JP3332680B2 - Image forming method - Google Patents

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 using a toner for developing an electrostatic image, which is suitable for heat fixing used in electrophotography, electrostatic recording, and magnetic recording.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
As described in Japanese Patent Application Publication No. JP-B-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. Forming and then developing the latent image with toner,
Using a direct or indirect means as necessary, after transferring the toner image to a transfer material such as paper, fixing by heating, pressure, heating and pressurizing or solvent vapor, etc. to obtain a copy, and The toner remaining on the photoreceptor without being transferred is cleaned by various methods, and the above steps are repeated.

Further, a general method of forming a full-color image will be described. The photosensitive member of a photosensitive drum is uniformly charged by a primary charger, and image exposure is performed by a laser beam modulated by a magenta image signal of a document. To form an electrostatic latent image on the photosensitive drum, and develop the electrostatic latent image by a magenta developing device having magenta toner to form a magenta toner image. Next, the magenta toner image developed on the photosensitive drum by the transfer charger is transferred to the conveyed transfer material using direct or indirect means.

On the other hand, the photosensitive drum after the development of the electrostatic latent image is neutralized by a static eliminator, cleaned by a cleaning unit, and charged again by a primary charger. A cyan toner image is formed and the cyan toner image is transferred to a transfer material on which the magenta toner image has been transferred.
The same procedure is performed in the same manner as for the black color to transfer the four color toner images to the transfer material. The transfer material having the four color toner images is fixed by the action of heat and pressure by a fixing roller to form a full color image.

[0005] In recent years, such devices have begun to be used not only as office work copiers for copying original manuscripts, but also as printers as personal computer outputs or personal copies for individuals.

[0006] In addition to such fields represented by laser beam printers, the development of plain paper faxes using a basic engine has been rapidly developing.

For this reason, smaller, lighter, faster, higher image quality, and higher reliability have been strictly pursued, and machines have been constructed with simpler elements in various respects. . As a result, the performance required of the toner has become higher, and if the performance of the toner cannot be improved, a better machine cannot be realized. Further, in recent years, demands for color copying have been rapidly increasing along with various copying needs, and further higher image quality, higher resolution, etc. are desired in order to more faithfully copy original color images. From these viewpoints, the toner used in the color image forming method needs to have good meltability and color mixing when heat is applied thereto, and has a low softening point and a low melt viscosity. It is preferable to use a toner having a high melting property.

That is, by using such a sharp melt toner, the color reproduction range of a copy can be widened and a color copy faithful to the original image can be obtained.

However, such a color toner having a high sharp melt property generally has a high affinity with a fixing roller, and tends to be easily offset to the fixing roller during fixing.

Particularly, in the case of a fixing device in a color image forming apparatus, since a plurality of toner layers of magenta, cyan, yellow, and black are formed on a transfer material, offset tends to occur particularly due to an increase in toner layer thickness. It is in.

Conventionally, for the purpose of preventing toner from adhering to the surface of the fixing roller, for example, the roller surface is formed of a material having excellent releasability from the toner, such as silicone rubber or fluorine-based resin. In order to prevent surface fatigue, the roller surface is coated with a thin film of a highly releasable liquid such as silicone oil or fluorine oil. However, this method is extremely effective in preventing toner offset, but has a problem that a fixing device is complicated because a device for supplying an anti-offset liquid is required. Needless to say, this oil application causes delamination between the layers constituting the fixing roller, and consequently shortens the life of the fixing roller. As a transfer material for fixing a toner image by using these fixing devices, various papers, coated papers, plastic films and the like are generally used. In particular, the necessity of a transparency film (OHP) using an overhead projector for presentation has recently attracted attention. In particular, unlike OHP, unlike paper, since the oil absorption capacity is low, the currently obtained copy OHP is inevitably greasy due to oil application, and a large problem remains in the quality of the obtained image. In addition, there is a large possibility that silicone oil and the like will evaporate due to heat and contaminate the inside of the machine, and problems such as processing of collected oil will occur. Therefore, instead of using a silicone oil supply device, instead of supplying the anti-offset liquid during heating from the toner, a method of adding a release agent such as low molecular weight polyethylene or low molecular weight polypropylene to the toner is proposed. Have been. However, if such an additive is added in a large amount in order to obtain a sufficient effect, filming on the photoreceptor and contamination of the surface of the toner carrier such as a carrier or a sleeve are deteriorated, and the image is deteriorated, which is a practical problem. Become. Therefore, a small amount of release agent is added to the toner so as not to deteriorate the image,
It has been practiced to use a device that uses a releasable oil or a device that uses a member such as a web of a take-up type, or a device that cleans the offset toner by using a cleaning pad.

However, especially in the field of full color, the means for containing a release agent as in the prior art, when using OHP as a transfer material, causes high crystallization of the release agent and a difference in refractive index from the resin. Therefore, there arises a problem that the transparency and haze of the image after fixing are slightly reduced.

It is known that a wax is contained in a toner as a release agent. For example, Japanese Patent Publication No. 52-3304
JP, JP-B-52-3305, JP-A-57-5-5
The technology is disclosed in 2574 and the like.

Further, JP-A-3-50559, JP-A-2-79860, JP-A-1-109359, JP-A-62-14166, and JP-A-61-27
3554, JP-A-61-94062, JP-A-61-138259, JP-A-60-25236
No. 1, Japanese Unexamined Patent Publication No. 60-252360, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 0-217366 discloses a technique for containing waxes.

Waxes are used to improve the anti-offset properties of toner at low and high temperatures and to improve the fixability at low temperatures, but, on the other hand, deteriorate the anti-blocking properties and prevent the use of copiers and the like. When the toner is exposed to heat due to a rise in temperature or the like, the developability deteriorates, or when the toner is left for a long period of time, the wax migrates to the toner surface and the developability deteriorates.

No conventional toner satisfies all of these aspects, causing some problems. For example, high-temperature offset resistance and developability are excellent, but low-temperature fixability is just one step away, or low-temperature offset and low-temperature fixability are excellent, but blocking resistance is slightly inferior, and developability at elevated temperatures in the machine And the offset resistance at low and high temperatures cannot be compatible.
HP transparency was extremely bad.

In particular, regarding the transparency of OHP, a proposal is made to add a crystallization nucleating agent or the like to the wax in order to reduce the crystallization of the wax itself (JP-A-4-149559 and JP-A-4-107467). Proposal of using wax having low crystallinity (Japanese Unexamined Patent Publication No. Hei 4-30185)
No. 3, JP-A-5-61238) and by adding a substance having a good compatibility with a binder and a lower melt viscosity than the binder to the binder, to improve the surface smoothness of the toner layer after fixing. Proposal is Japanese Patent Application No. 3-212.
652, etc.

One of the release agents having relatively good transparency and low-temperature fixing performance is montan wax which is a mineral wax.

The following structural formula is used as a montan wax:

[0020]

Embedded image

[Wherein, R represents a hydrocarbon group having 28 to 32 carbon atoms, and n represents an integer. A molecular weight of about 8
The use of wax No. 00 is disclosed in JP-A-1-18566.
0, JP-A-1-185661, JP-A-1-185661
185662, JP-A-1-185661,
A proposal has been made in JP-A-1-238672.
However, none of these is fully satisfactory in terms of transparency and haze (cloudiness) of OHP.

