JP2001175022A - Electrostatic latent image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner giving a high quality image excellent in color tone, free from roughness in the low density part, excellent in gradation and having a slight difference in glossy appearance due to image density. SOLUTION: The electrostatic latent image developing toner is a transparent toner used in a color image forming method using Y, M, C and BK toners and the transparent toner and the storage modulus G' 1 of the transparent toner obtained by measuring the dynamic viscoelasticity of the toner at 140 deg.C is lower than the storage modulus G' 2 of one of the Y, M, C and BK toners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art In general, a full-color image is formed by digital electrophotography by optically converting a full-color image signal into three subtractive primary colors (yellow, magenta, and cyan, respectively; Y, M, and C, respectively) and black (hereinafter, BK). Generally, it is generally performed by electrically or electrically separating four color dot images, superimposing them on paper or an intermediate transfer body, and finally fixing and fixing them on transfer paper. In recent years, the full-color image quality of the electrophotographic system has been dramatically improved compared to the conventional art, but there is still room for improvement in the defect of an image unique to electrophotography.

Conventionally, in electrophotography, the minimum pixel diameter is larger than that of ordinary offset printing, and the pixel (dot) diameter is hard to be constant as the pixel density becomes higher and the pixel becomes smaller. , The number of pixels to be written is reduced.
There was a problem that the granularity of the image was different due to the difference in image density. In addition, since the degree of coloring per pixel is higher than in printing, an image having a rough highlight portion and a granular impression is likely to be formed.

In the high density area, Y (yellow), M
(Magenta) and C (cyan) toners are superimposed, and the white portion of the transfer paper, which is the background, is used. Therefore, the toner adhesion amount is naturally large in the high image density portion, and the highlight portion is used. Is smaller. As a result, particularly in the halftone dot image portion, light diffusely reflected at the background portion is more absorbed by the high-density toner layer, and the visual image density becomes higher than the dot area ratio of the image (so-called optical dot gain). This was conspicuous, and this also caused the lack of reproducibility in the highlighted portion.

[0005] Further, in a color image, a preferable image gloss differs depending on the type of image to be printed. For example, in a so-called high-definition photographic image such as a person or a landscape, if moderate image gloss is obtained, a high-quality texture is obtained and generally preferred. In a conventional electrophotographic method, a high image density portion and a low image density portion are used. The amount of toner adhesion at
Since the smoothness of the transfer paper surface and the toner image surface is significantly different, the glossiness differs depending on the image density. Therefore, in the image plane,
There was unevenness in image gloss, which caused the image to be uncomfortable. On the other hand, a character image often feels difficult to read when the gloss difference between the background portion and the image portion is large.

In order to solve these problems, conventionally, Y (yellow), M (magenta), C (cyan), B
In addition to K (black), a method of correcting gloss difference in an image surface, arbitrarily controlling gloss on the same transfer paper surface, and correcting image density and toner adhesion amount by using a transparent toner. Has been proposed. For example, the following may be mentioned.

Japanese Patent Application Laid-Open No. Hei 7-248662 proposes that a transparent toner is developed so that the total amount of the attached toner is constant.

Japanese Patent Application Laid-Open No. 8-106195 proposes, in a developing method using Y, M, C, BK and a transparent toner, developing the transparent toner in the first development.

Japanese Patent Application Laid-Open No. 9-200551 proposes that a transparent toner image is formed by using an inverted signal of the Y, M, C, and BK images.

Japanese Patent Application Laid-Open No. 10-123853 proposes a method in which a transparent toner layer is formed on an intermediate transfer member, and a chromatic toner image is formed thereon.

Japanese Patent Laid-Open No. Hei 10-207174 proposes to superimpose a transparent toner image on a chromatic toner image.

Japanese Patent Application Laid-Open No. H11-7174 proposes that the development amount of a transparent toner is changed in accordance with the surface roughness of a transfer object.

JP-A-5-232840 proposes a method of arbitrarily selecting the surface property of an image locally or entirely by using a transparent toner layer.

Japanese Patent Application Laid-Open No. 7-72696 discloses that a latent image position for developing a transparent toner and a development amount are controlled.

Japanese Patent Application Laid-Open No. 4-278967 proposes a method in which a transparent toner layer is provided on an intermediate transfer member, toner is transferred from the image forming member onto the transparent toner layer, and this is transferred and fixed on transfer paper.

