JPH09134035A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image excellent in rubbing resistance with a toner for developing an electrostatic charge image capable of exhibiting releasability at low temp., having satisfactory anti-offsetting property, excellent in flowability as powder and not causing blocking phenomenon. SOLUTION: An electrostatic latent image is formed on a latent image retainer and developed with a developer on a developer carrier to form a toner image and this toner image is transferred to the top of a transfer body and fixed by heating. The toner particles of the developer contain modified PE wax obtd. by graft-polymerizing a styrene monomer and/or an unsatd. carboxylic acid monomer on an ethylene homopolymer or a copolymer of ethylene with 3-10C α-olefin obtd. by polymn. in the presence of a metallocene catalyst. In the fixing process, a heating roll 4 obtd. by coating the surface of a roll core 5 with a metal oxide layer 6 is used.

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 for fixing an image by using a dry toner used for developing an electrostatic latent image in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art In electrophotography, when copying, a toner is adhered to an electrostatic latent image formed on a photoconductor using a photoconductive material by a magnetic brush developing method to develop the photoconductor. The above toner image is transferred onto a transfer material such as paper or sheet and then fixed using heat, solvent, pressure or the like to obtain a permanent image.

As a method for fixing a toner image, a heating and melting method is most often used, but this method is roughly classified into a contact type and a non-contact type. In particular, the contact-type heating roll fixing method has been widely used in commercial copying machines, printers, and the like in recent years because it has good thermal efficiency and can perform high-speed fixing. However, even this heating roll fixing system has some drawbacks. For example, it has been pointed out that the amount of energy, that is, the amount of power used, is considerably larger than that of the pressure roll fixing method.

Of course, the strength of a fixed image on a transfer material such as paper is much better in the heating roll fixing method than in the pressure roll fixing method, and the paper is deformed by pressure and wrinkles are generated. But excellent. Therefore, how to reduce the power consumption in the heat fixing method, in other words, how to lower the minimum temperature required for fixing the toner image has been studied.

As a powerful means for achieving this object, a binder resin for a toner having a Tg (glass transition temperature) several tens of degrees lower than that usually used and one having a low molecular weight are used. And the like. However, most of such toners have a fatal drawback that they easily cause caking phenomenon or aggregation during storage or in a copying machine.

As a measure for solving this drawback, it has been attempted to attach very fine colloidal silica, alumina, titania and the like to the surface of toner particles to improve the blocking resistance and fluidity of the toner. This measure does not increase the minimum fixing temperature so much, and the blocking resistance and fluidity are improved to some extent.
At first glance it seems to be an effective means. However,
These fine particles are easily released from the toner particle surface even if they are subjected to heat treatment or the like in order to fuse them to the toner particle surface, and when the photoconductor, particularly the surface is coated with an organic polymer or the like, Was found to have an adverse effect on the photoconductor. That is, when used many times, these fine particles semi-permanently adhere to the surface of the photoreceptor,
This causes the inconvenience of causing image loss. Therefore, this measure cannot be a drastic solution.

Further, when the binder resin as described above is used, the toner adheres to the heating roll and stains the next copy,
There is a possibility that a so-called offset phenomenon may occur. As a means for preventing this, in a conventional fixing device (Japanese Unexamined Patent Publication No. 61-205968, etc.), a heating roll having a surface coated with a fluororesin is used, and silicone oil or the like is applied to the roll surface. A means is provided to make it difficult for the molten toner to adhere to the surface of the heating roll. In this case, the offset phenomenon can be prevented to some extent, but its effect decreases as the temperature of the heating roll increases. Furthermore, in high-speed copying, if the amount of heating heat per unit time is increased to cope with the increase in fixing speed, the offset phenomenon is more likely to occur.

Further, in the heating roll fixing method, a peeling claw is provided on the fixing roll portion to prevent the transfer material, generally paper, from being wound around the roll after passing through the fixing roll.
However, as the speed of copying machines has increased in recent years, the stress applied to this part has increased, which may cause problems such as peeling failure or image loss at the tip of the transfer material due to the nail when peeling. The copied image may be used as a document for further copying, but when the copied image is inserted into the automatic document feeder of the copying machine, the document is rubbed by the paper feed roller of this device,
Image bleeds and stains. In the case of a double-sided original or a multicolor original, the first copy image is fixed and then the second copy is performed, but at this time, the image surface is rubbed by the paper feed roller, causing bleeding or stains on the image. Further, when a plurality of originals that have been stacked and temporarily stored in the copying machine are taken out one by one by the paper feed roller for the second copying, the rear surface of the original and the image surface of the lower original are also transferred. Are rubbed against each other to cause rubbing and smearing on both sides, resulting in deterioration of image quality.

In order to improve these problems, a method of adding low molecular weight polypropylene or polyethylene as a lubricant into the toner has been proposed (Japanese Patent Publication No. 52-33).
No. 04, Japanese Patent Publication No. 52-3305, Japanese Patent Publication No. 57
No. 52574, Japanese Patent Publication No. 58-58664,
JP-A-58-59455 and JP-A-60-15
1650). Toners added with a lubricant disclosed in these publications have some effects in improving offset resistance due to poor releasability from heating rolls, suppression of peeling nail scratches, improvement in rubbing strength of fixed images, etc. The effect is not enough. Furthermore, since the compatibility of these polyolefin-based lubricants and resin components is low, the lubricant forms large domains in the toner, resulting in a problem that the powder fluidity, cohesiveness, etc. of the toner are greatly deteriorated.

As a method for solving these problems, a method of grafting a polyolefin to a resin and making the resin compatible with the resin (Japanese Patent Application Laid-Open Nos. 60-457 and 60-93).
456, JP-A-60-93457, etc.) and a method of dispersing a modified polyolefin in a resin (JP-A-58-63947, JP-A-59-17).
7570, JP-A 60-3644, JP-A 62-14508, JP-A 63-191817, etc.) are known. However, these methods improve the dispersibility of the polyolefin, and the powder fluidity,
Although the deterioration of cohesiveness and the like can be suppressed to some extent, there is a problem that the originally required mold releasing ability improving effect is lost.

Further, in the image fixing method using the heating roll fixing device, when the surface of the heating roll is coated with the fluororesin as described above, there is a problem that the roll surface is scratched at the portion where the peeling claw comes into contact. If scratched, it may induce streaky stains or improper fixing on the copy at the scratched part, so in order to prevent it, in addition to fluororesin coating on the roll surface, a thin coating made of elastic material on the roll core surface Layers are often provided. When such a coating layer is formed, the thermal conductivity of the coating layer is poor, and a long warm-up time (standby time) is required after the device is turned on until the fixing device reaches a usable state. There is a problem of becoming.

Therefore, in order to shorten the warm-up time, the heating roll is composed of a ceramic core, a heating element layer is formed on the surface thereof, and the heating element layer surface is coated with a thin fluororesin. It has been proposed (Japanese Patent Laid-Open No. 61-73980, etc.). When the heating roll according to this method is used, the fixing operation can be performed in a very short waiting time after the energization of the fixing device is started. However, the ceramic score has a problem that it requires a lot of time and effort to manufacture because it is manufactured by molding ceramic into a cylindrical shape and firing it at a high temperature, and it is difficult to process it after firing. doing. Further, even when the surface of the heating roll is coated with a fluororesin and silicone oil is applied, the melted toner tends to push the oil and adhere to the surface of the heating roll, so that the releasing property is relatively good. Even with a fluororesin, there is a problem that the toner cannot be completely prevented from adhering.

