JPH0228664A - Photoconductive toner and imaging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus using photoconductive toner.

[Prior Art] As an image forming apparatus using conventional photoconductive toner,
When printing in black, for example, inorganic materials such as dye-sensitized Z n O and dye-sensitized TiO2, or organic photoconductors such as phthalocyanine, quinacridone, and benzidine are used as photoconductive agents to print cyan, magenta, and yellow. Pigmented three-color mixed systems have been used. Another method has been to use a toner in which the photoconductive agent is mixed with a black colorant such as carbon black. In this case, dye-sensitized Zn◯ is often used as the photoconductive agent. In addition, as an example of a process using them, JP-A-60-
There was one shown in 31150.

A visible light source has been used as a light source for conventional image forming apparatuses using photoconductive toner.

Further, as an example of sensitizing zinc oxide to near infrared light, there was an electrophotographic photoreceptor disclosed in Japanese Patent Application Laid-open No. 78358/1983.

[Problems to be Solved by the Invention] However, the following problems have been pointed out in conventional photoconductive toners and image forming apparatuses using photoconductive toners, and solutions are desired.

1. Since toner effectively sensitized to near-infrared rays cannot be obtained, it becomes difficult to use an inexpensive semiconductor laser as a light source, leading to an increase in the cost of the device.

2. When carbon black is used as a black colorant, the absorption range extends from the visible to the infrared, so the photosensitivity of the photoconductive toner is significantly reduced.

3. A three-color mixed system results in a muddy color with a distorted tone and lacks reproducibility.

4. Depending on the amount of colorant added, electrophotographic properties such as photosensitivity and electrical resistance of the toner may be reduced. This is particularly noticeable in a mixed system of a photoconductive agent and a black colorant.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a photoconductive toner with sensitivity in the near-infrared region, while maintaining the chargeability and sensitivity of the photoconductive toner, and producing clear black images. This makes it possible to obtain images with good reproducibility.

[Means for Solving the Problems] The photoconductive toner of the present invention contains at least a black dye, and -Design A-(CH"CH)3 CH=B [wherein A or B is (wherein X is a hydrogen atom] , halogen atom, nitro group.

Cyan group, carbonyl group, carboxyl group, nido e, R
1 is -COOH or an alkali metal salt thereof.

-3O3H or an alkali metal salt thereof, an alkyl group.

R2 may be an anion -COOH, -8°3H
, and I-, C1-, C1○4-, and Br- are allowed to coexist in the molecule in order to neutralize the cations in the heterocycle. m is an integer from 1 to 7. ) is shown. ] It is characterized by containing a sensitizing dye represented by the following and using an azo metal-containing dye as a black dye. Further, the image forming apparatus is characterized in that it uses the above photoconductive toner and uses a semiconductor laser as a light source.

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example] The composition of the photoconductive toner of the present invention is shown below.

It basically consists of a photoconductive pigment, a sensitizing agent, and a binder resin, and a coloring agent is used if necessary.

The following photoconductive pigments are used.

Zinc oxide, titanium oxide, zinc sulfide, selenium, cadmium sulfide, α-silicon.

Any dye can be selected as the sensitizer depending on the photoconductive material and the sensitive wavelength range. For example, triphenylmethane dye, diallylmethane dye, monomethine cyanine, trimethine cyanine, pentamethine cyanine, heptamethine cyanine, styryl dye, oxonol, merocyanine, complex cyanine, azenium dye, azo dye, anthraquinone dye, indigo dye, vinylene dye. , azomethine is used. Examples of these types of dyes include rose bengal, acridine orange, rhodamine B, erythrosis eosin, fluorescein, brilliant green, crystal violet, and the like.

As the black coloring agent, an azo metal-containing dye was used.

Known insulating thermoplastic resins can be used as the binder resin, including acrylic resins such as polyacrylate and polymethacrylate and their copolymers, styrene resins such as polystyrene and poly-1-methylstyrene, and their copolymers. Copolymers, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyester resins and copolymers thereof,
Polycarbonate resin, cellulose resin, and polyarylate resin are used alone or in combination.

