JPS5993457A - Electrophotographic printing toner - Google Patents

Abstract

PURPOSE:To raise the specific amount of electrification and to improve aging stability by adding a specified dye as a negative charge controller to a toner. CONSTITUTION:The toner contains a dye represented by the formula shown here in which X is Cl, Br, SO2NH2, SO2CH3, or SO2C2H5, and A is straight or branched 8-16C alkylammonium optionally substd. by O at the intermediate C in the alkyl chain. An amt. of said charge controller to be used is 0.5-30pts.wt. per 100pts.wt. of the binder resin.

Description

[Detailed description of the invention] The present invention relates to toner for electrophotographic printing.

More specifically, it is shown in formula (1) [wherein X is C+, Br, 802NH2,5o2C
1-13,80202H5 and A has 8 to 16 carbon atoms
represents an alkyl ammonium which may be interrupted by one linear or branched oxygen atom] It relates to a toner for electrophotographic printing, characterized in that it contains a dye.

A general method of image forming process using static electricity is as follows. That is, first, the toner is charged by contact friction with glass beads, iron powder, aluminum powder, etc. called carriers, and then this is transferred onto a photoconductor made of a photoconductive substance (selenium, zinc oxide, cadmium sulfide, etc.). The electrostatic latent image is acted on to make it visible and then fixed by heating or by using a solvent or steam.

Toner usually consists of a binder resin, a charge control agent, a coloring agent, etc., and is manufactured by finely pulverizing it to a size of 1 to 50 microns.The quality characteristics required for this toner include chargeability, fluidity, and stability over time. This is a very important property for image formation.

Among the charge control agents used in toners, nigrosine dyes, quaternary ammonium salts, and pyridinium salts are widely known as positive charge control agents, and Cr and Co-containing metal complex dyes, nitrofumic acid, etc. are widely known as negative charge control agents. There is. (Journal of the Society of Electrostatics, Vol. 4, No. 3, p. 144.) Among these, those using %Cr and Co-containing gold complex salt dyes as negative charge control agents have a certain level of chargeability, but the complex salt dyes themselves are Since it is water-soluble, it has poor compatibility with the binder resin, and when made into a toner, the toner has high hygroscopicity and lacks stability over time, resulting in poor repeated image formation ability.

The inventors of the present invention have conducted extensive studies to improve the drawbacks of these negative charge control agents, and have discovered that the above drawbacks can be overcome by incorporating the dye of formula (1) into the toner as a negative charge control agent. Completed the invention. The negative charge control agent according to the present invention has good compatibility with the binder resin, and the I-ner made using the same has a high specific charge amount and good stability over time, so it can be stored for a long time. A stable and clear image can be obtained.

The main use of toner containing a charge control agent is for electrostatic copying, which is widely used in office-related applications and often comes into direct contact with the human body.Therefore, there are various requirements for the sanitary safety of the chemicals used, for example, The charge control agents described in Japanese Patent Publication No. 41-20153, Japanese Patent Publication No. 7 I5-26478, and Japanese Patent Application Laid-open No. 56-35142 did not give good results in the mutagenicity test (Ames test), and improvement in this aspect is also desired. It was rare. However, the charge control agent of the present invention gave good results in the mutagenicity test, and also has excellent other properties required for a charge control agent as described above, so the value of the present invention is extremely large.

The dye represented by formula (1) is 4-chloro-2-aminephenol, 4-bromo-2-aminephenol, 4-sulfamido-2-aminephenol, 4-sulfomethyl-
Diazotizing amines such as 2-aminephenol or 4-sulfoethyl-2-aminephenol by a known method,
The monoazo dye obtained by coupling to β-naphthol is converted into a chromium complex by a known method, and then, for example, octylamine, decylamine, laurylamine, myristylamine, palmitylamine, cetylamine, 2-ethylbexyloxyglobylamine, etc. Alkylamines such as lauroxypropylamine, caproxypropylamine,
It can be obtained by salt formation treatment with an alkoxyalkylamine. Further, as a method for producing toner using the charge control agent 5- of the present invention, binder resin, charge control agent, coloring agent, etc. are melted and kneaded using a device capable of heat mixing such as a heating kneader and two rolls. and cooling,
The solidified material is processed through a grinder such as Geno+-Mill to
The binder resin is obtained by grinding to a particle size of 50'μ, or the binder resin is dissolved in a solvent, a charge control agent and a coloring agent are added thereto, and after stirring, the mixture is placed in water for recrystallization, subjected to E-filtration, dried, and then ball milled. There is a method of pulverizing the particles to a particle size of 1 to 50 μm.

