JPH02236567A - Image forming method - Google Patents

Abstract

PURPOSE:To obtain stable triboelectrostatic chargeability by using a coloring agent, binder resin and the negative charge control agent selected from a group consisting of specific compds. CONSTITUTION:At least the coloring agent, the binder resin and the negative charge control agent selected from the group consisting of the compds. expressed by formula I to IV are used at the time of supplying a toner formed into a thin layer to a latent image carrier and developing latent images by using a developing device having a toner transporting member, toner layer thickness regulating member and auxiliary member for toner replenishment. In the formula I, X denotes Cl, So2NH2, etc.; A denotes 8 to 16C straight chain or branched alkyl ammonium which may be interrupted by one oxygen atom. The triboelectrostatic charge generated between the toner particles or between the toner and an electrostatic charging member, such as developing sleeve and blade in a one-component type developing system is stabilized in this way and the distribution of the triboelectrostatic charge quantity is uniformized.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a dry toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. The present invention relates to a toner for developing electrostatic images containing a negative charge control agent.

[Prior Art] There are two methods for developing an electrostatic image formed on an electrophotographic photoreceptor or electrostatic recording medium: a method using a liquid developer (wet development method), and a method using a colored developer in a binder resin. Generally, a method (dry development method) using a toner with a dispersed agent or a one-component or two-component developer in which this toner is mixed with a solid carrier is adopted. Each of these methods has its own advantages. -Although it has its disadvantages, the dry development method is now widely used.

By the way, in the above-mentioned toner (developer powder), if a coloring agent such as a dye or a pigment is simply dispersed in a binder resin, the desired chargeability cannot be achieved by 1q, so an appropriate amount of a charge control agent is added thereto. It is normal to have Typical examples of conventional charge control agents include (1) Those that impart a positive charge to the toner, such as nigrosine oil-soluble dyes, quaternary ammonium salts, azine dyes having an alkyl group,
Basic dyes, basic dye lakes, etc. are also used (ii
> Examples of substances that impart a negative charge to the toner include metal-containing dyes such as chromium-containing monoazo complexes, chromium-containing salicylic acid compound complexes, and chromium-containing organic dyes (copper cap cyanine green, chlorine-containing monoazo dyes).

[Problems to be Solved by the Invention] However, although toners containing such conventional charge control agents initially exhibit good development characteristics, they have a short lifespan.
Therefore, when using a photoreceptor, an inconvenient phenomenon such as filming on the photoreceptor is often observed. This is due to the fact that the properties of conventional charge limiting agents are inconsistent and lack stability. In addition, many of these conventional charge control agents tend to decompose during heat kneading during toner production, or are easily decomposed or deteriorated due to mechanical shock, friction, changes in temperature and humidity conditions, etc., and these problems affect charge control performance. The deterioration of development is further strengthened. Furthermore, there is a tendency that many of the conventional charge control agents change depending on the environment.

In particular, in a one-component process that includes at least a toner conveying member and a toner layer pressure regulating member and in which a thin toner layer is formed on the toner conveying member and development is performed, fluctuations in toner chargeability greatly affect the formation of the toner thin layer. This may cause image deterioration.

In any case, most of the charge control agents that have been proposed so far cannot maintain adequate chargeability over a long period of time.

The present invention is an attempt to solve the above-mentioned problems, and its first purpose is to reduce the friction that occurs between toner particles or between the toner and a charge-imparting member such as a developing sleeve or blade in a one-component development system. It is an object of the present invention to provide a toner that is stable in charging, has a sharp and uniform dry zone Nm distribution, and can be controlled to have a charging amount suitable for the developing method used. A second object of the present invention is to provide a toner in a one-component type dry developer that can maintain negative charge control over a long period of time without becoming excessively triboelectric.

A third object of the present invention is to provide a toner that not only provides stable images at all times but also has durability. A fourth object of the present invention is to provide a toner that is free from background smudges and toner scattering and that allows a large number of high-quality images equivalent to the initial images to be obtained even during continuous use.

[Means for Solving the Problems] The present invention includes a toner transporting member, a toner layer thickness regulating member, and a toner replenishment auxiliary member, and the toner replenishing auxiliary member, the toner transporting member, and the toner layer thickness regulating member. When developing a latent image by supplying a thin layer of toner to a latent image carrier using a developing device in which a toner conveying member and a toner conveying member are in contact with each other, at least a colorant, a binder resin, and the following are used. This is an image forming method characterized by using a negative charge control agent selected from the group consisting of compounds represented by formulas (1), (2), (3), and (4).

(However, in the formula, X is CI, Br, SO2 NH2, SO
2CH3, SO2C2H5, A has 8 to 16 carbon atoms
It may also be used with alkylammonium agents which may be interrupted by one straight or branched oxygen atom.