On the other hand, in order to inhibit the crystallinity of the release agent itself, Japanese Patent Application No. 5-11851 discloses the use of an ester wax in which the structure of the release agent itself is broken.
7, Japanese Patent Application No. 5-126180, Japanese Patent Application No. 5-1261
No. 81, and quite good results have been obtained.

However, even in recent full-color fixing devices, high durability and high reliability have been demanded, and the improvement of the binder resin and the release agent of the toner alone without the improvement of the fixing device reduces the image area from a high image area to a low image. Image area image,
Furthermore, it is difficult to stably realize an image forming method applicable to a full-color OHP over a long period of time, and further improvement is desired.

[0024]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method which solves the above-mentioned problems.

Another object of the present invention is to provide an image forming method which is excellent in offset resistance to a recording material for a long period of time.

Still another object of the present invention is to provide an image forming method capable of fixing without applying a large amount of oil or without applying any oil.

Still another object of the present invention is to provide an image forming method capable of obtaining a high-quality full-color OHP having excellent transparency.

[0028]

According to the present invention, there is provided an image forming method for fixing an unfixed toner image carried on a recording material to the recording material by a fixing device which heats and presses with a pressing member. Wherein the toner is an aqueous medium
A toner generated in the medium, the toner contains at least a binder resin, a colorant and a wax, the said wax
Weight average molecular weight (Mw) of 400 or more and 4000 or less
When the number average molecular weight (Mn) is 200 or more and 4000 or less,
And the SP value is 7.5 to 10.5, and the flexural modulus at 23 ° C. of the surface resin of the press- contact member is expressed by Akgf
/ Cm ² , 4000 ≦ A ≦ 10000, and the fixing device does not have an oil application mechanism.

As a result of extensive studies, the present inventors have found that when the flexural modulus A at 23 ° C. of the surface layer resin of the press-contact member of the fixing device is in the range of 4000 to 10000 kgf / cm ² , the toner is melted and becomes transparent. Full color O with excellent properties
When preparing the HP, a part or all of the wax forms an appropriate film, a full-color OHP can be prepared without offsetting the toner, and good offset resistance can be maintained. Can be expressed.

The measurement of the flexural modulus in the present invention was performed on the surface material of the press-contact member according to ASTM test method D790.

The flexural modulus A is 4000 kgf / cm
^{If it is} smaller than ² , the wax which is finely dispersed in the unfixed toner at the time of fixing or is compatible with the binder is re-aggregated, and the color reproducibility is reduced, or the transmittance of full-color OHP is reduced. On the other hand, if it is larger than 10,000 kgf / cm ² , it cannot be homogenized on the pressure contact member, and as a result, fixing unevenness, partial offset and the like occur, and the paper cannot be discharged.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The wax used in the present invention has an appropriate affinity with a binder resin for exhibiting good low-temperature fixing property and anti-offset property, has high hydrophobicity and further has a low melting point. Those having low crystallinity are preferred. Furthermore, the molecular weight distribution of the wax has at least two peaks and / or shoulders, and the weight average molecular weight (M
w) is 400 or more and 4000 or less, number average molecular weight (Mn)
Is preferably 200 or more and 4000 or less. It has been found that the above-mentioned molecular weight distribution may be achieved by a single compound or a plurality of compounds, and as a result, the crystallinity can be inhibited and the transparency is further improved. The method of blending two or more waxes is not particularly limited. For example, a media-type dispersing machine (ball mill, sand mill, attritor, apex mill, koball mill, handy mill) or the like having a melting point equal to or higher than the melting point of the wax to be blended is used. It is also possible to use them for melt blending, or to dissolve wax to be blended in a polymerizable monomer and blend them with a media type disperser or the like. At this time, pigments, charge control agents, polymerization initiators, etc. may be used as additives.

In the present invention, the molecular weight distribution of the wax is G
It is measured by a PC under the following conditions.

[0034] (GPC Measurement Condition) Device: GPC-150C (manufactured by Waters Corporation) Column: GMH-HT30cm ² consecutive (Tosoh Corporation) Temperature: 135 ° C. The solvent: o-dichlorobenzene (0.1% Aionoru added) Flow rate: 1.0 ml / min sample: 0.4 ml of 0.15% sample is injected

The molecular weight of the sample is measured and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample. In addition, Mark-Hou
It is calculated by converting to polyethylene using a conversion formula derived from the wink viscosity formula.

The weight average molecular weight (Mw) of the wax is 40
The number average molecular weight (Mn) is preferably from 0 to 4000 and from 200 to 4000. More preferably, Mw is 400 or more and 3000 or less, and still more preferably 40 or more.
0 or more and 2000 or less, Mn is 200 or more and 3000 or less,
More preferably, it is desired to be 200 or more and 2000 or less. When Mw is less than 400 and Mn is less than 200, the blocking resistance of the toner is significantly deteriorated. When Mw exceeds 4000 and Mn exceeds 4000, the crystallinity of the wax itself is developed, and the transparency is significantly deteriorated.

The wax is preferably used in an amount of 1 to 40 parts by weight (preferably 2 to 30 parts by weight) based on 100 parts by weight of the binder resin of the toner.

In a dry toner production method in which a mixture containing a binder resin, a colorant and a wax is melt-kneaded, cooled, pulverized, and classified to obtain toner particles, the amount of the wax added is
It is preferable to use 1 to 10 parts by weight, more preferably 2 to 7 parts by weight, based on 100 parts by weight of the binder resin.

In a polymerization method in which toner particles are directly obtained by polymerizing a mixture containing a polymerizable monomer, a colorant and a wax, the amount of the wax added is 100 parts by weight of the polymerizable monomer. It is preferable to use 2 to 40 parts by weight, more preferably 5 to 30 parts by weight, and still more preferably 10 to 20 parts by weight.

Polymerization method compared to dry toner production method In a toner production method, a generally used release agent is lower in polarity than a binder resin. Therefore, in a polymerization method in an aqueous medium, a large amount of the release agent is encapsulated inside toner particles. In general, a large amount of a release agent can be used as compared with a dry toner production method, which is particularly effective in preventing an offset during fixing.

If the addition amount is less than the lower limit, the offset prevention effect tends to decrease, and if it exceeds the upper limit, the anti-blocking effect is reduced and the anti-offset effect is liable to be adversely affected. Further, in the case of a polymerization toner, a toner having a wide particle size distribution tends to be generated.

In order to obtain a sufficiently transparent OHP image with a low heat capacity of the fixing device, it is most important to lower the crystallinity of the release agent usually contained in the toner. However, in order to impart more sufficient transparency as a secondary effect, there are some undissolved toner grain boundaries that were not dissolved even after fixing, or the crystallinity of the release agent layer is caused by irregular reflection of light. In addition, the effective light transmittance is reduced, resulting in a reduction in haze. Further, even if the components mixed in the toner are sufficiently dissolved at the time of fixing, if the difference in the refractive index between the dissolved toner layer and the release agent layer formed between the fixing members is large, this is also the case of light. It is not preferable because it causes irregular reflection.

