JPH10221991A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact fixing device being capable of obtaining a full color image of stable glossiness with which a user is relaxed psychologically, but not fatigued even if he or she looks at many copies. SOLUTION: The front layers 13 and 13a of a fixing roller 3 including a heat source and a pressure roller 4 coming into press-contact with the fixing roller 3 are made of fluororesin. It is constituted so that the quotient obtained by dividing the pressing force F [kgf] of the fixing roller 3 and the pressure roller 4 against a recording material 10 by the product L1×L2 [mm<2> ] of the length L1 [mm] in a lateral direction and length L2 [mm<2> ] in a longitudinal direction of a press-contact part as the area of the press-contact part. N of the fixing roller 3 and the pressure roller 4 is <=0.025 [kgf/mm<2> ] and the length L1 in the lateral direction of the press-contact part N is >=8.0 [mm]. Thus, a multi-color and -layer or monochrome unfixed developer image 11 is surely fixed on the recording material 10 carrying the unfixed developer image 11, with low glossiness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device,
In particular, the present invention relates to a color fixing device such as an electrophotographic device.

[0002]

2. Description of the Related Art Conventionally, a fixing roller and a pressure roller are provided, and a recording material carrying a multicolor multi-layer or single-color unfixed developer image is nipped and conveyed at a pressure contact portion between the fixing roller and the pressure roller. There is a fixing device that fixes an unfixed developing material image on a recording material.

FIG. 6 is a schematic sectional view of a heat roller fixing device used as a toner image fixing device in a color image forming apparatus such as an electrophotographic apparatus as an example of such a fixing apparatus. Hereinafter, this heat roller fixing device will be described with reference to the drawings.

In FIG. 1, reference numeral 21 denotes a fixing roller.
A pressure roller 22 that performs a driven rotation while forming a nip N between the fixing roller 21 and the fixing roller 21 is in pressure contact with the fixing roller 21. Here, the fixing roller 21 has a silicon rubber layer on the core of the hollow cylindrical body, and a halogen heater 23 as a heat source is included in the hollow space of the core to supply heat necessary for fixing. It has become. The pressure roller 22 has a silicone rubber layer on a metal core in the form of a hollow cylinder like the fixing roller 21, and is heated by a halogen heater 23 ′ contained in the hollow space of the metal core. ing.

The fixing and pressurizing rollers 21,
In the temperature control of 22, the thermistor 24 serving as a temperature detecting element is disposed in contact with the fixing roller 21 or the pressure roller 22, or the thermistors 24 and 24 'are disposed in contact with both the fixing roller 21 and the pressure roller 22 as shown in FIG. The surface temperature of the rollers 21 and 22 is detected based on a change in resistance value according to the detected temperature, and the halogen heaters 23 and 23 'are turned on by a control device (not shown) so that the roller surface temperature becomes a predetermined value.
This is done by turning off.

An oil application roller 32 is provided in contact with the surface of the fixing roller 21. When the oil application roller 32 rotates, oil is applied from the oil supply unit to the roller surface. It has become. Note that silicone oil is suitable as the oil used.

Here, in the heat roller fixing device having such a configuration, the unfixed recording material is guided by the front guide 28, enters the nip portion N from the right side in the figure, and forms a uniform oil layer. After being pressed and heated by the surface of the roller 21 and fixed, the sheet is guided by a rear guide 28 ′ and discharged. The surface of the fixing roller 21 on which the fixing is performed is again rubbed with the cleaning web 27 during the rotation, so that the offset toner is removed and oil is applied at the same time, while excess oil is peeled off. It has become. Reference numeral 29 denotes a separation claw between the fixed recording material and the pressure roller 22.

In the fixing roller 21, the thickness (multiple to several tens) of the multi-color toner of a single color to four colors of a color image is obtained.
μm), it is necessary to provide an elastic layer of several tens μm or more on a core shaft of aluminum or the like. In addition,
When the elasticity is small, the toner concave portion which is a developer is not fixed, and the resolution is reduced due to the collapse of the toner.

Here, the material of the elastic layer may be a liquid silicone rubber RTV or LTV of methyl type or methyl vinyl type.
It is optimal that the TV type has an elasticity of 20 ° to 25 ° rubber hardness (JISA). In particular, RTV has a high affinity for silicone oil and is easy to apply oil. Furthermore, the above-mentioned RTV, LT
V may be used, and a heat-resistant HTV layer may be provided as a lower layer to prevent thermal degradation and peeling of the back surface of the surface layer to form a multilayer structure.

