JPH05197206A - Improved toner and formation of two-color image - Google Patents

Abstract

PURPOSE: To provide a toner, a developer and an image forming method which enables formation of a high quality dichromatic image. CONSTITUTION: The toner compsn. contains a resin, a coloring agent, a charge controlling additive comprising a mixture of zinc 3,5-dit-butylsalicylate or aluminum compd. and alkyl pyridinium halide, distearyl dimethylammonlum methylsulfate or distearyl dimethyl ammonium blsulfate, a colloidal silica external additive and a metal salt of fatty acid external additive. A latent image containing high, medium and low potential regions on an image forming member is formed. Then the low potential region is developed with a developer containing the toner and the carrier. The high potential region is developed with a developer containing a second color toner and a carrier. The developed dichromatic image is transferred to a base body and fixed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improved toner compositions and improved methods of forming two-color images.

[0002]

U.S. Pat. No. 4,845,003 discloses a toner for developing electrostatic latent images characterized in that the toner contains an aluminum compound of hydroxycarboxylic acid which may be substituted with alkyl and / or aralkyl. is doing.
U.S. Pat. No. 4,656,112 discloses a toner for developing an electrostatic latent image characterized in that the toner contains a zinc complex compound of an aromatic carboxylic acid with or without a substituent as a charge control agent. is doing. Other related prior arts include US Pat. No. 4,314,017, US Pat. No. 4,604,338 and US Pat. No. 4,206,0.
64, US Pat. No. 4,902,598, US Pat. No. 4,824,750, US Pat. No. 4,904,762.
There is an issue.

A method of charging a photosensitive imaging member to one polarity and forming an image on the member of at least three different potential values of the same polarity is described in US Pat. No. 4,078,929.
No. This U.S. patent includes a first charged area as a background area on the imaging surface, a second area having a higher voltage than the first area and a third area having a lower voltage than the first area, and second and third areas. Disclosed is a method of forming a two-color image by forming a charged image in which a region functions as an image forming region. This charged image is developed with positively charged toner particles of the first color in the first step, and with negatively charged toner particles of the second color in the subsequent developing step. Further, the charged image may be developed in one developing step with a dry developer containing toners of two different colors. However, in accordance with the teachings of that U.S. patent, each image formed has inferior quality compared to images developed in two successive development steps. Also of interest with respect to the tri-potential imaging method are US Pat. Nos. 4,686,163, 4,525,4.
No. 47 and No. 4,640,883.

US Pat. No. 4,948,686 discloses
(1) an image forming member is charged in an image forming apparatus, (2) a latent image including high, medium and low potential regions is generated on the member, (3) a low potential region is made of polyester, A first resin selected from the group consisting of styrene-butadiene polymers, styrene-acrylate polymers, styrene-methacrylate polymers and mixtures thereof, first pigments, charge control agents, colloidal silica surface external additives, and metal salts. Or a color first toner with an external additive including a metal salt of a fatty acid, a core and a coating, the coating comprising methyl terpolymer, polymethylmethacrylate, and about 35 to about 65% by weight polymethylmethacrylate and about 35 to about 65% by weight. 65% by weight selected from the group consisting of chlorotrifluoroethylene-vinyl chloride copolymer blends And 0 to about 40 wt% developed with a developer containing a first carrier containing conductive particles (by coating basis), (4) Subsequently, the high potential region, polyesters, styrene - butadiene polymers,
A black second toner comprising a second resin selected from the group consisting of styrene-acrylate polymers, styrene-methacrylate polymers and mixtures thereof, a second pigment, and a second charge control agent; and a coating comprising a core and a coating. Developing with a developer comprising a chlorotrifluoroethylene-vinyl chloride copolymer containing 0 to about 40% by weight of conductive particles, a second carrier selected from the group consisting of polyvinyl fluoride and polyvinyl chloride, (5) Disclosed is a method of forming a two-color image, which comprises transferring a developed two-color image to a substrate.

[0005]

Although the known compositions and methods are suitable for their intended purpose, they enable the formation of high quality two-color images in a single development, especially between black and color developers. There is a need for toners, developers, and imaging methods that enable as a result of the absence of these interactions. There is also a need for toners, developers, and imaging methods that enable reduction or elimination of edge field development (development of the halo of another color toner surrounding an image developed with one color toner). ing. There is also a need for toner compositions that provide improved developer conductivity. In addition, there is a need for toner compositions that provide improved developer mixing properties, the amount of time that new toner added to a mixture of toner particles and carrier particles takes to acquire the desired triboelectric charge. Therefore, the object of the present invention is
Toner that enables high-quality two-color images to be formed by one-time development,
A developer and an imaging method.

[0006]

SUMMARY OF THE INVENTION The above and other objects of the present invention are directed to charging an imaging member to a high level on the imaging member.
A latent image including each region of medium and low potential is formed, and the low potential region is formed by resin; coloring agent; (a) 3,5-di-t-butylsalicylate zinc compound, (b) 3,5-di- a mixture of a zinc t-butylsalicylate compound and an alkylpyridinium halide, (c) a mixture of a zinc compound of 3,5-di-t-butylsalicylate and a distearyl dimethyl ammonium methyl sulfate, (d) 3,5-
Zinc di-t-butylsalicylate compound and distearyl
Mixture with dimethyl ammonium bisulfate,
(E) a mixture of 3,5-di-t-butylsalicylic acid aluminum compound and an alkyl pyridinium halide, (f) a mixture of 3,5-di-t-butylsalicylic acid aluminum compound and distearyl dimethyl ammonium methyl sulfate, ( g) 3,5-di-t
A mixture of an aluminum butylsalicylate compound and distearyl dimethyl ammonium bisulfate, and a charge control additive selected from the group consisting of these mixtures; a colloidal silica external additive; and a fatty acid metal salt external additive Develop with a developer containing color toner and carrier, and then add high potential area to the second
A method of forming a two-color image, which comprises developing with a developer containing color toners and carriers, transferring the developed two-color image to a substrate, and permanently fixing the image to the substrate as necessary. It can be achieved by providing.

