JP2002156789A - Method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming images, which starts operation quickly by using an image forming toner, having proper low-temperature fixing property and thermal storage property. SOLUTION: The method for forming images includes a fixing operation for heating and fixing a toner image, by making support body carrying the toner image to pass through between two rollers. The fixing roller used for the fixing operation and in contact with the toner image support face is a hallow roller having <=1.0 mm thickness. The surface pressure (load on rollers/ contact area) applied between two rollers is <=1×105 Pa. The toner contains mainly a polyester resin as the binder resin, a coloring agent and wax. The mol.wt. distribution of the toner by GPC for the THF-soluble content of the toner shows at least one peak, in the region extending from 1,000 to 10,000 and the mol.wt. at half-width of the distribution is <=15,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method used for developing an electrostatic latent image such as an electrophotographic method, an electrostatic recording method, and an electrostatic printing method, and more particularly to a low-temperature fixing property and a heat preserving property. The present invention relates to an image forming method using a heat roller fixing method which is capable of quick start and uses a heat roller fixing method which can be quick-started by using an image forming toner which is compatible with the above.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, U.S. Pat. No. 2,297,691 and Japanese Patent Publication No. 49-23910 are used.
Various methods are described in Japanese Patent Publication No. JP-A-43-24748 and Japanese Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means.
Next, the latent image is developed using toner, and if necessary, a toner powder image is transferred to paper or the like, and then fixed by heating, pressing, or solvent vapor to obtain a copy image.

As a fixing method in electrophotography, a heating roller method is widely and generally used because of its high energy efficiency. Further, as in recent low-temperature fixing and high-speed copying for energy saving, thermal energy given to toner at the time of fixing tends to be small. In addition, from the viewpoint of energy saving regarding power during machine standby, the rise time from the standby mode to the use mode is required to be shortened, and in order to increase the thermal energy efficiency in the fixing method and the heating roller method, which have extremely high thermal efficiency, The thickness of the fixing roller on the side in contact with the toner image supporting surface is 1.0 mm
Attempts have been made to: This makes it possible to reach a desired temperature in a very short time, thereby enabling a quick start. However, since the strength of the fixing roller itself is reduced, the pressure (surface pressure) applied to the toner from the fixing roller cannot be reduced. Under such circumstances, there is a need for a toner that does not have a surface pressure dependency that can be fixed even at a low pressure and that can be fixed at a low temperature. In general, it has been attempted to improve low-temperature fixability by using a resin or wax having a low softening point as a toner used in such a fixing process. However, since such a low-temperature fixing toner is sensitive to heat, it is known that a so-called blocking occurs in which the toner is melted and solidified by the heat of the machine used or the heat during storage. Also, it is difficult to secure a sufficient fixing temperature range, and even if a polyester resin which is said to have relatively good heat preservability in spite of its good low-temperature fixability is used, a configuration that has still solved this problem can be obtained. Not. In addition, it is difficult to secure a sufficient fixing temperature range, and even if a polyester resin which is said to have relatively good heat preservability in spite of good low-temperature fixability is used, a toner which has solved this problem can still be obtained. Not.

[0004] In order to solve these problems, several methods using two kinds of polyester resins having different properties have been proposed. For example, a method of mixing a non-linear polyester resin and a linear polyester resin (Japanese Unexamined Patent Publication No.
0-90344), a crosslinked polyester resin having a Tg of 50 ° C. or more and a softening point of 200 ° C. or less, and a softening point of 150
A method of mixing a linear polyester resin having a MW of 3,000 to 50,000 or lower (described in JP-A-64-15755), a non-linear high-molecular polyester resin having a MW of 5,000 or more and a dispersion ratio of 20 or more and MW1 5,000-5,000
00, a method of incorporating a non-linear polyester resin having a dispersion ratio of 4 or less (described in JP-A-2-82267), a method of preparing a linear polyester resin having an acid value of 5 to 60 and a non-linear polyester resin having an acid value of less than 5 A method of incorporating an organometallic compound into a resin (described in JP-A-3-229264),
A method in which a saturated polyester resin is mixed with a different polyester resin having an acid value ratio of 1.5 or more (JP-A-3-4147).
0 publication). However, in recent years, low-temperature fixing has been increasingly advanced, and further constant-temperature fixing has been demanded. With the miniaturization of the apparatus, securing of low-temperature fixing property and fixing temperature range when using a low-load fixing apparatus and heat preservation have been achieved. Is becoming more difficult.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method capable of quick start by using an image forming toner which satisfies low-temperature fixability and heat preservability.

