Method of using an image forming apparatus

(19)

(11)

EP 0 973 071 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	05.07.2000 Bulletin 2000/27

(43)	Date of publication A2:
	19.01.2000 Bulletin 2000/03

(21)	Application number: 99304271.2

(22)	Date of filing: 01.06.1999

(51)	International Patent Classification (IPC)⁷: G03G 15/00, G03G 15/01, G03G 15/09

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

14.07.1998 EP 98305581

(71)	Applicant: XEIKON NV
	B-2640 Mortsel (BE)

(72)	Inventors:
	Janssens, Robert Frans Louisa 2440 Geel (BE) Van Aken, Luc Karel Maria 3511 Hasselt (BE) Waterschoot, William Constant Maria 9111 Belsele (BE)

(74)	Representative: Gambell, Derek
	D Gambell & Co, Melbury House, 34 Southborough Road Bickley, Kent BR1 2EB Bickley, Kent BR1 2EB (GB)

(54)	Method of using an image forming apparatus

(57) A plurality of electrostatic images are formed on a moving tensioned belt (26) comprising an electrically conductive base (58) having a non-conductive image-carrying surface layer (59). The images are developed by passing the belt through a plurality of toner development stations, each of which includes a development unit (35, 36, 37, 38) including a magnetic roller (51) and a backing member (53), in opposed position to the magnetic roller (51), over which the belt (26) passes. Under non-ideal conditions (defined in the text), the image quality in terms of image density and uniformity of image density and rendition of sharp image transitions, is substantially improved by using an alternating electrical field between the magnetic roller (51) and the belt (26), the peak-to-peak voltage of which is greater than 800 volts.

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