JPH11219057A - Full-color toner fixing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a full-color toner image of median gloss (reflectance of 10 to 40%) in which color toners, cyan, magenta, yellow, and black, are sufficiently mixed and no offset phenomena are exhibited. SOLUTION: The glossiness of a full-color fixed image at a normal fixing temperature of -10 to +10 deg.C is set to 10 to 40% and its surface roughness Rz is set smaller than 10 μm, thereby obtaining a full-color image having high color development and no offset. It is preferable that the toner used here have, as its main constituents, coloring agent, binding resin, and releasing agent which is not compatible with the binding resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner fixing method for obtaining a full-color image by using yellow, magenta, cyan, and black toners by electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art In general, in an electrophotographic method, an electric latent image is formed on a photoreceptor, the latent image is developed using toner, and, if necessary, a toner image is transferred onto paper or the like. Alternatively, it is fixed by a solvent vapor or the like to obtain a copy. As a method for visualizing an electric latent image with toner, a magnetic brush method, a cascade developing method, a powder cloud method, and the like are known, but in any of the developing methods, the subsequent fixing of the toner image is an important step. Needless to say, there is. In particular, in the case of using a heat roller fixing device, the so-called offset phenomenon in which a part of the toner image adheres to the heat roller surface and transfers is required because the heat roller comes in contact with the toner image in a heat-fused state during fixing. Is done.

Conventionally, to prevent offset, the surface of the fixing roller has been coated with a thin film of a highly releasable liquid such as silicone oil or fluorine oil, or a toner such as low molecular weight polyethylene or low molecular weight polypropylene has been incorporated into toner particles. A method of adding a mold agent has been proposed. In the case of black toner for black and white printing, the toner is melted by heat,
If there is no offset by the above method,
A sufficient fixed image can be obtained. On the other hand, in the fixed image of the full-color toner, the toners of the respective colors are superimposed, and they are fused and mixed to form a clear color image. For this purpose, the full-color toner needs to have low viscosity. is there. However, full-color toners have the disadvantage that offsets are more likely to occur when the viscosity is reduced, and there is a trade-off between clear coloring and the occurrence of offsets. Various methods have been proposed to break this trade-off relationship.

[0004] For example, in the binder resin of toner, Japanese Patent Application Laid-Open Nos. 1-234863 and 1-221758,
Examples thereof include those in which the molecular weight distribution is specified as in JP-A-3-294863 and those in which a styrene acrylic resin and a polyester resin are combined as in JP-A-2-161664. On the other hand, the low viscosity required for a full-color toner is not only for sufficient color mixing, but also for obtaining high gloss. The use of a heat-fixing roller can provide a gloss over a wide range of 2 to 60%, but recently gloss that is too high may be disliked, and the appropriate gloss tends to be lower than before. However, setting the medium gloss level to an appropriate gloss level causes various problems. That is, the value of the glossiness is most likely to change in a general full-color toner. Also, unlike the case of high gloss, the surface state of the image can be various states,
A glossy image alone cannot be said to be a sufficient fixed image.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a medium gloss fixed image in which toners of respective colors are sufficiently mixed and no offset occurs, and a method of forming such a fixed image.

[0006]

In order to obtain a good medium gloss image in the present invention, (1) in a heating roller fixing method, the fixing roller is a soft roller made of an elastic material and has a standard fixing temperature of -10 ° C. In a full-color toner fixing method, wherein the fixed image has a glossiness of 10 to 40% and a surface roughness Rz of less than 10 μm when fixed at a temperature in the range of + 10 ° C. The roller is a soft roller made of an elastic body coated with release oil, and has a standard fixing temperature of -10 ° C to +
The glossiness of the fixed image at the time of fixing in the range of 10 ° C. is 10
-40%, surface roughness Rz is smaller than 10 μm, Rma
In the full-color toner fixing method, wherein x-Rz does not exceed 10 μm, and (3) in the heating roller fixing method, the fixing roller is a soft roller made of an elastic material to which no release oil is applied, and has a standard fixing temperature of − 10 ℃
When the fixed image is fixed in the range of + 10 ° C., the glossiness of the fixed image is 10 to 40%, the surface roughness Rz is smaller than 10 μm, and R
A full-color toner fixing system characterized in that max-Rz does not exceed 8 μm is proposed.