All of these proposals propose an image forming method using a transparent toner (colorless and transparent toner as intended in the present invention). By increasing the amount of toner adhered to the image area, or by covering the entire image surface with a transparent toner to obtain uniform gloss, it is proposed to eliminate the discomfort of the conventional color image quality, In any of these known methods, unless the melting characteristics of the toner used are optimally controlled,
It did not exhibit the desired effect.

That is, usually, Y, M,
In the case of the transparent toner containing less or no colorant compared to the C and BK toners, the dynamic melting characteristics at the time of fixing are naturally different. Even if a transparent toner is used without properly controlling the melting characteristics, the image gloss mismatch between the chromatic image portion composed of the Y, M, C, and BK toners and the transparent toner portion, and the particle interface of the toner layer remains. This causes inconsistencies in the transparency, thereby deteriorating the image quality and causing image defects.

Japanese Patent Application Laid-Open Nos. Hei 4-204670 and Hei 8-220821 disclose the use of a chromatic toner and a transparent or white achromatic toner. It is proposed that the glossiness of the chromatic toner is different from that of the chromatic toner, and that the glossiness preferably differs by ± 20 or more.

However, in order to obtain gloss by this method, it is necessary to cover the entire image surface with transparent toner.
Due to the change in toner layer thickness due to image density,
It does not solve the above problem. Further, when a transparent toner is used for a part of an image, unevenness occurs in gloss of the image.

Japanese Patent Application Laid-Open No. 10-123863 proposes a toner containing at least one kind of fine particles in a transparent toner.

In this method, in order to change the glossiness of an image, the fixing conditions are changed to change the glossiness of the transparent toner, but even in this case, the glossiness of all the color toners is uniform. It is necessary to change, and even if the glossiness of the transparent toner changes, it is obvious that uneven glossiness of the image occurs depending on the fixing conditions.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which solves the above-mentioned problems. An object of the present invention is to provide a developer which is excellent in color reproducibility, has no graininess in a low density portion, has excellent gradation, and has a small difference in glossiness due to image density, and can obtain a high quality image.

[0023]

The present inventors have made intensive studies and found that this problem can be solved by using a colorless and transparent toner which does not affect the color tone and by suitably controlling the melting characteristics of the toner. I found what I could do.

That is, as described above, the problem of color image reproducibility in electrophotography is that a change in image density is accompanied by a change in toner volume of a pixel and a change in gloss. Therefore, it was effective to fill the low density portion adjacent to the high density color pixel with the transparent toner without any gap. In particular, the effect is remarkable when a transparent toner to be used is a toner having a lower viscosity when melted than other color toners. Also, superimposing the transparent toner on the low density image area,
Or, by forming a transparent toner layer on the bottom layer,
The change in the toner layer thickness between the adjacent high-density image area was reduced, and the unevenness on the image surface was reduced, so that uniform gloss could be provided on the entire image surface. By suitably controlling the viscosity at the time of melting, the interface between the transfer paper surface and the transparent toner is filled without gaps, so that the scattering of light incident on the transfer paper surface is reduced, and the colorant layer thickness is increased. It has been found that the increase in the visual image density is reduced.

That is, means for solving the above-mentioned problems are as follows:
It is as follows. 1) A transparent toner used in a color image forming method using Y, M, C, BK and further a transparent toner, and the storage elastic modulus G′1 obtained by dynamic viscoelasticity measurement at 140 ° C. of the toner. A toner for developing an electrostatic latent image characterized by having a storage elastic modulus G′2 smaller than that of any of the other toners of Y, M, C and BK.

2) In 1), when the reflection density I1 of the fixed image having an adhesion amount of 0.1 mg / cm ^{2 formed on} the transfer paper, the reflection density I2 of the transfer paper, and ΔI = | I1-I2 | 0.1
A substantially colorless electrostatic latent image developing toner, characterized by the following.

3) In 1), when the glossiness K1 of the fixed image formed on the transfer paper having the adhesion amount of 0.1 mg / cm ² , the reflection density K2 of the transfer paper, and ΔK = | K1-K2 | A substantially colorless electrostatic latent image developing toner, wherein the toner content is less than 20%.

4) The toner for developing an electrostatic latent image according to 1), wherein the transparent toner contains at least 60% by weight of a polyester resin.

5) The toner for developing an electrostatic latent image according to 1), wherein the transparent toner contains at least 60% by weight of a polyol resin.

