JPS6247650A - Color liquid developer for electrostatic photography - Google Patents

Abstract

PURPOSE:To obtain the titled developer having improved properties of a gradation reproducibility, a dispersing stability, a fixing property and a color reproducibility by using a colorant which is obtd. by effecting a fluch-treatment of a dyestuff and a pigment composed of a specific naphthol derivative with a resin as the colorant of the titled developer. CONSTITUTION:The prescribed colorant is prepared by flush-treating a hydrous paste of the dyestuff and the pigment (for example, compds. of formulas III and IV) shown by formula I (wherein R is a group shown by formula II or its substd., X<1>-X<7> are each H, NO2, NO, NH2, a lower alkyl group or a halogen atom) and the resin (such as a polypropylene resin and a vinyl chloride resin) having 50-120 deg.C a softening point in a flusher. The titled developer is prepared by mixing the flush-treated prescribed colorant and the binder (for example, an alkyd resin and a polymethacrylester resin) and a small amount of a carrier liquid (such as a paraffin hydrocarbon and a ligroin) in a ball mill.

Description

[Detailed Description of the Invention] The present invention relates to a liquid developer for electrostatic photography, and more specifically, a color liquid for electrostatic photography that uses a toner component as a coloring agent obtained by flashing a specific dye and pigment. Regarding developer.

BACKGROUND ART A liquid developer for electrostatic photography is well known, which is made by uniformly dispersing a toner coated with an inorganic or organic pigment with a resin (binder) in a highly insulating and low dielectric constant carrier liquid ( Japanese Patent Application Publication 1973-
No. 151528, No. 53-109633, No. 55-1
44252 etc.). This product generally uses pigment as resin,
It is obtained by crushing and dispersing the toner together with a carrier liquid using a ball mill, etc. However, with this method, the toner is not dispersed down to the primary particles, resulting in poor transparency, rough images, and high sedimentation. There is a problem that the sediment causes caking.

Furthermore, dyeing latex with dye and applying this to toner is also being considered (Japanese Patent Laid-Open No. 45-25878
No. 56-10619, etc.). However, this method has a problem in that the absolute density is low and, in addition, if the dye that has not penetrated into the latex is not completely removed, background fogging may occur.

However, as a means of manufacturing a liquid developer that improves these, (i) JP-A-57-34720, JP-A-57-193;
As seen in publications such as No. 73, wax and pigment are dispersed in a heated carrier liquid and rapidly cooled to perform a wax treatment on the pigment, and then dispersed together with a resin in the carrier liquid; As seen in Japanese Patent Publication No. 57-201248, it has been proposed to knead wax and pigment, spray granulate the mixture with a spray dryer, and disperse this together with a resin in a carrier liquid. However, in all of these cases, the compatibility between the wax and the pigment is poor, so the toner is still not dispersed down to the primary particles, resulting in poor transparency and poor drying properties, especially in overhead projectors (OHP). When projected, it appears blackish and has the disadvantage of insufficient color reproducibility.

II-1 Direction The first object of the present invention is to provide a color liquid developer for electrostatic photography, which contains a toner component that is a colorant that is insoluble in a carrier liquid and has excellent dispersion stability and drying properties. .

A second object of the present invention is to provide a color liquid developer for electrostatic photography that has excellent gradation reproducibility, drying properties, transparency, etc., and exhibits good color reproducibility especially when used in OHP. It is.

Structure The present invention provides a color liquid developer for electrostatic photography, which comprises toner particles containing a colorant and a binder as main components dispersed in an aliphatic hydrocarbon carrier liquid, wherein the colorant has the following general formula (I). (However, R is -N=N-@ or a substituted product thereof.

X1 to X7 are -H1-No2, -No, -NH2, a lower alkyl group or a halogen. ) is characterized by being flushed with a resin having a softening point of 50 to 120°C.

Incidentally, it has not been thought to use inorganic or organic pigments such as carbon black and phthalocyanine blue as colorants for toners by flashing treatment.

