FR2597792A1 - METHOD FOR PRIOR ADJUSTMENT OF THE DIFFERENT ZONES OF PRINTING MACHINE INK MECHANISMS - Google Patents

Abstract

THE INVENTION CONCERNS A PROCESS FOR PRIOR ADJUSTMENT OF THE DIFFERENT ZONES OF THE INK MECHANISMS OF PRINTING MACHINES. ACCORDING TO THIS PROCEDURE, A TELEVISION CAMERA 4 SHOWS A GRAY VALUE RESOLUTION OF AT LEAST 32 STEPS FOR EACH IMAGE POINT. THE SCANNED IMAGE IS SCAN, THEN DIRECTED TO A COMPUTER 7 AND TO A VIEW SCREEN. THE WIDTH AND NUMBER OF INK ZONES CAN BE ADJUSTED ON THE COMPUTER 7. THE LIMITS OF INK ZONES ARE MATERIALIZED ON THE SCREEN, THE GRAY VALUES STORED IN MEMORY 5, 6 OF THE COMPUTER 7 BEING CORRECTED, THEN ADDITIONED BY ZONES. APPLICATION TO THE PRE-SETTING OF PRINTING MACHINES.

Description

The present invention relates to a method for pre-settling

  the different areas of the inking mechanisms of printing machines, by optical scanning of an illuminated original which, when it is transparent, is placed on a glass plate and illuminated from one side (for example a printing plate , a print film or a printed copy), by means of an ink density measuring apparatus in the form of a television camera, and by means of a presetting, controlled in a an image interpretation system via a computer, from the stored image data, the various adjustment screws of the colorimeter zones or, respectively, the other adjustment elements of the ink quantity of the The aforementioned original can be constituted, for example, by the printing plate, the printing film or a completed printing copy (or proof

  of printing) which has already been printed previously.

  Such pre-adjustment is desirable so that the inking mechanisms are correctly adjusted accurately from the beginning of printing, or so that only later adjustments are necessary.

very modest.

  For the optical scanning of the original illuminated by incidence or from one side to the other, it is known to use a television camera having a gray value resolution of at least eight steps for each image point, camera to which associated computer control and coordinate memory; the storage area defining the original may be previously selected in the coordinate memory, while the addresses of the stored values to be summed each time to generate the average values of areas may be selected by the computer in the area freed from the coordinate memory in a manner corresponding to the number and the width of the considered areas, the stored values being summed. In this

  device, the printed sheet of paper is measured,

2597792 '

  These elements are successively printed on different color filters in front of the camera. As a result, the amount of ink actually deposited by printing is not detected because individual inks are partially covered by successive printing inks. The object of the invention is to provide a method of prior adjustment, by optical scanning, of the different areas of the printing machine inking mechanisms, which

  not be affected by the aforementioned drawbacks.

  According to the invention, this object is achieved by the fact that the television camera has a resolution of gray value of at least 32 steps for each image point, the scanned image being digitized to be subsequently directed, d on the one hand, to an interpretation calculator 15 (microcomputer) for calculating the preliminary adjustment points of the adjustment screws of the zones and, on the other hand, to a display screen, the width and the number of Inking zones that can be adjusted at will on the interpretation computer, while the limits of the inking zones are materialized, on the display screen, by light or dark lines. The gray values stored in the memory of the interpretation calculator are corrected for each image point by means of characteristic curves, then added by zones. The 25 characteristic curves are formed thanks to originals

  calibration, to be stored later.

  In the method according to the invention, the observer of the display screen is able to subsequently correct the intensity of the illumination and, if necessary, to observe and eliminate fouling of the screen. respective surface of the plate or film, or even an original of another type. Again, the width and number of zones

  inking can be chosen freely.

  The sum values of the individual zones are judiciously normed (0-100%). For this purpose, a characteristic curve is calculated through a field

reference measures.

  In another embodiment of the invention, the individual values of the inking areas are stored on a digital cassette, which is adapted to the data format of the main control of the printing mechanism. Through a display screen, the user enters the identification of the ink to be printed by the original, so that the remote control can then automatically select the mechanism.

  correct inking to perform the pre-setting.

  Compared to optical methods involving photoelectric cells and measurement of reflected light, the method according to the invention has the advantage of not causing errors in measured values resulting from the depth of field due to non-resting originals. not flat. For each image point, it is possible to automatically determine and store calibration values, which counterbalance both the uneven distribution of light and the irregular aging of the sensors.

  individual light in the camera. These standard values are not introduced temporarily into a memory.

  A very simple control of the measuring device is possible by a comparison between the original and the image reproduced on the display screen. The apparatus used in the process according to the invention can be adapted to any width and number of inking areas. The measured values are retransmitted to the desks of the printing machine in a simple and tolerant way

errors.