Further, a mechanism for retracting the peeling claw member and a mechanism for allowing the peeling claw to come into contact with the heating roll only when peeling the leading edge of the paper are provided, thereby suppressing the occurrence of scratches on the surface of the heating roll. However, the above-mentioned problems cannot be solved completely under the present circumstances.

On the other hand, in order to solve these problems, the heating roll is constructed by using a core of metal or the like, the surface of which is covered with a metal oxide layer to form a smooth surface, and the surface of the heating roll is modified with silicone oil. There has been proposed a method of providing a means for coating (Japanese Patent Application Laid-Open No. 5-107974). According to this method, not only the above problems can be solved to some extent, but also the minimum fixing temperature required for fixing the toner can be lowered without increasing the power consumption due to the high thermal conductivity of the heating roll itself. However, the surface of the heating roll obtained by this method has a lower releasing ability than the surface coated with a fluororesin or the like, and therefore the effect is not sufficient even if the modified silicone oil is applied.

Further, when a wax is added to the toner in order to supplement the releasing effect, polypropylene wax is generally used in many cases in consideration of the balance of powder characteristics and releasing property. There is a problem that the melting point of the system wax exceeds the minimum fixing temperature, and the effect of lowering the minimum fixing temperature of the heating roll cannot be fully utilized.

[0016]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned circumstances in the prior art, and has an object to improve the disadvantages thereof. That is, the object of the present invention is to form an image using a toner for developing an electrostatic charge image, which can exhibit releasing ability at a lower temperature, has good offset resistance, has excellent powder fluidity, and does not cause a blocking phenomenon. To provide a method. Another object of the present invention is to provide an image forming method capable of forming an image having excellent rubbing image strength without being damaged by the peeling claw of the fixing roll portion. Another object of the present invention is to provide an image forming method that can lower the minimum fixing temperature, suppress the occurrence of peeling nail scratches on a heating roll, and shorten the warming-up time without increasing the power consumption.

[0017]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have constructed a heating roll using a core made of metal or the like,
In an image fixing method using a fixing device in which the surface of the roll core is covered with a metal oxide layer to form a smooth surface, a binder resin, a colorant, and a lubricant are essential components, and a specific polymerized in the presence of a metatheron catalyst as a lubricant is used. The inventors have found that the above problems can be solved by using a toner for developing an electrostatic charge image containing a polyethylene wax obtained by graft-modifying a polymer, and have completed the present invention.

That is, according to the present invention, a step of forming an electrostatic latent image on a latent image carrier, and a step of developing the electrostatic latent image with a developer on a developer carrier to form a toner image. In the image forming method having a step of transferring the toner image formed on the latent image holding member onto a transfer member and a fixing step of heating and fixing the toner image, the toner particles of the developer have a metatheron catalyst present. A styrene-based monomer and / or an unsaturated carboxylic acid-based monomer are added to an ethylene homopolymer or an ethylene-based copolymer composed of ethylene and an α-olefin having 3 to 10 carbon atoms obtained by the following polymerization. It contains a polyretylene wax modified by graft polymerization (hereinafter referred to as "modified polyethylene wax"),
In the fixing step, as the heating roll, one obtained by coating the roll core surface with a metal oxide layer is used.

In the present invention, the modified polyethylene wax is obtained by polymerization in the presence of a metacelone catalyst and has a density of 0.95 g / cm ³ or more, an average molecular weight of 800 to 3000, and a molecular weight distribution Mw.
(Weight average molecular weight) / Mn (number average molecular weight) = 1.1-
70 to 95 parts by weight of an ethylene homopolymer or an ethylene copolymer, which is 1.8, and a styrene monomer and /
Alternatively, the melt viscosity at 160 ° C. formed by graft-polymerizing 5 to 30 parts by weight of an acrylic monomer is 1
It is preferably 5 cps to 250 cps and has a penetration of 1 dmm or less. Further, in the heating roll of the present invention, an aluminum oxide layer is formed on the surface of the aluminum core, and the concave portion formed in the aluminum oxide layer is filled with a filling material such as molybdenum sulfide to form a roll surface. A means for forming a smooth surface or the like can be used. The smoothness is preferably one having an average roughness Ra of 1 μm or less.

According to the present invention, since the roll core surface of the heating roll is not covered with a resin or the like as in the conventional case, the constitution as described above causes the heat from the heating source to bring the roll surface to a predetermined temperature. The time until heating can be shortened, and the time required for warming up can be shortened. Further, in the heating roll of the present invention, the metal oxide layer has a very high hardness,
Even when the peeling claw is always in contact with the peeling claw, the surface of the claw is not scratched, and the problem that the copy is contaminated due to scratches on the roll surface can be prevented.

When the toner for developing an electrostatic charge image containing the above-mentioned binder resin and modified polyethylene wax as essential components is used for such a fixing device, the details are unclear, but the modified polyethylene wax is a toner. The toner is dispersed evenly on the surface of the particles, and the wax does not have a very high molecular weight component which is considered to viscoelastically inhibit the stress reducing effect at the time of releasing, and the toner image from the heating roll is controlled by controlling each physical property. As a result, the toner image can be easily peeled from the surface of the heating roll having a low mold release ability, and the stress at the time of mold release is reduced, and as described above. Since the heating roll is less likely to be damaged by the peeling claw or the like, it is possible to achieve both a long life of the heating roll and high releasability.

Further, by controlling the compatible component of the modified polyethylene wax with the binder resin, the powder flow of the toner can be achieved without impairing the rubbing image strength of the modified polyethylene wax itself and the effect of suppressing peeling nail scratches. It is possible to improve the property and reduce the blocking property and the caking resistance. Furthermore, for the above reasons,
It is possible to use low-molecular-weight polyethylene wax that was previously unusable, and the melting point of the wax can follow the lowering effect of the heating roller on the lowest fixing temperature. Will be demonstrated.

[0023]

Embodiments of the present invention will be described below in detail. First, the developer used in the present invention will be described. The toner in the developer of the present invention contains a lubricant, and the lubricant used in the present invention is an ethylene homopolymer obtained by polymerization in the presence of a metacelone catalyst or ethylene and 3 to 10 carbon atoms. Which is obtained by graft-modifying an ethylene-based copolymer comprising an α-olefin, wherein the ethylene homopolymer or the ethylene-based copolymer is added with a styrene-based monomer and / or an unsaturated carboxylic acid-based monomer. It is formed by graft polymerization.

