JPH05113734A - Fixing device - Google Patents

Abstract

PURPOSE:To enable the use of commercially practicable silicone oil and eliminate defective image formation caused by a volatile component from the silicone oil. CONSTITUTION:A fixing device used for a multicolor image forming device is provided with a heating roller 1, a pressure roller 2, and a mold lubricant applying means 3 for applying dimethyl silicone oil 51 to the heating roller 1. The surface temperature of both heating roller 1 and pressure roller 2 is kept to the temperature of 190 deg.C at the fixing time. The dimethyl silicone oil 51 is extracted by a strip method in such a way that the density of each M2Dn body (n<=418), a low molecular component, is 50ppm or less and the density of each Dm body (m<=2), a low molecular component, is 50ppm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as an electrophotographic copying apparatus and an electrostatic information recording apparatus.

[0002]

2. Description of the Related Art Conventionally, as a multicolor image forming apparatus such as an electrophotographic copying apparatus, as shown in FIG. 6, a transfer material transporting apparatus is arranged in an area between one side of a main body 100 and a substantially central portion thereof. From the system I, the latent image forming section II arranged substantially in the center of the main body 100, and the rotary developing device III arranged between the latent image forming section II and the other side of the main body 100. There is one that is composed.

The transfer material transport system I includes transfer material supply trays 101 and 102 which are detachably mounted on the main body 100 through an opening provided on one side of the main body 100, and trays 101 and 102. Paper feed rollers 103, 104 arranged substantially vertically above and the rollers 103, 1
04, and the paper feed roller 10 is provided at both ends.
6, 107, a paper feed guide 24a, a paper feed guide 24b following the paper feed guide 24a, and the transfer drum 1
8 and the transfer drum 18 around the transfer drum 18.
8, a transfer material contact roller 17, a gripper 16, a transfer charger 29 and a transfer material separation charger 23, which are sequentially arranged in the rotation direction from the lower end to the upper end of 8, and above the paper feed guide 24a. Transport belt means 25 arranged,
A transfer material discharge tray 27 that is arranged on an extension of the terminal end of the transport belt means 25 and is detachable from the main body 100;
The fixing device 26 is provided between the conveyor belt means 25 and the tray 27.

The latent image forming section II is arranged so as to come into contact with substantially the upper end of the transfer drum 18 and the photosensitive drum 32.
And the photosensitive drum 32 is arranged around the photosensitive drum 32.
And an image exposing unit for forming a latent image on the outer peripheral surface of the charge removing charger 30, the cleaning unit 31, the primary charging unit 33, and the photosensitive drum 32, which are sequentially arranged from the upper end to the side end of the photosensitive drum 32. , Image exposure reflection means. The primary charger 33 is provided with an opening facing the photosensitive drum 32 and is electrically grounded to a shield plate 35 made of stainless steel, and a gold-plated tungsten having a diameter of 60 μm stretched in the center of the shield plate 35. The wire is made up of a primary wire 36 and a grid wire 37 made of a tungsten wire stretched over the opening of the shield plate 35.

The rotary developing device III includes a rotating body 34, a yellow developing device 34Y, a magenta developing device 34M, which is mounted on the rotating body 34 and visualizes or develops a latent image at a position facing the outer peripheral surface of the photosensitive drum 32. A cyan developing device 34C and a black developing device 34BK are provided.

When a full-color image is formed, the photosensitive drum 32 rotates in the direction of the arrow in the figure. A current is passed through the primary wire 36 of the primary charger 33, and corona discharge is performed in the direction toward the shield plate 35 and the direction toward the photosensitive drum 32. The photosensitive layer on the surface of the photosensitive drum 32 is uniformly charged by applying a predetermined voltage to the grid wire 37.

The image is exposed by the laser light E modulated by the yellow image signal of the original, and an electrostatic latent image corresponding to the yellow image is formed on the photosensitive drum 32. The electrostatic latent image corresponding to the yellow image is developed by the yellow developing device 34Y which is positioned in advance at the developing position by the rotating body 34 of the developing device III.

On the other hand, the paper feed guide 24a and the paper feed roller 10
7. The transfer material (not shown) conveyed through the paper feed guide 24b is held by the gripper 16 at a predetermined timing, and electrostatically transferred by the contact roller 17 and the electrode facing the roller. It is wound around the transfer drum 18.
The transfer drum 18 rotates in the direction of the arrow in the drawing in synchronism with the photosensitive drum 32, and the visible image developed by the yellow developing device 34Y is in contact with the outer peripheral surface of the photosensitive drum 32 and the outer peripheral surface of the transfer drum 18. It is transferred by the transfer charger 29 at the contact portion. The rotation of the transfer drum 18 is continued, and the transfer drum 18 is prepared for the next transfer.

