AU737480B2

AU737480B2 - Process for coating and sublistatically printing ceramic articles

Info

Publication number: AU737480B2
Application number: AU83052/98A
Authority: AU
Inventors: Bryan Hopkins
Original assignee: XPRES Corp
Current assignee: XPRES Corp
Priority date: 1998-02-06
Filing date: 1998-09-02
Publication date: 2001-08-23
Anticipated expiration: 2018-09-02
Also published as: GB2333998A; ZA986935B; AU8305298A; GB9815687D0; GB2333998B

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): XPRES CORPORATION Invention Title: PROCESS FOR COATING AND SUBLISTATICALLY PRINTING CERAMIC

ARTICLES

~r The following statement is a full description of this invention, including the best method of performing it known to me/us: PROCESS FOR COATING AND SUBLISTATICALLY PRINTING CERAMIC ARTICLES BACKGROUND OF THE INVENTION 1. Field of the Invention. The present invention relates generally to a process for preparing ceramic articles for surface printing and thereafter sublistatically printing on these article surfaces by positioning a sublistatic transfer sheet against the article surfaces.

2. Description of the Prior Art. There are a number of techniques presently being utilized to prepare ceramic and glass articles for surface printing. Additionally, there are numerous devices available for effecting sublistatic printing on ceramic and glass article surfaces.

In all such devices, the processes are separate and distinct. Pretreated ceramic or glass articles are introduced to a sublistatic printing process for a subsequent operation. In all of these cases, the process is slow and rather inefficient, particularly then there are actually two processes in use instead of a single assembly line for effecting both preparation of article surfaces and actual printing of the surfaces.

-2- Thus, there is a need to automate ceramic or glass article preparation and printing techniques to the extent possible in order to increase the output of the two operations to provide an adequate volume of such articles and to more effectively provide printed articles of various types.

SUMMARY AND OBJECTIVES OF THE INVENTION The present invention is a process for coating and oooo subsequently sublistatically printing ceramic and glass articles on the article surface and includes the steps of: "washing the articles in an appropriate washer, rinsing the articles, positioning the articles on support devices so they can be moved generally through an open area for drying, applying to the articles. a dye-receptive solution to form a coating thereon, moving the articles through an oven to cure the dye-receptive material, inspecting the dry coated articles for quality and consistency of coating thickness, and printing or otherwise decorating the surfaces of the ceramic articles by the use of a sublistatic transfer sheet held against the article surface by a mechanical device such as, for example, an elastic band.

-3- With this brief summary and other comments concerning the invention in mind, it is therefore a primary objective of the present invention to provide a process for coating and sublistatically printing ceramic and glass articles which-will include all of the advantages of the prior art processes of this nature, and none of the disadvantages.

Another objective of the present invention is to provide a single process that will combine the preparation of ceramic and glass articles with the surface printing of such articles.

Yet another objective of the present process is to provide a process for coating and sublistatically printing ceramic and glass articles that will result in a high quality dye-receptive coating, a consistency of coating thickness, and a sharper.printed image than has heretofore oe 0 been obtained.

Thus, there has been outlined the more important features of the invention in order that the description that follows may be better understood and in order that this contribution may be better appreciated. There are additional features of the invention that will be described hereinafter that will also form the subject matter of the claims appended hereto. In this respect, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in several ways. The phraseology and terminology employed herein are for the purpose of description and are not to be regarded as limiting. Those skilled in the art will appreciate that the concept upon which this disclosure is based may readily be utilized as a basis for the design of other structures, methods, and systems for carrying out the several purposes of the invention. In that respect, the claims are to be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present invention.

Consequently, the objectives set forth above, together with other objectives of the invention, along with the various features of novelty which characterize the invention, will become more apparent after consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings wherein like characters of reference designate like parts throughout several views.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan and schematic of a floor plan of the facility utilizing the process of the present invention.