The metallocene catalyst used for producing the ethylene homopolymer or the ethylene copolymer is
It can be used without any particular limitation. For example, (A) a compound of a transition metal selected from the group consisting of groups IVb, Vb and VIb of the periodic table (hereinafter,
It is called "transition metal compound". ) And (B) a cocatalyst in combination are exemplified. Examples of the compound of the above transition metal include those represented by the following formula (1). ML _x (1)

In the above formula (1), M is IVb, Vb and VI.
represents a transition metal atom selected from group b, zirconium,
Examples include titanium and hafnium. x is the valence of the transition metal and represents the number of L. L represents a ligand or group that coordinates to a transition metal, at least one L is a ligand having a cyclopentadienyl skeleton such as cyclopentadienyl, indenyl, and other L is Carbon number 1
To 12 aliphatic, araliphatic or aromatic hydrocarbon groups, alkoxy groups, aryloxy groups, trialkylsilyl groups, SO ₃ R ¹ (wherein R ¹ is a carbon which may have a substituent such as halogen) A hydrocarbon group of the number 1 to 8),
It is one kind of group or atom selected from the group consisting of a halogen atom and a hydrogen atom. Furthermore, when the compound represented by the general formula (1) contains two or more ligands having a cyclopentadienyl skeleton, the ligands having two cyclopentadienyl skeletons are ethylene and propylene. And the like, or a substituted alkylene group such as isopropylidene or diphenylmethylene, a silylene group, or a substituted silylene group such as a dimethylsilylene group or a diphenylsilylene group.

Examples of such compounds include bis (cyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, bis (ethylcyclopentadienyl) zirconium dichloride, bis (n-propylcyclohexyl). Pentadienyl) zirconium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride, bis (n-
Hexylcyclopentadienyl) zirconium dichloride, bis (methyl-n-propylcyclopentadienyl) zirconium dichloride, bis (methyl-n-butylcyclopentadienyl) zirconium dichloride, bis (dimethyl-n-butylcyclopentadienyl) ) Zirconium dichloride, bis (n-butylcyclopentadienyl) zirconium dibromide, bis (n-butylcyclopentadienyl) zirconium methoxychloride,
Bis (n-butylcyclopentadienyl) zirconium ethoxy chloride, bis (n-butylcyclopentadienyl) zirconium butoxycyclolide, bis (n-butylcyclopentadienyl) zirconium ethoxide, bis (n-butylcyclopentadiene) (Enyl) zirconium methyl chloride, bis (n-butylcyclopentadienyl) dimethyl zirconium, bis (n-butylcyclopentadienyl) zirconium benzyl chloride, bis (n-butylcyclopentadienyl) dibenzyl zirconium, bis (n -Butylcyclopentadienyl) zirconium phenyl chloride, bis (n-butylcyclopentadienyl) zirconium hydride chloride, ethylenebis (indenyl) dimethylzirconium, ethylenebis (indenyl) Diethylzirconium, ethylenebis (indenyl) diphenylzirconium, ethylenebis (indenyl) methylzirconium monochloride, ethylenebis (indenyl) ethylzirconium monochloride, ethylenebis (indenyl) methylzirconium monobromide, ethylenebis (indenyl) zirconium dichloride, ethylene Bis (indenyl) zirconium dibromide, ethylene bis {1- (4,5,5
6,7-Tetrahydroindenyl)} dimethylzirconium, ethylenebis {1- (4,5,6,7-tetrahydroindenyl)} methylzirconium monochloride,
Ethylene bis {1- (4,5,6,7-tetrahydroindenyl)} zirconium dichloride, ethylene bis {1- (4,5,6,7-tetrahydroindenyl)}
Zirconium dibromide, ethylenebis {1- (4-methylindenyl)} zirconium dichloride, ethylenebis {1- (5-methylindenyl)} zirconium dichloride, ethylenebis {1- (6-methylindenyl)} zirconium Dichloride, ethylene bis {1-
(7-methylindenyl)} zirconium dichloride,
Ethylenebis {1- (5-methoxyindenyl)} zirconium dichloride, ethylenebis {1- (2,3-dimethylindenyl)} zirconium dichloride, ethylenebis {1- (4,7-dimethylindenyl)} zirconium Dichloride, ethylenebis {1- (4,7-dimethoxyindenyl)} zirconium dichloride, isopropylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-2,7-di-t-butyl) Fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-methylcyclopentadienyl) zirconium dichloride, dimethylsilylene bis (cyclopentadienyl) zirconium dichloride, dimethylsilylene bis (methylcyclo) N-dienyl) zirconium dichloride, dimethylsilylenebis (dimethylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, diphenylsilylenebis (indenyl) zirconium dichloride, etc. Can be given. In addition,
In the above examples, the di-substituted cyclopentadienyl ring includes 1,2- and 1,3-substituted compounds, and the tri-substituted compound is 1,2,3- and 1,2,4-substituted compounds. Including the body. In the present invention, the transition metal compound in which the zirconium metal in the above zirconium compound is replaced with titanium metal or hafnium metal can be similarly used.

As the co-catalyst (B), any conventionally known co-catalyst can be used without particular limitation. For example, the compound (B-2) which reacts with the aluminoxane (B-1) or the transition metal compound (A) to form an ionic complex can be mentioned.

Specific examples of the aluminoxane (B-1) include organic aluminum compounds represented by the following general formula (2) or (3).

Embedded image (In the formula, R ² represents a hydrocarbon group, and m represents an integer of 2 or more.)

In the above aluminoxane, R ² is methyl group, ethyl group, propyl group, n-butyl group, iso
-Butyl group, phenyl group, phenylmethyl group and the like are exemplified, and methyl group, ethyl group and iso-butyl group are preferable. m is an integer of 2 or more, preferably 3 to 50,
Particularly, it is an integer of 3 to 40.

The aluminoxane is added to (1) a compound containing adsorbed water or a salt containing water of crystallization, for example, in a hydrocarbon medium suspension of magnesium hydrate, copper sulfate hydrate, or the like, to give a trioxane. A method of reacting an organoaluminum compound such as alkylaluminum to recover it as a hydrocarbon solution, (2) by directly acting water, ice, or steam on the organoaluminum compound such as trialkylaluminum in a medium such as benzene or toluene. There is a method of recovering as a hydrocarbon solution, and the organic aluminum compound used is trimethylaluminum, triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-aluminum.
Examples include sec-butylaluminum, tri-tert-butylaluminum, triisopentylaluminum and the like.

The compound (B-2) which reacts with the transition metal compound (A) to form an ionic complex is, for example, a compound composed of a cation and an anion in which a plurality of groups are bound to an element, particularly Coordination complex compounds can be mentioned as preferable ones. Such compounds include trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tri (n-butyl) ammonium tetraphenylborate, trimethylammonium tetra (pentafluorophenyl) borate, triethylammonium tetra (pentafluorophenyl) borate, Tetra (pentafluorophenyl) borate tri (n-
Butyl) ammonium, triethylammonium hexafluoroarsenate, ferrocenium tetraphenylborate,
Triphenyl tetraphenyl borate, ferrocenium tetra (pentafluorophenyl) borate, methyl ferrocenium tetra (pentafluorophenyl) borate, decamethyl ferrocenium tetra (pentafluorophenyl) borate,
Silver tetra (pentafluorophenyl) borate, trityl tetra (pentafluorophenyl) borate, silver tetrafluoroborate, silver hexafluorophosphate, silver hexafluoroarsenate, silver perchlorate, silver hexafluoroantimonate, silver trifluoroacetate , Silver trifluorometasulfonate, tetra (pentafluorophenyl) borate (N-benzyl-
2-cyanopyridinium), tetra (pentafluorophenyl) borate (N-benzyl-3-cyanopyridinium), tetra (pentafluorophenyl) borate (N-benzyl-4-cyanopyridinium), tetra (pentafluorophenyl) borate ( N-methyl-2-cyanopyridinium), tetra (pentafluorophenyl) boric acid (N
-Methyl-3-cyanopyridinium), tetra (pentafluorophenyl) borate (N-methyl-4-cyanopyridinium), trimethylammonium tetra (pentafluorophenyl) borate, trimethyl tetra (pentafluorophenyl) borate (m-trifluoro) Methylphenyl) ammonium, tetra (pentafluorophenyl)
Examples thereof include benzylpyridinium borate.