In the fixing methods (1), (2) and (3), (4) fixing is performed using a toner containing at least a colorant, a resin, and a release agent incompatible with the resin. (5) weight average molecular weight of 15,000 to 4
(6) fixing using a toner containing a non-linear resin, and fixing using a toner containing a resin component having a molecular weight of 100,000 or more.
And / or (7) fixing to paper or film having a surface roughness Rz of 35 μm or less.

[0008] The "standard fixing temperature" in the present invention is a set temperature of a fixing device in normal use. According to the method of the present invention, by setting the fixing temperature of a full-color image to a certain range, setting the glossiness of the obtained image to 10 to 40%, and reducing the surface roughness Rz of the image to less than 10 μm, the coloring property is improved. A high-quality full-color image without high offset is obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Standard fixing temperature in the present invention -10 ° C to +10
The glossiness of the fixed image at 10 ° C. is preferably 10 to 40%, and the surface roughness Rz (10-point average roughness) of the fixed image is preferably smaller than 10 μm. Generally, the glossiness of a fixed image increases as the fixing temperature increases. However, depending on the characteristics of the toner, the gloss may not only continue to rise, but also begin to decrease after a certain temperature. This decrease is considered to be due to the fact that the toner is sufficiently melted, the cohesive force between the toners is weakened, and the toner is transferred to the fixing roller side.
The phenomenon that the toner transferred to the roller side is fixed on the paper is the offset. In fact, even if no offset has occurred, it is likely to transfer to the fixing roller side,
The image surface rises, and the gloss decreases. When it further rises and moves to the fixing roller side, an offset occurs. Therefore, the fixed image preferably has a surface roughness Rz not exceeding 10 μm.

Further, when the release oil is applied to the fixing roller, the toner may return to the toner layer side even if the toner is likely to transfer or even rises due to the effect of the release oil. In this case, the surface becomes rough. On the other hand, even if the toner is transferred, the toner adheres to an oil application pad or the like, and is not fixed on paper. In this case, the toner is transferred even if the offset phenomenon does not occur on the fixing paper. In such a case, the swell may be partially large. The surface roughness Rmax (highest peak) of the fixed image is significantly different from the value of Rz. Therefore, Rmax
It is preferred that the value of -Rz does not exceed 10. If it exceeds 10, transfer to the fixing roller side may occur. If such a state continues, there is a possibility that effective oil application cannot be performed.

Further, when oil is not applied to the fixing roller, the toner is likely to be transferred without the effect of the release oil. Further, even when a small amount of toner is transferred, there is no such thing as wiping the toner such as an oil application pad. Therefore, it is preferable that the value of Rmax-Rz does not exceed 8. Although it is not clear when it exceeds 8,
The fixing paper may be slightly offset.

Also, in an image having a peak in the gloss change, there are two types of fixing surfaces before and after reaching the peak even if the gloss is the same. Even if the glossiness is the same, there is a difference in the margin before the occurrence of the offset before and after the peak. Therefore, the surface roughness Rz of the fixed image
Is smaller than 10 μm, it is possible to obtain an image having a sufficient offset.

On the other hand, in the case of a medium gloss image (gloss level of 10 to 40%), not only the image immediately before the offset but also the case where the melting of the toner is insufficient is considered. In this case, since the toner is present in the form of particles, the surface is not smooth, and if the melting is insufficient, high color developability cannot be obtained. Therefore, by making the surface roughness Rz of the fixed image smaller than 10 μm, it is also possible to obtain a high color image. Note that the surface roughness Rz and Rmax of the fixed image are values obtained by measuring the solid portion of the image using a surface roughness measuring device Surfcom manufactured by Tokyo Seimitsu Co., Ltd.

Further, in the case of a fixing roller to which no oil is applied, even if the toner contains a release agent, if the toner is compatible with the resin (binder resin), the release agent is fixed at the time of fixing. There is a case where an image which is hard to seep and has a sufficient offset can not be obtained. Therefore, it is preferable to fix the toner in which the release agent is dispersed. By fixing the toner in which the incompatible release agent is dispersed, it is easy to increase the margin until the occurrence of offset. The compatibility and incompatibility of the release agent and the binder resin and the dispersion state of the release agent can be confirmed by a transmission electron microscope, and the definition of the compatibility and incompatibility in the present invention is:
This is based on a 100,000-times enlarged photograph using a transmission electron microscope.

