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AssigneeKoenig & Bauer Aktiengesellschaft
InventorsMichael Müller, Martin Palme
Estimating the term…
In some examples, a sheet-fed printing unit is configured as a screen printing unit and includes at least one screen printing forme cylinder and at least one impression cylinder cooperating therewith. A cylinder barrel of the impression cylinder includes a supporting surface for sheets, and which includes at least one impression portion having a constant barrel radius that extends over an angle of at least 170 degrees about the axis of rotation of the impression cylinder. The screen printing forme cylinder has an effective screen radius that is smaller than a barrel radius of the impression cylinder, and the effective screen radius is larger than half the barrel radius.
A sheet-fed printing unit (700), the sheet-fed printing unit (700) configured as a screen printing unit (700) and comprising at least one screen printing forme cylinder (752) and at least one impression cylinder (708) cooperating therewith, and a cylinder barrel (741) of the at least one impression cylinder (708) including a supporting surface (744) for sheets (02), which comprises at least one impression portion (746) having a constant barrel radius (R1) that extends over an angle of at least 170 degrees about an axis of rotation (716) of the at least one impression cylinder (708), and the at least one screen printing forme cylinder (752) having an effective screen radius (R2), and the effective screen radius (R2) being smaller than the barrel radius (R1), and the effective screen radius (R2) being larger than half the barrel radius (R1).
A method for operating a sheet-fed printing unit (700) configured as a screen printing unit (700), and including a screen printing forme cylinder (752) and an impression cylinder (708) cooperating therewith, and a cylinder barrel (741) of the impression cylinder (708) including a supporting surface (744) for sheets (02), which includes at least one impression portion (746) having a constant barrel radius (R1) that extends over an angle of at least 170 degrees about an axis of rotation (716) of the at least one impression cylinder (708), the at least one screen printing forme cylinder (752) having an effective screen radius (R2), the effective screen radius (R2) being smaller than the barrel radius (R1), and the effective screen radius (R2) being larger than half the barrel radius (R1), the method comprising, during a sequence of several consecutive printing processes and respective interposed adjustment processes, an impression portion (746) of the supporting surface (744) of the cylinder barrel (741) of impression cylinder (708) continuously rotating at a constant circumferential speed about-its the axis of rotation (716), and, during the sequence of several consecutive printing processes, the screen printing forme cylinder (752) forming, together with the impression cylinder (708), a screen printing nip (758) being periodically decelerated and accelerated, and an average angular velocity of the screen printing forme cylinder (752) being identical to an average angular velocity of the impression cylinder (708) cooperating therewith over a respective full process cycle, which lasts from a start of one printing process to a start of a next printing process, and an average circumferential speed of the screen printing forme cylinder (752) being lower than an average circumferential speed of the impression cylinder (708) cooperating therewith over the same respective full process cycle.
Dependencies are inferred from the claim text.