JPH04174865A - Color toner for electrophotography - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding electrophotographic color toner used for developing electrostatic latent images such as electrophotography, we have developed an electrophotographic color toner that has excellent color mixing properties and transparency without impairing other properties. The purpose is to provide photographic color toners, which contain organic pigments, phthalic acid, isophthalic acid, terephthalic acid,
A line obtained by reacting a diisocyanate with a linear polyester resin consisting of a dicarboxylic acid selected from aliphatic dicarboxylic acids having 2 to 8 carbon atoms and their acid anhydrides, and a diol selected from glycols and bisphenol type diols. The linear urethane-modified polyester resin contains the organic pigment in an amount of 2 to 10 W[%] based on the linear urethane-modified polyester resin.

[Industrial Application Field] The present invention relates to a color toner for electrophotography used for developing electrostatic latent images in electrophotography and the like.

As an electrophotographic method, the method described in US Pat. No. 2,297,691 and the like is well known. This generally involves using a photoconductive insulator (such as a photocondrum), applying a -like electrostatic charge on the photoconductive insulator by corona discharge, etc., and applying various means to the photoconductive insulator. An electrostatic latent image is formed by irradiating the image with a light image, and then the latent image is developed and visualized using fine powder called toner. After transferring the toner image to paper etc. as necessary, pressure is applied. A copy is obtained by fixing a toner image on a recording medium such as paper by means such as heating, irradiation with a solvent, steam, or light.

[Prior Art and Problems to be Solved by the Invention] The developer may be a two-component developer consisting of a magnetic carrier and a non-magnetic or magnetic toner, or a one-component developer consisting of a magnetic or non-magnetic toner. Among these, two-component developers charge the toner due to friction between the carrier and toner, so as the number of prints increases, the toner adheres to the magnetic carrier surface, deteriorating the carrier and extending the lifespan of the developer. But it has shortcomings. On the other hand, a one-component developer does not use carrier and only consumes toner, so the carrier does not deteriorate, so it has the advantage of having a long life as a developer. However, when a magnetic toner is used as a one-component developer, it is difficult to produce color because it is necessary to contain magnetic powder (black).

Furthermore, when a non-magnetic toner is used, the toner is required to have various properties, such as ease of colorization and long developer life.

Next, a developing method will be explained using the apparatus shown in FIG.

In FIG. 1, a flexible material is provided on the surface between a storage means 2 that stores the developer 1 and a developer carrier 3 that transports the developer 1 along a predetermined circulation path including the development area. The developer collecting means 4 in the form of a roller is provided so as to be in contact with the developer carrier 3, and the developer 1 is disposed between the developer carrier 3 and the developer collecting means 4. A bias voltage (hereinafter referred to as recovery bias) is applied in the direction from the developer recovery means 3 to the developer recovery means 4, and not only mechanical recovery by contact but also electrical cancellation by the recovery bias is performed stably and reliably. Mechanical and electrical history on the developer carrier 3 is eliminated. Therefore, the developer 1 stored in the storage means 2 is newly supplied to the developer support 3 by the developer supply means 5 while being in contact with the developer support 3, and the frictional charging member 6 applies mechanical friction to the developer 1. The developer is charged, a charged toner layer is formed on the developer carrier 3, and the layer thickness is regulated to a desired thickness by a triboelectric charging member (layer thickness regulation member) 6, and then transported to a development area and developed. conduct.

Reference numeral 7 denotes a latent image carrier, which conveys the latent image formed on its surface to a developing section, and conveys the formed image of the developer 1 to a position where it is transferred onto the recording paper 14. This latent image carrier 7 has
Depending on the latent image forming method, a photoconductive material such as a photoconductor (organic photoconductor, selenium photoconductor, amorphous silicon photoconductor, etc.), an insulator, etc. can be used.

In the figure, 8 is an exposure device, 9 is a front charger, 10 is a cleaner unit, 11 is a static elimination lamp, 12 is a fixing device, 1
3 is a transfer device.

When the above development method is used, the following problems occur.

