JPH0136097B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatographic liquid developer for forming blue-tone images.

Conventionally, liquid developers for forming blue images used in electrophotography such as electrophotography, color electrophotography, and electrostatic photography include colorants containing blue pigments such as phthalocyanine blue, sky blue, and peacock blue, and acrylics. The main component is a natural or synthetic resin such as resin, styrene resin, phenol-modified alkyd resin, rosin, or synthetic rubber, and a polarity control agent that also has a dispersion stabilizing effect such as lecithin, metal soap, linseed oil, or higher fatty acid is added to this. A toner dispersed in an insulating carrier liquid such as a petroleum-based aliphatic hydrocarbon is used. Development is carried out using such a liquid developer by immersing an electrophotographic photosensitive member or an electrostatic recording member having an electrostatic latent image therein. In this case, the toner in the developer causes electrophoresis according to the charge of the electrostatic latent image on the photoreceptor or recording medium, and is fixed on the surface to form a copied image. Liquid developers for forming blue images have drawbacks such as over time, the polarity control agent dissolves into the carrier liquid and loses its function, resulting in the polarity becoming unclear, reducing image density, and causing aggregation. It was hot. Therefore, in order to eliminate these drawbacks, attempts have been made to introduce a polar group having the same effect as a polarity control agent into a blue pigment such as a phthalocyanine pigment. A halogen-substituted phthalocyanine pigment is an example of this, but when a halogen is directly bonded and introduced into a blue pigment, the original color tone changes significantly (in the case of the above example, it changes from blue to green). The drawback is that it cannot be used as a blue pigment. In fact, examples of halogen-substituted phthalocyanine pigments are CI Pigment Green 7 (14 to 16 Cl), CI Pigment Green 36 (10 Cl,
6 Br), 37 (8 Cl), 38 ((4 Br + 8 Cl) ~
(12 Br + 3 Cl), CI74120 (product example Heliogen Green, 14 to 15 Cl), etc. All of these colors indicate that the blue color of the phthalocyanine pigment changes to green by directly bonding halogen. It shows.

The purpose of the present invention is to use a blue pigment that does not change in color even though polar groups are introduced.
An object of the present invention is to provide a liquid developer for electrostatography that has improved polarity controllability and dispersion stability.

That is, the developer of the present invention is an electrostatographic liquid developer comprising toner particles mainly composed of a colorant and a resin dispersed in an insulating carrier liquid, in which at least one chloromethyl group is contained in the colorant. It is characterized by containing a metal phthalocyanine and/or metal-free phthalocyanine pigment substituted with .

The chloromethyl group-substituted metal phthalocyanine or metal-free phthalocyanine used as the colorant constituting the toner particles in the present invention has the following general formula:
A blue pigment represented by , which is produced by chloromethylating metal phthalocyanine or metal-free phthalocyanine, but is generally obtained as a mixture of di-substituted, mono-substituted and unsubstituted products, and is not actually commercially available as a mixture. There is. However, these mixtures generally cannot be isolated, and it is difficult and meaningless to confirm the position of the chloromethyl group in the molecule. Therefore, the blue pigment (mixture) used in the present invention has a It is expressed as the average number of chloromethyl group substitutions. It is useful for the blue pigment of the present invention to have an average number of substitutions of 1 to 3 chloromethyl groups.

(However, R ₁ to R ₁₆ are -H or -CH ₂ Cl, -
Contains at least one CH ₂ Cl. Also, M is Cu, Ni,
Indicates Co, Al, Fe or Sn. Note that the chloromethyl group in the above general formula is a polar group that has a polarity controlling effect and a dispersion stabilizing effect, but it has the feature that it does not change the color tone as in the conventional case. .

These blue pigments can be used in combination with carbon black and other pigments, if necessary.

In addition, the resin, which is another component constituting the toner particles, mainly has the effect of dispersing and stabilizing the toner particles, and specifically, as in the past, acrylic resin, styrene resin, alkyd resin, rosin, synthetic rubber, or Copolymers of monomers constituting these resins can be used. The amount used is approximately 0.1 to 10 parts by weight per 1 part by weight of the colorant.

Examples of the insulating carrier liquid include petroleum aliphatic hydrocarbons or their halogen derivatives, such as n-hexane, ligroin, n-pentane, n-peptane, isooctane, n-octane, isododecane, carbon tetrachloride, perchlorethylene, freon, etc. (Commercially available products include Isopar G, Isopar H, Isopar L,
Isopar K, Naphtha No. 6, Solbetune 150, Daiflon, Cierzol 71, etc.) are used.

To prepare the liquid developer of the present invention, a predetermined amount of colorant and resin may be kneaded in the presence of a small amount of carrier liquid to form a concentrated toner, and this may be dispersed in the carrier liquid.