[0006]

The object of the present invention is to provide a fixing operation for heating and fixing a toner image by passing a support carrying a toner image between two rollers. The fixing roller used in the fixing operation and in contact with the toner image supporting surface is a hollow roller having a thickness of 1.0 mm or less, and a surface pressure (roller load / contact) applied between the two rollers. Area) is 1 × 10 ⁵ Pa or less, the toner contains at least a polyester resin, a colorant, and a wax as a binder resin, and a molecular weight distribution by GPC determined by a THF-soluble component of the toner. Has at least one peak between 1,000 and 10,000, and the half width of the distribution is a molecular weight of 15,000 or less. " (3) that the toner contains at least two kinds of different softening points of at least 25 ° C. by at least 25 ° C. (1) wherein the resin contains a resin, and the value of the molecular weight distribution by GPC determined by the THF-soluble component of each resin has at least one peak between 1,000 and 10,000.
Item or the image forming method according to item (2) ”, (4)
(1) The toner according to the above (1), wherein the toner contains at least two or more resins having different softening points, and the resin having a higher softening point contains 5 to 40% of a chloroform-insoluble content. (5) The image forming method according to any one of the above items (3) to (5), wherein the toner contains a metal salicylate compound. Or the image forming method according to item 1).

The above object is also achieved by (6) a fixing device which heats and fixes a toner image by passing a support carrying a toner image between two rollers. The fixing roller on the side in contact with the surface supporting the toner image among the two rollers is a hollow roller having a thickness of 1.0 mm or less, and a surface pressure (roller load / contact) applied between the two rollers. Area) is 1 × 10 ⁵ Pa or less, the toner contains at least a polyester resin, a colorant, and a wax as a binder resin, and a molecular weight distribution by GPC determined by a THF-soluble component of the toner. Has at least one peak between 1,000 and 10,000, and the half width of the distribution has a molecular weight of 15,000.
Image forming apparatus characterized by the following ", (7)
“The image forming apparatus according to the above item (6), wherein the toner contains 5 to 40% of a chloroform-insoluble component”, (8) “the toner has at least two kinds of softening points. A polyester resin containing at least 25 ° C. or more, wherein the value of the molecular weight distribution by GPC determined by the THF-soluble component of each resin has at least one peak between 1,000 and 10,000. (6) or the image forming apparatus according to (7) ",
(9) The toner according to (6), wherein the toner contains at least two or more resins having different softening points, and the resin having a higher softening point contains 5 to 40% of a chloroform-insoluble content. (10) The image forming apparatus according to any one of (8) to (8), (10), (10) to (9), wherein the toner contains a metal salicylate compound. The image forming apparatus according to any one of the above items.