The toner has a weight average molecular weight of 1500.
By including a resin component having a molecular weight of 0 to 40,000 and a molecular weight of 100,000 or more, a fixed image with more margin for offset can be obtained. These molecular weight distributions are measured by GPC (gel permeation chromatography) as follows. The column was stabilized in a heat chamber at 40 ° C., and THF was passed through the column at this temperature at a flow rate of 1 milliliter per minute as a solvent, and the sample concentration was 0.0
A THF sample solution of the resin adjusted to 5 to 0.6% by weight
Inject 00 μl and measure. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Ch
electronic Co. Alternatively, a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , manufactured by Toyo Soda Kogyo Co., Ltd.
1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ ,
3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48
It is appropriate to use × 10 ⁶ and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

Furthermore, since the vicinity of the medium gloss is where the change in the gloss is large, it is easy to deviate from the appropriate gloss and the surface state when continuously obtaining images. In the present invention, by containing a non-linear resin in the resin, a more stable image can be obtained even with a medium gloss.

Examples of the non-linear resin include a cross-linked resin having a THF-insoluble component. However, in this case, if the amount of the THF-insoluble component is large, a medium gloss may not be obtained.
The content of the HF-insoluble component is preferably 1% by weight or less based on the total amount of the binder resin. In addition, even if it is a crosslinked resin, THF
There may be no insoluble components. In such a case, an operation of giving a cross-linking component at the stage of polymerizing the resin is performed,
This is the case where the degree of crosslinking was not so high as to become a THF-insoluble component. Even in this case, it is enough to obtain a stable image. The surface state of the fixed image is easily affected by the surface state of the fixing paper. Therefore, the surface roughness Rz of the fixing paper
Is set to 30 μm or less, the influence of the surface properties of the fixing paper is reduced, and it becomes easy to obtain an intended fixed image.

The soft roller in the present invention is a fixing roller made of an elastic material having low surface energy and heat resistance, such as silicon rubber or fluorine rubber, and may have another layer on the surface. The pressure roller is soft,
It can be either hard. As the release oil in the present invention, silicone oil containing various modified products is favorably used. In particular, when the fixing roller is made of a fluorine-containing resin, silicon fluoride oil is preferable.

The binder resin of the toner according to the present invention comprises a vinyl resin, a polyester resin or a polyol resin, or a mixture of these resins.

Examples of the vinyl resin include styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and homopolymers of substituted styrenes: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene- Vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylic acid Methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer Styrene-based copolymers such as polymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyacetic acid Vinyl etc. That.

The polyester resin is composed of a dihydric alcohol as shown in the following group A and a dibasic acid salt as shown in the group B. May be added as the third component. Group A: ethylene glycol, triethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A , Polyoxypropylene (2,2) -2,2'-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2'-bis (4-hydroxyphenyl) propane and the like. Group B: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linoleic acid, or Esters of these acid anhydrides or lower alcohols. Group C: tri- or higher-valent alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and tri- or higher-valent carboxylic acids such as trimellitic acid and pyromellitic acid.

As the polyol resin, an alkylene oxide adduct of a dihydric phenol of an epoxy resin or a compound having one active hydrogen in a molecule which reacts with a glycidyl ether and an epoxy group, and an active hydrogen reacting with an epoxy resin are used. Examples include those obtained by reacting two compounds in a molecule.

In addition, the following resins can be mixed and used as required. Epoxy resin, polyamide resin, urethane resin, phenol resin, butyral resin, rosin, modified rosin, terpene resin, etc. A typical example of the epoxy resin is a polycondensate of a bisphenol such as bisphenol A or bisphenol F with epichlorohydrin.

The releasing agent for the toner in the present invention includes:
Natural waxes such as candelilla wax, carnauba wax and rice wax, montan wax, paraffin wax, sasol wax, low molecular weight polyethylene, low molecular weight polypropylene, alkyl phosphate and the like. Among these, those incompatible with the binder resin are selected.

As the colorant of the toner in the present invention,
Dyes or pigments capable of obtaining toners of yellow, magenta, cyan, and black can be used. For example, carbon black, lamp black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, lake, chaco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, etc. Any conventionally known dyes and pigments such as dyes and pigments can be used alone or in combination. The amount of these colorants to be used is generally 1 to 30% by weight, preferably 3 to 20% by weight, based on the binder resin.