If necessary, an organoaluminum compound (C) may be used together with these promoters (B). As such an organoaluminum compound, a compound represented by the following general formula (4) can be exemplified. R ¹ _n AlX _3-n (4) (In the formula, R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms;
Represents a halogen atom or a hydrogen atom, and n is an integer of 1 to 3. )

In the above general formula (4), R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, for example, an alkyl group, a cycloalkyl group or an aryl group, specifically, a methyl group, an ethyl group, Examples thereof include n-propyl group, iso-propyl group, iso-butyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group and tolyl group. As such an organoaluminum compound, trimethylaluminum,
Trialkylaluminums such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum; alkenylaluminums such as isoprenylaluminum; dimethylaluminum chloride, diethylaluminium chloride, diisopropylaluminum chloride, diisobutyl. Dialkyl aluminum halides such as aluminum chloride and dimethyl aluminum bromide; alkyl aluminum sesquihalides such as methyl aluminum sesquichloride, ethyl aluminum sesquichloride, isopropyl aluminum sesquichloride, butyl aluminum sesquichloride and ethyl aluminum sesquibromide; methyl aluminum dichloride De, ethylaluminum dichloride, isopropyl aluminum dichloride, alkyl aluminum dihalides such as ethyl aluminum dibromide; diethylaluminum hydride, compounds such as alkyl aluminum hydride such as diisobutyl aluminum hydride are used.

The polymerization reaction of ethylene in the present invention is
A metallocene-based catalyst comprising the above transition metal compound (A) and the co-catalyst (B) and, if necessary, the organoaluminum compound (C) represented by the above general formula (4) is used. The polymerization reaction is carried out in a hydrocarbon medium.
Specific examples of the hydrocarbon medium include butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, octadecane and other aliphatic hydrocarbons, cyclopentane, methylcyclopentane, cyclohexane, cyclooctane and other alicyclic rings. In addition to group hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene, petroleum fractions such as gasoline, kerosene, and light oil, olefin as a raw material also serves as a hydrocarbon medium. Of these hydrocarbon media, aromatic hydrocarbons are preferred.

The ratio of the above-mentioned transition metal compound used in carrying out the polymerization reaction by the liquid phase polymerization method is usually 10 ^-8 to 10 ^-2 gram atom / liter as the concentration of the transition metal atom in the polymerization reaction system. It is preferably in the range of 10 ⁻⁷ to 10 ⁻³ gram atom / liter. The aluminoxane content is usually in the range of 10 ^-4 to 10 ^-1 gram atom / liter, preferably 10 ^-3 to 10 ^-2 gram atom / liter, as the concentration of aluminum atom in the polymerization reaction system. Is. The ratio of aluminum atom to transition metal atom in the polymerization reaction system is usually 4 to 10 ⁷ ,
It is preferably in the range of 10 to 10 ⁶ .

In the present invention, the molecular weight of ethylene homopolymer or ethylene copolymer is controlled by adjusting hydrogen and / or
Alternatively, it can be carried out depending on the polymerization temperature. The temperature during the polymerization reaction is usually 20 ° C or higher, particularly preferably 50 ° C to 230 ° C. The amount of hydrogen supplied to the polymerization reaction is usually 0.01 as a molar ratio of hydrogen to ethylene.
It is in the range of 4 to 4, preferably 0.05 to 2.

In the present invention, an ethylene homopolymer obtained by polymerization in the presence of these metacelone catalysts or an ethylene copolymer composed of ethylene and an α-olefin having 3 to 10 carbon atoms is used. The intrinsic viscosity [η] measured in decalin at 135 ° C is preferably 0.4d.
1 / g or less, particularly preferably 0.005 without 0.35d
1 / g. In the case of a copolymer, the proportion of ethylene in the constituent monomers is usually 80 mol% or more, preferably 85 mol% or more.

Further, the ethylene homopolymer or ethylene copolymer thus obtained has a viscosity average molecular weight in the range of 800 to 3000 and a density of 0.95 g / c.
It is more preferable that it is m ³ or more and the penetration is 2 dmm or less, particularly 1 dmm or less. Polyethylene in this range
Due to its high density and linearity of the molecule, it has self-lubricating properties,
Therefore, it is possible to reduce the damage due to the abrasion of the surface of the fixed image and prevent the fixed image from being rubbed, smeared, or the like. That is, after passing through the heating roll, a film having lubricity is formed on the surface of the fixed image, and the lubrication effect is sufficiently exhibited.

The molecular weight distribution (Mw) determined by gel permeation chromatography (hereinafter simply referred to as GPC) of the above ethylene homopolymer or ethylene copolymer (hereinafter simply referred to as polyethylene wax).
/ Mn) is usually preferably 1.1 to 1.8, more preferably 1.5 or less.

When the molecular weight distribution Mw / Mn is within this range, it is possible to reduce the high molecular weight component and the low molecular weight component in the polyethylene wax within the above-mentioned viscosity average molecular weight range. This eliminates the blocking effect of low molecular weight components that start melting at low temperatures, the deterioration of powder fluidity at room temperature, and the reduction of peel nail damage suppression effect due to the partial increase in melt viscosity of high molecular weight components. It is possible to It also has a great influence on the melting behavior of the polyethylene wax itself. In general, polyethylene wax maintains a completely solid state under normal conditions, and when it passes through the fixing roll, it completely melts in the vicinity of the set temperature of the fixing roll during its extremely short passage time to exert its effect. Is required. When the molecular weight distribution is controlled within the above range, the melting temperature range for finishing the melting can be narrowed as compared with the wax which is usually used. As a result, the amount of wax that contributes to release (the amount of wax that melts at the set temperature of the fixing roll)
The efficiency is improved from the viewpoint of the expression effect.

The metallocene catalyst can obtain a polymer having a narrower molecular weight distribution than conventional catalyst systems. Therefore, it is not necessary to narrow the molecular weight distribution by the method of distillation, crystallization, and solvent washing, and even when necessary, it can be efficiently carried out.

The molecular weight distribution (Mw / Mn) of the polyethylene wax used in the present invention is G manufactured by Waters Corporation.
It is a value measured using PC150C at a temperature of 140 ° C., solvent o-dichlorobenzene, and a measurement flow rate of 1.0 ml / min at a concentration of 0.1 wt%. In calculating the molecular weight of the sample, the viscosity equation of polyethylene was used. As a column
Tosoh GMH-HT (60 cm) and GMH-HTL
(60 cm) connected was used. Further, the penetration is in accordance with JIS K2207, the density is in accordance with JIS K6760, and the melt viscosity is a value measured by Brookfields viscometer after heating and melting the sample at 160 ° C.

The polyethylene wax produced by the above method is further degassed under vacuum at a temperature equal to or higher than the melting point, or dissolved in a solvent such as hexane or acetone to remove the low molecular weight portion, or the polyethylene wax is completely dissolved in the solvent. After that, a method of removing the high molecular weight portion by precipitating at a specific temperature may be used together.