[0008] Further, the above object is achieved by (11) the present invention.
"A toner for image formation including a fixing operation of heating and fixing a toner image by passing a support carrying a toner image between two rollers, wherein the toner is a binder resin. Mainly polyester resin, colorant,
The toner contains at least a wax, and has a molecular weight distribution value of 100 based on GPC determined by a THF-soluble component of the toner.
Having at least one peak between 0 and 10000,
The half width of the distribution is a molecular weight of 15,000 or less, and the fixing roller of the two rollers used in the fixing operation, which is in contact with the surface supporting the toner image, is a hollow roller having a thickness of 1. 0 mm or less, and the surface pressure (roller load / contact area) applied between the two rollers is 1 × 10 ⁵ P
a or less, wherein the toner is an image forming toner,
(12) “The toner for image formation according to the above (11), characterized by containing 5 to 40% of chloroform-insoluble matter”, (13) “At least two or more kinds of softening points are 2
Contains polyester resins that differ by 5 ° C or more, and the T
(11) or (12), wherein the value of the molecular weight distribution by GPC determined by the HF soluble component has at least one peak between 1,000 and 10,000. Image Forming Toner ", (14)
“The resin containing at least two or more resins having different softening points and having a higher softening point has a chloroform insoluble content of 5%.
(15) The image forming toner according to any one of the above items (11) to (13), characterized by containing a metal salicylate compound. The image forming toner according to any one of the above items (11) to (14) ".

Hereinafter, the present invention will be described in detail. In the present invention, (1) achieving a quick start by using a specific thin-wall, low-surface-pressure heat-fixing roller (requires a low-temperature fixing toner having little dependency on surface pressure), and (2) a sharpened molecular weight of the toner Realization of low-temperature fixability by adopting specific distribution resin, (3) improvement of hot offset resistance and improvement of storage stability by use of specific toner in which chloroform-insoluble content is specified, and (4) two or more kinds of softening points are different, and molecular weight is different. By blending a specific polyester resin with a sharp distribution into the toner, the absolute amount of the low molecular weight region can be increased (it is impossible with a single resin design) to achieve further constant temperature fixing. (5) In addition, since the high molecular weight resin forms an island in the sea of the low molecular weight toner resin and the high molecular weight component (gel component) is not cut, Door-offset properties also have achieved good.

That is, the inventors of the present invention have conducted intensive studies, including a fixing operation for heating and fixing a toner image by passing a support carrying a toner image between two rollers. The fixing roller in contact with the toner image supporting surface is a hollow roller having a thickness of 1.0
mm or less, the surface pressure (roller load / contact area) applied between the two rollers is 1 × 10 ⁵ Pa or less, and the toner mainly contains a polyester resin, a colorant, and a wax as a binder resin. In a toner containing at least a polyester resin, a colorant, and a wax as a binder resin, the TH of the toner is mainly used.
The molecular weight distribution determined by GPC determined from the F-soluble component has at least one peak between 1,000 and 10,000, and the half width of the distribution is 15,000 or less in molecular weight. I found it.

Here, when the peak of the molecular weight distribution of the toner by GPC is less than 1000, a problem is particularly observed in the hot offset property, and there is a problem in compatibility with the low-temperature fixing property. Further, when there is a peak in a portion larger than 10,000, there is a problem in low-temperature fixability. In particular, when the half width of the distribution was larger than 15,000, the low-temperature fixability was poor, and remarkable deterioration was observed particularly in the case of using thick paper.

It has also been found that, particularly when the toner contains 5 to 40% of a chloroform-insoluble content, a toner having a high latitude in hot offset property and eliminating the above-mentioned disadvantage can be obtained without impairing low-temperature fixability. did. Here, when the chloroform-insoluble content is more than 40%, the hot offset property is further improved, but the low-temperature fixing property is deteriorated, and a heat fixing roller having a low surface pressure as in the present invention is particularly used. The device used showed significant deterioration.

In addition, the toner particularly contains at least two kinds of polyester resins whose softening points are different from each other by 25 ° C. or more, and the value of the molecular weight distribution by GPC determined by the THF-soluble component of each resin is between 1,000 and 10,000. Has at least one peak to solve the above-mentioned drawbacks, and furthermore, it has been found that low-temperature fixing can be achieved.