On the other hand, the pressure roller 22 is
Simplification is possible because the elasticity may be smaller than that of
The aluminum core shaft may be provided with only a layer of HTV, fluoro rubber, or the like, or may be a surface layer coated with PFA or PTFE to prevent oil lubrication. Also, RT
V may be used. Of course, a roller having substantially the same configuration as the fixing roller 21 may be used. In addition, as the rubber of the fixing roller 21 and the pressure roller 22, a methylphenyl-based silicone rubber may be used.

Further, as the oil material, a methylphenyl silicone oil is used, and it is preferable to use a phenyl group content of 5 mol% or more from the viewpoint of preventing swelling. On the other hand, if the viscosity is too low, the swelling property becomes large, and the in-machine contamination due to volatilization also worsens. On the other hand, if the viscosity is too high, the adhesion to the roller deteriorates. In the conventional heat roller fixing device, the fixing temperature is 120 to 1
The ripple is within ± 3 ° within the range of 80 ° C., and the roller peripheral speed is in the range of 100 to 120 mm / sec.

The oil supply section includes an oil tank 38 which is an exchangeable oil container, and an oil pump 3 connected to the oil tank 38 via a joint 37 and a tube (not shown) such as silicone resin.
6 is provided. The oil tank 38 has oil O contained in an aluminum pack in a rigid case. The joint 37 is made of a combination of a rubber seal, a spring, and the like, so that when the oil tank 38 is detached, the oil seals from both are made.

On the other hand, the oil pump 36 serves to send oil to the oil supply nozzle 33 in the application section. It is preferable that the type of the pump employs a system in which the amount of oil is controlled by a pulse signal using an electromagnetic pump. Also, the use of a gear pump may be inexpensive. The pump may be provided with a check valve. Since the oil supply unit is a completely closed system and has no fear of leakage, it can be provided on the apparatus main body side or on the fixing unit side.

In the oil application section, the oil sent from the oil supply nozzle 33 is closely or extremely close to the oil application roller 32 having silicone rubber as a surface layer, and is used for holding a small amount of the supplied oil. After the oil is supplied by the plate 34, the oil is held between the plate 34 and the oil application roller 32 only for a short period of time.

Thereafter, the amount of oil is regulated by the oil application blade 31 with the rotation of the oil application roller 32, and a uniform thin layer application is performed on the oil application roller 32. The surplus oil is supplied to the plate 34 for oil.
Then, the oil falls along the bottom of the oil case 35, is collected again by the oil pump 36, and is reused.

On the other hand, the oil applied to the fixing roller 21 by the oil applying roller 32 is absorbed or adhered to the sheet and goes out of the apparatus as the sheet passes.
The oil applied during the non-sheet passing portion or during the forward / backward rotation of the first roller adheres to and transfers to the pressing roller 22, and is then cleaned by the cleaning blade 25 together with the paper powder and toner.
2 and then the cleaning blade 25
It falls down and is promptly absorbed by the oil absorber 30 in the oil pan 26 which is a waste oil recovery container.

The material of the cleaning blade 25 is preferably a material such as fluororubber which is excellent in releasability and non-wearing sliding property. The material of the oil absorber 30 is preferably a material that absorbs oil mainly by a capillary action of a natural or natural woven or porous body. For example, several to several tens of μm of polyester, polypropylene, polyethylene, etc.
A nonwoven fabric processed by laminating fibers having a diameter of several cm or less is preferred. Further, the surface may be subjected to a treatment for increasing lipophilicity. In addition, a method of solidifying the oil by a chemical change is also conceivable. Note that the oil pan 26 containing the oil absorber 30 is detachable and replaceable from the fixing unit.

By the way, a sharp-melt non-mag toner having a low softening point and a low melt viscosity is used as a toner in order to enhance the color mixing property. High-temperature offset to the roller 21 is likely to occur. Here, in order to prevent this high-temperature offset, silicone oil is required as a release agent for improving the release property, but when such a release agent is used, user maintenance is complicated. At the same time, there was a risk of oil leakage during transportation and transportation, and the tentacle feeling of OHT (overhead transparency) was deteriorated. Conversely, a toner having a high melt viscosity does not require oil, but has low color mixing properties, resulting in poor picture image clarity and poor light transmission of OHT.
Only a dark OHT projection image was obtained.

On the other hand, in order to achieve oillessness, a sharp-melt toner is prepared by adding a releasing agent such as wax or paraffin having a lower melting viscosity and molecular weight smaller than that of the base resin of the toner as a releasing agent to a toner by a polymerization method. PFA or FE on the surface layer of the fixing roller 21 and the pressure roller 22
By providing a release layer such as P, it is also possible to achieve oilless operation in a configuration in which the release effect of the heat roller fixing device is enhanced.