Specific examples of the present invention are shown below.

[Example 1] The composition and manufacturing method of the toner according to the present invention are shown below.

Zinc oxide...40 parts by weight Sensitizing dye...0.04 parts by weight Ethyl alcohol...80 parts by weight As a sensitizing dye, a cyanine dye having the following structure was employed.

The above materials were mixed and uniformly dispersed and adsorbed using ultrasonic waves.

Next, the following materials were dissolved in an ethyl alcohol solvent to make them compatible.

Butyral resin...40 parts by weight Black dye-1...20 parts by weight Black dye-1 has a basic structure as shown in Figure 3, and has a naphthalene ring and an azo coupling, with Me as cr,
i, X3 is a long chain methyl group, X2. The one in which X4 was a long-chain ethyl group was used.

The above two raw materials are mixed and further subjected to ultrasonic dispersion to achieve uniform dispersion in the resin. In this way, the raw material solution was prepared to have a solid content of 5%, and was spray-dried to approximately 1% solids.
A 0 μm photoconductive toner (hereinafter referred to as photoner) was produced.

Next, FIG. 1 shows an outline of a process using the image forming apparatus of the present invention. The basic structure consists of a drum, a two-component developer, a writing optical system, an intermediate transfer device, a corona transfer device, a heat roll, and a cleaning brush.

Next, the process will be explained. A photoconductive toner is uniformly formed into a thin layer on a conductive substrate 1 by a two-component magnetic brush method. At this time, the phototoner is in a negatively charged state in the magnetic brush. This negatively charged toner is used in an exposure system 2 to form a latent image. Since zinc oxide is sensitized to near-infrared rays using a sensitizing dye, an inexpensive semiconductor laser can be used as the light source. Further, the light is applied so that the unexposed area becomes an image. after that,
The photoner, which has been exposed to light by the intermediate transfer device 3 whose surface is highly insulating and has become conductive, is removed by applying a bias between it and the conductive substrate. As a result, the negatively charged insulating toner remains on the drum in a visible state. Next, an image is formed on the paper by normal electrostatic transfer using the corona transfer device 6 with the plain paper 9 in between. By passing this through a heat roll 7, it is permanently fixed. The toner remaining on the drum is collected by a cleaning brush 8.

When an image was actually formed through this process, 300
A printing speed of 20 PPM was obtained at the DPI resolution. For the black solid image, O and D values of 1°5 or more were ensured. In addition, good images were obtained with good reproducibility in 10,000 printing tests. The light amount of the exposure system at this time is 1. Oe r g
/ cm 2 , and the bias voltage during intermediate transfer was 750 V or less.

These printing results indicate that the sensitizing dye is sufficiently adsorbed to zinc oxide.
sensitization, demonstrating that the photoconductive toner is functioning as desired by design.

[Example 2] Image formation was performed using the process shown in FIG. 2 instead of the process of Example 1. First, we will outline the process. The drum surface is made of dielectric material, and the inner conductive substrate is grounded. While a developing electric field is being applied by a two-component magnetic brush, light is irradiated by a semiconductor laser to form an image. Only the conductive toner is injected with charge and further adheres to the dielectric surface.

Next, the conductive phototoner is transferred to a corona charger 12.
The image is then passed through plain paper and an image is formed on the paper by normal electrostatic transfer. Further, it is permanently fixed by a heat roll 7. Remove remaining toner with a cleaning brush. In this method, development and exposure are performed simultaneously, increasing speed, and since only one layer is developed by charge injection, it is possible to print with clear images without background smearing.

This indicates that the toner of this example functions as designed in terms of photoresponsiveness as a photoconductive toner, fixability on plain paper as a toner, and black print density.

