Apparatus and method for printing on three-dimensional objects

Patent metadata

Field	Value
Publication number	US-10782633-B2
Application number	US-201816202114-A
Country	US
Kind code	B2
Filing date	Nov 28, 2018
Priority date	May 30, 2016
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

A printing apparatus and method are disclosed for printing on three-dimensional objects. The apparatus employs an offset printing process in which an ink image is deposited onto an intermediate transfer member (ITM) having the form of a flexible endless belt. After drying of the ink image on the ITM, the ITM transports the dried ink image to an impression station having a nip at which the ITM is compressed between an object and an impression surface, so that the dried ink image is transferred from the ITM to the object. The impression surface may form part of a stationary anvil, the ITM sliding relative to the impression surface during passage through the impression station. To optimize throughput, the velocity of the ITM relative to the surface of the object at the impression station may be greater than the velocity of the ITM relative to the imaging station.

First claim

I claim:

1. A printing apparatus for printing on an outer surface of a three-dimensional object having a longitudinal axis, the apparatus comprising:
(i) an intermediate transfer member (ITM) having the form of a flexible endless belt with a release surface;
(ii) an imaging station at which at least one ink composition that comprises a coloring agent, a resin and an optional liquid carrier, is deposited on the release surface to form an ink image;
(iii) a drying station at which the ink image is substantially dried, by evaporation of any liquid carrier in the ink or by exposure to radiation to cure the ink, so as to form a dried ink image on the release surface;
(iv) an impression station having a nip at which the ITM is compressed between an object and an impression surface, so that the dried ink image is transferred from the release surface of the ITM to an outer surface of the object; and
(v) an object transport system for transporting objects to the impression station and rotating each object about its own longitudinal axis during passage through the impression station such that, at the nip, the outer surface of each object makes rolling contact with the release surface of the ITM,
wherein the impression surface forms part of a stationary anvil, the ITM sliding relative to the impression surface during passage through the impression station.

2. The printing apparatus of claim 1 , wherein a velocity of the ITM relative to the surface of the object at the impression station is greater than a velocity of the ITM relative to the imaging station.

3. The printing apparatus of claim 2 , wherein the ITM travels at the impression station at a higher velocity than at the imaging station and wherein buffers are provided to accommodate velocity differences.

4. The printing apparatus of claim 2 , wherein, at the impression station, a direction of movement of objects by the object transport system is opposite to a movement of the ITM at the impression station, a velocity of movement of the ITM being uniform over its entire length.

5. The printing apparatus of claim 1 , wherein the impression surface is concave in a direction facing the object.

6. The printing apparatus of claim 1 , wherein the impression surface is convex in a direction facing the object.

7. The printing apparatus of claim 1 , wherein the impression surface has a length, measured in a direction of movement of the ITM, that is shorter than a circumference of the object.

8. The printing apparatus of claim 1 , further comprising a conditioning station upstream of the imaging station at which the release surface is conditioned to facilitate at least one of retention of the ink image on the release surface during transit from the imaging station to the impression station and transfer of the dried ink image from the ITM to the surface of the object.

9. The printing apparatus of claim 8 , wherein the release surface is chemically conditioned, the conditioning including the application of a thin layer of a treatment liquid upon the release surface, the thin layer being substantially dry upon entry of the ITM into the imaging station.

10. The printing apparatus of claim 1 , further comprising a pre-processing station for processing at least a portion of the surface of the object prior to passage of the object through the impression station.

11. The printing apparatus of claim 1 , further comprising a post-printing station for processing at least a portion of the surface of the object after transferring the dried ink image to the surface of the object.

12. The printing apparatus of claim 1 , wherein the ITM is fiber-reinforced so as to be substantially non-extendible.

13. The printing apparatus of claim 1 , wherein the ITM is elastically deformable during passage through the impression station to permit printing on a non-cylindrical object surface.

14. The printing apparatus of claim 13 , wherein the ink image formed at the imaging station on the release surface is a distorted mirror image of the image to be transferred to the object, the distortion compensating for stretching of the ITM.

15. The printing apparatus of claim 1 , further comprising a station for reducing a temperature of the ITM after transferring the dried ink image to the object.

16. The printing apparatus of claim 1 , further comprising a cleaning system for cleaning the release surface of the ITM after transfer of the dried ink image.

17. The printing apparatus of claim 1 wherein the release surface of the ITM is hydrophobic.

18. The printing apparatus of claim 1 , wherein the ink composition is aqueous.

19. The printing apparatus of claim 1 , wherein, at the impression station, no part of the impression surface opposes any sharp edge of the object.

20. The printing apparatus of claim 1 , further comprising a compressible member to enhance the contact between the dried ink image carried by the release surface of the ITM and the surface of the object.

21. The printing apparatus of claim 20 , wherein the compressible member includes a compressible blanket pad positioned on the impression surface and shaped in accordance with a shape of the object.

22. The printing apparatus of claim 1 , further comprising a plurality of first print heads which are not comprised in the imaging station, said imaging station comprising a plurality of second print heads.

23. A method of retrofitting a three-dimensional object printing system, the method comprising:
providing a three-dimensional object printing system, the object printing system including a plurality of first print heads;
installing a sub-assembly, the sub-assembly including an intermediate transfer member (ITM) having the form of a flexible endless belt with a release surface,
an imaging station at which at least one ink composition that comprises a coloring agent, a resin and an optional liquid carrier, is deposited on the release surface to form an ink image, the imaging station including a plurality of second print heads, and
a drying station at which the ink image is substantially dried, by evaporation of any liquid carrier in the ink or by exposure to radiation to cure the ink, so as to form a dried ink image on the release surface; and

adapting said system to said sub-assembly, including retaining the plurality of first print heads separate from the imaging station or removing the plurality of first print heads,
wherein the adapted system includes an impression station having a nip at which the ITM is compressed between an object having a longitudinal axis and an impression surface, so that the dried ink image is transferred from the release surface of the ITM to an outer surface of the object, and wherein each object rotates about its own longitudinal axis during passage through the impression station such that, at the nip, the outer surface of each object makes rolling contact with the release surface of the ITM, and wherein the impression surface forms part of a stationary anvil, the ITM sliding relative to the impression surface during passage through the impression station.

24. A method of printing on an outer surface of a three-dimensional object having a longitudinal axis, the method comprising:
depositing on a release surface of an intermediate transfer member (ITM) having the form of a flexible endless belt at least one ink composition that comprises a coloring agent, a resin and an optional liquid carrier to form an ink image;
substantially drying the ink i

Assignees

• Landa Labs 2012 Ltd

Inventors

• Landa Benzion

Classifications

• G03G15/2014

  using contact heat · CPC title

• G03G15/1615 Primary

  relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning · CPC title

• B41J2002/012

  with intermediate transfer member · CPC title

• B41J11/00214 Primary

  using UV radiation · CPC title

• B41J11/002

  Curing or drying the ink on the copy materials, e.g. by heating or irradiating · CPC title