JP2010054799A - Full-color image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure lightness of a toner image formed by developing a latent image formed by short wavelength light with a color toner, and to provide a full-color image with good picture quality. <P>SOLUTION: A full-color image forming method is provided, in which a latent image formed by light at a wavelength of from 350 nm to 500 nm is developed with yellow, magenta and cyan toner. The lightness of a toner image formed with only the yellow toner is in a range from 80 to 90; the lightness of a toner image formed with only the magenta toner is in a range from 35 to 51; and the lightness of a toner image formed with only the cyan toner is in a range from 53 to 70. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic full-color image forming method, and more particularly, to develop an electrostatic latent image formed on an organic photoreceptor by short wavelength exposure using at least yellow, magenta, and cyan toners. It relates to a forming method.

  Electrophotographic image forming technology has found its way to producing documents and drawings in offices, etc., but in recent years, with the advancement of digital technology, it has been actively deployed in new markets such as the printing field. Is underway. Specifically, the use of short-wavelength exposure light (also called Blu-ray) having an oscillation wavelength of 350 nm to 500 nm, typified by short-wavelength laser light, improves writing accuracy and produces a much finer dot latent image than before. It has come to be formed on the photoreceptor. As a result, a fine electrostatic latent image is formed on the photoconductor, and an image having an image quality comparable to that of an image formed by an offset printing machine can be formed without the trouble of causing a plate. (For example, refer to Patent Document 1).

  However, charge transport materials for organic photoreceptors have the property of easily absorbing short-wavelength light, and deterioration proceeds due to repeated irradiation of such wavelength light, resulting in a decrease in sensitivity, an increase in residual potential, etc. Became easier to happen. As a result, the image quality of the printed image has a problem that the gradation changes and the image of the low density portion or the highlight portion is likely to be formed. Therefore, development of photoconductors that are difficult to deteriorate even after repeated exposure with short wavelength light with high energy density has been studied. For example, development of organic photoconductors using a highly durable triphenylamine compound as a charge transport material has been studied. (For example, see Patent Documents 2 to 4).

However, it is difficult to completely suppress degradation even with an organic photoreceptor using the triphenylamine compound disclosed in the above-mentioned patent document as a charge transport material. That was seen. Such variations in gradation and image quality hinder the formation of a predetermined full color image by superimposing a plurality of types of color toner images.
JP 2000-250239 A JP-A 63-278065 JP-A-7-261424 JP 2006-104183 A

  The present invention uses a short wavelength exposure light that is likely to accelerate deterioration of the organic photoreceptor, and even when repeated exposure over a long period of time, the image quality of the printed image does not deteriorate, and a full color image with good image quality is stable. It is an object of the present invention to provide an obtained image forming method. Specifically, even if short wavelength exposure with an oscillation wavelength of 350 nm to 500 nm is performed for a long time, the gradation does not change, and a stable full-color image with good image quality that is not in the low-density area or halftone image area is stable. The present invention provides an image forming method that can be formed as described above.

  The present inventor has found that the above problem is solved by the configuration described below.

The invention described in claim 1
“An electrostatic latent image is formed on the organic photoreceptor by exposing the organic photoreceptor using a light source having a wavelength of 350 nm to 500 nm, and the electrostatic latent image formed on the organic photoreceptor is at least Development using yellow toner, magenta toner, and cyan toner, transferring the toner image formed on the organic photoreceptor onto the transfer body, and then fixing the toner image to form a full-color image. A method,
When the toner image formed with only the yellow toner has the maximum saturation, the lightness L ^* _Y is in the range of 80 to 90,
When the toner image formed only with the magenta toner has the maximum saturation, the lightness L ^* _M is in the range of 35 to 51,
A full-color image forming method, wherein a lightness L ^* _C is in a range of 53 to 70 when the toner image formed only of the cyan toner has maximum saturation. ].

The invention described in claim 2
The full-color image forming method according to claim 1, wherein the magenta toner contains a compound represented by the following general formula (1).

[Wherein R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₇ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₁₅ and R ₁₆ each independently represent a hydrogen atom or carbon number. 1 or 2 alkyl groups are represented. M and n represent an integer of 1 or 2, and (X ⁻ ) represents a counter anion and represents a chlorine ion or a sulfonic acid compound ion. ]].

The invention according to claim 3
2. The full-color image forming method according to claim 1, wherein the magenta toner contains a compound represented by the following general formula (2).

[In the formula, each R ₂₁ independently represents a hydrogen atom or a substituent, R ₂₂ represents —NR ₂₄ R ₂₅ or —OR ₂₆ , and R ₂₃ represents a hydroxyl group, an alkoxy group, an aryloxy group, an amino group, an amide group, an alkylsulfonylamino group. Represents any group of an arylsulfonylamino group. A ₁₁ to A ₁₃ each independently represent a _{-CR 27} = or -N =.

X ₁₁ is an atomic group necessary for forming a 5- or 6-membered aromatic ring or heterocyclic ring, Z ₁ is a substituent necessary for forming a 5- or 6-membered heterocyclic ring containing at least one nitrogen atom And a condensed ring may be formed by the substituent. R _{24 to} R ₂₇ each independently represents a hydrogen atom or a substituent, L ₁₁ represents a linking group having 1 or 2 carbon atoms or a part of a ring structure, and is bonded to R ₂₃ to form a 5- or 6-membered ring structure. May be. p represents an integer of 0 to 3. ]].

The invention according to claim 4
The full-color image forming method according to any one of claims 1 to 3, wherein the cyan toner contains a compound represented by the following general formula (3).

[In the formula, each Z independently represents a hydroxy group, a chlorine group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following general formula (3-1). Show. A ^{1 to} A ⁴ represent a benzene ring. ]

[Wherein R ⁶¹ , R ⁶² , and R ⁶³ represent an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or an aryloxy group having 6 to 18 carbon atoms. Indicates a group. R ⁶¹ , R ⁶² and R ⁶³ may be the same group or different groups. ]].

The invention described in claim 5
The full-color image forming method according to any one of claims 1 to 4, wherein the organophotoreceptor contains a compound represented by the following general formula (4) as a charge transport material. .

[Wherein R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 5 carbon atoms or an alkoxy group, and R ₃ and R ₄ may have a substituent. N represents an integer of 0 to 2, m represents an integer of 0 to 3, and l and m represent an integer of 0 to 5. A, B, C and D represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, and A, B, C and D are not simultaneously a hydrogen atom. ]].

The invention described in claim 6
The full-color image forming method according to any one of claims 1 to 4, wherein the photoconductor contains a compound represented by the following general formula (5).

_{Wherein, R 5, R 6, R} 7 and _{R 8} represents an alkyl group or an alkoxy group having 1 to 5 carbon atoms. P represents an integer of 0 to 5, q represents an integer of 0 to 4, r represents an integer of 0 to 2, and s represents an integer of 0 to 3. A, B, C and D represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, and A, B, C and D are not simultaneously a hydrogen atom. ]].

  According to the present invention, in a full-color image forming method in which the surface of an organic photoreceptor is exposed using short-wavelength light having a transmission wavelength of 350 nm to 500 nm, a comfortable full-color image having a comfortable image quality can be stably obtained. It was. That is, even when repeated exposure with short-wavelength light that tends to degrade the charge transport material in the organophotoreceptor, the tonality does not change and full color with good image quality that does not appear in low-density areas or halftone image areas Images can be formed stably. Since there is no image blur in the halftone area, for example, when creating a photographic image with a lot of halftone areas, a high-quality full-color image that is comfortable to the eyes and rich in three-dimensionality and homogeneity can be obtained stably. I came to be able to.

  Therefore, even in a market called POD (Print On Demand) where there are many continuous print production opportunities, it is possible to stably provide full-color prints with a high-quality finish that are comfortable to the eyes even if short wavelength exposure is repeated for a long time. I was able to do it.

  In the present invention, an electrostatic latent image formed on an organic photoreceptor by exposure light having a wavelength of 350 nm to 500 nm is developed using at least yellow, magenta, and cyan color toners to form a full color toner image. Is.

  The present inventor specifies the brightness of each monochrome toner image of yellow toner, magenta toner, and cyan toner that develops an electrostatic latent image formed by irradiating exposure light having a wavelength of 350 nm to 500 nm on an organic photoreceptor. Thus, it has been found that good image quality can be stably obtained. As described above, the present invention can stably produce a full-color image with good image quality even under image forming conditions in which it is easy to place a load on the charge transport material in the organic photoreceptor by repeated exposure. became. Specifically, even when continuous printing is performed for a long time, the gradation does not change, and an image does not appear in a low density portion or a halftone image portion. In particular, since image defects such as image defects are not seen in the halftone area, for example, if a photographic image with a lot of halftone areas is produced, a full-color photographic image with a high-quality finish that is comfortable to the eyes rich in stereoscopic effect and homogeneity is obtained. It came to be obtained.

  In order to obtain a color image having a high-quality color that is comfortable to the eyes, the present inventor has made it possible to produce an image that is optimal for human visibility using toners of three colors of yellow, magenta, and cyan. I thought it was important. Then, by reconstructing the color design theory based on the Munsell color system model, we examined the toner image design that matches the human visual sensitivity.

  In the Munsell color system, the color tone can be illustrated by three attributes of hue, lightness, and saturation, which are called Munsell color solids. That is, the L axis representing the lightness is arranged at the center of the hue circle, the axis toward the bottom from the hue circle is blackened, and the axis toward the top is whitened. Further, the distance from the axis indicates the saturation, and the saturation increases as the distance from the axis increases. Usually, the Munsell color solid is not a perfect sphere, but forms a distorted sphere. This indicates that the human visual sensitivity cannot be detected equally for all hues.

  That is, there are four types of human photoreceptor cells: rod cells, blue cone cells, green cone cells, and red cone cells. Among them, the peak of the sensitivity curve of rod cells that sense brightness is 510 nm. Exists. In addition, blue cone cells (B cone) are sensitive to 400 to 500 nm, and the peak is about 430 nm. Green cone cells (G cones) are sensitive to the mid-wavelength range of 500-600 nm, and the peak is about 530 nm. Further, red cone cells (R cones) are sensitive to a long wavelength region of 550 to 650 nm, and the peak exists at about 560 nm. The peak of the red cone is not necessarily a red region, but rather a yellow-green to yellow region.