[Example 3] In Example 1, the same solvent system was used, so the raw material solution could be prepared by simply mixing two raw materials, but in general, the solution for adsorption and the solution for dissolving the resin are often different. Let us now discuss such a case.

A photoconductive toner having the following composition was used.

Zinc oxide...40 parts by weight Sensitizing dye...0.04 parts by weight Ethyl alcohol...80 parts by weight The sensitizing dye was the same as in Example 1.

The above materials were mixed and uniformly dispersed and adsorbed using ultrasonic waves.

Next, the solvent ethyl alcohol is removed by centrifugation to obtain dried dye-adsorbed zinc oxide.

The following materials were dissolved and made compatible in an acetone solvent.

Acrylic resin: 40 parts by weight Black dye-2: 20 parts by weight Black dye-2 has the basic structure as shown in Figure 3, with the naphthalene ring in black dye-1 replaced with a benzene ring as a side chain. In the structure attached as Me, Cr, Xi, X3 is a long chain methyl group, X2. The one in which X4 was an ethyl group was used.

The above-mentioned dye-adsorbed zinc oxide is added to this solution, and further subjected to ultrasonic dispersion so that it is uniformly dispersed in the resin. In this manner, the raw material solution was prepared to have a solid content of 5%, and a phototoner having a thickness of approximately 10 μm was prepared by spray drying.

When the obtained phototoner was used as a developer and passed through the process of Example 2, clear images without blurring were obtained with good reproducibility. This shows that the toner produced in this example is functioning as designed.

[Example 4] In order to develop photoresponsiveness of a phototoner, it is often effective to add a sensitizing aid in addition to a sensitizing dye to increase sensitivity. In this case, the following electron affinity compounds are used as materials.

Acid anhydrides such as iodine, chloroanyl, p-benzoquinone, phthalic anhydride, and maleic anhydride.

In this example, a phototoner was prepared with the following composition.

Zinc oxide: 40 parts by weight Sensitizing dye: 0,604 parts by weight Phthalic anhydride: 0.04 parts by weight Ethyl alcohol: 80 parts by weight The sensitizing dye was the same as in Example 1. Dye-adsorbed zinc oxide was produced using this material system according to the procedure of Example 3.

Next, the following materials were dissolved in an acetone solvent to make them compatible.

Acrylic resin: 40 parts by weight Black dye: 2: 20 parts by weight The previously prepared dye-adsorbed zinc oxide was added to this resin solution and uniformly dispersed to produce a phototoner using a spray drying method.

When the obtained phototoner was used as a developer and passed through the process of Example 2, clear images without blurring were obtained with good reproducibility. This means that the photosensitivity of the photoner produced in this example was 8!, as designed! It shows that it is working. It goes without saying that the type and amount of the sensitizing agent added are not limited to those in this example.

[Example 5] As the toner structure of the present invention, a double-structured microcapsule toner was prepared in which the surface contained excess zinc oxide for photoresponsiveness and the inner core contained excessive resin to ensure fixability.

The composition and manufacturing method of the micro-force self toner are shown below.

First, using acrylic particles with a particle size of 10 μm, black dye-
The particles are directly stained in the alcohol solution of 1 and used as inner core particles.

Next, prepare the following solution.

Zinc oxide...75 parts by weight Cyanine dye...0.075 parts by weight Ethyl alcohol...150 parts by weight Butyral resin・・25 parts by weight The same sensitizing dye as in Example 1 was used.

First, the above materials were mixed except for the resin, and uniformly dispersed and adsorbed using ultrasonic waves.

Next, a resin is added to this dispersion liquid and subjected to ultrasonic dispersion in the same manner to prepare a zinc oxide dispersed resin solution. Furthermore, inner core particles are added to this resin solution and subsequently uniformly dispersed using ultrasonic waves. In this way, the raw material solution was prepared to have a solid content of 10%, and a phototoner whose surface was coated by a spray drying method was prepared. Approximately 1 μm according to electron microscope observation
It was confirmed that the zinc oxide dispersed film was coated with a thickness of .