However, in the fixing device having such a configuration, by providing a release layer such as PFA or FEP, the product hardness of the fixing roller 21 and the pressure roller 22 is reduced to 80%.
° to 90 ° (Asker C) and become hard. In order to secure the fixing property in that state, it is necessary to apply more sufficient heat and pressure.

[0021]

By the way, in such a conventional fixing device, the glossiness of the image area becomes unnecessarily high even when any transfer paper is used.
Even an image formed on a low-gloss transfer paper has high glossiness, which increases the difference in glossiness between the non-image area and the image area, giving the viewer a sense of discomfort. In particular, in the case of a copy image of a monochrome character image for business use, the character itself has high gloss, and therefore, there has been a problem that the character is difficult to read due to reflection.

In order to solve such a problem, the viscoelasticity of the black toner at the time of melting is designed to be higher than that of the color toner, as disclosed in Japanese Patent Application Laid-Open No. 63-300254. Accordingly, means have been proposed in which the glossiness of a monochrome image (that is, a character image) is reduced, and the color image has high glossiness. However, in this method, since the fixing performance of the black toner and the fixing performance of the color toner are greatly different, the fixing conditions for satisfactorily fixing both toners are in a very narrow range,
Other problems such as offset and insufficient fixing strength occur.

As another means, for example, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 204670 discloses a means for fixing a transparent toner over the entire surface of an image to achieve uniform gloss and control. However, this method consumes an enormous amount of transparent toner, and causes other problems such as an increase in complexity of the apparatus due to the additional development step of the transparent toner and a decrease in printer productivity, and is not practical.

On the other hand, it is conventionally considered that the gloss of black is low and the gloss of color is preferably high. But,
In the related art, no upper limit is set for the glossiness of a color. However, when a color printer is used, if the glossiness of a color is too high, the image quality is rather poor psychologically. Therefore, in order to satisfy the fixing property while suppressing the gloss, the fixing device tends to be large. However, in consideration of user friendliness, the device needs to be as small as possible.

Therefore, the present invention has been made in view of such a problem, and provides a user with psychological comfort, does not feel fatigue even when viewing a large number of sheets, and provides a full-color image with stable glossiness. It is an object of the present invention to provide a compact fixing device that can be obtained.

[0026]

According to the present invention, there is provided a fixing roller including a heat source, a pressure roller for pressing against the fixing roller, and a multicolor multi-layer at a pressing portion of the fixing roller and the pressing roller. Alternatively, in a fixing device configured to fix the unfixed developer image on the recording material by nipping and conveying a recording material carrying a single-color unfixed developer image, the surface layers of the fixing roller and the pressure roller may be fixed. A pressing force F applied to the recording material during the nipping and conveying of the fixing roller and the pressure roller, which is formed of a fluororesin.
[Kgf] is a product L1 × L2 [mm] of the length L1 [mm] of the short-side direction and the length L2 [mm] of the long-side direction of the pressing portion, which is the area of the pressing portion of the fixing roller and the pressing roller. ² ]
Is less than or equal to 0.025 [kgf / mm ² ], and the length L1 in the short direction of the press contact portion is 8.0 [m
m] or more.

Further, the present invention is characterized in that the surface layers of the fixing roller and the pressure roller are formed of a fluorine resin tube.

Further, the present invention is characterized in that the hardness of the fixing roller is about 60 ° or less with Asker C.

Further, the present invention is characterized in that at least one surface layer of the fixing roller or the pressure roller is made of a fluorine resin coat.

The present invention is also characterized in that the hardness of the fixing roller is about 65 ° or less in Asker C.

Further, as in the present invention, the surface layer of the fixing roller containing the heat source and the pressure roller which is in pressure contact with the fixing roller are formed of a fluorine resin, and the pressing force F of the fixing roller and the pressing roller against the recording material is used. [Kgf] is the length L1 [mm] of the pressing portion, which is the area of the pressing portion of the fixing roller and the pressing roller, and the length L2 [mm] of the pressing direction.
The quotient divided by the product of L1 × L2 [mm ² ] is 0.025
[Kgf / mm ² ] or less and the short-side length L1 of the press-contact portion is 8.0 [mm] or more, so that a multicolor multi-layer or single-color unfixed developer image is carried. An unfixed developer image is reliably fixed on the recording material with a low glossiness.