On the other hand, the photosensitive drum 32 is discharged by the discharging charger 30 and the photosensitive drum 3 is cleaned by the cleaning means 31.
After the second cleaning is performed, the photosensitive drum 32 is charged again by the primary charger 33, and the photosensitive drum 32 is imagewise exposed with a magenta image. The developing device III rotates during image exposure on the photosensitive drum 32. Magenta developing unit 34M
Is moved to the developing position, and predetermined magenta development is performed.

Continuing with the above process, the cyan image,
Performed on black images. When the transfer of each color image is completed, the visible images of each color formed on the transfer material are discharged by the charging devices 22 and 23, and the gripper 16 releases the grip of the transfer material. Then, the transfer material is separated from the transfer drum 18 by the separation claw 24,
It is sent to the fixing device 26 by the transport belt means 25. In the fixing device 26, the visible image on the transfer material is heated and pressed to mix and fix the visible image.

As described above, the sequence of full-color image formation is completed, and the transfer material on which the full-color image is formed can be obtained.

Next, the color toner used in the image forming apparatus will be described.

The color toner is required to have excellent melting property and color mixing property when heat is applied thereto, and it is preferable to use a sharp-melting toner having a low softening point and a low melt viscosity. preferable. By using the sharp melt toner, the color reproduction range of the copy can be widened and a color copy faithful to the original image can be obtained.

Such a sharp melt toner is produced by melt-kneading, pulverizing and classifying a toner forming material such as a polyester resin, a styrene-acrylic resin, a colorant (a dye or a sublimable dye) and a charge control agent. To be done. If necessary, an external addition step of adding various external additives of the toner can be added.

As such a color toner, it is preferable to use a polyester resin as a binder resin in consideration of fixing property and sharp melt property. As the sharp melt polyester resin, a polymer compound having an ester bond in the main chain of a molecule synthesized from a diol compound and a dicarboxylic acid is exemplified.

In particular, the following structural formula

[0017]

[Chemical 1] (In the formula, R is an ethylene or propylene group, and x, y
Are each a positive integer of 1 or more, and the average value of x + y is 2 to 10. ) And a bisphenol derivative represented by the formula (1) or a substituted product thereof as a diol component, and a carboxylic acid component comprising a carboxylic acid having a valence of 2 or more or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, It is preferable to use a polyester resin obtained by at least copolycondensing phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) with sharp melting characteristics.

The softening point of the sharp melt polyester resin is 75 to 100 ° C., preferably 80 to 100 ° C.
It is preferable to select a sharp melt polyester resin having a temperature of 120 ° C.

The softening characteristics of the above-mentioned sharp melt toner will be described with reference to FIG. The measurement conditions are as follows.

For the measurement of the softening characteristics of the sharp melt toner, a flow tester CFT-500A type (Shimadzu Corporation) was used, and an extrusion load of 20 kg was applied with a die (nozzle) diameter of 2 mm and a thickness of 1 mm, and the initial setting was made. A plunger depression amount-temperature curve (hereinafter, referred to as "softening S time curve") is drawn when the temperature is 70 ° C. and the heating time is 300 seconds, and then the temperature is increased at a constant rate of 6 ° C./min. Ask. As the sample toner, 1 to 3 g of purified powdery toner is used. The cross-sectional area of the plunger is 1 cm ² .

As is clear from the softened S curve of FIG.
As the temperature rises at a constant speed, the toner is gradually heated, and the toner starts to flow (plunger descending A → B). When the temperature is further raised, the outflow amount of the molten toner increases (B → C → D), the descent of the plunger stops, and the process ends (D → E).

The height H of the softened S curve represents the total outflow,
The temperature T ₀ corresponding to the C point of H / 2 indicates the softening point of the toner.

Whether or not the toner and the binder resin have a sharp melt property can be determined by measuring the apparent melt viscosity of the toner or the binder resin.

Toner having such a sharp melt property
-Or a binder resin has an apparent melting temperature of 10³Poi
The temperature at which the₁, Apparent melting temperature is 5 × 1
0²The temperature at which the poise is shown is T ₂And when
It means one that satisfies the expressions (1) and (2).

90 ° C. ≦ T ₁ ≦ 150 ° C. (1) 5 ° C. ≦ | ΔT | = | T ₁ −T ₂ | ≦ 20 ° C. (2) The sharp melt resin having these temperature-melt viscosity characteristics is heated by heating. It has the characteristic of causing a sharp decrease in viscosity. Due to such a decrease in viscosity, proper mixing of the uppermost toner layer and the lowermost toner layer occurs, the transparency of the toner layer itself is rapidly increased, and good color-reducing mixing occurs.