  The present inventor has sought to make it possible to set the brightness of the magenta toner, which controls the long wavelength region where the sensitivity of rod cells is low, to be higher than before. In the short wavelength range, the color tone is expressed by magenta and cyan, so the brightness of cyan toner was set to be higher than before. And, as we continue to study, we realize that simply increasing the brightness of these toner images will reduce the expressive power of the dark part of the image, and after further investigation, by combining the brightness when taking maximum saturation, It has been found that the effect is manifested. That is, the ideal distortion of the Munsell color solid, that is, the ideal degree of deformation from the sphere was found. In this way, by adjusting the brightness of the toner image, a full-color toner image with good image quality can be stably produced even under short-wavelength exposure image forming conditions that increase the burden on the organic photoreceptor due to repeated image formation. You can do it now.

  Hereinafter, the present invention will be specifically described.

In the present invention, a full color image is formed by developing an electrostatic latent image formed on an organic photoreceptor by short wavelength exposure using at least yellow toner, magenta toner, and cyan toner. The lightness L ^* _Y when the toner image formed with only yellow toner takes the maximum saturation is in the range of 80 to 90, preferably in the range of 85 to 90. Further, the lightness L ^* _M when the toner image formed only with magenta toner takes the maximum saturation is in the range of 35 to 51, preferably in the range of 40 to 49. Further, the lightness L ^* _C when the toner image formed only with cyan toner takes the maximum saturation is in the range of 53 to 70, preferably in the range of 57 to 67.

The lightness L ^* of each single color toner image is defined by the L ^* a ^* b ^* system color system. Here, the L ^* a ^* b ^* system color system is one of means used to express a color numerically. L ^* is a coordinate in the z-axis direction and represents lightness, and a ^* and b ^* are coordinates of the x-axis and the y-axis, respectively, and both represent hue and saturation. Note that lightness refers to the relative brightness of colors, hue refers to shades of red, yellow, green, blue, purple, etc., and saturation refers to the degree of color vividness. , Defined by the following equation (1).

That is, the saturation C ^* is a distance from the coordinate point (a, b) and the origin O, and is calculated from the following equation.

Formula (1): Saturation C ^* = [(a ^* ) ² + (b ^* ) ² ] ^1/2
In the L ^* a ^* b ^* color system, the color tone can be explained by the concept of hue angle. Here, the hue angle h is, for example, a half connecting a certain coordinate point (a, b) and the origin O on the x-axis-y-axis plane representing the relationship between hue and saturation when the lightness takes a certain value. The straight line is the angle formed by the straight line extending in the + direction (red direction) of the x axis in the counterclockwise direction from the + direction (red direction) of the x axis, and is calculated by the following equation (2).

Formula (1): Hue angle h = tan ⁻¹ (b ^* / a ^* )
In the x-axis-y-axis plane, the-(minus) direction of the x-axis indicated by a ^* is the green direction, and the + (plus) direction of the y-axis indicated by b ^* is the yellow direction. The-(minus) direction of the axis is the blue direction.

The maximum saturation referred to in the present invention is defined as follows. In general, when image formation is performed with toner containing a sufficient amount of colorant, the saturation of the toner image formed tends to increase as the toner adhesion amount increases on the transfer paper. However, when the toner adhesion amount exceeds a certain level, the increase in saturation changes to a stagnation and finally decreases. As described above, there is a case where the saturation of the formed toner image changes from rising to falling even though the toner adhesion amount is increasing, and the saturation at this time is defined as the maximum saturation. In addition, the amount of adhesion is measured by weighing an unfixed patch image of 20 mm × 50 mm together with the transfer paper, and then blow-off with an air gun until the transfer toner cannot be visually confirmed, and the remaining transfer paper is weighed again and transferred. Obtain the toner mass. Then, the toner adhesion amount per unit area is calculated by dividing the mass of the blown-off toner by the patch area. The transfer paper used for the adhesion amount measurement is gloss paper for electrophotography having a basis weight of 128 g / m ² , for example, “POD gloss coated paper” manufactured by Oji Paper Co., Ltd.

  On the other hand, when the toner adhesion amount and saturation maintain a proportional relationship as in the case of setting in the image forming apparatus, the toner adhesion amount on the transfer paper is maximized under the setting conditions of the image forming apparatus. The saturation of time is defined as the maximum saturation.

Specifically, L ^* a ^* b ^* for calculating the saturation C ^* and the hue angle h is measured using a spectrophotometer “Gretag Macbeth Spectrolino” (manufactured by Gretag Macbeth). As with the measurement of the reflection spectrum, a D65 light source is used as the light source, a φ4 mm reflection measurement aperture is used, the measurement wavelength range is 380 to 730 nm at 10 nm intervals, the viewing angle (observer) is 2 °, and white is used exclusively for reference adjustment. This is done under conditions using tiles.

The relationship between the toner adhesion amount and the saturation can be correlated by measuring the saturation of the toner image formed corresponding to each toner adhesion amount based on the gradation evaluation patch of “ECI2002 image data”. . In addition, the transfer paper used when measuring the saturation and the lightness is one having a basis weight of 128 g / m ² and a lightness of 93. For example, “POD gloss coated paper” manufactured by Oji Paper Co., Ltd. is there. The fixing condition of the toner image when measuring the saturation and the brightness is the standard fixing condition of the image forming apparatus used in the present invention. Further, the glossiness of the toner image when measuring the saturation and lightness is determined by measuring the glossiness of 75 ° using “Gloss Meter (manufactured by Murakami Color Research Laboratory)”, and at least the glossiness of 10 or more. It is measured.

The maximum saturation of a toner image formed only with yellow toner will be described. In the present invention, from the viewpoint of secondary colors formed using yellow toner, that is, green and red, the maximum chroma C ^* _Y of a toner image formed only with yellow toner is 85 to 115. preferable. Here, the maximum saturation of the yellow toner single color image is defined as follows.
(1) When the content of the toner colorant is set to be large, the saturation increases almost proportionally with the increase in the toner adhesion amount. However, if the content exceeds a certain level, the saturation increases even if the adhesion amount increases. It stops and it starts to decline. The saturation at which the saturation changes from rising to falling even though the toner adhesion amount is rising is defined as the maximum saturation in this case.
(2) When the toner adhesion amount is proportional to the saturation, the saturation of the toner image when the toner adhesion amount on the transfer paper that can be set by the image forming apparatus is maximized is defined as the maximum saturation in this case. .

The maximum saturation of yellow is measured at a hue angle of 75 degrees. At this time, the lightness of the yellow image is preferably set so that the lightness L ^* _Y is in the range of 80 to 90 when the yellow toner single color image has the maximum saturation from the viewpoint of green and red color development. ^* Set so that _Y is in the range of 85-90.

Next, the maximum saturation of a toner image formed only with magenta toner will be described. In the present invention, from the viewpoint of secondary colors formed using magenta toner, that is, blue and red, the maximum chroma C ^* _M of a toner image formed only with magenta toner is 70 to 100. preferable. Here, the definition of the maximum saturation of the magenta toner single color image is the same as that performed for the yellow toner single color image.

The maximum saturation of magenta is measured at a hue angle of 315 degrees. At this time, the lightness of the magenta image is preferably such that the lightness L ^* _M is in the range of 35 to 51 when the magenta toner single color image has the maximum saturation from the viewpoint of color development of blue, purple, and red. , L ^* _M is set in the range of 40-49.

Next, the maximum saturation of a toner image formed only with cyan toner will be described. In the present invention, from the viewpoint of secondary colors formed using cyan toner, that is, green and blue, the maximum chroma C ^* _C of a toner image formed only with cyan toner is 50 to 80. preferable. Here, the definition of the maximum saturation of the cyan toner monochromatic image is the same as that performed for the yellow toner monochromatic image.

Note that the maximum saturation of cyan is measured at a hue angle of 195 degrees. At this time, the lightness of the cyan image is preferably set so that the lightness L ^* _C is in the range of 53 to 70 when the cyan toner single-color image has the maximum saturation, from the viewpoint of yellow-green, green, and blue color development. Is set so that L ^* _C is in the range of 57-67.

  In the present invention, when the brightness when the toner image formed only with the yellow, magenta, and cyan toners takes the maximum saturation is within the above-described range, the charge transport material in the organic photoreceptor is subjected to a large burden. Even when wavelength exposure is performed for a long period of time, a full-color image with good image quality can be stably obtained. That is, even when repeated short wavelength exposures are performed over a long period of time, the gradation is not changed, and a full-color image having an image quality that is not in the low density part or the halftone image part can be stably produced. .

  As a result, according to the present invention, the image quality of a secondary color halftone toner image formed using a plurality of types of color toners is remarkably improved. As a result, high-quality images that are comfortable to the eyes can be created. In addition, since the amount of reflected light of the image is increased, the secondary color reproduction region can be expanded. Furthermore, as the amount of reflected light of the image increases, a rich contrast can be obtained not only for the black toner but also for the dark image formed by overlapping the yellow, magenta and cyan images.

Next, when a toner image formed only of yellow toner, magenta toner, and cyan toner has the maximum saturation, the lightness L ^* _Y , L ^* _M , and L ^* _C are within the above-described ranges. Will be described.

1. Yellow Toner First, a yellow toner that realizes the lightness L ^* _Y will be described.

In the present invention, as a yellow toner that develops an electrostatic latent image formed on an organic photoreceptor by exposure light having a wavelength of 350 nm to 500 nm, the lightness L when a toner image formed only of the yellow toner takes the maximum saturation. ^* _Y is in the range of 80-90.

  The yellow toner capable of realizing this is preferably one containing at least one yellow colorant shown in the following group X and group Y as a colorant, for example.

That is, for the colorant for yellow toner that achieves the lightness L ^* _Y , a dispersion liquid such as the following is mixed to adjust the reflection spectrum in the range of the following relational expressions (11) to (14). This work does not give the person skilled in the art much trial and error.

That is, by preparing a colorant particle dispersion for yellow toner and using a colorant whose reflection spectrum satisfies the following relational expressions (11) to (14), a yellow toner image having the lightness L ^* _Y in the above range is used. A yellow toner is formed.

