JP3204500B2 - Full color toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color toner used for developing an electrostatic latent image formed in electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art Various image forming methods such as a multi-transfer method and a multi-developing method are known. In particular, toner images of respective colors are sequentially transferred to an intermediate transfer member and then collectively transferred onto a transfer material. The intermediate transfer body system that forms an image by transferring is
Since the transfer mechanism has a relatively small volume and the size of the apparatus is easily reduced, it is relatively frequently used as a desktop-size full-color laser printer or the like. But,
As described above, since the number of transfers is large in this intermediate transfer member system, the transfer image is delicately moved in a conventional toner to which inorganic fine particles having an average particle diameter of 8 to 16 nm are added as a fluidity improver, and especially, printing durability. The change in hue at the time becomes large.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a full-color toner having a small change in hue even when subjected to continuous printing by an electrophotographic apparatus of an intermediate transfer system.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a full-color electrophotographic apparatus used in an intermediate transfer body type electrophotographic apparatus in which toner images of respective colors are sequentially transferred to an intermediate transfer body and then collectively transferred to a transfer material to form an image. In the toner, an average particle diameter of 20 to 3 is applied to the surface of fine resin particles containing a binder resin and a colorant.
50 nm inorganic fine particles and particles having an average particle size of less than 20 nm.
The present invention relates to a full-color toner to which Rica is externally added.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The binder resin used in the present invention is:
Polyester, styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane and the like are mentioned, and polyester is preferred from the viewpoint of dispersibility, fixability and chargeability of the colorant.

The raw material monomers for the polyester are not particularly limited, and include known polyhydric alcohol components and polyvalent carboxylic acid components such as carboxylic acids, carboxylic anhydrides, and carboxylic esters.

The polyhydric alcohol components include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.0)-
Bisphenol A alkylene (C2-3) oxide (average number of moles added 1-10) adduct of bisphenol A such as 2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, propylene glycol, glycerin, pentaerythritol, tri Methylolpropane, hydrogenated bisphenol A, sorbitol, or their alkylene (C2-3) oxides (average addition moles 1-1)
0) adducts and the like; those containing one or more of these are preferred. Further, from the viewpoint of improving the durability of the toner, alkylene of bisphenol A (having 2 to 2 carbon atoms)
3) It is desirable that the oxide adduct is used in an alcohol component in an amount of 5 mol% or more, preferably 50 mol% or more.

The polyvalent carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, and maleic acid; alkyl groups having 1 to 20 carbon atoms such as dodecenylsuccinic acid and octylsuccinic acid; Number 2
Succinic acid, trimellitic acid, pyromellitic acid, anhydrides of these acids and alkyl (C1-8) esters of these acids, etc., substituted with an alkenyl group of from 20 to 20; Is preferred.

The polyester may be prepared, for example, by mixing a polyhydric alcohol component and a polycarboxylic acid component in an inert gas atmosphere, using an esterification catalyst, if necessary, for 180-250.
It can be produced by condensation polymerization at a temperature of ° C.

The acid value of the polyester is from 1 to 25 mg KOH.
/ G, a hydroxyl value of 20 to 60 mgKOH / g, a softening point of 90 to 140 ° C, and a glass transition point of 50 to 70 ° C.

As the colorant, all dyes and pigments used as colorants for toner can be used. Carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine- B base, Pigment Red 17, Pigment Red 57: 1, Solvent Red 49, Solvent Red 146, Pigment Blue 15: 3, Solvent Blue 35, Carmine 6
B, Pigment Yellow 17, Disazo Yellow and the like, and these can be used alone or in combination of two or more. The content of the colorant is preferably 1 to 10 parts by weight based on 100 parts by weight of the binder resin.

According to the present invention, an average particle diameter of 20 to 350 nm, preferably 25 to 50 nm is applied to the surface of resin fine particles containing the above-mentioned binder resin and colorant as an external additive.
It has a great feature in that inorganic fine particles having a large particle diameter are added. When such large-sized inorganic fine particles are externally added, the movement of the toner at the time of transfer is suppressed, and a clear image can be formed even if the transfer is performed a plurality of times.