According to another embodiment of the present invention, (1) a latent image including high, medium and low potential regions is formed on an image forming member in an image forming device, and (2) a low potential region. Selected from the group consisting of polyesters, styrene-butadiene polymers, styrene-acrylate polymers, styrene-methacrylate polymers and mixtures thereof present in an amount of from about 80 to about 98.8 wt% by conductive magnetic brush development. A first resin; a copper phthalocyanine pigment present in an amount of about 1 to about 15% by weight, a substituted copper phthalocyanine pigment,
A first pigment selected from the group consisting of halogenated phthalocyanine pigments, quinacridone pigments, azo pigments, rhodamine pigments and mixtures thereof; present in an amount of about 0.1 to about 5% by weight (a) 3,5- A zinc di-t-butylsalicylate compound, (b) a mixture of a zinc compound of 3,5-di-t-butylsalicylate and an alkylpyridinium halide,
(C) a mixture of 3,5-di-t-butylsalicylate zinc compound and distearyl dimethyl ammonium methyl sulfate, (d) a 3,5-di-t-butyl salicylate zinc compound and distearyl dimethyl ammonium bisulfate Mixture, (e) 3,5-di-
Aluminum t-butylsalicylate and alkyl
Mixture with pyridinium halide, (f) Mixture of 3,5-di-t-butylsalicylic acid aluminum compound and distearyl dimethyl ammonium methyl sulfate, (g) 3,5-Di-t-butylsalicylic acid aluminum compound and distearyl Mixtures with dimethyl ammonium bisulfate, and charge control additives selected from the group consisting of these mixtures; about 0.1.
A first color first toner comprising a colloidal silica external additive present in an amount of about 2 wt%; and a fatty acid metal salt external additive present in an amount of about 0.1 to about 2 wt%; A steel core having an average diameter of 25 to about 215 microns and a coating, the coating comprising methyl terpolymer, polymethyl methacrylate, and about 35 to
About 65% by weight of polymethyl methacrylate and about 35-
Selected from the group consisting of about 65% by weight of a blend of chlorotrifluoroethylene-vinyl chloride copolymer and 0 to
Developing with a developer comprising a first carrier containing about 40% by weight (based on coating) of conductive particles and having a coating amount of about 0.2% to about 3% by weight of the carrier;
(3) Subsequently, the high potential area is present by conductive magnetic brush development in an amount of about 80 to about 98.8 wt% polyester, styrene-butadiene polymer, styrene-acrylate polymer, styrene-methacrylate polymer and the like. A second resin selected from the group consisting of: a second pigment present in an amount of about 1 to about 15% by weight, and a second charge control agent present in an amount of about 0.1 to about 6% by weight. A second toner of a second color containing a steel core having an average diameter of about 25 to about 215 microns and a coating, the coating being from 0 to about 1.5% by weight of the carrier of the coating amount. Chlorotrifluoroethylene-vinyl chloride copolymer containing about 40% by weight conductive particles, about 0.01 to about 0.2 of carrier.
Developed with a developer comprising a coating weight of polyvinyl fluoride and a carrier of a second carrier selected from the group consisting of 0.01 to about 0.2 weight percent coating of polyvinyl chloride. ) A method of forming a two-color image, which comprises transferring the developed two-color image to a substrate.

Another embodiment of the present invention is a resin; a colorant; (a) a mixture of a zinc 3,5-di-t-butylsalicylate compound and an alkylpyridinium halide,
(B) a mixture of 3,5-di-t-butylsalicylate zinc compound and distearyl dimethyl ammonium methyl sulphate, (c) a mixture of 3,5-di-t-butyl salicylate zinc compound and distearyl dimethyl ammonium bisulfate Mixture, (d) 3,5-di-t-butylsalicylic acid aluminum compound and alkyl pyridinium halide, (e) 3,5-
From a mixture of an aluminum di-t-butylsalicylate compound and a distearyl dimethyl ammonium methyl sulphate, (f) a mixture of an aluminum compound of 3,5-di-t-butyl salicylate and a distearyl dimethyl ammonium bisulfate, and mixtures thereof A toner composition comprising a charge control additive selected from the group consisting of: a colloidal silica external additive; and a fatty acid metal salt external additive. Yet another embodiment of the present invention forms an electrostatic latent image on an imaging member, the latent image being combined with a resin; a colorant; (a) a 3,5-di-t-butylsalicylate zinc compound. A mixture with an alkyl pyridinium halide, (b) a mixture of 3,5-di-t-butylsalicylic acid zinc compound and distearyl dimethyl ammonium methyl sulfate, (c) 3,5-
Zinc di-t-butylsalicylate compound and distearyl
Mixture with dimethyl ammonium bisulfate,
(D) A mixture of 3,5-di-t-butylsalicylate aluminum compound and an alkyl pyridinium halide, (e) 3,5-di-t-butylsalicylate aluminum compound and distearyl dimethyl ammonium
Mixture with methyl sulfate, (f) 3,5-di-
Toner containing a mixture of an aluminum t-butylsalicylate compound and distearyl dimethyl ammonium bisulfate, and a charge control additive selected from the group consisting of these mixtures; a colloidal silica external additive; and a fatty acid metal salt external additive The present invention relates to an image forming method, which comprises developing with a composition, transferring the developed image to a substrate, and optionally fixing the transferred image permanently to the substrate.

The toners of the present invention generally include one or more resins; one or more pigments; (a) 3,5-di-t-butyl zinc salicylate compound, (b) 3,5-di-t-. A mixture of a zinc butylsalicylate compound and an alkyl pyridinium halide, (c) A mixture of a zinc compound of 3,5-di-t-butylsalicylate and a distearyl dimethyl ammonium methyl sulfate, (d) 3,5-di-t-butyl A mixture of a zinc salicylate compound and distearyl dimethyl ammonium bisulfate,
(E) a mixture of an aluminum compound of 3,5-di-t-butylsalicylate and an alkylpyridinium halide,
(F) a mixture of 3,5-di-t-butylsalicylic acid aluminum compound and distearyl dimethyl ammonium methyl sulfate, (g) 3,5-di-t-
Aluminum butylsalicylate and distearyl
Mixture with dimethyl ammonium bisulfate,
And a charge control additive selected from the group consisting of a mixture thereof; a colloidal silica external additive; and a fatty acid metal salt external additive. Suitable resins include polyesters and styrene-butadiene polymers, especially from about 83 to about 93% by weight of a styrene component such as those commercially available from Goodyear as Pliolite or Pliotone. There is a styrene-butadiene copolymer present in an amount of about 88% by weight and the butadiene component in an amount of about 7 to about 17% by weight, preferably about 12% by weight. In addition, the styrene-acrylate polymer and the styrene-n-butylmethacrylate polymer, especially the styrene component is about 50 to 50%.
Present in an amount of about 70% by weight, preferably about 58% by weight, n
Also suitable are styrene-n-butyl methacrylate copolymers in which the -butyl methacrylate component is present in an amount of about 30 to about 50 weight percent, preferably about 42 weight percent. Also particularly suitable for inclusion in the toner of the present invention is the styrene component present in an amount of from about 50 to about 80, preferably about 65% by weight, and the n-butylmethacrylate component from about 50 to about 20% by weight. Styrene present in an amount of about 35% by weight
It is an n-butyl methacrylate polymer. The resin is generally present in an amount of about 80 to about 98.8% by weight.