Here, the reflection spectrum of the yellow monochromatic toner image is measured using a spectrophotometer “Gretag Macbeth Spectrolino” (manufactured by Gretag Macbeth). Measurement conditions were as follows: a D65 light source as a light source, a φ4 mm reflection measurement aperture, a measurement wavelength range of 380 to 730 nm with an interval of 10 nm, a viewing angle (observer) of 2 °, and a dedicated white tile for reference alignment. is there. The single color toner image for the reflection spectrum is formed using a transfer paper having a basis weight of 128 g / m ² and a lightness of 93. As an example, “POD gloss coated paper” manufactured by Oji Paper Co., Ltd. is used, and the glossiness of the image is determined by measuring 10 or more. The glossiness of the toner image is measured by using “Gloss Meter (manufactured by Murakami Color Engineering Laboratory)” with a glossiness of 75 degrees. Further, when forming a toner image, the fixing condition is the standard fixing condition of the image forming apparatus.

Relational expression (11) 2 ≦ A ₄₁₅ + A ₄₆₀ ≦ 24
[Wherein, A ₄₁₅ represents the reflectance (unit:%) at a wavelength of 415 nm, and A ₄₆₀ represents the reflectance (unit:%) at a wavelength of 460 nm. ]
Relational expression (12) 20 ≦ A ₅₁₀ −A ₄₉₀ ≦ 40
[Wherein, A ₅₁₀ represents the reflectance (unit:%) at a wavelength of 510 nm, and A ₄₉₀ represents the reflectance (unit:%) at a wavelength of 490 nm. ]
Relational expression (13) 2 ≦ A ₅₅₀ −A ₅₃₀ ≦ 16
Relational expression (14) 70 ≦ A ₅₅₀
[In the formula, A ₅₅₀ represents the reflectance (unit:%) at a wavelength of 550 nm, and A ₅₃₀ represents the reflectance (unit:%) at a wavelength of 530 nm. ]
The yellow colorants belonging to Group X and Group Y are as follows. That is,
[Group X]; I. Pigment yellow 3, C.I. I. Pigment yellow 35, C.I. I. Pigment yellow 65, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 98, C.I. I. Pigment Yellow 111
[Group Y]; I. Pigment yellow 9, C.I. I. Pigment yellow 36, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 181, C.I. I. Pigment Yellow 153
Particularly preferred is a yellow toner in which the mass ratio of the yellow colorant selected from the group X and the yellow colorant selected from the group Y is 65:35 to 95: 5.

2. Next, a magenta toner that realizes the lightness L ^* _M will be described.

In the present invention, as a magenta toner for developing an electrostatic latent image formed on an organic photoreceptor by exposure light having a wavelength of 350 nm to 500 nm, the lightness L when a toner image formed only with magenta toner takes the maximum saturation. ^{* The} thing whose _M exists in the range of 31-51 is used.

  As a magenta toner capable of realizing this, for example, there are magenta toners containing the following pigments, dyes, and complex compounds as colorants, and 1 to 30% of general-purpose pigments are included in the colorants shown below. A magenta colorant having a relatively strong bluish color is used.

That is, for the colorant for magenta toner that achieves the lightness L ^* _M , a dispersion such as the following is mixed to adjust the reflection spectrum in the range of the following relational expressions (21) to (24). This work does not give the person skilled in the art much trial and error.

That is, by preparing a colorant particle dispersion for magenta toner and using a colorant whose reflection spectrum satisfies the following relational expressions (21) to (24), a magenta toner image having the lightness L ^* _M in the above range. A magenta toner for forming the toner is realized.

Relational expression (21) 30 ≦ B ₄₅₀ −B ₅₂₀ ≦ 85
[In the formula, B ₄₅₀ represents the reflectance (unit:%) at a wavelength of 450 nm, and B ₅₂₀ represents the reflectance (unit:%) at a wavelength of 520 nm. ]
Relational expression (22) 1 ≦ B ₅₃₀ + B ₅₇₀ ≦ 25
[Wherein, B ₅₃₀ represents the reflectance (unit:%) at a wavelength of 530 nm, and B ₅₇₀ represents the reflectance (unit:%) at a wavelength of 570 nm. ]
Relational expression (23) 2 ≦ B ₆₇₀ −B ₆₀₀ ≦ 50
Relational expression (24) 80 ≦ B ₆₇₀
[In the formula, B ₆₇₀ represents the reflectance (unit:%) at a wavelength of 670 nm, and B ₆₀₀ represents the reflectance (unit:%) at a wavelength of 600 nm. ]
The measurement of the reflection spectrum of the magenta toner image is performed under the same conditions as the measurement of the reflection spectrum of the yellow toner image described above.

Specific examples of the pigment include the following. That is,
C. I. Pigment Red 2, 3, 6, 7, 15, 15, 16, 48: 1, 48: 3, 53: 1, 57: 1, 122, 123, 123, 139 144, 149, 166, 177, 178, 208, 208, 209, 222, etc.

Specific examples of the dye include the following. That is,
C. I. Solvent Red 3, 14, 17, 18, 22, 23, 49, 51, 53, 87, 127, 128, 131, 145, 146, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 176, 179, etc.

  As a preferred embodiment of the invention described in claim 1, the present inventor is a magenta toner containing magenta toner containing a compound represented by the following general formula (1) described in claim 2 as a preferred embodiment. I found out that

In the general formula (1), R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₇ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₁₅ and R ₁₆ are each independently hydrogen. An atom or an alkyl group having 1 or 2 carbon atoms is represented. M and n represent an integer of 1 or 2, and (X ⁻ ) represents a counter anion and represents a chlorine ion or a sulfonic acid compound ion.

  Specific examples of the compound represented by the general formula (1) include those shown below.

  In addition, as a preferred embodiment of the invention described in claim 1, the present inventor also includes a magenta toner containing a compound represented by the following general formula (2) described in claim 3 as a magenta toner. It was found that it is one of.

In the general formula (2), R ₂₁ is independently a hydrogen atom or a substituent, R ₂₂ is —NR ₂₄ R ₂₅ or —OR ₂₆ , and R ₂₃ is a hydroxyl group, an alkoxy group, an aryloxy group, an amino group, an amide group. Represents an alkylsulfonylamino group or an arylsulfonylamino group. A ₁₁ to A ₁₃ each independently represent a _{-CR 27} = or -N =.

X ₁₁ is an atomic group necessary for forming a 5- or 6-membered aromatic ring or heterocyclic ring, Z ₁ is a substituent necessary for forming a 5- or 6-membered heterocyclic ring containing at least one nitrogen atom And a condensed ring may be formed by the substituent. R _{24 to} R ₂₇ each independently represents a hydrogen atom or a substituent, L ₁₁ represents a linking group having 1 or 2 carbon atoms or a part of a ring structure, and is bonded to R ₂₃ to form a 5- or 6-membered ring structure. May be. p represents an integer of 0 to 3.

  Specific examples of the compound represented by the general formula (2) include those shown below.

  The compound represented by the general formula (2) acts as a colorant in the form of a complex compound as shown in complex compounds 1 and 2 below.

  Among the magenta colorants described above, mixtures of complex compounds 1 and 2 and compounds (1) -25 and (1) -26 are preferably used.

3. Cyan Toner Next, a cyan toner that realizes the lightness L ^* _C will be described.

In the present invention, as a cyan toner for developing an electrostatic latent image formed on an organic photoconductor by exposure light having a wavelength of 350 nm to 500 nm, the lightness L when a toner image formed only of the cyan toner takes the maximum saturation. ^* _C exists in the range of 53-70.

  As a preferable mode for realizing the invention of the first aspect, a cyan toner containing a silicon phthalocyanine compound represented by the following general formula (3) can be cited.

As the colorant for cyan toner that achieves the lightness L ^* _C , for example, a dispersion of a silicon phthalocyanine compound represented by the general formula (3) is reflected in the range of the following relational expressions (31) to (34). This operation does not give the person skilled in the art much trial and error.

That is, by preparing a colorant particle dispersion for cyan toner and using a colorant whose reflection spectrum satisfies the following relational expressions (31) to (34), a cyan toner image having a lightness L ^* _C in the above range. A cyan toner capable of forming a toner is realized.

Relational expression (31) 4 ≦ | C ₄₈₀ −C ₄₅₀ | ≦ 16
[Wherein, C ₄₈₀ represents the reflectance (unit:%) at a wavelength of 480 nm, and C ₄₅₀ represents the reflectance (unit:%) at a wavelength of 450 nm. ]
Relational expression (32) 15 ≦ C ₅₅₀ −C ₅₇₀ ≦ 35
Relational expression (33) 20 ≦ C ₅₇₀ ≦ 50
[Wherein, C ₅₅₀ represents the reflectance (unit:%) at a wavelength of 550 nm, and C ₅₇₀ represents the reflectance (unit:%) at a wavelength of 570 nm. ]
Relational expression (34) 0 ≦ C ₆₂₀ + C ₆₅₀ ≦ 30
[Wherein, C ₆₂₀ represents the reflectance (unit:%) at a wavelength of 620 nm, and C ₆₅₀ represents the reflectance (unit:%) at a wavelength of 650 nm. ]
The measurement of the reflection spectrum of the cyan toner image is performed under the same conditions as the measurement of the reflection spectrum of the yellow toner image described above.

As described above, some cyan toners that achieve the lightness L ^* _C contain a silicon phthalocyanine compound represented by the following general formula (3) as a colorant. In the silicon phthalocyanine compound represented by the general formula (3), a silicon atom (Si) is used as a metal atom (hereinafter also referred to as a central metal atom) located at the center of the phthalocyanine ring.

  Z in the general formula (3) is each independently represented by a hydroxy group, chlorine, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or the following general formula (3-1). It shows a compound.

R ⁶¹ , R ⁶² , and R ^{63 in the} general formula (3-1) are each an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a carbon number 6 to 18 aryloxy groups are shown. Here, R ⁶¹ , R ⁶² , and R ⁶³ may be the same group or different groups. These groups preferably have 1 to 10 carbon atoms, more preferably 2 to 8 carbon atoms.

In the general formula (3), A ¹ , A ² , A ³ and A ⁴ each independently represent a benzene ring.