In the present invention, further, the average particle diameter is 20 n
It is desirable that inorganic fine particles having a small particle diameter of less than m, preferably 8 nm or more, less than 20 nm, more preferably 10 to 18 nm are externally added to the surface of the resin fine particles. When the inorganic fine particles having such a small particle diameter are used in combination with the inorganic fine particles having a large particle diameter as described above, for example, when the toner of the present invention is used in a non-magnetic one-component developing system, charge control is easily performed. In addition to the above, a suitable fluidity is generated, and it can be used for a developing roll having a smoother surface, so that the durability can be further improved. The mixing ratio of the two types of inorganic fine particles is (inorganic fine particles having a large particle diameter) / (inorganic fine particles having a small particle diameter) (weight ratio), and is preferably 80/20 to 20/80, and 80/2.
0 to 50/50 is more preferable. The particle size of the inorganic fine particles can be determined using a scanning electron microscope or a transmission electron microscope.

The inorganic fine particles used in the toner of the present invention include silicon dioxide (silica), titanium dioxide, aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide and the like. Among them, from the viewpoint of imparting chargeability, silica and titanium dioxide are preferable, and silica is more preferable. In addition, the inorganic fine particles can be used alone or in combination of two or more. In the present invention, at least one of the inorganic fine particles used as the external additive is subjected to hydrophobic treatment with silicone oil. preferable.

The method of hydrophobizing treatment with silicone oil is not particularly limited as long as the silicone oil is adsorbed on the surface of the inorganic fine particles. For example, the silicone oil is diluted with a solvent while stirring the inorganic fine particles in a mixing tank. And drying by heating in a tank for a certain period of time while continuing stirring.

In the present invention, the amount of silicone oil added to the inorganic fine particles in the hydrophobizing treatment is preferably 2-3 mg / m ² per surface area of the inorganic fine particles. 2 added
The effect of reducing fog is increased at mg / m ² or more, and the aggregation of inorganic fine particles is prevented at 3 mg / m ² or less,
The inorganic fine particles can be uniformly attached to the surfaces of the resin fine particles. Such an addition amount is such that the BET specific surface area is 50
In the case of m ² / g inorganic fine particles, it corresponds to 10 to 15 parts by weight per 100 parts by weight of the inorganic fine particles.

In the present invention, as a commercially available product used as large-diameter inorganic fine particles, "NAX-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, average particle size: 35 n)
m), "EC-300" (titanium dioxide, average particle size: 320 nm, manufactured by Titanium Industry Co., Ltd.), and commercially available products used as inorganic fine particles having a small particle size include "R-97".
2 "(manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, average particle size: 16 nm)," R-974 "(manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, average particle size: 12 nm) and the like.

The content of the external additive is preferably 0.1 to 5.0 parts by weight, and more preferably 0.3 to 5.0 parts by weight based on 100 parts by weight of the resin fine particles.
3.0 parts by weight is more preferred.

Further, in the present invention, it is preferable that wax is contained in the resin fine particles. Examples of the wax include natural waxes such as carnauba wax and rice wax, synthetic waxes such as polypropylene wax, polyethylene wax and sasol wax, coal-based waxes such as montan wax, alcohol-based waxes, ester-based waxes, and the like. Among them, carnauba wax is preferred from the viewpoint of compatibility with the binder resin. The content of the wax is preferably 1 to 10 parts by weight, more preferably 2 to 5 parts by weight, based on 100 parts by weight of the binder resin.

The toner of the present invention is not particularly limited, and examples thereof include a pulverized toner, a polymerized toner, and a capsule toner. For example, resin fine particles obtained by a known method such as a kneading and pulverizing method, a spray drying method, and a polymerization method To which an external additive is added. As a general method, for example, a binder resin,
After uniformly mixing the colorant etc. with a mixer such as a ball mill,
The mixture is melt-kneaded in a closed kneader or a single-screw or twin-screw extruder, cooled, pulverized and classified to obtain fine resin particles. Thereafter, the obtained resin fine particles and the external additive are stirred and mixed by a high-speed stirrer such as a super mixer or a Henschel mixer, so that the external additive is attached to the surface of the resin fine particles to obtain the toner of the present invention. . The weight average particle diameter of the toner of the present invention is preferably 3 to 10 μm.

