Patch generator for an electrophotographic device

Claim 2

A patch generator for creating a test patch on a charged photoconductor member useful in controlling process parameters in electrophotographic machines having a main illumination source for exposing an original document; said patch generator comprising: means for producing an electrical signal having a value representative of the amount of exposure of the original document; means for modifying said signal by a selectable factor; and means, responsive to said modified signal, for producing a test patch exposure on the photoconductive member, said test patch exposure having an exposure value determined by the value of said modified signal.

Claim 3

A patch generator as set forth in claim 1 wherein said signal-producing means includes light-integrating means, exposed to the main illumination source of the electrophotographic machine, for producing a signal with a value variable with the original document exposure.

Claim 4

A patch generator as set forth in claim 2 wherein said patch-producing means comprises light-emitting means to which the photoconductor member is exposed.

Claim 5

A patch generator as set forth in claim 3 wherein said light-integrating means is exposed also to said light-emitting means.

Claim 6

A patch generator as set forth in claim 3 wherein said patch-producing means comprises means for comparing the exposure of said light-integrating means by said light-emitting means to the exposure of said light-integrating means by the main illumination source, and for terminating exposure by said light-emitting means when the two are of a predetermined ratio.

Claim 7

A patch generator for creating a test patch on a charged photoconductor member useful in controlling process parameters in electrophotographic machines having (1) a main exposure illumination source for exposing an original document and (2) operator-initiated means for changing exposure settings; said patch generator comprising: light-integrating means for producing an electrical signal having a value representative of the amount of original document exposure as controlled by the exposure setting; means responsive to the operator-initiated exposure setting for modifying said signal by a compensating factor selectable in accordance with the exposure setting to produce a modified signal which is substantially unaffected by the exposure setting; and means, responsive to said modified signal for producing a test patch on the photoconductor member, said test patch having an exposure value determined by the value of said modified signal, whereby said patch exposure is substantially unaffected by the exposure setting.

Claim 8

A patch generator for creating a test patch on a charged photoconductor member useful in controlling process parameters in electrophotographic machines having (1) a main exposure illumination source for exposing an original document and (2) operator-initiated means for changing exposure settings; said patch generator comprising: light-integrating means for producing an electrical signal having a value representative of the amount of original document exposure as controlled by the exposure setting; means responsive to the operator-initiated exposure setting for modifying said signal by a compensating factor selectable in accordance with the exposure setting to produce a modified signal which is substantially unaffected by the exposure setting; and means, responsive to said modified signal for producing a test patch on the photoconductor member, said test patch having an exposure value determined by the value of said modified signal, whereby said patch exposure is substantially unaffected by the exposure setting.