JP6075151B2 - Image forming method and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming method and an image forming apparatus.

Color image formation by electrophotography, for example, is intended for use in general offices such as color printers and color copies, and has entered the commercial printing field called desktop publishing (DTP) and on-demand publishing. Has been done. In the field of commercial printing, an electrophotographic image forming apparatus is suitably used as a machine for speedy printing of small lots of thousands to tens of thousands of sheets without causing plate.
By the way, most of full-color image forming apparatuses are configured to reproduce all colors using three colors of yellow, magenta and cyan, which are so-called three primary colors. Various colors are realized by overlapping colors.

  However, in such color image formation, only a color gamut in accordance with the hue, saturation, and lightness specific to the mounted toner such as yellow, magenta, and cyan can be developed. For example, the saturation generally increases as the toner adhesion amount increases to a certain range, but reaches saturation when the toner adhesion amount exceeds a certain value, and thereafter gradually decreases.

  In order to obtain a wider color gamut, toners having hue angles similar to those of the three primary colors yellow, magenta, and cyan, such as high saturation yellow, high saturation magenta, and high saturation cyan, and high saturation and lightness are used separately. (For example, refer to Patent Documents 1 to 3).

  However, such an image forming apparatus has a problem that the size and complexity of the apparatus cannot be avoided due to an increase in the number of types of toner to be mounted.

JP 2010-170027 A JP 2011-150335 A JP2012-123201A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming method and an image forming apparatus capable of obtaining color development in an extremely wide color gamut.

The image forming method of the present invention reacts with a primary color toner image formed by a toner containing a colorant of a variable dye (A) on an image support and the colorant of the variable dye (A). By overlapping and heat-fixing a color change toner image formed by a toner containing a color change agent that develops a different visible color (LA) from the dye (A),
An image forming method for obtaining a visible image having an image portion that develops at least the visible color (LA) ,
The discoloring agent comprises a metal complex represented by the following general formula (1),
The colorant of the variable dye (A) is a yellow colorant represented by the following general formula (Y), a magenta colorant represented by the following general formula (M), or the following general formula (C). It is characterized by being a cyan colorant .

[Wherein, M represents a divalent metal atom, R ¹ represents a hydrogen atom or a monovalent organic group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic ring. Group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or cyano group, R ³ represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group or A ring group is shown. ]

[Wherein R ¹¹ and R ¹² each represents a hydrogen atom or a monovalent organic group, R ¹³ represents an alkyl group or an aryl group which may have a substituent, and Z represents two An atomic group necessary for forming a 5-membered or 6-membered aromatic ring with a carbon atom is shown. ]

[Wherein R ²¹ represents a hydrogen atom, a halogen atom or a monovalent organic group, and R ²² represents an optionally substituted aromatic carbocyclic group or an optionally substituted aromatic heterocyclic group. , R ²³ represents the following general formula (2) or (3). X represents a methine group or a nitrogen atom. ]

[In general formula (2), X ′ represents a carbon atom or a nitrogen atom, and Y represents an atomic group necessary for forming a nitrogen-containing aromatic heterocyclic ring. Further, in the general formula (3), W represents an atomic group necessary to form two aromatic carbocyclic or aromatic heterocyclic ring with the carbon atom, R ²⁴ represents an alkyl group. ]

[Wherein R ³¹ and R ³² each represent a substituted or unsubstituted aliphatic group, and R ³³ represents a monovalent organic group. n represents an integer of 0 to 4, and when n is 2 or more, the plurality of R ³³ may be the same or different. R ³⁴ , R ³⁵ and R ³⁶ all represent an alkyl group, but R ³⁴ , R ³⁵ and R ³⁶ may be the same or different. However, R ³⁵ and R ³⁶ is an alkyl group having 3 to 8 carbon atoms. ]

In the image forming method of the present invention, on the image support,
A yellow toner image formed by a toner containing a yellow colorant represented by the general formula (Y);
A magenta toner image formed by a toner containing a magenta colorant represented by the general formula (M);
A cyan toner image formed by a toner containing a cyan colorant represented by the general formula (C);
It reacts with any of the yellow colorant, the magenta colorant and the cyan colorant, respectively, and a visible color different from the yellow (high chroma yellow), a visible color different from the magenta (high chroma magenta), and the cyan It is preferable that the toner image for color change formed by the toner containing a color change agent that develops a different visible color (high chroma cyan) is superposed and heat-fixed.

An image forming apparatus according to the present invention includes a charging unit that charges a photoreceptor,
Exposure means for forming an electrostatic latent image by exposing a charged photoreceptor; and
A plurality of image forming units having at least developing means for developing the electrostatic latent image with toner;
An image forming apparatus comprising transfer means for transferring a developed toner image to an image support and fixing means for heating and fixing the toner image on the image support,
The image forming unit reacts with a primary color image forming unit that develops with a toner containing a colorant of a variable dye (A) as a toner, and the colorant of the variable dye (A) as a toner. And a color changer image forming unit that develops with a toner containing a color changer that develops a different visible color (LA).
The primary color toner image formed by the toner containing the colorant of the variable dye (A) on the image support and the visible color different from the variable dye (A) by reacting with the colorant of the variable dye (A). A visible image having an image portion that develops at least the visible color (LA) is obtained by superimposing and fixing the toner image for color change formed with a toner containing a color changing agent that develops the color (LA). It is,
The discoloring agent comprises a metal complex represented by the following general formula (1),
The colorant of the variable dye (A) is a yellow colorant represented by the following general formula (Y), a magenta colorant represented by the following general formula (M), or the following general formula (C). It is characterized by being a cyan colorant .

[Wherein, M represents a divalent metal atom, R ¹ represents a hydrogen atom or a monovalent organic group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic ring. Group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or cyano group, R ³ represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group or A ring group is shown. ]

[Wherein R ¹¹ and R ¹² each represents a hydrogen atom or a monovalent organic group, R ¹³ represents an alkyl group or an aryl group which may have a substituent, and Z represents two An atomic group necessary for forming a 5-membered or 6-membered aromatic ring with a carbon atom is shown. ]

[Wherein R ²¹ represents a hydrogen atom, a halogen atom or a monovalent organic group, and R ²² represents an optionally substituted aromatic carbocyclic group or an optionally substituted aromatic heterocyclic group. , R ²³ represents the following general formula (2) or (3). X represents a methine group or a nitrogen atom. ]

[In general formula (2), X ′ represents a carbon atom or a nitrogen atom, and Y represents an atomic group necessary for forming a nitrogen-containing aromatic heterocyclic ring. Further, in the general formula (3), W represents an atomic group necessary to form two aromatic carbocyclic or aromatic heterocyclic ring with the carbon atom, R ²⁴ represents an alkyl group. ]

[Wherein R ³¹ and R ³² each represent a substituted or unsubstituted aliphatic group, and R ³³ represents a monovalent organic group. n represents an integer of 0 to 4, and when n is 2 or more, the plurality of R ³³ may be the same or different. R ³⁴ , R ³⁵ and R ³⁶ all represent an alkyl group, but R ³⁴ , R ³⁵ and R ³⁶ may be the same or different. However, R ³⁵ and R ³⁶ is an alkyl group having 3 to 8 carbon atoms. ]

In the image forming apparatus of the present invention, a plurality of the primary color image forming units are provided,
The primary color image forming unit is a yellow image forming unit that develops with toner containing a yellow colorant represented by the general formula (Y) as a toner, and the toner is represented by the general formula (M). A magenta image forming unit for developing with a toner containing a magenta colorant, and a cyan image forming unit for developing with a toner containing a cyan colorant represented by the above general formula (C) as the toner. It is preferable to include.

According to the image forming method of the present invention, the primary color formed only from the primary color toner image formed by the toner containing the colorant of the variable dye (A) by superimposing the primary color toner image on the primary color toner image. Since an image portion that develops a visible color (LA) different from that of the image portion can be formed, it is possible to obtain color development in a very wide color gamut in the obtained visible image.
In particular, when a plurality of colors are used as the colorant of the variable dye (A), it is possible to obtain a color in a very wide color gamut by using a small amount of toner.

It is sectional drawing for description for demonstrating the image forming method of this invention typically. 1 is a cross-sectional view illustrating an example of a configuration of an image forming apparatus according to the present invention.

