JPH02135370A - Developing method using one component toner - Google Patents

Abstract

PURPOSE:To obtain a toner having characteristic for triboelectric charge having stable negative polarity after long time use or against environmental changes, and to form a picture having a good quality as good as an initial picture by incorporating a specified organoboron compd. into a toner as negative charge controller. CONSTITUTION:In a stage for developing a latent image by feeding a one component toner consisting primarily of a colorant, binder resin, and a positive or negative charge controller onto the surface of an electrostatic image carrier, an organoboron compd. expressed by the formula I is used as controller of negative charge in the toner. In the formula I, X<+> is a cation. Such negative charge controller can be synthesized by a conventional means, which can be used singly or in combination with >=2 kinds of toner. Moreover, it may be used together with other charge controller. Thus, a good picture having picture quality as good as that of an initial picture can be formed after a continuous copy without deteriorating the characteristic for triboelectric charge of a toner due to long time use or environmental changes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a one-component developing method for developing an electrostatic latent image using a one-component toner containing a specific negative charge control agent.

[Prior art]

As a means for developing an electrostatic latent image formed on an electrostatic latent image carrier such as an electrophotographic photoreceptor or an electrostatic recording medium, there are a method using a liquid developer (@Formula Q ('A method), A method (dry development method) using a toner in which a colorant is dispersed in a binder resin or a one-component or two-component dry developer in which this toner is mixed with a solid carrier is generally adopted. Although each method has its advantages and disadvantages, the dry developing method is currently widely used.

By the way, in the above-mentioned toner, dye and dye are simply added to the binder resin.
Since desirable charging properties cannot be obtained by simply dispersing a coloring agent such as a pigment, an appropriate amount of a charge control agent is usually added thereto. Typical examples of conventional charge control agents include (i) agents that impart a positive charge to the toner, such as nigrosine oil-soluble dyes, quaternary ammonium salts, azine dyes having alkyl groups, basic dyes, and Dye lakes and the like can also be used as substances that impart a negative charge to (ii))-ner, such as chromium-containing monoazo complexes, chromium-containing salicylic acid compound complexes, and chromium-containing organic dyes (copper phthalocyanine green, chlorine-containing monoazo dyes).
Examples include metal-containing dyes such as. However, although toners containing such conventional charge control agents initially exhibit good development characteristics, when used for a long time, the performance of the charge control agent deteriorates, and as a result, the triboelectric charging properties of the toner deteriorate, resulting in filming on the photoreceptor. Unfavorable developments, such as the occurrence of oxidation, are often observed. This is because conventional charge control agents tend to deteriorate or decompose easily due to mechanical thermal shock and friction during the thermal kneading process used in toner production, or environmental changes such as temperature and humidity conditions, resulting in lack of stability. This is due to this.

In particular, a developing device equipped with a toner transport member, a toner layer thickness regulating member, and a toner replenishment auxiliary member (however, the toner replenishment auxiliary member and the toner transport member, and the toner layer thickness regulation member and the toner transport member are in contact with each other). In the one-component development method, in which development (copying) is carried out using a one-component toner made into a thin layer by using a single-component toner, fluctuations in the triboelectric charging properties of the toner greatly affect the ability to form a thin toner layer, causing image deterioration. Something happened. In any case, most of the charge control agents that have been proposed so far do not have the desired performance over a long period of time.

[Problem to be solved by the invention]

The object of the present invention is to use a one-component toner containing a negative charge control agent that can maintain the desired performance without degrading the toner's triboelectricity due to long-term use or environmental changes, even after continuous copying. An object of the present invention is to provide a one-component developing method capable of forming an image as good as an initial image.

(Structure/Operation of the Invention) The one-component developing method of the present invention includes a toner conveying member, a toner layer thickness regulating member, and a toner replenishment auxiliary member. A one-component toner containing a colorant, a binder resin, and a positive or negative charge control agent as main components is thinned using a developing device that is in contact with a conveying member, and is applied to the surface of an electrostatic latent image carrier. In the one-component development method in which the latent image is developed by supplying the negative charge control agent in the toner, the negative charge control agent of the general formula described above can be synthesized by known means.These negative charge control agents are: They may be used alone, in combination of two or more, or in combination with other negative charge control agents.

Typical specific examples of the organoboron compound of the above general formula used as a negative charge control agent include the following.

(The following is a blank space.) (In the formula, xo represents a cation.) It is characterized by using an organic boron compound represented by the following.

Contained in the toner used in the developing method of the present invention (hereinafter referred to as blank space) The toner used in the developing method of the present invention includes a coloring agent and a binder resin as essential components along with these negative charge control agents. In order to produce such a toner, the above-mentioned components are heat-kneaded together with other additives if necessary, and after cooling, the resulting mass is crushed and classified, as in the conventional method. Here, the amount of the negative charge control agent used is determined by the toner manufacturing method that takes into account the type of binder resin, the presence or absence of additives, and the dispersion method, and cannot be uniquely limited, but it is 0.1 to 20 parts by weight, preferably 0.1 parts by weight
~10 parts by weight.

If it is less than 0.1 part by weight, the negative chargeability of the toner will be insufficient and it is not practical, and if it exceeds 20 parts by weight, the negative chargeability of the toner will become too large, resulting in a decrease in fluidity, a decrease in transferability, and a decrease in image density. etc., which is undesirable. The amount of colorant used is usually 1 to 100 parts by weight of the binder resin.
The amount is approximately 20 parts by weight, preferably 5 to 15 parts by weight.