In addition, to the above polyethylene wax,
The graft modification ratio of the styrene-based monomer or unsaturated carboxylic acid-based monomer is preferably 5 to 30 parts by weight when the total weight is 100 parts. Within this range,
There is no adverse effect on powder fluidity, blocking property, caking resistance, etc. due to large domains, release effect due to excessive dispersion of lubricant in toner, reduction in rubbing resistance, etc. Can be shown.

Examples of the styrenic monomer used for the graft polymerization in the present invention include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene,
4-methylstyrene, 2,5-dimethylstyrene, 3,
4-dimethylstyrene, 2,4,6-trimethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4--
Butyl styrene, 4-sec-butyl styrene, 4-t
ert-butyl styrene, 4-hexyl styrene, 4-
Nonylstyrene, 4-octylstyrene, 4-phenylstyrene, 4-decylstyrene, 4-dodecylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 3,4-dichlorostyrene, 2-methoxystyrene, 4-methoxystyrene, 4-ethoxystyrene, etc. can be mentioned.

As the unsaturated carboxylic acid type monomer used for the graft polymerization, methyl acrylate, ethyl acrylate, butyl acrylate, sec-butyl acrylate, isobutyl acrylate, propyl acrylate, Isopropyl acrylate, octyl acrylate, dodecyl acrylate, stearyl acrylate, hexyl acrylate, isohexyl acrylate, phenyl acrylate, 2-chlorophenyl acrylate, diethylaminoethyl acrylate, 3-methoxybutyl acrylate, diethylene glycol ethoxy acrylate rate,
Acrylic esters such as 2,2,2-trifluoroethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate, propyl methacrylate,
Isopropyl methacrylate, octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, hexyl methacrylate, decyl methacrylate, phenyl methacrylate, 2-chlorophenyl methacrylate, diethylaminoethyl methacrylate, 2-ethylhexyl methacrylate, 2,2 methacrylate , 2-trifluoroethyl and other methacrylic acid esters, ethyl maleate, propyl maleate, butyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate and other maleic acid esters, ethyl fumarate, butyl fumarate And fumaric acid esters such as dibutyl fumarate, and itaconic acid esters such as ethyl itaconate, diethyl itaconate, and butyl itaconate.

The styrene-based monomer or unsaturated carboxylic acid-based monomer graft-polymerized on the polyethylene wax has been exemplified above, but the present invention is not limited thereto. As a method of modifying the above-mentioned monomer into polyethylene wax, various known methods can be adopted. For example, a method in which a polyethylene wax and a styrene-based monomer or an unsaturated carboxylic acid-based monomer are heated and melt-mixed in the presence of a radical initiator and reacted, can be used. In that case, the reaction temperature is 125 to 325.
The temperature range is preferably in the range of ° C, and the radical initiator to be used includes peroxides such as benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and azo compounds such as azobisisobutyronitrile. Can be given.

The melt viscosity of the modified polyethylene wax is preferably 15 to 250 cps at 160 ° C. In this range, the cohesive strength of the fixed image immediately after passing through the heating roll and the melt viscosity of the image surface are appropriately controlled, image scraping by the peeling nail, defective release, and peeling nail scratches due to excessive stress during releasing are generated. It is possible to suppress. In particular, when the polyethylene wax obtained by the above method has the above-mentioned viscosity average molecular weight range, the polyethylene wax using the metallocene-based catalyst as described above has the advantages of maintaining the balance with other wax physical properties. There is an advantage that it is easy to control so as to exhibit a desired melt viscosity.

The modified polyethylene wax preferably has a penetration of 2 dmm or less, particularly 1 dmm or less. In this range, the modified polyethylene wax has a self-lubricating property due to its high density and linearity of the molecule, which reduces the damage due to abrasion of the surface of the fixed image, rubbing stains, bleeding, etc. on the fixed image. Can be prevented. That is, after passing through the heating roll, a film having lubricity is formed on the surface of the fixed image, and the lubrication effect is sufficiently exhibited.

The amount of the modified polyethylene wax added to the toner is preferably in the range of 1 to 20% by weight, more preferably 3 to 10% by weight, based on the weight of the toner.

The toner particles to which the modified polyethylene wax is added are not particularly limited as long as they are publicly known toners containing a binder resin and a colorant as main constituent components. The binder resin used for the toner particles is styrenes such as styrene, chlorostyrene, vinyl styrene, vinyl acetate,
Vinyl esters such as vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid Butyl, α-methylene aliphatic monocarboxylic acid esters such as dodecyl methacrylate, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl butyl ether, homopolymers or copolymers of monomers such as vinyl methyl ketone, Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide and the like can be exemplified, and in particular, as a typical binder resin, polystyrene,
Styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, styrene-alkyl acrylate copolymer, etc. However, the present invention is not limited to these.

Dyes and pigments are used as the colorant which is another main constituent of the toner particles, and examples thereof include carbon black, nigrosine dye, aniline blue, calcyl blue, chrome yellow and ultramarine. Blue, DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue,
Malachite Green Oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 48: 1,
C. I. Pigment Red 122, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Yellow 97,
C. I. Pigment Yellow 12, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 3
Further, magnetic materials such as magnetite and ferrite can be exemplified as typical ones.

The colorant is not limited to the above-mentioned ones, and if necessary, known additives such as a charge control agent may be added, and a fluidity improver including colloidal silica fine particles. Other inorganic compound fine particles may be externally added. The developer used in the present invention contains the above-mentioned toner particles, but it may be a two-component toner, a one-component toner containing a magnetic material or a capsule toner.

Next, the image forming method of the present invention using the above developer will be described. The image forming method of the present invention,
Forming an electrostatic latent image on the latent image holding member, developing the electrostatic latent image with a developer on a developer bearing member to form a toner image, forming on the latent image holding member The method includes a step of transferring the formed toner image onto a transfer body and a fixing step of heating and fixing the toner image, and can be appropriately used according to a dry process, but in general, electrophotography, It can be suitably applied to electrostatic recording and the like.

In the step of forming an electrostatic latent image on the latent image holding member, the latent image holding member may be a Se-based photosensitive member, an organic photosensitive member, an amorphous silicon-based photosensitive member, or the surface thereof as required. Overcoat, etc.
Conventionally known ones can be used. The latent image can be formed by a known method.

In the developing step, the above-mentioned developer is carried in a thin layer by the layer regulating member on the developer carrying member which is in contact with the latent image holding member in the developing section or which is arranged at a constant interval. The image is conveyed to the developing section and developed. As a result, a toner image is formed on the latent image carrier.

The toner image formed on the latent image holding member is then transferred onto a transfer member such as paper. As the transfer means,
A contact type in which a roll transfer device is pressed against the latent image carrier,
Alternatively, any non-contact type using a corotron may be used.

