Method and apparatus for control of the supply of ink for offset duplicating machines

Claim 3

A method as set forth in claim 1 wherein scanning of the image surface of a master plate in the step of producing read-out pulses is carried out by moving a scanning head axially of a master cylinder on which the master plate is mounted while the master cylinder is rotated.

Claim 4

A method as set forth in claim 1 wherein scanning of the image surface of a master plate in the step of producing read-out pulses is carried out by means of a scanning head while the master plate is placed on a master plate feed tray.

Claim 5

A method as set forth in claim 1 wherein automatic control of the quantity of ink in the step of automatically controlling the quantity of ink supplied to the master plate in accordance with said ratio is effected by varying the amount of angular rotation of an ink fountain roller.

Claim 6

A method as set forth in claim 4 wherein the amount of angular rotation of the ink fountain roller is varied by means of a pulse motor.

Claim 7

A method as set forth in claim 4 wherein the amount of angular rotation of the ink fountain roller is varied by means of a solenoid.

Claim 8

A method as set forth in claim 1 wherein automatic control of the quantity of ink in the step of automatically controlling the quantity of ink supplied to the master plate in accordance with said ratio is effected by varying the speed of an electric motor for driving the duplicating machine.

Claim 9

In a method of offset-printing a copy sheet with an image from a master plate, the steps of a. detecting the ratio of the area of the image to the total area of the master plate; b. producing a control signal determined by the magnitude of the value of said ratio; and c. controlling the application of ink to the copy sheet in accordance with the control signal for varying the amount of ink applied in direct relation to the value of said ratio, wherein the ratio-detecting step comprises i. scanning the master plate for producing readout pulses of duration determined by the magnitude of image areas scanned, ii. generating reference pulses of constant predetermined frequency, and iii. applying said readout pulses and reference pulses to an AND circuit for producing output pulses, of a number determined by the cumulative duration of said readout pulses; and wherein the signal-producing step comprises i. counting said output pulses, and ii. producing a control signal determined by the counted number of said output pulses.

Claim 10

In a method of offset-printing a copy sheet with an image from a master plate, the steps of a. detecting the ratio of the area of the image to the total area of the master plate; b. producing a control signal determined by the magnitude of the value of said ratio; and c. controlling the application of ink to the copy sheet in accordance with the control signal for varying the amount of ink applied in direct relation to the value of said ratio, wherein the ratio-detecting step comprises i. scanning the master plate for producing readout pulses of duration determined by the magnitude of image areas scanned, ii. generating reference pulses of constant predetermined frequency, and iii. applying said readout pulses and reference pulses to an AND circuit for producing output pulses, of a number determined by the cumulative duration of said readout pulses; and wherein the signal-producing step comprises i. counting said output pulses, and ii. producing a control signal determined by the counted number of said output pulses.

Claim 11

In a method of offset-printing a copy sheet with an image from a master plate, the steps of a. detEcting the ratio of the area of the image to the total area of the master plate; b. producing a control signal determined by the magnitude of the value of said ratio; and c. controlling the application of ink to the copy sheet in accordance with the control signal for varying the amount of ink applied in direct relation to the value of said ratio, wherein the ratio-detecting step comprises i. determining said ratio, and ii. forming, on a non-image portion of said master plate, scannable code marks representative of the determined value of said ratio; and wherein the signal-producing step comprises i. scanning said non-image portion of said master plate for detecting said code marks, and ii. producing a control signal in response to the detected presence of said code marks, and representative thereof.

Claim 12

In a method of offset-printing a copy sheet with an image from a master plate, the steps of a. detEcting the ratio of the area of the image to the total area of the master plate; b. producing a control signal determined by the magnitude of the value of said ratio; and c. controlling the application of ink to the copy sheet in accordance with the control signal for varying the amount of ink applied in direct relation to the value of said ratio, wherein the ratio-detecting step comprises i. determining said ratio, and ii. forming, on a non-image portion of said master plate, scannable code marks representative of the determined value of said ratio; and wherein the signal-producing step comprises i. scanning said non-image portion of said master plate for detecting said code marks, and ii. producing a control signal in response to the detected presence of said code marks, and representative thereof.

