JPH03119378A - Fixing device - Google Patents

Abstract

PURPOSE:To enhance the durability of a cleaning blade and to evade the occurrence of an abnormal image by providing a removing device and removing accumulation including toner and foreign matters in the cleaning blade. CONSTITUTION:A pair of rollers 1 and 2 heat-fix and unfixed toner image T on a sheet to be fixed 4. After fixing, toner and foreign matters are scraped away by the cleaning blade 8. This accumulation 10 such as toner and foreign matters occurs in a part where the top of the blade 8 abuts on the roller 1. Therefore, the removing device 13 is provided to remove the accumulation 10 in the part. A pressure roller 15 slightly presses a wound cleaner member 14 to bring the member 14 into contact with the roller 15, whereby the accumulation 10 including the toner fused on the side of the cleaner member 14 and foreign matters is attached to the member. Consequently, the durability of the cleaning blade 8 is enhanced and the occurrence of an abnormal image is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device that fixes a toner image on a sheet to be fixed by nipping and conveying the sheet to be fixed between a pair of rollers.

[Conventional technology]

In image forming devices such as copying machines and printers, a fixing sheet such as transfer paper or recording paper is conveyed between a pair of rollers, and the unfixed toner image formed on the fixing sheet is fixed. A fixing device is known.

FIG. 4 shows a conventional example of such a fixing device, in which one roller 10 of a pair of rollers 101 and 102 is
1 is provided with a heater 103 as a heat source, and a pressure roller 102 having an elastic layer such as a rubber layer formed on at least the surface portion is pressed against the heat fixing roller 101 provided with such a heat source. These rollers 101,1
02 are adapted to be rotated in the directions of arrows shown in the figure.

On the other hand, a sheet 104 to be fixed, such as a transfer paper or recording paper, on which an unfixed toner image T has already been formed is guided by guide plates 106 and 107 in a substantially vertical direction from bottom to top, while being guided by guide plates 106 and 107 on both sides. It is conveyed toward the nip between rollers 101 and 102. The sheet to be fixed 104 is
01 and 102, the unfixed toner image T is heated and fixed at the nip portion. After this fixing, the image is discharged outside the machine as copy paper or the like.

By the way, in this type of fixing device, when the toner image is heat-fixed, the toner image is fixed by the heat-fixing roller 1.
01, and this may be retransferred to the next fixing sheet. In order to prevent such retransfer of the toner image, a so-called release silicone oil for preventing offset is used to improve the releasability of the toner image from the roller. The reference numeral 109 indicates an oil-applied felt for applying such silicone oil to the heat fixing roller 101.

In addition to the releasing agent application means, such a fixing device uses a cleaning blade 108 made of an elastic material such as rubber.The tip of this blade is brought into contact with the circumferential surface of the heated fixing roller 101 to apply silicone oil. However, after fixing, toner and foreign matter adhering to the circumferential surface of the roller 1°1 are scraped off and removed. Here, the foreign matter refers to fine fibers of paper, and in addition to toner, such foreign matter also adheres to the surface of the roller 101. The cleaning blade 108 scrapes off and removes such foreign matter in addition to the toner.

In copiers that use a releasing agent such as silicone oil as mentioned above and a leaning blade, especially in high-speed machines that make a large number of copies, In addition, over time, scraped toner, foreign matter, and the like begin to accumulate on the portion of the cleaning blade 108 that contacts the roller 101.

What is indicated by the reference numeral 110 is such deposits such as toner and foreign matter.

If such a deposit is toner, the resin component that is the main component thereof cools and solidifies after the machine is turned off, and the deposit becomes lumpy over time. In such a state, for example, even if you turn on an image forming device such as a copier and start copying first thing in the morning, the toner itself is made of resin and has poor thermal conductivity, so it will not soften very quickly. ,
Since the particles remain in the form of lumps, the cleaning blade 108 may become distorted, making it impossible to effectively perform the cleaning function.

For example, it becomes impossible to uniformly remove toner and foreign matter remaining on the heat-fixing roller 101, and the toner and foreign matter pass through the tip of the cleaning blade 108, causing the oil-coated felt 109 and the heat-fixing roller to be removed. 101, and it becomes impossible to uniformly supply and apply a mold release agent such as silicone oil.

