JPS5842462B2 - Color Density Shiny Toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer using a negatively charged yellow toner for use in color electrophotography.

Conventionally, various electrophotographic methods have been described in U.S. Pat. An electrical latent image is formed on a photoreceptor by the means described above, and then the latent image is developed with toner, and if necessary, the powder image is transferred to paper or the like and then fixed by heating or solvent vapor.

To obtain a multicolor image, the original is exposed using a color separation filter, and the above process is repeated multiple times using yellow, magenta, cyan, and other color toners to create a color image by superimposing the toner images. .

Furthermore, toner for developing electrical latent images has conventionally been made by finely pulverizing particles of approximately 1 to 20 μm in size, with colorants (carbon black, dyes and pigments, etc.) dispersed in a binder resin such as polystyrene. It was used as a toner.

Such toners are usually mixed with a carrier material such as glass beads, iron powder, or fur and used to develop the electrical latent image.

However, color electrophotographic toners require various conditions as described below.

(1) Toner needs to be highly transparent in order to layer multiple colors.

(2) It is necessary to selectively impart positive or negative charge to the toner.

(3) The image must be stable to heat and light and have excellent bleedability.

(4) Toner with good spectral reflection characteristics is required to faithfully reproduce the original.

It is quite difficult to simultaneously satisfy the various conditions mentioned above.

In particular, it is often difficult to obtain a yellow toner that exhibits negative chargeability and has good spectral reflection characteristics.

That is, in order to obtain conventionally negatively charged toner, Japanese Patent Publication No. 41-2
No. 0153, No. 43-27596, No. 44-6397
It was produced by mixing metal-containing dyes (red-black, blue-black) described in No. 2003 and No. 45-26478 with a binder resin. However, when a yellow toner contains a metal-containing dye, the color deteriorates and it is not preferable to obtain a pure yellow toner.

The present inventors investigated combinations of various yellow dyes and pigments with a large number of binder resins, and as a result, developed a negatively charged yellow toner that fully satisfies the above conditions.

The present invention provides a developer using a yellow toner having excellent light transmittance and excellent spectral characteristics for use in reproducing yellow images in color electrophotography.

Furthermore, the present invention provides a developer using a negatively charged yellow toner having excellent heat resistance and light resistance for use in color electrophotography.

That is, the present invention provides a diol component selected from glycols and bisphenol diols, and a dicarboxylic acid component selected from phthalic acid, inphthalic acid, terephthalic acid, aliphatic dicarboxylic acids having 2 to 8 carbon atoms, and acid anhydrides thereof. A color electronic device characterized in that a toner containing 3 to 15 parts by weight of a benzidine-based yellow organic pigment and carrier iron powder are mixed with 10 parts by weight of a polyester resin having a softening point of 80 to 150° C. Found in photographic developer.

Specific examples of diol components used in the present invention include ethylene glycol, triethylene glycol, 1.2
-Propylene glycol, ■・3-propylene glycol, ■・4-butanediol, neopentyl glycol, ■・4-butynediol, bisphenol A1 hydrogenated bisphenol A1 polyoxylenated bisphenol A are used, but propylene glycol, Neopentyl glycol, bisphenol A and the like are preferred.

Examples of dicarboxylic acid components include maninic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid,
Succinic acid, adipic acid, cepatic acid, or acid anhydrides thereof are used.

The following are typical examples of the polyester resin used in the present invention, and are particularly preferred for the present invention.

Next, the benzidine-based yellow organic pigment used in the present invention is a 3,3'-dichlorobenzidine derivative, and the color index is C, 1,21090 (Pigment Yellow 12, Shimura First Yellow GF). C61
, 21095 (Pigment Yellow 14, Benzidine Yellow G, Benzidine Yellow 1.G, Palcan Fast Yellow.

Benzidine Yellow OT, Shimura First Yellow 5
GF), C01,21100 (Pigment Yellow 1
3. Benzidine Yellow GR, Permanent Yellow GR
, Shimu Rough First Yellow GR3F), etc.

These dyes have excellent transparency, colorability, light resistance, and heat resistance, and are optimal as pigments for yellow toners.

Therefore, using the above-mentioned polyester resin and yellow pigment, a thickness of about 1 to 30 μm is obtained by a conventionally known method.

If a toner is produced by finely pulverizing the toner, a negatively charged toner that has excellent translucency and spectral properties, is light and heat resistant, and will not fade can be obtained.

These toners are mixed with iron powder to form a dry electrophotographic developer.

The present invention will be specifically explained below using examples.

Examples 1 to 16 The combination of polyester resin and benzidine-based yellow organic pigment shown in the table below was mixed and pulverized in a ball mill, thoroughly melted and kneaded in a roll mill at about 140°C, cooled, and coarsely pulverized using a hammer mill. Finely pulverize using an air jet type pulverizer.

(Crushing pressure 5-6 kg/c1rL, supply amount 310 kg/
hr) The obtained fine powder is classified and 5 to 30 microns are selected and used as toner.

The color purity of the toner is shown in the table below.

To 20 parts of this toner, 80 parts of carrier iron powder (manufactured by Nippon Steel Powder, trade name: EF300-50o) was mixed to prepare a developer.

The amount of toner tribo at this time is shown in the table below.

Using this developer, a dry plain paper electrophotographic copying machine (product name N)
When images were printed using PI100 (manufactured by Canon), clear yellow images were obtained in all cases.

Furthermore, for comparison, the color purity and tribo amount of toners using various other resins or various other yellow pigments are shown in the table below.

Comparative Examples 1 to 11 were carried out in exactly the same manner as in the above Examples except for the binding process.

Comparative Examples 12 to 14 were carried out in the same manner as in the above Examples except for the pigment.

However, the color purity was measured using a color difference meter (manufactured by Nippon Juishiki).

Further, the amount of triboelectric acid (μc/2) was measured as follows.

■ Add a small amount of toner to carrier iron powder (EF100-150).
mesh) to form a developer, put it into a measuring device, and place the device flat on a balance.

2. Next, connect this device to a V meter (TR865 manufactured by Takeda Buken)
1), and then remove the toner in the developer using a cleaner from the bottom of the measuring device.

At this time, the needle of the V meter is oscillating (so stop it at an arbitrary scale, remove the device from the meter, and measure the amount of developer remaining with a balance.

Dividing the previously read V by the decreased toner amount W(y) yields 2 V.

The value obtained by subtracting the capacitance C (μF) of the measuring device from this value is the triboelectric charge amount of the toner.

Toner triboelectric charge (μc/f) -

Claims (1)

[Claims] 1 Synthesized from a diol component selected from glycols and bisphenol diols and a dicarboxylic acid component selected from phthalic acid, isophthalic acid, terephthalic acid, aliphatic dicarboxylic acids having 2 to 8 carbon atoms, and acid anhydrides thereof. Polyester resin 100 with a softening point of 80 to 150°C
A developer for color electrophotography, characterized in that a toner containing 3 to 15 parts by weight of a benzidine-based yellow organic pigment and carrier iron powder are mixed.