JPS6042780A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent a floating toner from adhering, and to obtain a stable copy extending over a long period of time by enclosing a fixing roll by a prescribed cover, also providing vertically a flexible curtain member on the front well, and making this curtain contact to the surface of the roll. CONSTITUTION:A cover member 7 having an upper wall 14 and a rear wall 15 is provided on the upper part of a fixing roll 5, a flexible curtain member 8 is provided vertically along the length direction of the roll, on the front wall of the cover member 7, and it is provided so that its inside surface contacts to the roll 5. In this way, by enclosing the roll 5 by the cover member 7 and the curtain member 8, it is prevented that a floating toner adheres to the roll 5, a copying form 16 is not contaminated by a toner, and also it does not occur at all that the form winds itself round the roll 5. Therefore, a stable copy can be obtained extending over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixing device for use in equipment that utilizes an electrophotographic process, such as electrophotographic copying machines, facsimile machines, and printers.

[Prior art]

In conventional copying machines that use electrophotographic processes,
It is necessary to fix an unfixed toner image formed on copy paper to make a permanent image, and known fixing methods include a solvent fixing method, a pressure fixing method, and a heat fixing method.

The above-mentioned solvent fixing method uses a vapor or liquid solvent to dissolve the toner and infiltrate it into the fibers of the copy paper. Although it is more efficient than other fixing methods, the solvent vapor scatters and creates an odor. It is not widely used due to many hygiene problems.

In addition, the pressure fixing method is a method in which mechanical force is applied to the toner (in addition to adhering the toner to the copy paper), so it can be fixed with less energy, and has the advantage of being quick-start and high-speed. However, the fixing properties are worse than those of other fixing methods, and pressure-sensitive toner has the disadvantage that its manufacturing method is complicated and expensive, so the reality is that it has not been widely put into practical use. .

Therefore, for fixing unfixed toner images, a heat fixing method is generally used in which the toner is melted by heating and adhered to the copy paper.

Conventionally, this heat fixing method is a heat roll method in which fixing is carried out by applying a constant pressure between a pair of rolls (fixing roll and pressure roll), at least one of which is heated, and passing the copy paper having an unfixed toner image through it. This is known and is the most widely used because it has advantages over other heat fixing devices, such as lower power consumption and less risk of fire due to paper jams in the fixing section.

This fixing hole is made of polytetrafluoroethylene, HTV (heat vulcanization type) silicone rubber, RTV
(Room temperature vulcanization type) A roll whose surface is coated with a heat-resistant release material such as silicone rubber is used, and one pressure roll is used to maintain a certain contact width when it comes into pressure contact with the fixing roll. HTV silicone rubber, 1,
TV (low temperature vulcanization type) silicone rubber, RTV silicone rubber, fluororubber, EPDA rubber (Ethylene
Propylene Diene Acryl Rub
A material made of a heat-resistant elastic material such as ber) is used.

However, the biggest drawback of this heat roll method is that the toner side of the copy paper comes into direct contact with the surface of the fuser roll, so some of the unfixed toner on the copy paper is transferred to the fuser roll side, and that toner is transferred to the copy paper. A so-called offset phenomenon occurs in which the toner is retransferred to the trailing edge or to the next copy paper, staining the copy paper.

To prevent this phenomenon, a method has been adopted in which a release agent such as silicone oil is applied to the surface of the fixing roll, but this requires a tank for storing the oil and equipment for applying the oil, making the equipment more complicated. Not only does this result in an increase in size, but the oil also stains the copy paper.

For this reason, recently there has been a method of using a silicone roll with silicone oil kneaded into rubber as a fixing roll, and allowing the silicone oil to seep out from the roll surface during use.
A fixing device that does not require a supply device for a release agent such as oil has been put into practical use by incorporating in advance a treatment substance that improves release properties, such as low-molecular-weight polyethylene or low-molecular-weight polypropylene, into the toner. .

However, in fixing devices that do not apply these mold release agents,
Compared to devices that apply a release agent, there is a disadvantage that floating toner existing inside the main body of a copying machine easily adheres to and accumulates on the surface of the fixing roll and pressure roll. There was a tendency for the toner to accumulate in the areas on both sides of the fixing roll (1) where there was little chance of contact with the copy paper (2).