The liquid developer for forming blue images of the present invention obtained as described above can be used for electrophotography, color electrophotography,
It is used in the field of electrostatic photography such as electrostatic recording and electrostatic printing, but because it uses a blue pigment with polar groups introduced as described above, there is no possibility that image density will decrease or aggregation will occur over time. do not have.

Examples are shown below.

Example 1 2 g of a copper phthalocyanine mixture with an average number of chloromethyl groups of 1.6 styrene/lauryl methacrylate (weight ratio
A composition consisting of 60 g of 10/90) copolymer and 38 g of Isopar G was kneaded and dispersed in a ball mill for 50 hours to obtain a concentrated toner, and the entire amount was diluted with 1 part of Isopar G to prepare a liquid developer. Next, this developer was used to develop the electrostatic latent image previously formed on the selenium photoreceptor, and the resulting image was transferred onto plain paper using a conventional method, resulting in a blue copy with an image density of 0.72. Ta. Also, this developer is heated at a temperature of 50℃.
After being left for 30 days for forced deterioration, development was carried out in the same manner, but the density of the obtained image was 0.65, which was almost no different from that before forced deterioration. Also, no sedimentation or aggregation occurred during forced aging.

Example 2 Carbon black 10g Same as Example 1, average number of chloromethyl groups is 1.6
A composition consisting of 8 g of copper phthalocyanine mixture, 50 g of the same copolymer as in Example 1, and 50 g of Isopar G was kneaded and dispersed in the same manner as in Example 1 to obtain a concentrated toner, and 15 g of the same was mixed with Isopar G2.
A liquid developer was prepared by dispersing it in Thereafter, development was carried out in the same manner as in Example 1 using this developer, and a copy with an image density of 1.20 was obtained. on the other hand,
For comparison, in the case of a developer prepared using the same method except that Peacotook Blue was used instead of the copper phthalocyanine mixture, the image density was relatively high at 0.95, but copies with many background stains were obtained. Ta.

Example 3 Blue pigment with an average number of chloromethyl groups of 1.4
A liquid developer was prepared and developed in the same manner as in Example 1, except that a cobalt phthalocyanine mixture of 1 was used, and a green-blue copy with an image density of 0.69 was obtained. Next, this developer was forcibly degraded in the same manner as in Example 1, and then development was performed, and the image density was 0.63, with almost no difference. Also, no sedimentation or aggregation occurred during forced aging.

Example 4 A liquid developer was prepared in the same manner as in Example 1 except that a nickel phthalocyanine mixture having an average of 1.5 chloromethyl groups was used as the blue pigment. When the developer was developed in the same manner as in Example 1, the initial image density was 0.65, and the image density after forced deterioration was 0.65.
A blue copy with almost the same value as 0.60 was obtained. Furthermore, no sedimentation or aggregation occurred during forced deterioration.

Example 5 A liquid developer was prepared in the same manner as in Example 1 except that an iron phthalocyanine mixture having an average of 1.4 chloromethyl groups was used as the blue pigment, and development was carried out in the same manner as in Example 1 using this developer. However, a blue copy with an initial image density of 0.58 and an image density after forced deterioration of 0.47 was obtained. Furthermore, no sedimentation or aggregation occurred during forced deterioration.

Example 6 A liquid developer was prepared in the same manner as in Example 1 except that a tin phthalocyanine mixture having an average of 1.4 chloromethyl groups was used as the blue pigment, and development was carried out in the same manner as in Example 1. Initial image density
0.55, and a blue copy with an image density of 0.45 after forced aging was obtained. Furthermore, no sedimentation or aggregation was observed during forced deterioration.

Example 7 A liquid developer was prepared in the same manner as in Example 1 except that an aluminum phthalocyanine mixture having an average of 1.4 chloromethyl groups was used as the blue pigment, and development was carried out in the same manner as in Example 1. A blue copy was obtained with an initial image density of 0.49 and an image density of 0.45 after forced aging. Furthermore, no sedimentation or aggregation was observed during forced deterioration.

Example 8 A liquid developer was prepared in the same manner as in Example 1 except that a phthalocyanine mixture having an average of 1.4 chloromethyl groups was used as a blue pigment, and development was carried out in the same manner as in Example 1. image density
0.68, a blue copy with an image density of 0.60 after forced aging was obtained.

Example 9 A liquid developer was prepared in the same manner as in Example 2 except that the same blue pigment as in Example 8 was used,
Thereafter, development was carried out in the same manner as in Example 1, and a blue copy with an initial image density of 1.20 was obtained.

Claims (1)

[Claims] 1. In an electrostatic photographic liquid developer comprising toner particles mainly composed of a colorant and a resin dispersed in an insulating carrier liquid, the colorant contains a metal substituted with at least one chloromethyl group. A liquid developer for electrostatic photography, characterized in that it contains a phthalocyanine and/or a metal-free phthalocyanine pigment.