However, when a resin that is soluble in a carrier liquid is used as a resin for flushing processing, the resin dissolves in the carrier liquid used for toner dispersion, so depending on the type of resin, it may lower the electrical resistance of the carrier liquid or destabilizes the polarity of

Further, in some cases, as a result of inversion, the image density may decrease or background smear may occur, making it impossible to form a clear image. Therefore, colorant resins that are insoluble or poorly soluble in the carrier liquid are generally used. However, in the past, unless measures were taken such as taking into consideration the compatibility formulation balance between pigment and resin during colorant production or dispersing for a long time during toner production, the toner deteriorated in the developer over time. Dispersion stability is reduced due to sedimentation and aggregation, and the resulting copies have disadvantages such as poor drying properties, poor subsequent fixing properties, and easy set-off.

The present invention achieves the intended purpose by specifying and combining dyes and pigments and resins.

As mentioned above, the liquid developer according to the present invention has the general formula (
The pigment (dye) represented by I) subjected to flashing treatment is used as a toner component. Therefore, we will proceed with the explanation of the "puff flushing process."

In the flashing process, first, a pigment or a water-containing paste of the pigment is placed in a kneader called a flasher together with a resin or a resin solution and mixed well. During this process, the water present around the pigment is replaced by the resin solution. This is removed from the kneader, the aqueous phase is discarded, the pigment dispersed in the resin solution is dried, the solvent is removed, and the resulting lumps are pulverized. In the present invention, this material is referred to as a "flushing-treated colorant." Note that it is also possible to use a method of removing water and solvent under reduced pressure while kneading with a kneader.

Flushing treatment is known to provide very good dispersion because a water-containing paste can be used as a material and the treatment can be performed while kneading with a kneader. Also,
In the flushing process, by mixing not only the pigment but also the dye with water in the form of a slurry, almost the same effect as the pigment can be obtained. Therefore, in the present invention, dyes that are subjected to flushing treatment can also be employed as toner components.

The dye and pigment used in the present invention are naphthol derivatives represented by the above general formula (I). Representative examples of such dyes and pigments include the following.

(Nα1) CI Pigment Red 164-nitro-〇-anisidine → 3-hydroxy-N-1-naphthyl-2-naphthamide (Nα2) 2-nitro-p-anisidine → 3-hydroxy-N-
1-naphthyl-2-naphthamide (N(I3) (Nci5) (Nα6) (Nα9) The following resins can be exemplified as resins used in flashing treatment of these dyes and pigments.

Manufacturer name Product name Softening point ('C) Eastman Chemical N-10111N-11108 N-12113 N-14106 N-34103 N-45118 C-10104 C-13110 C-15102 C-16106 E-10106 E-11106 E -12112 E-14104 E-15100 Mitsui Petrochemical 110P 100220P
113 220MP 113 320MP 114 210MP 120 4202E 108 4053E 111 Manufacturer name Product name ■ bE2 [BASF
OA wax 93-96 petrolite BARECO50086BARECO65
5102 BARECO1000113 E 730 93 E2018 117 E2020 117 E 1040 105 PETRONABA C90,5 PETRONABA C-369 (L, SPE RON
ABA C-400104,5PETRONABA
C-750097,8PE520 118-1
20 P E 0121 113-118 Hoechst
PED1.36 107~112PED15
3 115~120 PED521 103~108 PED522 100~105PED534
98-105 Allied Chemical AC-Polyethylene 6&6A
102AC-Polyethylene 615 105 Sanyo Chemical Sunwax 131-P 108 Sunwax 151-P 107 Sunwax 161-P 111 Sunwax 165-P 107 Sunwax 171-P 105 Manufacturer name Product name Softening point (°C) Union Carbide D Y N I 102
D Y N F 102 D Y N H102 D Y N J 102 D Y N K 102 Monsanto 0RLIZON 805 1160R
LIZON 705 116 PHILLIPS MAR
[, EX 1005 92 Dupont ALA
TIION 3 103ALATION to
96ALATHON 12 84 ALATHON 14 80 ALAT11ON 16 95ALATI(O
N 20 86ALATION 22
84ALAT■ON 25 96 In addition to the above, polyethylene resins include Sunwax E200, E250P (manufactured by Sanyo Chemical Co., Ltd.), 2000
．． 2500.3000.4000.4100.8000
B, 5000.6000.7000 (manufactured by Chubu Polyethylene Co., Ltd.), Viscol 500P, 660P (manufactured by Sanyo Chemical Co., Ltd.) as polypropylene resin, Denga Vinyl 5S-1,00,5S- as vinyl chloride resin
130, DSS-130, 5S-140, 5S-80,
5S-70, 5S-Y, 5H-250, 5H-17
0, M-70, M-120, MM-90, EM-140
, VP-30, 3E-130, ME-120, ME-1
80, MHE-100, PA-100, P-80 (manufactured by Denki Kagaku Kogyo Co., Ltd.), paraffin wax (softening point 5
0 to 98°C), beeswax (softening point: about 60°C), natural wax (softening point: about 51°C), and the like.

