Abstract: Method and apparatus for scanning an ink test strip printed on a sheet, the sheet being positioned on a table traversed in two directions by a scanning head. The table includes guide means including a bar for positioning the sheet in a first dimension and an index mark for positioning the sheet and its associated test strip in a second dimension. The scanning head indexes to the index mark which physically establishes a first coordinate for the test strip. Thereupon, the scanning head indexes in a second direction to automatically locate the test strip based on the size of the test strip as sensed by the densitometric sensing device associated with the scanning head. Having located the second coordinate Y.sub.s for the initial test patch of the test strip, the system then initiates the scan along the test strip to measure the optical density of each test patch relating to each printed zone on the sheet.

Abstract: A light-emitting diode is used both for receiving data from an operator to change the logic state of a device and for displaying the entered data back to the operator. Current is selectively applied to the diode to display the data, but on an alternate basis the photo-current produced in the light-emitting diode by surrounding illumination is sensed and the data are received by detecting the fall-off in the photo-current caused by the operator covering the light-emitting diode. This technique is advantageously employed for the input and display of ink slide settings for a rotary printing machine by using a light-emitting diode matrix or bar graph display subject to finger-tip control by the operator. The diode matrix is scanned by repetitively and sequentially inhibiting the lighting current to the individual light-emitting diodes so that they may be sequentially connected to a photo-current monitoring circuit via a multiplexer under control of a clock circuit.

Abstract: An apparatus to obtain ink density data by scanning color measurement strips on a printed sheet has a densitometer mounted on a digitally-driven X,Y positioning mechanism, an optical sensor for detecting the position and orientation of the sheet with respect to the X,Y positioning mechanism, and a numerical computer for transforming the sheet coordinates of the color measurement strips to the X,Y coordinates of the X,Y positioning mechanism. Thus, the numerical computer can automatically position the densitometer to scan the color measurement strips. In a first embodiment, optical sensor arrays determine the position and orientation of the test sheet with respect to the X,Y positioning mechanism. In a second embodiment, the densitometer itself scans the edge portions of the test sheet to determine the position and orientation of the test sheet.

Abstract: An apparatus for determining the position of a sheet when the sheet is placed on a support having at least two spaced apart CCD linear image sensors recessed in the sheet support and partially covered by the edge portions of the sheet. The CCDs operate as line cameras, and are scanned to generate signals correlated with the points of intersection of the sheet edges and the axes of the image sensors. Preferably the apparatus has circuitry for storing calibration values of the CCD signals obtained when the image sensors are not covered by the sheet, circuitry for storing corresponding scanning signal values when the image sensors are covered by the sheet, circuitry for comparing corresponding calibration and scanning values for obtaining difference values, and circuitry for detecting maxima in the gradient of the difference values for adjacent image points to find the locations of the points of intersection of the sheet edges and the axes of image sensors.

Abstract: An automatic ink feed control for a printing machine. Several ink-dosing elements are arranged across the width of the printing machine for dosing the application of ink to a printing plate, and these ink-dosing elements are individually adjustable by an adjusting device. The ink density of several control areas on the printed material is measured by a scanning measuring device, and a computer control compares these measured ink densities to desired ink densities in order to effect control of the adjustment of the ink-dosing elements by the adjusting device.

Abstract: An ink metering system for a printing press for metering ink to individual column positions on a printing plate in which the fountain blade is formed in individual sections having power actuators to establish film-forming gaps at corresponding positions. Linear follow-up potentiometers are provided having their slides respectively coupled to the blade sections so that when the potentiometers are connected to a source of reference voltage, and the sections initially adjusted, the slider voltage provides a direct indication of the width of the gap. To change the setting over the entire width of the blade, a variable voltage supply is provided with a control for shifting the voltage from reference level to a calibrated level of offset voltage, on one side or the other of the reference, to bring about a percentage change in voltage at each of the adjustable blade sections.

Abstract: A control system for a reversible screwing tool for tightening and loosening screws in a printing press or the like which includes a pair of angularly spaced pick-up devices coupled to the shaft of the tool for generating respective series of impulses. Monostable pulse generators are coupled to the respective pick-up devices, the generator coupled to the pick-up device in leading position, for counterclockwise rotation, being set to produce an output pulse which is substantially wider than that produced by the generator which is connected to the pick-up device in trailing position so that during counterclockwise rotation the output pulses from the generators timingly overlap one another. The generators feed into the input terminals of an AND gate which is, in turn, connected to a counter which counts the pulses resulting from counterclockwise rotation of the shaft.

Abstract: A device for measuring ink film thickness in the inking system of a printing press which includes a pair of hollow transparent rollers, at least one of which is resilient so that when the rollers are in rolling engagement with one another and with an ink-carrying roller in the press, there is a longitudinally extending ribbon-like area of engagement between them through which an enclosed film of ink is fed in a thickness which varies in accordance with the thickness of the ink film in the press. A longitudinally extensive light projector in one of the rollers cooperates with a correspondingly dimensioned light collector in the other, the collector being coupled to a photocell having an output indicator. The projector and collector are both in the form of optical cross section transformers, the projector being coupled fiber-optically to an external light source. A filter assembly is interposed in the light path manually switchable for application, to the film, of light of complementary color.

Abstract: A system for facilitating throw-off and re-engagement of a blanket cylinder with respect to cooperating plate and impression cylinders and which minimizes wastage of copies incident to reestablishing equilibrium in the inking and dampening systems following an interruption of the normal printing process. Two separate control means are provided for controlling the rate of water flow, the first being an automatic control at the water fountain and the second being in the form of means for controllably disengaging the water form roller from the printing plate. Means are provided for switching from the first control means to the second when the blanket is disengaged for promptly cutting off the flow and thereafter maintaining a water film of predetermined thickness on the plate.