Here, the following are typical examples of the chromium complex type azo compound represented by the above formula (1) used as a negative charge control agent in the present invention.

The negative chargeability control agent contained in the toner used in the image forming method of the present invention is synthesized by known means. These charge control agents may be used alone or in combination of two or more types, and may also be used as other negative charge control agents. 3 No. 5 No. 4 NO, 6 NO. 7. The toner used in the image forming method of the present invention is produced with such a negative charge control agent, a colorant, and a binder resin as essential components.

The content of the negative charge control agent in the toner in the present invention is determined by the toner manufacturing method, taking into account the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and cannot be uniquely limited. However, about 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, per 100 parts by weight of the binder resin.
It's about the weight part. If it is less than 0.1 part by weight, the negative chargeability of the toner will be insufficient, making it impractical. If it exceeds 20 parts by weight, the negative chargeability of the toner will become too large, resulting in decreased fluidity, decreased transferability, and image density. This is undesirable as it leads to a decrease in All the pigments and dyes conventionally used as colorants for toners can be used as the binder used in the present invention. Specifically, carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, calco oil blue, DuPont oil red, quinoline yellow, methylene blue chloride, lid cyanine blue phthalocyanine green, and Hansa yellow G.
Examples include rhodamine 6C lake, quinacridone, benzidine yellow, malachite green hexalate, oil black, azo oil black, rose bengal, monoazo dyes and pigments, disazo dyes and pigments, trisazo dyes and pigments, and mixtures thereof.

Furthermore, as with the binder resin used in the present invention, all of the binder resins that have been used hitherto as binder resins for toners can be used as well as the above-mentioned binders. Specifically, monopolymers of styrene and its substituted products such as polystyrene, polyp-chlorostyrene, and polyvinyltoluene: styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, Styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer,
Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylic nitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene -butadiene copolymer, styrene-isoprene copolymer, styrene-acrylic nitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer,
Styrenic copolymers such as polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyamide resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified gin, terben resin, Examples include phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., and these may be used alone or in combination of two or more.

FIG. 1 is a schematic cross-sectional view of an example of a developing device using a non-magnetic one-component toner useful for carrying out the image forming method of the present invention.

As shown in FIG. 1, the toner 6 contained in the toner tank 7 is forcibly brought to the sponge roller (toner replenishment auxiliary member) 4 by the stirring blade (toner replenishment auxiliary member) 5. 4 will be supplied.

Then, the toner taken into the sponge roller 4 is
By rotating the sponge roller 4 in the direction of the arrow,
The toner is transported to the toner transport member 2, rubbed, and electrostatically or physically adsorbed, and the toner transport member 2 rotates strongly in the direction of the arrow, and the steel elastic blade (toner layer thickness regulating member)
3, a uniform toner thin layer is formed and triboelectrically charged.

Thereafter, the toner is conveyed to the surface of the electrostatic latent image carrier 1 that is in contact with or in close proximity to the toner conveying member 2, and the latent image is developed.

Note that developing devices suitable for the toner of the present invention are not limited to those described above.

[Example] Hereinafter, the contents of the present invention will be explained according to examples.

Note that parts are based on heavy R standards.

Example 1 Styrene-n-butyl methacrylate 100 parts Libon black 10 parts Charge control agent
A mixture consisting of 3 parts of N01 was sufficiently stirred and mixed in a Henschel mixer, then heated and melted in an O-mill at a temperature of 130 to 140°C for about 30 minutes, and then cooled to room temperature.

This mixture was crushed and classified to obtain a toner having a particle size of 5 to 11 μm. Colloidal sealing force is 0.0 for 100 parts of this toner.
Two parts were added and mixed to form a toner. Use this toner first.
When an image was produced using a developing device as shown in the figure, a good image was obtained, and the image quality did not change even after running.

When the charge amount of the toner was investigated using the blow-off method, the initial charge amount was -12.3 μc/g and -12.0 after running.
There was almost no difference from μc/g. Also, 35℃, 90%
Even under a high-humidity environment of RH and a low-humidity environment of 10° C. and 15% RH, images equivalent to the original copy under a normal humidity environment were obtained, and no toner filming on the photoreceptor was observed.

Example 2 Charge control agent N(
A toner was obtained in the same manner as in Example 1, except that No. 12 was used, and an image test was conducted. There was almost no change in the toner charge amount, and it was found that the toner charge amount did not change much under high temperature and humidity environments, low temperature and humidity environments, and normal temperature and humidity environments. A good image equivalent to that of the original copy was obtained.