Suitable toner pigments include copper phthalocyanine pigments, substituted copper phthalocyanine pigments, halogenated phthalocyanine pigments, quinacridone pigments, azo pigments, rhodamine pigments, and mixtures thereof. Specific examples include:
Fernal Pink, commercially available from BASF, Sudan Blue OS, commercially available from BASF, Neopen Blue, commercially available from BASF, PV First, commercially available from Hoechst-Celanese. Blue, Litol Scarlet, commercially available from BASF, Heliogen Green K-9360, commercially available from BASF, Hosta Palm Pink E pigment, commercially available from Hoechst-Celanese, commercially available from Mobay Chemicals. Funcon Fast Red R-622
6. Permanent Yellow FGL, Pigment Red 4 commercially available from Hoechst-Celani's
There is a monoazo pigment such as 8: 1. Generally, the pigment is present in an amount of about 1 to about 15% by weight, preferably about 2 to about 10% by weight.

Suitable charge control agents for the toners of this invention include Bontron E-84 available from Orient Chemical Company of Japan or US Pat. No. 4,65.
3,5-di-t-butylsalicylate zinc compounds such as zinc compounds as disclosed in 6,112;
Zinc 5-di-t-butylsalicylate compounds and alkylpyridinium halides such as cetylpyridinium chloride disclosed in U.S. Pat. No. 4,298,672, as disclosed in U.S. Pat. No. 4,560,635. Distearyl dimethyl ammonium methyl sulphate, or US Pat. No. 4,937,1
Mixtures with secondary charge control agents such as distearyl dimethyl ammonium bisulfate as disclosed in US Pat. No. 57; and Bontron E-88 or U.S. Pat. No. 4,84 available from Orient Chemical Company of Japan.
3,5-di-t-butylsalicylic acid aluminum compounds such as aluminum compounds as disclosed in US Pat. No. 5,003, and alkylpyridinium halides such as cetyl pyridinium chloride, distearyl dimethyl ammonium methyl sulphate, and distearyl dimethyl. Mixtures with secondary charge control agents such as ammonium bisulfate; and mixtures thereof. The zinc compound charge control agent is a compound of zinc with 3,5-ditertiary-butylsalicylic acid as disclosed in US Pat. No. 4,656,112.

The aluminum compound charge control agent is a compound of aluminum with 3,5-di-t-butylsalicylic acid, and, according to US Pat. No. 4,845,003, aromatic hydroxy having alkyl and / or aralkyl. It is prepared from a carboxylic acid by treating this acid with an aluminum donor in a known manner. The charge control agent or mixture of charge control agents is generally about 0.1.
To about 10% by weight, preferably about 0.25 to about 3% by weight, although other amounts may be present as long as the objects of the invention are achieved. In one preferred embodiment, the charge control agent is a mixture of either a zinc 3,5-di-t-butylsalicylate compound or an aluminum 3,5-di-t-butylsalicylate compound and the second charge control agent. And the second charge control agent is present in the toner at about 0.
1 to about 1% by weight, preferably about 0.25 to about 0.75% by weight.

In addition, Aerosil R972 and Erodil R97 available from Degussa
6, colloidal silica such as Erodil R812, and external additives of metal salts or metal salts of fatty acids such as zinc stearate, magnesium stearate, aluminum stearate, cadmium stearate are mixed on the toner of the present invention. .. Generally, toners containing these additives on their surface are described in US Pat. Nos. 3,590,000, 3,720,617, 3,900,588 and 3,983,045. It is disclosed. Generally, colloidal silica is present in an amount of from about 0.1 to about 2% by weight of the toner, preferably about 0.3% by weight, and a metal salt additive such as zinc stearate is added from about 0.1 to about It is present in an amount of 2% by weight, preferably about 0.3% by weight. By changing the amounts of these two types of external additives, the charge value and conductivity of the toner can be adjusted. For example, increasing the amount of colloidal silica generally involves adjusting the triboelectric charge in the negative direction and mixing time, which is the amount of time it takes for fresh toner to triboelectrically charge after contact with the carrier. Is a measure). In addition, increasing the amount of zinc stearate improves mixing time, makes the developer composition more conductive, regulates triboelectric charge in the positive direction, and further improves humidity sensitivity.

A particularly preferred embodiment of the present invention is 90% by weight of styrene-butadiene resin such as Pliolite.
7% by weight of pigments such as PV Fast Blue B2G-A and 3,5-di-t-such as Bontron E-84
Colloidal silica, such as Erosir R-972, containing 3% by weight of zinc butylsalicylate compound and present in an amount of about 0.3% by weight of the toner and about 0.3% by weight of the toner.
To each of the external additives of metal salts of fatty acids such as zinc stearate present in Another particularly preferred embodiment of the present invention is 90.5% by weight styrene-butadiene resin such as Pliolite, 7% by weight pigment such as PV Fast Blue, Bontron E-8.
2% by weight of a zinc 3,5-di-t-butylsalicylate compound such as 4 and 0.5% by weight of an alkylpyridinium halide such as cetylpyridinium chloride
And colloidal silica such as Erosir R-972 present in an amount of about 0.3% by weight of the toner and a metal salt of a fatty acid such as zinc stearate present in an amount of about 0.3% by weight of the toner. And a toner containing each external additive. Yet another particularly preferred embodiment of the present invention is a styrene-butadiene resin 9 such as Priolite.
0.5% by weight, pigment 7 like PV First Blue
Wt%, 3,5-di-t-such as Bontron E-88
2% by weight of aluminum butylsalicylate compound, and alkyl such as cetyl pyridinium chloride
Colloidal silica, such as Erosir R-972, containing 0.5% by weight of pyridinium halide and present in an amount of about 0.3% by weight of the toner and about 0.3% by weight of the toner.
To each of the external additives of metal salts of fatty acids such as zinc stearate present in