[0032]

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

FIG. 1 is a diagram showing a configuration of a fixing device according to a first embodiment of the present invention. In the figure, 3 is a fixing roller, 1 is a core metal such as aluminum of the fixing roller 3,
5 is a heater and 9 is a guide. Reference numeral 2 denotes an elastic layer which is a base layer formed on the surface of the cored bar 1. The elastic layer 2 has a thickness of several tens μm or more in order to follow the thickness (several to several tens of μm) of a single color to four-color multiplex toner of a color image. have. In the case where the elastic layer 2 has low elasticity, unfixed toner concave portions and reduced resolution due to crushing of the toner are caused. Therefore, the material of the elastic layer 2 is a methyl-based or methyl vinyl-based liquid silicone rubber. RTV and LTV types have a predetermined elasticity and are suitable.

A release layer 13, which is a surface layer formed on the elastic layer 2, is formed by using the above-mentioned RTV, LTV and the like. By providing the release layer 13 using RTV, LTV, or the like on the elastic layer 2 as described above, thermal deterioration and peeling of the elastic layer 2 can be prevented. Further, when the fixing roller 3 has elasticity, the surface of the fixing roller 3 itself deforms and presses against unevenness of the surface of the unfixed toner image, so that uniform heating and pressing of the toner image can be performed. It is effective for making the gloss uniform.

In this embodiment, as the fixing roller 3, an LTV type of dimethyl silicone rubber (rubber material hardness: JIS-A) is provided on the aluminum cored bar 1.
The elastic layer 2 is formed with a layer thickness of 2.0 mm with a test piece hardness of about 0 ° to 30 °), and the release layer 13 is formed thereon with a PFA tube with a layer thickness of 50 μm. And roller hardness (hardness when the total weight of an Asker C hardness tester manufactured by Kobunshi Keiki Co., Ltd. is 1 kg; hereinafter abbreviated).
The rubber material was appropriately selected so as to be 0 °, 60 °, and 70 °, and was molded to φ40 mm. Note that a methylphenyl-based silicone rubber may be used for forming the fixing roller 3.

On the other hand, 4 is a pressure roller, 1a is a metal core such as aluminum, and 2a is an elastic layer provided on the metal core 1a. Here, the elastic layer 2a can be simplified since the elastic layer 2a of the fixing roller 3 may be smaller in elasticity than the elastic layer 2, and is formed by, for example, providing an HTV, a fluorine rubber, or the like on the aluminum core 1a. It is a thing. Of course, a roller having substantially the same configuration as the fixing roller 3 may be used.

In this embodiment, an LTV type dimethyl silicone rubber (rubber material hardness: about 1 ° to 30 ° in JIS-A test piece hardness) is formed on the aluminum core 1a as the pressure roller 4. ) At elastic layer 2
Is formed with a layer thickness of 1.5 mm, and a release layer 13a is formed thereon with a layer thickness of 50 μm using a PFA tube, and a rubber material is formed so that the roller hardness becomes 55 °, 65 °, and 75 °. It was appropriately selected and formed into φ40 mm. It should be noted that a methyl phenyl silicone rubber can be used for forming the pressure roller 4.

In FIG. 1, reference numeral 11 denotes a polymerized toner which is a developer image to be described later, reference numeral 10 denotes a multicolor multi-layer or single-color unfixed developer image, and a pressing portion between the fixing roller 3 and the pressure roller 4. The transfer paper 15, which is a recording material on which an unfixed developer image is fixed by being nipped and conveyed in the nip portion N, is a heat source of the fixing roller 3. In this apparatus, the fixing temperature was 180 ° C. and the ripple was within ± 3 ° C., and the roller peripheral speed was in the range of 110 to 120 mm / sec. The fixing device used was of A4 size.

An object of the present invention is to reduce the glossiness of each color as described above. here,
The definition of glossiness used in the present invention is based on Method 2 of JISZ8741 applied mainly when measuring the specular glossiness of paper (hereinafter simply referred to as glossiness).

FIG. 2 is a conceptual diagram of a measuring device for measuring the glossiness. In order to measure the glossiness, first, a light source 70 irradiates a sample 72 with light through an optical system 71, and
The reflected light of the sample 72 is transmitted through an optical system 73 to a light receiver 74.
To receive light. Note that, in the figure, S ₁ , S ₁ ′, S
₂ is a slit, α1 is an opening angle of an optical image, β1 is an opening angle in a vertical plane, α2 is an opening angle of a light receiver, and β2 is an opening angle in a vertical plane.

Assuming that the specular reflected light flux from the surface of the sample 72 is φ and the reflected light flux from the standard surface is φS with respect to the designated incident angle θ shown in FIG. Is done.

G = (φ / φS) × (glossiness of used standard surface) Here, the glossiness of the used standard surface is 100.0.
Therefore, the glossiness is represented by a numerical value of 100 or less.