Such a sharp-melting color toner has a great affinity, and an offset phenomenon in which the color toner is transferred to the fixing roller easily occurs. Therefore, the image forming apparatus using the above-described color toner is required to have a fixing device that maintains high releasability for a long period of time.

Next, the fixing device 26 used in this image forming apparatus will be described with reference to FIG. As shown in FIG. 8, the fixing device 26 includes a heating roller 1, a pressure roller 2 which is rotated while being in pressure contact with the heating roller 1, and a releasing agent which applies silicone oil as a releasing agent to the heating roller 1. The agent applying means 3 and the cleaning means 4 for cleaning the heating roller 1 are provided.

The heating roller 1 has a hollow cored bar 5 made of aluminum, and the outer peripheral surface of the cored bar 5 is covered with a silicone rubber layer 6. Silicone rubber layer 6 has a thickness of 2.8 mm
HTV (high temperature vulcanization type) silicone rubber layer and R having a thickness of 200 μm formed on the outer layer of the silicone rubber layer.
TV (room temperature vulcanizing type) silicone rubber layer. The outer diameter of the heating roller 1 is 40 mm.

The pressure roller 2 has a hollow cored bar 8 made of aluminum, and the outer peripheral surface of the cored bar 8 is covered with a silicone rubber layer 9. Silicone rubber layer 9 has a thickness of 1.0 mm
HTV (high temperature vulcanization type) silicone rubber layer. A fluororesin layer (not shown) is formed on the surface layer of the silicone rubber layer 9. The outer diameter of the pressure roller 2 is 40 mm. The pressure roller 2 is pressed against the heating roller 1 with a force of about 30 kg.

A halogen heater 7 as a heating source is arranged in the core metal 5 of the heating roller 1, and a core metal 8 of the pressure roller 2 is provided.
A halogen heater 11 is arranged inside.

The operation of each halogen heater 7, 11 is controlled by the temperature controller 12. The temperature control device performs on / off control for the operations of the halogen heaters 7 and 11 based on the surface temperature of the pressure roller 2 detected by the thermistor 12a. The surface temperature of the heating roller 1 and the surface temperature of the pressure roller 2 are maintained at a temperature of about 200 ° C.

The release agent applying means 3 is made of silicone oil 1
It has a container 13 in which 4 is housed. The silicone oil 13 is composed of silicone oil having a viscosity of 300 cs (KF96 300 cs manufactured by Shin-Etsu Chemical Co., Ltd.).
The silicone oil in the container 13 is supplied to the upper and lower supply rollers
It is pumped up by A and 15B and applied to the silicone rubber layer 6 of the heating roller 1. The amount of silicone oil applied to the silicone rubber layer 6 is adjusted by the application amount adjusting blade 10 that is in contact with the upper supply roller 15A. The amount of silicone oil applied to the heating roller 1 is 0.08 g / A4 in terms of A4 size transfer material.

The amount of silicone oil 14 applied is determined as follows.

That is, the weight of 50 sheets of A4 size white paper is A ₁ (g), and the nip portion is formed without transferring the image onto the white paper and applying the silicone oil to the silicone rubber layer 6 of the heating roller 1. The weight of 50 blank sheets after passing through the sheet is set to B (g), and the weight of other A4 size blank sheets is set to A ₂ (g), and the heating roller 1 is not transferred to the blank sheet. Assuming that the weight of 50 sheets of white paper after applying the silicone oil to the silicone rubber layer 6 and passing through the nip portion is C (g), the amount of silicone oil applied (g) per 1 sheet of A4 size paper is It is calculated by the following equation (3).

X = (C + A ₁ −B−A ₂ ) / 50 (3) The cleaning means 4 has a web made of Nomex (trade name), and the web is wound from the delivery shaft 4a via the pressing roller 4b. It is sequentially sent to the take-up shaft 4c. Pushing roller 4
At the position of b, the web is pressed against the surface of the heating roller 1, and the toner and the like adhering to the surface of the silicone rubber layer 6 of the heating roller 1 are removed by the web.

At the time of fixing, the transfer material P on which the unfixed toner image T is formed is conveyed in the direction of the arrow a by a conveying device (not shown) and the heating roller 1 rotated at a peripheral speed of 133 mm / sec. At the nip portion between the pressure roller 2 and the transfer material P
Is inserted. While the transfer material P passes through the nip portion, the unfixed toner image T on the transfer material P is fused on the transfer material P by heat and pressure, and a permanent image is formed on the transfer material P.

However, the surface temperature of the heating roller 1 is about 20.
Since the temperature is kept at 0 ° C., the silicone oil applied to the surface of the heating roller 1 is heated to a temperature of 200 ° C. The low molecular weight components in the silicone oil evaporate and the vaporized low molecular weight components fill the device. A part of the low molecular weight component filled in the apparatus adheres to the primary wire 36 of the primary charger 33, the reflection mirror, each sliding member, and the like.