The transferred toner image is heat-fixed in the fixing step. In the fixing device used for heat-fixing in the present invention, a heating roll in which the surface of the roll core is covered with a metal oxide layer to form a smooth surface is used. To be done. FIG.
FIG. 1 is a sectional view of an example of the fixing device used in the present invention. In FIG. 1, the fixing device 1 is configured by arranging a heating roll 4 accommodating a heating source 7 such as a halogen lamp and a pressure roll 3 so as to face each other, as in the case of a conventional heating roll type device. ing. Of the two fixing roll members, the pressure roll 3 is a metal core member whose surface is covered with an elastic member with a thickness of several mm. The pressure roll 3 faces the heating roll. It is provided so as to press with a predetermined nip pressure. Also, for the heating roll,
A peeling claw 2 for peeling the paper is arranged to perform the action of peeling the paper after fixing is completed.

In the above fixing device, the heating roll 4
Is a metal roll core 5 having a surface coating layer 6 made of a metal oxide formed on the surface thereof.
As a structure, a pipe-shaped member having a thickness of several mm is used, and the surface coating layer 6 is provided on the surface thereof with a thickness of several μm to several tens of μm. The surface coating layer 6 may be formed by oxidizing the metal forming the roll core. For example, when the roll core 5 is made of iron, an iron oxide film is formed as the surface coating layer. What was formed can be used. The surface coating layer can also be formed by coating a metal oxide different from the metal forming the roll core. further,
It is also possible to use a roll core formed of a plastic material or the like as the roll core, and form a surface coating layer on the surface of the roll core made of plastic using a means for thinly coating the metal oxide.

In the fixing device of the present invention configured as described above, for example, when the roll core is made of aluminum, the heating roll 8 is, as shown in FIG.
On the surface of the roll core 9 made of metallic aluminum,
The structure has the aluminum oxide film 10 formed as the surface coating layer. The aluminum oxide film 10
Can be easily formed by performing an alumite treatment. Since the hardness of the aluminum oxide coating is extremely large, even if the peeling claw comes into contact with the roll surface, the coating will not be scraped off, and the problem as in the case of the fluororesin coating may occur. Absent. Further, when the peeling claw is made of plastic or the like, the peeling claw is only worn, and the heating roll main body is prevented from being scratched.

In addition to the above case in which the roll core is made of aluminum, a roll core made of aluminum or another metal material is used, and the surface of the roll core is coated with a metal oxide and then the surface is It may be treated with molybdenum sulfide or fluororesin. That is, as shown in FIG. 3, the heating roll 11 forms the metal oxide coating 13 on the surface of the metal roll core 12 with a predetermined thickness, but the surface of the oxide coating has irregularities. A large number of very small recesses 14 are formed. However, since the oxide film of the metal is extremely hard, removing it by polishing would result in a very high cost. Therefore, in the present invention, it is preferable to fill the recess 14 of the oxide film 13 with a filler 15 such as molybdenum sulfide or fluororesin to smooth the roll surface.

When molybdenum sulfide is filled in the concave portion, it is not necessary to maintain the roll surface temperature at 200 ° C. or lower as in the case of fluororesin, and the heating temperature of the roll member can be well controlled. It can be carried out. Also,
Since the molybdenum sulfide is also used as a lubricant, it is possible to reduce the frictional action with respect to the member pressed against the roll surface, and for example, even when pressing the peeling claw, It is possible to reduce the abrasion effect on the claw members, and it is possible to improve the durability of both members.

In the present invention, the metal oxide coating formed on the surface of the roll core may be a ceramic coating. For example, even when the roll core is made of plastic, a coating material mainly composed of ceramics (for example, “ceramica” ... trade name) is used on the surface of the roll core, and after the material is thinly coated, heat treatment is performed. A ceramic coating can be formed on the surface of the roll core. Further, also in the roll member as shown in FIG. 3, by applying a filler such as molybdenum sulfide to the concave portion of the aluminum oxide film, and then applying a coating material thinly on the surface and firing, A ceramic coating can be formed.

As the coating material, alumina-
A silica-based material can be used. It is also possible to use a mixture of the above materials as a main material and fillers of various metal oxides. For example, as the filler, NiO, MgO, ZrO ₂ , Fe ₂ O ₃ , Ti
O ₂ , SnO ₂ (tin oxide), ZnO (lead oxide) can be used. When the above coating material is used, the roll core is dipped in a solution of the coating material and the roll core
A few μm to a few 1 by baking by applying heat of about ℃
A ceramic coating with a thickness of 00 μm can be formed. Therefore, as described above, when used as a means for forming a ceramic surface coating on the roll member surface,
The roll core can be made of any material having good workability, such as metal or plastic, and an oxide film having high hardness can be formed on the surface of the roll core.

The oxide coating formed on the surface of the roll core is formed of an oxide of the same material as that of the roll core. In addition, when the metal oxide is sprayed, in addition to aluminum oxide, iron or It is also possible to use oxides of titanium, magnesium, calcium, nickel, copper, etc., or glass, etc. Furthermore, when the roll core is made of aluminum, iron, or the like, it is possible to form a surface coating with the oxide, but also in the case of titanium, magnesium, ceramics, nickel, copper, or the like. The surface coating can be formed by the oxide of the material forming the roll core.

When the roll core is formed by using the above-mentioned materials, the surface of the heating roll is not only very hard but also has good thermal conductivity. Therefore, in the heating roll according to the present invention, in addition to disposing the heating source inside the roll core, the external heating source 17 is disposed outside the heating roll 4 as shown in FIG. It can also be configured to provide a heating effect. Further, since the surface of the heating roll is very hard, the peeling claw is not made of plastic, and the needle-like peeling claw 18 made of metal is arranged as shown in FIG. The tip of the peeling claw 18 may be constantly pressed against the surface of the heating roll 4. In FIG. 4 and FIG. 5, 16 is an oil application device, and other reference numerals have the same meanings as described above.

In the fixing device of the present invention, modified silicone oil may be applied on the heating roll. Examples of the silicone oil used in this case include mercapto-modified silicone oil and commercially available silicone oil such as amino-modified silicone oil. In addition, any modified silicone oil can be used as long as it can chemically bond with the metal oxide and exhibit an effect of not attaching the toner to the roll surface. A modified silicone oil application device is shown in FIG.
As shown in FIG. 5 and FIG. 5, in addition to the oil applying device 16 using a web, it is possible to use an oil applying device having any other arbitrary configuration such as an applying device using a roll.

[0068]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following description, "part" means "part by weight". (Production of Polyethylene Wax Using Metallocene Catalyst) Production Example A Using a continuous polymerization reactor, 200 liters / hr of purified hexane and 0.4 mol / mol of methylaluminoxane (manufactured by Tosoh Akzo) in terms of aluminum atom / hr, trimethylaluminum 0.2 mol / hr and bis (n
-Butylcyclopentadienyl) zirconium dichloride was continuously supplied at a rate of 2 mmol / hr in terms of zirconium atom, and hydrogen and ethylene ratio (H ₂ / C ₂ H ₄ ) was 0 in the gas phase in the polymerization reactor. .40, total pressure 30
Ethylene and hydrogen were continuously supplied so as to obtain kg / cm ² G, polymerization temperature 140 ° C., atmospheric pressure, residence time 0.5
Polymerization was carried out under conditions such that the polymer concentration was 90 g / liter for an hour. To 1 liter of the obtained polymer solution,
After adding 5 liters of methanol to precipitate the polymer, the polymer was recovered by filtration and dried to obtain a polymer having the following physical properties. [Η]: 0.08 dl / g, molecular weight distribution Mw / Mn:
1.3, viscosity average molecular weight: 1130, density: 0.96 g
/ Cm ³ , melt viscosity at 160 ° C .: 12.0 cps.