  Hereinafter, the present invention will be specifically described.

  As shown in FIG. 1A, the image forming method of the present invention is formed on an image support P with a toner containing a colorant of a variable dye (A) (hereinafter also referred to as “colored toner”). The primary color toner image 2 and a color change agent that reacts with the colorant of the variable dye (A) to develop a specific visible color (LA) different from the variable dye (A) (hereinafter, “metal source color change agent”) 1 (b)), the toner image 5 for discoloration formed with a toner containing toner (hereinafter also referred to as "MS toner") is superimposed and heat-fixed, as shown in FIG. An image portion (hereinafter also referred to as a “light image portion”) 8 that develops a specific visible color (LA), which is formed from a portion where at least the primary color toner image 2 and the color change toner image 5 are overlapped. Preferably, with the light image portion 8 and possible Dye image portions to develop the color of the (A) (hereinafter, also referred to as "primary color image portion".) The image forming method for obtaining a visible image 1 and a 9.

In the image forming method of the present invention, the primary color image portion 9 contains the colorant of the variable dye (A) and does not contain the metal source discolorant. Therefore, the hue, saturation, and It is colored with visible lightness.
On the other hand, the light image portion 8 is heated in a state where the colorant of the variable dye (A) and the metal source color changer are in contact with each other by heat fixing, and the colorant of the variable dye (A) and the metal source color changer react. The reaction product, and as a result, the visible color inherent to the colorant of the variable dye (A) differs from the color of the metal source colorant and the colorant of the variable dye (A). Color is generated in a specific visible color (LA) with a saturation and brightness different from those obtained by mixing colors with a subtractive color method. The visible color (LA) has a hue equivalent to that of the variable dye (A), and has a higher brightness and saturation than the variable dye (A). That is, when the variable dye (A) is yellow, the specific visible color (LA) is so-called high saturation yellow (light yellow), and when the variable dye (A) is magenta, the specific visible color (LA) is so-called. When the saturation is high saturation magenta (light magenta) and the variable dye (A) is cyan, the specific visible color (LA) is so-called high saturation cyan (light cyan).
In the present invention, unless otherwise specified, the hue, saturation, and brightness are used to compare whether the toner adhesion amount is the same or different when the toner adhesion amount is 4 g / m ² .
In addition, the image part which contains a metal source color change agent and does not contain the colorant of the variable dye (A) is visually recognized as a colorless or very light color that is difficult to visually recognize.

In the image forming method of the present invention, a full-color visible image can be formed. In particular, a normal three-color (yellow, magenta, cyan) colored toner, an MS toner for coloring the high-saturation colors (light yellow, light magenta, and light cyan) related to the three colors, and a black toner were used. By using the five-color developing method, a combination of seven colors (yellow, magenta, cyan, light yellow, light magenta, light cyan, and black) can be output to form a full-color visible image.
That is, a yellow toner image formed by a toner containing a yellow colorant, a magenta toner image formed by a toner containing a magenta colorant, and a cyan toner formed by a toner containing a cyan colorant For discoloration formed by toner containing an image and a metal source discolorant that reacts with any of these yellow, magenta and cyan colorants to produce light yellow, light magenta and light cyan, respectively, with high saturation and lightness. It is preferable to have a configuration in which the toner image is superimposed and heated and fixed.
In such an image forming method, the light image portion 8 is colored in light yellow, light magenta, light cyan, or a color obtained by mixing two or more of these colors by a subtractive color method.

The image forming apparatus used in the image forming method of the present invention will be described below.
FIG. 2 is an explanatory sectional view showing an example of the configuration of the image forming apparatus of the present invention.
This image forming apparatus is a tandem type color image forming apparatus of a fixing system in which the primary color toner image 2 and the color change toner image 5 are superposed in an unfixed state and heated and fixed together. .
Specifically, an MS toner image forming unit 20S (color change agent image forming unit) that forms a toner image 5 for color change and a primary color toner image forming unit that forms a toner image 2 of primary colors of yellow, magenta, and cyan, respectively. 20Y, 20M, and 20C (primary color image forming units), a black toner image forming unit 20Bk that forms a black toner image, and each of the toner image forming units 20S, 20Y, 20M, 20C, and 20Bk. The image forming apparatus includes an intermediate transfer unit 10 that transfers a toner image onto an image support P, and a fixing device 26 that presses and fixes the image support P while heating.
In this image forming apparatus, the toner image forming units 20S, 20Y, 20M, 20C, and 20Bk are arranged in this order from the upstream to the downstream in the circulation direction of the intermediate transfer member 16 that constitutes the intermediate transfer unit 10.

  Each of the toner image forming units 20S, 20Y, 20M, 20C, and 20Bk includes the photoreceptors 11S, 11Y, 11M, 11C, and 11Bk that are electrostatic latent image carriers, and the photoreceptors 11S, 11Y, 11M, 11C, and 11Bk. An electrostatic latent image having a desired shape is formed on the charging means 23S, 23Y, 23M, 23C, and 23Bk for applying a uniform potential to the surface and the uniformly charged photoreceptors 11S, 11Y, 11M, 11C, and 11Bk. The exposure means 22S, 22Y, 22M, 22C, and 22Bk, and the MS toner, the colored toner of each color, or the black toner are conveyed onto the photoreceptors 11S, 11Y, 11M, 11C, and 11Bk to visualize the electrostatic latent image. Development means 21S, 21Y, 21M, 21C, 21Bk for forming a color change toner image 5, a primary color toner image 2 or a black toner image of each color, and a sensitivity after primary transfer Body 11S, 11Y, an image forming unit with 11M, 11C, cleaning means 25S for recovering residual toner remaining on 11Bk, 25Y, 25M, 25C, and 25Bk.

The intermediate transfer unit 10 receives the color change toner image 5 formed by the intermediate transfer member 16 and the toner image forming units 20S, 20Y, 20M, 20C, and 20Bk, the primary color toner image 2 of each color, or the black toner image. Toner images for color change transferred onto the intermediate transfer body 16 by the primary transfer rollers 13S, 13Y, 13M, 13C, and 13Bk for transferring to the intermediate transfer body 16 and the primary transfer rollers 13S, 13Y, 13M, 13C, and 13Bk. 5. A secondary transfer roller 13A that transfers the primary color toner image 2 or the black toner image of each color onto the image support P, and a cleaning unit 12 that collects residual toner remaining on the intermediate transfer body 16.
The intermediate transfer body 16 has an endless belt shape that is stretched by a plurality of support rollers 16a to 16d and is rotatably supported.

  The fixing device 26 is provided in a state in which a pair of heat and pressure rollers 27 and 28 are in pressure contact with each other and a nip portion N is formed in the pressure contact portion.

(Image forming method)
In the image forming apparatus as described above, first, in each of the toner image forming units 20S, 20Y, 20M, 20C, and 20Bk, charging means 23S, 23Y, 23M, and 23C are provided on the photoreceptors 11S, 11Y, 11M, 11C, and 11Bk. , 23Bk and electrostatic exposure images are formed by exposure by the exposure means 22S, 22Y, 22M, 22C, 22Bk, and the electrostatic latent images are formed in the development means 21S, 21Y, 21M, 21C, 21Bk. By developing with toner, a color change toner image 5, a primary color toner image 2 or a black toner image is formed, and the primary transfer rollers 13S, 13Y, 13M, 13C, and 13Bk change the color on the intermediate transfer body 16. Toner image 5, primary toner image 2 of each color, or black toner image is transferred in this order, and an intermediate transfer member Superimposed on 6 toner powder layer by unfixed toner is formed.
On the other hand, the image support P accommodated in the paper feed cassette 41 is fed by the paper feed transport means 42 and transported by a plurality of paper feed rollers 44a, 44b, 44c, 44d and registration rollers 46, and is subjected to secondary transfer. The toner powder layer on the intermediate transfer member 16 is collectively transferred onto the image support P by the roller 13A. Thereafter, the toner powder layer transferred onto the image support P is fixed by pressurization and heating in the fixing device 26, whereby a visible image 1 is formed, and then discharged to the outside by the discharge roller 47. And placed on the paper discharge tray 40.