By attaching the low molecular weight component of the silicone oil 14 to the primary wire 36, the primary wire 3
The unevenness in the corona discharge distribution due to 6 cannot be uniformly charged on the photosensitive drum, and the uneven charging occurs in a linear shape or a belt shape. Then, due to the linear and band-shaped uneven charging, linear or band-shaped uneven density occurs in the formed image.

Adhesion of the low molecular weight component of the silicone oil to the reflection mirror causes the reflection mirror to be contaminated, resulting in poor exposure of the photosensitive drum. The slidability of each sliding member is impaired by the adhesion of the low molecular weight component to each sliding member.

In order to suppress the evaporation of low molecular weight components in silicone oil, a method of using silicone oil from which low molecular weight components have been removed beforehand is disclosed in JP-A-41-9164.
7, JP-A-61-103931, JP-A-63-44.
681, JP-A-63-311372, JP-A 1-3
It is described in each publication of No. 11128.

Generally, silicone oil is represented by the following structural formula.

One is represented by the following structural formula as an M2Dn body.

[0043]

[Chemical 2] Note that n in the structural formula is an integer.

The other is represented by the following structural formula as a Dm form of cyclic siloxane.

[0045]

[Chemical 3] Note that m in the structural formula is an integer.

In the method described in each of the above publications,
A silicone oil in which low molecular weight components having small integers m and n in the above structural formula are removed beforehand is used.

[0047]

However, in recent years, the fixing speed has been increased by shortening the time for the transfer material P to pass through the nip portion between the heating roller 1 and the pressure roller 2. There is. To increase the fixing speed, the transfer material P
The surface temperature of the heating roller 1 is required to be maintained at 200 ° C. or higher in order to prevent the fixing failure due to the shortening of the passage time of the nip portion.

When silicone oil from which low molecular weight components have been previously removed is used in an image forming apparatus set so that the surface temperature of the heating roller 1 is kept at 200 ° C. or higher, the surface temperature of the heating roller 1 is 200 ° C. By being held above, the silicone oil applied to the surface of the heating roller 1 is heated to a temperature of 200 ° C. or higher, so that other low molecular weight components in the silicone oil that have not been removed in advance are evaporated. However, a part of the low molecular weight component evaporated in the device is the primary wire 36 of the primary charger 33,
It adheres to the reflection mirror and each sliding member.

Therefore, in order to suppress the evaporation amount of the low molecular weight component at a temperature of 200 ° C. or higher, it has been proposed to cut the low molecular weight component up to 25 classes for each integer n and m. However, even if the low molecular weight component in the silicone oil is cut by the conventionally known strip method, solvent washing method, supercritical extraction method, etc., the step of cutting the low molecular weight component by three or more steps as described above. It is necessary to repeat, and it is quite difficult in terms of time and cost for commercialization.

An object of the present invention is to provide a fixing device which can use commercially practical silicone oil and can eliminate defective image formation due to volatile components from the silicone oil. is there.

[0051]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a pair of fixing rotators which rotate while being in pressure contact with each other to form a nip portion for nip-conveying a transfer material; A release agent applying means for applying a release agent to at least one of the bodies is provided, and the unfixed developer image formed on the transfer material at the nip portion is heated and pressed to unfix the transfer material. In a fixing device for fixing a developing / development image as a permanent image, M2, which is a low molecular component of the release agent, is used.
The concentration of each Dn body (n ≦ 18) is 50 ppm or less, and the Dm body (m ≦ 2) which is a low-molecular component of the release agent.
This is achieved by keeping the respective concentrations of 0) at 50 ppm or less and keeping the heating temperature in the nip portion at 200 ° C. or less.

[0052]

In the fixing device of the present invention, the concentration of each of the low molecular weight M2Dn bodies (n≤18) of the releasing agent is 50.
ppm or less, the concentration of each Dm body (m ≦ 20), which is a low-molecular component of the release agent, is 50 ppm or less, and the heating temperature in the nip portion is maintained at 200 ° C. or less.

At the time of fixing, the release agent is applied to the one rotating body by the release agent applying means. The temperature of the release agent applied to the one rotating body is 200 ° C. or lower,
M2Dn, which is a low-molecular component in the release agent at 00 ° C
Body (n ≦ 18) and Dm body (m ≦ 2) which is a low-molecular component
The volatilization amount of 0) is very small.

The respective concentrations of the low molecular component M2Dn form (n≤18) are 50 ppm or less, and the respective concentrations of the low molecular component Dm form (m≤20) are 50 ppm.
The following release agents are manufactured by conventional strip methods and the like within a commercially feasible period and cost.