The resin having a lower softening point contributes to the low-temperature fixing property, and the resin having a higher softening point contributes to the hot offset resistance. It has been found that the toners are compatible with each other, so that the good properties of both resins are selectively obtained, and that a toner having low-temperature fixing and high-temperature hot offset can be obtained. Here, the softening point difference is 2
When the temperature is lower than 5 ° C., the good compatibility of both resins is absorbed, so that a good portion of both resins is absorbed, and it is difficult to achieve both low-temperature fixability and offset resistance.

In particular, the resin having a higher softening point of at least two kinds of resins contained in the toner contains 5 to 40% of a chloroform-insoluble component, so that the above-mentioned drawbacks can be solved and low-temperature fixing can be achieved. It has been found that a toner having good hot offset can be obtained. Here, when the chloroform-insoluble content is more than 40%, the hot offset property is further improved, but a disadvantage that the low-temperature fixability is deteriorated was observed.

GPC (gel permeation chromatography) is measured as follows. Stabilizing the column in a heat chamber at 40 ° C., flowing THF as a solvent through the column at this temperature at a flow rate of 1 ml per minute,
The measurement is performed by injecting 50 to 200 μl of a THF sample solution of a resin prepared to have a sample concentration of 0.05 to 0.6% by weight. 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. Examples of the standard polystyrene sample for preparing the calibration curve include, for example, Pressure Chemical Co. Or, the molecular weight of Toyo Soda Kogyo KK is 6 × 10 ² ,
1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 1
^{0 4, 1.1 × 10 5,} 3.9 × 10 5, 8.6 × 10 5,
It is suitable to use 2 × 10 ⁶ and 4.48 × 10 ⁶ , and to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

The chloroform-insoluble content is measured as follows. Approximately 1.0 g of the binder resin was weighed, and about 50 g of chloroform was added thereto and sufficiently dissolved. The solution was first subjected to centrifugal separation and filtered at room temperature using JIS standard (P3801) 5 type C quantitative filter paper. I do. Subsequently, the filter paper residue is an insoluble component, and is represented by the ratio (wt%) between the used toner and the filter paper residue.
When measuring the chloroform-insoluble content in the binder resin when the toner is used, about 1.0 g of the toner is weighed and the same method as that for the binder resin is used. Is determined separately by thermal analysis.

The Tg of the binder resin is Rig manufactured by Rigaku Corporation.
The measurement is performed at a heating rate of 10 ° C./min with an aku THRMOFLEX TG8110. The softening point of the binder resin was determined by using an elevated flow tester CFT-500 (manufactured by Shimadzu Corporation) with a die diameter of 1 mm and a pressure of 20 kg / c.
It is measured at a temperature corresponding to ま で from the outflow start point to the outflow end point when a 1 cm ² sample is melted and flown out under the conditions of m ² and a heating rate of 6 ° C./min.

Next, the materials used in the toner of the present invention will be described in detail. The polyester resin used in the present invention is obtained by condensation polymerization of an alcohol and a carboxylic acid. Examples of the alcohol used include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol;
1. etherified bisphenols such as 1.4-bis (hydroxymethyl) cyclohexane and bisphenol A;
Other examples include dihydric alcohol monomers and trihydric or higher polyhydric alcohol monomers. Examples of the carboxylic acid include divalent organic acid monomers such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid; 1,2,4-benzenetricarboxylic acid; , 2,5-benzenetricarboxylic acid, 1,2,4
-Cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid And other trivalent or higher polyvalent carboxylic acid monomers. Here, the glass transition temperature T of the polyester resin
g is preferably 55 ° C. or more, more preferably 60 ° C. or more, from the viewpoint of heat storage properties.

