US 5,069,124 A · Method of operating a printing machine during start-up or run-on and optically testing a printed image

Abstract

During start-up or run-on of a printing machine, a printed image is transferred from a printing cylinder (2, 24, 34) on a control or test cylinder (5, 26, 35) which has a surface representative of the surface of a substrate (6, 25, 33) on which printing, later on, is to be effected, for example a white ceramic surface of roughness comparable to that of paper. The image transferred on the control or test cylinder is optically tested while the cylinder rotates over a first partial circumferential range (7, 27, 36), and data derived, either by human observation or by electro-optical sensors (8, 28, 37) to permit readjustment of operating systems of the printing machine in accordance with desired operating parameters, such as register, inking density, ink/damping fluid relationship in offset processes or the like. The printed image is then erased, extinguished or removed, for example by cleaning, by a cleaning apparatus (13, 30, 39) located in a second subsequent range (12, 29, 38) of the circumference of the control or test cylinder. Ink stripped off the control or test cylinder is recycled, and washing fluid and ink are separated, for separate recycling. When appropriate printing is obtained on the control or test cylinder (5, 26, 35), substrates can then be passed through the printing machine and printing carried out without prior scrap test prints. The method and system are suitable for all printing methods, but are preferably and primarily used in offset printing systems and methods.

Claims20

Dependent claims

Method of operating a printing machine during start-up or run-on and to eliminate printing of scrap products while adjusting the machine, wherein the printing machine has a printing cylinder (2, 24, 34) positioned for printing information on a substrate (6, 25, 33) during a printing run,

comprising the steps of
preliminarily, and in advance of the printing run by the printing machine, transferring information to be printed from the printing cylinder (2, 24, 34) onto a control or test cylinder (5, 26, 35) to form an image thereof on the control or test cylinder,
wherein said printing cylinder and said control or test cylinder are in printing engagement at a cylinder contact line;
optically testing, at a first partial circumferential range (7, 27, 36) subsequent to the cylinder contact line of the control or test cylinder, the image transferred from the printing cylinder onto said control or test cylinder, and deriving information from the printed image on said control or test cylinder within said range relative to print quality parameters;
removing the image transferred from the printing cylinder onto said control or test cylinder at a selected partial circumferential range (12, 29, 38) subsequent to said first partial circumferential range;
and
printing from said printing cylinder on the substrate after said testing step and during the printing run.

4 more elements

In combination with a printing machine which prints information on a substrate (6, 25, 33) to be printed and having a substrate surface, apparatus to reduce or eliminate printing of scrap substrate products while adjusting the machine during start-up or run-on of a printing run,

wherein the printing machine includes a printing cylinder (2, 24, 34) for transferring the printed information onto the substrate (6, 25, 33) to be printed during a printing run,
said apparatus further comprising, in accordance with the invention,
a control or test cylinder (5, 26, 35) having a surface which is an analog of the surface of the substrate to be printed,
said control or test cylinder being engageable against the printing cylinder without an intervening substrate preliminarily and in advance of the printing run of the printing machine so that the printed image is first, preliminarily, transferred from the printing cylinder onto the control or test cylinder, to permit observation of the transfer of the printed information onto the control or test cylinder over a first partial circumferential range (7, 27, 36) and to derive information therefrom relating to adjustment of operating parameters controlling operating conditions of the printing machine affecting printing quality based on adjustment of operating devices of the printing machine;
and
an erasing or extinguishing means (13, 30, 39) engageable against said control or test cylinder (5, 26, 35) for erasing the printed image preliminarily transferred thereto from the printing cylinder, and to permit, still preliminarily, transfer onto said control or test cylinder of a subsequent preliminary printed image.

3 more elements

Dependencies are inferred from the claim text.

Method of operating a printing machine during start-up or run-on and optically testing a printed image

Life of this patent

Method of operating a printing machine during start-up or run-on and optically testing a printed image

Life of this patent

Abstract

Claims20