It is preferable to use a charge control agent for imparting chargeability to the toner and to obtain a stable charge amount.
As the charge control agent in this case, it is preferable to add a transparent to white substance that does not impair the color tone of the color toner to stabilize and impart the toner to a negative polarity or a positive polarity. Specifically, quaternary ammonium salts, imidazole metal complexes and salts are used as the positive electrode, and salicylic acid metal complexes and salts, organic boron salts, calixarene-based compounds and the like are used as the negative electrode.

The toner composition as described above is prepared by a well-known toner mixing method and a pulverizing method.

[0028]

Next, the present invention will be described more specifically with reference to examples. First, a fixing device and toner are prepared.

(Fixing Device A) Fixing roller: 60 mmφ, thickness of 2 mm silicone rubber Pressure roller: 60 mmφ, thickness of 8 mm silicone rubber Release oil: methyl silicone oil Surface pressure: 4.2 to 6.3 kgf / cm ² Variable in range Standard fixing temperature: 160 ° C

(Fixing Device B) Fixing roller: 40 mmφ, 5 mm thick silicon rubber coated with 50 μm thick PFA Pressing roller: 40 mmφ, 20 mm thick PFA Release oil: Silicon fluoride oil Surface pressure: 1. Variable in the range of 9 to 4.4 kgf / cm ² Standard fixing temperature: 150 ° C

(Fixing device C) A device in which the releasing oil of the fixing device B is not applied.

(Fixing device D) Fixing roller: 60 mmφ, 2 mm thick silicon rubber coated with 30 μm thick PFA Pressure roller: 60 mmφ, 1 mm thick silicon rubber coated with 30 μm thick PFA Surface pressure: Variable in the range of 4.7 to 6.5 kgf / cm ² Standard fixing temperature: 150 ° C

(Fixing device E) Fixing roller: 40 mmφ, PFA having a thickness of 20 mm Pressure roller: 40 mmφ, PFA coated with 50 μm thick silicon rubber having a thickness of 5 mm Release oil: Silicon fluoride oil Surface pressure: 1. Variable in the range of 9 to 4.4 kgf / cm ² Standard fixing temperature: 140 ° C

(Fixing device F) A device in which the releasing oil of the fixing device D is not applied.

(Toner a) Binder resin: polyol resin (no THF-insoluble component) 100 parts by weight Colorant For yellow toner: disazo yellow pigment 5 parts by weight (CI Pigment Yellow 17) For magenta toner: quinacridone magenta Pigment 4 parts by weight (CI Pigment Red 122) For cyan toner: copper phthalocyanine blue pigment 2 parts by weight (CI Pigment Blue 15) For black toner: carbon black 6 parts by weight Charge control agent: zinc salt of salicylic acid derivative 2 parts by weight After thoroughly mixing the above materials for each color with a blender, 10
The mixture was melt-kneaded with a twin-screw extruder heated to 0 to 110 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, the mother colored particles 10
0 parts by weight, 0.8 parts by weight of hydrophobic silica was mixed with a Henschel mixer, and yellow, magenta,
Cyan and black toners were obtained. The toner a had a weight average molecular weight of 17000 and no component having a molecular weight of 100,000 or more.

(Toner b) Binder resin: polyol resin (same as toner a) 95 parts by weight Release agent: polyethylene wax 5 parts by weight Colorant, charge control agent: same as toner a The above materials are used for each color. After thoroughly mixing with a blender,
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The toner b has a weight average molecular weight of 17000 and a molecular weight of 1 similarly to the toner a.
There were no more than 100,000 components.

(Toner c) Binder resin: polyester resin (no THF-insoluble component) 100 parts by weight Colorant, charge control agent: same as toner a After the above materials are sufficiently mixed for each color by a blender, 10
The mixture was melt-kneaded with a twin-screw extruder heated to 0 to 110 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, the mother colored particles 10
0.5 parts by weight of hydrophobic silica was mixed with a Henschel mixer with respect to 0 parts by weight, and yellow, magenta,
Cyan and black toners were obtained. Although the form of the molecular weight distribution of the toner c is different from that of the toner a, there was no component having a weight average molecular weight of 17000 and a molecular weight of 100,000 or more.

(Toner d) Binder resin: polyol resin (no THF-insoluble component) 93 parts by weight Release agent: 7 parts by weight of carnauba wax Colorant, charge control agent: same as toner a Blender of the above materials for each color After mixing well,
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.8 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The weight average molecular weight of this toner d was 44,000, and the ratio of components having a molecular weight of 100,000 or more was 11.9%.

