JPH056024A - Photosensitive toner and electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive toner and electrophotographic sensitive body having a sufficient photosensitivity by essentially consisting 3 binder resin of a specific styrene/acrylic resin. CONSTITUTION:This toner contains the binder resin having an electrical insulating characteristic and zinc oxide and sensitizing dye as a photosensitive material. The binder resin consists essentially of the styrene/acrylic resin contg. a nitrogenous compd. as its constituting component. For example, N-ethyl-N'- methylene urea, N-(2-methoxycarbonyl benzoiloxymethyl)-N'-methylene urea, etc., are used for the nitrogenous compd. This styrene/acrylic resin is obtd. by copolymerizing such nitrogenous compd. and acrylic component (for example, acrylate) and styrene component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive toner and an electrophotographic photosensitive member, and more particularly to a photosensitive toner and an electrophotographic photosensitive member having excellent photosensitivity.

[0002]

2. Description of the Related Art Recently, three kinds of photosensitive toners (cyan toner, magenta toner, and yellow toner) colored in cyan, magenta, and yellow, respectively, are used to form a color image by one exposure and development. A method for forming a film (in a one-shot color system) is drawing attention.

Further, the image forming system using the photosensitive toner is not limited to the analog type image forming apparatus, and in recent years, the use in a laser printer has been considered because the apparatus can be made extremely small. As a laser light source for exposing the laser printer, a gas laser has been conventionally used, but it has many advantages such as excellent intensity and stability of laser light, direct modulation, and low cost. Therefore, a semiconductor laser (780 nm) is often used.

These photosensitive toners are generally made of those containing a binder resin, zinc oxide and a sensitizing dye.

However, in the conventional photosensitive toner, an electrically insulating resin is used as a binder resin, but it cannot be said that it is sufficient in terms of photosensitivity.

The electrophotographic photosensitive member is usually prepared by dissolving a binder resin, a photosensitizer, a charge generating agent, a charge transporting agent and the like in a solvent,
It is prepared by coating this coating solution on a conductive substrate and drying. Such photoreceptors have been widely studied because they have good film-forming performance and high productivity because they can be produced by coating.

However, in the conventional electrophotographic photosensitive member, an electrically insulating resin is used as a binder resin, but it cannot be said that it is sufficient in terms of photosensitivity and a clear image cannot be obtained.

[0008]

The present invention has been made in view of the above points, and an object thereof is to provide a photosensitive toner and an electrophotographic photosensitive member having sufficient photosensitivity.

[0009]

The photosensitive toner of the present invention is a photosensitive toner containing a binder resin, zinc oxide and a sensitizing dye, and the binder resin contains a nitrogen-containing compound as a constituent component. It is characterized in that it contains a styrene-acrylic resin as a main component, whereby the above object is achieved.

Further, the electrophotographic photoreceptor of the present invention is characterized by having a photosensitive layer containing the above-mentioned binder resin, zinc oxide and sensitizing dye, thereby achieving the above object.

Next, the present invention will be described in detail.

First, the photosensitive toner of the first invention will be described.

The photosensitive toner of the present invention contains an electrically insulating binder resin, zinc oxide as a photosensitive material and a sensitizing dye.

The binder resin used in the present invention is a resin whose main component is a styrene-acrylic resin containing a nitrogen-containing compound as a constituent.

The above-mentioned nitrogen-containing compound is, for example, the following [I]
[II] N-ethyl-N'-methylene urea represented by the formula [III], N- (2-methoxycarbonylbenzoyloxymethyl) -N'-methylene urea, and dimethylol ethylene urea can be mentioned.

[0016]

[Chemical 1]

[0017]

[Chemical 2]

[0018]

[Chemical 3]

These nitrogen-containing compounds may be used alone or in combination of two or more.

The nitrogen-containing compound contained in the styrene-acrylic resin is preferably 5 to 50% by weight, and 20 to 20% by weight.
40% by weight is more preferred. When the content of the nitrogen-containing compound in the styrene-acrylic resin is less than 5% by weight, the photosensitivity of the obtained photosensitive toner becomes insufficient.

The acrylic component of the styrene-acrylic resin is acrylic acid, acrylic acid ester, acrylic acid amide, acrylonitrile, methacrylic acid, methacrylic acid ester, methacrylic acid amide, methacrylonitrile, etc. Acrylic acid ester is preferred. To be used The styrene component is styrene or its derivative.
These acrylic components and styrene components may be used alone or in combination of two or more. The content of the acrylic component of the styrene-acrylic resin is 40 to
100% by weight is preferred.

