Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1998-08-14
2000-07-11
Hoke, Veronica P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
106472, 106478, C08K 304
Patent
active
060874341
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a pigment composition for liquid toner, a process for producing the pigment composition and a process for producing the liquid toner.
2. Background Art
The printing speed of a wet-type electrophotographic printing system is inferior to that of a commercially available offset printing press, but in general, is far superior to that of a dry-type copying machine. Besides, unlike the commercially available offset printing press, the wet-type electrophotographic printing system can provide a print having an image quality as high as that of a photograph (resolution: 800 DIP or more) at a reduced printing cost without replacement of printing plates.
In the above-mentioned wet-type electrophotographic printing system, the development of images is conducted by using a so-called liquid toner. This liquid toner primarily is comprises an electrically insulating liquid and pigment fine particles dispersed therein. More specifically, the liquid toner comprises an electrically insulating carrier liquid (having an electrical resistance of 10.sup.9 to 10.sup.15 .OMEGA./cm), coloring particles dispersed in the carrier liquid, a resin soluble in the electrically insulating liquid, a charge controlling agent for charging the coloring particles to positive or negative potential, and various additives. As the pigment fine particles, there have been used carbon black and various non-black pigments. Incidentally, the above-mentioned resin has been used for the purpose of dispersing or fixing the coloring particles.
Meanwhile, in general, in the case of carbon black, the inclusion of impurities (so-called grits) comprising mainly metals or the like and having a particle diameter of not less than 44 .mu.m cannot be avoided in view of its production method. The commercially available carbon blacks have contained at least 50 ppm of such grits. The above-mentioned grits result from coke particles produced in an oven simultaneously with the production of carbon black, or chips or spalls of brick, and from a heat exchanger.
However, in case where such carbon black containing a large amount of grits or ash is used in the liquid toner, there have been caused not only damage to a photosensitive member but also non-uniformity in dot configuration in prints. For this reason, in the above-mentioned liquid toners. Therefore, it is one of important problems to use strictly selected carbon black containing less amount of grits or ash.
Further, in case where the liquid toners has the low zeta (.zeta.) potential, there have been caused insufficient print density or non-uniformity in dot configuration. For this reason, it is one of important problems how to solve it.
Meanwhile, in the case of conventional liquid toners, when raw materials therefor are handled in the production process, or when the wet-type electrophotographic printers using these toners are repaired or inspected, there have been discussions concerning influence on a human body caused when carbon black or carbon black-containing toner is erroneously inhaled or sucked by the operators, or concerning environmental pollution. Accordingly, it has been demanded to provide safe carbon black which causes no significant influence on human body even when inhaled or sucked. In addition, when pigment is not sufficiently dispersed in the liquid toner, there have been caused problems such as insufficient print density or non-uniformity in dot configuration. For this reason, it is also an important problem how to disperse the pigment in the toner in a good condition.
Further, in the case where the liquid toners contain insufficiently dispersed masses produced mainly in a dispersion step of the pigment, or impurities or foreign substances incorporated mainly in the toner production step, there arise various problems including not only deterioration in resolving power, image density or image properties, e.g., occurrence of fogs, but also damage to a surface of the photosensitive member. Therefore, it is also one of important problems
REFERENCES:
patent: 3959008 (1976-05-01), Warner et al.
patent: 3988478 (1976-10-01), Wiggins
patent: 4435378 (1984-03-01), Reck et al.
patent: 5973059 (1999-10-01), Yamazaki et al.
Hisashi Hideyuki
Kuno Hiroaki
Makino Katsuaki
Matsuki Akihiro
Suda Yasuharu
Hoke Veronica P.
Mitsubishi Chemical Corporation
Mitsubishi Heavy Industries Ltd.
LandOfFree
Pigment composition for liquid toner does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pigment composition for liquid toner, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pigment composition for liquid toner will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-543092