(Toner e) Binder resin: polyol resin (without THF insoluble component) 74 parts by weight Polyester resin 20 parts by weight (THF insoluble component: less than 1% by weight) Release agent: carnauba wax 6 parts by weight Colorant Charge control agent: same as toner a. After sufficiently mixing the above materials for each color with a blender,
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The weight average molecular weight of this toner e was 31,000, and the ratio of components having a molecular weight of 100,000 or more was 9.7%.

(Toner f) Binder resin: styrene-acrylic copolymer resin 65 parts by weight (no THF-insoluble component) Styrene-acrylic copolymer resin 30 parts by weight (no THF-insoluble component, but crosslinked) Release agent ... Sasol wax 5 parts by weight Coloring agent, charge control agent ... Same as toner a After sufficiently mixing the above materials for each color with a blender, 80
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The weight average molecular weight of this toner f was 36,000, and the ratio of components having a molecular weight of 100,000 or more was 9.3%.

(Toner g) Binder resin: polyester resin (no THF-insoluble component) 90 parts by weight Release agent: 10 parts by weight of carnauba wax Colorant, charge control agent: same as toner a Blender of the above materials for each color After mixing well,
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The toner g had a weight average molecular weight of 12,000 and no component having a molecular weight of 100,000 or more.

(Toner h) Binder resin: polyol resin (no THF-insoluble component) 100 parts by weight Colorant, charge control agent: same as toner a After sufficiently mixing the above materials for each color with a blender,
The mixture was melt-kneaded with a twin-screw extruder heated to 0 to 110 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, the mother colored particles 10
0.5 parts by weight of hydrophobic silica was mixed with a Henschel mixer with respect to 0 parts by weight, and yellow, magenta,
Cyan and black toners were obtained. The weight average molecular weight of this toner h was 50,000, and the ratio of components having a molecular weight of 100,000 or more was 13.6%.

(Toner i) Binder resin: Polyol resin (same as toner h) 95 parts by weight Release agent: Carnauba wax 5 parts by weight Colorant, charge control agent: Same as toner a Blender of the above materials for each color After mixing well,
The mixture was melt-kneaded with a twin-screw extruder heated to 90 ° C. The kneaded material was allowed to cool, then coarsely pulverized by a cutter mill, and pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier. Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black colors. The weight average molecular weight of this toner i was 48,000, and the ratio of components having a molecular weight of 100,000 or more was 12.5%.

Each of the toners a to i was made to have an average particle size of 50 μm.
5 parts by weight with respect to 100 parts by weight of a carrier obtained by coating the surface of a ferrite particle with a silicone resin on a silicone resin, were mixed by a turbulator mixer to obtain a two-component developer of each color of yellow, magenta, cyan, and black. . The obtained developer was set in a color electrophotographic copying machine (Pretail 550) manufactured by Ricoh Company, and the fixing device was removed to obtain an unfixed solid image.

Example 1 An unfixed solid image of the toner a was fixed at a fixing temperature of 140 ° C., 150 ° C. (standard fixing temperature), 160 ° C. using a fixing device B.
To obtain a fixed image. At this time, the surface pressure of the fixing device A is 3.
It was adjusted to 5 kgf / cm ² and fixed on paper having a surface roughness (Rz) of 33 μm. The glossiness of the fixed image at each of these temperatures,
Table 1 shows the measurement results of the surface roughness Rz and the surface roughness Rmax at 160 ° C. The obtained image was a clear color image with medium gloss and no occurrence of offset. Since the difference between Rmax and Rz at a fixing temperature of 160 ° C. was large, there was a concern that a slight offset would occur. Furthermore, the temperature higher than 160 ° C is 5
When the temperature at which hot offset occurs was examined by changing the fixing temperature for each ° C, the offset occurrence temperature was 175 ° C.
And there was room for the offset occurrence temperature.

Example 2 An unfixed solid image of toner c was fixed using fixing device A at fixing temperatures of 150 ° C., 160 ° C. (standard fixing temperature), and 170 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device was 5.2.
the kgf / cm ^2, was fixed to the sheet surface roughness (Rz) 33 .mu.m. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 170 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. The difference between Rmax and Rz at a fixing temperature of 170 ° C. is 7 μm.
m and smaller than 10 μm, there was no generation of a slight offset. Further, when the fixing temperature was changed every 5 ° C. on the higher side than 170 ° C. and the temperature at which hot offset was generated was examined, the offset generating temperature was 190 ° C., and there was room for the offset generating temperature.