The toner of the present invention has a charge control agent,
Conductive filler, extender, reinforcing fillers such as fibrous substances,
Additives such as an antioxidant, an antioxidant, and a cleaning property improver may be appropriately added.

The full-color toner of the present invention is used as a non-magnetic one-component developer when no magnetic fine powder is contained, or as a two-component developer by mixing with a carrier. It is preferably used as a non-magnetic one-component developer because of its easiness.

The full-color toner of the present invention is used in an electrophotographic apparatus of an intermediate transfer body type in which toner images of each color are sequentially transferred to an intermediate transfer body and then collectively transferred to a transfer material to form an image. As an electrophotographic apparatus of the intermediate transfer body type, for example, as shown in FIG. 1, an apparatus having a developing unit 1, a photoreceptor 2, and an intermediate transfer body 3 in which respective developing tanks contain toners of different hues, respectively, is exemplified. The image formation by the intermediate transfer system using such an electrophotographic apparatus can be performed, for example, according to the following principle.

(1) The surface of the photoconductor 2 is charged by the charging device 4, and an electrostatic latent image having a desired image pattern is formed on the photoconductor 2 by the exposure device 5. (2) The toner in the first developing tank 6 is caused to adhere to the electrostatic latent image by the developing roll 7. (3) The toner image developed on the photoconductor 2 is transferred to the primary transfer device 8
To transfer to the intermediate transfer member 3. (4) The first developing tank 6 is sequentially changed to the second developing tank 9 to the fourth developing tank 11, and the steps (1) to (3) are repeated. (5) The toner images of a plurality of colors formed on the intermediate transfer member 3 are collectively transferred to the transfer material by the secondary transfer device 12 and then fixed by the fixing device 13.

The present invention is not particularly limited as long as it is an electrophotographic apparatus of an intermediate transfer body type utilizing the above-described principle.
No. 5113, etc., a driving device that stretches a photosensitive belt long in an oblique direction with respect to gravity and drives the moving direction of the photosensitive belt upward from below in the direction of gravity; Various electrophotographic apparatuses such as a color electrophotographic apparatus in which a plurality of developing devices are stacked on one side of a body belt can be used.

The center line surface roughness (Ra) of the developing roll of the electrophotographic apparatus using the toner of the present invention is described.
Is preferably 0.20 to 0.50 μm, more preferably 0.25 to 0.42 μm, from the viewpoint of high image quality. In the present invention, the center line surface roughness (Ra) of the developing roll is:
It can be measured by the method described in JIS B0601.

The full-color toner of the present invention can be used as a two-component developer by mixing with a carrier. However, since the toner itself has excellent chargeability, it is particularly suitable for a non-magnetic one-component developing device. Can be used.

[0028]

[Example] [Glass transition point] Differential scanning calorimeter "DSC2"
10 "(manufactured by Seiko Denshi Kogyo KK) at a heating rate of 10 ° C / min.

[Acid value and hydroxyl value] JIS K0070
It measures by the method of.

Resin Production Example 1 Polyoxypropylene (2.2) -2,2- (4-hydroxyphenyl) propane 12250 g, polyoxyethylene (2.0) -2,2- (4-hydroxyphenyl) propane 21125 g , 14940 g of terephthalic acid
And 15 g of dibutyltin oxide in a nitrogen atmosphere at 230 ° C.
The resin A was obtained by reacting with stirring under vacuum until the softening point measured by ASTM E28-67 reached 121 ° C. Resin A has a glass transition point of 66 ° C. and an acid value of 3.
44 mgKOH / g, hydroxyl value is 23.4 mgKOH / g
g.

Example 1 (a) Production Example of Cyan Toner 93.0 parts by weight of resin A as binder resin and 3.5 parts by weight of Pigment Blue 15: 3 “ECB-301” (manufactured by Dainichi Seika) as a colorant Part, LR-14 as a charge control agent
7 "(manufactured by Nippon Carlit Co., Ltd.) and 1.5 parts by weight of polypropylene wax" Mitsui High Wax NP
-105 "(manufactured by Mitsui Chemicals, Inc.) was mixed using a Henschel mixer, and then melt-kneaded with a twin-screw extruder, and a collision-type pulverizer" Dispersion Separator "(Nippon Pneumatic Industries, Ltd.) And pulverization and classification were performed to obtain a powder having a weight average particle size of 8.5 μm and a variation coefficient of 25.1%.