  The cyan toner preferably used in the present invention contains a phthalocyanine compound having an axial ligand called a tetraazaporphine compound represented by the above general formula (3) in which a silicon atom is used as a central metal atom as a colorant. To do. Here, the axial ligand is represented by Z in the general formula (3).

  A toner containing the compound represented by the general formula (3) can exhibit better color reproducibility than a toner containing a phthalocyanine compound having no axial ligand. This is presumed to be because the compound represented by the general formula (3) has a more complicated structure than the phthalocyanine compound having no axial ligand, and the compound is less likely to aggregate and crystallize. As a result, it is considered that the color reproducibility is improved by maintaining the uniform dispersion of the colorant in the toner particles and the fixed image.

  Further, the phthalocyanine compound represented by the general formula (3) is incorporated into the toner particles in a uniformly dispersed state in the toner manufacturing process because of the structure that is difficult to aggregate and crystallize. This is thought to contribute to the expansion of the reproduction range.

  That is, in the full-color image forming method according to the present invention, the color tone reproduction region using the cyan toner is expanded by using the cyan toner containing the compound represented by the general formula (3). In particular, the reproduction of the blue color tone formed by the magenta toner and the cyan toner, which has been difficult to reproduce in the prior art, can be stably performed by the magenta toner and the cyan toner described above. As a result, the reproducibility of a hue region called blue violet, which has been considered to be particularly difficult in reproducing the color tone of a display display image, can be greatly improved.

Z constituting the compound represented by the general formula (3) is preferably a group represented by the general formula (3-1) among the groups described above. R ⁶¹ , R ⁶² and R ⁶³ in the group represented by the general formula (3-1) are preferably an alkyl group having 1 to 6 carbon atoms, an aryl group or an alkoxy group, particularly an n-propyl group, Isopropyl group, n-butyl group, isobutyl group and t-butyl group are preferred. R ⁶¹ , R ⁶² and R ⁶³ may be the same group or different groups.

  The cyan toner preferably used in the present invention can be used alone or in combination of two or more of the phthalocyanine compounds. The content of the phthalocyanine compound in the toner is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner. In particular, since the above compound is expected to have high molecular light absorbency, it is expected to have the possibility of exhibiting the effects of the present invention even if the addition amount is small.

  Specific examples of the tetraazaporphine compound (phthalocyanine compound having an axial ligand) represented by the general formula (3) are shown in Table 1, and are represented by the general formula (3) usable for the toner according to the present invention. The compounds are not limited to those shown in Table 1.

  Examples of the cyan toner preferably used in the full-color image forming method according to the present invention include those containing the above-mentioned phthalocyanine as a colorant, but a cyan toner using the following known cyan colorant in combination with the above phthalocyanine is also preferable. Used. For example, in addition to the above phthalocyanine, C.I. I. And cyan toner using a known cyan colorant such as CI Pigment Blue 15.

  In the cyan toner used in the present invention, a compound having a structure represented by the following general formula (II) can be used in combination with the aforementioned silicon phthalocyanine compound.

R ₂ constituting the above structural formula represents a hydrogen atom or an organic group. Specific examples of the compound represented by the general formula (II) include the following.

  Next, the structure of the yellow, magenta, and cyan toners used in the full color image forming method according to the present invention will be described.

  The yellow toner, magenta toner, and cyan toner used in the present invention preferably have a volume reference median diameter (D50v) of 3 μm or more and 8 μm or less. By setting the volume reference median diameter in the above range, for example, it is possible to faithfully reproduce a very minute dot image at a level of 1200 dpi (dpi; number of dots per inch (2.54 cm)).

  By setting the volume reference median diameter of the yellow toner, magenta toner, and cyan toner used in the present invention within the above-described range, it is possible to form a fine toner image required for producing a photographic image, a fine line image, and the like. In this way, a fine dot image produced by digital image formation is faithfully reproduced, so a high-definition image equivalent to or higher than the printed image can be obtained, so it may be superior to the printed image without taking the trouble of making a plate. It is possible to provide a high-quality full-color print that is not inferior.

  Further, when the particle diameter of the color toner is in the above range, a change in color tone is suppressed regardless of the amount of toner adhesion, and excellent color reproducibility can be obtained. On the other hand, when the particle size of the color toner is less than 3.0 μm in terms of volume-based median diameter, light scattering is likely to occur, and a halftone image formed with a small amount of toner attached and a toner attached with a large amount of toner are formed. There is a risk that the color tone will differ from the solid image. Specifically, a halftone image formed only with color toners may have a bluish hue.

  In the case where the color toner particles are formed by a polymerization method, the particle size of the toner is controlled by the concentration and addition amount of the flocculant, the aggregation time, and further the composition of the polymer itself in the color toner production method. be able to.

  The volume-based median diameter (D50v diameter) of the toner can be measured and calculated using an apparatus in which a computer system for data processing is connected to “Multisizer 3 (manufactured by Beckman Coulter)”.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing “ISOTONII (manufactured by Beckman Coulter)” in the sample stand with a pipette until the measured concentration reaches 5 to 10%, and the measured particle count is set to 25,000. And measure. In addition, the aperture diameter of the multisizer 3 is 50 μm, and the particle diameter of 50% is set as the volume-based median diameter by integrating from the larger particle volume.

  Further, the yellow toner, magenta toner, and cyan toner used in the present invention preferably have a coefficient of variation (CV value) in the volume-based particle size distribution of 2% to 21%, preferably 5% to 15%. More preferably.

  The coefficient of variation (CV value) in the volume-based particle size distribution represents the degree of dispersion in the particle size distribution of the toner particles on the volume basis, and is defined by the following equation.

CV value (%) = (standard deviation in number particle size distribution) / (median diameter (D50v) in number particle size distribution) × 100
A smaller CV value indicates a sharper particle size distribution, which means that the toner particles have the same size. In other words, since toners with uniform sizes can be obtained, it is possible to reproduce a fine dot image and fine lines required for digital image formation with higher accuracy. Further, when printing photographic images, it is possible to create high-quality photographic images at the image level or higher made with printing ink by using small-diameter toners of uniform sizes.

  Further, with respect to individual color toner particles constituting the color toner used in the present invention, an average value of circularity (also referred to as “average circularity”) represented by the following formula is 0.930 from the viewpoint of improving transfer efficiency. It is preferably ˜1.000, more preferably 0.950 to 0.995.

Formula: Average circularity = peripheral length of circle determined from equivalent circle diameter / perimeter length of projected particle image The toner softening point temperature (Tsp) is preferably 70 ° C. or higher and 110 ° C. or lower, preferably 70 ° C. or higher. What becomes 100 degrees C or less is more preferable. The colorant used in the toner has a stable property in which the spectrum does not change even under the influence of heat, but the effect of heat applied to the toner during fixing by setting the softening point in the above range Can be further reduced. Therefore, since it becomes possible to form an image without imposing a burden on the colorant, it is expected to express a wider and more stable color reproducibility.

  In addition, by setting the softening point temperatures of yellow, magenta, and cyan toners within the above range, yellow, magenta, and cyan toners can be appropriately melted in the fixing process, and a secondary color image having high color reproducibility can be obtained. Can be formed.

  Here, “appropriate melting state of yellow, magenta, and cyan toner” means that when a color image is formed by superimposing toner images of other colors on each toner image formed of yellow, magenta, and cyan toner. A state in which the yellow, magenta, and cyan colorants contained in the toner image formed with the yellow, magenta, and cyan toners and the colorants constituting the other colors are both uniformly dispersed and colored. Specifically, for example, when a yellow toner image and a magenta toner image are overlaid, the interface between the binder resin layers disappears while being a color image fixed in a color superimposed state on the recording material. Thus, a state in which the yellow colorant and the magenta colorant are uniformly dispersed is realized. At this time, the magenta colorant and the yellow colorant are not exuded in an area outside the color image area.

  Further, by setting the softening point of the toner within the above range, the toner image can be fixed at a temperature lower than that of the prior art, and an environment-friendly image formation with reduced power consumption can be performed.

The softening point of the toner can be controlled by, for example, the following methods alone or in combination. That is,
(1) The type and composition ratio of monomers used for resin formation are adjusted.
(2) The molecular weight of the resin is adjusted according to the type and amount of chain transfer agent.
(3) Adjust the type and amount of wax.

The softening point temperature of the toner is measured as follows. First, in an environment of 20 ° C. and 50% RH, 1.1 g of color toner is put in a petri dish and flattened, and left for 12 hours or more, and then a molding machine “SSP-10A (manufactured by Shimadzu Corporation)”. Is pressed with a force of 3820 kg / cm ² for 30 seconds to produce a cylindrical molded sample having a diameter of 1 cm.

  Next, this molded sample was subjected to a load of 196 N (20 kgf), a starting temperature of 60 ° C., and a preheating time of 300 seconds using a flow tester “CFT-500D (manufactured by Shimadzu Corporation)” in an environment of 24 ° C. and 50% RH. Extruding from a cylindrical die hole (1 mm diameter x 1 mm) using a piston with a diameter of 1 cm from the end of preheating under the condition of a heating rate of 6 ° C / min, and an offset value of 5 mm by the melting temperature measurement method of the heating method The offset method temperature Toffset measured with the setting is set as the softening point temperature of the color toner.

  Next, a method for producing yellow toner, magenta toner, and cyan toner used in the present invention will be described.

  The toner used in the present invention is composed of particles (hereinafter also referred to as colored particles) containing at least a resin and a colorant. The colored particles constituting the toner used in the present invention are not particularly limited, and can be produced by a conventional toner production method. That is, a toner manufacturing method by a so-called pulverization method in which a toner is prepared through kneading, pulverization, and classification steps, or a so-called polymerized toner in which a polymerizable monomer is polymerized and at the same time particle formation is performed while controlling the shape and size. It can be produced by applying a production method (for example, an emulsion polymerization method, a suspension polymerization method, a polyester elongation method, etc.).

  Next, the resin, wax, etc. constituting the yellow toner, magenta toner, and cyan toner used in the present invention will be described with specific examples.

  First, the resin that can be used for the toner is not particularly limited, but a polymer formed by polymerizing a polymerizable monomer called a vinyl monomer described below is representative. Is something. The polymer constituting the resin is composed of a polymer obtained by polymerizing at least one polymerizable monomer, and is composed of these vinyl monomers singly or in combination. It is.

