EP 0018742 A1 19801112 - Method of improving maximum density and tonal range of electrographic images and an electrographic copying apparatus using the method.
Title (en)
Method of improving maximum density and tonal range of electrographic images and an electrographic copying apparatus using the method.
Title (de)
Verfahren zur Verbesserung der maximalen Dichte und des Tonumfangs elektrographischer Bilder und elektrographisches Kopiergerät zur Durchführung des Verfahrens.
Title (fr)
Procédé pour améliorer la densité maximale et l'étendue de variations des tons d'images électrographiques et copieur électrographique employant ce procédé.
Publication
Application
Priority
US 3066879 A 19790416
Abstract (en)
The image quality obtainable by an electrographic copying process in which an electrostatic latent image formed by imagewise exposure of a uniformly charged photoconductive layer, or otherwise, is developed with a toner can be improved if the latent image comprises discrete charge bearing zones, preferably formed by a supplementary exposure through a half-tone screen, and if additionally the toner is electrically conductive either intrinsically or as a result of electrical break-down. In this manner, the maximum density obtainable in a copy can be increased and the contrast decreased sufficiently to allow good reproduction of both continuous tone and high contrast images.
IPC 1-7
IPC 8 full level
G03G 5/14 (2006.01); G03G 13/08 (2006.01); G03G 15/04 (2006.01); G03G 15/05 (2006.01); G03G 15/09 (2006.01); G03G 15/22 (2006.01)
CPC (source: EP)
G03G 15/04027 (2013.01)
Citation (search report)
- US 3681071 A 19720801 - DONALD PHILIP JOSEPH
- US 4076857 A 19780228 - KASPER GEORGE PHILIP, et al
- US 4083632 A 19780411 - MAILLOUX LOUIS D, et al
- US 3627526 A 19711214 - DONALD PHILIP JOSEPH
- US 3341326 A 19670912 - CHRISTOPHER SNELLING
- US 3335003 A 19670808 - CHRISTOPHER SNELLING
Designated contracting state (EPC)
AT BE CH DE FR GB IT NL SE
DOCDB simple family (publication)
EP 0018742 A1 19801112; EP 0018742 B1 19830810; EP 0018742 B2 19880824; AT E4435 T1 19830815; AU 536674 B2 19840517; AU 5751880 A 19801023; BR 8002337 A 19801202; DE 3014449 A1 19801030; DE 3014449 C2 19860327; DE 3064518 D1 19830915; FR 2454646 A1 19801114; FR 2454646 B1 19831209; JP H0210954 B2 19900312; JP S5619067 A 19810223
DOCDB simple family (application)
EP 80301189 A 19800415; AT 80301189 T 19800415; AU 5751880 A 19800416; BR 8002337 A 19800415; DE 3014449 A 19800415; DE 3064518 T 19800415; FR 8008381 A 19800415; JP 4924380 A 19800416