The gloss measuring device used in the present invention is:
Nippon Denshoku Industries Co., Ltd. PG-3D (incident angle θ = 75 °) was used, and the standard surface was black glass having a glossiness of 96.9. As a measuring method, 3.0 mm × 4024 paper (75 g paper, Letter size) manufactured by Xerox Corporation was used.
Nine solid patch images of 3.0mm size are output,
The average value was adopted.

Incidentally, since the glossiness of the image portion is a manifestation of the fixed state of the toner image formed on the image support,
The glossiness can vary depending on the viscoelastic properties of the toner, the mechanical configuration of the fixing process, fixing conditions, and the like.

Therefore, the toner 1 used in the present invention
As No. 1, a toner prepared by a polymerization method in which wax, paraffin, or the like having a melt viscosity and a molecular weight smaller than that of the toner base resin was previously added as a release agent to a sharp melt toner was used. As a result, high color mixing is achieved, and at the time of fixing, the wax oozes out of the toner due to heat, so that the heat roller fixing device achieves an oil-less configuration in which the releasing effect is enhanced.

Next, FIG. 3 shows a schematic configuration diagram of the polymerized toner.

In the figure, reference numeral 11a denotes a core of the polymer toner 11 containing an ester wax, 11b denotes a resin layer formed of styrene-butyl acrylate, and 11c denotes a release layer formed of styrene-polyester. .
Here, the specific gravity of the polymerized toner 11 including the core 11a, the resin layer 11b, and the release layer 11c is about 1.05.

The reason why the polymer toner 11 has a three-layer structure is that the core 11a contains a wax so that an offset preventing effect in the fixing step can be obtained, and the resin layer 11b is formed on the release layer 11c. This is because the charging efficiency is improved by providing the layer. When actually used, silica treated with oil is externally added for stabilizing the tribo.

On the other hand, as a method for producing such a toner, a resin, a release agent comprising a low softening point substance (wax), a colorant, a charge control agent, and the like are charged with a pressure kneader, an extruder, or a media disperser. After uniformly dispersing the particles, the particles collide with a target mechanically or under a jet stream to pulverize the toner to a desired particle size, and then, through a classification process, sharpen the particle size distribution to form a toner. There is a method for producing a toner by the method.

A method for obtaining a spherical toner by atomizing a molten mixture into the air using a disk or multi-fluid noise as described in JP-B-56-13945, etc.
No. 10231, JP-A-59-53856 and JP-A-59-61842, in which a toner is directly produced using a suspension polymerization method, or a method in which a toner is soluble in a monomer. The toner can be produced by an emulsion polymerization method typified by a soap-free polymerization method for directly producing a toner using an aqueous organic solvent in which the obtained polymer is insoluble.

In the present embodiment, a suspension polymerization method under normal pressure or under pressure is used, in which a fine particle toner having a sharp particle size distribution and a particle size of 4 to 8 μm can be obtained relatively easily. And a salicylic acid metal compound as an n-butyl acrylate charge control agent, a saturated polyester as a polar resin, and a colorant were added to produce colored suspension particles having a weight average particle diameter of 7 μm.

Further, the toner particle size distribution and the particle size can be controlled by changing the type or amount of the hardly water-soluble inorganic salt or dispersant having a protective colloid action, or by changing mechanical device conditions such as the peripheral speed of the roller. The toner according to the exemplary embodiment can be obtained by controlling the stirring conditions such as the number of passes and the shape of the stirring blade, the shape of the container, and the concentration of the solid content in the aqueous solution.

As the binder resin used for the toner, generally used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers can be used. Then, in a method of directly obtaining a toner by a polymerization method, those monomers are preferably used. Specifically, styrene, o (m-, p-)-methylstyrene, m (p-)-
Styrene monomers such as ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth)
Octyl acrylate, dodecyl (meth) acrylate,
(Meth) acrylate-based monomer such as stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate Ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide are preferably used.

Here, these can be used alone or generally in the published Polymer Handbook, 2nd edition III-P139-
The monomers are appropriately mixed and used so that the theoretical glass temperature (Tg) described in No. 122 (manufactured by John Wiley & Sons) indicates 40 to 75 ° C. If the theoretical glass transition temperature is less than 40 ° C., problems arise in terms of the storage stability of the toner and the durability stability of the developer. On the other hand, if it exceeds 75 ° C., the fixing temperature rises. In the case of toner, the color mixture of each color toner is insufficient and the color reproducibility is poor, and furthermore, the transparency of the trappen image is remarkably reduced, which is not preferable from the viewpoint of high image quality.

