Automated printing press with reinsertion registration control

An automated flexographic printing press having a plurality of printing stations wherein each of the printing stations comprises:

• a frame;
• an impression roller rotatably mounted to the frame;
• a print carriage having a print roller rotatably mounted thereon, the print carriage being movably mounted to the frame to advance in a direction toward the impression roller to a printing position at which the print roller is in printing contact with a substrate between the print roller and the impression roller and to retract in a direction away from the impression roller to at least one non-printing position, including a throw-off position, at which the print roller is out of printing contact with the substrate;
• a swing gear assembly driveably interconnecting the print roller and the impression roller, the assembly including mating gears maintained in a precise mating tolerance when the assembly is in a fully engaged condition, the assembly being swingably mounted so as to be maintainable in the fully engaged condition when the print roller is in the printing position, in the throw-off position, or in a position therebetween, so as to maintain synchronized motion and circumferential registration between the print and impression rollers when in such positions;
• at least one print carriage servo motor connected between the frame and the print carriage and operable to advance and retract the carriage in response to a print roller position control signal;
• a memory having information stored therein of printing position and non-printing position settings of the servo motor representing locations of the respective positions of the rollers on the frame;
• an operator interface having operator command inputs thereon, including a non-printing position command input to select the movement of the carriage to the non-printing position, a print position command input to select the movement of the carriage to the printing position, and incremental adjustment command inputs;
• and,
• a processor programmed to:
• selectively adjust the information stored in the memory in response to the incremental adjustment command inputs, and
• generate the print roller control signal to:
• cause the carriage to move to the print position in response to the print position command input and the stored information, as adjusted, and
• cause the carriage to move to the non-printing position in response to the non-printing position command input and the stored information, as adjusted.

An automated flexographic printing press comprising:

• a plurality of distinct printing stations each for transferring at least one component part of a series of composite images at spaced apart locations along the length of a continuous substrate running therethrough, each of printing stations comprising, located thereat:
• (a) a frame;
• (b) an impression roller mounted for rotation on the frame to back the substrate;
• (c) a print roller rotatably mounted with respect to the frame to print one component part of the image on the substrate being backed by the impression roller;
• (d) a gear train driveably interconnecting the impression roller and the print roller and including a harmonic drive unit connected between the impression roller and the print roller, said harmonic drive unit having a differential input and being operable in response to the differential input to vary the circumferential motion of the print roller relative to the impression roller;
• (e) a stepper motor having an output connected to the differential input of the harmonic drive to drive the differential input in response to a digital control signal to circumferentially incrementally adjust the print roller relative to the impression roller;
• (f) a digital encoder responsive to the angular position of the impression roller at the respective station, the encoder being configured and mounted to produce a signal representing the angular position of the impression roller to an accuracy of within 1/5000 of a revolution thereof;
• (g) an optical sensor operative to produce a signal responsive to the location relative to the impression roller of a previously printed component part of the image on substrate;
• (h) a print roller position sensor operative to produce a signal responsive to the angular position of the print roller relative to the frame;
• and
• (i) a registration controller operable in response to the signals from the encoder and the sensors to calculate a circumferential registration difference between the web and the print roller, to generate, as a result of the calculation, the control signal, and to supply the control signal in the form of a pulse stream to the stepper motor in accordance with circumferential registration difference to maintain circumferential registration among component parts of the images.

An automated flexographic printing press having a plurality of distinct printing stations each for transferring at least one component part of a series of composite images at spaced apart locations along the length of a continuous substrate running therethrough, each of printing stations comprising:

• a frame;
• an impression roller mounted for rotation on the frame to back the substrate;
• a print roller rotatably mounted with respect to the frame to print one component part of the image on the substrate being backed by the impression roller;
• a servo motor connected to move the print roller axially relative to the frame and transverse to the substrate;
• a transverse position sensor operative to generate a timed sensing signal in response to the transverse position of a previously printed component of the image on the substrate;
• and
• a controller operable to actuate the servo motor, in response to the timing of the sensing signal to calculate the transverse position of the substrate and to axially move the print roller transverse of the substrate.

An automated printing press comprising:

• a plurality of printing stations each for transferring one component part of at least one composite image at spaced locations along the length of a continuous substrate when the substrate is extended along a path through the stations, each of the stations having a frame, an impression roller rotatably mounted to the frame and a print roller rotatably mounted on a carriage adjustably supported on the frame to contact the substrate at a print position along the path;
• the path between print positions having more than one possible length;
• a memory having stored therein digital information corresponding to the length of the paths from each print position to at least one other print position;
• each station having a drive train drivably connected to the print roller and the impression roller thereof to drive the rollers at a circumferential speed that corresponds to the lineal speed of the substrate at the station, the drive train including a differential gear unit having a motor connected to a differential input thereof and operative to differentially move the print roller in relation to the substrate in response to a control signal;
• each station having associated therewith a memory having stored therein data relating to the size of the print roller at the respective station;
• and
• each station having located thereat a registration controller operative to supply the control signal to the motor to alter the registration of the print roller relative to the substrate, the controller being operative, in response to a preregistration command, to obtain the path length information relating to the respective station and the data relating to the size of the print roller at the respective station, to calculate therefrom a preregistration angle of orientation of the print roller for the station, and to generate the control signal to cause the differential gear unit to move the print roller of the station to the preregistration angle of orientation.