[0055]

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

FIG. 1 is a block diagram showing an embodiment of the fixing device of the present invention.

As shown in FIG. 1, the fixing device used in the multicolor image forming apparatus includes a heating roller 1, a pressure roller 2 rotated while being in pressure contact with the heating roller 1, and a heating roller 1. A release agent applying unit 3 for applying a release agent and a cleaning unit 4 for cleaning the heating roller 1 are provided.

The heating roller 1 has an outer diameter of 40 mm, and the pressure roller 2 has an outer diameter of 40 mm. The pressure roller 2 is pressed against the heating roller 1 with a force of about 50 kg. The pressure roller 2 cooperates with the heating roller 1 to form a nip portion for conveying the transfer material P under pressure.

A halogen heater 7 as a heating source is arranged in the core metal 5 of the heating roller 1, and a core metal 8 of the pressure roller 2 is provided.
A halogen heater 11 is arranged inside.

The operation of each halogen heater 7, 11 is controlled by the temperature controller 12. The temperature control device 12 performs on / off control for the operation of each halogen heater 7, 11 based on the surface temperature of the pressure roller 2 detected by the thermistor 12a. Surface temperature of heating roller 1 and pressure roller 2
The surface temperature of is maintained at 190 ° C. during fixing. The release agent applying means 3 has a container 13 in which dimethyl silicone oil 51, which is a release agent, is stored. Dimethyl silicone oil 51 is M2Dn which is a low molecular weight component.
So that the concentration of each body (n ≦ 18) is 50 ppm or less and the Dm body (m ≦ 20), which is a low-molecular component, has a concentration of 5 or less.
It is extracted by the strip method so as to be 0 ppm or less. In this embodiment, the dimethyl silicone oil 51 having a viscosity of 300 cs is used, but a dimethyl silicone oil having a different viscosity can be used.

Dimethyl silicone oil 5 in container 13
1 is drawn up by the upper and lower supply rollers 15A and 15B and applied to the silicone rubber layer 6 of the heating roller 1. Dimethyl silicone oil 51 for silicone oil rubber layer 6
The coating amount is adjusted by the coating amount adjusting blade 10 that is in contact with the upper supply roller 15A.

Next, the volatilization amount of the dimethyl silicone oil 51 will be described.

As a method for measuring the volatilization amount of dimethyl silicone oil 51, 2 g of dimethyl silicone oil 51 as a sample is placed in a beaker, dimethyl silicone oil 51 is heated to a predetermined temperature, and dimethyl silicone oil 51 is heated to a predetermined temperature. A method is used in which the temperature is maintained for a predetermined time and the amount of dimethyl silicone oil 51 volatilized during that time is measured. In this measurement, the holding temperature was set to 190
C. and 200.degree. C., and the holding time is 24 hours, 48 hours, and 72 hours for each holding temperature. The volatilization amount of the silicone oil used in the conventional fixing device was measured, and Table 1 shows a comparison between the volatilization amount of the silicone oil and the volatilization amount of the dimethyl silicone oil 51.

[0064]

[Table 1] As is clear from Table 1, the volatilization amount of dimethyl silicone oil 51 was 0.1% or less at each holding time at a holding temperature of 190 ° C., and the volatilization amount of dimethyl silicone oil 51 at a holding temperature of 200 ° C. It can be seen that it increases with the passage of. Holding temperature 190
The volatilization amount of dimethyl silicone oil 51 at a holding temperature of 200 ° C. is smaller than the volatilization amount of dimethyl silicone oil 51 at a holding temperature of 200 ° C., and the volatilization amount of dimethyl silicone oil 51 at each holding temperature is smaller than that of a conventional fixing device silicone oil. ..

During fixing, the dimethyl silicone oil 51 applied to the surface of the heating roller 1 is heated to 190 ° C. by the heating roller 1, but the volatilization amount of the dimethyl silicone oil 51 at the holding temperature of 190 ° C. is very small, The low molecular weight component of the dimethyl silicone oil 51 does not adhere to the primary wire of the primary charger, the reflection mirror, each sliding member (not shown) and the like. Therefore, it is possible to prevent the occurrence of linear or band-shaped uneven charging due to the adhesion of the dimethyl silicone oil 51 to the primary wire of the primary charger, and to prevent linear or band-shaped uneven density in the formed image.

The reflection mirror is not contaminated due to the adhesion of the low molecular weight component of the silicone oil to the reflection mirror, and the image exposure failure on the photosensitive drum due to the contamination of the reflection mirror does not occur. Further, the slidability of each sliding member is not impaired by the adhesion of the low molecular weight component to each sliding member. In this embodiment, it was confirmed that the image unevenness did not occur on 400,000 sheets of paper passing, and it is possible to prevent the image formation failure due to the volatile component of the dimethyl silicone oil 51.