The increase in the irregular reflection of light leads to a decrease in the brightness of the projected image and a decrease in the sharpness of the color. In particular, when a transmission type overhead projector is used, this problem is further increased than when a reflection type overhead projector is used.

That is, in order to reduce the crystallinity of the release agent, it is important to lower the crystallinity of the release agent alone. Further, in order to prevent unmelted toner grain boundaries from being present in the toner fixing layer, the glass transition temperature (T
A material having a small melting enthalpy (ΔH), which is the latent heat of the release agent, is particularly preferable in order to make g) and the melting point (mp) of the release agent as close as possible and to quickly dissolve it with a low energy amount. In addition, it is preferable to appropriately adjust the difference in solubility parameter (SP) between the binder resin and the release agent in order that the molten release layer quickly moves between the binder resin layer and the fixing member to form an anti-offset layer. .

Preferred examples of the present invention from such a viewpoint will be described in detail below.

In the wax used in the present invention, a polyester resin, a styrene-acrylic resin, an epoxy resin, or a styrene-butadiene resin is commonly used as a binder resin for the toner in many cases. Those having similar rates are preferred. As a method of measuring the refractive index, first, a solid sample having a size of vertical (20 to 30) × horizontal (8) × thickness (3 to 10) mm is prepared, and then the adhesion to the prism surface is improved. For example, a method of attaching a small amount of bromonaphthalene to the prism surface, placing a solid sample on the prism surface, and measuring the refractive index is exemplified. Further, as the measuring instrument, for example, an Appe refractometer 2T manufactured by Atago Co., Ltd. may be mentioned.

The difference in the refractive index between the binder resin and the wax at a temperature of 25 ° C. is 0.18 or less, more preferably 0.18.
A value of 10 or less is particularly effective. If the difference in refractive index exceeds 0.18, the transparency of the OHP image is likely to be reduced, and a halftone projected image is not preferable because the brightness becomes low.

The melting point of the wax used in the present invention is 3
The temperature is preferably 0 to 150 ° C, more preferably 5 to 150 ° C.
0-120 ° C is particularly preferred. When the melting point is lower than 30 ° C., the blocking resistance of the toner, the suppression of sleeve contamination and the prevention of contamination of the photoreceptor during copying of a large number of sheets are apt to be reduced.
When the melting point is higher than 150 ° C., excessive energy is required for uniform mixing with the binder resin in the production method of the toner by the pulverization method. On the other hand, in the production method of the toner by the polymerization method, the homogenization into the binder resin is required. However, since the size of the apparatus is increased due to an increase in viscosity or the amount of compatibility is limited, it is not preferable because it is difficult to incorporate a large amount of the apparatus.

The solubility parameter (SP) value is determined by the method of Fedors using the additive properties of atomic groups [Polym.
Eng. Sci. , 14 (2) 147 (1974)].

The SP value of the wax used in the present invention is as follows:
It is preferably in the range of 7.5 to 10.5. A wax having an SP value of less than 7.5 has poor compatibility with the binder resin to be used, and as a result, it is difficult to obtain a good dispersion in the binder resin. Adhesion tends to occur, and the charge amount of the toner tends to change. Further, the density fluctuates easily at the time of ground fog and toner supply. When a wax having an SP value of more than 10.5 is used, blocking between toners is likely to occur when the toner is stored for a long time. Further, since the compatibility with the binder resin is too good, it is difficult to form a sufficient releasable layer between the fixing member and the toner binder resin layer at the time of fixing, and the offset phenomenon is easily caused.

[0051] The melt viscosity of the wax used in the present invention can be measured by using a cone plate type rotor (PK-1) with VT-500 manufactured by HAAKE. Melt viscosity at 100 ° C is 1 to 50 mPas · s
ec, more preferably 3 to 30 m
A wax compound having Pas · sec is particularly preferred. When the melt viscosity is lower than 1 mPas · sec, when a thin layer of the toner layer is coated on the sleeve with a blade or the like in a non-magnetic one-component developing system, the sleeve is easily contaminated by mechanical shearing force. Further, in the two-component developing method, when a toner is developed using a carrier, damage is apt to occur due to a shear force between the toner and the carrier, and burying of an external additive and crushing of the toner are likely to occur. 50
When having a melt viscosity exceeding mPas · sec,
When producing a toner using a polymerization method, the viscosity of the dispersoid is too high, and it is not easy to obtain a toner having a fine particle diameter having a uniform particle diameter, and the toner tends to have a wide particle size distribution.

The measurement of the hardness of the wax includes, for example, a measuring method using a Shimadzu Dynamic Ultra-Micro Hardness Tester (DUH-200). The measurement was performed using a Vickers indenter.
10 μm at a load speed of 9.67 mg / sec under a load of 5 g
After displacing, the sample is held for 15 seconds, and a Vickers hardness is determined by analyzing a dent made on the sample. As a sample, a sample previously melted using a mold having a diameter of 20 mmφ is molded into a column having a thickness of 5 mm. The hardness of the release agent used in the present invention is preferably in the range of 0.3 to 5.0,
More preferably, the Vickers hardness is particularly preferably 0.5 to 3.0.

A toner containing a wax having a Vickers hardness lower than 0.3 is liable to be crushed at a cleaning portion of a copying machine in copying a large number of sheets, easily causing toner fusion on a drum surface, and consequently causing black streaks on an image. Is easy to occur. Further, when multiple image samples are stored while being stacked, toner is transferred to the back surface, so-called show-through tends to occur, which is not preferable. A toner containing a wax having a Vickers hardness of more than 5.0 requires an unnecessarily high pressurizing force for a fixing device used at the time of heat fixing, and requires an unnecessarily high strength design for the fixing device. If a fixing device with a normal pressing force is used, the offset resistance tends to decrease, which is not preferable.

The crystallinity of the wax is preferably 10 to 50%, more preferably 20 to 35%.

When the crystallinity is less than 10%, the toner storability and fluidity tend to deteriorate, and when it exceeds 50%, the transparency of the OHP image tends to deteriorate.

The crystallinity in the present invention is measured by the following formula from the area ratio between the amorphous scattering peak and the crystal scattering peak without using a calibration curve.

[0057]

(Equation 1)

As a measuring device, for example, Rotorflex RU300 (Cu target, point focus, output 50 KV / 250 mA) manufactured by Rigaku Denki Co., Ltd. can be mentioned. The measurement method used the transmission method-rotation method, and the measurement angle was 2θ.
= 5 to 35 °.

As a method for producing the wax preferably used in the present invention, for example, a synthesis method by an oxidation reaction, a synthesis from a carboxylic acid or a derivative thereof, an ester group introduction reaction represented by a Michael addition reaction and the like are used. A particularly preferred method for producing the wax used in the present invention is a method using a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound or a reaction from an acid halide and an alcohol compound from the variety of raw materials and ease of reaction. preferable.