6) The toner for developing an electrostatic latent image according to 1), wherein the transparent toner contains at least 0.01 μm to 0.1 μm of inorganic fine particles.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent toner used in the present invention is another color toner used simultaneously, namely, Y, M,
It has a lower storage elastic modulus at 140 ° C. than the toner of either C or BK. The storage elastic modulus of the transparent toner is defined as G′1, and the storage elastic modulus of the colored toner is defined as G′2. Y,
The respective storage elastic moduli of M, C, and BK may take different values.
G'2. Thus, the color toner can be fixed without causing collapse or fattening due to fixing, and the transparent toner can fill the low density portion.

The storage elastic modulus of each toner is measured as follows. Pressurize and shape the toner to be measured, diameter 20mm,
A pellet having a thickness of 0.5 mm is prepared. The amount of toner depends on the specific gravity of the toner and the compression pressure during pressurization and shaping.
It is about 0.1 to 0.5 g.

The measurement conditions are as follows. The measurement is performed by an oscillation using a parallel disk fixture having a measurement temperature of 140 ° C. and a diameter of 20 mm. The measurement gap is set to 0.75 mm in consideration of the thermal expansion of the toner, the distortion amount is set to 0.1%, and the measurement frequency is set to 100 rad / sec. The temperature is raised from a sample temperature of 25 ° C., measurement is started at 140 ° C. ± 3 ° C., and G ′ 30 seconds after the start of the measurement is defined as the storage elastic modulus of the toner to be measured. Pre-vibration shall not be applied to the sample before the start of the measurement. AUTOSTRAIN is not used.

It is most preferable that the transparent toner is completely colorless. However, the transparent toner may be slightly colored depending on the material constituting the toner. The coloring of the transparent toner is measured as follows. 0.1 mg / cm ² on transfer paper
To create a fixed image. The reflection density is measured with a Macbeth reflection densitometer using a B / W filter. Fixed image measurement
When I1 and the reflection density I2 of the transfer paper, and ΔI = | I1-I2 |, it is preferable that ΔI is 0.1 or less. Exceeding this value undesirably reduces the color reproduction range of the image area using the transparent toner.

Similarly, the glossiness K1 of the fixed image having an adhesion amount of 0.1 mg / cm ^{2 formed} on the transfer paper with the transparent toner, the reflection density K2 on the transfer paper with another color toner, ΔK = | K1
When -K2 |, the glossiness of the entire image area can be made uniform by setting ΔK to be less than 20%.

The gloss is measured at an incident angle of 60 ° using a variable-angle gloss meter. When ΔK exceeds 20%, the gloss difference between the high-density part and the low-density part becomes large even if the transparent toner is overlaid on the low-density part, and the desired effect cannot be obtained.

As the constituent materials of the toner used in the present invention, conventionally used thermoplastic resins and, if necessary,
It is possible to incorporate suitable dyes and pigments, agents having charge control properties, and materials exhibiting lubricity and releasability. Above all, it is preferable to contain a polyester resin as a main component in an amount of 60% by weight or more for suitably controlling the viscosity of the toner.

As the polyester resin used in the present invention, all resins obtained by a generally known polycondensation reaction between an alcohol and an acid are used.

The acid value can be controlled by a generally known method. For example, alcohols include diols such as polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, and 1,4-butenediol; 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A,
Etherified bisphenols such as polyoxyethylenated bisphenol A and polyoxypropylene bisphenol A; dihydric alcohol units obtained by substituting these with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms; and other divalent alcohols Alcohol unit of sorbitol, 1,
2,3,6-hexanetetrol, 1,4-sarbitan, pentaethritol dipentaethritol, tripetaesritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentane Triol, glycerol,
2-methylpropanetriol, 2-methyl-1,2,2
Higher trivalent or higher alcohol monomers such as 4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

The carboxylic acids used to obtain the polyester resin include, for example, monocarboxylic acids such as palmitic acid, stearic acid and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid and cyclohexanedicarboxylic acid. Acids, succinic acid, adipic acid, sebacic acid, malonic acid, which have 3 to 22 carbon atoms
Divalent organic acid monomers substituted with saturated or unsaturated hydrocarbon groups, anhydrides of these acids, dimers of lower alkyl esters and linoleic acid, 1,2,4-benzenetricarboxylic acid, , 2,5-benzenetricarboxylic acid,
2,5,7-naphthalenetricarboxylic acid, 1,2,4-
Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid,
3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid embol trimer acid, trivalent such as anhydride of these acids These are the polyvalent carboxylic acid monomers described above.