In such a state, the above-mentioned mold releasability deteriorates, and a large amount of toner and foreign matter accumulates at the cleaning blade 108.Furthermore, as the cleaning blade 108 passes through them repeatedly, the amount of silicone oil applied decreases. Toner, foreign matter, etc. may reach the metering blade 112, which is used to equalize the metering blade 112, and the equalizing function cannot be achieved.

The blade becomes floating and appears on the copy paper.
Oil streaks may occur. Furthermore, black streaks and the like occur on the copy paper due to the toner, and the cleaning blade 108, metering blade 112, etc. must be replaced due to the end of their service life.

[Problem to be solved by the invention]

Such a problem is caused by deposits 110 on the contact portion of the cleaning blade 108 with the heat fixing roller 101.
However, in the past, no means had been taken to remove the deposits in such areas.

An object of the present invention is to improve the durability of the cleaning blade by removing deposits such as toner and foreign matter from the cleaning blade portion, and to avoid the occurrence of abnormal images as described above. An object of the present invention is to provide a fixing device.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a fixing device that fixes a toner image on the fixing sheet by sandwiching and conveying the fixing sheet between a pair of rollers. A cleaning blade that scrapes and removes toner, foreign matter, etc. adhering to the peripheral surface of the roller; and a cleaning blade that scrapes and removes toner, foreign matter, etc. that have been scraped off and accumulated at a portion of the cleaning blade that contacts the roller from the accumulated portion. This paper proposes a configuration that includes a removal device that

Note that it is effective to make the removal device movable between a removal position where toner, foreign matter, etc. are removed and a non-removal position where it is not removed.

It is also advantageous to use a removing device that is moved to the removing position when a preset time has elapsed or when a preset number of sheets have been fixed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, numeral 1 is a heating fixing roller, 2 is a pressure roller, 3 is a heating heater, 6 and 7 are guide plates, 8 is a cleaning blade made of, for example, rubber, 9 is an oil-coated felt, and 12 is a metering blade. However, since these achieve the same functions as the members with the same name shown in FIG. 4, a functional explanation thereof will be omitted here. The unfixed toner image T on the fixing sheet 4 is heated and fixed by the pair of rollers 1 and 2 of the fixing device, and the toner and foreign matter after fixing are scraped off by the cleaning blade 8. Deposits 10 such as toner and foreign matter are deposited at the part where the tip comes into contact with the roller 1.
occurs.

A removal device designated by the reference numeral 13 removes the deposited lO from the deposited portion. The removing device 13 in this example has a cleaner member 14 that is wound up in the direction of the arrow. This is made of a heat-resistant material that has good adhesion to the toner, such as paper, plastic film, or non-woven fabric, and is lightly pressed with a pressure roller 15 to bring it into contact with the deposited area. Deposits 1o such as melted toner and foreign matter are made to adhere to the side of the member 14.

As the pressure roller 15, it is convenient to select a heat-resistant material such as rubber, metal, sponge, or plastic.

Conventionally, a device for removing such deposits was not provided, so toner, foreign matter, etc. passed through the cleaning blade 8 and accumulated on the oil coated felt 9, resulting in separation of silicone oil etc. Although there were cases in which the molding agent could not be applied uniformly, this problem is resolved in this example, and the mold release function can be performed satisfactorily and continuously. Also, the aforementioned “Oil Sujinoya”
This makes it difficult for "black streaks" to occur, and furthermore, the durability of the cleaning blade 8, metering blade 12, etc. increases.

The removal device 16 shown in FIG. 2 uses two cleaning rollers 17 and 18 to transfer deposits 10 onto these rollers, and then scrapes and removes the deposits 10 with a cleaning blade 19. In this example, the number of rollers is two, but the number of rollers may be one, three or more.

The removing device 21 shown in FIG. 3 uses an endless belt-shaped cleaner member 22 wound around a pair of rollers, and deposits 10 are attached to this, and then the cleaner member 22 is applied. The deposits are collected and removed using a cleaning blade or roller (not shown) that is in contact with the surface.

In each of the embodiments shown in FIGS. 1 to 3, the widths of the cleaner member 14, rollers 17, 18, and belt-like cleaner member 22 are set to be the same as the length of the heat-fixing roller 1 in the axial direction. Alternatively, the width of the image area may be adjusted to fit, for example, A4 size.Furthermore, a cleaner member or a cleaning roller may be installed at a certain distance from the end of the roller 1. Alternatively, the cleaner member, cleaning roller, etc. may be moved to the front side or the back side, and the attached deposit 1o may be dropped downward.