Although the surface temperature of the heating roller 1 at the time of fixing is set to 200 ° C. in this embodiment, the surface temperature of the heating roller 1 and the pressure roller 2 at the time of fixing is kept at 200 ° C. The surface temperature of the heating roller 1 and the pressure roller 2 during standby can be maintained at 190 ° C. To reduce the fixing speed by keeping the surface temperature of the heating roller 1 and the pressure roller 2 at 200 ° C. at the time of fixing and keeping the surface temperature of the heating roller 1 and the pressure roller 2 at 190 ° C. at the standby time. Without, dimethyl silicone oil 51
The defective image formation due to the volatile components of Further, by lowering the surface temperature of the heating roller 1 and the pressure roller 2 during fixing and lowering the fixing speed, it is possible to maintain the fixing performance while further reducing the volatilization amount of dimethyl silicone oil.

Further, instead of dimethyl silicone oil, phenyl silicone oil, fluorosilicone oil, amino-modified silicone oil, etc. can be used.

Next, another fixing device will be described. FIG. 2 is a block diagram showing another embodiment of the fixing device of the present invention.

As shown in FIG. 2, another fixing device comprises a heating roller 1, a pressure roller 2 which is rotated while being in pressure contact with the heating roller 1, and a cleaning means 4 for cleaning the heating roller 1. ..

A halogen heater 7 as a heating source is arranged in the core metal 5 of the heating roller 1, and a core metal 8 of the pressure roller 2 is provided.
A halogen heater 11 is arranged inside.

The operation of each halogen heater 7, 11 is controlled by the temperature controller 12. The temperature control device 12 performs on / off control for the operation of each halogen heater 7, 11 based on the surface temperature of the pressure roller 2 detected by the thermistor 12a. Surface temperature of heating roller 1 and pressure roller 2
The surface temperature of is maintained at 190 ° C. during fixing. The cleaning means 4 has a web 52 impregnated with dimethyl silicone oil 51, and the web 52 is fed from the delivery shaft 4a through the pressing roller 4b toward the winding shaft 4c.

From the above, dimethyl silicone oil 5
Since 1 is impregnated in the web 52, the content of the dimethyl silicone oil 51 is small. Therefore, the dimethyl silicone oil 51 contains no low-molecular component, and the dimethyl silicone oil 51 contained in the web 52 contains It has been confirmed that the volatile content of the dimethyl silicone oil 51 is further reduced due to the small content, and a good image can be obtained up to 400,000 sheets.

In this embodiment, the dimethyl silicone oil 51 having a viscosity of 300 cs is used, but a silicone oil having a viscosity of 10,000 cs can be used instead. The concentration of each M2Dn body (n≤18) of this silicone oil having a viscosity of 10,000 cs is 50 p.
Dm body (m ≦ 2) which is less than pm and is a low molecular weight component thereof.
The respective concentrations of 0) are 50 ppm or less. When using this silicone oil with a viscosity of 10,000 cs, 4
It has been confirmed that image formation failure does not occur up to the passage of 0,000 sheets.

Next, another fixing device will be described. FIG. 3 is a block diagram showing still another embodiment of the fixing device of the present invention.

As shown in FIG. 3, the other fixing device applies a heating roller 1, a pressure roller 2 which is rotated while being pressed against the heating roller 1, and a dimethyl silicone oil 51 to the heating roller 1. A release agent applying unit 3 and a cleaning unit 4 for cleaning the heating roller 1 are provided.

The heating roller 1 has a hollow cored bar 5 made of aluminum, and the outer peripheral surface of the cored bar 5 is covered with a silicone rubber layer 6. The silicone rubber layer 6 is an HTV (high temperature vulcanization type) silicone rubber layer having a thickness of 2.8 mm, and an RT having a thickness of 200 μm formed as an outer layer of the silicone rubber layer.
V (room temperature vulcanizing type) silicone rubber layer. The thermal conductivity λ of the silicone rubber layer 6 is 1 × 10 ^-3 cal / sec.cm.d.
is eg. The outer diameter of the heating roller 1 is 40 mm.

The heating roller 1 is soaked in dimethyl silicone oil having a viscosity of 300 cs and the silicone rubber layer 6 is impregnated with dimethyl silicone oil in order to further improve the releasing property.