Also, a polyol resin is used as a main component in 60
It is also preferable that the content is not less than% by weight, since a suitable viscosity can be similarly obtained.

As the polyol resin, various types can be used.
The following are particularly preferred. Particularly, as a polyol resin, an epoxy resin, an alkylene oxide adduct of a dihydric phenol or a glycidyl ether thereof, a compound having one active hydrogen that reacts with an epoxy group in the molecule, and an active hydrogen that reacts with an epoxy group in the molecule. It is preferable to use a polyol obtained by reacting a compound having two or more compounds with each other. Furthermore, this epoxy resin has at least two kinds of bisphenol A having different number average molecular weights.
It is particularly preferred that it is a type epoxy resin. This polyol resin gives good gloss and transparency, and is effective in offset resistance.

In the present invention, when a conventionally known copolymer of styrene and a vinyl monomer is used,
A polymer composed of all conventionally known monomers is used.

Specific examples include the following monomers. That is, styrene and its derivatives, for example, methylstyrene, dimethylstyrene, trimethylstyrene,
Alkyl styrenes such as ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene, and nitro Styrene, acetylstyrene, methoxystyrene and the like can be mentioned.

Also, addition-polymerizable unsaturated carboxylic acids, ie, addition-polymerizable unsaturated aliphatic monocarboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, isocrotonic acid, tiglic acid, and angelic acid. Or an addition-polymerizable unsaturated aliphatic dicarboxylic acid such as maleic acid, fumaric acid, itaconic acid or mesaconic acid. Further, a metal salt of a carboxylic acid can be used, and the metal salification can be performed after the polymerization.

Further, the addition polymerizable unsaturated carboxylic acid and alkyl alcohol, halogenated alkyl alcohol,
Examples thereof include an esterified product with an alcohol such as an alkoxyalkyl alcohol, an aralkyl alcohol and an alkenyl alcohol. Specific examples of the alcohol include alkyl alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, and hexadecyl alcohol; Halogenated alkyl alcohols obtained by partially halogenating these alkyl alcohols; alkoxyalkyl alcohols such as methoxyethyl alcohol, ethoxyethyl alcohol, methoxypropyl alcohol and ethoxypropyl alcohol; aralkyl alcohols such as benzyl alcohol, phenylethyl alcohol and phenylpropyl alcohol; Alke such as allyl alcohol and crotonyl alcohol Le alcohol.

Amides and nitriles derived from the above-mentioned addition-polymerizable unsaturated carboxylic acids; aliphatic monoolefins such as ethylene, propylene, butene and isobutylene; vinyl chloride, vinyl bromide, vinyl iodide,
-Dichloroethylene, 1,2-dibromoethylene, 1,
Halogenated aliphatic olefins such as 2-diiodoethylene, isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride and vinylidene fluoride; 1,3-butadiene, 1,3- Pentadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-hexadiene 3
And conjugated diene-based aliphatic diolefins such as -methyl-2,4-hexadiene.

Further, there may be mentioned nitrogen-containing vinyl compounds such as vinyl acetates and vinyl ethers; vinyl carbazole, vinyl pyridine and vinyl pyrrolidone.

As the resin used in the present invention, one obtained by polymerizing one or more of these monomers can be used.

The transparent toner preferably contains inorganic fine particles in order to impart a suitable fluidity.
In particular, inorganic fine particles having a particle size of 0.01 μm or more and 0.1 μm or less are preferable.

Examples of the inorganic fine particles include conventionally known silica particles having a hydrophobic surface. This includes a composite metal oxide in which silica is doped with another metal, and fine particles coated with another metal or metal oxide.
In addition to silica, titanium oxide, aluminum oxide, and silicon carbide are particularly preferably particles whose surfaces are hydrophobized. Examples of the surface treatment agent include compounds containing siloxane and silicon halide. , A compound containing an alkoxysilane, a silylating agent such as silazane,
Any hydrophobized fine particles using a silylating agent such as silicone oil or a surface adsorbent can be used. Specifically, there are silazanes represented by hexamethyldisilazane, alkylalkoxysilanes represented by methyltrimethoxysilane, isobutyltrimethoxysilane, trimethoxyfluoropropylsilane, and the like. And those surface-treated using a plurality of types can be used.