The appropriate ratio of the dye and pigment to the resin in such flushing treatment is 0.1 to 6.0 parts by weight, preferably 0.1 to 0.6 parts by weight, of the resin per 1 part by weight of the dye and pigment.

To prepare a liquid developer using the "flushed colorant" thus obtained, the colorant and binder are mixed with a small amount of carrier liquid in an attritor, a ball mill,
The toner may be kneaded and dispersed using a kitty mill or the like to obtain a concentrated toner, and if necessary, this may be diluted approximately 5 to 10 times with a similar carrier liquid. The ratio of colorant to binder is suitably 1:1 to 10 (by weight).

The binders used here include alkyd resins, resin-modified phenol formaldehyde resins, polyhydric alcohol esters of hydrogenated rosin, polyacrylic or polymethaglyl ester resins, styrene resins, and chlorinated rubbers, but in particular the following General formula (■) [However, R1 is hydrogen or methyl group, R2 is -C○○
CnH2n+□ or -〇COCn H2n + □(n
is an integer from 6 to 20). ] A monomer represented by acrylic acid, methacrylic acid, vinylpyridine, the following general formula (III) [wherein R3 is hydrogen or a methyl group, R4 is -C00CnH2n+ or -○COC0H2n+z (n is an integer from 1 to 5) be. ] The following general formula (IV) [however,
R5 is hydrogen or a methyl group, R6 is -N(CH,)2.
-N(C2H5)2 or -〇〇. ] It is effective to use a copolymer (including a block copolymer) with one or more monomers selected from the following monomers and ethylene glycol dimethacrylate. The appropriate proportion of the vinyl monomer component represented by formula (II) in the copolymer is about 30 to 95% by weight.

As a binder, if necessary, ester gum; natural resins such as softened rosin, natural resin-modified maleic acid resin, and natural resin-modified phenol resin.

Natural resin-modified thermosetting resins such as natural resin-modified polyester resins, natural resin-modified pentaerythritol resins, and epoxy resins may be added.

The carrier liquid may be paraffinic or isoparaffinic hydrocarbon (Isopar H, Isopar G manufactured by Esso).
, Isopar L, Isopar K, Naphtha & 6 Sorbetso 100, etc.), ligroin, n-hexane, n-hebutane + 1so-octane, n-octane, carbon tetrachloride,
l-lichlorotrifluoroethane, cyclohexane, etc. may be used alone or in combination of two or more.

The thus obtained orange to red liquid developer of the present invention has (i) dye and pigments that are dispersed in a state close to primary particles, which makes them difficult to aggregate, and (ii) primary particles of dye and pigments that have a softening point of 50 to 120. Because it is coated with resin at ℃, the colorant is well fixed on the transfer paper by heating and fixing the copy using a copying machine.Furthermore, the toner particle size is small, so it has particularly excellent gradation reproducibility, and it can be used on OHP. This ensures good color reproducibility.