Therefore, when copying a large original, the toner (3) accumulated on both sides of the fuser roll (1) may be transferred to the copy paper and stain the copy paper, or in extreme cases, There was a problem in that the unfixed toner and the toner (3) deposited on the fixing roll (1) were fused together, causing the copy paper to wrap around the fixing roll (1) twice.

In addition, as shown in Fig. 2, the cleaning roll (1) is used to clean toner etc. adhering to the surface of the second roll (1).
4), the toner accumulated on both sides of the fixing roll (1) described above is cleaned and transferred onto the cleaning roll (4), so toner is not accumulated on both sides of the cleaning roll (4). As a result, the center of the cleaning roll (4) may float, and the accumulated and solidified toner may damage the surface of the fixing roll (1), resulting in poor toner adhesion on the copy paper. , there are disadvantages such as the occurrence of wrinkles on copy paper, and this disadvantage also occurs when a cleaning device using heat-resistant felt or the like is used instead of a cleaning roll.

[Purpose of the invention]

The present invention eliminates and improves the above-mentioned drawbacks of the prior art, and provides a fixing device consisting of a fixing roll and a pressure roll, in which at least the fixing roll is operated at a pressure of 1 bar. It is an object of the present invention to provide a fixing device which prevents floating toner from adhering to the fixing device and thereby provides copies with stable image quality over a long period of time.

[Structure of the invention]

That is, the present invention provides a fixing device that passes between a fixing roll and a pressure roll to scoop a fixed amount of toner, and at least above the fixing roll, a clay wall and a rear wall are provided along the length direction of the fixing roll. A flexible curtain member is installed along the length of the front end of the earthen wall of the cover member described in 1. By contacting the surface, floating toner is prevented from adhering to the surface of the fixing roll, thereby making it possible to obtain stable copies over a long period of time.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Incidentally, FIG. 8 shows an explanatory sectional view of the fixing device of the present invention.

That is, the fixing device of the present invention has two fixing rolls (5) and a pressure roll (6), and a fixing roll (5
) and a curtain member (8).

First, the fixing roll (5) has a cylindrical core metal (9) which is rotatably supported in the direction of the arrow as shown in FIG.
Room temperature vulcanizing (RTV) silicone rubber, heat vulcanizing (HTV) silicone rubber that covers the surface of this core metal (9),
It consists of a heat-resistant elastic layer (10) made of fluororubber, EPDA rubber, etc., and a fixing hole (5) is provided in the core metal (9).
A heater (11) for heating is provided.

On the other hand, the pressure roll (6) is provided below the fixing roll (5) and has a cylindrical core metal (12) like the fixing roll (5).
) and the heat-resistant elastic layer (13) that covers the surface of the core bar (12), and the core bar (12) rotates in the direction of arrow B as the fixing/goal (5) rotates. The fuser roll (5) and the pressure roll (6) are movably mounted and a suitable pressure is applied between them by a mechanism not shown.

The surface of the fixing roll (5) is coated on one side of the fixing roll (5) along its length, and the soil wall (14
) and a rear wall (15). A cover member (7) in the shape of a square is disposed, and the lower end of the rear wall (15) is connected to the fixing roll (5). ) and the pressure roll (6), it extends to a position where there is no problem when passing between the fixing roll (5) and the pressure roll (6), and covers the rear side of the fixing roll (5).

In addition, at the front end of the earthen wall (14) of the cover member (7),
A flexible curtain member (8) is hung vertically along its length, and its inner surface contacts the surface of the fixing roll (5), and its lower end is attached to a sheet of copy paper (16).
When the roller (5) passes between the fixing roll (5) and the pressure roll (6), the fixing roll (5) extends to a position where there is no problem.
) is configured to cover the front side of the

The cover member (7) is made of metal such as aluminum or heat-resistant plastic, and the outside thereof is coated with heat-resistant felt (not shown) to prevent burns.

Examples of the flexible curtain member (8) include heat-resistant sheets such as silicone rubber sheets and fluororubber sheets, polyimide, polyamideimide, polybenzimidazole, polyparaxylene, polyphenylene oxide, etc. Heat-resistant rubber sheets or resin films such as polyphenylene, phorysulfoni/, poly-4-methylpentene-1, and aromatic polyamide are used.