[0060]

(Equation 2)

In order to transfer the above-mentioned ester equilibrium reaction to the production system, the reaction is carried out using a large excess of alcohol or in a Dean-Stark water separator in an aromatic organic solvent capable of azeotropic distillation with water. . Further, a method of synthesizing polyester by adding a base as an acceptor of an acid by-produced in an aromatic organic solvent using an acid halide compound can also be used.

As the binder resin used in the toner of the present invention, the following binder resins can be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene Copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binders include styrene copolymers or polyester resins.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Double such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a bond or a substituted product thereof;
For example, dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like;
Vinyl esters such as vinyl acetate and vinyl benzoate; ethylene-based olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl methyl ether and vinyl Vinyl monomers such as ethyl ether, vinyl isobutyl ether and the like; and vinyl monomers such as one or two or more are used.

The number average molecular weight of the THF-soluble component of the binder resin of the present invention is preferably from 3,000 to 1,000,000.

The styrene-based polymer or styrene-based copolymer may be cross-linked, or may be a resin mixture thereof.

As the crosslinking agent for the binder resin, a compound having mainly two or more polymerizable double bonds may be used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butadiol dimethacrylate; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and 3
Compounds having at least two vinyl groups are used alone or as a mixture. The amount of the polymerizable monomer 1
0.001 to 10 parts by weight based on 00 parts by weight is preferred.

The toner of the present invention may contain a charge control agent.

The following substances control the toner to be negatively charged.

For example, organic metal compounds and chelate compounds are effective, and examples thereof include monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal compounds. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarenes, silicon compounds,
A styrene-acrylic acid copolymer, a styrene-methacrylic acid copolymer, a styrene-acryl-sulfonic acid copolymer, a non-metal carboxylic acid compound, and the like can be given.

The following substances control the toner to be positively charged.

Modified products such as nigrosine and fatty acid metal salts, guanidine compounds, imidazole compounds, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like; Onium salts such as phosphonium salts, which are analogs, and their lake pigments, triphenylmethane dyes and these lake pigments (phosphor tungstic acid,
Phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide,
Ferrocyanide), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; Alternatively, two or more kinds can be used in combination. Among these, nigrosine,
A charge control agent such as a quaternary ammonium salt is particularly preferably used.

These charge control agents are preferably used in an amount of 0.01 to 20 parts by weight (more preferably 0.5 to 10 parts by weight) based on 100 parts by weight of the resin component.

As the colorant used in the present invention, carbon black, a magnetic substance, and a black color tone using a yellow / magenta / cyan colorant shown below are used.

Examples of the yellow colorant include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168, 180 and the like are preferably used.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan coloring agent used in the present invention, 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, 6
2, 66 and the like can be particularly preferably used. These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The amount of the coloring agent is 1 to 100 parts by weight of the resin.
Used in an amount of up to 20 parts by weight.

Further, the toner of the present invention can be used as a magnetic toner by further containing a magnetic material. In this case, the magnetic material can also serve as a colorant. In the present invention, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, hematite, and ferrite;
Metals such as cobalt and nickel or metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium Alloys and mixtures thereof.

The magnetic material used in the present invention is more preferably a surface-modified magnetic material. When the magnetic material is used in a polymerization method toner, the magnetic material is treated with a surface modifier which is a substance having no polymerization inhibition. Any surface modifier may be used as long as it is subjected to a chemical conversion treatment. Examples of such a surface modifier include a silane coupling agent and a titanium coupling agent.

These ferromagnetic materials preferably have an average particle size of 2 μm or less, preferably about 0.1 to 0.5 μm. The amount contained in the toner is preferably about 20 to 200 parts by weight, particularly preferably 40 to 150 parts by weight, per 100 parts by weight of the resin component.

The magnetic properties when a 10K Oersted is applied include a coercive force (Hc) of 20 to 300 Oersted, a saturation magnetization (σs) of 50 to 200 emu / g, and a remanent magnetization (σ
r) Those having 2 to 20 emu / g are preferred.

The additive for imparting various toner properties should have a particle diameter of not more than 1/5 of the volume average diameter of the toner particles from the viewpoint of durability when added to the toner or when added to the toner. Is preferred. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope. As additives for imparting these properties, for example, the following are used.

Examples of the fluidity-imparting agent include metal oxides (such as silicon oxide, aluminum oxide and titanium oxide), carbon black, and carbon fluoride. Those subjected to a hydrophobic treatment are more preferable.

Examples of the abrasive include metal oxides (such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide), nitrides (such as silicon nitride), carbides (such as silicon carbide), and metal salts (calcium sulfate). , Barium sulfate, calcium carbonate, etc.).

Examples of the lubricant include fluorine resin powder (vinylidene fluoride, polytetrafluoroethylene, etc.) and fatty acid metal salt (zinc stearate, calcium stearate, etc.).

Examples of the charge control particles include metal oxides (such as tin oxide, titanium oxide, zinc oxide, silicon oxide, and aluminum oxide) and carbon black.

These additives are used in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the toner particles.
1 to 5 parts by weight are used. These additives may be used alone or in combination of two or more.

The toner of the present invention can be used as a one-component or two-component developer in any developer.

For example, in the case of a magnetic toner in which a magnetic material is contained in a toner as a one-component developer, there is a method of using a magnet built in a developing sleeve to convey and charge the magnetic toner. . When a non-magnetic toner containing no magnetic substance is used, there is a method in which the toner is conveyed by forcibly frictionally charging the developing sleeve with a blade and a fur brush and causing the toner to adhere to the sleeve.

On the other hand, when used as a generally used two-component developer, a carrier is used as a developer together with the toner of the present invention. The carrier used in the present invention is not particularly limited, but is mainly composed of a single ferrite and a composite ferrite composed of iron, copper, zinc, nickel, cobalt, manganese, and chromium. The carrier shape is also important because saturation magnetization and electric resistance can be controlled in a wide range. For example, it is preferable to select a spherical shape, a flat shape, an irregular shape, and the like, and to further control the fine structure of the carrier surface state, for example, the surface unevenness. . Generally, the above inorganic oxide is calcined,
A method of coating the resin after forming carrier core particles in advance by granulation is used.However, from the viewpoint of reducing the load on the toner of the carrier, the inorganic oxide and the resin are kneaded and then pulverized. , A method of obtaining a low-density dispersion carrier by classification, and a method of directly obtaining a polymerized carrier for obtaining a spherical dispersion carrier by suspension-polymerizing a kneaded product of an inorganic oxide and a monomer in an aqueous medium are also used. It is possible to

A system in which the surface of the carrier is coated with a resin or the like is particularly preferable. As the method, any conventionally known method such as a method of dissolving or suspending a coating material such as a resin in a solvent, coating and adhering to a carrier, and a method of simply mixing with a powder can be applied.

The substance to be fixed to the carrier surface varies depending on the toner material. Examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditersharry butylsalicylic acid, and styrene-based compounds. It is appropriate to use resin, acrylic resin, polyamide, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake, silica fine powder, alumina fine powder, etc. alone or in combination, but it is not necessarily limited to this. Not done.

The treatment amount of the above compound is generally preferably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the total amount of the carrier of the present invention.