A color developer suitable for the image forming method of the present invention contains the toner of the present invention and a carrier. Any suitable electrophotographic carrier can be used. When using a developer to develop the two-color according to the method of the present invention, preferred carrier is generally electrically conductive, for example, from about 10 ^-14 to
It exhibits a conductivity of about 10 ⁻⁶ (ohm-cm) ^−1, preferably about 10 ⁻¹¹ to about 10 ⁻⁷ (ohm-cm) ⁻¹ . Conductivity can generally be controlled by the choice of carrier core and coating; the carrier can be made conductive by partially coating the carrier core or by coating the core with a coating of carbon black containing material. In addition, irregularly shaped carrier surfaces and toner concentrations of about 0.2 to about 5 will also make the developer generally conductive. The addition of surface additives such as zinc stearate to the surface of the toner particles also makes the developer conductive, the conductivity value increasing with increasing additive concentration. The preferred carrier for the developer of the present invention is Hoeganos, Riverton, NJ.
Noes) available from about 25 to about 215 average diameter.
Micron, preferably Hoeganoes anchor steel grit having about 50 to about 150 microns or Pometom S.P. from Venice, Italy. P. A. An average diameter of about 25 available from Toniolo
To about 215 microns, preferably about 50 to about 150 microns, generally including a preferably unoxidized steel core, such as a Toniolo non-round steel. The carrier particles are methylter containing from 0 to about 40% by weight of carbon black or conductive particles such as other conductive particles as disclosed in U.S. Pat. No. 3,533,835 in a uniform dispersion. It can be coated by solution coating of polymer, and the coating amount is about 0.2 of the carrier core.
To about 3% by weight, preferably about 0.4 to about 1.5% by weight. The carrier coating may also comprise carbon black or any other suitable conductive material in an amount of 0 to about 40% by weight.
It may preferably comprise polymethylmethacrylate contained in an amount of from about 10 to about 20% by weight (based on polymethylmethacrylate), the coating amount being from about 0.2 to about 3% by weight of the carrier core, preferably about 1% by weight. Is. A third possible carrier coating for the developer carrier is about 35 to about 65 wt% polymethyl containing conductive particles in an amount of 0 to about 40 wt%, preferably about 20 to about 30 wt%. Methacrylate and about 35 to about 65 weight percent chlorotrifluoroethylene-vinyl chloride copolymer (OXY46 from Occidental Petroleum).
1) commercially available) and the coating amount is from about 0.2 to about 3% by weight of the carrier core, preferably about 1% by weight. Preference is given to applying the carrier coating on the carrier core by the solution coating method.

Color developer compositions of the present invention prepared from the toners and carriers described above generally contain from about 0.5 to about 5 weight percent toner and from about 95 to about 99.5 weight percent carrier. However, the toner to carrier ratio can vary as long as the object of the invention is achieved. For example, the image forming apparatus used in the method of the present invention has about 55% toner and about 4% by weight toner.
It can be replenished with a color developer containing 5% by weight of carrier. The triboelectric charge of color toners is generally about -10 to -3.
0 preferably about -15 to about -20 microcoulombs / g
However, the value may be outside this range as long as the object of the present invention is achieved. The particle size of the color toners is generally from about 7 to about 20 microns, preferably about 13 microns by volume average diameter, although values may be outside this range as long as the objects of the invention are achieved. The color developer of the present invention is particularly suitable for a two-color image forming method in which a latent image containing high, medium and low potential regions is developed with two different color developers. Imaging members suitable for use in the method of the present invention can be of any type capable of maintaining three different potential values. Generally, a variety of dielectric or photoconductive insulating materials suitable for use in xerography, ionography or other electrophotography can be used, with suitable photoreceptor materials including amorphous silicon, US Patent No. 4,265,990
There are multilayer organic materials and the like as disclosed in No.

The photosensitive imaging member may be positively, negatively or both charged and the latent image formed on its surface may be of either positive or negative potential, or both. In one embodiment, the image consists of three different potential values, all of the same polarity. Each potential value is at least 100
The bolts should be well distinguished, preferably at 200 volts or more. For example, the latent image on one imaging member may consist of -800, -400 and -100 volt potential regions. Furthermore, each potential value can consist of a range of potentials. For example, one latent image may consist of high potential values in the range of about -500 to about -800 volts, medium potential values of about -400 volts, and low potential values in the range of about -100 to about -300 volts. An image having each potential value over a wide area develops a gray area of one color in a high range,
Develop another color gray area in the low range and
The 0 volt potential can be generated such that it distinguishes between high and low ranges and constitutes an intermediate non-development range. In this case, a potential of 0 to about 100 volts may distinguish between high and medium potential values, and 0 to about 100 volts may distinguish between medium and low potential values. When using a multi-layered organic photoreceptor, the preferred potential range is about -700 to about -850 volts at high potential values and about -350 to about -450 volts at medium potential values.
And about -100 to about -180 volts at low potential values. These values will depend on the imaging member used.

A latent image containing three potential values (hereinafter referred to as a three potential image) is formed on the image forming member in US Pat. No. 4,078,9.
It may be formed by any of a variety of suitable methods, such as the method disclosed in No. 29. For example, a tri-potential charged image may be obtained by uniformly charging an image forming member in the dark to a single polarity on an image forming member, and then a sheet of gray paper having both white and black images on the surface. Such a xerographic method may be used to expose a base paper having both bright and dark areas rather than background areas. In a preferred embodiment, the tri-potential image may be formed by a raster output scanner that modulates the laser light as needed when scanning a uniformly charged photoconductive imaging member. In this embodiment, the high potential region is formed by turning off the light source, the medium potential region is formed by exposing the imaging member to the light source at partial power, and the low potential region is formed by exposing the imaging member to the light source. Formed by exposing at output. Other electrophotographic and ionographic imaging methods can also be used.

Generally, in the method of the present invention, the highlight areas of the image are developed with the developer of the present invention which has a first color which is not normally black, and the remainder of the image is usually black (other colors Can also be used) with the second developer. For purposes of simplicity in describing the present invention, the first color toners are referred to as "color toners" or "colorized toners" and the second color toners are referred to as "black toners." Can also have any color. Generally, the highlight color portions are first developed to minimize interaction between the two developers, thereby maintaining a high quality black image. Development is generally by the magnetic brush development method disclosed in US Pat. No. 2,874,063. This method involves magnetically conveying a developer material containing toner and magnetic carrier particles. The magnetic field of the magnet causes the magnetic particles to be arranged in a brush shape, and the "magnetic brush" described above contacts the surface of the electrostatic image bearing photoreceptor. Toner particles are attracted from the brush to the electrostatic image by the electrostatic attraction to the undischarged areas of the photoreceptor causing image development. In the method of the present invention, the conductive magnetic brush method is generally preferred, in which the developer contains conductive carrier particles and the electric field between the biased magnets can be conducted to the photoreceptor through the carrier particles. Conductive magnetic brush development is commonly used in the process of the present invention in view of the relatively small development potential of approximately 200 volts which is generally available, and conductive development utilizes sufficient toner under these development potentials for photoreceptors. On top to ensure that you get an acceptable image density. Conductive development is also preferable in order to prevent the edge electric field generated around the edge of the image developed by one developer from being developed by the toner of another developer.