The styrene-acrylic resin can be obtained by copolymerizing these nitrogen-containing compound, acrylic component and styrene component.

In addition to the above-mentioned styrene-acrylic resin, other electrically insulating resin may be added. As such a resin, conventionally known electrically insulating resins may be mentioned, for example, styrene-based polymer, styrene- Butadiene copolymer, styrene-acrylonitrile copolymer, styrene-
Maleic acid copolymer, acrylic polymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin, polycarbonate , Polyarylate, polysulfone, diallyl phthalate resin, silicone resin,
Examples thereof include various polymers such as a ketone resin, a polyvinyl butyral resin, a polyether resin, a phenol resin and the like.
Also, a photoconductive resin such as polyvinylcarbazole can be used alone or in combination with an electrically insulating resin.

The sensitizing dye used in the present invention is a sensitizing dye for zinc oxide.
Conventionally known materials such as cyanine and xanthene are used. By selecting these sensitizing dyes, for example, a photosensitive toner having a photosensitivity in the range of 450 nm to 650 nm or a photosensitive toner for a laser printer having a photosensitivity in the vicinity of 780 nm can be obtained.

The amount of zinc oxide added is preferably 3 to 600% by weight, and preferably 5 to 500% by weight, based on the binder resin.
Is particularly preferable. When the amount of zinc oxide added exceeds 600% by weight, the charge retention property tends to deteriorate, while when the amount of zinc oxide added is less than 3% by weight, the image density and photosensitive toner sensitivity tend to decrease. is there.

The amount of the sensitizing dye added is preferably 0.05 to 10% by weight, more preferably 0.1 to 3% by weight, based on zinc oxide. Addition amount of sensitizing dye is 1
If it exceeds 0% by weight, the chargeability of the photosensitive toner tends to decrease, and the photosensitivity tends to slightly decrease. small.

In the photosensitive toner of the present invention, known components such as dyes, pigments and other colorants, waxes and other offset preventing agents, pressure fixability imparting agents and other auxiliaries are added to the above-mentioned components according to a known formulation. You may.

The photosensitive toner of the present invention comprises the above binder resin,
It is prepared by dispersing or compatibilizing zinc oxide and a sensitizing dye in a solvent and spraying, or by kneading, dispersing and pulverizing the binder resin, zinc oxide and the sensitizing dye.

As the above-mentioned solvent, those which are usually used can be mentioned, for example, toluene, tetrahydrofuran and acetone are preferably used.

The photosensitive toner of the present invention has an average particle size of 8 to 8.
It is preferably 10 μm.

In the present invention, the fact that the photosensitivity is good means that the initial surface potential (Vd) of the charged toner layer and the surface potential after exposure (Vl) are measured, and the surface potential decay rate (%): ( Vd
-Vl) / Vd value is 50% or more, or an electrode is vapor-deposited on the press toner layer, a constant voltage is applied, and the current value before exposure (Id, dark current value), after exposure, The current value (Il, photocurrent value) is measured, and it means that Il is 5 × 10 ⁻⁷ A or more and Il / Id (Gain) is 1.0 × 10 ² or more.

Next, the second invention will be described.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing an electrically insulating binder resin, zinc oxide and a sensitizing dye formed on the surface of a conductive support.

The binder resin used in the present invention is a resin whose main component is a styrene-acrylic resin containing a nitrogen-containing compound as a constituent component used in the first invention.

Examples of the nitrogen-containing compound, the acrylic component and the styrene component include those described in the first invention.

The nitrogen-containing compound contained in the styrene-acrylic resin is preferably 5 to 50% by weight, and 20 to 20% by weight.
40% by weight is more preferred. When the content of the nitrogen-containing compound in the styrene-acrylic resin is less than 5% by weight, the photosensitivity of the obtained photosensitive toner becomes insufficient.

The content of the acrylic component in the styrene-acrylic resin is preferably 40 to 100% by weight.

In addition to the above styrene-acrylic resin, other electrically insulating resin may be added, and examples of such resin include conventionally known electrically insulating resins, for example, those described in the first invention. There are things.

The sensitizing dye used in the present invention is a sensitizing dye for zinc oxide, and examples thereof include those described in the first invention. By selecting these sensitizing dyes, for example, a photosensitive material having a photosensitivity at 450 nm to 650 nm or a photosensitive material for a laser printer having a photosensitivity near 780 nm can be obtained.

