JPH1048867A - Nonmagnetic one-component toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain stable image density during copying repeated many times, to suppress fog and to prevent fusion to a sleeve by sticking a compd. selected from among fatty acid ester, aliphatic ketone, aliphatic ether, etc., to the surfaces of toner particles. SOLUTION: A compd. selected from among fatty acid ester, aliphatic ketone, aliphatic ether, aliphatic amide and aliphatic urea is stuck to the surfaces of toner particles consisting of a bonding resin and a colorant. The selected compd. is synthetic wax excellent in dispersibility, water repellency and lubricity and preferably has >=55 deg.C m.p. The fatty acid ester is synthesized from straight chain fatty acid and straight chain alcohol by esterification. The aliphatic ketone is, e.g. methyl alkyl ketone or ethyl alkyl ketone. The aliphatic ether is, e.g. dialkyl ether or long chain vinyl ether. The aliphatic urea is a compd. having a long chain alkyl group and has high crystallinity and a high m.p. The pref. amt. of the compd. stuck to the toner particles is 0.01-5wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component toner used for developing an electrostatic latent image formed on a photoreceptor by electrophotography or the like.

[0002]

2. Description of the Related Art Conventionally, developing methods used in electrophotography and the like include insulating fine powder mainly composed of a binder resin,
That is, a two-component developing method in which an insulating toner and a magnetic carrier are charged by friction and an electrostatic latent image formed on a photoreceptor is developed by a magnetic brush, a magnetic one-component developing method in which a magnetic one-component toner is used to develop, and a non-magnetic developing method. There is known a so-called non-magnetic one-component developing method in which a magnetic one-component toner is formed in a thin layer on a developing sleeve and developed with or without contact with a photoreceptor. In this non-magnetic one-component developing method, it is necessary to impart a sufficient amount of charge to the non-magnetic one-component toner, as in the two-component developing method, in order to obtain a good visible image.
It is essential to control the thickness of the non-magnetic one-component toner on the developing sleeve uniformly. In order to obtain such characteristics, a rubber or metal blade member is often used by pressing against the developing sleeve for the purpose of regulating the toner layer and imparting charge to the toner. It has also been proposed that a relatively high charge is imparted to a non-magnetic one-component toner by including a charge control agent such as a gold-containing azo dye. However, the conventional non-magnetic one-component toner has a problem that if the pressure of the blade member pressed against the developing sleeve is low, sufficient charge is not applied to the toner to obtain a sufficient image density or fog is large. Was.
Conversely, if the pressure force is high, the charge is sufficiently applied to the toner and the above-mentioned problem is solved. The unevenness causes unevenness in the force applied when the toner passes between the blade member and the developing sleeve, and the thickness of the developer layer is partially increased. The charge amount was insufficient, and density unevenness and fog were generated on the image.
In particular, in the non-contact developing method, the flying characteristics of the toner flying from the developing sleeve to the photosensitive member during continuous copying are deteriorated, and the developing characteristics are likely to be deteriorated. Further, in the conventional non-magnetic one-component toner, a phenomenon in which the toner is fused to the developing sleeve by a pressing force or heat, that is, a problem of so-called sleeve fusion may occur. In addition, the conventional non-magnetic one-component toner has a problem that a large amount of untransferred toner remains on a photoconductor on which a latent image is formed. Therefore, in this case, it is necessary to increase the pressing force of the cleaning member that presses against the photoconductor, but this causes a problem that a filming phenomenon occurs in which the toner is fused to the surface of the photoconductor. Incidentally, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 532-532 discloses a technique of coating a magnetic toner with a fine powder of a hardly soluble stearate, and Japanese Patent Application Laid-Open No. 6-59499 discloses a technique in which a fatty acid metal salt is adhered to the surface and a surface treatment is performed with the fatty acid metal salt. There has been proposed a technique of a developer comprising a carrier. However, the fatty acid metal salt has a disadvantage that the chargeability of the toner is easily inhibited. Therefore, when a fatty acid metal salt is used, in the non-contact non-magnetic one-component developing method, the chargeability of the toner is deteriorated, the flying characteristics to the photoreceptor is inhibited, and the image density is reduced. In addition, regardless of the contact or non-contact method, the charge imparting force of the blade is increased, and blade fusion is likely to occur.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem of the conventional non-magnetic one-component toner, and has been developed in the non-magnetic one-component developing system having a pressing force against a blade member. It is an object of the present invention to provide a non-magnetic one-component toner capable of obtaining an excellent image having a stable image density, less fog, and no sleeve fusion during a copying process.