During the developing process, the developer housing is biased to a voltage between the developing potential value and the intermediate charge value on the imaging member. For example, if the electrostatic image consists of a high potential value of about -800 volts, a medium potential value of about -400 volts, and a low potential value of about -100 volts, a development containing positively charged toner to develop the high potential area. The developer housing may be biased at about -500 volts and the developer housing containing the negatively charged toner developing low potential areas may be biased at about -300 volts. These biases provide a development potential of about -200 volts in the high potential areas developed with positively charged toner and about +200 volts in the low potential areas developed with negatively charged toner. Background fouling is suppressed by holding the background intermediate voltage between a bias on the first developer housing and a bias on the second developer housing. Generally, the housing containing the positive toner is set to about 1 from the medium potential value.
The housing containing the negative toner is biased to a voltage higher than 0 to about 150 volts and the housing containing the negative toner is set to about 100 to about 1 above the medium potential.
Biased to a voltage as low as 50 volts, but these values may be outside these ranges as long as the objects of the invention are achieved. The developed image is then transferred to any suitable substrate such as paper, transparency material and the like. Prior to transfer, the developed image is preferably charged by a corotron to charge both toners to the same polarity, thereby promoting transfer. Transfer is obtained by any suitable means, such as by charging the backside of the substrate with a corotron to the opposite polarity of the toner. The transferred image is then permanently fixed to the substrate by any suitable means. In the toner of the present invention, fixing by heating and pressure is preferable.

A black developer that may be suitable for the method of the present invention comprises a toner and a carrier. A preferred carrier is an average diameter of about 25 to about 215 microns with a coating of chlorotrifluoroethylene-vinyl chloride copolymer (commercially available as OXY461 from Occidental Petroleum) about 50 to about 15 microns.
A steel core, such as a 0 micron Hoeganoes anchor steel grit, is generally included, and the above coating has a coating amount of about 0.4 to about 1.5 wt% and 0 to about 40 wt% uniformly dispersed in the coating. Containing conductive particles. The coating is typically solution coated onto a carrier core from a suitable solvent such as methyl ethyl ketone or toluene. Also, the carrier coating is about 0.01% of the carrier.
A coating of polyvinyl fluoride (commercially available as Tedlar from EI DuPont) present in a coating amount of about 0.2 wt%, preferably about 0.05 wt% may be included. Polyvinyl chloride coatings are generally coated by the powder coating method in which the carrier core is coated with polyvinyl fluoride in powder form and then heated to fuse the coating. In one preferred embodiment, the carrier comprises an unoxidized steel core mixed with polyvinyl fluoride (Tedlar), the polyvinyl fluoride being present in an amount of about 0.05% by weight of the core. This mixture is then heated to about 400 ° F (20 ° F) in the kiln.
(4.4 ° C.) to activate the polyvinyl fluoride coating on the core. The resulting carrier is about 7.6 x 1
It shows a conductivity of 0 ^-10 (ohm-cm) ^-1 . If desired, an additional coating of polyvinylidene fluoride (commercially available from Penwalt, Inc. as Kynal) is provided at about 0.01 to about 0.2 wt% on the other coating of the carrier in black developer. Powder coating may be performed with the coating amount of. Carriers for black developers generally have a conductivity of about 10 ^-14 to about 10 ^-7, preferably about 10 ^-12 to about 10 ^-9 (ohm-cm) ^-1 .

Black toners suitable for image development generally include resins, pigments and charge control additives. Suitable resins include polyesters, styrene-butadiene polymers, styrene-acrylate polymers and styrene-acrylate polymers.
Methacrylate polymers, especially about 50 styrene components
To about 80% by weight, preferably about 58% by weight,
About 20 to about 50% by weight of n-butyl methacrylate component
Styrene-n-, preferably present in an amount of about 42% by weight.
There is a butyl methacrylate copolymer. Generally, the resin is present in an amount of about 80 to about 98.8 wt%, preferably 92 wt%. Suitable pigments include pigments such as carbon black such as Regal 330 (commercially available from Cabot), as well as any other pigment other than black. The pigment is generally present in an amount of about 1 to about 15% by weight, preferably about 6% by weight. Suitable charge control agents for the black toner of the present invention include alkyl pyridinium such as distearyl dimethyl ammonium methyl sulfate, cetyl pyridinium chloride.
There are halides, etc. Charge control agent is about 0.1 to about 6% by weight
Is preferably present in an amount of about 2% by weight. Further, the black toner comprises about 8 to about 20% by weight of magnetite such as mapico black, preferably about 15 to about 16% by weight.
Can be contained in an amount of. Toners containing magnetite suitable in the present invention are about 71.25 to about 87.8 wt% resin, about 8 to about 20 wt% magnetite, about 4 to about 7 wt%.
Wt% carbon black, and about 0.2 to about 1.7.
It generally contains 5% by weight of a charge control agent.

In addition, an eroge available from Degussa
R972, Erosir R976, Erosir R81
Colloidal silica such as 2 and zinc stearate, su
Metal salts such as magnesium thearate or fatty acid metal salts
External additives on the surface of black toner as needed
Can be mixed. Generally, colloidal silica is about
Zinc stearate is present in an amount of 0.1 to about 2% by weight.
It is present in an amount of about 0.1% to about 2% by weight of the toner. these
Additives related to charge adjustment, mixability adjustment, conductivity adjustment, etc.
Function as described for color toner. The present invention
Black toner also uses a single chain end as an external additive.
At least about 80% of polymer chains terminated with droxy groups
Linear polymer alcohol containing a fully saturated hydrocarbon main chain containing
Can also be contained if necessary. Linear polymer alcohol is
General CH ₃(CH₂)_nCH₂OH, where n is
About 30 to about 300, preferably about 30 to about 50.
It This type of linear polymer alcohol is uniline (U
Nilin) generally from Peterlite Chemical Company
Available at. Linear polymer alcohols are generally
It is present in an amount of about 0.1 to about 1% by weight.