Note that a technique has been proposed in which the cleaning blade 8 is pulled out in the axial direction of the heating fixing roller 1 to remove toner accumulated on the cleaning blade, for example, as disclosed in Japanese Utility Model Application Publication No. 156968/1983. However, in this example, there is no need to move the cleaning blade 8, and the initial contact state is maintained.

By the way, if each of the above-mentioned removal devices is made movable between a removal position (positions shown in FIGS. 1 to 3) where toner, foreign matter, etc. are removed, and a non-removal position where they are not removed,
It is even more effective.

For example, the removal device is driven to the removal position when a predetermined set time has elapsed or when a preset number of sheets have been fixed.

In the embodiment shown in FIG.
The cleaner member 14 is moved in a direction to bring the cleaner member 14 into contact with and away from the deposit 10.

The contact timing for removing the deposit 10 is as follows.

After a preset time has elapsed, for example, after 7 to 8 hours, which is the average working time on -day, the machine may be turned off before the power is turned off. It is also possible to do this. In this way, the deposit 1o still remains in a softened state, and its removal becomes easy.

At such timing, for example, in the case of the pressure roller single drive system, the pressure roller 15 moves from the pressure release position to the pressure position shown in the figure, and in this state, the cleaner member 14 moves for example 10 to 20 meters in the direction of the arrow. It is wound up to a certain extent. After adsorbing the deposit 10, the pressure roller 15 rises and leaves the non-removal position. Incidentally, when a preset number of sheets have been fixed, for example, when approximately 20,000 sheets have been fixed, cleaning of the deposits as described above may be performed. After all, this is done periodically, for example, every 20,000 sheets.

Note that it is convenient to be able to change this timing depending on the copy specifications, the type of original, the quality of the fusing sheet used, the copy environment, and other various conditions. Furthermore, it would be convenient if it could be done by the user.

Regarding the specific leaning cycle, every day, 2~
It can be done every 3 days or every week.

- In the embodiment shown in FIG. 2, the desired function can be achieved by moving the entire removal device 16 up and down, or by moving the cleaning roller 17, cleaning roller 18, etc. up and down.

In the embodiment shown in FIG. 3, the desired function can be achieved by moving the belt-shaped cleaner member 22 in the direction of arrow B or by swinging the cleaner member 22 about the fulcrum 23. can be achieved.

Furthermore, in each of the above embodiments, in addition to the method of moving the removing device in the vertical direction, the removing device is moved in the front-back direction (in the axial direction of the heat-fixing roller 1) and brought to a position where it is removed from the roller 1. Alternatively, it may be driven to be displaced in an oblique direction.

By adopting the above configuration, the removal device is not always placed in the removal position, but is placed in the removal position only when necessary, which improves the durability of the removal device itself. , the durability of the cleaning blade 8 is also improved as in the previous embodiment.

By the way, FIG. 4 shows a conventional example of a fixing device.
04 is conveyed in a substantially vertical direction. When the fixing sheet 104 is conveyed in such a substantially vertical direction and passes between the rollers 101 and 102 while being guided by the guide plates 106 and 107, the unfixed toner image T is fixed. However, if the sheet to be fixed is vertically conveyed while being guided by the guide plate 107 or the like, when the sheet to be fixed 104 passes between both rollers 101 and 102, wrinkles may occur in the sheet to be fixed 104. Easy to occur. Especially not just on one side.

This tendency becomes stronger in the case of double-sided copying mode in which images are formed on both sides as well.

As in the embodiment shown in FIG. 5, the arrangement position and cross-sectional shape of the one-car guide plate 26 and 27 are as follows.
The above-mentioned problems can be made less likely to occur.

The guide plates 26 and 27 form a guide conveyance path for the sheet 4 to be fixed between the rollers 1 and 2.
In this example, the guide conveyance path is located close to both rollers 1 and 2 and directed toward the nip portion between them. The part where the direction of the conveyance path changes (the bending part) is approximately the part indicated by the symbol E, and is located directly below the heat fixing roller 1.
Of the guide plates 26 and 27, especially the guide plate 27 is tilted to the right as much as possible as shown in the figure, so that the sheet 4 to be fixed facing the rollers 1 and 2 is in a nearly horizontal state. It will be transported by

On the other hand, the cross section of the guide plate 27 has a shape as shown in FIG. In addition, FIG. 6 is a sectional view taken along the line X-X in FIG. 5, and in FIG. 5, the front side is the side a, and the back side is the
is on the side of As a result, the guide plate 27 has an arcuate surface with its widthwise central portion protruding toward the pressure roller 1 side, and its widthwise central portion is highest, and as it approaches both ends, it becomes a continuously curved surface. ing.