Specific examples of vinyl polymerizable monomers are shown below.
(1) Styrene or styrene derivatives Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, etc. (2) Methacrylate derivatives Methyl methacrylate, methacryl Ethyl acetate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethyl methacrylate (3) Acrylic acid ester derivatives Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. (4) olefins Ethylene, propylene, isobutylene, etc. (5) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (6) Vinyl ether (7) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc. (8) N-vinyl compounds N-vinyl carbazole, N-vinyl indole (9) Others Vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, etc. As the polymerizable monomer, those having an ionic dissociation group shown below can be used. In particular, the colorant of the present invention has weak alkalinity as described above, and the one having an ionic dissociation group such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group in the side chain of the monomer is used. Further, the dispersibility in the resin can be further improved, which is preferable. Specifically, there are the following.

  First, those having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, and the like. Examples of those having a sulfonic acid group include styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, and examples of those having a phosphoric acid group include acid phosphooxyethyl methacrylate.

  Moreover, it is also possible to produce a resin having a crosslinked structure by using the following polyfunctional vinyls. Specific examples of polyfunctional vinyls are shown below.

Divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. Next, the present invention As the wax that can be used in the toner, there are known waxes as shown below.
(1) Polyolefin wax Polyethylene wax, polypropylene wax, etc. (2) Long chain hydrocarbon wax, paraffin wax, sazol wax, etc. (3) Dialkyl ketone wax, distearyl ketone, etc. (4) Ester wax Carnauba wax, Montan Wax, trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, 1,18-octadecanediol di Stearate, trimellitic trimellitic acid, distearyl maleate, etc. (5) Amide wax Ethylenediamine dibehenyl amide, trimellitic acid triste The melting point of Riruamido such as wax is usually from 40 to 125 ° C., preferably from 50 to 120 ° C., more preferably from 70 to 90 ° C.. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the wax content in the toner is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass.

  Next, the yellow toner, magenta toner, and cyan toner used in the present invention include inorganic fine particles and organic fine particles having a number average primary particle size of 4 to 800 nm as external additives (= external additives) in the production process. It can be added to make a toner.

  By adding the external additive, the fluidity and chargeability of the toner are improved, and the cleaning property is improved. The type of the external additive is not particularly limited, and examples thereof include the following inorganic fine particles, organic fine particles, and lubricants.

  As the inorganic fine particles, conventionally known fine particles can be used. For example, silica, titania, alumina, strontium titanate fine particles and the like are preferable. Moreover, what hydrophobized these inorganic fine particles as needed can also be used.

  Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150 manufactured by Hoechst, H -200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5, etc. manufactured by Cabot Corporation.

  As the titania fine particles, for example, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used.

  Further, a lubricant can be used to further improve the cleaning property and transfer property, and examples thereof include the following higher fatty acid metal salts. That is, salts of zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, salts of manganese, iron, copper, magnesium, etc., zinc palmitate, salts of copper, magnesium, calcium, etc., linoleic acid There are salts of zinc, calcium and the like, and zinc and calcium of ricinoleic acid.

  The addition amount of these external additives and lubricants is preferably 0.1 to 10.0% by mass with respect to the whole toner. In addition, these external additives and lubricants can be added using various known mixing devices such as a Turbula mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  Next, the organic photoreceptor used in the present invention will be described. The organic photoreceptor used in the present invention preferably uses a compound having a structure represented by the following general formula (4) or (5) as a charge transport material. That is,

R ₁ , R ₂ , R ₃ and R _{4 in} the general formula (4), and R ₅ , R ₆ , R ₇ and R ₈ in the general formula (5) are an alkyl group or an alkoxy group having 1 to 5 carbon atoms. R ₃ and R ₄ may have a substituent. Moreover, R <_9> , R < ₁₀ > in General formula (5) represents an alkyl group.

  In general formula (4), n is an integer of 0 to 2, m is an integer of 0 to 3, l and m are integers of 0 to 5, and p in general formula (5) is 0 to 5. Integer, q is an integer of 0-4, r is an integer of 0-2, s represents an integer of 0-3. Furthermore, A, B, C and D in both formulas represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, and A, B, C and D do not simultaneously become a hydrogen atom. Is.

Specific examples of the alkyl group having 1 to 5 carbon atoms in R _{1 to} R ₄ in the general formula (4) and R _{5 to} R ₈ in the general formula (5) include a methyl group, an ethyl group, and an n-propyl group. I-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl group, i-pentyl group and the like. Examples of the substituted alkyl group that can be used for R ₃ and R ₄ include a phenyl-substituted alkyl group. Specific examples of the alkoxy group having 1 to 5 carbon atoms in R _{1 to} R ₄ and R _{5 to} R ₈ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

Specific examples of the alkyl group in R ₉ and R ₁₀ in the general formula (5) include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group, and R ₉ and R ₁₀ are bonded to each other. Specific examples of the ring structure formed include a cyclohexyl group and a cyclopentyl group. Furthermore, specific examples of the aryl group in R ₉ and R ₁₀ include, for example, a phenyl group.

  A, B, C and D in both general formulas represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, alkoxy group and aryl group may have a substituent, Examples of the substituent include an alkyl group and an alkoxy group. In addition, as for the compound represented by General formula (4), (5), the thing in which A, B, C, and D in a formula do not become a hydrogen atom simultaneously is preferable.

  Specific examples of the alkyl group in A, B, C, and D include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group and the like having 1 to 4 carbon atoms. An alkyl group is mentioned. Examples of the alkyl group having a substituent include an alkoxyalkyl group, a benzyl group, and a phenethyl group. Specific examples of the alkoxy group in A, B, C and D include, for example, a methoxy group, an ethoxy group, and a propoxy group. Specific examples of the aryl group include, for example, a phenyl group. The compounds represented by the general formulas (5) and (6) are preferably those in which any of A, B, C and D is a methyl group.

  Specific examples of the compounds represented by general formula (4) and general formula (5) are shown below.

  The compound represented by the general formula (4) is synthesized by a known method such as an Ullmann reaction in which diphenylamine and an aryl halide are reacted in the presence of a copper and alkali catalyst, or a Suzuki coupling method using a palladium catalyst. Can do. Moreover, the compound represented by General formula (5) is compoundable by a well-known method, such as making the triphenylamine compound which has a biphenyl group react with various ketone compounds under an acid catalyst, for example.

  Next, the structure of the organic photoreceptor that can be used in the present invention will be described.

  The organic photoreceptor that can be used in the present invention is a photoreceptor having a configuration in which at least one of the charge generation function and the charge transport function of the photoreceptor is expressed by an organic compound. The organic photoreceptor usable in the present invention preferably contains the compound represented by the general formula (4) or (5) as a charge transport material, and the charge generation material exhibits a charge generation function. Any known organic compound can be used.

The organophotoreceptor that can be used in the present invention can have the structure shown below.
(1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support. (2) A charge generation layer, a first charge transport layer and a second charge as a photosensitive layer on a conductive support. Structure in which transport layers are sequentially laminated (3) Structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support (4) Charge as a photosensitive layer on a conductive support A structure in which a transport layer and a charge generation layer are sequentially laminated. (5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoconductor having the above-described structures (1) to (4).

  Further, an intermediate layer called an undercoat layer can be formed between the conductive support of the organic photoreceptor having the structure (1) to (5) and the photosensitive layer.

  The conductive support, intermediate layer, and photosensitive layer (charge generation layer, charge transport layer) constituting the organic photoreceptor will be described.

(1) Conductive support The conductive support is made of a metal drum such as aluminum or nickel, a plastic drum on which aluminum, tin oxide, indium oxide, or the like is vapor-deposited, or a paper or plastic drum coated with a conductive material. It has a cylindrical or sheet-like form. Among these, the cylindrical conductive support has a structure capable of forming an image endlessly on the photosensitive member by rotating the photosensitive member, and is also preferable for designing an image forming apparatus compactly.

(2) Intermediate layer The intermediate layer is provided between the conductive support and the photosensitive layer, and by incorporating N-type semiconductor particles such as titanium oxide and zinc oxide in the binder resin, the conductive support and the photosensitive layer are provided. Therefore, it is possible to moderately control the movement of unnecessary charges between them. Specifically, due to the presence of the intermediate layer, it is possible to efficiently block hole injection from the substrate to the photosensitive layer, or to reduce blocking properties against electrons from the photosensitive layer.

(3) Photosensitive layer The photosensitive layer is a part having a charge generation function and a charge transport function. In addition to a single layer structure in which both functions are applied to one layer to form a latent image, an area where two functions act Some of them have a functionally separated type layer structure. In the function separation type structure, the charge generation function is made to function in the charge generation layer (CGL), and the charge transport function is made to function in the charge transport layer (CTL).

  By adopting a function-separated type layer structure, it is possible to control the increase in residual potential with repeated use and to easily control other electrophotographic characteristics according to the purpose. The negatively charged photoreceptor preferably has a laminated structure in which a charge generation layer (CGL) is provided on an intermediate layer and a charge transport layer (CTL) is provided thereon. Conversely, a positively charged photoreceptor preferably has a laminated structure in which a charge transport layer (CGL) is provided on an intermediate layer and a charge generation layer (CGL) is provided thereon.

(Charge generation layer)
The charge generation layer contains a charge generation material (CGM) dispersed therein. In the present invention, it is particularly preferable to use a charge generation material having high sensitivity characteristics in a wavelength region of 350 nm to 500 nm. Examples of such charge generating substances include perylene compounds such as azo pigments and perylene pigments, and polycyclic quinone compounds such as polycyclic quinone pigments.

  Polycyclic quinoline compounds include compounds such as anthanthrone, pyranthrone, violanthrone, isoviolanthrone, diphthaloylpyrene, dinaphthopyrenequinone, and perylene compounds include perylene derivatives having a perylene or bisperylene skeleton. is there.

  A known resin binder can be used for the charge generation layer in order to disperse the charge generation material. Examples of the binder resin include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, and phenoxy resin.