Example 3 An unfixed solid image of toner a was fixed using fixing device C at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), and 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device was 3.5.
the kgf / cm ^2, was fixed to the sheet surface roughness (Rz) 33 .mu.m. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. Further, when the fixing temperature was changed every 5 ° C. on the higher side than 160 ° C. and the temperature at which hot offset occurred was examined, the offset generating temperature was 170 ° C., and there was room for the offset generating temperature. Although the fixing roller was not coated with oil, it was a toner having an offset margin, and thus was not affected by the roughness of the fixing surface due to peeling of the oil layer, and the surface roughness was small.

Example 4 An unfixed solid image of toner b was fixed using fixing device D at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), and 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device is 4.8.
the kgf / cm ^2, was fixed to the sheet surface roughness (Rz) 33 .mu.m. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. Further, when the fixing temperature was changed every 5 ° C. on the higher side than 160 ° C. and the temperature at which hot offset occurred was examined, the offset generating temperature was 180 ° C. Since the toner b is a toner in which the release agent is dispersed, the releasability is improved, and the margin to the temperature at which the offset occurs is widened.

Example 5 An unfixed solid image of toner d was fixed using fixing device D at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), and 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device is 4.8.
the kgf / cm ^2, was fixed to the sheet surface roughness (Rz) 33 .mu.m. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. Further, when the fixing temperature was changed every 5 ° C. on the higher side than 160 ° C. and the temperature at which hot offset occurred was examined, the offset generating temperature was 185 ° C. By containing an appropriate high molecular weight component, the glossiness was reduced, but was within the appropriate gloss range, and the margin to the offset occurrence temperature was widened.

Example 6 A fixed image was obtained in the same manner as in Example 5, except that the surface pressure of the fixing device of Example 5 was changed to 5.5 kgf / cm ² .
The glossiness, surface roughness Rz and 16 of the fixed image at each temperature
Table 1 shows the measurement of the surface roughness Rmax at 0 ° C. The obtained image was a clear color image with medium gloss and no occurrence of offset. The offset generation temperature was 180 ° C. Increasing the surface pressure increases the amount of heat applied to the toner and easily causes offset, but only lowers the temperature by 5 ° C. and has room for the offset occurrence temperature.

Example 7 The procedure of Example 5 was repeated, except that the surface pressure of the fixing device of Example 5 was changed to 4.2 kgf / cm ² and the fixing paper was changed to one having a surface roughness (Rz) of 29 μm. Thus, a fixed image was obtained. The glossiness, surface roughness Rz, and 16 of the fixed image at each temperature
Table 1 shows the measurement of the surface roughness Rmax at 0 ° C. The obtained image was a clear color image with medium gloss and no occurrence of offset. The offset generation temperature was 190 ° C. By using fixing paper having a small surface roughness, the same gloss as in Example 5 was obtained even when the surface pressure was reduced. And, the margin to the hot offset occurrence temperature is also widened. Also, by lowering the surface pressure, damage to the fixing roller can be reduced, which leads to improvement in durability of the fixing roller.

Example 8 An unfixed solid image of the toner e was fixed at a fixing temperature of 140 ° C., 150 ° C. (standard fixing temperature), 160 ° C. using a fixing device D.
To obtain a fixed image. At this time, the surface pressure of the fixing device is 4.8.
The pressure was adjusted to kgf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. Although a resin containing a THF-insoluble component was used, the toner did not have a THF-insoluble component due to shearing force due to kneading, and the gloss did not fall below an appropriate range. Rather, the change in gloss due to temperature was reduced, and the change in gloss during continuous copying was reduced. Further, the offset occurrence temperature was 185 ° C., and there was a margin before the offset occurrence temperature.

Example 9 An unfixed solid image of toner f was fixed using fixing device D at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), and 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device is 4.8.
The pressure was adjusted to kgf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 1. The obtained image is
It was a clear color image with medium gloss and no offset. It is a styrene-acrylic resin that is less glossy than polyester resin, and it is not a resin containing a THF-insoluble component. There was no. In addition, the change in gloss due to temperature was reduced, and the change in gloss during continuous copying was reduced.