The guide plate 27 has such a surface, and furthermore,
Although it is tilted, the sheet to be fixed 4 is in a nearly horizontal position, so the weight of the paper acts and the sheet to be fixed 4 moves along the surface of the guide plate 27, and both rollers 1,
It will be sent to the nip between the two.

FIG. 7 shows a conventional horizontal type fixing sheet conveyance configuration, in which the guide plate 37 in a horizontal position similarly forms an arcuate surface that is located at the center in the width direction and is higher at the top and falls toward both ends. Both side edges of the sheet 4 to be fixed are brought into close contact with the surface of the guide plate 37 due to the paper's own weight, and are moved between the two rollers 1' and 2'.
caught in between. After all, in the case of the horizontal method, the sheet to be fixed 4 advances in a somewhat curved state, and this, combined with the effect that the paper becomes stiff, stabilizes its advancement, and both rollers 1 This makes it difficult for wrinkles to occur in the fixing sheet 4 between ' and 2'.

However, in the case of the vertical conveyance method shown in FIG.

It is not possible to effectively use the effect of paper's own weight,
Although it was easy to wrinkle, as shown in Fig. 5, the guide plate 2
6 and 27 as close to the horizontal position as possible, and by bringing the inflection portion E as close as possible to the roller side, the sheet to be fixed can be placed on the guide plate 27 even in the vertical type sheet conveyance method. The paper can be allowed to sag along the paper, that is, the paper's own weight can be used, and the occurrence of wrinkles can be suppressed. In FIG. 5, the bending portion E is provided directly below the heat fixing roller 1, but in the example of FIG. 1, if it is moved to the left side, the horizontal conveyance conditions can be further satisfied.

Note that the shape of the guide plate 27 does not necessarily have to be the same as the sixth one.
The shape is not limited to the one shown in the figure, but may be any shape that can utilize the weight of the paper, and does not necessarily have to be a smooth surface.

By configuring the guide plate in this manner, it is possible to further reduce the incidence of wrinkles, which are likely to occur especially in the duplex mode.

In addition, the configuration shown in FIGS. 5 and 6, and the configuration shown in FIGS.
It goes without saying that the fixing device can be assembled by combining the configurations shown in the figures.

〔Effect of the invention〕

According to the structure according to claim 1 of the present invention, since deposits such as toner and foreign matter are removed, unreasonable distortion is not applied to the cleaning blade, and its durability can be further improved. , the occurrence of abnormal images such as "black streaks" can also be suppressed.

According to the configuration described in claim 2, the removal device is displaced and driven to the removal position only when necessary, so that its durability can be improved.

According to the configuration described in claim 3, there is no need for an operator to press an operation button for instructing cleaning, and it is possible to contribute to a maintenance-free operation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of another embodiment, and FIG. 3 is a schematic diagram of another embodiment.
FIG. 4 is a schematic configuration diagram of a conventional example, FIG. 5 is a schematic configuration diagram of an embodiment in which the configuration of the guide plate for the fixing sheet is changed, and FIG. 6 is the X-XA of FIG. 5! The cross-sectional view, FIG. 7, is a diagram showing a horizontal conveyance system for a sheet to be fixed. 1.2...Pair of rollers 4...Fixed sheet 8...Cleaning blade 13.16, 21...Removal device

Claims (3)

[Claims] (1) In a fixing device that fixes the toner image on the fixing sheet by sandwiching and conveying the fixing sheet between a pair of rollers, toner that comes into contact with and adheres to the roller circumferential surface after fixing; A cleaning blade for scraping and removing foreign matter, etc., and a removing device for removing toner, foreign matter, etc. scraped and accumulated at the part of the cleaning blade that contacts the roller from the accumulated part. fixing device. (2) The fixing device according to claim 1, wherein the removing device is movable between a removal position where toner, foreign matter, etc. are removed and a non-removal position where the toner is not removed. (3) The fixing device according to claim 2, wherein the removing device is a removing device that is displaced and driven to a removing position when a preset time has elapsed or when a preset number of sheets have been fixed.