In the present invention, a resin other than the polyester resin may be used in combination with the resin component in the toner as long as the performance of the toner is not impaired. In this case, examples of usable resins include, but are not limited to, the following. Polystyrene, chloropolystyrene, poly α-methylstyrene, styrene /
Chlorostyrene copolymer, styrene / propylene copolymer, styrene / butadiene copolymer, styrene / vinyl chloride copolymer, styrene / vinyl acetate copolymer, styrene / maleic acid copolymer, styrene / acrylic acid ester copolymer Polymers (styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / phenyl acrylate copolymer, etc.),
Styrene / methacrylic acid ester copolymer (styrene /
Methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / phenyl methacrylate copolymer, etc.), styrene / α-methyl methacrylate copolymer, styrene / Styrene resins such as acrylonitrile / acrylic acid ester copolymers (homopolymers or copolymers containing styrene or styrene substituents), vinyl chloride resins, styrene / vinyl acetate copolymers, rosin-modified maleic acid resins, phenolic resins Petroleum resins and hydrogenated petroleum resins such as epoxy resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene / ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin.
These resins are not limited to being used alone, and may be used in combination of two or more. In addition, the production method is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.

The toner of the present invention may contain, if necessary, a colorant,
It is also possible to incorporate a charge control agent, another release agent, a fluidity improver, and the like. Examples of the coloring agent include carbon black, lamp black, iron black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane. Any conventionally known dyes and pigments, such as dyes and pigments, can be used alone or in combination, and can be used as a black toner or a full-color toner. The amount of these colorants to be used is generally 1 to 30% by weight, preferably 3 to 20% by weight, based on the toner resin component.

As the charge controlling agent, any conventionally known polarity controlling agent such as a nigrosine dye, a metal complex type dye and a quaternary ammonium salt can be used alone or in combination. The amount of the polarity controlling agent used is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on the toner resin component. In particular, a metal salicylate compound, preferably a complex having a trivalent metal, reacts with a portion having high reactivity between the resin and the wax to form a mild crosslinked structure, which has an effect of improving hot offset resistance. It is known. In addition, particularly, the metal salicylate compound, preferably the metal is iron or zirconium, reacts with a highly reactive portion of the resin and the wax, a mild cross-linked structure,
Alternatively, it has been found that the formation of a bond by chemical affinity has an effect of improving hot offset resistance.

In the present invention, any known release agent can be used as the release agent for the toner. In particular, the use of carnauba wax, montan wax and rice oxide wax, which are free fatty acids, alone or in combination is possible. Can be. Carnauba wax is preferably a microcrystalline wax, and preferably has an acid value of 5 or less and a particle diameter of 1 μm or less when dispersed in a toner binder. The montan wax generally refers to a montan-based wax refined from a mineral, and is preferably a microcrystal and has an acid value of 5 to 14 like carnauba wax. The oxidized rice wax is obtained by oxidizing rice bran wax with air, and preferably has an acid value of 10 to 30. As other release agents, any conventionally known release agents such as solid silicone varnish, higher fatty acid higher alcohol, montan ester wax, and low molecular weight polypropylene wax can be mixed and used. The use amount of these release agents is 1 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the toner resin component.

As the fluidity improver, any conventionally known fluidity improver such as silicon oxide, titanium oxide, silicon carbide, aluminum oxide and barium titanate can be used alone or in combination. The use amount of these fluidity improvers is from 0.1 to 5 parts by weight, preferably from 0.5 to 2 parts by weight, based on the weight of the toner.

Further, the toner of the present invention can be used as a magnetic toner containing a magnetic substance. Examples of the magnetic material contained in the toner include iron oxides such as magnetite, hematite, and ferrite, iron, cobalt, and nickel. Metals or their metals aluminum, cobalt, copper,
Examples include alloys of metals such as lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof. In particular, magnetite is preferred in terms of magnetic properties. These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm, and are contained in the toner in an amount of about 15 to 200 parts by weight, particularly preferably 100 parts by weight of the resin component.
It is 20 to 100 parts by weight with respect to 00 parts by weight.

The toner of the present invention can be used as a one-component toner or a two-component toner. As the carrier used when the toner of the present invention is used as a two-component developer, all known carriers can be used, for example, iron powder, ferrite powder, magnetic powder such as nickel powder, glass beads, and the like. And those obtained by treating these surfaces with a resin or the like.

