Sheet-transport drum and printing machine with a sheet-transport drum

Patent metadata

Field	Value
Publication number	US-9718286-B2
Application number	US-201615188005-A
Country	US
Kind code	B2
Filing date	Jun 21, 2016
Priority date	Jun 22, 2015
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A sheet-transport drum includes at least two sheet-supporting surfaces with suction openings. Each respective sheet-supporting surface is formed of first and second comb segments with segment teeth. Suction grooves are provided in the segment teeth and a trailing-edge suction groove is provided in the sheet-supporting surface of each respective second comb segment. A rotary valve is provided for a timed supply of suction air. A plurality of vacuum sources is provided and a trailing-edge suction groove is assigned to each respective vacuum source by the rotary valve. This ensures that the vacuum provided by a respective trailing-edge suction groove at the trailing edge of a respective sheet is reliably maintained even if a previous or following sheet is missing. A sheet-fed printing machine with the sheet-transport drum is also provided.

First claim

The invention claimed is:

1. A sheet-transport drum in a sheet-processing machine, the sheet-transport drum comprising:
at least two sheet-supporting surfaces having suction openings formed therein, each of said sheet-supporting surfaces being formed of a respective first comb segment and a respective second comb segment, said comb segments having segment teeth with suction grooves formed therein;
each of said second comb segments of said at least two sheet-supporting surfaces having a respective trailing-edge suction groove formed therein;
a plurality of vacuum sources; and
a rotary valve for providing a timed supply of suction air, said rotary valve associating each of said trailing edge-suction grooves with a respective one of said vacuum sources.

2. The sheet-transport drum according to claim 1 , which further comprises a transfer region of the sheet-transport drum in which a separate vacuum source of said plurality of vacuum sources is associated with said suction grooves by said rotary valve.

3. The sheet-transport drum according to claim 2 , wherein a further vacuum source of said plurality of vacuum sources is associated with said suction grooves by said rotary valve.

4. The sheet-transport drum according to claim 1 , wherein said vacuum sources are operable at different pressure levels.

5. The sheet-transport drum according to claim 1 , wherein said comb segments have air control holes formed therein interacting with said rotary valve, and said rotary valve has supply lines located therein for said air control holes ( 24 , 25 , 26 ).

6. The sheet-transport drum according to claim 5 , wherein said supply lines are formed in said rotary valve and include a supply line for supplying said trailing-edge suction groove, a supply line for supplying said suction grooves of said respective first comb segments, and a supply line for supplying said suction grooves of said respective second comb segment.

7. The sheet-transport drum according to claim 6 , wherein at least said supply line for said trailing-edge suction groove is subdivided into separate sections and each one of said sections provides suction air to only one respective trailing-edge suction groove.

8. The sheet-transport drum according to claim 7 , wherein each of said sections is connected to a respective one of said vacuum sources.

9. The sheet-transport drum according to claim 1 , wherein the sheet-transport drum is a jetting cylinder.

10. A printing machine, comprising a sheet-transport drum with vacuum sources according to claim 1 .

11. A digital printing machine, comprising a sheet-transport drum with vacuum sources according to claim 1 .

Assignees

• Heidelberger Druckmasch Ag

Inventors

• Dolz Wolfgang
• Schroeder Raimund
• Juenger Arno
• Conzelmann Daniel

Classifications

• B41J11/0085 Primary

  Using suction for maintaining printing material flat (on rotatable drums B41J13/226) · CPC title

• B41J2/01

  Ink jet · CPC title

• B41F21/102 Primary

  with pneumatic means (B41F21/108 takes precedence) · CPC title

• B41F21/00

  Devices for conveying sheets through printing apparatus or machines (through platen presses B41F1/28) · CPC title

• B41F21/04

  Grippers ({B41F21/08, B41F21/10} B41F21/12, B41F21/14 take precedence) · CPC title