Claim 13

Offset printing apparatus including in combination, a. a master plate bearing an image to be printed; b. a rotary master cylinder for carrying said plate; c. means for supplying ink to said plate on said master cylinder; d. a printing couple including a blanket cylinder for transferring an inked image from said plate to a copy sheet; and e. means for rotatably driving said printing couple to advance the copy sheet therethrough; wherein the improvement comprises: f. means for movably scanning said master plate to direct the ratio of the area of the image thereon to the total area of the plate and for producing a first output signal in response to the detected ratio; g. means for controlling the application of ink to the copy sheet in response to a control signal; and h. means for converting said first signal to a control signal for said controlling means for varying the application of ink to the copy sheet in direct relation to the detected magnitude of said ratio, wherein said master plate bears, on a non-image-bearing portion thereof, code marks representative of the value of said ratio; and wherein said scanning means comprises means for scanning said non-image-bearing portion of said plate to detect said code marks and produce a first signal representative thereof.

Claim 14

Offset printing apparatus including in combination, a. a master plate bearing an image to be printed; b. a rotary master cylinder for carrying said plate; c. means for supplying ink to said plate on said master cylinder; d. a printing couple including a blanket cylinder for transferring an inked image from said plate to a copy sheet; and e. means for rotatably driving said printing couple to advance the copy sheet therethrough; wherein the improvement comprises: f. means for movably scanning said master plate to direct the ratio of the area of the image thereon to the total area of the plate and for producing a first output signal in response to the detected ratio; g. means for controlling the application of ink to the copy sheet in response to a control signal; and h. means for converting said first signal to a control signal for said controlling means for varying the application of ink to the copy sheet in direct relation to the detected magnitude of said ratio, wherein said master plate bears, on a non-image-bearing portion thereof, code marks representative of the value of said ratio; and wherein said scanning means comprises means for scanning said non-image-bearing portion of said plate to detect said code marks and produce a first signal representative thereof.

Claim 15

Apparatus as defined in claim 10, wherein said ink-application-controlling means comprises means for adjusting said ink-supplying means in response to said control signal to vary the supply of ink to said plate in direct relation to the detected value of said ratio.

Claim 16

Apparatus as defined in claim 10, wherein said ink-application-controlling means comprises means for adjusting said driving means in response to said control signal to vary the velocity at which said printing couple is driven in inverse relation to the detected value of said ratio.

Claim 17

Offset printing apparatus including, in combination, a. a master plate bearing an image to be printed; b. a rotary master cylinder for carrying said plate; c. means for supplying ink to said plate on said master cylinder; d. a printing couple including a blanket cylinder for transferring an inked image from said plate to a copy sheet; and e. means for rotatably driving said printing couple to advance the copy sheet therethrough; wherein the improvement comprises: f. means for movably scanning said master plate to detect the ratio of the area of the image thereon to the total area of the plate and for producing a first output signal in response to the detected ratio; g. means for controlling the application of ink to the copy sheet in response to a control signal; and h. means for converting said first signal to a control signal for said controlling means for varying the application of ink to the copy sheet in direct relation to the detected magnitude of said ratio, wherein said scanning means comprises means for successively scanning parallel linear portions of said plate and producing a first signal comprising a succession of readout pulses of number and duration determined by the magnitude of the area Of scanned image on said plate; and wherein said converting means comprises means for generating reference pulses of constant predetermined frequency, an AND circuit to which said readout pulses and said reference pulses are supplied for producing output pulses, at said predetermined frequency, of a number determined by the cumulative duration of said readout pulses, and means for counting said output pulses to produce a control signal representative of the counted number of said output pulses.

Claim 18

Offset printing apparatus including, in combination, a. a master plate bearing an image to be printed; b. a rotary master cylinder for carrying said plate; c. means for supplying ink to said plate on said master cylinder; d. a printing couple including a blanket cylinder for transferring an inked image from said plate to a copy sheet; and e. means for rotatably driving said printing couple to advance the copy sheet therethrough; wherein the improvement comprises: f. means for movably scanning said master plate to detect the ratio of the area of the image thereon to the total area of the plate and for producing a first output signal in response to the detected ratio; g. means for controlling the application of ink to the copy sheet in response to a control signal; and h. means for converting said first signal to a control signal for said controlling means for varying the application of ink to the copy sheet in direct relation to the detected magnitude of said ratio, wherein said scanning means comprises means for successively scanning parallel linear portions of said plate and producing a first signal comprising a succession of readout pulses of number and duration determined by the magnitude of the area Of scanned image on said plate; and wherein said converting means comprises means for generating reference pulses of constant predetermined frequency, an AND circuit to which said readout pulses and said reference pulses are supplied for producing output pulses, at said predetermined frequency, of a number determined by the cumulative duration of said readout pulses, and means for counting said output pulses to produce a control signal representative of the counted number of said output pulses.