When this microcapsule toner was subjected to the process of Example 2, good printing was obtained. This indicates that insulation on the surface is ensured, triboelectric charging properties and transferability work as expected, and photoresponsiveness, fixing properties with inner core particles, and coloring properties are achieved as designed.

[Example 6] In the compound of the present invention, one of the hydrogen atoms in the methine chain may be substituted with various substituents as described below. For example -CH3, -C1, -Br
, -I, or fixed in a cyclic structure. Examples of these rings include those shown below. Needless to say, the substituents and cyclic structures in the methine chain are not limited to these.

R=H,Me Q=C)(2,NR X! halogen As a sensitizing dye, Using the compounds shown in the table below, νA A phototoner was prepared.

composition, manufacturing method, printing pro Seth is Example 3 It is similar to

J91 Dye Sensitive Tile Table 1 As is clear from this table, all of the tiles showed good sensitivity and print density.

Although the embodiments have been described above, the process using the photo toner of the present invention is applicable not only to the above embodiments but also to all processes using photoconductive toner.

[Effects of the Invention] As described above, according to the present invention, the photoconductive toner contains at least a black dye and -design A-(CH=CH)a-
CH=B [wherein A or B is (where X is a hydrogen atom, a halogen atom, or a nitro group.

Cyano group, carbonyl group, carboxyl group, nitrile group, Z is O, S, Se, T
e, R+ is -COOH or an alkali metal salt thereof.

-3OaH or an alkali metal salt thereof, an alkyl group.

R2 may be an anion -COOH, -3°3H
, and I-+ C1- and C104-I Br- are allowed to coexist in the molecule in order to neutralize the cations in the heterocycle. m is an integer from 1 to 7. ), and by using an azo metal-containing dye as the black dye, it became possible to provide a black developer with photosensitivity in the near-infrared region. .

Furthermore, an image forming apparatus using the photoconductive toner described above can now use an inexpensive semiconductor laser as a light source.

If an image forming apparatus using the photoconductive toner according to the present invention is used, it has sensitivity in the near-infrared region and can reproduce clear black images while maintaining the chargeability and sensitivity of the photoconductive toner. This has the effect of making it possible to provide a low-cost device that can be obtained with good performance, is small in size, and has a simple process.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a process using the image forming apparatus of the present invention. FIG. 2 is a diagram showing another process of the image forming apparatus of the present invention. FIGS. 3 and 4 are diagrams showing the composition of the black dye used in the photoconductive toner of the present invention. 1, conductive drum 2, two-component magnetic brush developer 3, exposure system 4, photoner 58, intermediate transfer device 6, corona transfer device 7, heat roll 8, cleaning brush 9゜plain paper 10, dielectric substrate 11, conductive Substrate 12, corona charger b Fig. Fig. 3 Fig. 41

Claims (4)

[Claims] (1) As a component of the photoconductive toner, at least a black dye and a general formula A-(CH=CH)_3-CH=B
[In the formula, A or B is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲ Mathematical formulas There are , chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲ There are mathematical formulas, chemical formulas, tables, etc. ▼▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, X is a hydrogen atom, a halogen atom, a nitro group , cyano group, carbonyl group, carboxyl group, nitrile group, Z is O, S, Se, T e, R_1 is -COOH or an alkali metal salt thereof,
-SO_3H or its alkali metal salt, alkyl group,
R_2 may be an anion -COOH, -SO_
3H, and I^-, Cl^-, ClO_4^-, and Br^- are allowed to coexist in the molecule in order to neutralize the cations in the heterocycle. m is an integer from 1 to 7. ) is shown. ] A photoconductive toner comprising a sensitizing dye represented by: (2) The photoconductive toner according to claim 1, wherein an azo metal-containing dye is used as the black dye. (3) An image forming apparatus using the photoconductive toner according to claim 1. (4) The image forming apparatus according to claim 3, wherein a semiconductor laser is used as the light source.