(Charge transport layer)
The charge transport layer is a layer having a function of transporting charge carriers generated in the charge generation layer by exposure to the surface of the photoreceptor when exposed to a negatively charged photoreceptor. The charge transport layer contains a charge transport material (CTM), and may contain a binder made of a known resin in order to improve the dispersibility of the charge transport material.

  As the charge transport material (CTM), the compound represented by the general formula (4) or (5) is preferably used, and a known charge transport material (CTM) such as a hydrazone compound, a styryl compound, or a benzidine compound is used in combination. It is also possible to do. As the binder resin that can be used for the charge transport layer (CTL), known resins such as thermoplastic resins and thermosetting resins can be used.

  The full-color image forming method according to the present invention can be carried out using a two-component developer composed of a carrier and a toner, or a non-magnetic one-component developer composed only of a toner.

  When used as a two-component developer, for example, a full-color print can be created at high speed using a tandem image forming apparatus described later.

  Carriers that are magnetic particles used when used as a two-component developer are conventionally known, for example, metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead. It is possible to use materials. Among these, ferrite particles are preferable. The carrier has a volume average particle size of preferably 15 to 100 μm, more preferably 25 to 80 μm.

  Further, when used as a non-magnetic one-component developer that forms an image without using a carrier, the toner is slid and pressed against the charging member and the developing roller surface during image formation to be charged. The image formation by the non-magnetic one-component development method can simplify the structure of the developing device, and has an advantage that the entire image forming device can be made compact. Therefore, by adopting the non-magnetic one-component development method, it is possible to create a full-color print with a compact color printer, and it is possible to create a full-color print excellent in color reproducibility even in a working environment where space is limited.

Next, an image forming apparatus capable of implementing the full color image forming method according to the present invention will be described. First, a full-color image forming method according to the present invention includes at least the following steps. That is,
(1) An electrostatic latent image forming step for forming an electrostatic latent image on an electrostatic latent image carrier (photoconductor) using exposure light having a wavelength of 350 nm or more and 500 nm or less. (2) The toner according to the present invention is contained. (3) Toner formed on the electrostatic latent image carrier by developing the electrostatic latent image formed on the electrostatic latent image carrier to form a toner image using the developer thus formed. (4) A fixing step of fixing the toner image transferred onto the transfer body.

  In addition, you may have other processes other than the said 4 processes. For example, it is preferable to have a cleaning step of removing toner remaining on the surface of the electrostatic latent image carrier after transferring the toner image. In the transfer step, the toner image may be transferred from the electrostatic latent image carrier onto the recording medium via an intermediate transfer member.

  In the present invention, a latent image is formed by irradiating exposure light having a wavelength of 350 nm to 500 nm, generally called short wavelength exposure, and a semiconductor laser or a light emitting diode is used as an exposure light source. From these exposure light sources, exposure light having an exposure dot diameter of 5 to 30 [mu] m, preferably 15 to 20 [mu] m in the writing principal direction is irradiated onto the photoconductor to perform digital exposure. By such exposure means, a dot latent image of 1200 to 6000 dpi (dpi: number of dots per inch, 1 inch = 2.54 cm) is formed on the photosensitive member, so that high-resolution image formation can be performed. .

Here, the exposure dot diameter is the length of the exposure light, specifically, the length along the main scanning direction of the region where the intensity of the exposure light is 1 / e ² or more of the peak intensity. It means something. If the exposure dot diameter is smaller than the thickness of the photosensitive layer, the resolution of the latent image is increased. However, if the exposure dot diameter is too small, the reproducibility of the toner development amount may become unstable.

  FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus capable of forming a full-color image by a two-component development method.

  In FIG. 1, 1Y, 1M, 1C, 1K are photosensitive members, 4Y, 4M, 4C, 4K are developing devices (developing means), 5Y, 5M, 5C, 5K are primary transfer rolls as primary transfer means, 5A is a secondary transfer roll as a secondary transfer means, 6Y, 6M, 6C and 6K are cleaning devices, 7 is an intermediate transfer body unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer body.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. It has an endless belt-like paper feeding and conveying means 21 for conveying and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed above the main body A of the image forming apparatus.

  An image forming unit 10Y that forms a yellow image as one of the different color toner images formed on each photoconductor is arranged around a drum-shaped photoconductor 1Y as the first photoconductor and the photoconductor 1Y. The charging unit 2Y includes an exposure unit 3Y that irradiates the surface of the photoreceptor with exposure light having a wavelength of 350 nm to 500 nm, a developing unit 4Y, a primary transfer roll 5Y as a primary transfer unit, and a cleaning unit 6Y.

  The image forming unit 10M that forms a magenta image as another different color toner image includes a drum-shaped photoconductor 1M as a first photoconductor, and a charge disposed around the photoconductor 1M. Means 2M, exposure means 3M, developing means 4M, primary transfer roll 5M as primary transfer means, and cleaning means 6M.

  In addition, an image forming unit 10C that forms a cyan image as one of toner images of different colors is a drum-shaped photoconductor 1C as a first photoconductor, and a charge disposed around the photoconductor 1C. Means 2C, exposure means 3C, developing means 4C, primary transfer roll 5C as primary transfer means, and cleaning means 6C.

  Further, the image forming unit 10K that forms a black image as one of the other different color toner images includes a drum-shaped photoconductor 1K as a first photoconductor, and a charge disposed around the photoconductor 1K. Means 2K, exposure means 3K, developing means 4K, primary transfer roll 5K as primary transfer means, and cleaning means 6K.

  The endless belt-like intermediate transfer body unit 7 has an endless belt-like intermediate transfer body 70 as an intermediate transfer endless belt-like second image carrier that is wound around a plurality of rolls and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rolls 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rolls 22 A, 22 B, 22 C, 22 D, and a registration roll 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roll 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the heat roll type fixing device 24, is sandwiched by the paper discharge roll 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roll 5A, the residual toner is removed by the cleaning unit 6A from the endless belt-shaped intermediate transfer body 70 in which the recording member P is separated by curvature.

  During the image forming process, the primary transfer roll 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rolls 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, 1C, and 1R, respectively, only during color image formation.

  The secondary transfer roll 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roll 5A and secondary transfer is performed.

  In this manner, toner images are formed on the photoreceptors 1Y, 1M, 1C, 1R, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70 and recorded collectively. The image is transferred to the member P and fixed by the fixing device 24 by pressure and heating. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above-described charging, exposure, and development cycle. The next image formation is performed.

  The full-color image forming method using a non-magnetic one-component developer includes, for example, image formation in which the developing means 4 for the two-component developer described above is replaced with a known developing means for a non-magnetic one-component developer. This can be realized by using an apparatus.

  Further, the fixing method that can be carried out by the full-color image forming method according to the present invention is not particularly limited, and can be handled by a known fixing method. Known fixing methods include a roller fixing method comprising a heating roller and a pressure roller, a fixing method comprising a heating roller and a pressure belt, a fixing method comprising a heating belt and a pressure roller, and a heating belt and a pressure belt. There are belt fixing methods, and any method may be used. As a heating method, a known heating method such as a halogen lamp method or an IH fixing method can be adopted.

  The recording material (transfer paper) that can be used in the full-color image forming method according to the present invention is a support capable of holding a color toner image. Specifically, various types of support such as coated paper such as plain paper, fine paper, art paper, or coated paper from thin paper to thick paper, commercially available Japanese paper or postcard paper, plastic film for OHP, cloth, etc. The body can be mentioned, but is not limited thereto.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example. In the following text, “part” represents “part by mass”.

1. Production of “Photoreceptors 1-3” (1) Production of “Photoreceptor 1” A laminated structure in which an intermediate layer, a charge generation layer, and a charge transport layer are sequentially formed on a cylindrical support by the following procedure. The “photoreceptor 1” having the above was produced.

  First, the surface of the cylindrical aluminum support was cut so that the ten-point surface roughness Rz was 0.81 μm, and then a cleaning process was performed to prepare a conductive support.

<Formation of intermediate layer>
On the said electroconductive support body, the intermediate | middle layer coating liquid which consists of the following component was apply | coated by the dip coating method, and the intermediate | middle layer with a dry film thickness of 5 micrometers was formed by drying for 30 minutes at the temperature of 120 degreeC. The intermediate layer coating solution was prepared by performing the following procedure, diluting it twice with the same solvent mixture used during the preparation, allowing it to stand overnight, and then filtering. is there. Filtration was performed under a pressure of 50 kPa using a “rigid mesh filter (manufactured by Nippon Pole Co., Ltd.)” having a nominal filtration accuracy of 5 μm.

    Binder resin (polyamide resin with the following structure) 1.0 part

Rutile-type titanium oxide (primary particle size 35 nm; surface treatment with dimethylpolysiloxane having a hydroxyl group at the terminal and the hydrophobicity adjusted to 33) 5.6 parts ethanol / n-propyl alcohol / tetrahydrofuran mixed solution (Mass ratio; 45/20/30) 10 parts After mixing the above components, a dispersion is prepared by batch-type dispersion using a sand mill disperser for 10 hours. Was made.

<Formation of charge generation layer>
Charge generation material (compound with the following structure) 24 parts

Polyvinyl butyral resin “ESREC BL-1 (manufactured by Sekisui Chemical Co., Ltd.)”
12 parts 2-butanone / cyclohexanone mixed solution (volume ratio; 4/1) 300 parts After the above composition was mixed, a dispersion treatment was performed using a sand mill disperser to prepare a charge generation layer coating solution. Using this coating solution, a charge generation layer was formed by coating on the intermediate layer by a dip coating method such that the film thickness upon drying was 0.5 μm.

<Preparation of charge transport layer>
Charge transport material (Exemplary Compound CTM26) 225 parts Polycarbonate “Z300 (Mitsubishi Gas Chemical Co., Ltd.)” 300 parts Antioxidant “Irganox 1010 (Nippon Ciba Geigy)” 6 parts Tetrahydrofuran / toluene mixture (volume ratio; 3 / 1) 2000 parts Silicon oil “KF-96 (manufactured by Shin-Etsu Chemical Co., Ltd.)” 1 part After the above composition was mixed, a dispersion treatment was performed using a sand mill disperser to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and subjected to a drying process at a temperature of 120 ° C. for 70 minutes to form a charge transport layer having a thickness of 20.0 μm at the time of drying. In this way, “Photoreceptor 1” was produced.