In this case, the binder resin is polystyrene resin,
Acrylic resin, styrene-methacrylate copolymer,
Epoxy resin etc. and carbon black as a coloring agent.
Examples include, but are not limited to, pigments. The amount of the charge control agent of the present invention used is Q, 5 to 30 parts, preferably 05 to 10 parts, per 100 parts of the binder resin.
Department.

The present invention will be specifically explained below with reference to Examples.

-6 to In the examples, parts represent weight unless otherwise specified.

Example 1 Styrene-methacrylate copolymer 100 parts (2
) 5 parts of dye represented by the formula 20 parts of carbon black were mixed and melted and kneaded for 3 hours in a heating kneader.The kneaded product was taken out, cooled and solidified, and coarsely ground in a hammer mill. Grind with a jet mill, 1
Toner A was obtained by classifying the particles to have a particle size of ~10 μm.

On the other hand, as a comparison, toner 13 was produced in the same manner using a complex salt dye of the above formula (2) before salt formation treatment with tetradecylamine.

Regarding toner A and toner 13, the time of toner production and 100
About 200 mesh of iron powder was mixed with a weight ratio of 5:100 ()ner:iron powder) after being left in a humid environment for one week, and the specific charge amount of each was measured using a blow-off device (manufactured by Toshiba Chemical Corporation). As a result, we obtained the following results.

Table 1 Specific charge amount (×10 coulombs/z) As is clear from the comparison of the specific charge amount at the time of manufacture and after being left for one week, it is clear that toner A has extremely superior stability over time compared to toner B. be.

In addition, toner A and toner I3 were left in ioo% humidity for one week, and the copying machine (Ti'UJIXER,
When 1,000 copies were made using Toner OX 3500), copies using Toner A had higher image density and less background smudge than those using Toner I3. (Comparison at 1,000th copy) From the above tests, it is clear that dyes treated with salt formation provide toners with superior stability over time compared to dyes that are not treated with salt.

Example 2 Styrene oligomer resin 100 parts Dye represented by formula (3) 10 parts Carbon black
20 parts of carbon black was dissolved in 1000 parts of acetone (carbon black was in a dispersed state) and mixed for 2 hours at room temperature. Next, this mixture was poured into 10,000 parts of water under stirring and over-dried to obtain a toner in the form of coarse particles.

9- This material was further ground in a ball mill for 20 hours, and 5-1
The toner classified to 0μ is referred to as toner C.

As a comparison, toner D was obtained by using the complex salt dye of formula (3) before the salt formation treatment with amine and performing the same treatment as before.

The same tests as in Example 1 were conducted on Toner C and Toner D, and the results obtained were as follows.

Table 2: Specific charge amount (×lO coulomb/1) As shown in the above results, Toner C has extremely superior stability over time compared to Toner (2).

In addition, a copying test similar to that in Example 1 was conducted on Toner C,) Toner I] which was left in 100% humidity for one week. It gave copies with high density and less background smudge. (Comparison with the 10th copy of , , , 1, , O, 0, 0) The effect of the salt formation treatment as in Example 1 was clearly evident.

Example 3 200 parts of epoxy resin, 20 parts of dye represented by formula (4), and 20 parts of carbon blank were mixed, then melted and mixed using two heated rolls, cooled, and then mixed using a hammer mill equipped with a coarse powder frame classification device. It was classified into 1 to 10 microns using a jet mill to produce a toner.

The specific charge amount of this toner was measured in the same manner as in Example 1 immediately after production and after being left in a humidity of 100% for one week, and it was found to have extremely excellent stability over time.

Examples 4 to 7゜ Formulas (5) to (8) in place of the dye 2 (1) of Example 1
When a red age test similar to that in Example 1 was carried out using the dyes shown in the following, all dyes gave toners with high stability over time.

Comparative Example In Example 1, the following formula (9) was used instead of the dye of formula (2).
) and (10) were subjected to the same treatment as in Example 1 to produce toner G and ) toner H, respectively. For these and toner A obtained in Example 1, toner 13- was produced. The specific charge amount was measured immediately after and after being left in a humidity of 100% for one week. (Table 3) 14- Table 3 Specific charge amount (×10 coulombs/1) As shown in Table 3, toner obtained from a dye in which the salt-forming agent is a lower alkylamine (toner G), and a toner obtained from a known dye It is clear that the toner obtained from the dye according to the present invention has much better stability over time than the toner obtained from the dye (Toner H) and the like.

Patent applicant: Nippon Kayaku Co., Ltd. 15- 413-

Claims (1)

[Claims] (1) Formula (wherein X is CI, Br, SO□NH2,5O2CH3,
5O2C2H5 and A represents an alkyl ammonium having a straight chain or a branched chain having 8 to 16 carbon atoms or optionally interrupted by one oxygen atom. Toner for photo printing.