Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1982-11-19
1985-03-26
Kittle, John E.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
430116, G03G 912
Patent
active
045073775
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to self-fixing liquid electrostatic image developers comprising as a dispersed component, a compatible blend of at least one polyester binder and at least one polyester plasticizer, to images formed from such developers, and to methods of forming images with such developers.
Electrographic imaging and development processes have been extensively described in both the patent and other literature. Generally, these processes having common the steps of forming an electrostatic charge image, often called an electrostatic latent image, on an insulating surface, such as a photoconductive insulating layer coated on a conductive support. The electrostatic latent image is then rendered visible by a development step in which the charge image-bearing surface is brought into contact with a suitable electrostatic image developer composition which deposits toner particles on either the charged or uncharged image areas. After development, the visible image is either heat-fixed directly to the electrostatic charge-bearing surface or it is transferred to another surface such as paper where it is there heat-fixed.
Liquid developer compositions of the type described in U.S. Pat. No. 4,202,785 are very useful for developing latent electrostatic images. These developers comprise stable dispersion of dispersed components and dissolved components in an electrically insulating carrier liquid. The dispersed components include charged particles, known as toner particles, comprising a colorant or pigment, such as carbon black, generally associated with a thermoplastic resin binder. The dissolved components include optional organic liquids from previous steps in the preparation of the liquid developer, as well as optional charge control agents.
Liquid developers containing polyester resin binders such as those disclosed in the aforementioned U.S. Pat. No. 4,202,785 as well as developers containing other polyester resin binders are particularly useful. As noted in the said U.S. patent, however, the polyesters are fixed to receiving surfaces by the application of heat. Heat-flexible polyesters having very high glass transition temperatures (T.sub.g), (i.e., above 150.degree. C.) thus require higher fixing temperatures as well as careful selection of the receiving support to avoid support distortion or charring.
In the published patent literature, various liquid toner formulations having self-fixing qualities are reported. For example, U.S. Pat. No. 3,954,640 reports the use of low T.sub.g linear addition polymers to give liquid developers and inks that become fixed to a substrate with little or no carrier evaporation in the absence of heat. It is essential to this patent that the polymer T.sub.g be no higher than 35.degree. C. The patent further discloses the use of monomeric plasticizers as optional components that are miscible in the carrier. The purpose of the plasticizer is to adjust the ability of the carrier to disperse the polymer resin.
U.K. Pat. No. 1,110,225 describes a liquid developer which is said to be self-fixing upon removal of the carrier liquid following deposition of the toner particles. To achieve such self-fixing, the patent discloses the use of liquid alkyd resins which, because of their unsaturated chemical bond linkages, cure in air upon removal of the carrier liquid. Toner particles containing oxidizing type unsaturated alkyd resins in combination with certain phenol modified pentaerythritol ester resins are also noted in U.K. Pat. No. 897,903.
Also from the patent literature, the use of certain plasticizers is reported in liquid toner formulations for purposes entirely unrelated to self-fixing. Thus, for example it is reported that toner adhesion to a substrate can be achieved by tack modification. That is, through the addition of modifying agents, a resin binder can be rendered suitably tacky to adhere to a surface of choice. According to U.S. Pat. No. 3,939,085 the addition of monomeric plasticizers to toner resins produces a toner composition that has low adhesion for an image-fo
REFERENCES:
patent: 3939085 (1973-05-01), Smith et al.
patent: 3954640 (1973-06-01), Webster et al.
patent: 4052325 (1977-10-01), Sawtilli
patent: 4202785 (1978-05-01), Merrill et al.
Dahl Torger N.
Eastman Kodak Company
Goodrow John L.
Kittle John E.
LandOfFree
Self-fixing liquid electrographic developers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-fixing liquid electrographic developers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-fixing liquid electrographic developers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1294259