In the present invention, the resin powder that can be coated on the carrier includes a styrene-acrylic copolymer,
Silicone resin, maleic acid resin, fluorine resin, polyester resin, epoxy resin and the like are available. In the case of a styrene-acrylic copolymer, those having a styrene content of 30 to 90% by weight are preferred. In this case, the styrene content is 30
If the amount is less than 90% by weight, the developing characteristics are low. If the amount is more than 90% by weight, the coating film becomes hard and easily peels off, shortening the life of the carrier.

Further, the resin coating of the carrier in the present invention may contain an adhesion-imparting agent, a curing agent, a lubricant, a conductive material, a charge control agent and the like in addition to the above-mentioned resin.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. Table 1 shows the detailed results.
An example of the fixing device used in the present invention is shown in FIG. (1) indicates a fixing roller, and (2) indicates a pressure roller. The fixing roller (1) has a surface of a metal cylinder (3) made of a high thermal conductor such as aluminum, iron, stainless steel or brass, and is provided with RTV, silicon rubber, tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), poly An anti-offset layer (4) such as tetrafluoroethylene (PTFE) is coated. A heating lamp (5) is disposed inside the fixing roller (1). In many cases, the same material as the fixing roller (1) is used for the metal cylinder (6) of the pressure roller (2), and the surface thereof is coated with an offset prevention layer (7) such as PFA or PTFA. Although not always necessary, a heating lamp (8) is arranged inside the pressure roller (2). The fixing roller and the pressure roller rotate by being pressed against each other by springs at both ends. An image receiver S of the toner image T is passed between the fixing roller (1) and the pressure roller (2) to perform fixing.

The fixing device used in the present invention improves the temperature rise characteristics of the fixing roller by setting the thickness of the metal cylinder of the fixing roller to 1.0 mm or less, and can achieve a desired temperature in an extremely short time. You can start up. The preferred thickness of the metal cylinder varies depending on the strength and thermal conductivity of the material used, but is preferably 0.2 to 0.7 m.
m is preferred.

The load (surface pressure) applied between the fixing roller and the pressure roller is preferably 1.5 × 105 Pa or less. The surface pressure is a value obtained by dividing a load applied to both ends of the roller by a roller contact area. The roller contact area is determined by passing a sheet, such as OHP paper, whose surface properties change greatly due to heating, between rollers heated to the feasible temperature, stopping on the way, holding for several tens of seconds, then discharging, and changing the surface properties. Obtain the area of the place where it was done. Although a higher roller surface pressure is advantageous for fixing a toner image, in a fixing device in which the thickness of the metal cylinder of the fixing roller is 1.0 mm or less, a large load is applied because a roller distortion is caused. And the load is 1.5 × 10 ⁵ Pa or less, preferably 0.1 × 10 ⁵ Pa.
It is ^{5 to} 1.0 × 10 ⁵ Pa.

(Evaluation of Fixing Property) A copying machine manufactured by Ricoh Co., Ltd. using a Teflon (registered trademark) roller as a fixing roller.
A copy test was performed on the MF-200 using a device in which the fixing unit was modified, using the combination of the image receiving paper and the toner of the example. By changing the fixing temperature, the cold offset temperature (fixing lower limit temperature) and the hot offset temperature (hot offset resistance temperature) were determined. The minimum fixing temperature of the conventional low-temperature fixing toner is 131 to 140 ° C. under the conventional fixing and fixing conditions.
It is about. The evaluation conditions for the low-temperature fixing were as follows: the linear velocity of the paper feed was 150 mm / sec, the thickness of the fixing roller on the side in contact with the toner image support surface, and the roller load (surface pressure) were 1.1 mm. Two types of fixing machines of 0.5 × 10 ⁵ Pa (conventional conditions) and 1.2 × 10 ⁵ Pa at 0.5 mm (thin wall, low surface pressure) were used. In addition, the evaluation condition of the high-temperature offset was set at a linear speed of paper feeding of 50 mm / sec.

