraper 27 is on the drive roller,
It is possible to apply it on the film in front of the heating element 14, and in addition, in order to prevent vibration between the endless film 18 and the heating element 14, increase the amount of grease between the film and the heater and reduce the frictional force. A soufflage scraper that applies the grease that has been stored for a while before the heating element 14 is also effective.

[Effects of the Invention] As explained above, according to the present invention, the lubricant such as grease on the inner surface of the film can be kept constant at all times by providing a lubricant application regulating means such as a roller or spray scraper with an uneven surface. Since the excess amount of grease of the grease that has been pre-applied is reinforced at any time, it is possible to prevent the frictional force on the inner surface of the film from increasing as the rotation time passes.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of essential parts showing an embodiment of a fixing device according to the present invention, FIG. 2 is an enlarged sectional view of a grid roller thereof,
FIG. 3 is a sectional view showing another embodiment, FIG. 4 is an enlarged sectional view of the main part thereof, FIG. 5 is a schematic diagram of an electrophotographic copying device, and FIG. 6 is a schematic diagram of a conventional fixing device. There is. FIG. 7 is a diagram showing the relationship between the amount of grease and the coefficient of friction. 18... Endless film 19... Drive roller 20... Followed roller 27
... Soufreper and 4 others Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A heat-resistant sheet member sandwiched between a heating element and a pressure member is wound around a plurality of rollers to form an endless belt that rotates endlessly, and the inner circumference of the endless belt is A lubricant for preventing increase in friction is applied to the surface of the recording sheet, and the unfixed toner image is placed between the heat-resistant sheet member and the pressure roller. In a fixing device that performs fixing by passing lubricant in close contact with the endless belt, a lubricant is placed opposite the inner circumferential surface of the endless belt, and removes and stores surplus lubricant applied to the inner circumferential surface of the endless belt. A fixing device comprising a lubricant application regulating means that can reapply the lubricant to the inner circumferential surface of the endless belt. 2. The fixing device according to claim 1, wherein the lubricant application regulating means is configured by providing irregularities on the outer peripheral surface of a roller around which the endless belt is wound. 3. The lubricant application regulating means according to claim 1 is a scraper provided opposite to the inner circumferential surface of the endless belt, and has a scraper disposed at the tip of the scraper opposite to the inner circumferential surface of the endless belt. A fixing device comprising a portion for storing excess lubricant.