[0054]

[Table 1]

Comparative Example 1 An unfixed solid image of toner d was fixed using fixing device E at fixing temperatures of 130 ° C., 140 ° C. (standard fixing temperature), and 150 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device was 2.0 k.
gf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. Since the fixing device E is a hard roller, among the fixed images, the fixed images at 130 ° C. and 140 ° C. did not have any offset, but had low gloss. Also, 1
At 50 ° C., an offset occurred, and the gloss was not measured. These are shown in Table 2.

Comparative Example 2 An unfixed solid image of toner d was fixed using fixing device F at fixing temperatures of 130 ° C., 140 ° C. (standard fixing temperature), 150 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device is 2.0
The pressure was adjusted to kgf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. The fixing device F is a hard roller, and is not coated with oil. The fixed image at 130 ° C. had no offset, but had low gloss and
For 150 ° C. and 150 ° C., offset occurred. These are shown in Table 2.

Comparative Example 3 An unfixed solid image of toner h was fixed using fixing device D at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), and 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device was 4.2.
The pressure was adjusted to kgf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 2. Although the gloss increased to 160 ° C, the surface roughness Rz was 160 ° C from 150 ° C.
° C was greater. The surface roughness Rmax at 160 ° C. was particularly large, and there was no offset to the fixing paper. However, a small amount of toner was transferred to the fixing roller side, and the oil application pad was stained. Further, when the fixing temperature was changed every 5 ° C. on the higher side than 160 ° C. and the temperature at which hot offset occurred was examined, the offset generating temperature was 170 ° C.
There was no margin before the offset occurrence temperature.

Comparative Example 4 Unfixed solid image of toner i was fixed using fixing device D at fixing temperatures of 140 ° C., 150 ° C. (standard fixing temperature), 160 ° C.
To obtain a fixed image. At this time, the surface pressure of the fixing device was 4.2 k.
gf / cm ² and fixed on paper having a surface roughness (Rz) of 29 μm. The glossiness and surface roughness Rz of the fixed image at each of these temperatures and the surface roughness Rmax at 160 ° C. were measured, and the results are as shown in Table 2. All the fixed images were within the proper gloss range, but the gloss did not change between 150 ° C and 160 ° C. Further, the surface roughness Rz was larger at 160 ° C., and the Rmax at 160 ° C. was considerably larger than Rz. When the fixed image at 160 ° C. was observed in detail, a slight offset occurred.

[0059]

[Table 2]

Table 3 summarizes the evaluations of Examples 1 to 9 and Comparative Examples 1 to 4. In Table 3, ○ indicates good and X indicates bad.

[Table 3- (1)]

[0061]

[Table 3- (2)]

[0062]

According to the fixing method of the present invention, it is possible to obtain a stable, full-color image having a sufficient medium gloss and a sufficient margin to the occurrence of offset.

Claims (7)

[Claims] In a heating roller fixing method, a fixing roller is a soft roller made of an elastic material, and has a glossiness of a fixed image of 10 to 40 when fixed at a standard fixing temperature in a range of -10 ° C to + 10 ° C. %, Surface roughness Rz is 10μ
m, which is smaller than m. 2. In a heating roller fixing method, a fixing roller is a soft roller made of an elastic body coated with a release oil, and when a fixing image is fixed at a standard fixing temperature in a range of −10 ° C. to + 10 ° C., a fixed image is formed. Glossiness is 10-40%,
A full-color toner fixing method, wherein the surface roughness Rz is smaller than 10 μm, and Rmax−Rz does not exceed 10 μm. 3. In a heating roller fixing method, the fixing roller is a soft roller made of an elastic body to which no release oil is applied, and when a fixing image is fixed within a standard fixing temperature range of -10 ° C. to + 10 ° C., a fixed image is formed. Gloss 10-40
%, Surface roughness Rz is smaller than 10 μm, and Rmax−R
A full-color toner fixing method, wherein z does not exceed 8 μm. 4. The full-color toner fixing method according to claim 1, wherein the toner is fixed using a toner containing at least a colorant, a resin, and a release agent incompatible with the resin. 5. The method according to claim 1, wherein the weight average molecular weight is 15,000 to 40,
The full-color toner fixing method according to claim 1, wherein the fixing is performed using a toner containing a resin component having a molecular weight of 100,000 or more. 6. The full-color toner fixing method according to claim 1, wherein the fixing is performed using a toner containing a non-linear resin. 7. The full-color toner fixing method according to claim 1, wherein the fixing is performed on a paper or a film having a surface roughness Rz of 30 μm or less.