The toner powder layer transferred onto the image support P is a black toner image, a cyan toner image, a magenta toner image, a yellow toner image, and a color change image on the image support P from the image support P side. The toner images 5 are superposed in this order.
The toner image 5 for color change has a shape covering a portion where a light image portion is to be formed.
In addition, the image portion obtained by superimposing the color change toner image on the black toner image and being heat-fixed is obtained by mixing the color of the metal source color change agent and the color of the black colorant by a color reduction method. The resulting color will be developed. Since the color of the metal source color changing agent is nearly colorless, black color is developed according to the black colorant used. Therefore, it is not necessary to superimpose the color change toner image on the black toner image.

[Fixing conditions]
The fixing condition by the fixing device 26 is that the heating temperature is 150 to 230 ° C., preferably 160 to 190 ° C., and the nip time is 10 to 300 msec.
The heating temperature in the fixing device 26 refers to the surface temperature of the heating and pressure roller 27 with which the toner powder layer transferred onto the image support P comes into contact.
The nip time is calculated from the length of the nip portion N in the conveyance direction (mm) / linear velocity (mm / sec) × 1000.

The photosensitive members 11S, 11Y, 11M, 11C, and 11Bk after the toner image 5 for color change, the toner image 2 of each primary color, or the black toner image is transferred to the intermediate transfer member 16 are cleaned by the cleaning means 25S, 25Y, and 25M. , 25C, 25Bk to remove the toner remaining on the photoreceptors 11S, 11Y, 11M, 11C, 11Bk, and then to form the next color change toner image 5, the primary color toner image 2 of each color, or the black toner image. Provided.
On the other hand, the intermediate transfer body 16 after the toner powder layer is transferred onto the image support P by the secondary transfer roller 13A is removed after the toner remaining on the intermediate transfer body 16 is removed by the cleaning means 12. Used for intermediate transfer of toner powder layer.

The visible image 1 obtained by being fixed by the fixing device 26 has a primary color image portion 9, a light image portion 8 and, if necessary, a black image portion.
In the primary color image portion 9, colors specific to the primary colorants of yellow, magenta, and cyan used are simply developed, or colors obtained by mixing these two or more colors by a subtractive color method. Is done.
In the light image portion 8, the yellow, magenta and cyan primary colorants used react with the metal source discolorant, and light yellow, light magenta or light cyan, or two or more of these colors are reduced by the color reduction method. The color is obtained by mixing the colors.

  According to such an image forming apparatus, the metal source color changing agent is caused to react in common with the colorants of each primary color by the MS toner without using three kinds of toners of light yellow toner, light magenta toner, and light cyan toner. As a result, it is possible to obtain a color in an extremely wide color gamut similar to the case where light yellow, light magenta, and light cyan toners are used.

[MS toner]
The MS toner may be a so-called clear toner containing no colorant and containing a metal source color changing agent. Specifically, the toner particles include a binder resin and a metal source discoloring agent, and the toner particles further include magnetic powder, a release agent, a charge control agent, and the like as desired. Can do.

  The content ratio of the metal source color changing agent in the toner particles is preferably 1 to 15 parts by mass, more preferably 4 to 9 parts by mass with respect to 100 parts by mass of the binder resin.

[Metal source discoloring agent]
The metal source color changing agent constituting the MS toner can be made of the metal complex represented by the general formula (1).
In the general formula (1) indicating a metal source color changing agent, M represents a divalent metal atom, preferably a divalent transition metal atom.
The group M includes, among divalent transition metal atoms, a yellow colorant represented by the general formula (Y), a magenta colorant represented by the general formula (M), and the general formula (C). From the viewpoint of forming a metal complex with the colorant of any of the variable dyes (A) of the cyan colorant represented by formula (I) and the stability of the color tone of the light image portion in the finally obtained visible image, nickel atoms , A copper atom and a zinc atom are preferable, and a copper atom is most preferable.

In the general formula (1), R ¹ represents a hydrogen atom or a monovalent organic group.
Examples of the monovalent organic group representing the group R ¹ include an alkyl group (for example, methyl group, ethyl group, propyl group, i-propyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group). Group, tetradecyl group, pentadecyl group, chloromethyl group, trifluoromethyl group, trichloromethyl group, tribromomethyl group, pentafluoroethyl group, methoxyethyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), Alkenyl groups (such as vinyl and allyl groups), alkynyl groups (such as ethynyl and propargyl groups), aryl groups (such as phenyl, naphthyl, p-nitrophenyl, p-fluorophenyl, and p-methoxyphenyl) Group), heterocyclic group (for example, furyl group, thienyl group, pyridyl group, Dazyl group, pyrimidyl group, pyrazyl group, triazyl group, imidazolyl group, pyrazolyl group, thiazolyl group, benzoimidazolyl group, benzoxazolyl group, quinazolyl group, phthalazyl group, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.) Alkoxycarbonyl groups (for example, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl groups (for example, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl groups ( For example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl Group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexyl group) Carbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, benzoyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), carbamoyl group (eg aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dode Ruaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecyl) Sulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.) ), Arylsulfonyl groups (phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), cyano groups and the like.

The group R ¹ is preferably a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an alkoxycarbonyl group, an acyl group, a carbamoyl group, or a cyano group, and most preferably a hydrogen atom, an alkyl group, an aryl group A group, a heterocyclic group, and a cyano group. The monovalent organic groups exemplified as these preferable ones may be unsubstituted or may have a substituent.

In the general formula (1), R ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfinyl group, or an alkylsulfonyl. A group, an arylsulfonyl group or a cyano group;

Specific examples of each organic group representing the group R ² are illustrated below.
Examples of the alkyl group include methyl, ethyl, propyl, i-propyl, t-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl, pentadecyl, chloromethyl, trimethyl. Examples thereof include a fluoromethyl group, a trichloromethyl group, a tribromomethyl group, a pentafluoroethyl group, and methoxyethyl.
Examples of the alkenyl group include a vinyl group and an allyl group.
Examples of the alkynyl group include ethynyl group and propargyl group.
Examples of the aryl group include a phenyl group, a naphthyl group, a p-nitrophenyl group, a p-fluorophenyl group, and p-methoxyphenyl.
Heterocyclic groups include furyl, thienyl, pyridyl, pyridazyl, pyrimidyl, pyrazyl, triazyl, imidazolyl, pyrazolyl, thiazolyl, benzoimidazolyl, benzoxazolyl, quinazolyl, phthalazyl Pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group and the like.
Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, an octyloxycarbonyl group, and a dodecyloxycarbonyl group.
Examples of the aryloxycarbonyl group include a phenyloxycarbonyl group and a naphthyloxycarbonyl group.
The carbamoyl group includes an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a propylaminocarbonyl group, a pentylaminocarbonyl group, a cyclohexylaminocarbonyl group, an octylaminocarbonyl group, a 2-ethylhexylaminocarbonyl group, and a dodecylaminocarbonyl group. , Phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group and the like.
The sulfamoyl group includes aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthyl. An aminosulfonyl group, 2-pyridylaminosulfonyl group, etc. are mentioned.
Examples of the sulfinyl group include a methylsulfinyl group, an ethylsulfinyl group, a butylsulfinyl group, a cyclohexylsulfinyl group, a 2-ethylhexylsulfinyl group, a dodecylsulfinyl group, a phenylsulfinyl group, a naphthylsulfinyl group, and a 2-pyridylsulfinyl group.
Examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a cyclohexylsulfonyl group, a 2-ethylhexylsulfonyl group, and a dodecylsulfonyl group.
Examples of the arylsulfonyl group include phenylsulfonyl, naphthylsulfonyl, 2-pyridylsulfonyl and the like.

The group R ² is preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxycarbonyl group, or a cyano group, and most preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, or a cyano group. is there. The monovalent organic groups exemplified as these preferable ones may be unsubstituted or may have a substituent.

In the general formula (1), R ³ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group.

Specific examples of each organic group representing the group R ³ are exemplified below.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an i-propyl group, a t-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.
Examples of the alkenyl group include a vinyl group and an allyl group.
Examples of the alkynyl group include ethynyl group and propargyl group.
Examples of the aryl group include a phenyl group, a naphthyl group, a p-nitrophenyl group, a p-fluorophenyl group, and a p-methoxyphenyl group.
Heterocyclic groups include furyl, thienyl, pyridyl, pyridazyl, pyrimidyl, pyrazyl, triazyl, imidazolyl, pyrazolyl, thiazolyl, benzoimidazolyl, benzoxazolyl, quinazolyl, phthalazyl Pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group and the like.