All the pigments and dyes conventionally used as toner colorants can be used as the colorant used in the present invention.

Specifically, carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, calco oil blue chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, phthalocyanine green, and Hansa. Yellow G, rhodamine 6C lake, quinacridone, benzidine yellow, malachite green hexalate, oil black, azo oil black, rose bengal, monoazo pigment, disazo pigment.

Examples include trisazo pigments and mixtures thereof.

As for the binder resin used in the present invention, all binder resins that have been used hitherto as binder resins for toners can be used. Specifically, polystyrene, polyP-chlorostin,
Monopolymers of styrene and its substituted products such as polyvinyltoluene! Styrene-P-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer 1, 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 chlormethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene −
Styrenic copolymers such as isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane,
Polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin,
Examples include aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., and these may be used alone or in combination of two or more.

Further, as additives, magnetic powder, inorganic oxide fine powder, etc. can be used.

Next, the method of the present invention will be explained using the developing device shown in FIG.

In the figure, the one-component toner 6 contained in the toner tank 7 is transported by the stirring blade 5 as a toner replenishment auxiliary member.
Sponge roller 4 also serves as a toner replenishment auxiliary member
It is forcibly conveyed and supplied to the top. The toner thus taken onto the sponge roller is conveyed onto the rubber roller 2 as a toner conveying member by the rotation of this roller 4 in the direction of the arrow, and due to friction with this roller 2, electrostatic and physical is adsorbed to. On the other hand, the toner thus deposited on the rubber roller 2 is uniformly thinned and frictionally charged by the rotation of the roller 2 in the direction of the arrow and the steel elastic blade 3 serving as a toner layer thickness regulating member. Next, the thin toner layer on the rubber roller 2 comes into contact with or comes close to the surface of the electrophotographic photosensitive drum 1 serving as an electrostatic latent image carrier, so that a latent image is developed.

It goes without saying that the developing device used in the method of the present invention is not limited to that shown in FIG.

The present invention will be explained in more detail below with reference to Examples. All parts are by weight.

Example 1 A mixture consisting of 100 parts of styrene-n-butyl methacrylate, 10 parts of carbon black, and 3 parts of negative charge control agent (1) was sufficiently stirred and mixed in a Henschel mixer, and then mixed in a roll mill at a temperature of 130 to 140°C for about 30 minutes.
After hot kneading for 0 minutes, the mixture was cooled to room temperature.

This mixed material was pulverized and classified to obtain a toner having a particle size of 5 to 10 μm. When this toner was put into a developing device as shown in FIG. 1 and developed (copied), a good image was obtained, and this image quality did not change even after 10,000 continuous copies.

When the charge amount of the toner was investigated using the blow-off method, the initial charge amount was -16.5 μc/g, and after continuous copying, it was -15.1
There was almost no difference from μc/g.

In addition, under the high temperature environment of 35℃-90% RT
Even in a low humidity environment of .degree. C.-15% RH, an image equivalent to that obtained in a normal humidity environment was obtained, and no toner filming on the photoreceptor was observed.

Example 2 A toner was prepared in the same manner as in Example 1 except that negative charge control agent (2) was used instead of negative charge control agent (1), and a copy test was conducted. , and even under high temperature and humidity environments and low temperature and humidity environments, good images equivalent to those obtained under normal temperature and humidity environments were obtained.

Example 3 100 parts of styrene-2-ethylhexyl acrylate 4° copolymer and 5 parts of polypropylene were used instead of 8100 parts of styrene-n-butyl methacrylate,
Further, a toner was prepared in the same manner as in Example 1 except that negative charge control agent (3) was used instead of negative charge control agent (1). When I did a copy test using this toner, I found that
There was almost no change in the toner charge amount, and even in high temperature and humidity environments and low temperature and humidity environments, good images were obtained that were equivalent to copy images in normal temperature and humidity environments.

[Operations and Effects of the Invention] Since the one-component toner used in the present invention contains the above-mentioned specific organic boron compound as a negative charge control agent, triboelectrification with stable negative polarity can be achieved even during long-term use and environmental changes. Therefore, if continuous copying is performed according to the method of the present invention, an image as good as the initial image can be formed.

[Brief explanation of the drawing]

FIG. 1 is a diagram of an example of an apparatus for carrying out the method of the present invention. 1... Photosensitive drum as an electrostatic latent image carrier 2...
Rubber roller 4 as a toner transport member... Sponge roller 5 as a toner replenishment auxiliary member... Stirring blade as a toner replenishment auxiliary member Ricoh Co., Ltd.

Claims (1)

[Scope of Claims] 1. A toner transporting member, a toner layer thickness regulating member, and a toner replenishment auxiliary member are provided, and the toner replenishment auxiliary member and the toner transporting member are in contact with each other, and the toner layer thickness regulating member and the toner transporting member are in contact with each other. The film was made into a thin layer using a developing device that
In a one-component development method in which a one-component toner containing a colorant, a binder resin, and a positive or negative charge control agent as main components is supplied to the surface of an electrostatic latent image carrier to develop the latent image, the load in the toner is A one-component development method characterized by using an organic boron compound represented by the general formula ▲numerical formula, chemical formula, table, etc.▼ (in the formula, X represents a cation) as an electric control agent.