100 parts by weight of the obtained powder was mixed with hydrophobic silica “NAX-50” (manufactured by Nippon Aerosil Co., Ltd., average particle size:
(35 nm) 2.5 parts by weight, and stirred with a 10-liter Henschel mixer at 3200 r / min for 180 seconds to obtain a cyan toner.

(B) Production Example of Magenta Toner The amount of resin A used was changed to 91.5 parts by weight, and instead of Pigment Blue 15: 3, Pigment Red 57:
1 A powder having a weight average particle size of 8.5 μm and a coefficient of variation of 25.6% in the same manner as in the production example of the cyan toner, except that 5.5 parts by weight of “ECR-101” (manufactured by Dainichi Seika) was used. After the body was obtained, it was mixed with hydrophobic silica to obtain a magenta toner.

(C) Production Example of Yellow Toner The amount of Resin A used was changed to 93.5 parts by weight, and instead of Pigment Blue 15: 3, Pigment Yellow 17 was used.
A powder having a weight average particle size of 8.5 μm and a coefficient of variation of 26.0% in the same manner as in the production example of the cyan toner, except that 3.5 parts by weight of “ECY-215” (manufactured by Dainichi Seika) was used. Was mixed with hydrophobic silica to obtain a yellow toner.

Example 2 As hydrophobic silica, instead of 2.5 parts by weight of “NAX-50”, 1.2 parts by weight of “NAX-50” and “R-97” were used.
2 "(manufactured by Nippon Aerosil Co., Ltd., average particle size: 16 nm)
Except that 0.5 part by weight was used, the same as in Example 1,
A cyan toner, a magenta toner, and a yellow toner were obtained.

Example 3 Instead of 2.5 parts by weight of hydrophobic silica “NAX-50”, 1.0 part by weight of conductive titanium dioxide “EC-300” (manufactured by Titanium Co., Ltd., average particle size: 320 nm) was used. A cyan toner, a magenta toner and a yellow toner were prepared in the same manner as in Example 1 except that 0.5 parts by weight of hydrophobic silica “R-974” (manufactured by Nippon Aerosil Co., Ltd., average particle size: 12 nm) was used. Got each.

Example 4 (a) Production Example of Cyan Toner The amount of resin A used was changed to 92.5 parts by weight, and instead of polypropylene wax, carnauba wax "Carnauba wax No. 1" (imported by Kato Yoko Co., Ltd.) ) A powder having a weight average particle size of 8.5 μm and a coefficient of variation of 25.2% was obtained in the same manner as in Example 2 except that 2.5 parts by weight was used, and then mixed with hydrophobic silica. A cyan toner was obtained.

(B) Production Example of Magenta Toner The amount of resin A used was changed to 90.5 parts by weight, and instead of Pigment Blue 15: 3, Pigment Red 57:
1 Powder having a weight average particle size of 8.6 μm and a coefficient of variation of 25.7% was prepared in the same manner as in the production example of the cyan toner, except that 5.5 parts by weight of “ECR-101” (manufactured by Dainichi Seika) was used. After the body was obtained, it was mixed with hydrophobic silica to obtain a magenta toner.

(C) Production Example of Yellow Toner Pigment Yellow 17 "ECY-215" (manufactured by Dainichi Seika) instead of Pigment Blue 15: 3 3.5
A weight average particle diameter of 8.5 μm and a variation coefficient of 26.0% were performed in the same manner as in the production example of the cyan toner except that the parts by weight were used.
Was obtained and mixed with hydrophobic silica to obtain a yellow toner.

Comparative Example 1 As hydrophobic silica, 0.6 parts by weight of “R-972” (manufactured by Nippon Aerosil Co., Ltd., average particle diameter: 16 nm) was used instead of 2.5 parts by weight of “NAX-50”. A cyan toner, a magenta toner, and a yellow toner were obtained in the same manner as in Example 1 except for the above.