The pressure roller 2 has a hollow cored bar 8 made of aluminum, and the outer peripheral surface of the cored bar 8 is covered with a silicone rubber layer 9. The silicone rubber layer 9 is composed of an HTV (high temperature vulcanization type) silicone rubber layer having a thickness of 1.0 mm. A fluororesin layer (not shown) is formed on the surface of the silicone rubber layer 9. The outer diameter of the pressure roller 2 is 40 mm. The pressure roller 2 is pressed against the heating roller 1 with a force of about 50 kg. The pressure roller 2 cooperates with the heating roller 1 to form a nip portion for conveying the transfer material P under pressure.

A halogen heater 7 as a heating source is arranged in the core metal 5 of the heating roller 1, and a core metal 8 of the pressure roller 2 is arranged.
A halogen heater 11 is arranged inside.

The operation of each halogen heater 7, 11 is controlled by the temperature controller 12. The temperature control device performs on / off control for the operation of each halogen heater 7, 11 based on the surface temperature of the heating roller 1 detected by the thermistor 12a. The surface temperature of the heating roller 1 and the surface temperature of the pressure roller 2 are maintained at a temperature of 160 ° C., and the interface temperature between the silicon rubber layer 6 and the core metal 5 of the heating roller 1 is maintained at 190 ° C. or less. ..

During fixing, the dimethyl silicone oil 51 applied to the surface of the heating roller 1 and the heating roller 1
The dimethyl silicone oil 51 impregnated in the silicone rubber layer 6 is heated to 190 ° C. by the heating roller 1, but the volatilization amount of the dimethyl silicone oil 51 at the temperature of 190 ° C. is very small, and the low molecular weight of the dimethyl silicone oil 51 is low. The components do not adhere to the primary wire of the primary charger, the reflection mirror, each sliding member (not shown) and the like. Therefore, dimethyl silicone oil 51
The occurrence of linear and band-shaped uneven charging due to the adhesion of the primary charging device to the primary wire is prevented, and linear or band-shaped uneven density does not occur in the formed image.

The reflection mirror is not contaminated due to the adhesion of the low-molecular weight component of the silicone oil to the reflection mirror, and the image exposure failure on the photosensitive drum due to the contamination of the reflection mirror does not occur. Further, the slidability of each sliding member is not impaired by the adhesion of the low molecular weight component to each sliding member.

In this embodiment, it was confirmed that the image unevenness did not occur on 400,000 sheets of paper passing, and it was possible to prevent the image formation failure due to the volatile component of the dimethyl silicone oil 51. You can

Next, another fixing device will be described. FIG. 4 is a block diagram showing still another embodiment of the fixing device of the present invention.

Still another fixing device is, as shown in FIG. 4, a dimethyl silicone oil 5 on the silicone rubber layer 6.
A heat roller 1 impregnated with the heat roller 1, a pressure roller 2 rotated while being pressed against the heat roller 1, and a heat roller 1.
And cleaning means 4 for cleaning.

A halogen heater 7 as a heating source is arranged in the core metal 5 of the heating roller 1, and a core metal 8 of the pressure roller 2 is provided.
A halogen heater 11 is arranged inside.

The operation of each halogen heater 7, 11 is controlled by the temperature controller 12. The temperature control device 12 performs on / off control for the operation of each halogen heater 7, 11 based on the surface temperature of the pressure roller 2 detected by the thermistor 12a. Surface temperature of heating roller 1 and pressure roller 2
The surface temperature of is maintained at 190 ° C. during fixing. The cleaning means 4 has a web 52 impregnated with dimethyl silicone oil 51, and the web 52 is fed from the feeding shaft 4a through the pressing roller 4b toward the winding shaft 4c.

From the above, dimethyl silicone oil 5
Since 1 is impregnated in the web 52, the content of the dimethyl silicone oil 51 is small. Therefore, the dimethyl silicone oil 51 contains no low-molecular component, and the dimethyl silicone oil 51 contained in the web 52 contains It has been confirmed that the volatilization amount of the dimethyl silicone oil 51 is further reduced due to the small content, and a good image can be obtained up to 400,000 sheets.

In this embodiment, the dimethyl silicone oil 51 having a viscosity of 300 cs is used, but a silicone oil having a viscosity of 10,000 cs can be used instead. The concentration of each M2Dn body (n≤18) of this silicone oil having a viscosity of 10,000 cs is 50 p.
Dm body (m ≦ 2) which is less than pm and is a low molecular weight component thereof.
The respective concentrations of 0) are 50 ppm or less. When using this silicone oil with a viscosity of 10,000 cs, 4
It has been confirmed that image formation failure does not occur up to the passage of 0,000 sheets.

Next, the fixing device used in the monochrome image forming apparatus will be described. FIG. 5 is a block diagram showing still another embodiment of the fixing device of the present invention.

