Browse Prior Art Database

DEVELOPER RELIEF VENT TO FACILITATE DEVELOPER ROLL CLEARING

IP.com Disclosure Number: IPCOM000026726D
Original Publication Date: 1993-Jun-30
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 102K

Publishing Venue

Xerox Disclosure Journal

Abstract

A developer unit 10 employed in an electrophotographic printing machine arranged to produce highlight color copies, in a single pass, is depicted in the Figure. As shown therein, developer unit 10 includes a color development housing 20 and a black development housing 22. In the highlight color printing mode, both developer housings 20 and 22 run simultaneously to facilitate development of a trilevel electrostatic image by both the color and black toners in a serial fashion. When the printing machine switches to a black executive printing mode, it is necessary to completely clear the developer rolls 24 and 26 of developer beads 60. This is required because free standing developer beads 60 on the color housing 20 will discharge the black electrostatic latent image, causing severe print quality problems. To aid roll clearing, developer rolls 24 and 26 are rotated in a reverse direction for 600 milliseconds as indicated respectively by direction arrows 21 and 23. In a similar manner, auger rolls 28,30 and 32 are rotated in the direction of arrows 31,33 and 35. This roll clearning process does not always provide a completely bead free roll, especially on developer roll 26, when considering the tolerances on the developer mass, voltage to the developer drive motor, and a tilt angle specification. Contrarily, the developer roll 26 begins to clear but is replenished with new developer beads 60 that are transported up and around housing wall 50 by mechanical forces induced by both the developer roll 26 and the auger roll 30.

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XEROX DISCLOSURE JOURNAL

DEVELOPER RELIEF VENT TO FACILITATE DEVELOPER ROLL CLEARING
Larry G. Hogestyn
Kenneth L. Timmons
Gerald T. Lioy

Proposed Classification US. C1.3551245
Int. C1. G03g 15/06

22

20

XEROX DISCLOSURB JOURNAL - Vol. 18, No. 3 May/June 1993 263

[This page contains 1 picture or other non-text object]

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DEVELOPER RELIEF VENT TO FACILITATE DEVELOPER ROLL CLEARING (Cont'd)

A developer unit 10 employed in an electrophotographic printing machine arranged to produce highlight color copies, in a single pass, is depicted in the Figure. As shown therein, developer unit 10 includes a color development housing 20 and a black development housing 22. In the highlight color printing mode, both developer housings 20 and 22 run simultaneously to facilitate development of a trilevel electrostatic image by both the color and black toners in a serial fashion. When the printing machine switches to a black executive printing mode, it is necessary to completely clear the developer rolls 24 and 26 of developer beads 60. This is required because free standing developer beads 60 on the color housing 20 will discharge the black electrostatic latent image, causing severe print quality problems. To aid roll clearing, developer rolls 24 and 26 are rotated in a reverse direction for 600
milliseconds as indicated respectively by direction arrows 21 and 23. In a similar manner, auger rolls 28,30 and 32 are rotated in the direction of arrows 31,33 and 35. This roll clea...