For the purpose of sufficiently controlling the triboelectrification property of the toner, a so-called polarity control agent, for example, a metal complex salt of a monoazo dye, nitrohumic acid and salts thereof, salicylic acid,
Naphthoic salts, metal complexes of dicarboxylic acids such as Co, Cr and Fe, amino compounds, quaternary ammonium compounds, organic dyes and the like can be contained.

Further, a release agent may be added as required. As a release material, low molecular weight polypropylene, low molecular weight polyethylene, carnauba wax, microcrystalline wax, jojoba wax, rice wax,
A montanic acid wax or the like can be used alone or as a mixture, but is not limited thereto. In particular, carnauba wax, montan wax,
When using a release agent selected from oxidized rice wax and Fischer-Tropsch wax, it has excellent release properties, and when using a contact type fixing such as a heat roller or a heat film,
The fixing member can be used in a wide temperature range.

However, when the additives such as the polarity control agent and the release agent are added to the transparent toner, they must be selected in consideration of the coloring of the toner. As the color toner used simultaneously with the present transparent toner, all generally known toners can be used.

As a method for producing the toner, a method generally used in the related art such as a method in which a binder resin and an additive are melt-kneaded, pulverized and classified, or a so-called suspension polymerization, dispersion polymerization, emulsion polymerization and the like. Polymerization methods can also be used. The granulation method is not limited to these known methods.

The toner of the present invention can be used in any one of a one-component developing system and a two-component developing system. In the case of a two-component developer, any known carrier can be used.

As the coating resin, a resin having low surface energy and good heat resistance can be used alone or
It is also possible to use a mixture, and for example, the following may be mentioned.

Polytetrafluoroethylene (PTFE), perfluoroalkoxy / fluororesin (PFA), ethylene tetrafluoride / propylene hexafluoride copolymer (FEP), ethylene
Ethylene tetrafluoride copolymer (ETFE), polychloroethylene trifluoride (PCTFE), vinylidene fluoride (PVD)
F), vinyl fluoride (PVF), polyimide resin, polycarbonate resin and the like.

The silicone resin includes a silicone resin containing a repeating unit represented by the following general formula.

[0060]

Embedded image

In the formula, R represents a hydrogen atom, a halogen atom, a hydroxy group, a methoxy group, a C ₁ -C ₄ lower alkyl group or a phenyl group.

As straight silicone resin, KR
271, KR272, KR282, KR252, KR2
55, KR152 (manufactured by Shin-Etsu Chemical Co., Ltd.), SR240
And SR2406 (manufactured by Dow Corning Toray Silicone Co., Ltd.).

Examples of the modified silicone include an epoxy-modified silicone, an acrylic-modified silicone, a phenol-modified silicone, a urethane-modified silicone, a polyester-modified silicone, an alkyd-modified silicone, and the like.
ES-1001N, acrylic-modified silicone: KR-5
208, polyester modification: KR-5203, alkyd modification: KR-206, urethane modification: KR-305
(Shin-Etsu Chemical Co., Ltd.), epoxy-modified: SR21
15, alkyd modification: SR2110 (manufactured by Dow Corning Toray Silicone Co., Ltd.) and the like.

The silicone resin includes a silicone resin containing a repeating unit represented by the following general formula.

Further, dispersibility of the silicone resin and the additives,
In order to improve the compatibility, a generally known silane coupling agent can be included. X-Si (OR) n (where n is a positive number of 1 to 3) as a silane coupling agent
In the general formula, X represents various functional groups having reactivity with organic substances and inorganic substances and adsorptivity, and saturated and unsaturated hydrocarbon chains having functional groups. OR means an alkoxy group. In particular, a so-called aminosilane coupling agent having an amino group at X is preferably used.

Further, the following substances can be contained in the coat layer in order to adjust the resistance and increase the film strength. Examples include metal powders such as conductive ZnO and Al, SnO ₂ , MOB ₂ , silicon carbide, conductive polymers, carbon black, and the like prepared by various methods.

Examples of the carrier core material include ferromagnetic substances such as iron and cobalt, magnetite, hematite, Li-based ferrite, Mn-Zn-based ferrite, Cu-Zn-based ferrite, Ni-Zn ferrite, and the like.
Ba ferrite and the like.

