Drying unit for drying printed substrates

Patent metadata

Field	Value
Publication number	US-11220101-B2
Application number	US-201917276552-A
Country	US
Kind code	B2
Filing date	Oct 22, 2019
Priority date	Nov 29, 2018
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

The invention relates to a drying unit (22) for drying printed substrates (21), comprising a chamber (23) with a gaseous medium which is oxygen-reduced by means of an inert gas, wherein the substrates (21) are guided through the chamber (23) or at least can be guided through the chamber, and the chamber (23) has an entrance for the substrates (21) to be guided into the chamber (23) in the transport direction (T) of the substrates (21). The entrance for the substrates (21) to be guided into the chamber (23) is formed by two cylinders (04; 06) which are positioned against each other longitudinally. The cylinders (04; 06) positioned against each other at the entrance of the chamber (23) form a printing unit (03). One of the cylinders (04) is designed as a printing cylinder (04), and the other cylinder (06) is designed as a cylinder (06) which interacts with the printing cylinder (04) and applies a printed image onto the affected substrates (21). The two cylinders (04; 06) which are positioned against each other under pressure at the entrance of the chamber (23) form a seal which runs axially to the cylinders (04; 06) for preventing the oxygen-reduced gaseous medium from leaking out of the chamber (23) and/or for preventing oxygen from the ambient air from entering the chamber (23). The printing unit (03) arranged at the entrance of the chamber (23) is designed as a printing unit (03) for an intaglio printing process.

First claim

The invention claimed is:

1. A drying unit for drying printed substrates, the drying unit comprising:
a chamber configured to hold a gaseous medium that is oxygen-reduced by an inert gas; and
a pair of cylinders longitudinally positioned against each other and forming an entrance of the chamber, the pair of cylinders forming a printing mechanism,
wherein one of the cylinders is a printing cylinder and the other cylinder is a cylinder configured to interact with the printing cylinder, the other cylinder being configured to apply a printed image to the substrates,
wherein the pair of cylinders are configured to guide the substrates into the chamber in a transport direction of the substrates,
wherein the chamber is configured to guide the substrates through the chamber,
wherein the chamber surrounds an arc section of each of the pair of cylinders,
wherein the pair of cylinders are pressed against each other to form a first seal running axially to the pair of cylinders against a leakage of the oxygen-reduced gaseous medium out of the chamber and/or against an infiltration of oxygen from the ambient air into the chamber at the entrance of the chamber, and
wherein the printing mechanism arranged at the entrance of the chamber is configured to print in a gravure printing process.

2. A drying unit according to claim 1 , further comprising a second seal against a leakage of the oxygen-reduced gaseous medium out of the chamber and/or against an infiltration of oxygen from the ambient air into the chamber, wherein the chamber has an exit for the substrates guided through the chamber in the transport direction of the substrates, wherein the second seal is arranged at the exit, and wherein the second seal is a flexible seal or a doctor blade nozzle.

3. A drying unit according to claim 2 , wherein the exit for the substrates guided through the chamber is a slot extending transversely to the transport direction of the substrates across the entire width of the substrates.

4. A drying unit according to claim 3 , wherein the doctor blade nozzle is in the form of a nozzle beam extending longitudinally to the slot-shaped exit of the chamber.

5. A drying unit according to claim 1 , further comprising an electron beam generator configured to direct an electron beam onto the substrates in the chamber to dry the printed substrates.

6. A drying unit according to claim 1 , further comprising the oxygen-reduced gaseous medium, and wherein the oxygen-reduced gaseous medium in the chamber has an oxygen amount of at most 1% and/or the inert gas in the chamber of the drying unit is an elemental gas or a noble gas or a gaseous molecular compound.

7. A drying unit according to claim 1 , wherein the other cylinder interacting with the printing cylinder is formed as a plate cylinder, and wherein the printing cylinder and the plate cylinder are respectively produced from steel.

8. A drying unit according to claim 7 , further comprising a wiping cylinder that is positioned against the plate cylinder, wherein the wiping cylinder is coated with a plastic on its outer surface.

9. A drying unit according to claim 7 , further comprising:
an Orlof-type cylinder positioned against the plate cylinder, and
a plurality of template cylinders,
wherein the plurality of template cylinders of an ink train unit are positioned against the Orlof-type cylinder.

10. A drying unit according to claim 7 , wherein the printing cylinder is formed without a gripper.

11. A drying unit according to claim 1 , wherein at least one of the pair of cylinders is formed as a suction cylinder and comprises a sucker configured to hold the substrate on the outer surface of the suction cylinder.

12. A drying unit according to claim 1 , wherein at least one of the pair of cylinders has at least one gripper configured to hold one of the substrates on the outer surface of the respective cylinder, and wherein the gripper is placed in a groove extending transversely to the transport direction of the substrates.

13. A drying unit according to claim 1 , wherein the printing mechanism arranged at the entrance of the chamber is configured to print in an intaglio printing process.

Assignees

• Koenig & Bauer Ag

Inventors

• Schaede Johannes
• Stierman Robert

Classifications

• B41F9/021

  Sheet printing presses · CPC title

• B41F23/0453 Primary

  by ultraviolet dryers · CPC title

• B41F23/045

  by radiation · CPC title

• B41F23/0486 Primary

  Particular types of dryers · CPC title