GB2225111A

GB2225111A - Determining printing area proportion

Info

Publication number: GB2225111A
Application number: GB8924698A
Authority: GB
Inventors: Wolfgang Arnold; Ralph Brauner; Helmut Weigend; Frank Koehler
Original assignee: Kombinat Polygraph Werner Lamberz VEB; Polygraph Leipzig Kombinat Veb
Current assignee: Kombinat Polygraph Werner Lamberz VEB; Polygraph Leipzig Kombinat Veb
Priority date: 1988-11-07
Filing date: 1989-11-02
Publication date: 1990-05-23
Also published as: GB8924698D0; JPH03140246A; CN1042509A; DD276656A1; DE3928877A1; FR2638679A1

Description

1 2225111 EQUIPMENT FOR DETERMINING PRINTING AREA PROPORTION The present

invention relates to equipment for determining print ing area proportion to enable preliminary setting of zonal ink metering in a Printing machine.

In EP-PS 0 095 606 there is disclosed a process and a device for determination of the areal coverage of a print original or printing plate for a printing machine, according to which a zonewise determin ation of the degree of areal coverage is performed by means of measuring equipment with sensors. Before the start of the measurement, each in- dividual sensor is calibrated with the aid of calibrating strips with respectively minimum and maximum areal coverage. The sensors are adapted to the conditions specific to the print original or printing plate by way of a further correction calibration using one or more sensors or an additional sensor in the measuring equipment. By this means, matching to equal values of all sensors is undertaken. This correction calibration and matching is performed within a calibration field and calibration region which are situated on-the print oriainal or Printing plate. A simpler operation and capability to reproduce the areal coverage Profile of the original is achieved. 20 At the same time, matching is possible to different Print original types and formats through automatic position recognition of the calibration strip, the calibration region and the type as well as the format of the print original or Printing plate.

However, it is disadvantageous in this method and device that the amplification of the measurement signals must be determined and adJusted anev; according to Plate type. This process depends on subJective influencing factors due to the manual activity and reduces the reliability.

2 - There is therefore a need for equipment for determination of printing areal proportion more raoidly and with greater reliability, especially by reducing subjective influencing factors and removing the the need to determine and adjust the amplifications of the measurement signals for each change of the plate type.

According to the present invention there is provided equipment for determining printing area proportion to enable preliminary setting of zonal ink metering in a printing machine, the equipment comprising a plurality of optical sensors for zone-by-zone detection of the extent of areal coverage of a print original or printing plate to be used in a printing operation by such machine, a plurality of amplifiers for amplifying measurement output signals provided by the sensors, an amplification unit connected at input means thereof to outputs of the amplifiers and having an externally controllable amplification value, the unit being connected at a control input thereof to switching means, and an analog-to-digital conve-rter connected at an input thereof to an output of the unit.

An embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawing, the single figure of which is a schematic block diagram of equipment embodying the invention.

Referring now to the drawing, there is shown equipment comprising sensors 1, 2, 3 and n which each serve for measurmert of a column having the width of an ink zone and which have respective amDlifiers connected with an amDli'.ier unit 4. The measurement signal amDlifi.cat- -side. The ion of the amplifier unit 4 can be switched over from out number of the amDlification stages that are switchable over corresponds 1 to the number of the plate types to be measured. The amplification required in correspondence with the respective Plate type is determined once and preliminarily set in the amplifier unit 4, the relevant amplification stage being switched in by way of a switching device 5.

The switching function can be performed by a computer after input of the corresponding plate type. Other switching devices 5, for example keyboards, can be used. The measurement values amplified in correspondence with the respective plate type are thereafter converted by an analog-to-digital converter 6 into digital signals and conducted to a computer for evaluation.

Claims

CLAIMS 1 Equipment for determining printing area proportion to enable

preliminary setting of zonal ink metering in a printing machine, the equipment comprising a plurality of optical sensors for zone-by-zone detection of the extent of areal coverage of a print original or printing plate to be used in a printing operation by such machine, a plurality of amplifiers for amplifying measurement output signals provided by the sensors, an amplification unit connected at input means thereof to 0UtpL'tS of the amplifiers and having an externally controllable amplification value, the unit being connected at a control input thereof to switching means, and an anal og-to-di gital converter connected at an input thereof to an output of the unit.
2. Equipment substantially as hereinbefore described with reference to the accompanying drawing.
3. A printing machine orovided with equipment as claimed in either claim 1 or claim 2.

Published 1990 at The Patent Office.State House. 6E 71 HJgl'.Hebcrr..Lcnd. .-,-.WC1 R 47F 1',irt-nc,-cpiesy.-.aybc-obtaineci from The Patent Office Saless Branch. St. 11am, Cray. Orpingt=. Ker.' ER5 3Rl- Frintei t,, Mulltip.ex t.-chrie.jec 'tJ S. 11a7; Cray. Hent. CCr. 1 V