When the toner on the developer carrier 3 is strongly tribo-electrified by the tribo-electrifying member 6, it is charged with good rising characteristics, but some of the toner is finely pulverized and the average particle size of the toner becomes smaller than that for continuous printing. This causes problems such as fogging due to poor charging, poor cleaning due to selective development, decreased print density, and poor printing due to fusion of finely ground toner on the developer carrier, and print quality deteriorates significantly over long periods of continuous printing. let For this reason, the toner is required to have characteristics that make it difficult to be crushed.

The toner is a fine powder obtained by dispersing a coloring agent, a charge control agent, etc. in a binder resin made of a natural or synthetic polymeric material, and pulverized to a size of about 1 to 30 μm, and is usually made of iron powder, ferrite powder, etc. is mixed with a carrier material (carrier) to form a developer and used for the development,
The toner image is formed only with that toner.

When a multicolor image is obtained by electrophotography, it is generally achieved by using toners of three colors, yellow, magenta, and cyan, and superimposing the toner images of each color and mixing the colors.

Therefore, during fixing, characteristics unique to color toners are required so that the color mixing properties and transparency of the toners do not affect image quality.

In order to improve the color mixing properties and transparency of toner, it may be possible to lower the molecular weight, glass transition point, softening point, etc. of the binder resin and improve toner leveling properties, or conversely, improve offset resistance and storage stability. It is difficult to achieve both, as it causes deterioration.

Further, when a crosslinked structure is introduced to improve offset resistance, a problem arises in that the leveling property of the toner is poor. As described above, conventional binder resins had several properties that were incompatible.

Furthermore, the following conditions apply to the coloring agent used in the color toner.

(1) Good dispersibility in the binder resin and excellent transparency.

(2) Good spectral reflection characteristics in order to widen the color reproduction range.

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a color toner for electrophotography that has excellent color mixing properties and transparency without impairing other properties. There is.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an organic pigment, phthalic acid, isophthalic acid, terephthalic acid, aliphatic dicarboxylic acids having 2 to 8 carbon atoms, and acid anhydrides thereof. It consists of a linear urethane-modified polyester resin obtained by reacting a diisocyanate with a linear polyester resin made of a dicarboxylic acid selected from among dicarboxylic acids and a diol selected from glycols and bisphenol type diols, and the organic pigment is linearly urethane-modified. 2-10 for polyester resin
vt%.

The present invention will be explained in more detail below.

The glass transition point of the linear urethane-modified polyester resin is preferably in the range of 50 to 75°C, and temperatures below 50°C result in poor storage stability, while temperatures above 75°C result in poor fixability.

It is also preferable that the linear urethane-modified polyester resin has a number average molecular weight of 2,000 to 15,000,
If it is less than 2,000, the storage stability will be poor, and if it is more than 15,000, the fixing property will be poor, which is not preferable.

As the dicarboxylic acid component used in the present invention, for example, maleic acid, fumaric acid, mesaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, etc., or anhydrides thereof are used.

In addition, the diol components include ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, l,4-butanediol, neopentyl glycol, bispheno-11,
Examples include diethylene glycol and ethylene oxide adducts of bisphenol^.

Examples of the diisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate.

The use of the isocyanate suppresses the increase in the softening point of the resin and increases the glass transition point compared to linear polyester resins, thereby achieving both fixing performance and storage stability.

Furthermore, linear urethane-modified polyester resins have superior offset resistance compared to linear polyester resins even when they have the same molecular weight.

Next, as the benzidine organic pigment used in the present invention,
For example, color index floor C, 1, 21090 (
Pigment Yellow o-12, KE Ding Yellow 406
゜Dainippon Ink & Chemicals), C, 1,21095 (Pigment Yellow 14. KET Yellow 4
04. Dainippon Ink Chemical Industry), C, 1,211
00 (Pigment Yellow 13゜KET Yellow
405. Dainippon Ink and Chemical Industries), etc.

The present material has excellent dispersibility in a linear urethane-modified polyester resin, and also has good spectral reflection properties.

Next, as the quinacridone organic pigment used in the present invention, C, 1,73916 (Pigment Red 122. KET Red 309.
(Dainippon Ink & Chemicals).

The present material has excellent dispersibility in a linear urethane-modified polyester resin, and also has good spectral reflection properties.

Next, as the rhodamine organic pigment used in the present invention,
There is a color index of Nao C11,4516[1 (Pigment Red 81.Ult+a Rose R, manufactured by Toyo Ink).