The average particle size of these carriers is 10 to 100.
μm, preferably 20 to 50 μm.

A particularly preferred embodiment is ferrite whose surface is a combination of a resin such as a fluorine resin and a styrene resin, for example, polyvinylidene fluoride and styrene-methyl methacrylate resin; polytetrafluoroethylene and styrene-methyl methacrylate resin. 90: 1 acrylate resin, fluorine-based copolymer and styrene-based copolymer;
A mixture having a ratio of 0 to 20:80, preferably 70:30 to 30:70, or a silicone resin or the like, 0.01 to 5% by weight, preferably 0.1 to 3% by weight.
Coated and coated ferrite carriers. As the fluorine-based copolymer, a vinylidene fluoride-tetrafluoroethylene copolymer (10:90
To 90:10), and styrene-based copolymers such as styrene-2-ethylhexyl acrylate (20: 8
0-80: 20), styrene-2-ethylhexyl acrylate-methyl methacrylate (20-60: 5-30:
10 to 50).

The coated ferrite carrier has a sharp particle size distribution, provides favorable triboelectric charging properties to the toner of the present invention, and has the effect of improving electrophotographic properties.

When a two-component developer is prepared by mixing with the toner of the present invention, the mixing ratio is 2 to 15% by weight, preferably 4 to 13% by weight, as the toner concentration in the developer. % Usually gives good results. If the toner density is less than 2%, the image density is low, making it impractical. If the toner density is more than 15%, fog and scattering inside the machine are increased, and the useful life of the developer is shortened.

Further, the magnetic properties of the carrier are preferably as follows. The saturation magnetization needs to be ^{20 to} 90 Am2 / kg. To achieve higher image quality,
Preferably, it is 30 to 70 Am ² / kg. If it is larger than 90 Am ² / kg, it becomes difficult to obtain a high quality toner image. If it is less than 20 Am ² / kg, carrier adhesion is likely to occur because the magnetic binding force is reduced.

The method for producing the pulverized toner in the present invention includes a binder resin, the above-mentioned ester wax of the present invention, a pigment or dye as a colorant, a magnetic substance, a charge control agent if necessary,
While the other additives, etc. were thoroughly mixed by a mixer such as a Henschel mixer, a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, a kneader, or an extruder to make the resins compatible with each other. The toner according to the present invention can be obtained by dispersing or dissolving a metal compound, a pigment, a dye, and a magnetic substance, and performing cooling and solidification followed by pulverization and classification.

Further, if necessary, desired additives are sufficiently mixed by a mixer such as a Henschel mixer to obtain the toner for developing an electrostatic image according to the present invention.

The method for producing the polymerized toner used in the present invention includes a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in Japanese Patent Publication No. 56-13945 to obtain a spherical toner, JP-B-36-10231, JP-A-59-53856, and JP-A-59-6.
No. 1842, a method of directly producing a toner by using a suspension polymerization method, and a method of dispersing by directly producing a toner by using an aqueous organic solvent which is soluble in a monomer and insoluble in a polymer obtained. Emulsion polymerization method represented by soap-free polymerization method, which produces a toner by directly polymerizing in the presence of a legal or water-soluble polar polymerization initiator, or after preparing primary polar emulsion polymerization particles in advance,
It is possible to produce a toner using a heteroaggregation method or the like in which polar particles having opposite charges are added and associated.

However, in the dispersion polymerization method, the obtained toner shows a very sharp particle size distribution, but the selection of materials to be used is narrow, and the use of an organic solvent has an effect on the treatment of waste solvent and the flammability of the solvent. From the viewpoint, the manufacturing apparatus is complicated and complicated. The emulsion polymerization method represented by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but when the used emulsifier and initiator terminal are present on the surface of the toner particles, the environmental characteristics are likely to deteriorate.

In the present invention, a suspension polymerization method under normal pressure or under pressure, which can easily obtain a fine particle toner having a sharp particle size distribution, is particularly preferable. A so-called seed polymerization method in which a monomer is further adsorbed on the polymer particles once obtained and then polymerized using a polymerization initiator can also be suitably used in the present invention.

A more preferable toner used in the present invention is produced by a direct polymerization method in which a wax is encapsulated in an outer resin layer by a method of measuring a tomographic plane of the toner using a transmission electron microscope (TEM). It is a thing. From the viewpoint of fixing property, it is necessary to incorporate a large amount of wax into the toner, so that it is necessary to incorporate necessary wax into the outer shell resin. Unless the toner is not encapsulated, the toner cannot be sufficiently pulverized unless a special freeze pulverization is used in the pulverization process, resulting in only a toner having a wide particle size distribution. This is extremely undesirable. In the freezing and pulverization, the device becomes complicated to prevent dew condensation on the device, and if the toner absorbs moisture, the workability of the toner is reduced. Become. As a specific method of encapsulating the wax, the polarity of the material in the aqueous medium is set smaller than that of the main monomer in the wax, and then a small amount of a polar resin or monomer is added. A toner having a so-called core-shell structure in which wax is coated with an outer shell resin can be obtained. To control the particle size distribution and the particle size of the toner, methods such as changing the type and amount of the dispersant that acts as a poorly water-soluble inorganic salt or protective colloid, and mechanical device conditions such as the peripheral speed of the rotor, the number of passes, and the stirring blades The predetermined toner of the present invention can be obtained by controlling the stirring conditions such as the shape, the shape of the container, and the solid content concentration in the aqueous solution.

As a specific method for measuring the tomographic plane of the toner in the present invention, the toner can be obtained by sufficiently dispersing the toner in an epoxy resin which is curable at room temperature and then curing it in an atmosphere at a temperature of 40 ° C. for 2 days. The cured product is stained with ruthenium tetroxide and, if necessary, osmium tetroxide, and then sliced using a microtome with diamond teeth, and cut out using a transmission electron microscope (TEM). Was measured. In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to give a contrast between materials by utilizing a slight difference in crystallinity between the wax used and the resin constituting the outer shell.

In the case where the direct polymerization method is used in the toner production method of the present invention, the toner can be specifically produced by the following production method. A wax, a coloring agent, a charge control agent, a polymerization initiator and other additives are added to the monomer, and a monomer system uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser or the like, and a dispersion stabilizer is contained. Disperse in the aqueous phase using a conventional stirrer, homomixer, homogenizer or the like. Preferably, the stirring speed and time are adjusted so that the monomer droplets have the desired size of the toner particles, and the granulation is performed. Thereafter, by the action of the dispersion stabilizer, the particles may be stirred to such an extent that the particle state is maintained and the particles are prevented from settling. The polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be increased in the latter half of the polymerization reaction, and further, unreacted polymerizable monomers that cause odor at the time of fixing the toner,
In order to remove by-products and the like, a part of the aqueous medium may be distilled off in the latter half of the reaction or after completion of the reaction. After completion of the reaction, the generated toner particles are collected by washing and filtration, and dried.
In the suspension polymerization method, it is generally preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

When a toner is directly obtained by a polymerization method, styrene, o (m-, p-
Styrene-based monomers such as-)-methylstyrene, m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethyl (meth) acrylate (Meth) acrylate monomers such as aminoethyl and diethylaminoethyl (meth) acrylate; and ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide are preferably used.

