Proper preparation of the impression cylinder is essential each time a rule is to be used to ensure adherence of the rule's adhesive backing to the cylinder surface. Clean the impression cylinder to remove any oil or grease, and be certain the surface is dry before you apply the rule.
Although careful handling and precise machine settings will minimize damage to the blanket, many printers prefer to use an old blanket to avoid the risk of indentation during the run. When such a blanket is to be reused, always check the position of the previous job to be certain the print matter and the finishing element will not be affected. Also, keep in mind that, on longer runs, the cost of a blanket is nominal compared to the savings afforded by on-press finishing.
Guidelines for positioning of the rules should be clearly placed on the plates. Check before you begin to be certain you will be able to position the rule precisely in accordance with the artwork. Also, be certain you have the appropriate type and size of rule to complete the job correctly.
Now you are ready to begin. Three methods of successful application of Boyd rules have proven equally effective. Each is described and illustrated here. The method you choose should be one that saves you time while ensuring proper positioning and a secure fit. Always remember, regardless of the application method you use, to overlay the rule with the clear film tape provided in the product package. This tape is resistant to press conditions and will not slip during the run. The working edge of the rule will cut through the tape on the first impression.
In this method, you will transfer the plate image directly to the impression cylinder to serve as the guide for positioning the rules. The first step then is to ink up and run through one printing cycle without paper. When the image has been transferred to the cylinder, check to be certain the rule guidelines are clearly visible.
Measure and cut the rule to the designated lengths and remove the paper backing to expose the adhesive surface.
Carefully align the rule with the guidelines on the cylinder and press down firmly on the face of the rule. Now, add a length of clear tape over the rule blade to secure its position. You are now ready to begin the run, however, certain precautions should be included in you preparation.
Be certain that all press parts clear the rule as you set the pressure to begin. You may find it useful to run through some spoil sheets to check the accuracy of rule placement and the pressure against the printed surface.
Too much or too little pressure will affect the performance of the rule and may need to be adjusted before you begin as well as during the run.
This method of application utilizes a printed sheet to serve as the transfer guide. Run through one printing cycle with paper to print your guide.
Place the printed sheet face down on a light table or workbench, and cut the rule to the measured length.
Use a lighter coating of spray adhesive to affix the rule, blade down, to the back of the printed sheet.
Place the chipboard on both sides of the transfer sheet and, with gentle pressure, drive the rule edge into the transfer sheet. Now remove the paper backing to expose the rule's adhesive surface.
Feed the transfer sheet by hand through the press. The rule should transfer readily to the impression cylinder. If unsuccessful, repeat the procedure using a light coating of spray adhesive than before. Use the clear film tape to cover and stabilize the rule once it is positioned, and adjust the pressure before beginning the run so that all parts clear the rule.
This method of application secures the rule to a carrier sheet -- for example, a thin sheet of stable plastic or a printed sheet of paper -- which is then secured to the impression cylinder.
With the carrier sheet lying face up on a table, apply the rule along the guidelines. Use a straight edge for exact lines. Overlay the rule with the clear film tape.
Apply a coat of spray adhesive to the impression cylinder to prepare the approximate area the carrier sheet will cover.
Now, place the carrier sheet in the feeder. Open the sheet detectors wide enough to allow the rule to pass through, and roll the carrier sheet through the detectors by hand.
As the carrier sheet enters the grippers, trip the grippers by hand so that the carrier sheet will stay on the cylinder. Then, use a razor blade or knife and cut the carrier sheet even with the front edge of the cylinder. The carrier sheet should stay affixed to the cylinder. Check for loose edges and corners, and readjust the pressure before starting the run. Upon completion of the job, the plastic sheet may be removed and stored for future use.