Claim 19

Apparatus as defined in claim 13, wherein said ink-application-controlling means comprises means for adjusting said ink-supplying means in response to said control signal to vary the supply of ink to said plate in direct relation to the detected value of said ratio.

Claim 20

Apparatus as defined in claim 13, wherein said ink-application-controlling means comprises means for adjusting said driving means in response to said control signal to vary the velocity at which said printing couple is driven in inverse relation to the detected value of said ratio.

Claim 21

An offset printing device having a master plate bearing an image and a controllable ink supply for printing said image, wherein the improvement is in a device for controlling the ink supply as a function of the density of the image on the master plate, comprising: means for scanning the master plate in a succession of relatively narrow scan lines and for generating a first type read-out signal while traversing an area of the master plate which bears said image and for generating a second type read-out signal while traversing an area of the master plate which does not bear an image; means for generating a clock pulse train of transmission pulses; means for counting said transmission pulses; means connecting the scanning means, the generating means and the counting means for applying said transmission pulses to the counting means to be counted therein only while a first type read-out signal is being generated by the scanning means, whereby the count accumulated in the counting means at any particular time represents the ratio of the image area to the total scanned area up to that time; and means connecting the counting means and the ink supply for controlling the ink supply as a function of the count accumulated in the counting means.

Claim 22

An offset printing device having a master plate bearing an image and a controllable ink supply for printing said image, wherein the improvement is in a device for controlling the ink supply as a function of the density of the image on the master plate, comprising: means for scanning the master plate in a succession of relatively narrow scan lines and for generating a first type read-out signal while traversing an area of the master plate which bears said image and for generating a second type read-out signal while traversing an area of the master plate which does not bear an image; means for generating a clock pulse train of transmission pulses; means for counting said transmission pulses; means connecting the scanning means, the generating means and the counting means for applying said transmission pulses to the counting means to be counted therein only while a first type read-out signal is being generated by the scanning means, whereby the count accumulated in the counting means at any particular time represents the ratio of the image area to the total scanned area up to that time; and means connecting the counting means and the ink supply for controlling the ink supply as a function of the count accumulated in the counting means.

Claim 23

An offset printing device as in claim 16 wherein the means for controlling commences controlling the ink supply before the scanning of the master plate is completed.

Claim 24

An offset printing machine as in claim 17 wherein the controlling means include means for increasing the output of the ink supply by a preset amount each time the counting means accumulates a preset number of counts while the master plate is being scanned.

Claim 25

An offset printing device as in claim 18 wherein the controlling means include a pulse motor, means for pulsing the motor in response to the accumulation of a preset count of pulses in the counting means, and means for driving the ink supply with the pulse motor to increase the output of the ink supply with each motor pulse while the master plate is being scanned.

Claim 26

An offset printing device as in claim 16 wherein the controlling means include a solenoid connected to the ink supply and energizable to increase the output of the ink supply and means responsive to the accumulation of a preset number of pulses in the counting means to energize the solenoid.

Claim 27

An offset printing device as in claim 16 wherein the offset printing device includes a variable speed motor defining printing speed and wherein the improvement includes means for controlling the speed of the motor as a function of the count accumulated in the counting means after scanning of the master plate is completed.

Claim 28

An offset printing device as in claim 21 including means for incrementally increasing the output of the ink supply in response to defined incremental increase in the count accumulated by the counting means while the master plate is being scanned.

Claim 31

A method as in claim 23 wherein the controlling step includes controlling the ink supply while the master plate is being scanned.

Claim 32

A method as in claim 23 wherein the controlling step includes incrementally increasing the output of the ink supply upon the accumulation of a defined increment of counted transmission pulses while the master plate is being scanned.

Claim 33

A method as in claim 25 wherein the offset printing device includes a variable speed motor defining the speed of printing copies of said master plate and wherein the controlling step includes controlling the speed of the motor in accordance with the accumulated count of transmission pulses.