The molecular weight of the binder resin is measured by GPC (gel permeation chromatography). As a specific GPC measurement method, the toner is previously extracted with a toluene solvent using a Soxhlet extractor for 20 hours, and then toluene is distilled off with a rotary evaporator. Further, the ester wax is dissolved, but the binder resin is dissolved. An organic solvent that cannot be dissolved, such as chloroform, was added thereto, and the mixture was sufficiently washed. A solution obtained by filtering a solution dissolved in THF (tetrahydrofuran) through a solvent-resistant membrane filter having a pore diameter of 0.3 μm was used to obtain a sample manufactured by Waters Corporation.
50C and column composition was A-801, 8 manufactured by Showa Denko
02, 803, 804, 805, 806, and 807, and the molecular weight distribution can be measured using a standard polystyrene resin calibration curve.

Here, the number average molecular weight (Mn) of the obtained resin component is 5,000 to 1,000,000, and the ratio (Mw) between the weight average molecular weight (Mw) and the number average molecular weight (Mn).
(w / Mn) is preferably 2 to 100 in the present embodiment. Further, the molecular weight of the wax is smaller than the molecular weight of the binder resin, and the number average molecular weight (Mn) is 1,000 to tens of thousands.

On the other hand, as the colorant used in the toner, carbon black, a magnetic substance, and a black-colored colorant using a yellow / magenta / cyan colorant shown below are used.

Here, as the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds are used. Specifically, C.I.
I. Pigment Yellow 12, 13, 14, 15, 1
7, 62, 74, 83, 93, 94, 95, 97, 10
9, 110, 111, 120, 127, 128, 12
9, 147, 168, 174, 176, 180, 18
1, 191 and the like are preferably used.

Examples of the magenta coloring agent include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. In particular,
C. I. Pigment Red 2, 3, 5, 6, 7, 23,
48: 2, 48: 3, 48: 4, 57: 1, 81: 1,
144, 146, 166, 169, 177, 184, 1
85, 202, 220, 221, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15:
1, 15: 2, 15: 3, 15: 4, 60, 62, 66
Etc. can be used particularly preferably.

These colorants can be used alone or in a mixed color, or in the form of a solid solution. The colorant of the present embodiment is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, trapene permeability, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the resin. When a magnetic material is used as a black colorant, it is used by adding 40 to 150 parts by weight to 100 parts by weight of the resin, unlike other colorants.

Next, in the fixing device of this embodiment,
When the fixing roller hardness is 50 ° (Asker C) and the pressing roller hardness is 55 ° (Asker C), the fixing property and glossiness when the pressing force [kfg] is changed, and the fixing roller 3 shown in FIG. The length L1 [mm] and the pressing force / (L) of the nip portion N, which is a pressing portion formed by the
1 × L2) [kfg / mm ² ] is shown in Table 1. Here, L2 is the length in the longitudinal direction of the nip portion N shown in FIG.
Is 310 mm. L1 × L2 represents the area of the nip portion N.

[0063]

[Table 1] From the results shown in Table 1, when the fixing roller hardness is 50 ° and the pressure roller hardness is 55 °, the pressing force when satisfying the low glossiness (25% or less) and the fixing property (△ or more) is 20.
It can be seen that it is [kgf] to 70 [kgf].

Next, when the hardness of the fixing roller is 60 ° and the hardness of the pressure roller is 65 °, the fixing property, the glossiness, and the length of the nip portion N in the short direction when the pressing force [kgf] is changed. L
1 [mm], pressure / (L1 × L2) [kfg / mm
² ] is shown in Table 2.

[0065]

[Table 2] From the results in Table 2, when the fixing roller hardness is 60 ° and the pressure roller hardness is 65 °, the pressing force when satisfying the low glossiness (25% or less) and the fixing property (△ or more) is 25.
It turns out that it is [kgf] -50 [kgf].

Next, in the fixing device of this embodiment, when the fixing roller hardness is 70 ° and the pressing roller hardness is 75 °, the fixing property, the glossiness, and the nip portion when the pressing force [kgf] is changed. The length L1 in the short direction of N [mm], the pressing force / (L1 ×
Table 3 shows the relationship of L2) [kfg / mm ² ].

[0067]

[Table 3] From the results shown in Table 3, when the fixing roller hardness is 70 ° and the pressing roller hardness is 75 °, the pressing force that satisfies the low glossiness (25% or less) and the fixing property (△ or more) is 45 k.
gf.

Further, from the results of Tables 1, 2 and 3,
In order to satisfy the low glossiness, it is necessary to reduce the pressing force of the nip N, and in order to satisfy the fixing property,
The length L1 [mm] of the nip portion N in the short direction is 8 [m].
m] or more.