The black developer composition of the present invention generally comprises from about 1 to about 5 weight percent toner and from about 95 to about 99 weight percent carrier. However, the toner to carrier ratio can be varied so long as the objects of the invention are achieved. For example, the imaging device used in the method of the present invention may be replenished with a color developer containing about 65% by weight toner and about 35% by weight carrier. The triboelectric charge of black toner is generally about +
10 to about +30, preferably about +13 to about +18 microcoulombs / g, although the value can be outside the above range as long as the object of the invention is achieved. The particle size of the black toner is generally from about 8 to about 13 microns, preferably about 11 microns, by volume average diameter, although the values can be outside the above ranges as long as the objects of the invention are achieved. The coating of carrier particles for black developer is a powder coating in which a dry powder of the coating material is applied to the surface of the carrier particles and fused to the core by heating; the coating material is dissolved in a solvent and the resulting solution is a carrier. Solution coating, which is applied by tumbling to the surface; or flow in which carrier particles are blown into the air by a stream of air and a fog solution containing the coating material and solvent is repeatedly sprayed onto the carrier particles in the air until the desired coating amount is obtained. Obtained by any suitable method such as floor coating. The black toner is obtained by dry mixing resin, pigment and charge control agent, putting these materials in an extruder, melt mixing the mixture, extruding the material,
It may be prepared by methods such as extrusion, which is a continuous method that involves damping the extruded material into pellet form. The pellets are further size attenuated by grinding or jetting and then classified to the desired particle size. External additives such as linear polymeric alcohols, silica or zinc stearate are then mixed with the classified toner in a powder mixer. The toner and carrier are then mixed in conventional amounts, such as from about 0.5 to about 5% by weight toner and from about 95 to about 99.5% by weight carrier to form the two-color imaging of the present invention. A developer suitable for the method is obtained.

[0025]

【Example】

Example 1 90.5% by weight of Pliotone resin (available from Goodyear), 7.0% by weight of PV Fast Blue B2G-A pigment (available from Hoechst-Celanese), 2.0% by weight. % Bontron E-
A toner composition was prepared containing 88 aluminum compound charge control agent and 0.5% by weight cetyl pyridinium chloride charge control agent (available from Orient Chemical Co., Japan). The toner components were first dry mixed and then melt mixed in an extruder. The extruded strand was cooled, cut into small pellets, ground into toner particles and then classified to a narrow particle size distribution. The toner particles are 13.
It had a particle size (volume average) of 0 micron. continue,
Toner particles are silica particles in an amount of 0.3% by weight of the toner particles (Erojir R972, available from Degussa).
And dry mixed with zinc stearate (available from Synthetic Products) in an amount of 0.3% by weight of the toner particles. The carrier composition was prepared by using 80% by weight polymethylmethacrylate (E.P.I.) of Hoeganoes Steel Grit Core (available from Hoeganoes).
I. (Available from DuPont) and 20% by weight Vulcan carbon black (available from Cabot). The core was present in an amount of 99.2% by weight and the coating was present in an amount of 0.8% by weight. The coating was performed by a solution coating method from methyl ethyl ketone.

[0026]

Example 2 Developer composition, 3 parts by weight of the above toner and 1
Prepared by mixing together 00 parts by weight of the above carrier. Bontron E prepared in this way
A developer containing a -88 aluminum compound charge control agent was applied to a printer test apparatus containing one organic imaging member and two developer housings (this apparatus was used to print an imaging member containing a two color image and a three potential image). It can be developed in one pass by passing it through both developer housings, and the conductivity of the developer can be measured by the printer test apparatus at three potentials on the imaging member having voltages of -700V, -400V, and -100V, respectively. Operate with an electrostatic latent image to display a -100V image with Bontron E-8.
It was developed with a blue toner containing 8 and measured. The logarithm (base 10) of the conductivity (moe) of the developer was -9.0. For comparison purposes, the same measurements were performed on a developer having the same composition but the toner containing no cetyl pyridinium chloride and 3 wt% Bontron E-88 and 90 wt% Pliotone resin. Developers without cetyl pyridinium chloride showed low conductivity logarithmic values of -11.0. That is, the developer containing both cetyl pyridinium chloride and the aluminum compound charge control agent exhibited high conductivity, as suggested by the low absolute logarithmic value of the developer conductivity. Higher conductivity is generally desirable in developer compositions used in conductive development processes.

[0027]

Example 3 Four developers were prepared by preparing a toner as described in Example 1 containing a Bontron E-88 aluminum compound charge control agent. Each toner contained the amounts of pigment and external additives described in Example 1. Each toner contained 2 wt% Bontron E-88 aluminum compound charge control agent, 0.25 wt% cetyl pyridinium chloride, and 90.
75% by weight Pliotone; 2% by weight Bontron E-
88 aluminum compound charge control agent, 0.5 wt% cetyl pyridinium chloride, and 90.5 wt% pliotone; 3 wt% Bontron E-88 aluminum compound charge control agent, 0.25 wt% cetyl.
Pyridinium chloride, and 89.75 wt% Priotone; and 3 wt% Bontron E-88 aluminum compound charge control agent, 0.5 wt% cetyl.
It contained pyridinium chloride and 89.5% by weight of prionone. For comparison purposes, 3% by weight of Bontron E-88 aluminum compound charge control agent and 90%
A fifth toner was prepared containing wt% Pliotone. Each of the 5 toners was mixed with the carrier described in Example 1 to prepare 5 developer compositions.