A method of preregistering the print rollers of a flexographic press having a plurality of printing stations each for transferring one component part of at least one composite image at spaced locations along the length of a continuous substrate extending along a path through the stations, wherein each of the stations includes an impression roller and print roller pair located at a position along the path that is spaced from the positions of other roller pairs by distances that may vary, the method comprising the steps of, at a each of a plurality of the stations:

• receiving and storing in a memory location for the station digital information relating to the distance along the path of the position of the roller pair of the station from the position of the roller pair of another station;
• receiving and storing in a memory at each respective station data relating to the size of the print roller at the station;
• from the information of relative position and the data of a print roller size stored for the station, calculating a preregistration angle corresponding to a remainder that would result by dividing a distance along the path between roller pair positions by a print roller circumference at the respective station;
• sensing a reference moveable with the print roller and determining thereby the angular orientation of the print roller at the station;
• and
• rotating the print roller at the station to the calculated preregistration angle.

A method of controlling the registration of a plurality of component parts of each of a plurality of composite images printed along the length of a continuous substrate, the method comprising the steps of:

• providing a printing press having a plurality of printing stations, each station having a rotatably mounted printing element thereat having a fixed repeat length on the circumference thereof;
• inserting in the printing press and consecutively through the plurality of printing stations a continuous substrate having a plurality of copies of at least one component part of a composite image preprinted along the length thereof, each copy of the preprinted at least one component part being located on a lineal repeat length of the continuous substrate that tends to vary from the fixed repeat length of the printing element;
• running the inserted continuous substrate consecutively through the plurality of stations at a predetermined lineal speed while rotating the printing elements at each of the stations at a respective circumferential speed to print a respective additional component part of the composite image onto each of the preprinted at least one component parts along the substrate;
• measuring a series of the lineal repeat lengths along the continuous substrate running through the stations, and generating a measurement signal representative of a plurality of lineal repeat length measurements;
• calculating separately, for each station, in response to the measurement signal, a correction value representing the predicted difference between the fixed repeat length and the lineal repeat length of the next preprinted at least one component part to be run through the respective station, and generating a control signal carrying a separately calculated correction value for each station;
• and
• separately controlling the actuation of circumferential adjustment means at each station in response to the control signal and in accordance with the respective correction value, so as to automatically change the circumferential speed of the respective printing element relative to the lineal speed of the continuous substrate in order to correct for variations between the lineal repeat lengths of the preprinted at least one component parts and component parts being printed by the printing element at the respective station.

An automated printing press for printing a series of composite images at longitudinally spaced locations along a web by sequentially applying a component of the composite image, each at one of a plurality of printing stations spaced along the web, as the web is advanced through the plurality of printing stations at a controlled web speed, wherein:

• each printing station includes:
• (a) a fixed frame,
• (b) a printing element rotatably mounted with respect to the frame,
• (c) printing element drive linkage connected to the printing element so as to rotate the printing element with respect to the frame at a circumferential speed having a controlled relationship to the controlled web speed,
• (d) an adjustment mechanism coupled to the linkage so as to change the circumferential position of the rotatable printing element relative to the web, the mechanism having an adjustment mechanism actuator responsive to a control signal, and
• (e) at least one sensor having a first output responsive to the circumferential position of the printing element of the respective station and a second output responsive to the position of an image on the continuous web relative to the respective station;
• and
• a computer control configured to derive a measurement error value from the outputs of the sensor, to store a plurality of derived measurement error values, to separately calculate therefrom a correction value for each respective station, and to send to the adjustment mechanism actuator at such station a control signal carrying the calculated correction value.

An automated printing press having a plurality of printing stations for transfer at least one component of a composite image formed of transferable image forming fluid at spaced locations longitudinally along a continuous substrate being advanced through said plurality of printing stations and a web feed operable to advance the continuous substrate consecutively through each of the printing stations at a selected substrate speed, wherein:

• each of said printing stations includes:
• (a) a fixed frame;
• (b) a printing element rotatably mounted with respect to the frame,
• (c) printing element drive linkage connected to the printing element so as to rotate the printing element with respect to the frame at a circumferential speed having a controlled relationship to the controlled web speed,
• (d) a discrete adjustment mechanism coupled to the linkage so as to incrementally change the circumferential position of the rotatable printing element relative to the web, the mechanism having an adjustment mechanism actuator responsive to a digital control signal, and
• (e) at least one sensor having a first output responsive to the circumferential position of the printing element of the respective station and a second output responsive to the position of an image on the continuous web relative to the respective station;
• and
• a computer control configured to derive a measurement error value from the outputs of the sensor, to store a plurality of derived measurement error values, to predict from the stored values error values to be derived at each of the respective stations, to separately calculate therefrom a number of discrete correction pulses required to control the actuation of the adjustment mechanism to compensate for the predicted error values.