As shown in FIG. 5, the fixing device used in the black and white image forming apparatus includes a heating roller 1, a pressure roller 2 which is rotated while being in pressure contact with the heating roller 1, and dimethyl silicone oil on the heating roller 1. A release agent applying unit 3 for applying 51 and a cleaning unit 4 for cleaning the heating roller 1 are provided.

The heating roller 1 has a hollow cored bar 5 made of aluminum, and the outer peripheral surface of the cored bar 5 is covered with a silicone rubber layer 6. The silicone rubber layer 6 is an HTV (high temperature vulcanization type) silicone rubber layer having a thickness of 0.8 mm, and an RT having a thickness of 200 μm formed as an outer layer of the silicone rubber layer.
V (room temperature vulcanizing type) silicone rubber layer, and the thickness dimension of the silicone rubber layer 6 is 1 mm. The thermal conductivity λ of the silicone rubber layer 6 is 1 × 10 ⁻³ cal / sec.cm.deg. The silicone rubber layer 6 is impregnated with dimethyl silicone oil 51.

The pressure roller 2 has a hollow cored bar 8 made of aluminum, and the outer peripheral surface of the cored bar 8 is covered with a silicone rubber layer 9. The silicone rubber layer 9 is an HTV (high temperature vulcanization type) silicone rubber layer having a thickness of 2.0 mm. A fluororesin layer (not shown) is formed on the surface of the silicone rubber layer 9. The pressure roller 2 cooperates with the heating roller 1 to form a nip portion for conveying the transfer material P under pressure.

In the core metal 5 of the heating roller 1, a halogen heater 7 as a heating source is arranged.

The operation of the halogen heater 7 is performed by the temperature controller 1.
Controlled by 2. The temperature control device 12 includes a thermistor 12
On / off control for the operation of the halogen heater 7 is performed based on the surface temperature of the heating roller 1 detected in a. The surface temperature of the heating roller 1 is maintained at 180 ° C. during fixing.

From the above, dimethyl silicone oil 5
The generation of linear and band-shaped charge unevenness due to the adhesion of the primary charger of No. 1 to the primary wire is prevented, and no linear or band-shaped density unevenness occurs in the formed image.

[0098]

As described above, according to the fixing device of the present invention, since the release agent applied to the one rotating body does not volatilize at the surface temperature of the rotating body, the releasing agent is released. Volatile components of the primary charger primary wire, reflective mirror,
Since it does not adhere to each sliding member, etc., the occurrence of linear or band-shaped uneven charging due to the adhesion of the volatile component to the primary wire of the primary charger is prevented, and linear or band-like density unevenness in the image is prevented. Image defects such as occurrence can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a fixing device of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the fixing device of the present invention.

FIG. 3 is a configuration diagram showing still another embodiment of the fixing device of the present invention.

FIG. 4 is a configuration diagram showing still another embodiment of the fixing device of the present invention.

FIG. 5 is a configuration diagram showing still another embodiment of the fixing device of the present invention.

FIG. 6 is a configuration diagram showing a conventional multicolor image forming apparatus.

FIG. 7 is a diagram showing a softened S-shaped curve representing the relationship between the plunger drop amount of color toner and temperature.

8 is a configuration diagram showing a fixing device used in the multicolor image forming apparatus of FIG.

[Explanation of symbols]

 1 Heating Roller 2 Pressure Roller 3 Release Agent Applying Means 4 Cleaning Means 7, 11 Halogen Heater 12 Temperature Controller 12a Thermistor 13 Container 51 Dimethyl Silicone Oil 52 Web

Claims (5)

[Claims] 1. A pair of fixing rotators that rotate while being pressed against each other to form a nip portion for nip-conveying a transfer material, and a release agent that applies a release agent to at least one of the rotators. In a fixing device including a coating means, the unfixed developer image formed on the transfer material at the nip portion is heated and pressed to fix the unfixed developer image on the transfer material as a permanent image. The concentration of each of the low molecular weight M2Dn compounds (n≤18) of the release agent is 50 pp.
Dm body (m not more than m, which is a low molecular component of the release agent)
The fixing device is characterized in that each concentration of ≦ 20) is 50 ppm or less, and the heating temperature in the nip portion is maintained at 200 ° C. or less. 2. The fixing device according to claim 1, wherein the heating temperature for the unfixed developer image on the transfer material at the nip portion is maintained at 190 ° C. or lower. 3. The temperature at the nip portion is 190 during standby.
The fixing device according to claim 1, wherein the fixing device is maintained at a temperature of not more than ° C. 4. A release layer capable of containing the release agent is formed on one of the rotating bodies to which the release agent is applied, and the internal temperature of the release layer is maintained at 190 ° C. or lower. The fixing device according to claim 1. 5. The fixing device according to claim 1, wherein the releasing agent is made of silicone oil.