In the present invention, in order to form a core-shell structure, it is essential to use a polar resin in combination. Polar polymers and copolymers usable in the present invention are exemplified below.

Polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, copolymers with styrene-unsaturated carboxylic acid esters and the like, nitrile monomers such as acrylonitrile, and vinyl chloride and the like Halogen-containing monomers, acrylic acid, unsaturated carboxylic acids such as methacrylic acid, and other unsaturated dibasic acids,
Unsaturated dibasic acid anhydrides, polymers such as nitro monomers or copolymers with styrene monomers, polyesters,
Epoxy resins and the like can be mentioned. More preferred are a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin.

As the polymerization initiator, for example, 2,2′-
Azobis- (2,4-dimethylvaleronitrile), 2,
2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2 ′
Azo or diazo polymerization initiators such as azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butylhydro Peroxide, di-t-butyl peroxide, dixyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,
4-tert-butylperoxycyclohexyl) propane,
A peroxide initiator such as tris- (t-butylperoxy) triazine, a polymer initiator having a peroxide in a side chain, a persulfate such as potassium persulfate and ammonium persulfate, and hydrogen peroxide are used. You.

The polymerization initiator is 0.5 to 20 of the polymerizable monomer.
The addition amount by weight is preferable, and it may be used alone or in combination.

In the present invention, a known crosslinking agent or chain transfer agent may be added to control the molecular weight, and the preferable addition amount is 0.001 to 15 parts by weight.

In the present invention, any suitable stable medium may be used as a dispersion medium for producing a polymerization toner by emulsion polymerization, dispersion polymerization, suspension polymerization, seed polymerization, polymerization using a heteroaggregation method, or the like. Use agent. For example, as inorganic compounds, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. As organic compounds, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and its salts, starch, polyacrylamide, polyethylene oxide, poly (hydroxystearic acid-g-methacrylic acid) A methyl-eu-methacrylic acid) copolymer or a nonionic or ionic surfactant is used.

When the emulsion polymerization method and the heteroaggregation method are used, an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant are used. It is preferable to use 0.2 to 30 parts by weight of these stabilizers based on 100 parts by weight of the polymerizable monomer.

When an inorganic compound is used among these stabilizers, a commercially available one may be used as it is, but in order to obtain fine particles, the inorganic compound may be formed in a dispersion medium.

For finely dispersing these stabilizers, 0.001 to 0.1 parts by weight of a surfactant may be used. This is to promote the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Examples include sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

In the present invention, as the colorant used in the polymerization method toner, it is necessary to pay attention to the polymerization inhibitory property and the water phase migration property of the colorant. It is better to perform a hydrophobic treatment without inhibiting polymerization. In particular, many dyes and carbon blacks have polymerization inhibitory properties, so care must be taken when using them. As a preferable method for surface-treating the dye system, a method in which a polymerizable monomer is previously polymerized in the presence of these dyes is mentioned, and the obtained colored polymer is added to the monomer system. The carbon black may be treated with a substance that reacts with the surface functional group of the carbon black, for example, a polyorganosiloxane, in addition to the same treatment as the above dye.

Next, a fixing device suitable for the present invention will be described.

FIG. 1 is a schematic view showing an example of a heating roller type fixing device.

The apparatus of this embodiment is a cylindrical heating roller 1 as a pressure contact member having a heating means such as a heater 101a inside.
01, and rotates clockwise for fixing.

Reference numeral 102 denotes a cylindrical pressing roller as a pressing rotary member, which is pressed against the heating roller 101 and rotates counterclockwise during fixing.

The recording material P, which is transported from the right by the transport belt 103 and has the unfixed toner T adhered as a toner image, is pressed and heated by the heating roller 101 and the pressure roller 102 to be fixed. It is discharged to the left.

Reference numerals 104a and 104b denote separation claws used for separation in order to prevent the recording material P from being wound around the heating roller 101 or the pressure roller 102 and causing a conveyance failure.

Reference numeral 106 denotes a felt oil pad having a suitable viscosity and impregnated with a release agent such as silicone oil, and 105 denotes a cleaning roller in which brush fibers are implanted in a cylindrical shape. The cleaning roller 105 rotates to remove the toner residue adhering to the peripheral surface of the heating roller and to appropriately supply the release agent. 106 may be omitted.

For example, the heating roller 101 has a thickness of 2 to 5 mm.
A 200-500 mm Al pipe is used as a core metal.
One coated with a μm thick silicone rubber or Teflon is used.

The pressure roller 102 is, for example, about 10 m
A SUS core metal having a diameter of mφ and a peripheral surface thereof coated with silicone rubber with a thickness of about 3 mm is used.

On the other hand, the heating device of the film heating system is compared with other known heating devices such as a heat roller system, a hot plate system, a belt heating system, a flash heating system and an open heating system or an image heating fixing device. In this case, a linear heating element having a low heat capacity can be used as a heating element, and a film having a low heat capacity of a thin film can be used as a film.
It is possible to shorten the wait time (quick start property), suppress the temperature rise in this machine, and in the image heating fixing device, the fixing point and the separation point can be set separately, so that the offset can be prevented. It has advantages such as solving various drawbacks of other system devices and is effective.

The present invention can be used not only as a fixing device but also as a device and a device for heating a material to be heated, such as a device for heating a recording material carrying an image to improve the surface properties, a device for temporarily attaching the material, and the like.

FIG. 2 schematically shows a film heating type apparatus (image heating and fixing apparatus).

Reference numeral 6 denotes a heating element (ceramic heater) fixedly supported on a support 3. A heat-resistant film (fixing film) 1 as a pressing member is pressed on the heating element 6 by a pressure roller 2 as a pressure rotating element. The heat-resistant film 1 and the pressure roller 2 of the press-contact nip portion (fixing nip portion) N formed by the heating element 6 and the pressure roller 2 with the heat-resistant film 1 interposed therebetween. The recording material P on which an image is to be fixed as a material to be heated is introduced, and the press-contact nip N is conveyed together with the heat-resistant film 1 so that the heating element 6 is heated.
Is applied to the recording material P via the heat-resistant film 1 to heat and fix the unfixed visible image (toner image) T on the recording material P to the surface of the recording material P. The recording material P that has passed through the pressure nip N is separated from the surface of the film 1 and transported.

The heating element 6 is an elongated heat-resistant, insulating and highly heat-conductive substrate 7 whose longitudinal direction is perpendicular to the transport direction a of the heat-resistant film 1 or the recording material P as the material to be heated. A resistance heating element 5 formed along the length of the substrate at the center in the short side of the front side of the substrate, power supply electrodes 10 at both longitudinal ends of the resistance heating element 5, and a heating element surface regulating the resistance heating element Is a linear heating element having a low heat capacity as a whole, including a heat-resistant overcoat layer 8 that protects the substrate and a temperature-detecting element 4 such as a thermistor that detects the temperature of the heating element provided on the back side of the substrate.