Each developer was loaded into the printer test apparatus described in Example 2 and the toner to carrier ratio of the five developers was varied to include toner in each developer before peripheral edge field development occurs. The highest amount of concentration was measured. The edge field development occurred when the blue developer formed a blue halo surrounding the black image formed in the two color development process. A tri-potential image was formed on the imaging member in the above test apparatus. The color image was first developed with a blue developer containing a Bontron E-88 aluminum compound charge control agent and then the black image was developed with a black developer. The black developer was 2% by weight cetyl pyridinium chloride, 6% by weight Regal 330 carbon black (available from Cabot) and 92% by weight styrene / n-butyl methacrylate polymer (58% by weight styrene and 42% by weight). % Of n-butyl methacrylate). The toner particles had a particle size of 11.4 microns (volume average). Black carrier is 0.0
Hoeganoes Steel Core Coated with Polyvinyl Fluoride (Tedlar; Available from EI DuPont) Coating in Coating Amount to Contain 5 wt% Coating and 99.95 wt% Core (Carrier in Example 1 As mentioned above). The black toner and black carrier were mixed together in a relative amount of 3 parts by weight toner and 100 parts by weight carrier. The highest toner concentration possible in the blue developer containing no cetyl pyridinium chloride was 4.5% by weight of toner, which did not cause peripheral edge field development. On the other hand, in the blue developer containing both the Bontron E-88 aluminum compound charge control agent and cetyl pyridinium chloride, the maximum toner concentration as far as possible without causing the peripheral edge electric field development is:
8.6 wt% or more (2 wt% of Bontron E-8
8 and 0.25% by weight of cetyl pyridinium chloride), 6.5% by weight or more (toner containing 2% by weight of Bontron E-88 and 0.5% by weight of cetylpyridinium chloride), 6. 5 wt% or more (toner containing 3 wt% Bontron E-88 and 0.25 wt% cetyl pyridinium chloride), and 6.7 wt% or more (3 wt% Bontron E-88 and 0.5 wt%). % Toner containing cetyl pyridinium chloride). These results show that the toner to carrier ratio of the developer containing both the Bontron E-88 aluminum compound charge control agent and the cetyl pyridinium chloride is the toner to carrier ratio of the developer containing only the Bontron E-88 aluminum compound charge control agent. It suggests that it can be changed over a wider range. This wide range in which the toner to carrier ratio can be varied allows the developer to be adjusted to a range of temperature and relative humidity conditions in which development can occur without edge field development.

[0029]

[Embodiment 4] Each toner is a Bontron E as described in Embodiment 3.
-88 aluminum compound A charge control agent and four developers containing both cetyl pyridinium chloride,
Each was roll-milled for 30 minutes at a linear milling speed of 90 feet / minute (228.6 cm / minute), after which the charging characteristics of each toner were measured. For comparison purposes, the charging characteristics of a developer in which the toner contained a Bontron E-88 aluminum compound charge control agent but a cetyl pyridinium chloride as described in Example 3 were also measured after milling. The At value, containing both the Bontron E-88 aluminum compound charge control agent and cetylpyridinium chloride, is in the range of 75-83% μc / g;
The At value of the toner containing no cetyl pyridinium chloride was 70% μc / g, and Bontron E-88
It has been shown that toners containing both an aluminum compound charge control agent and cetyl pyridinium chloride can be more highly charged than toners without cetyl pyridinium chloride. At is a measure of triboelectric chargeability and is calculated from triboelectric charge in microcoulombs / g and toner concentration as follows: At = triboelectric charge (μc / g) × [toner concentration (%) +
1]

[0030]

[Embodiment 5] The toner described in Embodiment 3 is Bontron E.
A developer containing a -88 aluminum compound charge control agent, but not containing cetyl pyridinium chloride, and a toner whose mixing performance of four kinds of developers containing both a Bontron E-88 aluminum compound charge control agent and cetyl pyridinium chloride were compared. , Each developer 2.5
Toner concentrations of 100 parts by weight of toner to 100 parts by weight of carrier were loaded into a roll mill and fresh uncharged toner particles were added to the developer mixture at a toner level of 1 part by weight to develop the developer at 90 feet per minute (228 .6 cm / min) and the fresh toner was roll-milled until fully charged. Mixing was achieved in 15 seconds for four developers whose toners contained both a Bontron E-88 aluminum compound charge control agent and cetyl pyridinium chloride. On the other hand, the toner is Bontron E-8.
8 Aluminum compound containing charge control agent but cetyl
In the developer containing no pyridinium chloride, mixing was achieved in 30 seconds, indicating that the presence of both the Bontron E-88 aluminum compound charge control agent and cetylpyridinium chloride in the toner provided a more rapid mixability. It was

[0031]

Example 6 A toner composition was prepared as described in Example 1, except that the toner was 3 wt% Bontron E-84.
It contained a zinc compound charge control agent (available from Orient Chemical Co., Japan), 0.5 wt% cetyl pyridinium chloride, and 89.5 wt% pryotone. This toner was mixed with the carrier prepared as described in Example 1 and the mixing time of the resulting developer was measured by the method described in Example 5. The mixing time of this developer was 15 seconds.

[0032]

Example 7 Three developers were prepared by preparing the toner as described in Example 1, but using Bontron E-84 zinc compound charge control instead of Bontron E-88 aluminum compound charge control agent. Agent was included.
Each toner contained the amounts of pigment and external additives described in the toner of Example 1. Each toner contains 3 wt% of Bontron E-84 zinc compound charge control agent, 0.5%.
Wt% cetyl pyridinium chloride, and 8
9.5 wt% Pliotone; 2 wt% Bontron E
-84 Zinc compound charge control agent, 0.5 wt% cetyl
Pyridinium chloride, and 90.5 wt% pliotone; 2 wt% Bontron E-88 aluminum compound charge control agent, 0.5 wt% cetyl pyridinium chloride, and 90.5 wt% pliotone ( The toner pellets obtained from the extruder were converted to powder particles with an Alpine Fluid Bed Grinder). The toner particles had a particle size (volume average) of 13.0 microns. Each of the three toners is then mixed with a carrier as described in Example 1 and 3
A seed developer composition was obtained. Each developer was loaded into the printer test apparatus described in Example 2 and each of the three developers was subjected to varying toner to carrier ratios as described in Example 3 before peripheral edge field development occurred. The maximum amount of toner concentration that can be contained in the developer was measured. The maximum possible toner concentration in all three developers was 6.5% by weight or more, as far as the peripheral edge electric field development did not occur. In contrast, the developer of Example 3 containing only the Bontron E-88 aluminum compound charge control agent and no cetyl pyridinium chloride had a maximum toner concentration of 4.95% with no peripheral edge field development. .. These results show that the toner-to-carrier ratio of each developer containing both Bontron E-84 zinc compound charge control agent and cetyl pyridinium chloride is a toner to carrier ratio of the developer containing only Bontron E-88 aluminum compound charge control agent. It shows that it can be changed over a wider range than the ratio.

