Man Roland Druckmaschinen Ag

Man Roland Druckmaschinen

Joachim Muller

Peter Schramm

Horst Klingler

Rolf Braun

Alfred Dorn

Achim Stoffler

Karl-Heinz Franz

Alexander Kluh

An apparatus is described for the densitometric measurement of printed products such as sheets printed by sheet-fed offset printing machines, having a densitometer measuring head. The head moves along a measurement strip comprising a number of measurement fields and generates signals that are converted into ink density values in a downstream evaluation unit, which is assigned to ink metering zones. The evaluation unit comprising a computer that contains stored information about the arrangement of the measurement fields of the printed colors in each metering zone. The ink density values from one measurement field are compared with the ink density values from neighboring measurement fields of the same color and type in accordance with the known structure of the measurement strip. The invention provides for the simple and fail-safe arrangement of the measurement-field colors in the individual ink metering zones.

Apparatus for the densitometry measurement of printed products

A method and apparatus for controlling the ink feed in a vibrator-type inking unit of a printing machine, especially a sheet-fed offset printing machine, the ink being fed via individual ink metering elements which interact with an ink fountain roller, and the ink metering elements and the vibrator cycle and/or the vibrator strip width being set to correspond to the overall proportion of the printing area of the printing plate and, in order to obtain pre-setting values for the ink feed, the proportion of the printing area in the individual ink metering zones being determined. The method and apparatus are intended to provide an improvement in the transient response of the inking for any desired subject. In the individual ink metering zones, the proportion of the printing area is compared with a predefined limiting value, and in the regions in which the proportion of the printing area is smaller than the predefined limiting value, ink is fed only in at least each second ink metering zone, and in those regions in which the proportion of the printing area is greater than the predefined limiting value, ink is fed in accordance with the proportion of the printing area in each metering zone.

Method and apparatus for ink feed control

A method and a corresponding control are described for the start-up of production printing in a sheet-processing printing machine, in particular, a sheet-fed offset printing machine, in which ink is supplied via a vibrating roller which is movable back and forth between an ink fountain roller and a ink distribution roller wherein clearance is given for the entry into the machine of a first sheet to be printed as a function of the state of movement of the vibrating roller. When production printing is resumed, the state of movement of the vibrating roller for clearance for the sheet entry is selected from a memory as a function of the state of movement of the vibrating roller during entry of a last sheet into the machine before the commencement of the print interruption.

System and method for optimally controlling the restart of a sheet-fed

A control system for controlling the rotational speed of the printing cylinders of a printing machine in order to eliminate register offset or doubling phenomena on the printed matter. The control system uses one or more sensors to determine the operating condition of the printing unit. The relevant operating condition parameters include the frequency of the AC line from which the printing machine operates and the position of the printing cylinders at the time the change in rotational speed is to occur. Based on the operating condition of the printing unit, a controller selects an appropriate timing ramp for increasing or decreasing the rotational speed of the printing cylinders. The various timing ramps are stored on a memory and correspond to the different operating conditions of the printing unit. Once, the appropriate timing ramp has been selected, the controller controls the rotational speed of the drive motor that rotates the printing cylinders in a manner that is proportional to the rate of change and duration characteristics of the selected timing ramp.

Control system for the drive of a printing machine

A method is disclosed for starting-up/restarting continuous printing in a sheet-processing printing machine where the sheets to be printed are fed from a feeder stack connected to the printing machine via a switchable clutch, the feeder assembly is cut-in at a basic speed, and the printing machine is run-up to a continuous printing speed. According to the invention, the time for starting the running up of the printing machine from the basic speed to the continuous production speed is a function of the number of machine revolutions necessary to convey a first sheet from the feeder stack to a predetermined position inside the printing machine such that the first sheet reaches the predetermined position inside the printing machine at the same time or after the production speed is reached. The object of the invention is to reduce the number of rejects that occur during the starting-up/restarting of the printing machine to the largest extent possible.

Method of starting-up/restarting continuous printing in printing

A method and an apparatus for controlling the sheet supply in a sheet-processing printing machine, in particular a sheet-fed offset printing machine. In order that, at the beginning of printing, before which a specific process for predamping and/or preinking the plate and/or blanket cylinders takes place, a first sheet always runs into the printing zone precisely on completion of the process, provision is made for a first sheet to be conveyed by means of the engagement and renewed disengagement of the feeder into a predetermined position from which the number of machine revolutions up to reaching the first printing zone is known. The feeder is disconnected and the separator and pull suckers remain pressurized, thereby continuing to hold a sheet gripped. The process for predamping and/or preinking is then started, whereupon the reengagement of the feeder takes place precisely at that moment after which a first sheet then runs into the first printing zone precisely on completion of the process sequence.

Method and apparatus for controlling the sheet supply in a

A method for controlling the sheet feed in an offset printing machine. A controller, in conjunction with various sensing devices, is utilized to determine the presence of double or misfed sheets as the sheets are removed from a sheet stack in a feeder unit of the printing machine. The controller then, through various actuating devices, shuts down various printing machine functions in order to complete the printing of the sheets ahead of the double or misfed sheets.

Method for controlling sheet feed

A method for regulating ink distribution in a printing machine is disclosed. In accordance with the disclosed method, a basic ink quantity and a compensating ink film thickness are determined for a printing plate to be loaded into the printing machine. All of the inking rollers of the printing machine are fed ink until the ink thickness on each roller is substantially equal to the compensating ink thickness. A steady state ink distribution within the printing machine will be attained relatively quickly, thereby minimizing print waste and time required to attain steady state.

Method for regulating ink distribution in a printing machine

A method for starting/restarting the production run on a sheet-processing printing machine in which the sheets to be printed are fed from a stack to the printing machine by a feeder assembly couplable to the printing machine and including separately actuable members causing removal of sheets from the stack, the method comprising the steps of: rotating the printing machine at a basic rotational speed; cutting in the feeder assembly; running-up the coupled printing machine and feeder assembly to a higher rotational speed, and cutting in the members causing removal of sheets from the stack to cause sheets to be conveyed into the printing machine.

Method for starting the production run on a sheet-processing printing

An apparatus for auxiliary stack formation in a sheet-delivery machine having front and rear stationary stops and a front sheet-retaining device a stack board for receiving sheets, and being moveable rearwardly in a gap above the main stack, the stack board receiving the sheets forming the auxiliary stack, a set of spaced-apart lower rear stops mounted on a horizontally disposed carrier, the carrier being vertically moveable relative to the stationary rear upper stops, between a lower position wherein the lower stops extend beneath the main stack and a upper position wherein the lower stops are above the main stack for preventing rearward movement of the auxiliary stack sheets; wedge members mounted on the carrier, engageable by the advancing stack board for moving the carrier between the lower and upper positions; and a plurality of rear sheet retention devices disposed horizontally in spaced-apart relation and mounted on the carrier for movement between a recessed position behind the rear stops, and a sheet retention position for receiving the rear edges of the auxiliary sheets, the rear sheet retention devices being mounted for combined horizontal and vertical movement between the positions as the carrier moves between the lower and upper positions.

Method and apparatus for the exact separation of main and auxiliary

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.

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Pullach, Germany

Joachim Muller