The amount of zinc oxide added is preferably 3 to 600% by weight, more preferably 5 to 500% by weight, based on the binder resin.
Is particularly preferable. When the amount of zinc oxide added exceeds 600% by weight, the charge retention property tends to deteriorate, while when the amount of zinc oxide added is less than 3% by weight, the image density and the sensitivity of the photoreceptor tend to decrease. is there.

The amount of the sensitizing dye added is preferably 0.05 to 10% by weight, more preferably 0.1 to 3% by weight, based on zinc oxide. Addition amount of sensitizing dye is 1
When it exceeds 0% by weight, the chargeability of the photoreceptor tends to decrease and the photosensitivity tends to slightly decrease, while when the addition amount of the sensitizing dye is less than 0.05% by weight, the sensitizing effect is small. .

The photoreceptor of the present invention can be obtained by forming a photosensitive layer by coating a conductive support with a coating solution in which zinc oxide and the sensitizing dye are dispersed in the binder resin.

As the above-mentioned solvent, those usually used can be mentioned, for example, the ones described in the first invention are used.

The conductive support is, for example, a simple metal such as aluminum, copper or tin, a plastic material obtained by vapor deposition or laminating of the above metal, glass coated with aluminum iodide, tin oxide, indium oxide or the like. Is mentioned. The conductive substrate may have any shape such as a sheet shape and a drum shape. The support itself may have conductivity, or the surface of the support may have conductivity. The support preferably has sufficient mechanical strength when used.

In the present invention, the thickness of the photosensitive layer is 15 to 15.
It is preferably 30 μm.

[0046]

EXAMPLES The present invention will be specifically described below with reference to comparative examples and examples.

Example 1 33 parts by weight of a styrene-acrylic resin containing styrene, methyl acrylate and N-ethyl-N'-methyleneurea represented by the formula [I] as a constituent, zinc oxide (Gra
de # 2 100 parts by weight of Kyushu Hakushu Chemical Co., Ltd.), 0.1 parts by weight of cyanine dye (NK3425 made by Nihon Sensitive Dye) and 1000 parts by weight of toluene were sufficiently dispersed and mixed, and then photosensitized with an average particle diameter of 10 μm by a spray drying method. Toner was obtained.

Example 2 Instead of the styrene-acrylic resin of Example 1, styrene, methyl acrylate and N represented by the above formula [II] were used.
-(2-Methoxycarbonylbenzoyloxymethyl)
A photosensitive toner having an average particle size of 10 μm was obtained in the same manner as in Example 1 except that a styrene-acrylic resin containing —N′-methyleneurea as a constituent component was used.

Example 3 Instead of the styrene-acrylic resin of Example 1, styrene containing styrene, methyl acrylate and dimethylolethylene urea represented by the above formula [III] as a constituent component
A photosensitive toner having an average particle size of 10 μm was obtained in the same manner as in Example 1 except that an acrylic resin was used.

Comparative Example 1 A photosensitive toner having an average particle size of 10 μm was obtained in the same manner as in Example 1 except that a styrene-methyl acrylate copolymer was used instead of the styrene-acrylic resin of Example 1.

Comparative Example 2 A photosensitive toner having an average particle size of 10 μm was obtained in the same manner as in Example 1 except that a styrene-methyl methacrylate copolymer was used instead of the styrene-acrylic resin of Example 1.

Using the toners obtained in Examples 1 to 3 and Comparative Examples 1 and 2, pellet-shaped samples were prepared by a pressing machine, and a comb-shaped electrode was vapor-deposited on the surface of the sample. And
A voltage of 100 V was applied to this electrode, monochromatic light (780 nm) extracted by a monochromator was irradiated for about 0.5 seconds, and the current value before and after the light irradiation was measured by an electrometer. The results are shown in Table 1.

[0053]

[Table 1]

From Table 1, it can be seen that the photosensitivity of the toners obtained in Examples 1 to 5 is good.

[0055]

As is apparent from the above description, according to the present invention, a photosensitive toner and an electrophotographic photoreceptor having excellent photosensitivity can be obtained. In particular, by selecting a sensitizing dye, it is possible to provide a photosensitive toner and an electrophotographic photosensitive member for a laser printer having excellent photosensitivity even in the near infrared to infrared wavelength region.

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Claims (2)

[Claims] 1. A photosensitive toner containing a binder resin, zinc oxide and a sensitizing dye, wherein the binder resin contains styrene-acrylic resin containing a nitrogen-containing compound as a main component as a main component. Toner. 2. An electrophotographic photoreceptor having a photosensitive layer containing the binder resin according to claim 1, zinc oxide and a sensitizing dye.