JPS6214168A - Liquid developer for electrostatic photography - Google Patents

Abstract

PURPOSE:To improve the fixability and uniformity of a toner layer by using capsules including a monomer or oligomer as a filler for preventing the lost contrast of transfer. CONSTITUTION:The filler for preventing the lost contrast of the transfer used in a liquid developer for electrostatic photography prepd. by dispersing toner particles and the filler for preventing the lost contrast of the transfer into an aliphat. hydrocarbon carrier liquid consists of the capsules each formed by coating a nuclear material essentially consisting of the monomer or oligomer with a shell material essentially consisting of a resin. Since the monomer or oligomer is incorporated into the capsules used for the filler for preventing the lost contrast of the transfer, the internal monomer or oligomer is fluidized and thermally polymerized when the shells of the capsules are cracked by the heat in the fixing stage, by which the toner layer is securely fixed and is introduced even into the small clearances in the recesses. The toner is thus made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to improvements in electrostatographic liquid developers containing anti-transfer crush fillers.

In the prior art, a single thin layer of toner was formed on a photoreceptor to obtain a certain degree of peta uniformity and sharpness. Developer containing filler to prevent transfer collapse (JP-A-49-34328 (US Pat. No. 3,915,874), US Pat. No. 57-178152, US Pat. No. 57-200049, US Pat. No. 58-298351)
etc., a thick toner layer is formed on the photoreceptor,
For paper with good smoothness, the sharpness is improved by the transfer crush prevention filler itself contained in the developer, and for paper with poor smoothness, the fixation effect of toner containing wax improves the uniformity of the image. We are planning to go paper-free.

However, in the case of conventional liquid developers, fixation is mainly performed by evaporation drying of the carrier liquid (drying temperature is about 180 to 200 degrees Celsius). When rubbed strongly, the previous toner layer could be removed, causing image stains and machine stains.

Purpose The purpose of the present invention is to use a capsule containing a monomer or oligomer as a filler to prevent transfer crushing.
It is an object of the present invention to provide a liquid developer for electrostatography which has improved toner fixing properties and uniformity.

Structure: The electrostatographic liquid developer of the present invention is characterized in that it consists of capsules coated with an electrostatographic liquid developer in which toner particles and a filler for preventing transfer crushing are dispersed in an aliphatic hydrocarbon carrier liquid. It is something to do.

In this way, the liquid developer of the present invention contains a monomer or oligomer in the capsule, which is a filler to prevent transfer collapse, so the outer shell of the capsule cracks due to the heat during fixing, and the monomer or oligomer inside flows and thermally polymerizes. In particular, the toner layer is firmly fixed and at the same time penetrates into the small gaps of the recesses and becomes uniform.

The capsule-type transfer collapse prevention filler used in the present invention can be produced by a spray drying method, a suspension polymerization method using a chain transfer agent and a polymerization inhibitor in combination, or a microencapsulation method such as an in-aitu polymerization method. . These methods are described, for example, in "Granulation Handbook" (Japan Powder Industry Association). This anti-transfer filler consists of a capsule whose main component is a monomer or oligomer as a core material, and whose surface is covered with an outer shell material whose main component is a resin insoluble in a carrier liquid. What becomes nuclear material here! -Or any oligomer can be used as long as it is thermally polymerizable, such as lauryl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, oleyl methacrylate,
Examples include vinyl monomers such as divinylbenzene, methyl methacrylate, methyl acrylate, ethyl methacrylate, styrene, glycidyl methacrylate, and methacrylic acid, and mixtures thereof. These monomers or oligomers include paraffinic or isoparaffinic hydrocarbon solvents for the carrier liquid, such as ligroin, n-hexane, n-hebutane, 1so-octane, n-octane, carbon tetrachloride, etc. (commercially available products include Esso's Isopar H, G,
L, Ni; Naphsamuro; Tsurpets 100, etc.) can be used in combination.

On the other hand, any resin that is insoluble in the carrier liquid can be used as the outer shell material. For example, polyvinyl resins such as 4-dimethyl methacrylate, polyethyl methacrylate, polyvinyl chloride, polystyrene, and polyvinylidene fluoride can be used. Can be mentioned.

The particle size of the transfer crushing prevention filler as described above is 10 to 20.
It is preferably about μ. Also, the amount used is 0.01 to 2 of the developer.
% (weight) is appropriate.

