Method and arrangement for adjustment of photographic copying apparatus

Claim 2

Arrangement for adjusting photographic copying apparatus having a first, second and third color channel for controlling, respectively, the illumination time in a first, second and third primary color, said first, second and third color channel having, respectively, a first, second and third photoreceiver, first, second and third integrator means, each connected to the output of a corresponding one of said photoreceivers, for furnishing, respectively, a first, second and third total color signal corresponding to the total quantity of illumination having impinged upon the corresponding one of said photoreceivers during said illumination time, and first, second and third terminating means for terminating the exposure in said first, second and third color channel, respectively, when the corresponding one of said total color signals is equal to a corresponding one of a first, second and third reference signal, in combination, first, second and third and fourth storage means in each of said color channels, for storing, respectively, first, second and third and fourth signals corresponding respectively to the sensitivity to the corresponding color of the copying material, the required color correction value in the corresponding color, the required density correction value, and the slope correction value, said fourth signal constituting, at least in part, a reference signal, at least one of said storage means being adjustable under predetermined operating conditions to a calibrating signal corresponding to the signal to be stored in another of said storage means during the exposure time; and null indicator means for comparing said calibrating signal to said signal in said other of said storage means and for indicating equality when the signal in said other storage means has been adjusted to equal said calibrating signal.

Claim 3

An arrangement as set forth in claim 1, wherein said first, second, third and fourth storage means comprise, respectively, a first, second, third and fourth potentiometer, the signals at the wiper arms of said first, second, third and fourth potentiometers constituting, respectively, said first, second, third and fourth signals.

Claim 4

An arrangement as set forth in claim 1, further comprising auxiliary storage means connected to said at least one storage means and said null indicator means.

Claim 5

An arrangement as set forth in claim 3, wherein said auxiliary storage means comprise an auxiliary potentiometer, the signal at the wiper arm of said auxiliary potentiometer constituting an auxiliary signal.

Claim 6

An arrangement as set forth in claim 3, wherein each of said color channels further comprises a logarithmic amplifier connected to the output of said integrator circuit means; a first summing amplifier having a first input connected to the output of said logarithmic amplifier and a second input connected to the output of said storagE means; a second summing amplifier for furnishing said reference signal; slope center storage means for storing a slope center signal corresponding to the desired slope center; sample and hold storage means having an input connected to the output of said slope center storage means and to the output of said first summing amplifier; wherein said null indicator means has a first and second contact movable simultaneously to a first and second operating position; wherein, in said first operating position, said first contact is connected to the output of said second summing amplifier means and the output of said auxiliary storage means, and in the second operating position said first contact is connected to ground potential; and wherein said second contact is connected to the output of said first summing amplifier means when in said first operating position, and to the output of said sample and hold circuit means when in said second operating position.

Claim 7

An arrangement as set forth in claim 5, further comprising first, second and third switch means for respectively connecting said first input of said first summing amplifier means, said input of said sample and hold circuit means, and the output of said fourth storage means to ground potential when closed.

Claim 8

An arrangement as set forth in claim 1, wherein said integrator circuit means each comprise an operational amplifier having an RC feedback circuit; further comprising adjustable resistance means connected in series with each of said RC circuits; and selector switch means connected in said feedback circuit of each of said operational amplifiers, for selectively short-circuiting said RC circuit or said adjustable resistance means, whereby each of said operational amplifiers serves, selectively, as integrator means or as a proportional amplifier.

Claim 9

In photographic apparatus for making color copies of originals on copying material, said copying apparatus having a first, second and third color channel for controlling, respectively, the illumination time in a corresponding one of a first, second and third primary color, said first, second and third channels having, respectively, first, second and third photoreceiver means for furnishing, respectively, a first, second and third color signal corresponding to light falling upon the photoreceiver means in the corresponding one of said colors, first, second and third integrator circuit means each connected to the output of a corresponding one of said photoreceiver means for furnishing, respectively, a first, second and third total color signal corresponding to the total quantity of illumination having fallen upon a corresponding one of said photoreceiver means during said illumination time, a plurality of correction signal storage means in each of said channels for furnishing correction signals each compensating for a determined characteristic of said originals or said copying material and applying selected ones of said correction signals to said total color signals during said illumination time, means for furnishing a first, second and third reference signal each corresponding at least in part to a selected one of said correction signals in the corresponding channel, first, second and third comparing means for comparing, respectively, said first, second and third total color signals as modified by said correction signals to said first, second and third reference signals and furnishing a first, second and third terminating signal for terminating the exposure in the corresponding one of said color channels when a predetermined relationship exists between the so-compared signals, a method for adjusting said apparatus, comprising, in combination, the steps of applying a variable calibrating signal to said apparatus under predetermined operating conditions of said apparatus; varying said variable calibrating signal until said apparatus furnishes optimum copies of a selected original, the variable calibrating signal required for said optimum copies constituting the desired cAlibrating signal; comparing said desired calibrating signal to a corresponding one of said correction signals stored in said storage means, and adjusting said correction signals stored in said storage means until the so-adjusted correction signal is equal to said desired calibrating signal.