As a method for forming the coating resin of the present invention, known methods such as a spray drying method, a dipping method, and a powder coating method can be used. Further, the present invention will be described in detail with reference to examples.

Toner Production Example 1 Binder resin A Polyol resin: (Mw: 22000, Mn: 6000 Mw) 100 parts by weight Colorant <for yellow toner> Disazo yellow pigment (CI Pigment Yellow 17) 5 parts by weight <For magenta toner> Quinacridone-based magenta pigment (CI Pigment Red 122) 4 parts by weight <For cyan toner> Copper phthalocyanine blue pigment (CI Pigment Blue 15) 2 parts by weight Charge control agent (zinc salt of salicylic acid derivative) 2 Parts by weight

After the above materials were sufficiently mixed in a blender, they were melted and kneaded by two rolls heated to 100 to 110 ° C. After naturally cooling the kneaded product, it was coarsely pulverized by a cutter mill, and then finely pulverized by a jet air stream type fine pulverizer. Further, classification was performed with an air classifier to obtain toner base particles A.

Subsequently, 0.7 parts of hydrophobic silica fine powder (manufactured by Nippon Aerosil Co., Ltd., TS530, manufactured by Cabot) was added to 100 parts of the toner base particles A, and the mixture was stirred for 5 minutes with a Henschel mixer. The powder was sieved with a mesh having an opening of 100 μm to remove coarse particles, thereby obtaining toners Y, M, and C. When the volume average particle diameter of each toner was measured with Coulter Multisizer II manufactured by Coulter Co., Ltd., toner Y yellow: 7.6 μm toner M magenta: 7.4 μm toner C cyan: 7.7 μm It measured with the RheoStress RS50 stress control type viscoelasticity measuring device made by HSSKE.

G 'at 140 ° C. of these toners is 780
00 dyne / cm ² was as follows. Toner Y Yellow: 7.6 μm Toner M Magenta: 7.4 μm Toner C Cyan: 7.7 μm

Toner Production Example 2 50 parts by weight of binder resin A (polyester resin: Mw: 18000, Mn: 4300 Mw / Mn: 4.19) Binder resin B (polyol resin: Mw: 18000, Mn: 4300 Mw / Mn) : 5.56) 50 parts by weight Charge control agent (salicylic acid derivative zinc salt) 2 parts by weight

Except that the materials used are as described above,
A toner CL1 was obtained in the same manner as in Production Example 1. G ′ of this toner at 140 ° C. was 54000 dyne / cm ² .

Toner Production Example 3 50 parts by weight of binder resin A (polyester resin: Mw: 30,000, Mn: 10,000 Mw / Mn: 3.00) Binder resin B (polyol resin: Mw: 62000, Mn: 9000 Mw / Mn) : 6.89) 50 parts by weight Charge control agent (salicylic acid derivative zinc salt) 2 parts by weight

Except that the materials used are as described above,
A toner CL2 was obtained in the same manner as in Production Example 1. G ′ of this toner at 140 ° C. was 54000 dyne / cm ² .

Production Example 4 of Toner Binder Resin A (Polyester resin: Mw: 32000, Mn: 2500 Mw / Mn: 12.8) 100 parts by weight Charge control agent (salicylic acid derivative zinc salt) 2 parts by weight

Except that the materials used are as described above,
A toner CL3 was obtained in the same manner as in Production Example 1. G ′ of this toner at 140 ° C. was 62000 dyne / cm ² .

Production Example 5 of Toner Binder Resin A (polyol resin: Mw: 20,000, Mn: 6000 Mw / Mn: 3.33) 100 parts by weight Charge control agent (salicylic acid derivative zinc salt) 2 parts by weight

Except that the materials used are as described above,
A toner CL4 was obtained in the same manner as in Production Example 1. G ′ of this toner at 140 ° C. was 76000 dyne / cm ² .

Production Example 6 of Toner Binder resin A (polyol resin: Mw: 78000, Mn: 5500 Mw / Mn: 14.2) 100 parts by weight Charge control agent (salicylic acid derivative zinc salt) 2 parts by weight

Except that the materials used are as described above,
A toner CL5 was obtained in the same manner as in Production Example 1. G 'of this toner at 140 ° C. was 185,000 dyne / cm ² .

Production Example of Developer 5 parts by weight of each toner was mixed with 95 parts of a silicone-coated ferrite carrier (particle diameter: 50 μm, saturation magnetic moment at 1000 Oe: 65 emu / g) by a ball mill for 10 minutes, and then 5% by weight. A developer was prepared. All developers had a charge amount within 25 ± 2 μc / g.