Figure 2 is a perspective view of an apparatus for effecting sublistatic printing.

oooo DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing marked Fig. 1, a plurality of ceramic or glass articles are placed into trays or "positioned onto a conveyor 10 at a loading area (12) for movement through the continuous operation embodying the present inventive concept. For purposes of this description, the ceramic or glass articles will be mugs, such as those used for coffee or tea, which have become quite popular when printed for resorts as souvenirs or as corporate endorsements. While the process is equally applicable to other ceramic and glass articles such as decorative tiles and the like, it will be more convenient to refer generally to mugs a representative of those articles for the balance of this description.

It may be possible for uncoated mugs to arrive uncontaminated to the extent that wash/rinse is unnecessary.

In most situations however, it is desirable to include the wash and rinse steps as will be done in the present inventive process to maximize the amount of product of acceptable quality.

Mugs are loaded at loading area 12, onto trays, racks or directly onto a meshed belt and moved into a C C prewash/washer compartment 14 where a thorough cleaning of o the mug surface is undertaken to remove any foreign substances associated therewith. From the washer, the mugs are moved to the rinse compartment 16, where they are c* C* exposed to fresh water. The clear rinse water may contain chemical drying agents which function to reduce the surface eC tension of the residual water on the mugs, thus facilitating more rapid drying in the open atmosphere. The drying agent per se. is not part of the present invention, except as used in steps of the process and is available commercially from, for example, Ecolabs, Inc.

I Just prior to being exposed to the drying action, (in this example atmospheric drying), the mugs are loaded onto support devices at loading station 18 which is designed to maximize the surface exposure of the mug, so that the exterior and other surfaces of the mug can be exposed to the drying action and to the other operations subsequently tobe described.

The supported articles are then moved through an :extended conveyor system shown generally as 20 where :0 atmospheric drying takes place. The conveyor arrangement 0 extends through a coating booth 22 where mugs are sprayed 0 .0 with a dye-receptive solution to form a coating on all exposed surfaces. Since the conveyor is continuously in motion, the movement and activation of the spray guns that automatically apply coating material to the mugs as they 0.0.

o 0.00*pass through the coating booth is coordinated with the conveyor movement by the tracking unit 24 appropriately programmed.

From the spray booth, the mugs move on to enter a separately enclosed oven shown generally as 26, where they traverse the necessary conveyor lengths to achieve adequate drying and curing of the applied coating material.

Conventional ovens (convection or radiant) may be used for the curing operation and are quite effective for this purpose, however, it has been found that in most cases the ovens utilizing infrared emitters provide the most expedient and consistent curing of the ceramic articles. In this description, infrared curing will be employed.

After the articles have been dried and cured in the oven, they are conveyed to an inspection station 28 where *chey are removed from extended conveyor 20. Here they are e inspected (100% or statically sampled) for consistency of coating thickness.

Mugs that are of acceptable quality are then conveyed to a wrapping station 30, where a sublistatic transfer sheet is applied and held against the article surface by a mechanical device. Sublistatic printing is most effectively done by utilizing equipment such as disclosed in U.S. Patent No. 4,989,508 entitled Device for Facilitating Sublistatic Printing. This device facilitates sublistatic printing by positioning transfer sheets intimately against the surfaces of the articles to be imprinted and which includes a mechanical device, usually in the form of an elastic band, that envelopes or encircles the arcuate surfaces of an article to be imprinted to hold the sublistatic transfer sheet in place against the article surface and to exert a uniform perpendicular or radial pressure thereagainst. The elastic band is of sufficient stretched length to encircle the article and of sufficient diminished width when stretched to substantially cover the entire area to be printed. A gripping or holding element may be affixed to each end of the band and may include fixtures which connect to one another to secure the band after it encircles the article to be imprinted. Full details of the operation of the device are shown in-U.S. Patent No. 4,989,508 and are incorporated herein by reference.

The articles with a sublistatic transfer sheet positioned against the surface, and with the elastic band encircling the articles, are conveyed through an oven 32.

Oven 32 may be conventional or infrared. Sufficient heat is applied to initiate sublistatic printing onto costly material.

From oven 32, mugs are conveyed to an inspection area 34 where the elastic band is removed, the sublistatic transfer sheet is removed, and the final product is inspected for printing sharpness, registration and color.