[0004]

According to the present invention, at least one of a fatty acid ester, an aliphatic ketone, an aliphatic ether, an aliphatic amide and an aliphatic urea is formed on the surface of toner particles comprising at least a binder resin and a colorant. A non-magnetic one-component toner having one type of compound attached thereto.

Hereinafter, the present invention will be described in detail. The compounds used in the present invention are selected from fatty acid esters, fatty ketones, fatty ethers, fatty amides, and fatty ureas. The compound is a so-called synthetic wax having excellent release properties, water repellency and slipperiness, and preferably has a melting point of 55 ° C. or higher. A toner having a melting point of less than 55 ° C. is not preferable because storage stability of the toner deteriorates. In addition, the melting point in the present invention means a peak temperature of an absorption calorie measured by a differential scanning calorimeter (hereinafter, abbreviated as DSC). As the DSC measurement device, for example, SSC-520 manufactured by Seiko Electronics Industry Co., Ltd.
0. The measurement conditions are as follows:
It is weighed and placed on a DSC, and blows 50 ml of N ² gas per minute. Then, the temperature is raised from 20 ° C. to 200 ° C. at a rate of 10 ° C./min.
The process of quenching to ° C. is repeated twice, and the second heat absorption is measured.

The fatty acid ester used in the present invention is synthesized from a linear fatty acid and a linear alcohol by an ester reaction. Specific examples of the fatty acid ester include dodecyl palmitate, tetradecyl palmitate, pentadecyl palmitate, hexadecyl palmitate, octadecyl palmitate, triacontyl palmitate, tetradecyl stearate, hexadecyl stearate, octadecyl stearate, octadecyl stearate, beaconate, and behenate. Examples include docosyl, butyl behenate, hexyl behenate, tetracosyl lignoserate, and myrisyl melysinate. Aliphatic ketones include methyl alkyl ketone, ethyl alkyl ketone, dialkyl ketone and the like. Specific examples of the aliphatic ketone include methyl stearyl ketone, ethyl stearyl ketone, dicapryl ketone, dilauryl ketone, dimyristyl ketone, dipalmityl ketone, distearyl ketone, and the like. Aliphatic ethers include dialkyl ethers and long-chain vinyl ethers. Specific examples of the aliphatic ether include dipalmityl ether, distearyl ether, vinyl lauryl ether, and vinyl myristyl ether.

Aliphatic amides include substituted fatty acid amides such as fatty acid monoamides, fatty acid bisamides, and methylolamide. Specific examples of the aliphatic amide include lauric amide, palmitic amide, stearic amide, behenic amide, hydroxystearic amide, oleic amide, erucamide, ricinoleamide, N
-Stearyl stearamide, N-oleyl oleamide, N-stearyl oleamide, N-oleyl stearamide, N-stearyl erucamide, N-oleyl palmitamide, methylol stearamide, methylol behenamide , Methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisisostearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenebishydroxystearic acid amide, N, N '
-Distearylyl adipamide, N, N'-distearylsepacinamide, ethylenebisoleamide, hexamethylenebisoleamide, N, N'-
Examples thereof include dioleyl adipamide, N, N'-dioleylsepacinamide, m-xylylenebisstearic acid amide, and N, N'-distearylisophthalic acid amide.

[0008] Aliphatic urea is a compound having at least one long-chain alkyl group and has high crystallinity and a high melting point. Specific examples of the aliphatic urea include N-butyl-N′-stearyl urea, N-phenyl-N′-stearyl urea, N-stearyl-N′-stearyl urea, xylylene bisstearyl urea, and toluylene bisstearyl urea And hexamethylene bisstearyl urea.