The filler to prevent transfer crushing contains Carzen Black as a dispersion colorant (commercially available products such as Printex G, V, U, Special Black 15, manufactured by Degussa).
4.4B; Mitsubishi Kasei #44゜$30. MR-11.
M^100; Mogul L, Black No. 4 manufactured by Casette
-ru 1300゜1100.900, jigal 400,6
60; Neo Spectra Mark 1 manufactured by Columbia Car 2F
1 Raven 1035.1252), and phthalocyanine blue, phthalocyanine green, sky blue, rhodamine lake, malachite green lake,
Methyl violet lake, peacock blue lake,
Naphthol Green B1 Naphthol Green Y1 Naphthol Yellow S, IJ Sole Fast Yellow 2G,
Permanent Red 4R, Blue IJ IJ Antofast Scarlet, Hansa Yellow, Benzidine Yellow, Resole Red, Lake Red C Blue Red D1 Brilliant Carmine 6B, Nozoichi Manent Red F 5
R, Pigment Scarlet 3B and Zeldor 10B
Organic pigments such as can be used in combination. In addition, when such a coloring agent for dispersion is used, it is of course preferable to use one having the same color as the coloring agent used in the toner particles.

The toner particles used in the present invention are mainly composed of a resin and a colorant, as in the past, and it is preferable to add waxes to improve the fixability and flat filling. What is toner resin? -C00CnII2n+1 (n=6
~20)], acrylic acid, methacrylic acid, and vinyl R are -COOCnH2n+1 (n=1~
5)] is H or CH3, f is -N (CH8)
, -N (C,H,)2, -0H] and a copolymer or graft copolymer of at least one monomer B of ethylene glycol dimethacrylate. The proportion of monomers in the copolymer or graft copolymer is preferably 30 to 95%.

These copolymers include natural resins such as ester gum and hardened rosin, natural resin-modified maleic acid resin, natural resin-modified phenol resin, natural resin-modified polyester resin, natural resin-modified pentaerythritol resin, and epoxy resin. A modified thermosetting resin may also be used.

Specific examples of the colorant for toner are the same as those for the colorant for dispersion.

As waxes, those having a relatively low softening point, such as paraffin wax and polyethylene wax, are used. Commercially available products include the following.

Genuine Chemical Paraffin Wax 60~
98 Kobayashi Kako Sarashi Mitsuro
65 Setanol 80 Nagai Kako Exposed Hitsuro 65
Steel Chemical Flowene 11O
N-12113 N-14106 N-34103 N-45118 C-10104 C-13110 C-15102 C-16106 E-10106 a-tt toaE-
12112 g-14104 E-15100 Mitsui Petrochemical 110P 1002
20P 113 220MP 113 320MP 114 410MP 122 210MP 120 310MP 122 405MP l 26200P
128 4202E 108 Manufacturer Product name Softening point (”
C) 4053E 1
itB A S F OA wax 9
3~96 Petrolite BARECO50086BAR
ECO655102 BARICO100O113 BARECO2000125 g73o 93 E2018 117 E2020 117 PETRONABAC-750097,8 Hoechst
P E 520 11 to 123 pgta
o 122～127PED l 21
11t118PED136 10
7-112PED 153 115-120
PED521 10to108PED522
10Ch105PED534
9to105 Manufacturer Product Name
Softening point CG) Allied Chemical AC-Polyethylene 1702 98AC-Polyethylene G161
102^C-Polyethylene 615 105 Sanyo Chemical Sunwax 131-P 10
g Sunwax 151-P IQT Sunwax 161-P 111 Sunwax 165
-P 107 Sunwax 1F 1-P
105 Sunwax E-20095 Union Carnoid DYNI
102DYNF
102DYNE (102D YN J 102D
YNK 102% 7santo 0RLIZON 805 1
160RLIZON 705 11
60RLIZON 50 126
Philips MARLEX 1005
92Duboy ALATHON-31
03 Manufacturer Product name LATI with softening point ('C) (ONI O96 ALATHON12 84A
LATHONI 4 80A
LATHON16 95 people LATI
(ON20 s aALAT
HON22s 4ALA
When preparing a developer, waxes such as THON25 96 and above can be poured into a disperser such as an Attritor, Lumil, Kiteimir, etc. as a powder and dispersed together with other developer materials, or they can be heated and dissolved in a carrier liquid and then rapidly cooled. Bring it to a swollen state, and then put it into a disperser and disperse it in the same way, or
As shown in JP-A No. 57-186758, processed pigments may be prepared and similarly introduced into a disperser and dispersed, or JP-A No. 50-993
They may be dispersed in a toner resin as shown in No. 31, or by any of these methods.