Test Example 1 The cyan toner, magenta toner and yellow toner obtained in Examples 1 to 4 and Comparative Example 1 were referred to as “IPSIO C
OLOR 2000 "(manufactured by Ricoh Co., Ltd.), and using a plain paper" XEROX4200 ", the printing ratio per sheet of cyan toner, magenta toner and cyan toner is 5
% Printing was continuously performed on 3000 sheets, and the degree of hue change was evaluated. The center line surface roughness (Ra) of the developing roll of the apparatus is 0.25 μm, and the hue change is “SP”.
Using ECTRODENSITOMETER 938 (manufactured by X-rite), the difference (ΔE) in the change in hue between the first and 3,000 sheets was measured and evaluated according to the following evaluation criteria. Further, the developing roll was adjusted to have a center line surface roughness (Ra) of 0.42 μm,
Continuous printing was performed in the same manner by replacing the developing roll with 0.55 μm, and the degree of hue change was evaluated. Table 1 shows the results.

Note that "IPSIO COLOR 200
“0” is a non-magnetic one-component developing device of an intermediate transfer body type in which a photosensitive belt and a plurality of developing devices of different colors are arranged around the photosensitive belt.

Test Example 2 Continuous printing was performed in the same manner as in Test Example 1 except that the cyan toner, magenta toner and yellow toner obtained in Example 2 were mounted on “Page Presto N-4” (manufactured by Casio Computer Co., Ltd.). And the degree of hue change after printing the first and 3,000 sheets was evaluated according to the following evaluation criteria. Table 1 shows the results
Shown in

"Page Presto N-4" is 4 pages.
This is a tandem type non-magnetic one-component developing device that develops using the photoreceptor of the present invention.

[Evaluation Criteria] A: ΔE is less than 2.0, which is particularly good for practical use. ：: ΔE is 2.0 or more and less than 5.0, and there is no problem in practical use. Δ: ΔE is not less than 5.0 and less than 10.0, and can be actually used. C: ΔE is 10.0 or more and cannot be used.

[0046]

[Table 1]

According to the results of Test Example 1, the toner of Comparative Example 1 in which only the inorganic fine particles having a small particle diameter was added as an external additive showed a very large change in hue, whereas the toners of Examples 1 to 4 showed an intermediate change. It can be seen that the image obtained by mounting on the transfer body type device has a small change in hue, and in particular, the toner of Example 4 in which carnauba wax was blended, provided an excellent image. Further, from the results of Test Example 2, it can be seen that the toner capable of obtaining a good image with the intermediate transfer body type device has a very large hue change with the tandem type device and cannot be used.

[0048]

According to the present invention, it has become possible to provide a full-color toner having a small change in hue even when subjected to continuous printing by an intermediate transfer type electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of an electrophotographic apparatus of an intermediate transfer body type using a toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Photoreceptor 3 Intermediate transfer member 4 Charging device 5 Exposure device 6 First developing tank 7 Developing roll 8 Primary transfer device 9 Second developing tank 10 Third developing tank 11 Fourth developing tank 12 Secondary transfer device 13 Fuser

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidenori Tate 1334 Minato, Wakayama-shi Kao Corporation Laboratory (56) References JP-A-11-212364 (JP, A) JP-A 10-207245 (JP, A) JP-A-11-184239 (JP, A) JP-A-8-15979 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/01, 9/08

Claims (5)

(57) [Claims] 1. A full-color toner used in an electrophotographic apparatus of an intermediate transfer body type in which a toner image of each color is sequentially transferred to an intermediate transfer body and collectively transferred to a transfer material to form an image. A full-color toner in which inorganic fine particles having an average particle diameter of 20 to 350 nm and silica having an average particle diameter of less than 20 nm are externally added to the surface of resin fine particles containing an agent. 2. The full-color toner according to claim 1, wherein the wax is contained in the resin fine particles. 3. The full-color toner according to claim 1, wherein the center line surface roughness of the developing roll of the electrophotographic apparatus is 0.20 to 0.50 μm. 4. The full-color toner according to claim 1, wherein the electrophotographic device is a non-magnetic one-component developing device, and the binder resin is polyester. 5. Inorganic fine particles having an average particle diameter of 20 to 350 nm
The full color according to any one of claims 1 to 4, wherein the particles are silica.
-Toner.