The toner particles of the present invention are composed of at least a binder resin and a colorant, and appropriately contain an anti-offset agent such as polypropylene and polyethylene, a charge controlling agent, a lubricant for improving fluidity, and the like as appropriate. Is produced by a melt-kneading pulverization method or a polymerization method in the range of 5 to 20 μm. Examples of the binder resin include styrenes such as styrene, α-methylstyrene, and chlorostyrene; and acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, and alkyl acrylate. Kind,
Methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, stearyl methacrylate, glycidyl methacrylate, alkyl methacrylate, acrylonitrile, maleic acid, maleic acid ester, methacrylic acid Homopolymerization or copolymerization of vinyl monomers such as methyl, methyl acrylate, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Styrene resins, epoxy resins, polyester resins, polyurethane resins, and the like. Colorants include carbon black, aniline blue, calco oil blue, chrome yellow, ultramarine blue,
Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal and mixtures thereof, and the like.
These colorants need to be contained in a sufficient ratio to form a visible image having a sufficient density.
The ratio is about 1 to 20 parts by weight to 00 parts by weight. Examples of the charge control agent include a metal-containing complex dye, a nigrosine dye, a quaternary ammonium salt, a triphenylmethane control agent, and a resin control agent.

In the present invention, the amount of the compound attached to the toner particles is preferably 0.01 to 5% by weight. More preferably, it is 0.02 to 3% by weight. If the content is less than 0.01% by weight, problems arise in sleeve fusion, transferability, and image density stability, which is not preferable. On the other hand, if the content is more than 5% by weight, the chargeability is deteriorated due to the presence of a free compound that does not adhere to the surface of the toner particles, and the image density becomes unstable. The method of adhering the compound to the surface of the toner particles in the present invention includes a method of mixing and stirring the toner particles and the compound in a general stirrer such as a turbine type stirrer, a Henschel mixer, a super mixer, or a method manufactured by Nara Machinery Co., Ltd. And a mixture of the two in a surface reforming machine such as an oak mill manufactured by Hosokawa Micron Corporation. Further, the compound on the surface of the toner particles may be formed in a weak adhesion state called a glare to the toner particles, or the compound may be formed in an adhesion state in which a part of the compound is buried in the toner particles, and may be fixed. It may be. In the practice of the present invention, a fluidity improver such as silica may be used together when the compound is attached to the toner particles. The non-magnetic one-component toner of the present invention is used in a non-magnetic one-component developing device. The non-magnetic one-component developing device includes a rubber or metal developing sleeve having a surface for carrying and transporting the non-magnetic one-component toner, and a rubber or metal blade provided near or pressed against the developing sleeve. A non-magnetic one-component toner is supplied to the developing sleeve, and the blade is applied so as to form a thin toner layer with a blade member, and a charge is applied to the developing sleeve. Are brought into contact with each other in a contact or non-contact state, the electrostatic latent image is developed, and then transferred to paper. In particular, when the toner of the present invention is used in a developing method in which the developing sleeve and the photoreceptor are not in contact with each other, there is an effect that the image density is stabilized during continuous copying, which is a conventional problem, and sleeve fusing does not occur.

[0011]

The present invention will be described below with reference to examples. In the examples, parts are parts by weight. Example 1 The raw materials having the above mixing ratios are mixed by a super mixer, hot-melt kneaded by a twin-screw kneader, pulverized by a jet mill, and then classified by a dry air classifier, and the volume average particle diameter by a coulter counter is 9 μm. Toner particles were obtained.
0.2% by weight of distearyl ketone (trade name: Nippon Kasei Co., Ltd .: wax KM, melting point 79 ° C.) and hydrophobic silica (trade name: HV, manufactured by Wacker Chemical Co.)
K-2150) was added and mixed with stirring for 10 minutes to obtain a non-magnetic one-component toner of the present invention.

Synthesis Example 1 340 g (1 mol) of behenic acid and 148 g (2 mol of butanol)
Mol) and sulfuric acid (20 ml) were placed in a round-bottom flask equipped with a stirrer and a condenser, and heated to reflux at 130 ° C. for 4 hours.
After removing excess butanol, the residue was purified with butyl ether to obtain butyl behenate having a melting point of 60 ° C. Example 2 A non-magnetic one-component toner of the present invention was obtained in the same manner as in Example 1 except that distearyl ketone of Example 1 was changed to butyl behenate synthesized in Synthesis Example 1.

Example 3 The distearyl ketone of Example 1 was converted to behenamide (trade name: Diamid B45, manufactured by Nippon Kasei Co., Ltd., melting point: 100 ° C.)
A non-magnetic one-component toner of the present invention was obtained in the same manner as in Example 1 except for changing to.