From the above, it is possible to satisfy the fixing property and the low glossiness by simultaneously satisfying the following two expressions. Nip pressure = Pressure / (L1 × L2) [kgf
/ Mm ² ] ≦ 0.025 Length L1 [mm] ≧ 8.0 in the lateral direction of the nip portion N When the fixing roller hardness is larger than 70 ° and the pressure roller hardness is larger than 75 °, , L1 = 8, the pressing force / (L1 × L2)> 0.025, and if the pressing force / (L1 × L2) = 0.025, L1 <8. In the case of (1), the fixability is good, but the glossiness is increased. In the above case, the fixing property is satisfied even though the nip is smaller than 8.0 [mm]. However, since the roller hardness is high, the pressure applied to the nip surface is large and the fixing property is good. This is because the glossiness is also increased.

By satisfying the above two expressions at the same time, even if the fixing device is small, uniform fixing can be ensured even in a full-color image and a mono-color image while securing the fixing property. It is possible to obtain a low gloss level, thereby reducing the difference in gloss level between the non-image area and the image area, and preventing a problem that characters are difficult to read due to high gloss reflection.

Next, a second embodiment of the present invention will be described.

In the present embodiment, at least one surface layer of the fixing roller or the pressure roller of the fixing device shown in the first embodiment described above has a coat softer than the tube.

That is, in the present embodiment, as shown in FIG. 5, as the fixing roller 3, an LTV type elastic layer 2 of dimethyl silicone rubber is formed on the aluminum cored bar 1 to a thickness of 2.0 mm. An intermediate layer 14 is formed thereon with a thickness of 50 μm using a fluoro rubber, and a P layer is further formed thereon.
A release layer 13 as a surface layer having a thickness of 15 μm formed by FA coating (fluororesin coating) was formed into φ40 mm. In addition, a methylphenyl silicone rubber can also be used.

Further, as the pressure roller 4, an LTV type elastic layer 2a of dimethyl silicone rubber is provided on the aluminum core metal 1a by 1.5 mm, and an intermediate layer 14a of 50 μm is provided thereon by a fluoro rubber, and further thereon. A PFA coat 13a having a thickness of 15 m was formed as a high release coating layer to a diameter of 40 mm. In addition, as the rubber of the fixing roller 3 and the pressure roller 4, a methylphenyl silicone rubber may be used. In this apparatus, the fixing temperature was 180 ° C. and the ripple was within ± 3 ° C., and the roller peripheral speed was in the range of 110 to 120 mm / sec. The fixing device used was of A4 size.

Next, in the fixing device according to the present embodiment in which the surface layer of the roller is changed from a tube to a coat, when the fixing roller hardness is 60 ° and the pressing roller hardness is 65 °, that is, the roller hardness is When the same as in the first embodiment, the fixing property, the glossiness, the length L1 [mm] of the nip portion N in the short direction when the pressing force [kgf] is changed, the pressing force / (L1 × L2) ) [Kfg / mm ² ] is shown in Table 4.

[0076]

[Table 4] From the results shown in Table 4, when the fixing roller hardness is 60 ° and the pressing roller hardness is 65 °, the pressing force for satisfying the low glossiness (25% or less) and the fixing property (△ or more) is 20.
[Kgf] to 60 [kgf], and since the surface layer of the roller is changed from a tube to a coat, the roller can be used with a higher roller hardness than the tube roller shown in Table 2, and a wider pressure latitude can be taken. I can do it.

The fixing roller hardness for simultaneously satisfying the low glossiness and the fixing property is about 60 ° or less (Asker-C) as a result of detailed examination of the tube surface layer system of the first embodiment. On the other hand, in the coating system of the present embodiment, it was approximately 65 ° or less.

Therefore, by forming the surface layers 13, 13a of the rollers 3, 4 from a tube as in the present embodiment, a fixing device having a lower glossiness and a higher fixing property can be provided. In addition, as a coat material,
In addition to PFA, FEP, PTFE, etc. can be used,
Further, the fluorine rubber layer of the intermediate layer may be omitted.

Next, a third embodiment of the present invention will be described.

In this embodiment, while the surface layer of the roller of the fixing device shown in the first embodiment is made a coat softer than the tube, the rubber hardness of the roller is increased by that amount, and the low gloss Pressure and / or
(L1 × L2) [kgf / mm ² ] ≦ 0.025, and the condition of the length L1 [mm] of the nip portion N in the short direction ≧ 8.0 is satisfied. The fixing device is the same as that of the second embodiment, and the description is omitted.