[0033]

Example 8 A developer was prepared by preparing a toner as described in Example 1, but using Bontron E-88.
Bontron E instead of aluminum compound charge control agent
A -84 zinc compound charge control agent was included, and cetyl pyridinium chloride was not included. 3 toner
Wt% Bontron E-84 Zinc Compound Charge Control Agent, 9
It contained 0% by weight of pliotone, and the amounts of pigment and external additives mentioned in the toner of Example 1. The toner was then mixed with the carrier as described in Example 1 to obtain a developer composition. This developer was loaded into the printer testing apparatus described in Example 2 and each developer was changed before changing the toner to carrier ratio of the developer as described in Example 3 to produce peripheral edge field development. The maximum amount of toner concentration that can be contained in was measured. With this developer, the maximum toner concentration possible was 6.5% by weight or more, which did not cause electric field development at the peripheral edge. On the other hand, Example 3 containing only the Bontron E-88 aluminum compound charge control agent and not containing cetyl pyridinium chloride.
Developer had a maximum toner concentration of 4.95% without edge field development. These results are Bontron E-8
The toner-to-carrier ratio of each developer containing a 4-zinc compound charge control agent can be varied over a wider range than the toner-to-carrier ratio of a developer containing only a Bontron E-88 aluminum compound charge control agent. Showing.

[0034]

Example 9 Four developers were prepared by the method described in Example 1 in which each toner contained both a Bontron E-88 aluminum compound charge control agent and distearyl dimethyl ammonium bisulfate. Each toner contained the amounts of pigment and external additives described in the toner of Example 1. Each toner contained 2 wt% Bontron E-88 aluminum compound charge control agent, 0.25 wt% distearyl dimethyl ammonium bisulfate (available from Hexel), and 90.75.
Wt% Pliotone; 2 wt% Bontron E-88
Aluminum compound charge control agent, 0.75 wt% distearyl dimethyl ammonium bisulfate, and 90.25 wt% pliotone; 3 wt% Bontron E-88 aluminum compound charge control agent, 0.2
5% by weight distearyldimethylammonium bisulfate, and 89.75% by weight pryotone;
3 wt% Bontron E-88 aluminum compound charge control agent, 0.75 wt% distearyl dimethyl ammonium bisulfate, and 89.25 wt%
It contained pliotone of. 3% by weight for comparison purposes
A fifth toner was prepared which contained the Bontron E-88 aluminum compound charge control agent of Nos. And 90% by weight of Pliotone. Then, each of the five types of toner is treated with Example 1
Five developer compositions were obtained by mixing with the carrier described in. Five types of developer are used at 90 ft / min (2
Roll milling was performed at a milling speed of 28.6 cm / min) for 30 minutes, and then the charging characteristics of each toner were measured. The At value of the four toners containing both Bontron E-88 aluminum compound charge control agent and distearyl dimethyl ammonium bisulfate was 82-90% μ.
c / g; on the other hand, the At value of the toner containing only the Bontron E-88 aluminum compound charge control agent is 70% μc / g, and the Bontron E-88 aluminum compound charge control agent and distearyl dimethyl ammonium It has been shown that toners containing both bisulfates can be more highly charged than toners containing no distearyl dimethyl ammonium bisulfate.

[0035]

EXAMPLE 10 The toner described in Example 9 contains Bontron E-88 aluminum compound charge control agent but does not contain distearyl dimethyl ammonium bisulfate. The developer and toner are Bontron E-88.
Contains both aluminum compound charge control agent and distearyl dimethyl ammonium bisulfate 4
Each developer mix was loaded into a roll mill at a toner concentration of 2.5 parts by weight of toner to 100 parts by weight of carrier, and the developer mixture was loaded with fresh uncharged toner particles. Additions were made in parts by weight of toner and the developer was measured by roll milling at 90 ft / min (228.6 cm / min) until the fresh toner was fully charged. Mixing was achieved in 15 seconds for the four developers whose toners contained both Bontron E-88 aluminum compound charge control agent and distearyl dimethyl ammonium bisulfate. In contrast, in a developer in which the toner contained a Bontron E-88 aluminum compound charge control agent but no distearyl dimethyl ammonium bisulfate, mixing was achieved in 30 seconds, and the Bontron E-88 aluminum compound in the toner was achieved. It was shown that the presence of both the compound charge control agent and distearyl dimethyl ammonium bisulfate provided more rapid miscibility.

Front Page Continuation (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication location G03G 15/01 117 Z 7818-2H G03G 9/08 375 (72) Inventor Michael El Grande New York, USA 14522 Palmyra Root 21 2786 (72) Inventor William H. Hollingbo Junia, New York, USA 14580 Webster Kanoe Birch Lane 722 (72) Inventor Roger N Chiccarelli, New York, USA 14618 Rochester Hibiscus Drive 145

Claims (2)

[Claims] 1. A resin; a colorant; (a) 3,5-di-t-
A mixture of a zinc butylsalicylate compound and an alkylpyridinium halide, (b) a mixture of a 3,5-di-t-butylsalicylate zinc compound and a distearyl dimethyl ammonium methyl sulfate, (c)
Mixture of 3,5-di-t-butylsalicylate zinc compound and distearyl dimethyl ammonium bisulfate, (d) Mixture of 3,5-di-t-butylsalicylate aluminum compound and alkyl pyridinium halide, (e) 3 , 5-di-t-butylsalicylic acid aluminum compound and distearyl dimethyl ammonium methyl sulphate mixture, (f) 3,5
-A mixture of an aluminum di-t-butylsalicylate compound and distearyl dimethyl ammonium bisulfate, and a charge control additive selected from the group consisting of these mixtures; a colloidal silica external additive; and a fatty acid metal salt external additive A toner composition comprising: 2. An image forming member is charged to form a latent image including high, medium and low potential regions on the image forming member,
Low potential region is represented by resin; coloring agent; (a) 3,5-di-t-
Zinc butylsalicylate compound, (b) 3,5-di-t-
A mixture of a zinc butylsalicylate compound and an alkylpyridinium halide, (c) a mixture of a zinc compound of 3,5-di-t-butylsalicylate and a distearyl dimethyl ammonium methyl sulfate, (d)
Mixture of 3,5-di-t-butylsalicylic acid zinc compound and distearyl dimethyl ammonium bisulfate, (e) Mixture of 3,5-di-t-butylsalicylic aluminum compound and alkylpyridinium halide, (f) 3 , 5-di-t-butylsalicylic acid aluminum compound and distearyl dimethyl ammonium methyl sulphate mixture, (g) 3,5-
A mixture of an aluminum di-t-butylsalicylate compound and distearyl dimethyl ammonium bisulfate, and a charge control additive selected from the group consisting of these mixtures; a colloidal silica external additive; and a fatty acid metal salt external additive. Developing with a developer containing the toner of the first color containing and carrier, and subsequently developing the high potential region with the developer containing the toner of the second color and carrier, transferring the developed two-color image to the substrate, and A method for forming a two-color image, wherein the image is permanently fixed to the substrate according to the above.