The group R ³ is preferably an alkyl group, an alkenyl group, an alkynyl group or an aryl group, and most preferably an alkyl group or an aryl group. The monovalent organic groups exemplified as these preferable ones may be unsubstituted or may have a substituent.

In the general formula (1), R ¹ and R ² , or R ² and R ³ may be connected to each other to form a 5- to 6-membered ring.

Furthermore, in this general formula (1), it is more preferable that either R ¹ or R ² is an electron-withdrawing group, and the total of σρ values of R ¹ and R ² is 0.2-2. Most preferably, it is zero.
Here, the “electron-withdrawing group” is a substituent whose substituent constant ρ according to the Hammett rule can take a positive value, and the substituent constant of the Hammett rule is a meta-substituted product of an aromatic compound. Alternatively, in a para-substituted product, Hammett's formula that is established when the reaction rate constants of an unsubstituted compound and a compound having a substituent are k0 and k, respectively, is defined as σ in log (k / k0) = ρσ.
In the Hammett equation, ρ = 1 is the dissociation reaction of benzoic acid and its derivatives in an aqueous solution at 25 ° C. Regarding Hammett's substituent constants, see Journalof Medicinal Chemistry, 1973, Vol. 16, no. 11, 1207-1216 etc. can be referred to.

Specific examples of the electron-withdrawing group include an alkyl group having a substituent (for example, a halogen-substituted alkyl group), an alkenyl group having a substituent (for example, a cyanovinyl group), an unsubstituted or substituted alkynyl group (for example, a trivalent group). Fluoromethylacetylenyl group, cyanoacetylenyl group, etc.), substituted aryl group (eg, cyanophenyl), unsubstituted or substituted heterocyclic group (eg, pyridyl group, triazinyl group, benzoxazolyl) Group), halogen atom, cyano group, acyl group (eg acetyl group, trifluoroacetyl group, formyl group etc.), thioacetyl group (eg thioacetyl group, thioformyl group etc.), oxalyl group (eg methyl oxalyl group etc.), oxy An oxalyl group (eg, etoxalyl group), a thiooxalyl group (eg, ethyl) Thiooxalyl group etc.), oxamoyl group (eg methyl oxamoyl group etc.), oxycarbonyl group (eg ethoxycarbonyl group etc.), carboxyl group, thiocarbonyl group (eg ethylthiocarbonyl group etc.), carbamoyl group, thiocarbamoyl group, Sulfonyl, sulfinyl, oxysulfonyl (eg, ethoxysulfonyl), thiosulfonyl (eg, ethylthiosulfonyl), sulfamoyl, oxysulfinyl (eg, methoxysulfinyl), thiosulfinyl (eg, methylthiosulfinyl) Group), sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group (eg N-acetylimino group etc.), N-sulfonylimino group (eg N-methanesulfonylimino group etc.), Cyano ethylene group, an ammonium group, a sulfonium group, a phosphonium group, pyrylium group, such as immonium group.
Among these, an alkyl group having a substituent, an aryl group having a substituent, a cyano group, an acyl group, an oxycarbonyl group, a nitro group, and a cyano group are preferable. Specifically, a cyano group, a nitro group, and trichloromethyl are included. A group, a dichloromethyl group, a chloromethyl group, a tribromomethyl group, a dibromomethyl group, a bromomethyl group, an alkoxyacyl group, an acyl group, and an aromatic ring substituted with these organic groups are preferable.

Such a metal source color changing agent represented by the general formula (1) is obtained by synthesizing a compound represented by the following general formula (4) and reacting the compound with a compound containing a divalent metal. It is preferable that
Here, the synthesis method of these metal complexes can be synthesized according to the method described in “Chelate Chemistry (5) Coordination Chemistry Experimental Method [I] (Edited by Nanedo)” and the like. The compounds containing divalent metals used for this synthesis include nickel chloride, nickel acetate, magnesium chloride, calcium chloride, barium chloride, zinc chloride, zinc acetate, titanium (II) chloride, iron (II) chloride, Examples include copper chloride (II), cobalt chloride, manganese chloride (II), lead chloride, lead acetate, mercury chloride, and mercury acetate. As described above, the yellow colorant represented by the above general formula (Y) A magenta colorant represented by the above general formula (M) and a cyan colorant represented by the above general formula (C) to form a metal complex with any colorant of the variable dye (A); From the viewpoint of the stability of the color tone of the light image portion in the finally obtained visible image, zinc chloride, zinc acetate, nickel chloride, nickel acetate, copper chloride and copper acetate are preferred, and copper acetate is most preferred. .

[Wherein, R ¹ represents a hydrogen atom or a monovalent organic group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkoxycarbonyl group, or an aryloxycarbonyl group. Carbamoyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or cyano group, R ³ represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group. ]

  Specific examples of the metal source color changing agent represented by the general formula (1) include compounds represented by the following formulas (1-1) to (1-14).

[Binder resin]
The binder resin constituting the MS toner is not particularly limited, but those having a tetrahydrofuran (THF) insoluble content of less than 20% with respect to 100% of the toner can be preferably used. When the THF-insoluble content is excessive, the reaction between the metal source color change agent contained in the MS toner and the colorant of the variable dye (A) contained in the color toner is less likely to occur at the time of heat fixing. There is a possibility that a specific visible color (LA) cannot be expressed in the visible image.

  Specific examples of the binder resin include, for example, vinyl polymers such as styrene resins, acrylic resins, styrene-acrylic copolymer resins, olefin resins, polyester resins, silicone resins, amide resins, and epoxy resins. Can be mentioned. These can be used alone or in combination of two or more.

〔Release agent〕
The release agent is not particularly limited. For example, polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, carnauba wax, sazol wax, rice wax, candelilla wax, jojoba oil wax , Beeswax wax and the like can be used.
The content ratio of the release agent in the toner particles is usually 0.5 to 5 parts by mass, preferably 1 to 3 parts by mass with respect to 100 parts by mass of the binder resin. If the content of the release agent is less than 0.5 parts by mass with respect to 100 parts by mass of the binder resin, a sufficient offset prevention effect may not be obtained, whereas, with respect to 100 parts by mass of the binder resin. If it is larger than 5 parts by mass, the resulting MS toner may have low translucency and color reproducibility.

[Method for producing MS toner]
The method for producing the MS toner is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method.
Among these, it is preferable to employ an emulsion aggregation method from the viewpoints of particle size uniformity, shape controllability, and ease of forming a core-shell structure, which are advantageous for high image quality and high charge stability.
In the emulsion aggregation method, a dispersion of binder resin fine particles (hereinafter also referred to as “resin fine particles”) dispersed by a surfactant or a dispersion stabilizer is used as a toner such as fine particles of a metal source discoloring agent as necessary. By mixing with a dispersion of particle constituents and adding an aggregating agent to agglomerate until the desired toner particle size is obtained, and thereafter or simultaneously with the agglomeration, the resin fine particles are fused together to control the shape. This is a method for forming toner particles.
Here, the resin fine particles may be composite particles formed of a plurality of layers having two or more layers made of resins having different compositions.
The resin fine particles can be produced, for example, by an emulsion polymerization method, a miniemulsion polymerization method, a phase inversion emulsification method, or the like, or can be produced by combining several production methods. Among them, the miniemulsion polymerization method is preferably used.
As a method of incorporating a metal source color change agent into the toner particles, the resin fine particles may contain a metal source color change agent, or a dispersion of metal source color change agent fine particles comprising only the metal source color change agent is separately prepared. The metal source color changer fine particles may be aggregated together when the resin fine particles are aggregated.
Further, when the toner particles are configured to have a core-shell structure, resin fine particles having different compositions may be added at a time difference during aggregation and aggregated.

[Colored toner]
The colored toner containing the colorant of the variable dye (A) shall contain the colorant of the variable dye (A) in place of the metal source discolorant in the MS toner containing the metal source discolorant described above. It can be produced in the same manner as described above using the colorant of the variable dye (A) instead of the metal source colorant.
The content ratio of the colorant in the toner particles is preferably 2 to 11 parts by mass, more preferably 4 to 9 parts by mass with respect to 100 parts by mass of the binder resin.

  As the colorant of the variable dye (A), the yellow colorant represented by the general formula (Y), the magenta colorant represented by the general formula (M), or the general formula (C) And the cyan colorant represented.