In this embodiment, the roller hardness is 50 °
The case of (Asker-C) was examined. When the roller hardness is 50 °, when the surface layer of the roller (see FIG. 1) is a tube, when the base layer rubber hardness (JISA standard) is 1 ° rubber, but when the surface layer of the roller is coated (see FIG. 5) In addition, the base rubber hardness (JISA standard) for realizing the same roller hardness of 50 ° could be increased to 3 °.

Next, in a fixing device having a roller having such a configuration, when the fixing roller hardness is 50 ° and the pressing roller hardness is 55 °, the fixing property when the pressing force [kgf] is changed, Gloss degree, length L1 [m in short direction of nip N
Table 5 shows the relationship between [m] and the pressing force / (L1 × L2) [kfg / mm ² ].

[0083]

[Table 5] From the results in Table 5, when the fixing roller hardness is 50 ° and the pressing roller hardness is 55 °, the pressing force when satisfying the low glossiness (25% or less) and satisfying the fixing property (△ or more) is as follows. 1
It was found to be 20 [kgf] to 70 [kgf] as in the case of (1).

Therefore, similarly to the first embodiment,
Pressure / (L1 × L2) [kgf / mm ² ] ≦ 0.02
5, the length L1 [mm] of the nip portion N in the lateral direction ≧ 8.
0, low gloss (25% or less), fixability (△ or more)
Are satisfied.

Further, when a fixing device having a surface layer of a roller and a base rubber of 1 ° is used during the paper-passing durability, 5,000 wrinkles and cracks are generated in the roller,
Roller rubber rupture occurred on 10,000 sheets because the roller surface was coated and the base rubber was 3 rubber as in this embodiment.
When using a fixing device of °, the wrinkles and cracks of the roller and the rubber breakage of the roller do not occur even with 50,000 sheets. Was.

As described above, by changing the surface layer of the roller of the fixing device from a tube to a soft coat, the roller hardness of the base layer rubber can be increased accordingly. By increasing the strength of the rubber in this way, it is possible to prevent the roller from being broken or the roller from being damaged such as roller wrinkles and roller cracks, and to increase the durability of the fixing device.

[0087]

As described above, according to the present invention, the quotient obtained by dividing the pressing force F [kgf] by the area of the pressure contact portion is 0.02.
By ensuring that the width is 5 kgf / mm ² or less and that the length of the press-contact portion in the width direction is 8.0 mm or more, even a small fixing device has a uniform low glossiness. Can be obtained, the difference in glossiness between the non-image area and the image area can be reduced, and the fixability can be ensured. As a result, it is possible to provide a small-sized fixing device that psychologically provides the user with comfort, does not feel tired even when viewing a large number of sheets, and can obtain a full-color image with stable glossiness.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a fixing device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a gloss measuring device used for measuring gloss in the present invention.

FIG. 3 is a schematic sectional view of a polymerization toner used in the fixing device.

FIG. 4 is a plan view showing a pressure contact portion formed by a fixing roller and a pressure roller of the fixing device.

FIG. 5 is a diagram illustrating a schematic configuration of a fixing device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a schematic configuration of a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Core metal 2, 2a Elastic layer 3 Fixing roller 4 Pressure roller 10 Transfer paper 11 Polymerized toner 13, 13a Release layer 14, 14a Intermediate layer

Claims (5)

[Claims] A fixing roller including a heat source; and a pressure roller for pressing against the fixing roller, and a multicolor multi-layer or single-color unfixed developer image at a pressure contact portion between the fixing roller and the pressure roller. A fixing device configured to fix the unfixed developer image on the recording material by nipping and conveying the recording material carrying the fixing material, wherein the surface layers of the fixing roller and the pressure roller are formed of a fluorine-based resin. A pressing force F [kg] on the recording material during the nipping and conveying of the fixing roller and the pressure roller.
f] is the product L1 × L2 [mm ² ] of the length L1 [mm] in the width direction and the length L2 [mm] in the lengthwise direction of the pressing portion, which is the area of the pressing portion of the fixing roller and the pressing roller. Quotient divided by 0.025 [kgf / mm ² ] or less, and the length L1 in the short direction of the press-contact portion is 8.0 [mm] or more. Fixing device. 2. The fixing device according to claim 1, wherein the surface layers of the fixing roller and the pressure roller are formed of a fluorine resin tube. 3. The fixing device according to claim 1, wherein the hardness of the fixing roller is about 60 ° or less with Asker C. 4. The fixing device according to claim 1, wherein a surface layer of at least one of the fixing roller and the pressure roller is coated with a fluorine-based resin. 5. The fixing device according to claim 4, wherein the hardness of the fixing roller is about 65 ° or less in Asker C.