Example 3 A mixture consisting of 100 parts of styrene-n-butyl methacrylate, 10 parts of carbon black, and 3 parts of the charge control agent of formula (2) was thoroughly stirred and mixed in a Henschel mixer, and then heated in a roll mill at a temperature of 130 to 140°C. The mixture was melted by heating for about 30 minutes, and then cooled to room temperature.

This mixture was crushed and classified to obtain a toner having a particle size of 5 to 10 μm. Colloidal sealing force is 0 for 100 parts of this toner.
．． Two parts were added and mixed to form a toner. Use this toner first.
When an image was produced using a developing device as shown in the figure, a good image was obtained, and the image quality did not change even after running. When the charge amount of the toner was examined using the blow-off method, the initial charge amount was -12. After running at 9 μc/g, it was -12.7 μC/g, which was almost unchanged.

In addition, under a high humidity environment of 35°C and 90%RH,
Even in a low-humidity environment of 15% RH at 15% RH, an image equivalent to the original copy in a normal-humidity environment was obtained, and no toner filming on the photoreceptor was observed.

Example 4 A mixture consisting of 100 parts of styrene-n-butyl methacrylate, 10 parts of carbon black, and 3 parts of a charge control agent of formula (3) was sufficiently stirred and mixed in a Henschel mixer, and then mixed with a roll mill at a temperature of about 130 to 140'C. Heat and melt for 30 minutes,
This was cooled to room temperature.

This kneaded material was crushed and classified to obtain a toner having a particle size of 5 to 10 μm. Colloidal sealing force is 0 for 100 parts of this toner.
．． Two parts were added and mixed to form a toner. Use this toner first.
When an image was produced using a developing device as shown in the figure, a good image was obtained, and the image quality did not change even after running. When the charge amount of the toner was examined by a blow-off method, the initial charge amount was -10.1 .mu.c/g, and after running it was -9.8 .mu.c/g, which was almost unchanged.

In addition, under a high humidity environment of 35°C and 90%RH,
Even in a low-humidity environment of 15% RH at 15% RH, an image equivalent to the original copy in a normal-humidity environment was obtained, and no toner filming on the photoreceptor was observed.

Example 5 Styrene = n-butyl methacrylate 100 parts Carbon plaque 10 parts Charge control agent of formula (4) A mixture consisting of 3 parts was thoroughly stirred and mixed in a Henschel mixer. Melt by heating for about 30 minutes at a temperature of
This was cooled to the lowest temperature.

This mixed material was crushed and classified to obtain a toner having a particle size of 5 to 10 μm. Colloidal sealing force is 0 for 100 parts of this toner.
．． Two parts were added and mixed to form a toner. Use this toner first.
When an image was produced using a developing device as shown in the figure, a good image was obtained, and the image quality did not change even after running. When the charge d of the toner was investigated using the blow-off method, the initial charge amount was -11. After running at Oμc/g, it was -10.5μc/g, which was almost unchanged.

In addition, under a high humidity environment of 35°C and 90% RH,
C. Even in a low humidity environment of 15% RH, an image equivalent to the original copy in a normal humidity environment was obtained, and no toner filming on the photoreceptor was observed.

[Effects of the Invention] As is clear from the above explanation, by using the toner of the present invention containing the specific compound represented by the above formula as a negative charge control agent, an image equivalent to the initial image can be obtained even after continuous copying. You get quality. Further, the toner exhibits stable triboelectrification with negative polarity. Furthermore, it has excellent environmental stability and brings about effects such as being able to easily obtain a black image.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a developing device using a non-magnetic one-component toner useful for carrying out the image forming method of the present invention. 1... Electrostatic latent image carrier 2... Toner transport member 3
... Elastic blade (toner layer thickness regulating member) 4... Sponge roller (toner replenishment auxiliary member) 5... Stirring blade (toner replenishment auxiliary member) 6... Toner 7... Toner tank

Claims (1)

[Scope of Claims] A toner transporting member, a toner layer thickness regulating member, and a toner replenishment auxiliary member, and the toner replenishment auxiliary member,
Using a developing device in which a toner conveying member, a toner layer thickness regulating member, and a toner conveying member are in contact with each other,
When supplying the thinned toner to a latent image carrier to develop a latent image, at least a colorant, a binder resin, and the following formulas (1), (2), (3), and (4) are used. An image forming method characterized by using a negative charge control agent selected from the group consisting of the represented compounds. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (However, in the formula, X is Cl, Br, SO_2NH_2, SO
_2CH_3, SO_2C_2H_5, and A represents an alkyl ammonium having a carbon number of 8 to 16 and may be interrupted by a straight or branched oxygen atom) ▲Mathematical formulas, chemical formulas, tables, etc. are available▼ (2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(3) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(4)