The heating element 6 is fixedly disposed so that the surface on which the resistance heating element 5 is formed is exposed downward and is adhered and held to the rigid and heat insulating heater support 3.

The heating element 6 is composed of electrodes 10 at both ends of the resistance heating element 5.
The power is supplied to the resistance heating element 5 to generate heat over the entire length thereof, thereby increasing the temperature. The temperature increase is detected by the temperature detecting element 4, and the detected temperature is field-backed to a temperature control circuit (not shown) and Power supply to the resistance heating element 5 is controlled so that the temperature is maintained at a predetermined temperature. That is, the power supply to the resistance heating element 5 is controlled so that the detection output of the temperature detecting element (thermistor) 4 becomes constant during fixing. It should be noted that a heating device using an alternating magnetic field injection may be used instead of the ceramic heater.

The heat-resistant film 1 is formed in an endless belt shape, and one of the rollers around which the film is stretched is used as a driving roller, and is rotated and conveyed by the frictional force between the driving roller and the inner peripheral surface of the film. Alternatively, the pressure roller 2 may be used as a drive roller, or may be configured to be rotated and conveyed by a frictional force between a drive roller provided on the outer surface of the film and the outer peripheral surface of the film in addition to the pressure roller 2.
Is rolled into a long film, and the film is fed out and carried out.

The pressure roller 2 as the pressure rotating body is the same as the pressure roller 102 of the apparatus shown in FIG.
a and a heat-resistant rubber layer 2b having good release properties such as silicone rubber
It is a solid (solid-walled) elastic roller (hereinafter, referred to as a solid roller) made of a material (not shown) and pressed against the surface of the heating element 6 by sandwiching the film 1 with a predetermined pressing force by a bearing means and an urging means (not shown). It is arranged. When the pressure roller 2 is a film drive roller, the roller 2
Is transmitted from a driving means (not shown), and is driven to rotate counterclockwise as indicated by the arrow.

In a preferred embodiment of the present invention, the base layer has an elastic layer, and the outermost layer is a fluororesin layer having a specific contact angle with the wax in the toner, and the base layer is provided between the base layer and the surface layer. This is an elastic roller provided with a fluorine rubber layer having a hardness higher than that of the elastic layer having a thickness of 5 to 10 μm. Further, it is more preferable that the outermost layer of the fluorine resin is mainly composed of FEP.

As another preferred embodiment, as shown in FIG. 2, the above-mentioned elastic roller is used as a pressure rotating body, and a heat-resistant film or a belt member is interposed between the pressure rotating body and the heating body. The heating target is introduced between the heat-resistant member of the pressure-contact nip portion formed by the body and the pressure-rotating member and the pressure-rotating member, and the pressure-contact nip portion is transported together with the heat-resistant member. This is a heating device that applies the heat of the material to the material to be heated via a heat-resistant member.

As still another preferred embodiment, a heat-resistant film or belt member having a conductive layer and a pressing member having a conductive layer, and a magnetic field applied to these conductive layers to generate an eddy current to generate heat. And a heating device for heating the material to be heated by sandwiching and conveying the material to be heated in the nip portion between the heat-resistant member and the pressing member.

With the above configuration, the elastic roller has excellent releasability over a long period of time and good adhesion between the layers, so that the elastic roller has excellent durability and low roller hardness.

Further, as a heating device (fixing device) of a film heating system or a heating roller system using the elastic roller as a pressurizing rotating body, good heating performance is obtained even at low pressure and low temperature.
Since the fixing property can be obtained, the apparatus can be inexpensive.

The layer structure of the pressure roller will be described in detail below.

The elastic layer serving as a base layer plays a role of making a sufficient nip under a low pressure, and is, for example, silicone rubber. The elastic layer preferably has a material hardness of 30 ° or less (JIS-A). When the thickness of the elastic layer is increased and the hardness is decreased, the change in the outer diameter due to heat increases, and particularly when the pressure roller is driven, the image is elongated. Also,
Applying a high pressure increases the torque of the device, which leads to an increase in the cost of the motor and the like.

The fluoro rubber layer provided between the base layer and the surface layer functions as an adhesive for coating the fluoro resin, and has a higher hardness than the elastic layer of the base layer. The reason is that the fluorine adheres to each other, so that the coating property is excellent. The thickness of the fluoro rubber layer is 5
To 10 μm. If the thickness is less than 5 μm, cracks will be formed in the surface layer, and the surface layer will not be formed of the fluororesin. If the thickness is more than 10 μm, the roller hardness increases, and there is a possibility that a sufficient nip may not be obtained at a low pressure, which is not preferable.

The outermost layer of the fluororesin plays a role of securing the toner releasability for a long period of time.
PFA, PTFE and the like. The thickness of the fluororesin layer is 5 to 30 μm. If it is thinner than 5 μm, 10
When printing is performed on 10,000 or more sheets, the releasability may be lost. If the thickness is more than 30 μm, the roller hardness may increase, and a sufficient nip may not be obtained at a low pressure, which is not preferable.

[0146]

Example 1 450 g of a 0.1 M Na ₃ PO ₄ aqueous solution was charged into 710 g of ion-exchanged water, heated to 60 ° C., and then, using a TK homomixer (manufactured by Tokushu Kika Kogyo). 13000 rpm
And stirred. 1.0M-CaCl ₂ aqueous solution 68
g was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, styrene 166 g n-butyl acrylate 34 g copper phthalocyanine pigment 15 g ditertiary-butyl salicylic acid metal compound 3 g saturated polyester 10 g (acid value 11, peak molecular weight 8500) monoester wax 40 g (Mw 500, Mn 400, viscosity 6.5 mPa · s, SP value) 8.6)

The above-mentioned formulation was heated to 60 ° C., and was subjected to 12000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo).
To dissolve and disperse uniformly. In addition, polymerization initiator 2,
2'-azobis (2,4-dimethylvaleronitrile) 1
0 g was dissolved to prepare a polymerizable monomer composition. Said,
The above polymerizable monomer composition was charged into an aqueous medium,
Under a N ₂ atmosphere at ℃ 1 with a TK homomixer
The mixture was stirred at 0000 rpm for 20 minutes to granulate the polymerizable monomer composition. Then, while stirring with a paddle stirring blade, 80
C., and reacted for 10 hours.

After the completion of the polymerization reaction, the mixture was cooled, hydrochloric acid was added to dissolve calcium phosphate, and then filtered, washed with water and dried to obtain polymer particles.

With respect to 100 parts by weight of the obtained particles, BE
2.0 parts by weight of hydrophobic titanium oxide having a specific surface area of 100 m ² / g by the T method was externally added to obtain a toner having an average particle diameter of 6.2 μm.

To 7 parts by weight of this toner, 93 parts by weight of a 35 μm silicone-coated ferrite carrier were mixed, and developer No. 1 was added. It was set to 1.