In FIG. 3, (17) indicates a copy paper separating claw attached to the fixing roll (5).

In order to fix the toner using the fixing device of the present invention, as shown in FIG. 6), thereby melting the unfixed toner and flowing it into the fibers of the copy paper (16), where it is cooled and fixed. At this time, the fixing roll (5
) Due to the action of the cover member (7) and curtain member (8), floating toner does not adhere to the surface of the copy paper (16), which prevents the copy paper (16) from becoming stained by floating toner, or the fixing roll ( 5) (There is no occurrence of double wrapping etc.)

By constructing the curtain member (8) with a material having both heat resistance and abrasion resistance, for example, a polyimide film, in addition to functioning as a member for preventing floating toner from adhering to the fixing roll (5), The curtain member can also function as a cleaning material for cleaning the surface of the fixing roll (5).

Here, in the above-mentioned embodiment (2), a cover member having a transverse channel shape is used, but the cover member used in the present invention is not limited to such a shape, and as shown in FIG. The cross section may be approximately arc-shaped as shown in FIG.
As shown in the figure, the length of the earthen wall (14) of the cover member (7) is shortened, and the fixing hood (5) of the curtain member (8) is suspended from the cut end of the upper wall (14). ) The structure may be such that the area in contact with the surface is widened.

In addition, in the second embodiment, only the fixing roll is covered with a cover member and a jy-ten member, but in an apparatus where floating toner is often generated, The lower end of the curtain part (8) may be extended to cover the pressure roll (6), and in some cases, the lower end of the rear wall of the cover member may also be extended to cover the pressure roll. The rear surface I11 may also be covered (not shown).In addition, if the lower end of the cover member etc. is extended to cover the processing roll, as shown in FIG. It is necessary to provide a passage opening (18) through which the copy paper passes approximately in the center of the bar gIS material, etc.

2. Although the present invention has been explained using a heat roll type fixing device as an example, the fixing device of the present invention is not limited to this heat roll type, and may be a roll type fixing device using a pressure fixing method. It can also be used in fixing devices. In this case, it is sufficient that the curtain member has flexibility, and heat resistance is not required.

〔Effect of the invention〕

As described above, in the present invention, due to the effects of the cover member and the curtain member, floating toner existing inside the main body of a copying machine or the like does not adhere to and accumulate on both sides of the fixing roll.

Therefore, various conventional troubles caused by floating toner can be solved by the present invention, and the replacement life of the fuser roll can be significantly extended. This can improve energy efficiency.

In addition, in the present invention, since a flexible curtain member is used, as shown in FIG. Therefore, the space on the front side of the fuser roll can be effectively utilized (7).Moreover, by using a curtain member that has heat resistance and abrasion resistance in addition to flexibility, the surface of the fuser roll can be The practical effects of the present invention are great, such as allowing the curtain member to function as a cleaning material.

[Brief explanation of drawings]

1 and 2 respectively show a plan view and a side view of a conventional fixing device, and FIG. 8 shows a cross-sectional view of the fixing device of the present invention, and FIGS. FIG. 6 is an explanatory diagram of a fixed stone device according to another embodiment, and FIG. 7 is an explanatory diagram of the operation of the present invention. Code explanation +1) (5+...Fuser roll (2+ (1
6)...Copy paper +3)...Toner +4+...Cleaning roll (6)...
...Pressure roll (7) ...Cover part (8)
・・・・・・Curtain member (9) f+2)・・・
...Core metal ao+l a3+...Heat-resistant bullet [biological layer (11)...Hea Z-(14)..."
7 Wall (15)...Rear wall (1ri...Copy paper separation claw (18)...Passway opening (19)
)... Parts Figure 1 Figure 4 (1 person)

Claims (1)

[Claims] In a fixing device that is provided inside the main body of an electrophotographic copying machine or the like and that passes a piece of copy paper on which an unfixed toner image is formed between a fixing roll and a pressure roll to fix the toner, at least the above-mentioned fixing device is provided. A cover member having an upper wall and a rear wall is disposed on one side of the fixing roll, and a cover member having an upper wall and a rear wall is disposed along the length direction, and a flexible wall member is provided at the front end of the earth wall of the cover member along the length direction. 1. A fixing device comprising: a vertical curtain member; the curtain member is brought into contact with the surface of the fixing roll;