Claim 10

In photographic apparatus for making color copies of originals on copying material, said copying apparatus having a first, second and third color channel for controlling, respectively, the illumination time in a corresponding one of a first, second and third primary color, said first, second and third channels having, respectively, first, second and third photoreceiver means for furnishing, respectively, a first, second and third color signal corresponding to light falling upon the photoreceiver means in the corresponding one of said colors, first, second and third integrator circuit means each connected to the output of a corresponding one of said photoreceiver means for furnishing, respectively, a first, second and third total color signal corresponding to the total quantity of illumination having fallen upon a corresponding one of said photoreceiver means during said illumination time, a plurality of correction signal storage means in each of said channels for furnishing correction signals each compensating for a determined characteristic of said originals or said copying material and applying selected ones of said correction signals to said total color signals during said illumination time, means for furnishing a first, second and third reference signal each corresponding at least in part to a selected one of said correction signals in the corresponding channel, first, second and third comparing means for comparing, respectively, said first, second and third total color signals as modified by said correction signals to said first, second and third reference signals and furnishing a first, second and third terminating signal for terminating the exposure in the corresponding one of said color channels when a predetermined relationship exists between the so-compared signals, a method for adjusting said apparatus, comprising, in combination, the steps of applying a variable calibrating signal to said apparatus under predetermined operating conditions of said apparatus; varying said variable calibrating signal until said apparatus furnishes optimum copies of a selected original, the variable calibrating signal required for said optimum copies constituting the desired cAlibrating signal; comparing said desired calibrating signal to a corresponding one of said correction signals stored in said storage means, and adjusting said correction signals stored in said storage means until the so-adjusted correction signal is equal to said desired calibrating signal.

Claim 11

A method as set forth in claim 8, wherein said step of comparing said desired calibrating signal to the corresponding one of said correction signals comprises comparing said desired calibrating signal to an auxiliary signal stored in an auxiliary storage and adjusting said auxiliary signal until said auxiliary signal is equal to said desired calibrating signal; switching off said desired calibrating signal; comparing said auxiliary signal to said correction signal stored in said storage means and adjusting said correction signal in said storage means until said correction signal is equal to said auxiliary signal.

Claim 12

A method as set forth in claim 9, wherein said storage means further comprise a single slope center storage for furnishing a slope center signal to said first, second and third color channels; wherein said step of applying said variable calibrating signal comprises furnishing said first, second and third color signals for a calibrating original; wherein said step of varying said variable calibrating signal comprises amplifying said first, second and third so-furnished color signals by an amplification factor adjusted in such a manner that a corresponding amplified color signal equal to the corresponding one of said total color signals at the termination of the exposure of the corresponding color is created; wherein said step of comparing comprises comparing said slope center signal simultaneously to said amplified color signals; and wherein said step of adjusting said correction signal comprises adjusting said slope center signal until said slope center signal is equal to one of said amplified color signals.

Claim 13

A method as set forth in claim 10, further comprising the step of decreasing the light impinging upon said photoreceivers in the other two of said color channels until each of said amplified color signals is equal to the so-adjusted slope center signal.

Claim 14

A method as set forth in claim 11, wherein said step of decreasing said light falling on said photoreceivers in the other two of said color channels comprises inserting complementary color filters partially into the paths of said lights.

Claim 15

A method as set forth in claim 10, wherein said correction signals comprise first correction signals corresponding to the sensitivity to the corresponding color of the copying material and second correction signals corresponding to the required slope correction value; and wherein said method of adjusting said apparatus comprises adjusting said first correction signals, said slope center signals and said slope correction signals in that order.

Claim 16

A method as set forth in claim 13, wherein said predetermined operating conditions comprise a corrected first correction signal, a corrected slope center signal, and an original selected from the originals to be reproduced; further comprising the step of furnishing a comparison signal corresponding to the brightness of said original in a selected one of said colors, as modified by said adjusted first correction signal; wherein the step of comparing comprises comparing the difference between said desired calibrating signal and said auxiliary signal to said comparison signal and adjusting the auxiliary signal until said difference is equal to said comparison signal, comparing the so-adjusted auxiliary signal to said slope correction signal, and adjusting said slope correction signal until said slope correction signal is equal to the so-adjusted auxiliary signal.