An automated printing press comprising:

• a plurality of printing stations for transferring at least one composite image at spaced apart locations along the length of a continuous substrate being run through said plurality of printing stations, each of said plurality of printing stations comprising:
• (a) a frame;
• (b) a rotatable printing element mounted rotatable to apply at least one component image of transferable image forming fluid at spaced apart locations along the length of the continuous substrate;
• (c) a circumferential adjustment mechanism operable to adjust the rotational speed of the rotatable printing element relative to the speed of the continuous substrate running through said printing station;
• (d) a registration controller operable to measure registration errors between images on the web and the rotatable printing elements at each of the stations;
• (e) a computer control responsive to previously measured registration errors, the control including a processor programmed to derive a recurring trend in said previously measured registration errors, to predict a correction component to be made to registration at respective stations, and to control, in response to the predicted correction component and a measured registration error, the actuation of the circumferential adjustment mechanism to automatically change the circumferential orientation of the rotatable printing element relative to the continuous substrate to a desired circumferential orientation in order to correct for circumferential registration errors of the component images being applied by the printing element while the continuous substrate is being run through said printing station.

An automated printing press comprising:

• a plurality of printing stations for transferring at least one composite image at spaced apart locations along the length of a continuous substrate being run through said plurality of printing stations, an unwinding station operable to enable a roll of the continuous substrate to be fed into the plurality of printing stations and a winding station for winding the continuous substrate into a roll after exiting the last of said plurality of printing stations, each of said printing stations comprising:
• (a) a main frame having two sides;
• (b) a rotatable printing element mounted for rotation on the main frame and having image applying surface thereon for applying at least one component image of transferable image forming fluid to the continuous substrate every revolution of said rotatable printing element, a fluid dispenser for dispensing transferable image forming fluid to the image applying surface, and a fluid supply for supplying transferable image forming fluid to the fluid dispenser, the rotatable printing element having a gear mounted thereon;
• (c) an auxiliary frame including a base platform transversely movable from side to side across the main frame, at least the rotatable printing element and the fluid dispenser being carried by said base platform;
• (d) an impression element carried by said frame, the impression element including a backing face for backing the continuous substrate while a component image is being applied thereon;
• (e) a substrate guide carried between the sides of the frame for directing the path of the continuous substrate through the printing station and between the rotatable element and the backing face;
• (f) a gear train for driving the rotation of the rotatable printing element, the gear train including a shiftable gear movable in and out of position to engage and drive the gear mounted to the rotatable printing element;
• (g) a first positioning device operable to move the rotatable printing element to desired positions relative to the backing face, the positions including:
• an image applying position where the rotatable printing element is in position to apply at least one component image of the transferable image forming fluid to the continuous substrate every revolution of the rotatable printing element at which position the shiftable gear in driveable engagement with the gear mounted to the rotatable printing element, and
• a backed off position where the rotatable printing element is not in position to apply a component image to the continuous substrate at which position the shiftable gear is out of driveable engagement with the gear mounted to the rotatable printing element;
• (h) a positioning controller programmed to control actuation of the first positioning device in order to automatically move the rotatable printing element to and from the image applying position and to and from the backed off position;
• (i) a circumferential adjustment mechanism for adjusting the rotational speed of the rotatable printing element independent of the speed of the continuous substrate running through the printing station;
• (j) a sensor for generating at least one measurement signal representative of the position of the printing element relative to an image on the substrate at the station;
• (k) a processor responsive to a plurality of previously generated measurement signals at the respective station for predicting a recurring component of the next measurement signal to be made at the station;
• (l) a circumferential registration controller programmed to control actuation of the circumferential adjustment mechanism in response to the predicted component and the measurement signal to automatically change the circumferential orientation of the rotatable printing element relative to the continuous substrate to a desired circumferential orientation in order to correct for circumferential registration errors of the component images being applied by the printing element while the continuous substrate is being run through the printing station;
• and
• (m) an off-line adjustment device for automatically moving the base platform to a desired transverse position including an operational position in which the rotatable printing element and fluid dispenser are within the frame, and to a stand-aside position in which a sufficient portion of the base platform extends out beyond one side of the frame to enable at least the rotatable printing element and the fluid dispenser to be serviced, the base platform being self-supportive when in the stand-aside position.