[Yellow colorant]
In the general formula (Y) representing a yellow colorant, R ¹¹ and R ¹² each represent a hydrogen atom or a monovalent organic group, and R ¹³ represents an alkyl group or an aryl group which may have a substituent. Z represents an atomic group necessary for forming a 5-membered or 6-membered aromatic ring with two carbon atoms.

  As the yellow colorant represented by the general formula (Y), for example, a compound represented by the following general formula (Ya) can be obtained from Chemical Reviews, Vol. 75, 241 (1975), and can be produced by performing a known coupling reaction with this and a compound represented by the following general formula (Yb).

Wherein, R ^11, R ^12, R ¹³ and Z, respectively, the same meanings as R ^11, R ^12, R ¹³ and Z in the general formula (Y).

  Specific examples of the yellow colorant represented by the general formula (Y) include compounds represented by the following formulas Y-1 to Y-32, but are not limited thereto.

[Magenta colorant]
In the general formula (M) representing a magenta colorant, R ²¹ represents a hydrogen atom, a halogen atom or a monovalent organic group, and R ²² represents an optionally substituted aromatic carbocyclic group or aromatic heterocycle. Represents a cyclic group, and R ²³ represents the above general formula (2) or (3). X represents a methine group or a nitrogen atom.

In the general formula (2), X ′ represents a carbon atom or a nitrogen atom, and Y represents an atomic group necessary for forming a nitrogen-containing aromatic heterocyclic ring. Further, in the general formula (3), W represents an atomic group necessary to form two aromatic carbocyclic or aromatic heterocyclic ring with the carbon atom, R ²⁴ represents an alkyl group.

  The magenta colorant represented by formula (M) can be synthesized according to a conventionally known method. For example, the azomethine dye in the general formula (M) can be synthesized according to the oxidative coupling method described in JP-A-63-113077, JP-A-3-275767, and JP-A-4-89287. it can.

  Specific examples of the magenta colorant represented by the general formula (M) include compounds represented by the following formulas M-1 to M-45, but are not limited thereto.

[Cyan colorant]
In the general formula (C) representing a cyan colorant, R ³¹ and R ³² each represent a substituted or unsubstituted aliphatic group, and R ³³ represents a monovalent organic group. n represents an integer of 0 to 4, and when n is 2 or more, the plurality of R ³³ may be the same or different. R ³⁴ , R ³⁵ and R ³⁶ all represent an alkyl group, but R ³⁴ , R ³⁵ and R ³⁶ may be the same or different. However, R ³⁵ and R ³⁶ is an alkyl group having 3 to 8 carbon atoms.

  The cyan colorant represented by the general formula (C) can be synthesized according to a conventionally known method. For example, it can be synthesized according to the oxidative coupling method described in JP-A-2000-2255171, JP-A-2001-334755, JP-A-2002-234266, and the like.

  Specific examples of the cyan colorant represented by the general formula (C) include compounds represented by the following formulas C-1 to C-36, but are not limited thereto.

[Black toner]
When black toner is used in combination with the image forming method of the present invention, general black electrostatic charge image developing toner can be used.

[Toner softening point]
The softening point of the MS toner, the colored toner of each primary color, and the black toner (hereinafter also simply referred to as “toner”) is preferably 80 to 150 ° C.

The softening point of the toner is measured by a flow tester shown below.
Specifically, first, in an environment of 20 ° C. and 50% RH, 1.1 g of toner was placed in a petri dish, leveled, allowed to stand for 12 hours or more, and then a molding machine “SSP-10A” (manufactured by Shimadzu Corporation). ) Is pressed for 30 seconds with a force of 3820 kg / cm ² to prepare a cylindrical molded sample having a diameter of 1 cm, and this molded sample is then subjected to flow tester “CFT-500D” in an environment of 24 ° C. and 50% RH. ”(Manufactured by Shimadzu Corporation) with a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./minute, from the hole of the cylindrical die (1 mm diameter × 1 mm) extruded from the time of preheating ends with 1cm piston, offset method temperature T _offset measured by setting the offset value 5mm at a melt temperature measurement method of temperature ramps is the softening point of the toner That.

[Toner glass transition point]
The glass transition point of the above toner is preferably 20 to 60 ° C.

The glass transition point of the toner is measured using “Diamond DSC” (manufactured by PerkinElmer).
As a measurement procedure, 3.0 mg of a sample (toner) is sealed in an aluminum pan and set in a holder. The reference used an empty aluminum pan. The measurement conditions were a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. Perform analysis based on the data in Heat, draw a baseline extension before the rise of the first endothermic peak, and a tangent line indicating the maximum slope between the rise of the first peak and the peak apex, The intersection point is shown as the glass transition point.

[Average toner particle size]
The average particle diameter of the toner is preferably 4 to 10 μm, and more preferably 6 to 9 μm, for example, on a volume basis median diameter. This particle size can be controlled by the concentration of the coagulant used, the amount of organic solvent added, the fusing time, and the composition of the polymer, for example, when the emulsion coagulation method described later is employed.
When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

The volume-based median diameter of the toner is measured and calculated using a measuring apparatus in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter). Is.
Specifically, 0.02 g of a sample (toner) was added to 20 mL of a surfactant solution (for example, a surfactant solution in which a neutral detergent containing a surfactant component was diluted 10 times with pure water for the purpose of dispersing toner particles. ), Followed by ultrasonic dispersion for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in the sample stand. Inject with a pipette until the displayed concentration of the measuring device is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle size is the volume-based median diameter.

[Average circularity of toner]
The average circularity of the toner is preferably 0.930 to 1.000, more preferably 0.950 to 0.995, from the viewpoint of improving transfer efficiency.

The average circularity of the toner is measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, the sample (toner) was blended with an aqueous solution containing a surfactant, dispersed by performing ultrasonic dispersion for 1 minute, and then subjected to measurement conditions HPF (by FPIA-2100) (manufactured by Sysmex). In the high magnification imaging mode, photographing is performed at an appropriate density of 3,000 to 10,000 HPF detections, and the circularity of each toner particle is calculated according to the following formula (T). Is calculated by dividing by the total number of toner particles.
Formula (T): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

  In the image forming method of the present invention, MS toner, colored toner such as yellow toner, magenta toner, and cyan toner, and further black toner are used together. Such MS toner, yellow toner, magenta toner, cyan toner are used together. The toner and the black toner are preferably designed so that their softening point, average particle diameter, average circularity, and the like are the same.

(External additive)
The toner particles can be used as toners as they are, but from the viewpoint of improving the charging performance, fluidity, or cleaning properties of the toner, the surface thereof includes a so-called post-treatment agent such as a fluidizing agent and a cleaning aid. An external additive may be added and used.
As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.
These inorganic fine particles are preferably subjected to a surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.
Various external additives may be used in combination.

  The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner particles.

(Developer)
The MS toner, the colored toner and the black toner can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, it is preferable to use ferrite particles. Further, as the carrier, a coat carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a binder type carrier in which magnetic fine powder is dispersed in a binder resin, or the like may be used.
The coating resin constituting the coat carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluorine resins. Moreover, it does not specifically limit as resin which comprises a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic-type resin, a polyester resin, a fluororesin, a phenol resin etc. can be used.
Preferred carriers include a coated carrier using a silicone resin, a copolymer resin (graft resin) of an organopolysiloxane and a vinyl monomer or a polyester resin as a coating resin from the viewpoint of spent resistance. Coat carrier coated with resin obtained by reacting isocyanate with copolymer resin (graft resin) of organopolysiloxane and vinyl monomer from the viewpoint of durability, environmental stability and spent resistance Are preferable.

  When toner is used as a two-component developer, the mixing amount of the toner with respect to the carrier is preferably 2 to 10% by mass.

The carrier preferably has an average particle diameter of 20 to 100 μm, more preferably 20 to 60 μm, in terms of volume-based median diameter.
In the present invention, the volume-based median diameter of the carrier is typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. It is.

According to the image forming method as described above, a light image portion that develops a visible color (LA) different from the primary color image portion can be formed by superimposing the color change toner image 5 on the primary color toner image 2. Therefore, it is possible to obtain color development in a very wide color gamut in the obtained visible image.
In particular, when a plurality of colors are used as the colorant of the variable dye (A), it is possible to obtain a color in a very wide color gamut by using a small amount of toner.

