Electrophotographic copying apparatus for the production of multiple copies from a single latent electrostatic image

Claim 2

In an electrophotographic copying apparatus of the type having at least latent electrostatic image formation means for forming a latent electrostatic image by charging a photoconductor and exposing said photoconductor to an image of an original; development means for developing an electrostatic image with a developer; image transfer means for transferring a developed image to a recording medium; and cleaning means for cleaning said photoconductor; wherein a plurality of copies can be made from the same electrostatic image formed by said latent electrostatic image formation means, the improvement comprising: first means for setting selectively the number of copies to be obtained from the same latent image, wherein a maximum number of copies is practically obtainable from the same latent image; second means for setting selectively the number of copies to be obtained from the same original; first control means for making said latent electrostatic image formation means inoperative during the period of time following the formation of the first copy until the formation of the final copy from the same latent image as set by said first means; and second control means for actuating said cleaning means when the final copy from the same latent image is formed as set by said first means and when the number of copies set by said second means have been are obtained from the same original.

Claim 3

An apparatus as in claim 1 wherein said first and second means comprise means for counting the number of copies made.

Claim 4

An apparatus as in claim 1 wherein said second control means comprises means for generating an operational signal when the number of copies made equals the number of copies set by said first means.

Claim 5

An apparatus as in claim 1 wherein said second control means comprises means for generating an operational signal when the number of copies made equals the number of copies set by said second means.

Claim 6

An apparatus as in claim 1 wherein said image transfer means comprises: a conductive belt having an insulating layer thereon; charging means for charging uniformly the insulated surface of said belt; and quenching charger means for removing electric charges on the surface of said belt.

Claim 7

In an electrophotographic copying apparatus of the type having at least latent electrostatic image formation means for forming a latent electrostatic image by charging a photoconductor and exposing said photoconductor to an image of an original; development means for developing the latent electrostatic image with a developer; image transfer means for transferring a developed image to a recording medium; and cleaning means for cleaning said photoconductor; wherein a plurality of copies can be made from the same latent electrostatic image formed by said latent electrostatic image formation means, the improvement comprising: first means for setting selectively a maximum number of copies N M to be obtained from the same latent image within a number of copies practically obtainable from the same latent image, and producing a signal in accordance therewith; second means for setting selectively the total number of copies N p to be obtained from the same original and producing a signal in accordance therewith; first regulating means for making both said cleaning means and said latent electrostatic image formation means inoperative during the period of time from the formation of the first copy to the formation of the final copy from the same latent image in response to said signals produced by said first and second means and for generating an operational signal at the formation of the final copy from the same latent image; and second regulating means for actuating at least said cleaning means and said latent electrostatic image formation means, in response to each of said operational signals from said first regulating means, until the number of copies set by said second means are obtained from the original.

Claim 8

In an electrophotographic copying apparatus of the type having at least latent electrostatic image formation means for forming a latent electrostatic image by charging a photoconductor and exposing said photoconductor to an image of an original; development means for developing the latent electrostatic image with a developer; image transfer means for transferring a developed image to a recording medium; and cleaning means for cleaning said photoconductor; wherein a plurality of copies can be made from the same latent electrostatic image formed by said latent electrostatic image formation means, the improvement comprising: first means for setting selectively a maximum number of copies N M to be obtained from the same latent image within a number of copies practically obtainable from the same latent image, and producing a signal in accordance therewith; second means for setting selectively the total number of copies N p to be obtained from the same original and producing a signal in accordance therewith; first regulating means for making both said cleaning means and said latent electrostatic image formation means inoperative during the period of time from the formation of the first copy to the formation of the final copy from the same latent image in response to said signals produced by said first and second means and for generating an operational signal at the formation of the final copy from the same latent image; and second regulating means for actuating at least said cleaning means and said latent electrostatic image formation means, in response to each of said operational signals from said first regulating means, until the number of copies set by said second means are obtained from the original.

Claim 9

An apparatus as in claim 6 wherein said first regulating means comprises: means for controlling the timing of the production of said operational signals; and comparator means for generating a control signal after comparison of said signals produced by said first and second means, which control signal actuates said controlling means such that the number of repeated uses of respective latent electrostatic images becomes approximately equal.

Claim 10

An apparatus as in claim 7 wherein said first regulating means further comprises means for generating an indicative signal upon the formation of the final electrostatic image to be obtained from a respective original to indicate the time for exchanging the original.

Claim 11

An apparatus as in claim 6 wherein said first regulating means comprises: means for evaluating N M ≧N p ? and producing a positive or negative output; and exposure start signal producing means for generating a signal to actuate said latent electrostatic image formation means in response to a positive signal from said evaluating means.

Claim 12

An apparatus as in claim 9 wherein said first regulating means further comprises: operation circuit means for evaluating N p /N M in response to a negative signal from said evaluating means; and means for evaluating b=0?, where b is zero or a positive integer in the relationship N p =a·N M +b and where a is also a positive integer, in response to an output from said N p /N M evaluating operation circuit means and for providing a signal to said exposure start signal producing means when b=0.

Claim 13

An apparatus as in claim 10 wherein said first regulating means further comprises computing circuit means, responsive to a signal from said b=0? evaluating means when b≠0, for evaluating N p =N EX ·(A)i+N EX (B)j, where N EX (A)=N p /(n EX +1), N EX (B)=N p /(n EX +1)+1 and i+j=a+1 are integers equal to or greater than zero, and n EX is the number of additional latent electrostatic images produced in addition to the original electrostatic image, and providing a signal to said exposure start signal producing means in accordance therewith.

Claim 14

Apparatus as in claim 11 wherein said first regulating means further comprises agreement and judgement circuit means for receiving said signals provided by said b=0? evaluating means and said computing circuit means and comparing these signals with the number of signals produced by said exposure start signal means and producing an indicative signal when said latter signals equal either of said former signals.

Claim 15

An apparatus as in claim 12 further comprising control means responsive to said indicative signal from said agreement and judgement circuit means for producing an output indicative of the formation of the last electrostatic image from the same original.

Claim 16

An apparatus as in claim 13 further comprising means responsive to the output from said control means for exchanging originals.

Claim 17

An apparatus as in claim 6 wherein said second means comprises means for counting the number of copies made and producing a stop signal when the number made equals N p .