Here, an example of producing a colorant in which a dye or pigment represented by the general formula (I) is subjected to a flushing treatment with a resin having a softening point of 50 to 120 DEG C. is as follows.

Production Example 1 2000g of R1 dye/pigment cake (pigment content: 500g)
) was placed in a kneader, 1500 g of bleached beeswax in toluene solvent (solid content 30%) was added thereto, and the mixture was kneaded at 100°C for 3 hours. Then, after separating off the water, the solvent was removed in vacuo. This treated product was cooled and ground in a stone mill to obtain a colorant.

Production Example 2 Nα2 dye and pigment cake-like product 10100O pigment content 500
g) was placed in a kneader, and 2000 g of a xylene solution (solid content 30%) of polyethylene (Sunwax 131 P manufactured by Sanyo Chemical Co., Ltd.) was added thereto and kneaded at 130° C. for 2 hours. Next, in the same manner as in Production Example 1, the solvent and water were removed and the mixture was pulverized to obtain a colorant.

Production Example 3 A cake-like product of the dye and pigment of Nα3 1000 [(pigment content 5
00g) to 130℃, and polyethylene (
2000 g of a xylene solution (solid content: 50%, liquid temperature: 130° C.) of AC-6 manufactured by Allied Chemical Co., Ltd. was added and kneaded for 1 hour. Next, in the same manner as in Production Example 1, the solvent and water were removed and the mixture was pulverized to obtain a colorant.

Comparative production example Nα3 dye and pigment cake-like product 10100O pigment content 400
g) to 130°C, and add Hiwax 405 in it.
2,000 g of a xylene solution (solid content: 50%, liquid temperature: 130°C) of MP (manufactured by Mitsui Petrochemical Co., Ltd.; softening point: 126°C) was added and kneaded for 1 hour. Next, in the same manner as in Production Example 1, the solvent and water were removed and the mixture was pulverized to obtain a colorant.

Examples and comparative examples using the above coloring agent are as follows.

20 g of the flushed naphthol derivatives obtained in Production Examples 1 to 3 and Comparative Production Examples and acrylic copolymer (
An isooctane solution of lauryl methacrylate (n-butyl methacrylate/methacrylic acid copolymer) (solid content:
0%) loog in a ball mill at 30°C.
The toner was dispersed for 0 hours to obtain a concentrated toner, and 15O-G (manufactured by Exxon) was added to IQ to dilute it to prepare a liquid developer.

Next, using this liquid developer, a commercially available electrophotographic copying machine (
Copying was carried out using a Ricoh DT-5700) and the results shown in Table 1 were obtained.

In the table, O means extremely good, O means good, and Δ means fair.

Table-1 Notes: 1) Agreed using the Macbeth densitometer.

-2) Evaluation was made based on how many steps of the original Kodak gray scale (20 steps) were reproduced.

Umbrella 3) The above line of the actual firing image is divided by the original chart lnv line.

-) Evaluated by surface drying time.

Umbrella 5) Evaluation was made by observing the caking state and sedimentation separation state after being left for 7 days.

Effects As is clear from the description of the examples, the liquid developer of the present invention has excellent gradation reproducibility, storage stability (dispersion stability), and fixing properties, especially color reproduction when using ○HP. It is something that improves sexuality.

Claims (1)

[Claims] 1. A liquid developer comprising a toner mainly composed of a colorant and a binder dispersed in an aliphatic hydrocarbon carrier liquid, wherein the colorant has the following general formula (I) ▲Math. , chemical formulas, tables, etc. ▼...(I) (However, R is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or its substitutes, X^1 to X^7 are -H, -NO_2, -NO , -NH_
2. Lower alkyl group or halogen. 1. A color liquid developer for electrostatic photography, characterized in that the dye and pigment represented by: