Method of printing sheets

Claim 1

A method of sheet-fed printing comprising, providing a sheet; providing a printing press having at least two adjacent rotatable printing cylinders; positioning the leading edge of a sheet in a gripper element; moving the gripper element toward and between the printing cylinders in a straight line substantially normal to a line intersecting the tangent point of the cylinders and the longitudinal axes thereof; printing on both sides of the sheet carried by the gripper element at substantially the same instant; and moving the gripper element away from the printing cylinders in a substantially straight line to disengage the sheet from surfaces of each of the printing cylinders whereby the sheet when passing between the cylinders is maintained in substantial line contact with the cylinders.

Claim 2

A method of sheet-fed printing comprising, providing a sheet; providing a printing press having at least two adjacent rotatable printing cylinders; positioning the leading edge of a sheet in a gripper element; moving the gripper element toward and between the printing cylinders in a straight line substantially normal to a line intersecting the tangent point of the cylinders and the longitudinal axes thereof; printing on both sides of the sheet carried by the gripper element at substantially the same instant; and moving the gripper element away from the printing cylinders in a substantially straight line to disengage the sheet from surfaces of each of the printing cylinders whereby the sheet when passing between the cylinders is maintained in substantial line contact with the cylinders.

Claim 4

A method of printing on a sheet as said sheet is moved between adjacent rotating printing and impression cylinders comprisng steps of, providing a sheet having a length which is less than the circumference of the printing cylinder; attaching the sheet in a gripper element adjacent the leading edge of the sheet; moving a conveyor at a uniform speed in non-driving relation to printing and impression cylinders to move the gripper element; guiding the gripper element toward, between and away from the printing cylinder and the impression cylinder such that the sheet substantially bisects the cusp area formed by adjacent converging surfaces of the printing and impression cylinders; and printing on the sheet as it is moved between the printing cylinder and the impression cylinder.

Claim 5

A method of printing on a sheet as said sheet is moved between adjacent rotating printing and impression cylinders comprisng steps of, providing a sheet having a length which is less than the circumference of the printing cylinder; attaching the sheet in a gripper element adjacent the leading edge of the sheet; moving a conveyor at a uniform speed in non-driving relation to printing and impression cylinders to move the gripper element; guiding the gripper element toward, between and away from the printing cylinder and the impression cylinder such that the sheet substantially bisects the cusp area formed by adjacent converging surfaces of the printing and impression cylinders; and printing on the sheet as it is moved between the printing cylinder and the impression cylinder.

Claim 6

A method of printing comprising the steps of: positioning the leading edge of a sheet in a gripper element; moving the gripper element along a substantially straight path toward, through and away from a plurality of printing stations whereby the sheet when passing between adjacent cylinders in thh printing station is maintained substantially in line contact with the cylinders; urging the gripper element laterally across the path into engagement with an indexing surface adjacent each printing station; and disengaging the leading edge of the sheet from the gripper element after the sheet has been moved through each of the printing stations.

Claim 7

A method of printing comprising the steps of: positioning the leading edge of a sheet in a gripper element; moving the gripper element along a substantially straight path toward, through and away from a plurality of printing stations whereby the sheet when passing between adjacent cylinders in thh printing station is maintained substantially in line contact with the cylinders; urging the gripper element laterally across the path into engagement with an indexing surface adjacent each printing station; and disengaging the leading edge of the sheet from the gripper element after the sheet has been moved through each of the printing stations.

Claim 8

A method of transferring sheets to, through and out of a printing nip between a pair of adjacent cylinders, at least one of which has a longitudinally extending gap formed therein comprising the steps of: rotating an endless flexible tape having spaced gripper elements secured thereto such that each gripper element moves along substantially straight tracks passing adjacent opposite ends of the printing nip; restraining each gripper element Against longitudinal movement transversally of one of the tracks; rotating the cylinders such that each gripper element passing therebetween will be positioned in a longitudinally extending gap; positioning the leading edge of a sheet in a gripper element such that movement of the gripper element will transfer the sheet to, through and out of the printing nip; and disengaging the leading edge of a sheet from the gripper element after the sheet has moved out of the printing nip.

Claim 9

A method of transferring sheets to, through and out of a printing nip between a pair of adjacent cylinders, at least one of which has a longitudinally extending gap formed therein comprising the steps of: rotating an endless flexible tape having spaced gripper elements secured thereto such that each gripper element moves along substantially straight tracks passing adjacent opposite ends of the printing nip; restraining each gripper element Against longitudinal movement transversally of one of the tracks; rotating the cylinders such that each gripper element passing therebetween will be positioned in a longitudinally extending gap; positioning the leading edge of a sheet in a gripper element such that movement of the gripper element will transfer the sheet to, through and out of the printing nip; and disengaging the leading edge of a sheet from the gripper element after the sheet has moved out of the printing nip.