As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.
For example, the color toner image is not limited to a method in which the primary color toner image and the color change toner image are overlapped in an unfixed state and heat-fixed together, and the primary color toner image is once heat-fixed and then heat-fixed. A system may be employed in which a toner image made of MS toner is overlaid on a fixed image made of toner and heated and fixed again.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[MS toner production example 1]
(1) Preparation of Metal Source Discolorant Dispersion Solution An aqueous surfactant solution was prepared by stirring and dissolving 11.5 parts by mass of sodium n-dodecyl sulfate in 160 parts by mass of ion-exchanged water. To this surfactant aqueous solution, 19.4 parts by mass of the metal source discoloring agent represented by the formula (1-13) was gradually added, and then “Cleamix W Motion CLM-0.8” (M Technique Co., Ltd.). The metal source color changing agent dispersion liquid [1] in which the particles of the metal source color changing agent were dispersed was prepared.
With respect to the particle size of the metal source color changer particles in the metal source color change agent dispersion [1], the volume-based median size was measured and found to be 221 nm.
The volume-based median diameter is “MICROTRAC UPA-150” (manufactured by HONEYWELL), sample refractive index 1.59, sample specific gravity 1.05 (in terms of spherical particles), solvent refractive index 1.33, solvent viscosity. The measurement was performed by adjusting the zero point by introducing ion-exchanged water into the measurement cell under the measurement conditions of 0.797 (30 ° C.) and 1.002 (20 ° C.).

(2) Preparation of resin fine particle dispersion 7.08 g of an anionic surfactant (sodium dodecylbenzenesulfonate: SDS) was previously ion-exchanged into a separable flask equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introduction device. A surfactant solution dissolved in 2760 g of water was added, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. On the other hand, 72.0 g of a release agent represented by the following formula (W), 112.8 g of styrene, 41.0 g of n-butyl acrylate, and 10.7 g of methacrylic acid were heated to 80 ° C. and dissolved to obtain a monomer solution. Was prepared. Here, the two heated solutions were mixed and dispersed by a mechanical disperser having a circulation path to produce emulsified particles having a uniform dispersed particle size.
Formula (W): C {CH ₂ OCO (CH ₂ ) ₂₀ CH ₃ } ₄
Next, a resin fine particle was prepared by adding a solution obtained by dissolving 0.82 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water, and heating and stirring at 80 ° C. for 3 hours. Further, a solution prepared by dissolving 7.84 g of a polymerization initiator (KPS) in 240 g of ion-exchanged water was added, and after 15 minutes, styrene 376 g, n-butyl acrylate 137.2 g, and methacrylic acid 35.7 g were mixed at 80 ° C. A liquid obtained by adding 9.8 g of NOMP as a water-soluble chain transfer agent to the liquid (second monomer solution) was dropped over 120 minutes. After completion of dropping, the mixture was heated and stirred for 60 minutes and then cooled to 40 ° C. to prepare a dispersion of resin fine particles [1] (resin fine particle dispersion [1]).

(3) Preparation of MS toner 1250 g of resin fine particle dispersion [1], 2000 g of ion exchange water and 165 g of metal source discolorant fine particle dispersion [1] were attached with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device. The mixture was stirred in a liter four-necked flask and adjusted to 30 ° C., and then a 5 mol / L aqueous sodium hydroxide solution was added to the solution to adjust the pH to 10.0. Next, an aqueous solution obtained by dissolving 52.6 g of magnesium chloride hexahydrate in 72 g of ion-exchanged water was added with stirring at 30 ° C. over 10 minutes. Then, after standing for 3 minutes, the temperature increase was started and the temperature was increased to 90 ° C. over 6 minutes (temperature increase rate = 10 ° C./min). In this state, the particle diameter was measured with “Coulter Counter TA-III” (manufactured by Coulter Beckman). When the volume-based median diameter reached 6.5 μm, 115 g of sodium chloride was dissolved in 700 g of ion-exchanged water. The aqueous solution was added to stop particle growth, and the mixture was further heated and stirred at a liquid temperature of 90 ° C. ± 2 ° C. for 6 hours for fusion. Then, it cooled to 30 degreeC on the conditions of 6 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced toner particles are separated into solid and liquid, and washing with ion-exchanged water is repeated four times (the amount of ion-exchanged water is 15 liters), and then dried with hot air of 40 ° C. 1] was obtained.

(4) Addition of External Additive Hydrophobic silica (number average primary particle size = 12 nm, hydrophobization degree = 68) is then added to the MS toner particles [1] at a ratio of 1% by mass, and hydrophobicity is added. Titanium oxide (number average primary particle size = 20 nm, hydrophobization degree = 63) was added at a ratio of 1% by mass, mixed by “Henschel mixer” (Mitsui Miike Chemical Co., Ltd.), and then 45 μm Coarse particles were removed using an open sieve to prepare MS toner [1-13].

[MS toner production example 2]
In the production example 1 of MS toner, except that the metal source color changing agent represented by the formula (1-1) was used instead of the metal source color changing agent represented by the formula (1-13), MS toner [1-1] was prepared.

[MS toner production example 3]
In the production example 1 of MS toner, except that the metal source color changing agent represented by the formula (1-2) was used instead of the metal source color changing agent represented by the formula (1-13), MS toner [1-2] was prepared.

[Magenta Toner Production Example 1]
(1) Preparation of Variable Dye Dispersion Solution An aqueous surfactant solution was prepared by adding 7.0 parts by mass of sodium n-dodecyl sulfate to 160 parts by mass of ion-exchanged water and dissolving with stirring. 20 parts by mass of the variable dye represented by the formula (M-1) is gradually added to this surfactant aqueous solution, and then dispersed using “CLEARMIX W-Motion CLM-0.8 (M Technique Co., Ltd.)”. By performing the treatment, a variable dye fine particle dispersion [M1] was prepared.
The volume-based median diameter of the variable dye fine particles in this variable dye fine particle dispersion [M1] was measured and found to be 292 nm.
The volume-based median diameter is “MICROTRAC UPA-150” (manufactured by HONEYWELL), sample refractive index 1.59, sample specific gravity 1.05 (in terms of spherical particles), solvent refractive index 1.33, solvent viscosity. The measurement was performed by adjusting the zero point by introducing ion-exchanged water into the measurement cell under the measurement conditions of 0.797 (30 ° C.) and 1.002 (20 ° C.).

(2) Preparation of resin fine particle dispersion (a) First stage polymerization An anionic surfactant (sodium dodecyl sulfate: C ₁₀ H ₂₁ ( A surfactant aqueous solution in which 4 parts by mass of OCH ₂ CH ₂ ) ₂ SO ₃ Na) is dissolved in 3040 parts by mass of ion-exchanged water is added, and 10 parts by mass of potassium persulfate (KPS) is dissolved in 400 parts by mass of ion-exchanged water. After the polymerization initiator solution was added and the liquid temperature was raised to 75 ° C.,
-Styrene 532 mass parts-n-butyl acrylate 200 mass parts-Methacrylic acid 68 mass parts-n-octyl mercaptan 16.4 mass parts polymerizable monomer solution [a] was dripped over 1 hour. After completion of the dropwise addition, the resin fine particle dispersion [1H] in which the resin fine particles [1h] were dispersed was prepared by heating and stirring at 75 ° C. for 2 hours to perform a polymerization reaction (first stage polymerization). The formed resin fine particles [1h] had a weight average molecular weight of 16,500.