Production Example B Same as Production Example A except that in the polymerization reaction of Production Example A, the hydrogen and ethylene ratio (H ₂ / C ₂ H ₄ ) in the gas phase in the polymerization reactor was changed to 0.50. The polymerization reaction was carried out. The physical properties of the obtained polymer were as follows. [Η]: 0.06 dl / g, molecular weight distribution Mw / Mn:
1.2, viscosity average molecular weight: 890, density: 0.96 g /
cm ³ , melt viscosity at 160 ° C .: 7.7 cps.

(Production Examples of Various Graft-Modified Polyethylene Waxes) Production Example 1 Polyethylene Wax Production Example A Using Metatheron Catalyst
Polyethylene wax ([η]: 0.08 dl / g,
Molecular weight distribution Mw / Mn: 1.3, viscosity average molecular weight: 11
30, density: 0.96 g / cm ³ , melt viscosity at 160 ° C .: 12.0 cps) 1000 g, melted at 160 ° C.,
250 g of styrene and 21 g of di-tert-butyl peroxide were added dropwise via separate conduits over 4 hours. After the dropping was completed, the reaction was further continued at 160 ° C for 1 hour, and then degassed under a vacuum of 30 mmHg for 1 hour to remove volatile matter, and a modified polyethylene wax (penetration: 1 dmm or less, melting at 160 ° C) was performed. Viscosity: 23.7 cps) was obtained.

Production Example 2 Polyethylene Wax Production Example B Using Metatheron Catalyst
Polyethylene wax ([η]: 0.06 dl / g,
Molecular weight distribution Mw / Mn: 1.2, viscosity average molecular weight: 89
0, density: 0.96 g / cm ³ , melt viscosity at 160 ° C .: 7,000 cps) were used in the same manner as in Production Example 1 except that 1000 g of modified polyethylene wax (penetration:
Melt viscosity at 160 ° C. of 1 dmm or less: 17.0 cp
s) was obtained.

Production Example 3 A modified polyethylene wax (penetration: was obtained in the same manner as in Production Example 1 except that a mixture of 125 g of styrene and 125 g of dibutyl fumarate was used instead of 250 g of styrene.
Melt viscosity at 160 ° C. under 1 dmm: 18.0 cp
s) was obtained. Production Example 4 In the same manner as in Production Example 1 except that a mixture of 125 g of styrene and 125 g of butyl methacrylate was used instead of 250 g of styrene, modified polyethylene wax (penetration: 1 dmm or less, melt viscosity at 160 ° C .: 20.0c
ps) was obtained.

Production Example 5 Polyethylene wax (viscosity average molecular weight: 1070, molecular weight distribution: Mw / Mn: 2.61, density: 0.97 g /
cm ³ , melt viscosity at 160 ° C .: 85.0 cps) 10
Modified polyethylene wax (penetration: 1 dmm or less, 160 ° C.) in the same manner as in Production Example 1 except that 100 g was used.
Melt viscosity at 210.0 cps) was obtained. Production Example 6 Instead of 250 g of styrene, 20 g of styrene, di-t
except that 1.7 g of ert-butyl peroxide was used,
In the same manner as in Production Example 1, modified polyethylene wax (penetration: 1 dmm or less, melt viscosity at 160 ° C .: 12.0)
cps). Production Example 7 In the same manner as in Production Example 1 except that a mixture of 125 g of styrene and 540 of dibutyl fumarate was used instead of 250 g of styrene, a modified polyethylene wax (penetration:
2dmm, melt viscosity at 160 ° C: 130.0 cps)
I got

Production Example 8 Polypropylene wax (viscosity average molecular weight: 3000,
Molecular weight distribution: Mw / Mn: 2.75, density: 0.89 g
/ Cm ³ , melt viscosity at 160 ° C .: 70.0 cps) 1
Modified polypropylene wax (penetration: 1 dmm, 180 ° C.) in the same manner as in Production Example 1 except that 000 g was used.
Melt viscosity at 250.0 cps) was obtained.

Example 1 (Preparation of Toner) Styrene-Butyl Methacrylate Copolymer (85/15) 100 Parts (Mw = 1.8 × 10 ⁵ ) Carbon Black (R330, Cabot Co.) 10 Parts Charge Control Agent (P-51, manufactured by Orient Chemical Industry Co., Ltd.) 2 parts Modified polyethylene wax shown in Production Example 1 5 parts The above components are melt-kneaded in a Banbury mixer, cooled and then finely pulverized by a jet mill, and classified by a classifier, Toner particles having an average particle diameter of 10 μm were obtained. (Preparation of Carrier) A ferrite core having a particle size of 85 μm was used. (Preparation of Developer) A developer composition was prepared by mixing 3 parts of the toner and 97 parts of the carrier.

An image was formed using the above developer.
The details of the evaluation conditions are as described below. The heating rolls used were as follows. (Heating Roll) An aluminum core was used as the roll core of the heating roll, and a roll provided with a 20 μm aluminum oxide layer as the surface coating layer was used. Further, molybdenum sulfide was filled in the concave portion. Surface roughness (Ra) is 0.2
μm.

Example 2 A developer composition was obtained in the same manner as in Example 1 except that the modified polyethylene wax shown in Production Example 2 was used as the lubricant. And it evaluated similarly. Example 3 A developer composition was obtained in the same manner as in Example 1, except that the modified polyethylene wax shown in Production Example 3 was used as a lubricant. And it evaluated similarly. Example 4 A developer composition was obtained in the same manner as in Example 1, except that the modified polyethylene wax shown in Production Example 4 was used as a lubricant. And it evaluated similarly.

Comparative Example 1 Polyethylene wax ([η]: 0.13d as a lubricant)
1 / g, molecular weight distribution Mw / Mn: 2.61, viscosity average molecular weight: 2000, density: 0.97 g / cm ³ , 160 ° C.
A melt composition of 55.0 cps) was used, and a developer composition was obtained in the same manner as in Example 1 except that an aluminum core coated with a fluororesin was used as a heating roll. And it evaluated similarly. Comparative Example 2 Polypropylene wax as a lubricant (viscosity average molecular weight:
3000, molecular weight distribution Mw / Mn: 2.75, density:
0.89 g / cm ³ , melt viscosity at 160 ° C .: 70.0
A developer composition was obtained in the same manner as in Example 1 except that cps) was used. And it evaluated similarly.

Comparative Example 3 A developer composition was obtained in the same manner as in Example 1 except that the modified polyethylene wax shown in Production Example 5 was used as the lubricant. And it evaluated similarly. Comparative Example 4 A developer composition was obtained in the same manner as in Example 1 except that the modified polyethylene wax shown in Production Example 6 was used as the lubricant. And it evaluated similarly. Comparative Example 5 A developer composition was obtained in the same manner as in Example 1 except that the modified polyethylene wax shown in Production Example 7 was used as the lubricant. And it evaluated similarly. Comparative Example 6 A developer composition was obtained in the same manner as in Example 1 except that the modified polypropylene wax shown in Production Example 8 was used as the lubricant. And it evaluated similarly. Comparative Example 7 Evaluations were made in the same manner as in Example 1 except that the same developer composition as in Example 1 was used, and the heating roll used was an aluminum core coated with a fluororesin. The surface roughness (Ra) was 0.5 μm. Comparative Example 8 The same evaluation was performed except that the same developer composition as in Comparative Example 3 was used, and the heating roll used was an aluminum core having an aluminum oxide layer coated on the surface thereof. The surface roughness (Ra) was 0.7 μm.

