Light trap for UV radiation for curing ink on a printing substrate and printing machine including a light trap

Patent metadata

Field	Value
Publication number	US-12377664-B2
Application number	US-202318493851-A
Country	US
Kind code	B2
Filing date	Oct 25, 2023
Priority date	Dec 14, 2022
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

A light trap for ultraviolet radiation for curing ink on a printing substrate contains a shaped body with more than two shape elements succeeding one another. The shaped body has a side facing the printing substrate and embodied to have step elements in a stepped arrangement as shape elements. Every step element contains a pair formed of a step surface and a riser, the step surfaces and the risers having different inclinations relative to the direction of transport. The step surfaces have a step length L and the riser has a step height H, and is characterized in that the following applies: L>2H. This provides an improved UV screen by use of the light trap while simultaneously simplifying the process of cleaning the light trap. This is preferably used in the process of printing and curing UV inks.

First claim

The invention claimed is:

1. A light trap for ultraviolet (UV) radiation for curing ink on a printing substrate, the light trap comprising:
a shaped body having at least three shape elements succeeding one another, said shaped body having a side facing the printing substrate and embodied to have said shape elements being step elements disposed in a stepped configuration, every one of said step elements having a pair formed of a step surface and a riser, said step surface and said riser having different inclinations relative to a direction of transport, said step surface has a step length L and said riser has a step height H,
wherein the following applies: L>2H.

2. The light trap according to claim 1 , wherein said shaped body is disposed to be positioned opposite the printing substrate transported along the light trap in the direction of transport.

3. The light trap according to claim 1 , wherein said step elements succeed one another in or against the direction of transport.

4. The light trap according to claim 3 , wherein said step surface and said riser succeed one another in or against the direction of transport.

5. The light trap according to claim 3 , wherein:
a) said step surface is inclined in the direction of transport and said riser is inclined against the direction of transport; or
b) said step surface is inclined against the direction of transport and said riser is inclined in the direction of transport.

6. The light trap recited in claim 5 , wherein said step surface is inclined a) by less than 90° or b) by more than 90° relative to the direction of transport.

7. The light trap recited in claim 5 , wherein said riser is inclined a) by more than 90° or b) by less than 90° relative to the direction of transport.

8. A printing machine for printing on a printing substrate using an ultraviolet-curable fluid, the printing machine comprising:
a printing head for transferring drops of fluid to the printing substrate;
an ultraviolet (UV) emitter for curing the fluid on the printing substrate using UV light; and
at least one first light trap for the UV light disposed between said printing head and said UV emitter on a first side of the printing substrate and/or at least one second light trap for the UV light disposed on a second side of the printing substrate, wherein said at least one first and second light traps each contain:
a shaped body having at least three shape elements succeeding one another, said shaped body having a side facing the printing substrate and embodied to have said shape elements being step elements disposed in a stepped configuration, every one of said step elements having a pair formed of a step surface and a riser, said step surface and said riser having different inclinations relative to a direction of transport, said step surface has a step length L and said riser has a step height H,
wherein the following applies: L>2H.

9. The printing machine according to claim 8 , wherein said at least one first and second light traps are disposed at a distance of between 0.4 mm and 0.9 mm from the printing substrate.

Assignees

• Heidelberger Druckmasch Ag

Inventors

• Beier Bernard
• Falter Silas
• MüLLER ANDREAS
• Scharf Klaus-Dieter

Classifications

• B41J11/00218 Primary

  Constructional details of the irradiation means, e.g. radiation source attached to reciprocating print head assembly or shutter means provided on the radiation source · CPC title

• B41J11/00214 Primary

  using UV radiation · CPC title