ブックタイトルWEB GUIDE CONTROL SYSTEMS

概要

WEB GUIDE CONTROL SYSTEMS

16Principle of EPC with the Servoguide MK-IVThe EPC system arranges the edge of a web consistently.The sensing nozzle detects displacement of the webedge not contacting the web. The primary air pressureis supplied to the sensing nozzle from the blower in theServoguide MK-IV.D controller. The air flux is interruptedby the web edge, and thus secondary air pressure isproduced as a pneumatic output signal proportional todisplacement of the web edge. This pneumatic outputsignal is transmitted to the diaphragm of the Servoguide.The signal is converted into force by the diaphragm tomove the spool. The force generated by the diaphragmis balanced by the spring force when the web edgecovers one half of the slit of the sensing nozzle, and thespool is located at the center.When the edge of a web is displaced, the pneumaticoutput signal actuates the spool of the Servoguide, andthe hydraulic oil from the hydraulic pump is transmittedto the work cylinder. The work cylinder is activated tomove the web in the reverse direction to the meanderto perform EPC and achieve a consistent web edgeposition.The displacement of the edge of a web is detected witha Photohead that does not contact the web. The lightflux from the light source is interrupted by the web edgeand the electromotive force of the detector changes inproportion to the displacement of the web edge. Thiselectromotive force is amplified to a current of +/-200 mADC by the web guide amplifier, and is then transmitted tothe moving coil of the Servoguide.The current signal is converted into a force by the movingcoil, and this force moves the spool. The force of themoving coil is balanced by the spring force when the webedge covers one half of the slit of the Photohead, and thespool is located at the center.When the edge of a web is displaced, the electricalsignal from the moving coil activates the spool of theServoguide, and the hydraulic oil from the hydraulic pumpis transmitted to the work cylinder. The work cylinder isactivated to move the web in the reverse direction to themeander to perform EPC to achieve constant web edgecontrol.Sensing nozzleWork cylinderConstantair pressureDiaphragmPrimaryair pressureSecondaryair pressureReturn oilServo valve body(Sleeve)Hydraulic oilSpoolServoguide MK-IV.D control unitWebPhotoheadWebWork cylinderWebguide amplifierPermanentmagnetMoving coilServo valve body(Sleeve)Return oilHydraulic oilSpoolServoguide MK-IV.M control unitDiagram of working principleDiagram of working principleServoguide MK-IV.M Electro-hydraulic EPCServoguide MK-IV.D Pneumatic-hydraulic EPCServoguide