The test methods and evaluation criteria in the above Examples and Comparative Examples are as follows. (1) Warming-up time The heating rolls in each of the examples and comparative examples were set in the Vivace 550 (remodeled) fixing device (manufactured by Fuji Xerox Co., Ltd.), and after turning on the power, the time until the heating roll reached 200 ° C. was measured. . (2) Offset temperature Using a Vivace 550 (modified) fixing device, the heating rolls in each of the examples and comparative examples were set and measured, and the heat roll temperature was increased from 180 ° C. to 250 ° C. in 5 ° C. increments to generate the offset. Was visually confirmed. (In addition, “not generated” means that the occurrence of offset was not confirmed at 250 ° C.) (3) Peeling scratch defect disappearance temperature Vise 550 (remodeling) Using the fixing device, the heating rolls in each Example and Comparative Example were heated. It was set and measured.
This shows the heat roll temperature at which the peeling nail flaws generated in the solid black image at the leading end of the image reach a level that does not cause a problem in practical use. (It should be noted that "not generated" means a lower limit temperature of measurement of 120 ° C.
It is also shown that no peeling nail scratches were generated. (4) Fixing temperature Using a Vivace 550 (modified) fixing device, the heating rolls in each of the examples and comparative examples were set and measured, and evaluated by the ironing test method. (This indicates the heat roll temperature at which an afterimage of a certain fixed area can be exhibited even when subjected to ironing stress.)

(5) Heat Roll Loss Degree The heat roll loss in each Example and Comparative Example was set and measured using a Viverse 550 (modified) fixing device.
After collecting 10,000 copy images, the surface of the heating roll was visually observed for comparison. G0: Roll surface scratch and toner stain are not generated G1: Toner stain is almost not generated, roll surface scratch is generated G2: Roll surface scratch is hardly generated, toner stain is generated G3: Roll surface scratch and toner are generated Stain generation G4: Roll surface scratches and remarkable toner stain generation

(6) Rubbed image intensity: Measured using a Visual 550 (modified) automatic document feeder. Five originals were set in the apparatus and fed, and the backside dirt of the second and subsequent originals was visually checked and graded. (G0 to G1 indicate levels that do not pose a problem in actual use.) G0: No backside stain G1: Slight stains that are difficult to confirm visually G2: Stain that can be visually confirmed occurs G3: Marked stains that can be visually confirmed are generated.

(7) Storage stability A storage test was carried out for 17 hours in an atmosphere of 50 ° C. and 50% RH. Then, it was subjected to a vibration sieving for 5 minutes with a 63 μm sieve to confirm the blocking property. G1: 63 μm sieve passage rate 70% or more G2: 63 μm sieve passage rate 40% or more, less than 70% G3: 63 μm sieve passage rate less than 40% (8) Toner transport amount Vivece 800 (remodeling) as an index of powder fluidity
A toner box (manufactured by Fuji Xerox Co., Ltd.) was used to measure the toner transport amount per hour.

The properties of the lubricants used in the developer compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 8 are shown in Table 1.
In addition, Table 2 shows the constituent materials of the heating roll used, and Table 3 shows the results of the above characteristic evaluation.

[Table 1]

[0085]

[Table 2]

[0086]

[Table 3]

[0087]

As described above, according to the image forming method of the present invention, the toner particles are used as the developer, and the binder resin, the colorant and the lubricant are essential components, and they are polymerized in the presence of the metatheron catalyst as the lubricant. Polyethylene modified by graft-polymerizing the obtained ethylene homopolymer or an ethylene copolymer composed of ethylene and an α-olefin having 3 to 10 carbon atoms with a styrene monomer or an unsaturated carboxylic acid monomer. A toner image is formed on a transfer material using a system wax, and the surface is coated with a metal oxide layer on the surface of a metal oxide layer.・ Because fixing is performed, the warming-up time can be shortened, power consumption can be reduced, that is, fixing can be performed at a lower temperature, and toner resistance can be improved during image formation. Setting property, powder flowability, blocking resistance and a good, it is possible to rub the image intensity to form a good image. Further, since the heating roll has a hard and smooth surface without being damaged by the peeling claw of the fixing roll portion, it is possible to achieve a long service life.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a fixing device used in an image forming method of the present invention.

FIG. 2 is a cross-sectional view of an example of a heating roll used in the image forming method of the present invention.

FIG. 3 is a sectional view of a main part of another example of a heating roll used in the image forming method of the present invention.

FIG. 4 is a sectional view of another example of a fixing device used in the image forming method of the present invention.

FIG. 5 is a sectional view of another example of a fixing device used in the image forming method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixing device, 2 ... Peeling nail, 3 ... Pressure roll, 4 ... Heating roll, 5 ... Roll core, 6 ... Surface coating layer, 7 ... Heating source, 8 ... Heating roll, 9 ... Roll core, 10 ... Aluminum oxide film , 11 ... Heating roll, 12 ... Roll core,
13 ... Oxide film, 14 ... Recess, 15 ... Filler, 16 ...
Oil coating device, 17 ... External heating source, 18 ... Peeling claw.

Claims (6)

[Claims] 1. A process of forming an electrostatic latent image on a latent image holding member, a process of developing the electrostatic latent image with a developer on a developer carrying member to form a toner image, the latent image In an image forming method including a step of transferring a toner image formed on a holding body onto a transfer body, and a fixing step of heating and fixing the toner image,
The toner particles of the developer are ethylene homopolymers obtained by polymerization in the presence of a metacelone-based catalyst, or ethylene-based copolymers of ethylene and an α-olefin having 3 to 10 carbon atoms, and styrene-based monomers. And / or a polyretylene wax modified by graft polymerization of an unsaturated carboxylic acid monomer, and in the fixing step, a heating roll formed by coating the surface of the roll core with a metal oxide layer is used. A characteristic image forming method. 2. The image forming method according to claim 1, wherein the surface of the heating roll is smooth. 3. The image forming method according to claim 1, wherein the thickness of the metal oxide layer of the heating roll is 1 to 100 μm. 4. A fixing roll comprising a heating roll and a pressure roll having an elastic layer is used in the fixing step.
The image forming method according to claim 3. 5. The image forming method according to claim 1, wherein the roll core of the heating roll is made of metal. 6. The modified polyethylene wax is obtained by polymerization in the presence of a metacelone catalyst and has a density of 0.95 g / cm ³ or more and an average molecular weight of 80.
0 to 3000, molecular weight distribution Mw (weight average molecular weight)
/ Mn (number average molecular weight) = 1.1 to 1.8 Ethylene homopolymer or ethylene copolymer 70 to 95
The melt viscosity at 160 ° C. is 15 cps to 25, which is obtained by graft-polymerizing 5 to 30 parts by weight of a styrene-based monomer and / or an acrylic-based monomer in parts by weight.
2. The image forming method according to claim 1, which is a polyethylene wax having 0 cps and a penetration of 1 dmm or less.