The cold offset generation temperature and the high temperature offset generation temperature were determined as follows. (Low temperature fixability) good ：: 120 ° C. or less, ○: 121 to 130 ° C., □: 131 to 140 ° C., Δ: 141 to 150 ° C., ×: 151 ° C. or more Bad (hot offset) Good ◎: 201 ° C. or more, ：: 200 to 191 ° C., □: 190 to 181 ° C., Δ: 180 to 171 ° C., ×: 170 ° C. or less.

(Evaluation of heat-resistant storage stability)
After placing in a 0 ml glass bottle and tapping the glass bottle about 50 times to solidify the sample, it is left in a high-temperature bath at 50 ° C. for 24 hours, and then the penetration is determined using a penetration tester as follows. Was. (Good) ◎: Penetration, ○: ~ 25mm, □: 25-20m
m, Δ: 20 to 15 mm, ×: 15 mm or less (bad)

Next, a production example of a carrier having a silicone resin used in the present embodiment in a coating layer will be described. This can be performed by known means. (Carrier production example 1) Composition of coating layer forming liquid Silicon resin solution (SR2100 manufactured by Toray Silicone Co., Ltd.) 100 parts Carbon black (# 44 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 4 parts Toluene 100 parts The above formulation was dispersed with a homomixer for 30 minutes. Thus, a coating layer forming liquid was prepared. The coating layer forming solution was prepared with an average particle size of 100 μm.
A carrier A having a coating layer formed on the surface of 1,000 parts by weight of the spherical ferrite was obtained using a fluidized bed type coating apparatus.

(Example 1) 100 parts of a polyester resin (weight average molecular weight 6,100, Tg 64 ° C, chloroform insoluble content 21%) Decarried fatty acid type carnauba wax 5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei Corporation) 10 Part Chromium-containing azo compound 2 parts After sufficiently mixing and mixing the mixture having the above composition in a Henschel mixer, the mixture is rolled at a temperature of 130 to 140 ° C. for about 3 hours.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base. 0.5 wt% of hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner.

Comparative Example 1 A toner similar to that of Example 1 was obtained except that the polyester resin of Example 1 was changed as follows. 100 parts of polyester resin (weight average molecular weight 108,000, Tg 65 ° C, chloroform insoluble content 4%) Molecular weight peak 15,000)

(Comparative Example 2) Except that the thickness of the fixing roller and the roller load (surface pressure) of the fixing roller on the side in contact with the toner image supporting surface of the fixing roller were changed to 2.5 × 10 ⁵ Pa at 1.2 mm. The same experiment as in Example 1 was performed.

(Example 2) Polyester resin 100 parts (weight average molecular weight 5,600, Tg 64 ° C, chloroform insoluble content 8%) Oxidized rice wax 5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei Corporation) 10 parts Chromium-containing azo compound 2 parts After the mixture having the above composition is sufficiently stirred and mixed in a Henschel mixer, the mixture is rolled at a temperature of 130 to 140 ° C. for about 3 hours.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base. 0.5 wt% of hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner.

Example 3 The following developer was used. Polyester resin (A) 50 parts (weight average molecular weight 5,000, Tg 63 ° C, THF insoluble content 0%, softening point 148 ° C, molecular weight peak 4,200) Polyester resin (B) 50 parts (weight average molecular weight 6,100, Tg 62 ° C., chloroform-insoluble content 8%, softening point 102 ° C., molecular weight peak 3,800) De-free fatty acid type carnauba wax 5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei Corporation) 10 parts Chromium-containing azo compound 2 parts After thoroughly stirring and mixing the mixture in a Henschel mixer, the mixture is rolled at a temperature of 130 to 140 ° C. for about 3 hours.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base. 0.5 wt% of hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner.