Example 4 The distearyl ketone of Example 1 was replaced with N-stearyl-N '.
-Stearyl urea (trade name, manufactured by Nippon Kasei Co., Ltd .: Hakclean S)
S, melting point 114 ° C.) to obtain a non-magnetic one-component toner of the present invention in the same manner as in Example 1.

Example 5 A non-magnetic one-component toner of the present invention was obtained in the same manner as in Example 1 except that the distearyl ketone of Example 1 was changed to distearyl ether (melting point: 60 ° C.).

Example 6 A non-magnetic one-component toner of the present invention was obtained in the same manner as in Example 1 except that the addition amount of distearyl ketone in Example 1 was changed to 0.05% by weight.

Example 7 The amount of distearyl ketone of Example 1 was changed to 2.0% by weight.
A non-magnetic one-component toner of the present invention was obtained in the same manner as in Example 1 except for changing to.

Embodiment 8 By adding a polymerization initiator to the polymerizable monomer composition having the above mixing ratio and performing suspension polymerization, a low molecular weight peak in gel permeation chromatography was 800.
0, polymerized toner particles having a high molecular weight peak of 500,000 and a volume average particle size of 8 μm were obtained. Distearyl ketone and hydrophobic silica were stirred and mixed with the polymerized toner particles in the same manner as in Example 1 to obtain a non-magnetic one-component toner of the present invention.

Comparative Example 1 A non-magnetic one-component toner for comparison was obtained in the same manner as in Example 1 except that the distearyl ketone of Example 1 was not used.

Comparative Example 2 A non-magnetic one-component toner for comparison was obtained in the same manner as in Example 1 except that the distearyl ketone of Example 8 was not used.

Comparative Example 3 A non-magnetic one-component toner for comparison was prepared in the same manner as in Example 1 except that the distearyl ketone of Example 1 was changed to lithium stearate (trade name: S-7000F, manufactured by Sakai Chemical Industry Co., Ltd.). I got

The non-magnetic one-component toner obtained in each of the examples and comparative examples was picked up by a full-color copying machine (trade name: FP-C1a, manufactured by Matsushita Electric Industrial Co., Ltd.), which is a non-contact non-magnetic one-component developing device. Characteristics (image density, fog) were evaluated.
Further, a continuous copy test of 10,000 sheets was performed to evaluate image characteristics and sleeve fusion resistance. The image density was measured by a reflection densitometer RD-914 manufactured by Macbeth Co., Ltd., and the fog was measured by a color difference meter Z-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. The sleeve fusing resistance was evaluated by visual observation of the sleeve after continuous copying.

The results are shown in Table 1. According to Table 1, the non-magnetic one-component toner of the present invention has an image density of 1.31.
As described above, fog was 0.23 or less, and the sleeve fusion resistance was good. Further, since the transferability was excellent, the image quality was good with no missing characters, and no filming occurred. On the other hand, in Comparative Examples 1, 2, and 3, the image density decreased after 10,000 sheets, and in Comparative Examples 1 and 2, fusion occurred to the developing sleeve.

[0024]

[Table 1]

[0025]

When the non-magnetic one-component toner of the present invention is applied to a non-magnetic one-component developing device, the image density is stable, good image characteristics are obtained with less fogging, and the sleeve has excellent fusion resistance. This has the operational effect of:

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akihiro Sano 3-1 Yomune Tomoecho, Shizuoka City, Shizuoka Pref.

Claims (3)

[Claims] A fatty acid ester, an aliphatic ketone, or a fatty acid ester, on a surface of toner particles comprising at least a binder resin and a colorant.
A non-magnetic one-component toner comprising at least one compound selected from the group consisting of an aliphatic ether, an aliphatic amide, and an aliphatic urea. 2. The non-magnetic one-component toner according to claim 1, wherein the melting point of the compound is 55 ° C. or higher. 3. A fatty acid ester, an aliphatic ketone, or a fatty acid ester on a surface of toner particles comprising at least a binder resin and a colorant.
A non-magnetic one-component toner for non-contact development, comprising at least one compound selected from aliphatic ethers, aliphatic amides, and aliphatic ureas.