(2) Production of “Photoreceptors 2 and 3” In the production of “Photoreceptor 1”, the charge generation material was changed to “CGM2-17” shown below, and the charge transport material was changed to “CTM31” described above. Otherwise, “Photoreceptor 2” was prepared in the same procedure.

  In addition, “Photoreceptor 3” was prepared in the same manner as in “Photoreceptor 1” except that the charge generation material was changed to “CTM-R1” shown below.

2. Preparation of Toner 2-1 Preparation of “Colorant Particle Dispersion” (1) Preparation of “Yellow Colorant Particle Dispersion Y1” 7.0 parts by mass of sodium n-dodecyl sulfate was added to 160 parts by mass of ion-exchanged water. A surfactant aqueous solution was prepared by dissolving with stirring. In this surfactant aqueous solution,
C. I. Pigment Yellow 74 22.5 parts by mass C.I. I. 2.5 parts by weight of Pigment Yellow 139 was gradually added, and then dispersion treatment was performed using “CLEARMIX W Motion CLM-0.8 (M Technique Co., Ltd.)” to obtain “Yellow Colorant Particle Dispersion Y1”. Was prepared.

(2) Preparation of “yellow colorant fine particle dispersions 2 to 4”, “magenta colorant fine particle dispersions 1 to 4”, and “cyan colorant fine particle dispersions 1 to 4” “Yellow colorant fine particle dispersions 1” “Yellow colorant fine particle dispersions 2 to 4” were prepared by the same procedure except that the type and addition amount of the yellow colorant were changed as shown in Table 2. In addition, the same procedure was followed except that the yellow colorant used in the preparation of “Yellow Colorant Fine Particle Dispersion 1” was replaced with a magenta colorant of the type and addition amount shown in Table 3. Fine particle dispersions 1 to 4 "were prepared. Further, the procedure of “Cyan Colorant” was changed in the same manner except that the yellow colorant used in the preparation of “Yellow Colorant Fine Particle Dispersion 1” was changed to use the kind and addition amount of cyan colorant shown in Table 4. Fine particle dispersions 1 to 4 "were prepared.

2-2. Preparation of “Toners 1Y to 4Y, 1M to 4M, 1C to 4C” (1) Preparation of “Resin Particle 1” (a) First-stage polymerization A reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device An aqueous surfactant solution was prepared by dissolving 8 parts by mass of an anionic surfactant (sodium dodecyl sulfate) in 3000 parts by mass of ion-exchanged water.

  While stirring the surfactant aqueous solution at a stirring speed of 230 rpm under a nitrogen stream, the temperature was raised to 80 ° C. After the temperature increase, a solution in which 10 parts by mass of potassium persulfate (KPS) was dissolved in 200 parts by mass of ion-exchanged water was added, the temperature of the liquid was adjusted again to 80 ° C., and a polymerizable monomer solution consisting of the following compounds: Was added dropwise over 1 hour.

Styrene 480 parts by weight n-butyl acrylate 250 parts by weight Methacrylic acid 68 parts by weight n-octyl-3-mercaptopropionate 16 parts by weight After dropping the polymerizable monomer solution, the mixture is heated and stirred at 80 ° C. for 2 hours. As a result, a polymerization reaction (first-stage polymerization) was performed to prepare a “resin particle dispersion (1H)” containing “resin particles (1H)”.

(B) Second-stage polymerization In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device, 7 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate was dissolved in 800 parts by mass of ion-exchanged water, and the interface An aqueous activator solution was prepared.

  While stirring the aqueous surfactant solution at a stirring speed of 230 rpm under a nitrogen stream, the temperature is heated to 98 ° C., and then 260 parts by mass (in terms of solid content) of the “resin particle dispersion (1H)” and the following compound are included. A solution in which the polymerizable monomer solution was dissolved at 90 ° C. was added.

Styrene 245 parts by mass n-butyl acrylate 120 parts by mass n-octyl-3-mercaptopropionate 1.5 parts by mass Paraffin wax (melting point 45 ° C.) 190 parts by mass After adding the monomer solution containing the paraffin wax, An oil droplet particle dispersion was prepared by mixing and dispersing for 1 hour using a mechanical disperser “CLEAMIX (M Technique Co., Ltd.)” having a circulation path.

  Next, a polymerization initiator solution in which 6 parts by mass of potassium persulfate is dissolved in 200 parts by mass of ion-exchanged water is added to the oil droplet particle dispersion, and the mixture is heated and stirred at 98 ° C. for 1 hour. Two-stage polymerization) was performed. A “resin particle dispersion (1HM)” containing “resin particles (1HM)” was produced by the polymerization reaction.

(C) Third-stage polymerization A solution of 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water is added to the “resin particle dispersion (1HM)”, and a polymerizable monomer solution comprising the following compounds: Was dripped over 1 hour under the temperature condition of 80 degreeC.

Styrene 435 parts by weight n-butyl acrylate 130 parts by weight Methacrylic acid 33 parts by weight n-octyl-3-mercaptopropionate 8 parts by weight After the dropwise addition of the polymerizable monomer solution, the polymerization reaction is carried out by stirring for 2 hours. The third stage polymerization) was performed, and then cooled to 28 ° C. to prepare “Resin Particle Dispersion 1” containing “Resin Particles 1”. “Resin particles 1” were prepared by the above procedure.

(2) Production of “Toner 1Y” (a) Aggregation / fusion process In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device,
420.7 parts by mass of resin particles 1 (solid content conversion)
Ion-exchanged water 500 parts by mass Yellow colorant particle dispersion Y1 5.3 parts by mass (solid content conversion)
Was added to adjust the internal temperature to 30 ° C. while stirring, and then the pH was adjusted to 10 by adding a 5 mol / liter aqueous sodium hydroxide solution.

  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 to aggregate the particles. Subsequently, when the average particle diameter of the aggregated particles was measured with “Coulter Multisizer 3 (manufactured by Beckman Coulter)” and the volume-based median diameter reached 6.5 μm, 8.2 parts by mass of sodium chloride was exchanged with ion-exchanged water. An aqueous solution dissolved in 50 parts by mass 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 producing “Toner Particle Dispersion 1Y”.

(C) Washing / Drying Step Next, the produced “toner particle dispersion 1Y” was filtered, and the washing treatment was repeated using ion-exchanged water at 45 ° C. After completion of the cleaning treatment, drying treatment was performed with hot air at 40 ° C. to produce “toner particles 1Y” having a volume-based median diameter of 6.2 μm.

(2) Preparation of “Toner Particles 2Y-4Y”, “Toner Particles 1M-4M”, “Toner Particles 1C-4C” Instead of “Yellow Colorant Particle Dispersion Y1” used in the preparation of “Toner Particles 1Y” “Toner particles 2Y to 4Y” were prepared in the same procedure except that the “yellow colorant particle dispersions 2 to 4” shown in Table 2 were changed.

  Further, the “yellow magenta colorant fine particle dispersion liquid 1” used in the preparation of the “yellow toner particle 1” was replaced with the “magenta colorant fine particle dispersion liquids 1 to 4” shown in Table 3 described above. “Magenta toner particles 1M to 4M” were prepared according to the procedure.

  Further, in place of “Yellow colorant fine particle dispersion 1” used in the preparation of “Yellow toner particles 1”, the same procedure as in “Cyan colorant fine particle dispersions 1 to 4” shown in Table 4 was used. “Cyan toner particles 1C to 4C” were prepared according to the procedure.

  The volume-based median diameters of “toner particles 2Y to 4Y”, “toner particles 1M to 4M”, and “toner particles 1C to 4C” were all 6.2 μm, similar to “toner particles 1Y”.

(3) External Addition Treatment Silica (average primary particle size 12 nm) treated with the following external additive hexamethylsilazane was added to the prepared “toner particles 1Y to 4Y”, “toner particles 1M to 4M”, and “toner particles 1C to 4C”. )
0.6 part by mass n-octylsilane-treated titanium dioxide (average primary particle size 24 nm)
0.8 parts by weight were added. The external addition process was performed by using a “Henschel mixer (manufactured by Mitsui Miike Mining Co., Ltd.)” and mixing them under the conditions of a stirring blade peripheral speed of 35 m / second, a processing temperature of 35 ° C., and a processing time of 15 minutes. In this manner, “toners 1Y to 4Y”, “toners 1M to 4M”, and “toners 1C to 4C” were produced. In the produced “Toners 1Y to 4Y”, “Toners 1M to 4M”, and “Toners 1C to 4C”, no change was observed in the volume-based median diameter before and after the external addition process.

  The types and ratios of the colorants used in “Toners 1Y to 4Y”, “Toners 1M to 4M” and “Toners 1C to 4C” produced by the above procedure, the maximum saturation of the toner image, and the brightness at the maximum saturation And the reflectance in each predetermined wavelength is shown in Table 5-Table 7 mentioned later.

3. Evaluation 3-1. Preparation of Developer Each of “Toner 1Y to 4Y”, “Toner 1M to 4M” and “Toner 1C to 4C” was mixed with a ferrite carrier having a volume average particle diameter of 50 μm coated with methyl methacrylate and cyclohexyl methacrylate resin. A developer having a toner concentration of 6% was prepared. That is, yellow “Developers 1Y to 4Y”, magenta “Developers 1M to 4M”, and cyan “Developers 1C to 4C” were prepared.

3-2. Evaluation Experiment The prepared developer was mounted on a remodeling machine of a commercial digital copying machine “bizhub 920 (manufactured by Konica Minolta Business Technologies, Inc.)” corresponding to the two-component development type image forming apparatus of FIG. The digital copying machine can form an image by using a semiconductor laser having a wavelength of 405 nm as an exposure light source, setting the beam diameter under conditions capable of 1200 dpi exposure, and charging the surface potential of the photoreceptor to -700V. I did it.

(1) Evaluation experiment 1 (Brightness evaluation of toner image)
Using the image forming apparatus, yellow “developers 1Y to 4Y”, magenta “developers 1M to 4M”, and cyan “developers 1C to 4C” are used to form a yellow toner image composed only of each toner. A magenta toner image and a cyan toner image were output. The brightness was measured and evaluated.