Example 4 Example 3 was repeated except that the polyester resin (B) of Example 3 was changed to the following.
The same toner was obtained. 50 parts of polyester resin (B) (weight average molecular weight 6,300, Tg 62 ° C, chloroform insoluble content 35%, softening point 100 ° C, molecular weight peak 3,600)

Example 5 The following developer was used. Polyester resin (A) 45 parts (weight average molecular weight 5,100, Tg 64 ° C, THF insoluble content 0%, softening point 142 ° C, molecular weight peak 4,100) Polyester resin (B) 45 parts (weight average molecular weight 5,900, Tg63) C, 23% chloroform insoluble matter, softening point 98 ° C, molecular weight peak 3,500) Styrene / acrylic resin 15 parts (weight average molecular weight 27,000, Tg 67 ° C, chloroform insoluble matter 5%, softening point 142 ° C, molecular weight peak 4) , 500) De-free fatty acid type carnauba wax 5 parts Carbon black (# 44: manufactured by Mitsubishi Chemical Co., Ltd.) 10 parts Chromium-containing azo compound 1 part About 3 at a temperature of ℃
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded material was pulverized and classified by a jet mill, a mechanical pulverizer, or an air classifier to obtain a toner base. 0.5 wt% of hydrophobic silica was added to and mixed with the obtained toner base to obtain a final toner.

Example 6 A toner similar to that of Example 5 was obtained except that the metal-containing azo compound of Example 5 was changed as follows. Iron (III) salicylate compound 1 part

Example 7 A toner similar to that of Example 5 was obtained except that the metal-containing azo compound of Example 5 was changed to the following. 2 parts of zirconium salicylate compound

[0045]

[Table 1]

[0046]

As is apparent from the above detailed and specific description, according to the present invention, a heat-fixing method using a thin-wall, low-surface-pressure fixing roller, and image formation satisfying low-temperature fixability and heat preservability. The use of the toner for use has an extremely excellent effect that an energy-saving image forming method capable of quick start can be provided.

[Brief description of the drawings]

FIG. 1 is an example of a fixing device used in the present invention.

[Description of Signs] 1 Fixing roller 2 Pressure roller 3 Metal cylinder 4 Offset prevention layer 5 Heat lamp 6 Metal cylinder 7 Offset prevention layer 8 Heat lamp T Toner image S Image receiver

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahide Yamashita 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kazuto Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Keiko Shiraishi, Inventor 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Mitsuteru Kato 1-3-6, Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. F term (reference) 2H005 AA01 AA06 CA08 CA14 CA17 CA25 DA02 DA10 EA03 EA06 EA07 FB02 2H033 AA09 AA30 BB03 BB05 BB06 BB13 BB34

Claims (5)

[Claims] 1. A fixing operation for heating and fixing a toner image by passing a support carrying a toner image between two rollers. The fixing roller on the fixing side is a hollow roller having a thickness of 1.0 mm or less, a surface pressure (roller load / contact area) applied between the two rollers is 1 × 10 ⁵ Pa or less, and the toner is The toner contains at least a polyester resin, a colorant, and a wax as a binder resin, and has at least one peak between 1,000 and 10,000 in a molecular weight distribution value by GPC determined by THF-soluble matter of the toner. And the half width of the distribution has a molecular weight of 15.0.
An image forming method characterized by being at most 00. 2. The toner according to claim 1, wherein the insoluble content of chloroform is 5 to 5.
The image forming method according to claim 1, wherein the content is 40%. 3. The toner contains at least two kinds of polyester resins whose softening points are different from each other by 25 ° C. or more, and the molecular weight distribution value by GPC determined by the THF soluble component of each resin is in the range of 1,000 to 10,000. The image forming method according to claim 1, wherein the image forming apparatus has at least one peak. 4. The toner contains at least two kinds of resins having different softening points, and the resin having a higher softening point is
The image forming method according to any one of claims 1 to 3, wherein 5 to 40% of a chloroform-insoluble content is contained. 5. The image forming method according to claim 1, wherein the toner contains a metal salicylate compound.