On the other hand, a commercially available full-color copying machine CLC80
The oil application mechanism was removed from the fixing device of No. 0 (manufactured by Canon) as shown in FIG. A heating / pressing roller as a pressing member covers a surface of a core metal made of a material having good heat conductivity such as aluminum alloy and iron with a heat-resistant elastic layer made of silicone rubber having a Hs of about 25 to 55 ° as a base layer, Further, a roller coated with 10 μm of FEP on the surface layer was used. The heating / pressing roller has a rubber layer thickness of 2 m each.
m / 1 mm. For the surface layer, use Neoflon ND1 manufactured by Daikin Industries, Ltd. at 380 ° C.
It baked for 30 minutes at -400 degreeC. Between the surface layer and the base layer, a fluororubber layer having a hardness higher than that of the elastic layer was used for the primer in a thickness of 5 to 10 μm.

The developer No. 1 with the image area of 20% and 50%
Using two types of original manuscripts, a paper passing test was performed on each of 10,000 sheets.

At this time, the flexural modulus of the surface resin of the roller at 23 ° C. was 6000 kgf / cm ² . Table 1
The results are shown together with OHP permeability.

Comparative Example 1 In Example 1, paraffin wax (Mw 470,
Mn 380, viscosity 6.8 mPa · s, SP value 8.3) except that developer No. 2 was produced.

As for the fixing device, a heat-resistant elastic layer made of silicone rubber having a Hs of about 25 to 55 ° is coated as a base layer on the surface of the cored bar, and the surface layer is coated with ETFE (tetrafluoroethylene-ethylene copolymer: tetrafluoride). Ethylene-
A roller coated with 25 μm of ethylene copolymer) was used. The heating / pressing roller has a rubber layer thickness of 2 mm /
It was configured to be 1 mm. For the surface layer, use Neofolon ETFE film manufactured by Daikin Industries, Ltd.
A fixing device was modified in the same manner as in Example 1 except that the fixing device was baked at a temperature of 400 ° C./400° C. for 30 minutes.

Table 1 shows the results of a paper passing test performed in the same manner as in Example 1. At this time, the flexural modulus at 23 ° C. of the surface resin of the roller was 11,000 kgf / cm ² . It is presumed that the flexural modulus was large and the paper was not discharged.

Comparative Example 2 In Comparative Example 1, the surface resin was selected, and the surface material was 2
Evaluation was performed in the same manner as in Comparative Example 1 except that the flexural modulus at 3 ° C. was 12000 kgf / cm ² , but a satisfactory result was not obtained. This is presumably because the flexural modulus at 23 ° C. of the surface resin was inappropriate.

Comparative Example 3 In Comparative Example 1, the surface layer material had a flexural modulus at 23 ° C. of 16800 kgf / cm ² , and PCTFE (polychlorotrifluoroethylene: ethylene trifluoride chloride resin) was used as the surface layer resin. Except for the above, evaluation was performed in the same manner as in Comparative Example 1, but no satisfactory result was obtained. This is presumably because the flexural modulus of the surface resin at 23 ° C. was inappropriate.

Example 2 In Example 1, PFA was used for the surface material,
The flexural modulus at 6 ° C. is 6800 kgf / cm ² and the surface layer is NEOFLON manufactured by Daikin Industries, Ltd.
Using AD-2CR, the image was formed in the same manner as in Example 1 except that firing was performed at 380 ° C. to 400 ° C. for 30 minutes.
Good results were obtained.

Example 3 A diester wax (Mw 480,
Mn410, viscosity 10.5 mPa · s, SP value 9.1)
The developer 3 was prepared in the same manner as above except that the resin used in Examples 1 and 2 was mixed at a weight ratio of 8: 2 and used as the surface material of the roller. As a result, good results were obtained.

Example 4 In Example 1, a tetraester wax (Mw 43
0, Mn320, and Mw850 have shoulders,
A developer 4 was prepared in the same manner except that a viscosity of 11.6 mPa · s and an SP value of 8.5) were used.
And the resin used in Example 2 was mixed and used in a weight ratio of 6: 4, and the same evaluation was performed.
Good results were obtained.

Example 5 The fixing device was modified to the one shown in FIG.
Flexural modulus at 6000 kgf / cm ²
A good result was obtained when the same procedure was carried out except for the above.

[0163]

[Table 1]

Example 6 In Example 1, a quinacridone pigment was used instead of the copper phthalocyanine pigment. I. Pigment Yellow 180,
Magenta, yellow, and black developers were prepared in the same manner except that carbon black was used, and image formation was performed. As a result, excellent color reproducibility of pale colors was obtained, and good results were obtained.

Example 7 A magnetic toner was obtained in the same manner as in Example 1 except that 200 g of magnetic iron oxide treated with a silane coupling agent (average particle size: 0.25 μm) was used and hydrophobic silica was used. Using this magnetic toner, a commercially available copier OP8582
A surface layer of a fixing device (manufactured by Canon) was remodeled into an FEP having a flexural modulus at 23 ° C. of 6000 kgf / cm ² , and an image was formed. Good results were obtained.

[0166]

According to the present invention, the flexural modulus at 23 ° C. of the surface resin of the pressure contact member of the fixing device is 4000 to 10,000.
When it is in the range of kgf / cm ² , part or all of the wax forms an appropriate film, and the toner is not offset, and can be applied to a clear full-color OHP having excellent offset resistance and excellent transparency. An image forming method can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a heating roller type fixing device.

FIG. 2 is a schematic diagram illustrating an example of a film heating type fixing device.

[Explanation of symbols]

 101 heating roller 2,102 pressure roller T toner P recording material (paper)

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-342225 (JP, A) JP-A-6-130848 (JP, A) JP-A-7-64419 (JP, A) JP-A-7- 64420 (JP, A) JP-A-7-92736 (JP, A) JP-A-7-84407 (JP, A) JP-A-7-77833 (JP, A) JP-A-7-120962 (JP, A) JP-A-7-36301 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/20 101 G03G 9/08 365

Claims (6)

(57) [Claims] 1. An image forming method for fixing an unfixed toner image carried on a recording material to the recording material by a fixing device that heats and presses with a pressing member, wherein the toner is prepared in an aqueous medium. The toner contains at least a binder resin, a colorant, and a wax , and has a weight average molecular weight (Mw) of 400 to 40.
00 or less, and the number average molecular weight (Mn) is 200 or more and 4
000 or less, and the SP value is 7.5 to 10.5.
The flexural modulus at 23 ° C. of the surface resin of the pressure contact member is
When kgf / cm ² , 4000 ≦ A ≦ 10000, and the fixing device does not have an oil application mechanism. 2. The image forming method according to claim 1, wherein the pressing member has at least a repeating unit of tetrafluoroethylene in a main chain. Wherein said pressing member has a repeating unit of at least tetrafluoroethylene in the main chain, images according to claim 1, characterized in that it comprises a fluoroalkoxy group or / and fluoroalkyl groups in the side chain Forming method. Wherein said pressing member is at least having a repeating unit of tetrafluoroethylene, image formation in claim 1 serial <br/> mounting characterized by having a fluoroalkyl group in a side chain in the main chain Method. 5. The image forming method according to claim 3 or 4, wherein the fluoroalkyl group is a 3 methyl fluoride group. 6. The image forming method as in claim 1 serial <br/> placement of the fluorine resin is characterized in that optionally blended according to claims 2 to 5.