  The invention will now be described in more detail by way of non-limiting examples, with reference to the attached schematic drawings showing an installation for carrying out the method according to the invention, and to the following: FIGS. 2 are global representations of the installation; Figure 3 is a block diagram of this installation; and

  Fig. 4 is a plan view of a print proof for an ink.

  Figures 1 and 2 illustrate an original 1 printing, deposited on a support plate 2 of glass. More than 3 lamps are provided to illuminate this original as uniformly as possible; in the case of transparent originals, such as printing films, a lighting through is effected by means of a through-lighting device. The luminous intensity of the lamps 3 or the device 8 can be judiciously modified. The scanning of the original 1 takes place via a television camera 4 having a gray value resolution of at least 32 steps for each image point. The reference designates an apparatus for capturing and storing the image generated by the camera 4. References 6 and 7 denote, respectively, a floppy disk memory and a microcomputer equipped with a programming keyboard. The index 9 relates to a display screen for reproducing the original and delivering values. Reference numeral 10 denotes a cassette scrolling mechanism for transmitting data to the remote control console (not shown), indicating a tape printer. The microcomputer 7 presents a standardized operating system

CPM type.

  The block diagram of Figure 3 illustrates the mutual binding of the individual groups. The television camera 4 serves to receive the image of the original and the apparatus 5 serves to capture this image and to store the digitized image in at least 32 steps of gray. The display screen 9 serves to represent the image observed by the camera 4, and it comprises a location of the individual interpreted areas. The microcomputer 7 serves to interpret the image and to input or output the data, while the floppy disk memory 6 is intended for the non-specific storage of specific instructions, measurement results and calibration data. The scroll mechanism 10

  cassettes (cassette recorder) is used to memorize

  intermediate measurement results and transfer to the control device of the printing machine, in particular the inking mechanism or mechanisms. The tape printer is used to deliver measurement results for storing or, respectively, pre-adjusting printing machines without a cassette scrolling mechanism. Reference numeral 12 relates to an omnibus calculation conductor, that is to say the joining system of the individual functional blocks. The numeral 3 here indicates the lighting device 10, in the form of the lamps and / or the through-lighting device, also designated by

  the respective references 3 and 8 in FIG.

  As is evident from FIG. 4, the original 1 comprises a calibration mark 13 which, more precisely, corresponds to a field with 100 ° C. of coverage for the prior adjustment of the amplification by the camera,

  to achieve an optimal result. Reference 14 denotes a pixel, i.e., an image point of the television camera 4 measuring about 2 mm x 2 mm.

  In addition, the following measures are used: yp size of the original or printing plate 1 in the peripheral direction of the cylinder x dimension of the original or printing plate 1 in the axial direction of the cylinder yz dimension of the zone in the axial direction of the cylinder (or length of zone) x dimension of the zone in the peripheral direction of the cylinder (or zone width) yA position of the zones in the peripheral direction of the cylinder xA position of the zones in the axial direction of the cylinder

maximum number of zones.

  All of these values can be entered into the computer microphone via a keyboard, and adjusted.

  It goes without saying that many modifications can be made to the process described and shown, without leaving

of the scope of the invention.

Claims (4)

  1. A method of pre-adjusting the different areas of the printing machine inking mechanisms, by optical scanning of an illuminated original which, when transparent, is placed on a glass plate and is illuminated from one side to the other ( for example a printing plate, a printing film or a printed proof) by means of an ink density measuring apparatus in the form of a television camera, and with the aid of presetting, controlled in an image interpretation system via a computer, from the stored image data, the various adjustment screws of the zones of the colorimeter or, respectively, of the other adjustment elements the method of the invention characterized in that the television camera (4) has a gray value resolution of at least 32 steps for each image point, the scanned image being digitized to be it is then directed, on the one hand, towards a microcomputer (7) for the purpose of calculating the preliminary adjustment points 20 of the adjustment screws of the zones and, on the other hand, towards a display screen (9), the width ( xz) and the number of inking zones that can be adjusted at will on the microcomputer (7), while the limits of the inking zones are shown on the display screen (9) by clear lines or dark, and that the gray values stored in the memory (5,6) of the microcomputer (7) are corrected   through characteristic curves, then added by zones.   2. Method according to claim 1, characterized in that the sums are normalized (from 0 to 100 S).   3. Method according to claim 1 or 2, characterized in that the individual values of the inking zones   are stored on a digital cassette (10), then delivered to a printer (11).   4. Method according to any one of the claims   1 to 3, characterized in that the user enters, via a display screen (9), an identification which is associated with the printing plate used. for the ink in question.