Coating apparatus for sheet-fed, offset rotary printing presses

Apparatus for applying liquid material from a supply to a pickup roller comprising in combination:

• a doctor blade head having an elongated reservoir for receiving liquid material from the supply, said doctor blade head being adapted to extend in parallel with the pickup roller in an operative position with a portion of the peripheral surface of the pickup roller extending into said reservoir for wetting contact with liquid material contained therein, and two doctor blades attached to said doctor blade head for engagement against said peripheral surface in the operative position;
• first means coupled to said supply and to said reservoir for pumping liquid material from said supply into said reservoir;
• and,
• second means coupled to said reservoir and to said supply for inducing suction flow of liquid material from said reservoir into said supply.

In a sheet-fed, offset rotary printing press of the type including at least one printing station having a blanket cylinder and an impression cylinder disposed for printing ink onto sheets passing therebetween, and a delivery conveyor system for pulling freshly printed sheets from the impression cylinder and transporting the printed sheets toward a sheet delivery stacker, the delivery conveyor system including a delivery drive shaft disposed adjacent to and extending parallel with the impression cylinder and driven in timed synchronous relation with the impression cylinder, the improvement comprising:

• a delivery cylinder mounted onto said delivery drive shaft and having an outer peripheral support surface adapted to engage and support a sheet being transported by said delivery conveyor system;
• a coating apparatus including a supply of liquid material, a rotatable pickup roller having an outer peripheral surface of substantially cylindrical shape, and means for applying a coating of liquid material from said supply onto said outer peripheral surface of said pickup roller;
• means for mounting said coating apparatus to the press adjacent said delivery cylinder with a portion of said peripheral surface of said pickup roller engaged with the support surface of said delivery cylinder, whereby liquid coating material from said supply applied onto the peripheral surface of said pickup roller is transferred to said support surface of said delivery cylinder and to said freshly printed sheet;
• said coating apparatus including an elongated reservoir for receiving liquid material from said supply, said reservoir extending parallel with said pickup roller with a portion of the peripheral surface of the pickup roller extending into said reservoir for wetting contact with liquid material contained therein, and two doctor blades attached to said reservoir and engaging said peripheral surface, said doctor blades acting to limit the amount of liquid material applied onto said peripheral surface from said reservoir;
• a supply conduit connecting said supply in flow communication with said reservoir;
• a return conduit connecting said reservoir in flow communication with said supply;
• and,
• a first pump coupled in series flow relation with said return conduit for inducing suction flow return of liquid material from said reservoir to the remote supply.

In a sheet-fed, offset rotary printing press of the type including at least one printing station having a blanket cylinder and an impression cylinder disposed for printing wet ink onto sheets passing therebetween, and a delivery conveyor system for pulling freshly printed sheets from the impression cylinder and transporting the printed sheets toward a sheet delivery stacker, the delivery conveyor system comprising a pair of endless gripper chains disposed on opposite sides of the press and supporting therebetween gripper bars and grippers spaced along the chains, the gripper chains being driven in timed synchronous relation with the impression cylinder by laterally spaced sprocket wheels mounted on opposite ends of a delivery drive shaft disposed adjacent to and extending parallel with the impression cylinder, the improvement comprising:

• a delivery cylinder mounted to said delivery drive shaft between said sprocket wheels and having an outer peripheral support surface covered by a removable coating blanket adapted to engage and support the wet ink side of a sheet being transported by said gripper bars;
• a coating apparatus including a supply of liquid material, a rotatable pickup roller having an outer peripheral surface of substantially cylindrical shape, and means for applying liquid material from said supply onto said peripheral surface of said pickup roller;
• means for mounting said coating apparatus to the press adjacent the delivery cylinder, with a portion of the outer peripheral surface of said pickup roller engaged with said delivery cylinder, whereby liquid material doctored onto the peripheral surface of said pickup roller is transferred to said delivery cylinder and to said freshly printed sheet;
• said coating apparatus including an elongated reservoir containing liquid material, said reservoir being disposed to extend parallel with said pickup roller with a portion of said peripheral surface extending into said reservoir in contact with liquid material contained therein, and two doctor blades attached to said reservoir and engaging said peripheral surface, said doctor blades acting to limit the amount of liquid coating material applied onto said peripheral surface from said reservoir;
• a supply conduit connecting said supply in flow communication with said reservoir;
• a return conduit connecting said reservoir in flow communication with said supply;
• and,
• a first pump coupled in series flow relation with said return conduit for inducing suction flow return of liquid material from said reservoir to said supply.

A sheet-fed, offset rotary printing press including:

• at least one printing station having a blanket cylinder and an impression cylinder disposed for printing wet ink onto sheets passing therebetween;
• a delivery conveyor system for pulling freshly printed sheets from the impression cylinder and transporting the printed sheets toward a sheet delivery stacker, the delivery system including a delivery drive shaft;
• a delivery cylinder mounted to said delivery drive shaft and having an outer peripheral support surface adapted to engage and support a sheet being transported by said delivery conveyor system;
• a coating apparatus including a supply of liquid material, a rotatable pickup roller having an outer peripheral surface of substantially cylindrical shape, and means for applying liquid material from said supply onto the peripheral surface of said pickup roller;
• means for mounting said coating apparatus to the press adjacent said delivery cylinder, with a portion of said peripheral surface of said pickup roller engaged with said delivery cylinder, whereby liquid material applied to the peripheral surface of said pickup roller is transferred to said delivery cylinder and then to said freshly printed sheet;
• said coating apparatus including an elongated reservoir containing liquid material, said reservoir being disposed to extend parallel with said pickup roller with a portion of said peripheral surface extending into the reservoir in contact with liquid material contained therein, and two doctor blades attached to said reservoir and engaging said peripheral surface, said doctor blades acting to limit the amount of liquid coating material applied onto said peripheral surface from said reservoir;
• a supply conduit connecting said supply in flow communication with said reservoir;
• a return conduit connecting said reservoir in flow communication with said supply;
• and,
• a first pump coupled in series flow relation with said return conduit for inducing suction flow return of liquid material from said reservoir to said supply.