Example 1 Next, using a Preter600 (a full-color digital copying machine manufactured by Ricoh), images were displayed. As the developer, Y, M, and C prepared in the production example of the developer were used. A developer using CL1 toner was used instead of BK. An inverted image of the colors M and C was output from the BK developing machine.

The image evaluation was performed as follows. Color Reproducibility A secondary color image composed of three colors of Y, M, and C was output as a chart, and the color reproducibility was evaluated. ◎ Excellent ○ Excellent △ Normal (acceptable range) × Poor

Granularity In two colors of cyan and magenta, an independent dot image of 600 dpi and 200 lpi is formed as a 3 cm square image 5 having image area ratios of 0%, 25%, 50%, 75% and 100%. Species imaged.

The fineness of the image of each area ratio was visually evaluated. 非常 Excellent. 優 れ Excellent. △ Normal (acceptable range) × Poor.

Gradation The visual evaluation was performed using the same image as the evaluation of the granularity. ◎ Excellent ○ Excellent △ Normal (acceptable range) × Poor

Gloss Uniformity Using the same image as in the evaluation of granularity, the gloss of the image portion of each density was measured with Gloss Meter VGS-1D manufactured by Nippon Denshoku Industries. The absolute value of the difference between the maximum value and the minimum value is △ K (Cya
n), ΔK (Magenta). △ K (Cyan), △ K (Mag
enta) is less than 10% ◎ 10% or more and less than 20% ○ 20% or more and less than 30% △ 30% or more ×. Δ or more was judged to be practical. Table 1 shows the evaluation results.
Shown in

Examples 2 to 4 Evaluations were made in the same manner as in Example 1 except that the developer using toner CL2 to CL4 was used instead of the developer using CL1 toner. The evaluation results are shown in Table 1.

Comparative Example 1 Evaluation was performed in the same manner as in Example 1 except that the developer using the toner CL3 was used instead of the developer using the CL5 toner. The unevenness in image gloss becomes noticeable,
In addition, many cloudy image defects were found at the boundary between the low density portion and the high density portion. The evaluation results are shown in Table 1.

[0092]

[Table 1]

[0093]

As described above, according to the present invention, the color tone is excellent, there is no roughness in the low density portion, and the gradation is excellent.
Further, it is possible to provide a toner capable of obtaining a high-quality image with little difference in glossiness due to image density.

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[Procedure amendment]

[Submission date] January 27, 2000 (2000.1.2
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0072

[Correction method] Change

[Correction contents]

The storage elastic modulus of these toners at 140 ° C. was 78,000 dyne / cm ² .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Matsuda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Hiroto Higuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Aiko Ishikawa 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H005 AA01 AA06 AA08 CA07 CA08 CA15 CB13 DA04 EA07 EA10 2H077 EA03 EA11 GA13

Claims (6)

[Claims] 1. A transparent toner used in a color image forming method using Y, M, C, and BK, and further, a storage elastic modulus G obtained by measuring dynamic viscoelasticity at 140 ° C. of the toner. '1 is another, Y, M,
A toner for developing an electrostatic latent image, wherein the toner has a storage modulus of less than G'2 of any one of C and BK. 2. The method according to claim 1, wherein when the reflection density I1 of the fixed image formed on the transfer paper having an adhesion amount of 0.1 mg / cm ² , the reflection density I2 of the transfer paper, and ΔI = | I1-I2 | Is 0.
A toner for developing a substantially transparent electrostatic latent image, wherein the toner is 1 or less. 3. The method according to claim 1, wherein the glossiness K1 of the fixed image formed on the transfer paper having the adhesion amount of 0.1 mg / cm ² , the glossiness K2 of the other color toners, and ΔK = | K1-K2 | , ΔK is less than 20%, a substantially colorless and transparent electrostatic latent image developing toner. 4. The toner for developing an electrostatic latent image according to claim 1, wherein the transparent toner contains 60% by weight or more of a polyester resin. 5. The toner for developing an electrostatic latent image according to claim 1, wherein the transparent toner contains at least 60% by weight of a polyol resin. 6. The toner for developing an electrostatic latent image according to claim 1, wherein the transparent toner contains at least 0.01 μm or more and 0.1 μm or less of inorganic fine particles.