The present material has excellent dispersibility in a linear urethane-modified polyester resin, and also has good spectral reflection properties.

Next, as the phthalocyanine organic pigment used in the present invention, Color Index Fish C, 1,74160 (Pigment Blue 15.KET Blue IO2, KET
Blue 103, KET Blue 104. K.E.
T Blue 105. KET Blue 106. K
ET Blue III, Dainippon Ink & Chemicals),
C, 1,74260v pigment green? , KET
Green 201. Dainippon Ink and Chemical Industries), etc. The material of the present application has excellent dispersibility in a linear urethane-modified polyester resin, and also has good spectral reflection properties.

In addition, as charge control agents, metal-containing dyes, fatty acid esters,
A compound having an amino group may also be added.

The toner used in the present invention can be manufactured by a conventionally known method. That is, the binder resin and the pigment, and if necessary, a wax, a charge control agent, etc. are added, and then melted and kneaded using, for example, a pressure kneader or extruder, uniformly dispersed, and then mixed using, for example, a wind classifier. , the desired toner can be obtained by classification.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 100 parts by weight of a linear polyester resin (neopentyl glycol: fumaric acid = 1:1) was dissolved in xylene as a binder resin, and then 3 parts by weight of xylylene diisocyanate was added to complete the reaction. , Kiylene was removed to obtain a linear urethane-modified polyester resin.

The glass transition temperature of the resin is 58°C, and the number average molecular weight is 6.
It was 000.

Next, a toner was experimentally produced using the linear urethane-modified polyester resin with the following composition.

Linear urethane modified polyester resin 91 parts by weight Pigment: C, 1,21090, KET Yellow 406
(Dainippon Ink Manufacturing)
5 parts by weight Charge control agent: BONTRON E84 (
Orient Chemical) 2 parts by weight Wax Viscol 550-P (Sanyo Chemical) 2
Part by Weight The above composition was mixed and stirred using a ball mill, melt-kneaded using an extruder heated to 140°C, cooled and solidified, coarsely ground using a grinder, and further finely ground using a jet mill. The obtained fine powder is classified with a wind classifier to give a size of 5 to 20
A yellow toner of μm was obtained.

Using this toner as a carrier of 5% by weight and 95% of resin-coated ferrite powder (average particle size 60 μm) as a carrier,
A printing test was conducted using a laser printer that can perform color simultaneous printing and uses a heated roll fixing device. Note that toners with different coloring agents were used for both magenta and cyan.

As a result, the printed image had excellent color mixing properties and transparency, and good transparency was confirmed in OHP printing.

Furthermore, no offset occurred at all even after printing one sheet. Further, even when the yellow toner was left at 40° C. and 80% RH for one month, no change was observed, and the storage stability was good.

Example 2 Quinacridone pigment KET Red 3 as organic pigment
Example 1 except that 09 (Dainippon Ink & Chemicals) was used.
Similarly, a magenta toner was prototyped. Next, as a result of evaluation in the same manner as in Example 1, good results were obtained as in Example 1.

Example 3 Rhodamine pigment Ultra Rose as an organic pigment
A magenta toner was prototyped in the same manner as in Example 1 except that R (manufactured by Toyo Ink) was used. Next, as a result of evaluation in the same manner as in Example 1, good results were obtained as in Example 1.

Example 4 Phthalocyanine pigment KET BLI as an organic pigment:
A cyan toner was prototyped in the same manner as in Example 1 except that Ell (Dainippon Ink & Chemicals) was used. Next, Example 1
As a result of evaluation in the same manner as in Example 1, good results were obtained as in Example 1.

Example 5 As a result of evaluation in the same manner as in Example 1 except that a developer employing a non-magnetic one-component method was used as the developer, the printing quality, filming of the triboelectric charging member, and toner were maintained even after continuous printing of 100,000 sheets. There was no change in the particle size distribution.

Example 6 As a linear polyester resin (propylene glycol:
Maleic anhydride: phthalic anhydride = 5.25:2.5.2
．． A linear urethane-modified polyester resin (glass transition temperature: 65°C,
After obtaining a number average molecular weight of 100QQ), a yellow toner was produced as a trial.

Next, as a result of evaluation in the same manner as in Example 1, good results were obtained as in Example 1.