  The brightness at the maximum saturation of each output toner image was measured using a spectrophotometer “Gretag Macbeth Spectrolino (manufactured by Gretag Macbeth)”. Measurements were made using a D65 light source as the light source and a φ4 mm reflective measurement aperture, with a measurement wavelength range of 380 to 730 nm at 10 nm intervals, a viewing angle (observer) of 2 °, and a dedicated white tile as a reference. went.

Each toner image is output on a transfer paper “POD gloss sheet paper (manufactured by Oji Paper Co., Ltd.)” having a basis weight of 128 g / m ² and a lightness of 93.

  Tables 5 to 7 show the lightness at the maximum saturation of the toner image formed only with each toner.

(2) Evaluation experiment 2 (image formation performance evaluation)
As shown in Tables 8 and 9, the image forming apparatus includes the “photosensitive members 1 to 3”, the yellow “developers 1Y to 4Y”, the magenta “developers 1M to 4M”, and the cyan color. “Developers 1C to 4C” were combined, and 35 types of image forming conditions were set to create a print. Of the 35 types of image forming conditions, those having the configuration of the present invention were designated as “Examples 1 to 38”, and those having no configuration of the present invention were designated as “Comparative Examples 1 to 5”. The evaluation was performed on the following items in an environment of a temperature of 20 ° C. and a humidity of 50% RH.

<Evaluation of halftone image quality (graininess, homogeneity)>
The “Image Imaging Test Chart No. 3” sample number 5-1 (color continuous tone portrait and color gradation batch) issued by the Japan Imaging Society First Section was output and image evaluation was performed visually. Focusing on the skin color of the person and the moist feeling of the groom image, evaluation was made based on the following criteria, and ◎ and ○ were accepted.

(Evaluation criteria)
A: Graininess is not felt at all visually. In addition, when the space between the dots was observed with a magnifying glass of 20 times, no toner particles that cause dust were observed. Alternatively, when the space between the dots was observed with a 20 × magnifier, 1 to 3 toner particles causing dust were confirmed. ×: Compared with the image of “Rank ○”, a feeling of roughness was visually observed. Or, when the space between the dots was observed with a 20 times loupe, toner particles that caused dust were present so that it was difficult to count.

<Evaluation of graininess of soft tone image>
Graininess was evaluated using the following soft tone image. Here, the soft tone (Soft Tone) is a color tone classified as a color that creates a gentle and gentle atmosphere by adding a slight dullness to a bright color.

Evaluation is from Web Safe Color,
8 color soft tones; # cc6666, # cc9966, # cccc66, # 99cc66, # 66cc66, # 66cc99, # 66cccc, # 6699cc
The patch images were output in the printer mode, and the granularity of each image was comprehensively evaluated based on the following evaluation criteria.

(Evaluation criteria)
◎: When observed with a magnifying glass at a magnification of 10 times, it was confirmed that fine and uniform halftone images were reproduced on all patch images. ○: The graininess of all patch images is not problematic with the naked eye. When observed with a magnifying glass having a magnification of 10 times, some graininess slightly appears. Δ: Although there is a patch image in which some graininess is confirmed with the naked eye, it is determined that the image is within an allowable range. In some cases, the graininess is confirmed, and there is an image that looks like a rough image.

The computer display conditions for displaying the soft tone image are as follows. That is,
(Computer display condition)
・ Computer: iMAC (Apple Computer Co., Ltd.)
・ 24-inch wide screen liquid crystal display screen ・ Screen resolution: 1920 × 1200 pixels ・ 2.16 GHz Intel Core 2 Duo processor 1
・ 4MB shared L2 cache ・ 1GB memory (2 × 512MB SO-DIMM)
・ 250GB serial ATA hard drive 2
・ 8x double layer SuperDrive (DVD + R DL, DVD ± RW, CD-RW)
・ NVIDIA GeForce 7300 GT 128MB GDDR3 memory ・ AirMac Extreme and Bluetooth 2.0 built-in ・ Apple Remote
<Evaluation of graininess of dull tone image>
Graininess was evaluated using the following dull tone image. Here, “Dull Tone” is a color tone classified as a color representing a gentle and slightly complex expression obtained by adding a slight dullness to a bright color.

Evaluation is from Web Safe Color,
6 colors of dull tone; # 996666, # 999966, # 669966, # 6669999, # 666699, # 996699
The patch images were output in the printer mode, and the granularity of each image was comprehensively evaluated based on the same evaluation criteria as the evaluation of the granularity of the soft tone. The computer display conditions for displaying six-color dull tone patch images are the same as those for displaying the soft tone patch images.

<Image density stability>
10,000 continuous prints were performed under each condition, and changes in density of yellow, magenta, cyan, red, green, and blue images before and after the continuous print were evaluated. In the evaluation, a solid image with an initial image density of 1.20 was output before and after continuous printing, the output solid part density was measured five times, an average value was calculated, and the density change before and after continuous printing was evaluated. . The image density was measured using a color reflection densitometer “RD-917 (manufactured by Macbeth)”. In the evaluation criteria shown below, ◎ and ○ were accepted. That is,
(Evaluation criteria)
A: Density difference is 0.08 or less. O: Density difference is larger than 0.08 and 0.15 or less. X: Density difference is larger than 0.15.

  The results are shown in Tables 8 and 9.

  As shown in Tables 8 and 9, “Examples 1 to 38” having the configuration of the present invention obtained results satisfying the regulations for any of the evaluation items. On the other hand, in “Comparative Examples 1 to 5” that do not have the configuration of the present invention, any evaluation item did not satisfy the regulation. As described above, it was confirmed that there was a significant difference in the image quality of the toner images produced between those satisfying the configuration of the present invention and those not satisfying the configuration.

  In addition, when the exposure light was changed to a semiconductor laser with a wavelength of 350 nm and a semiconductor laser with a wavelength of 500 nm and the same evaluation was performed, the same result as above was obtained.

1 is a schematic diagram illustrating an example of a tandem full-color image forming apparatus capable of image formation by a two-component development system.

Explanation of symbols

1 (1Y, 1M, 1C, 1K) Photoconductor 2 (2Y, 2M, 2C, 2K) Charging unit 3 (3Y, 3M, 3C, 3K) Exposure unit 4 (4Y, 4M, 4C, 4K) Developing unit 5 ( 5Y, 5M, 5C, 5K, 5A) Transfer roll 6 (6Y, 6M, 6C, 6K) Cleaning device 7 Intermediate transfer unit 10 (10Y, 10M, 10C, 10K) Image forming unit 24 Heat roll fixing device 70 Intermediate Transcript

Claims (6)

An electrostatic latent image is formed on the organic photoreceptor by exposing the organic photoreceptor using a light source having a wavelength of 350 nm or more and 500 nm or less, and the electrostatic latent image formed on the organic photoreceptor is at least A full-color image forming method in which development is performed using yellow toner, magenta toner, and cyan toner, a toner image formed on the organic photoreceptor is transferred onto a transfer body, and then the toner image is fixed to form a full-color image. Because
When the toner image formed with only the yellow toner has the maximum saturation, the lightness L ^* _Y is in the range of 80 to 90,
When the toner image formed only with the magenta toner has the maximum saturation, the lightness L ^* _M is in the range of 35 to 51,
A full-color image forming method, wherein a lightness L ^* _C is in a range of 53 to 70 when the toner image formed only of the cyan toner has maximum saturation. The full-color image forming method according to claim 1, wherein the magenta toner contains a compound represented by the following general formula (1).

[Wherein R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₇ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₁₅ and R ₁₆ each independently represent a hydrogen atom or carbon number. 1 or 2 alkyl groups are represented. M and n represent an integer of 1 or 2, and (X ⁻ ) represents a counter anion and represents a chlorine ion or a sulfonic acid compound ion. ] The full-color image forming method according to claim 1, wherein the magenta toner contains a compound represented by the following general formula (2).

[In the formula, each R ₂₁ independently represents a hydrogen atom or a substituent, R ₂₂ represents —NR ₂₄ R ₂₅ or —OR ₂₆ , and R ₂₃ represents a hydroxyl group, an alkoxy group, an aryloxy group, an amino group, an amide group, an alkylsulfonylamino group. Represents any group of an arylsulfonylamino group. A ₁₁ to A ₁₃ each independently represent a _{-CR 27} = or -N =.
X ₁₁ is an atomic group necessary for forming a 5- or 6-membered aromatic ring or heterocyclic ring, Z ₁ is a substituent necessary for forming a 5- or 6-membered heterocyclic ring containing at least one nitrogen atom And a condensed ring may be formed by the substituent. R _{24 to} R ₂₇ each independently represents a hydrogen atom or a substituent, L ₁₁ represents a linking group having 1 or 2 carbon atoms or a part of a ring structure, and is bonded to R ₂₃ to form a 5- or 6-membered ring structure. May be. p represents an integer of 0 to 3. ] The full-color image forming method according to claim 1, wherein the cyan toner contains a compound represented by the following general formula (3).

[In the formula, each Z independently represents a hydroxy group, a chlorine group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following general formula (3-1). Show. A ^{1 to} A ⁴ represent a benzene ring. ]

[Wherein R ⁶¹ , R ⁶² , and R ⁶³ represent an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or an aryloxy group having 6 to 18 carbon atoms. Indicates a group. R ⁶¹ , R ⁶² and R ⁶³ may be the same group or different groups. ] The full-color image forming method according to any one of claims 1 to 4, wherein the organic photoreceptor contains a compound represented by the following general formula (4) as a charge transport material.

[Wherein R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 5 carbon atoms or an alkoxy group, and R ₃ and R ₄ may have a substituent. N represents an integer of 0 to 2, m represents an integer of 0 to 3, and l and m represent an integer of 0 to 5. A, B, C and D represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, and A, B, C and D are not simultaneously a hydrogen atom. ] The full-color image forming method according to any one of claims 1 to 4, wherein the photoreceptor contains a compound represented by the following general formula (5).

_{Wherein, R 5, R 6, R} 7 and _{R 8} represents an alkyl group or an alkoxy group having 1 to 5 carbon atoms. P represents an integer of 0 to 5, q represents an integer of 0 to 4, r represents an integer of 0 to 2, and s represents an integer of 0 to 3. A, B, C and D represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, and A, B, C and D are not simultaneously a hydrogen atom. ]

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