Specific examples of the carrier liquid are as described above.

To prepare the liquid developer of the present invention using the above materials, 5 to 40 parts by weight of colorant, 5 to 40 parts by weight of resin, and preferably 20 to 60 parts by weight of wax are added to 300 to 300 parts by weight of carrier liquid.
The toner may be dispersed with 600 parts by weight using an attritor, Zeel mill, Kitei mill, etc. to obtain a concentrated toner, and this may be diluted 5 to 10 times with a similar carrier liquid.

The present invention will be explained below by way of examples. Note that both parts and % are based on weighted IT.

Example 60 parts of isooctane and styrene/divinylbenzene = 1
20 parts of mixed monomers at a ratio of 0:1 (weight ratio), 0.5 parts of benzoyl peroxide, and 20 parts of Kazen black (Mogal L manufactured by Casette) were mixed, and this was mixed with 0.5 parts of potassium persulfate and 5 parts of gum arabic. The mixture was emulsified and dispersed in 500 parts of an aqueous solution containing 0.5 parts, and heated at 80° C. for 6 hours with stirring.

Then, the obtained capsules containing the monomer mixture and isooctane were washed with water, dried, and classified using a zigzag classifier 100MZR manufactured by Albine Co., Ltd. to obtain a volume average particle size of 15.
A 3μ transfer crushing prevention filler A was obtained.

On the other hand, for comparison, 50 parts of styrene monomer, dispersant (
1.5 parts of Tween 80 (manufactured by Kanto Kagaku Co., Ltd.) and 0.4 parts of isoazopiscyclohexanecarzenyl (manufactured by Ogaki Kagaku Co., Ltd.) as a polymerization initiator were dispersed in 500 parts of water,
The mixture was heated at 75° C. for 5 hours with stirring. The obtained polystyrene particles were washed with water, dried, and classified in the same manner to obtain a transfer crushing prevention agent B having a volume average particle diameter of 15.0 μm.

Next, 45 parts of a 50% solution of Einpar H (manufactured by Exxon) of a copolymer of lauryl methacrylate, hydroxyethyl methacrylate, acrylic acid and methyl methacrylate (weight ratio 40/15/15/10) was added.
Black (Black No Sale 900 manufactured by Colombia Carden)
12 parts alkali blue (manufactured by Orient Chemical Co., Ltd.)
3 parts of the resulting creamy wax dispersion
25 (1) Put the different materials into a Zeel mill, disperse for 72 hours, add 360 parts of Isopar H, disperse for another hour to make a concentrated toner, and add 140 parts of it to Aitsuno$-H.
The developer was diluted with 750 parts, and transfer crushing prevention fillers A and B were added thereto to give a concentration of 1% to prepare a liquid developer of the present invention and a comparative liquid developer, respectively.

Next, each developer was set in a commercially available wet transfer electrophotographic copying machine (DT-5200 manufactured by Ricoh, modified so that the maximum surface potential was 1500 V), and typing paper (Gilchrest Send) was used as transfer paper. Akusuka White)
When the image was printed using the product of the present invention, it was possible to fill in the small gaps in the recesses of the transfer paper, and even if the image was rubbed immediately after printing, the image did not get smudged. In the case of the comparative product, the image had a 6t (6t) meso effect and the fixing performance was also not sufficient.

Effects As described above, since the liquid developer of the present invention uses a transfer collapse prevention agent consisting of capsules containing monomers or oligomers, the outer shell of the capsules cracks due to the drying heat during fixing, causing the monomers or oligomers inside to flow and heat. Polymerization has the advantage of firmly fixing the toner image and making it uniform.

Claims (1)

[Claims] 1. In an electrostatographic liquid developer in which toner particles and a transfer crushing prevention filler are dispersed in an aliphatic hydrocarbon carrier liquid, the transfer crushing prevention filler contains a core material mainly composed of monomers or oligomers and a resin. A liquid developer for electrostatic photography, characterized in that it consists of capsules covered with an outer shell material as a main component.