Example 7 A linear urethane-modified polyester resin (glass transition temperature: 59°C, number average molecular weight: 8000) was obtained in the same manner as in Example 1 except that tetramethylxylylene diisocyanate was used as the diisocyanate, and then a yellow toner was produced as a prototype. did.

Next, as a result of evaluation in the same manner as in Example 1, good results were obtained as in Example 1.

Comparative Example 1 A yellow toner was obtained in the same manner as in Example 1, except that the amount of pigment added was 1 part by weight, and evaluated in the same manner as in Example 1. As a result, it was found that the density of yellow was low and the brightness was affected.

Comparative Example 2 A yellow toner was obtained in the same manner as in Example 1, except that the amount of pigment added was 15 parts by weight, and evaluated in the same manner as in Example 1. result,
It was found that the pigment concentration was too high, resulting in poor permeability.

Comparative Example 3 A yellow toner was obtained in the same manner as in Example 1, except that no diisocyanate was used, and evaluated in the same manner as in Example 1. result,
Although the color mixing properties and transparency were good, offset occurred after printing about 100 sheets, and the storage stability was also found to be poor. Furthermore, as in Example 5, an evaluation using a developing device employing a non-magnetic one-component system revealed that filming occurred on the triboelectric charging member and printing defects occurred due to insufficient charging of the toner.

Comparative Example 4 KET Blue 101 (threne-based,
Pigment Blue 60. C, I, No, 6980
0. A cyan toner was obtained in the same manner as in Example 1, except that a cyan toner (Dainippon Ink and Chemicals) was used, and evaluated in the same manner as in Example 1.

As a result, it was found that the color mixing property and transparency were poor.

Comparative Example 5 As a linear polyester resin (propylene glycol:
Maleic anhydride: phthalic anhydride = 5.25:2.5:2
．． A linear urethane-modified polyester resin (glass transition temperature: 62° C., number average molecular weight: 20,000′) was obtained in the same manner as in Example 1 except for 5), and then a yellow toner was prepared as a trial product. Next, as a result of evaluation in the same manner as in Example 1, it was found that the fixing properties were poor.

Comparative Example 6 As a linear polyester resin (propylene glycol:
A linear urethane modified polyester resin (maleic anhydride = 5.25.5) was used in the same manner as in Example 1, except that maleic anhydride = 5.25.
After obtaining a glass transition temperature of 45° C. and a number average molecular weight of +800, a yellow toner was prepared.

Next, as a result of evaluation in the same manner as in Example 1, it was found that offset occurred after about 100 sheets.

Comparative Example 7 The amount of diisocyanate added was 1/10 compared to Example 1.
A linear urethane-modified polyester resin (glass transition temperature: 45° C., number average molecular weight: 2000) was obtained in the same manner as in Example 1, except that a yellow toner was prepared as a prototype. Next, as a result of evaluation in the same manner as in Example 1, it was found that the storage stability was poor.

Comparative Example 8 Linear urethane-modified polyester resin (glass transition temperature: 80°C, number average molecular weight: +0
000), a yellow toner was prototyped. Next, as a result of evaluation in the same manner as in Example 1, it was found that the fixing properties were poor.

[Effects of the Invention] As described above, according to the present invention, a color toner having excellent color mixing properties and transparency can be obtained without impairing other properties.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an electrophotographic recording apparatus. In the figure, 1: developer, 2: Storage means, 3: developer carrier, 4: Developer recovery means, 5. Developer supply means 6: Frictional charging member, 7, latent image carrier; 8: Exposure device, 9: Front charger, 10, cleaner unit, 11: Static elimination lamp, 12: Fixing device, 13: Transfer device, 14: Recording paper.

Claims (1)

[Claims] Organic pigments, phthalic acid, isophthalic acid, terephthalic acid,
A line obtained by reacting a diisocyanate with a linear polyester resin consisting of a dicarboxylic acid selected from aliphatic dicarboxylic acids having 2 to 8 carbon atoms and their acid anhydrides, and a diol selected from glycols and bisphenol type diols. A color toner for electrophotography, comprising a linear urethane-modified polyester resin, and containing the organic pigment in an amount of 2 to 10 wt% based on the linear urethane-modified polyester resin.