Browse Prior Art Database

CERAMIC DICOROTRON ENDBLOCKS

IP.com Disclosure Number: IPCOM000024071D
Original Publication Date: 1979-Aug-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 357K

Publishing Venue

Xerox Disclosure Journal

Abstract

Dicorotron devices have been used to perform negative charging functions in an electrophotographic environment. A corona wire is coated with a dielectric material and excited by an AC voltage capacitively coupled to the air across the dielectric sheath. A net DC current to the surface to be charged is obtained by applying a DC bias to the surrounding corona shield.

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

      IC DICO ROTRON ENDBL OCKS Jean Laing
Judy Nagel

2/J~2Q

Proposed Classification U~S,Cl. 355/3 CH
mt. Cl. G03g 15/00

/7

P16/c

/5

P16/c

P16/b

( /4

Dicorotron devices have been used to perform negative charging functions in an electrophotographic environment. A corona wire is coated with a dielectric material and excited by an AC voltage capacitively coupled to the air across the dielectric sheath. A net DC current to the surface to be charged is obtained by applying a DC bias to the surrounding corona shield.

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Page 2 of 2

CERAMIC DICOROTRON ENDBLOCKS (Cont~d)

Present endblock designs present two main problems. The corona wire and shield are mounted within a dielectric endblock. The wire is connected to a screw which, in turn, forms the electrical connection to the shield, A serious potential for arcing from the wire-screw connection to the shield is present because of the high operating voltages required with dicorotrons. The dielectric endblock material is also prone to failure due to the high voltage burning through the block from the bottom of screw to the shield.

An improved endblock design is shown in Figure 1. In this design, endblock 12 is made from a high dielectric strength, machinable, ceramic material. End 13 goes toward the center of the shield (not shown) and end 14 to the outside. Two grooves 15 are machined into the block to match the shield dimensions and are l~deep into the block. The block and shield are held together by three screws 16 (one screw on the opposite side and not shown) as in the conventional double shield endblock. A groove 17 is milled in which to lay the dicorotron wire. A countersunk screw 18 holds the wire in position. On the co...