Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1992-06-25
1994-08-30
McCamish, Marion E.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
546 8, 544225, 548404, G03C 908, C07F 506, C07F 702, C07F 1100
Patent
active
053427238
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the use of biscationic acid amide derivatives and acid imide derivatives as colorless charge controllers in toners and developers for electrophotographic recording processes. Due to the controlled chemical linkage of specific acid amide groupings or acid imide groupings with two components in each case containing ammonium or phosphonium, combination of these units taking place via the particular amide nitrogens or imide nitrogens, the compounds according to the invention have particularly high and constant charge control properties, excellent heat stabilities and a very good dispersibility.
In electrophotographic recording processes, a "latent charge image" is generated on a photoconductor. This is effected, for example, by charging of a photoconductor by a corona discharge and subsequent imagewise exposure to light of the electrostatically charged surface of the photoconductor, the exposure to light causing the charge to drain to the earthed substrate at the exposed points. The "latent charge image" thus produced is then developed by application of a toner. In a subsequent step, the toner is transferred from the photoconductor to, for example, paper, textiles, films or plastic, and is fixed there, for example by pressure, radiation, heat or the action of solvents. The used photoconductor is then cleaned and is available for a new recording operation.
The optimization of toners is described in numerous patent specifications, the influence of the toner binder (variation of resin/resin components or wax/wax components), the influence of controllers or other additives or the influence of carriers (in two-component developers) and magnetic pigments (in one-component developers), inter alia, being investigated.
A measure of the toner quality is its specific charge q/m (charge per unit measure). In addition to the symbol and level of the electrostatic charge, a critical quality criterion is that the desired charge level is achieved rapidly and that this charge remains constant over a relatively long activation period. In practice, this is of central importance inasmuch as the toner may be exposed to a considerable activation time in the developer mixture before it is transferred to the photoconductor, since it sometimes remains in the developer mixture for a period for production of up to several thousand copies. The insensitivity of the toner to climatic influences, such as temperature and atmospheric humidity, is moreover another important suitability criterion.
Both positively and negatively chargeable toners are used in copiers and laser printers, depending on the type of process and apparatus.
So-called charge controllers (also called charge control agents) are often added in order to obtain electrophotographic toners or developers with either positive or negative triboelectric charging. In addition to the symbol of the charge control, the extent of the controlling effect is of importance, since a higher activity allows a small amount to be used.
Since toner binders by themselves as a rule show a marked dependence of the charging on the activation time, the object of a charge controller is on the one hand to establish the sign and level of the toner charge and on the other hand to counteract the charge drift of the toner binder and ensure a constant toner charge.
Charge controllers which cannot prevent the toner or developer from displaying a high charge drift over a prolonged use period (ageing), and which can even cause the toner or developer to undergo a charge reversal, are therefore unsuitable in practice.
Full color copiers and laser printers operate by the trichromism principle, which necessitates exact matching of the color shades of the three primary colors (yellow, cyan and magenta). The slightest shifts in color shade even of only one of the three primary colors necessarily require a shift in color shade of the other two colors so that full color copies and prints which are true to the original can also then be produced.
Because of this precise matching of the col
REFERENCES:
patent: 3893939 (1975-07-01), De Kalb et al.
patent: 4057426 (1977-11-01), Mammino et al.
patent: 4415646 (1983-11-01), Gruber et al.
patent: 4493883 (1985-01-01), Gruber et al.
patent: 4496643 (1985-01-01), Wilson et al.
patent: 4656112 (1987-04-01), Kawagishi et al.
patent: 4683188 (1987-07-01), Suzuki et al.
patent: 4684596 (1987-08-01), Bonser et al.
patent: 4927729 (1990-03-01), Harnisch et al.
Dietz Erwin
Gitzel Jorg
Macholdt Hans-Tobias
Schiebler Siegfried
Chapman Mark A.
Hoechst Aktiengesellschaft
McCamish Marion E.
LandOfFree
Biscationic acid amide and acid imide derivatives as charge cont does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Biscationic acid amide and acid imide derivatives as charge cont, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Biscationic acid amide and acid imide derivatives as charge cont will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-29135