(B) Second stage polymerization In a flask equipped with a stirrer,
-Styrene 101.1 parts-n-butyl acrylate 62.2 parts-methacrylic acid 12.3 parts-n-octyl mercaptan 1.75 parts by weight are charged and mixed.
-Paraffin wax “HNP-57 (manufactured by Nippon Seiwa Co., Ltd.)” 93.8 parts by mass were charged, and the internal temperature was raised to 90 ° C. to dissolve this wax, thereby allowing the polymerizable unit containing paraffin wax to be dissolved. A monomer solution [b] was prepared.
On the other hand, an aqueous surfactant solution in which 3 parts by mass of an anionic surfactant (sodium dodecyl sulfate: C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ SO ₃ Na) was dissolved in 1560 parts by mass of ion-exchanged water had an internal temperature of 98. The resin fine particle dispersion [1H] (32.8 parts by mass) (in terms of solid content) is added to the aqueous surfactant solution, and the polymerizable monomer containing the paraffin wax is added. The monomer solution [b] was added. Thereafter, by performing a mixing and dispersion treatment for 8 hours using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path, oil droplet particle dispersion containing oil droplet particles having a dispersed particle diameter of 340 nm is performed. A liquid was prepared.
A polymerization initiator solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added to this oil droplet dispersion, and the mixture was heated and stirred at 98 ° C. for 12 hours to conduct a polymerization reaction (second-stage polymerization). ) To prepare a resin fine particle dispersion [1HM] in which resin fine particles [1hm] are dispersed. The formed resin fine particles [1 hm] had a weight average molecular weight of 23,000.

(C) Third stage polymerization A polymerization initiator solution in which 5.45 parts by mass of potassium persulfate was dissolved in 220 parts by mass of ion-exchanged water was added to the resin fine particle dispersion [1HM].
-Styrene 293.8 mass parts-n-butyl acrylate 154.1 mass parts-n-octyl mercaptan 7.08 mass parts polymerizable monomer solution [c] in 80 degreeC temperature conditions over 1 hour It was dripped. After completion of dropping, the mixture is heated and stirred for 2 hours to conduct a polymerization reaction (third-stage polymerization), and then cooled to 28 ° C. to produce a resin fine particle dispersion [2] in which resin fine particles [2] are dispersed. did. The formed resin fine particles [2] had a weight average molecular weight of 26,800.

(3) Preparation of toner particles In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, resin fine particle dispersion [2] 420.7 parts by mass (solid content conversion), ion exchanged water 500 parts by mass And 4.2 parts by mass of the variable dye fine particle dispersion [M1] (in terms of solid content) were added, the internal temperature was adjusted to 30 ° C. while stirring, and then a 5 mol / liter sodium hydroxide aqueous solution was added. The pH was adjusted to 10.
Next, an aqueous solution in which 2 parts by mass of magnesium chloride hexahydrate was dissolved in 1000 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After the addition, the mixture was allowed to stand for 3 minutes and then the temperature increase was started. The system was heated to 75 ° C. over 60 minutes. In this state, the average particle diameter of the aggregated particles was measured with “Coulter Multisizer 3 (manufactured by Beckman Coulter)”, and when the volume-based median diameter reached 6.5 μm, 8.2 parts by mass of sodium chloride was added. An aqueous solution dissolved in 50 parts by mass of ion-exchanged water was added to stop particle growth. Further, the temperature of the liquid was set to 80 ° C., and the mixture was heated and stirred for 4 hours to continue the fusion, thereby obtaining a toner particle dispersion liquid [M1] in which the toner particles [M1] were dispersed. With respect to this, the average circularity of the toner particles was measured using “FPIA2100 (manufactured by Sysmex Corporation)” and found to be 0.940.
Next, the toner particle dispersion [M1] was cooled to 30 ° C. under the condition of 8 ° C./min, filtered, and further washed with ion exchange water at 45 ° C. After completion of the washing treatment, the toner particles [M1] having a volume-based median diameter of 6.2 μm were produced by drying with hot air of 40 ° C.

(4) Addition of external additive Next, 0.6 parts by mass of hexamethylsilazane-treated silica (average primary particle size 12 nm) and n-octylsilane-treated titanium dioxide (average primary particles) were added to the toner particles [M1]. Add 0.8 parts by mass (diameter 24 nm), and use “Henschel Mixer” (Mitsui Miike Mining Co., Ltd.) and mix under conditions of a stirring blade peripheral speed of 35 m / sec, a processing temperature of 35 ° C., and a processing time of 15 minutes. Thus, magenta toner [M-1] was produced.

[Magenta toner production example 2]
In the same manner as in Magenta toner production example 1, except that the variable dye represented by formula (M-2) was used instead of the variable dye represented by formula (M-1), the magenta toner [M -2].

[Magenta toner production example 3]
In the same manner as in Magenta toner production example 1, except that the variable dye represented by formula (M-3) was used instead of the variable dye represented by formula (M-1), the magenta toner [M -3].

[Magenta Toner Production Example 4]
In the same manner as in Magenta toner production example 1, except that the variable dye represented by formula (M-4) was used instead of the variable dye represented by formula (M-1), the magenta toner [M -4].

[Magenta toner production example 5: for comparison]
In the same manner as in Magenta Toner Production Example 1, except that the pigment “CI Pigment Red 122” was used instead of the variable dye represented by Formula (M-1), the magenta toner [MP] Was made.

[Production Example 1 of Yellow Toner]
In the magenta toner production example 1, a yellow toner [Y is used in the same manner except that the variable dye represented by the formula (Y-1) is used instead of the variable dye represented by the formula (M-1). -1] was produced.

[Production Example 2 of Yellow Toner]
In the yellow toner production example 1, a yellow toner [Y is used in the same manner except that the variable dye represented by the formula (Y-2) is used instead of the variable dye represented by the formula (Y-1). -2].

[Production Example 3 of Yellow Toner]
In the yellow toner production example 1, a yellow toner [Y is used in the same manner except that the variable dye represented by the formula (Y-3) is used instead of the variable dye represented by the formula (Y-1). -3].

[Production Example 4 of Yellow Toner]
In the yellow toner production example 1, a yellow toner [Y is used in the same manner except that the variable dye represented by the formula (Y-4) is used instead of the variable dye represented by the formula (Y-1). -4].

[Yellow toner production example 2: for comparison]
In the same manner as in the production example 1 of yellow toner, except that the pigment “CI Pigment Yellow 74” was used instead of the variable dye represented by the formula (Y-1), the yellow toner [YP] Was made.

[Cyan toner production example 1]
In the same manner as in Magenta toner production example 1, except that the variable dye represented by formula (C-1) was used instead of the variable dye represented by formula (M-1), cyan toner [C -1] was produced.

[Cyan toner production example 2]
In the cyan toner production example 1, the cyan toner [C-2] was used in the same manner except that the variable dye represented by the formula (C-2) was used instead of the variable dye represented by the formula (C-1). -2].

[Cyan toner production example 3]
In the cyan toner production example 1, the cyan toner [C1] was used in the same manner except that the variable dye represented by the formula (C-3) was used instead of the variable dye represented by the formula (C-1). -3].

[Cyan toner production example 4]
In the cyan toner production example 1, the cyan toner [C] is used except that the variable dye represented by the formula (C-4) is used instead of the variable dye represented by the formula (C-1). -4].

[Cyan toner production example 2: for comparison]
Cyan toner [CP] was produced in the same manner as in Production Example 1 of Cyan Toner except that copper phthalocyanine was used instead of the variable dye represented by Formula (C-1).

[Developer Production Example 1]
MS toner [1-13], [1-1], [1-2], magenta toner [M-1] to [M-4], [MP], yellow toner [Y-1] to [Y-4] ], [YP], cyan toners [C-1] to [C-4], [CP], a ferrite carrier having a volume average particle diameter of 60 [mu] m coated with a silicone resin, and a concentration of MS toner [1] of 6 mass %, MS developer [1-13], [1-1], [1-2], magenta developer [M-1] to [M-4], [MP], yellow Developers [Y-1] to [Y-4] and [YP] and cyan developers [C-1] to [C-4] and [CP] were obtained.

[Examples 1 and 3-6, Comparative Examples 1 and 2]
MS developer [1-13], [1-1], [1-2], magenta developer [M-1] to [M-4], [MP], yellow developer [Y-1] to [Y-1] Y-4], [YP], cyan developers [C-1] to [C-4], [CP] are used in the combinations shown in Table 1, and a full-color high-speed multifunction device “bizhub PRO C6500” (Konica Minolta) A solid patch fixing image of yellow (Y), magenta (M), cyan (C), light yellow (LY), light magenta (LM), and light cyan (LC) was formed on the transfer paper by Business Technologies. Each toner adhesion amount was 1.0 mg / cm ² .

[Example 2]
Using a MS developer [1-13], a magenta developer [M-2], a yellow developer [Y-2], and a cyan developer [C-2], a full-color high-speed multifunction device “bizhub PRO C6500” (Konica A solid patch fixing image of yellow (Y), magenta (M), and cyan (C) was formed on transfer paper by Minolta Business Technologies. Next, an MS toner image is developed on a part of the solid patch fixed image of yellow (Y), magenta (M), and cyan (C), thereby obtaining light yellow (LY), light magenta (LM), and light cyan. A solid patch-fixed image of each of (LC) was formed. Each toner adhesion amount was 1.0 mg / cm ² .

[Evaluation of color gamut]
About each obtained solid patch fixing image, L ^* a ^* b ^* of a 2002 color patch was measured using the spectrophotometer "Gretag Macbeth Spectrolino" (made by Gretag Macbeth), and solid patch fixing in each Example and a comparative example was carried out. The color gamut volume ratio in the combination of images was calculated, and the color gamut volume ratio of Japan Color was expressed as 100%. The results are shown in Table 1.
In the present invention, the case where the color gamut volume ratio is 110% or more was evaluated as an acceptable level.

DESCRIPTION OF SYMBOLS 1 Visible image 2 Primary color toner image 5 Changeable toner image 8 Light image portion 9 Primary color image portion 10 Intermediate transfer portion 11S, 11Y, 11M, 11C, 11Bk Photoconductor 12 Cleaning means 13S, 13Y, 13M, 13C, 13Bk Primary Transfer roller 13A Secondary transfer roller 16 Intermediate transfer members 16a to 16d Support roller 20S MS toner image forming units 20Y, 20M, 20C Primary color toner image forming unit 20Bk Black toner image forming units 21S, 21Y, 21M, 21C, 21Bk Developing means 22S , 22Y, 22M, 22C, 22Bk Exposure means 23S, 23Y, 23M, 23C, 23Bk Charging means 25S, 25Y, 25M, 25C, 25Bk Cleaning means 26 Fixing device 27, 28 Heating and pressing roller 40 Paper discharge tray 41 Paper feed cassette 42 Paper feeding and conveying means 44a, 44 , 44c, 44d feed roller 46 registration rollers 47 discharge roller N nip P image support

Claims (4)

A primary color toner image formed by a toner containing a colorant of a variable dye (A) on an image support, and a visible color different from the variable dye (A) by reacting with the colorant of the variable dye (A) By superimposing and heat-fixing a color-change toner image formed by a toner containing a color-changing agent that develops (LA),
An image forming method for obtaining a visible image having an image portion that develops at least the visible color (LA) ,
The discoloring agent comprises a metal complex represented by the following general formula (1),
The colorant of the variable dye (A) is a yellow colorant represented by the following general formula (Y), a magenta colorant represented by the following general formula (M), or the following general formula (C). An image forming method , which is a cyan colorant .

[Wherein, M represents a divalent metal atom, R ¹ represents a hydrogen atom or a monovalent organic group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic ring. Group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or cyano group, R ³ represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group or A ring group is shown. ]

[Wherein R ¹¹ and R ¹² each represents a hydrogen atom or a monovalent organic group, R ¹³ represents an alkyl group or an aryl group which may have a substituent, and Z represents two An atomic group necessary for forming a 5-membered or 6-membered aromatic ring with a carbon atom is shown. ]

[Wherein R ²¹ represents a hydrogen atom, a halogen atom or a monovalent organic group, and R ²² represents an optionally substituted aromatic carbocyclic group or an optionally substituted aromatic heterocyclic group. , R ²³ represents the following general formula (2) or (3). X represents a methine group or a nitrogen atom. ]

[In general formula (2), X ′ represents a carbon atom or a nitrogen atom, and Y represents an atomic group necessary for forming a nitrogen-containing aromatic heterocyclic ring. Further, in the general formula (3), W represents an atomic group necessary to form two aromatic carbocyclic or aromatic heterocyclic ring with the carbon atom, R ²⁴ represents an alkyl group. ]

[Wherein R ³¹ and R ³² each represent a substituted or unsubstituted aliphatic group, and R ³³ represents a monovalent organic group. n represents an integer of 0 to 4, and when n is 2 or more, the plurality of R ³³ may be the same or different. R ³⁴ , R ³⁵ and R ³⁶ all represent an alkyl group, but R ³⁴ , R ³⁵ and R ³⁶ may be the same or different. However, R ³⁵ and R ³⁶ is an alkyl group having 3 to 8 carbon atoms. ]   On the image support,
  A yellow toner image formed by a toner containing a yellow colorant represented by the general formula (Y) according to claim 1;
  A magenta toner image formed by a toner containing a magenta colorant represented by the general formula (M) according to claim 1;
  A cyan toner image formed by a toner containing a cyan colorant represented by the general formula (C) according to claim 1;
  It reacts with any of the yellow colorant, the magenta colorant and the cyan colorant, respectively, and a visible color (light yellow) different from the yellow, a visible color (light magenta) different from the magenta, and the cyan, respectively. 2. The image forming method according to claim 1, wherein a toner image for color change formed by a toner containing a color changing agent that develops a different visible color (light cyan) is overlaid and heat-fixed.   Charging means for charging the photoreceptor;
  Exposure means for forming an electrostatic latent image by exposing a charged photoreceptor; and
  A plurality of image forming units having at least developing means for developing the electrostatic latent image with toner;
  An image forming apparatus comprising transfer means for transferring a developed toner image to an image support and fixing means for heating and fixing the toner image on the image support,
  The image forming unit reacts with a primary color image forming unit that develops with a toner containing a colorant of a variable dye (A) as a toner, and the colorant of the variable dye (A) as a toner. And a color changer image forming unit that develops with a toner containing a color changer that develops a different visible color (LA).
  The primary color toner image formed by the toner containing the colorant of the variable dye (A) on the image support and the visible color different from the variable dye (A) by reacting with the colorant of the variable dye (A). A visible image having an image portion that develops at least the visible color (LA) is obtained by superimposing and fixing the toner image for color change formed with a toner containing a color changing agent that develops the color (LA). And
  The discoloring agent comprises a metal complex represented by the following general formula (1),
  The colorant of the variable dye (A) is a yellow colorant represented by the following general formula (Y), a magenta colorant represented by the following general formula (M), or the following general formula (C). An image forming apparatus characterized by being a cyan colorant.

[Wherein M represents a divalent metal atom, R ¹ Represents a hydrogen atom or a monovalent organic group, R ² Represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or cyano group, and R ^Three Represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group. ]

[In the formula, R ¹¹ And R ¹² Each represents a hydrogen atom or a monovalent organic group, R ¹³ Represents an alkyl group or an aryl group which may have a substituent, and Z represents an atomic group necessary for forming a 5-membered or 6-membered aromatic ring together with 2 carbon atoms. ]

[In the formula, R ^{twenty one} Represents a hydrogen atom, a halogen atom or a monovalent organic group, R ^{twenty two} Represents an optionally substituted aromatic carbocyclic group or an optionally substituted aromatic heterocyclic group, R ^{twenty three} Represents the following general formula (2) or (3). X represents a methine group or a nitrogen atom. ]

[In general formula (2), X ′ represents a carbon atom or a nitrogen atom, and Y represents an atomic group necessary for forming a nitrogen-containing aromatic heterocyclic ring. In the general formula (3), W represents an atomic group necessary for forming an aromatic carbocycle or aromatic heterocycle with two carbon atoms, and R ^{twenty four} Represents an alkyl group. ]

[In the formula, R ³¹ And R ³² Each represents a substituted or unsubstituted aliphatic group, R ³³ Represents a monovalent organic group. n represents an integer of 0 to 4, and when n is 2 or more, a plurality of R ³³ May be the same or different. R ³⁴ , R ³⁵ And R ³⁶ Each represents an alkyl group, but R represents ³⁴ , R ³⁵ And R ³⁶ May be the same or different. However, R ³⁵ And R ³⁶ Is an alkyl group having 3 to 8 carbon atoms. ]   A plurality of primary color image forming units;
  The image forming unit of the primary color is a yellow image forming unit for developing with a toner containing a yellow colorant represented by the general formula (Y) according to claim 3 as a toner, and the toner according to claim 3 as a toner. A magenta image forming unit for developing with a toner containing a magenta colorant represented by the general formula (M), and a cyan colorant represented by the general formula (C) according to claim 3 as the toner. The image forming apparatus according to claim 3, further comprising a cyan image forming unit that develops the toner with the toner.