It has been found most effective to keep the temperature of the clear water and rinse solution within a range of 180 degrees Fahrenheit to 212 degrees Fahrenheit for maximum results. It has also been found that drying and curing of bi-component, dye-receptive coating materials in a production environment requires a minimum surface temperature of 365 degrees to achieve a satisfactory cure.

Typical surface temperatures would be within the range of 365 degrees Fahrenheit to 410 degrees Fahrenheit. It has oooo also been found most effective to utilize temperatures of from 325 to 400 degrees Fahrenheit during the sublistatic printing of coated ceramic articles. Variations of these %oo parameters occur due to the size of the ceramic being ooee° g0.0 printed, the number of pieces being heated, and characteristics that are unique to different manufacturer's e S. dyes and dye-receptive materials.

From the preceding description, it can be seen that a process for coating and sublistatically printing ceramic article surfaces has been provided that will meet all of the advantages of prior art processes and offer additional advantages not offered by such processes. Moreover, the use of a continuous conveyor system, and optionally, an infrared

-I-

oven, expedites the process timing thereby resulting in greater volume and more efficient and less expensive procedures.

With respect to the foregoing description, the optimum dimensional relationship to the parts of the invention including variations in size, materials, shape form, function, and manner of operation, use and assembly are deemed readily apparent to those skilled in the art and all equivalent relationships illustrated in the drawings and eoc described in the specification are intended tobe encompassed herein.

0. The foregoing is considered illustrative only of the o principles of the invention. Since numerous modifications and changes will readily occur to those skilled in the art, it is intended not to limit the invention to the precise Sdescription and operation of the embodiment shown. All description and operation of the embodiment shown. All suitable modifications and equivalents that fall within the scope of the appended claims are deemed within the present inventive concept.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

Claims

2. The process as claimed in claim 1 wherein the articles are introduced into a spray booth prior to the spraying operation.
3. The process as claimed in claim 1 wherein the support devices include one or more conveyors.
4. The process as claimed in claim 2 wherein the support devices include one or more conveyors. The process as claimed in claim 1 wherein the article preparation includes washing the articles in a solution containing clear water and a drying agent.
6. The process as claimed in claim 5 wherein the temperature of the rinse solution is within a range of 180 degrees Fahrenheit to 212 degrees Fahrenheit.
7. The process as claimed in claim 1 wherein the surface temperature of the articles is within a range of 365 degrees Fahrenheit to 410 degrees Fahrenheit. oooo
8. The process as claimed in claim 2 wherein the surface temperature of the articles is within a range of 365 degrees Fahrenheit to 410 degrees Fahrenheit.
9. The process as claimed in claim 3 wherein the oo e :e surface temperature of the articles is within a range of 365 degrees Fahrenheit to 410 degrees Fahrenheit. e•
10. The process as claimed in claim 4 wherein the surface temperature of the articles is within a range of 365 degrees Fahrenheit to 410 degrees Fahrenheit.
11. The process as claimed in claim 5 wherein the surface temperature of the articles is within a range of 365 degrees Fahrenheit to 410 degrees Fahrenheit. -14-
12. The process as claimed in claim 1 wherein the article is a mug.
13. The process as claimed in claim 5 wherein the article is a mug.
14. The process as claimed in claim 6 wherein the article is a mug. The process as claimed in claim 1 wherein the oven is an infrared oven.
16. The process as claimed in claim 5 wherein the oven is an infrared oven.
17. The process as claimed in claim 6 wherein the oven .is an infrared oven.
18. The process as claimed in claim 7 wherein the oven is an infrared oven.
19. The process as claimed in claim 14 wherein the oven is an infrared oven. The process as claimed in claim 1 wherein sublistatic printing is carried out within a range of 325 degrees Fahrenheit to 400 degrees Fahrenheit.
21. The process as claimed in claim 5 wherein sublistatic printing is carried out within a range of 325 degrees Fahrenheit to 400 degrees Fahrenheit.
22. The process as claimed in claim 11 wherein sublistatic printing is carried out within a range of 325 degrees Fahrenheit to 400 degrees Fahrenheit.
23. The process as claimed in claim 1 wherein sublistatic printing is carried out within a range of 325 degrees Fahrenheit to 400 degrees Fahrenheit. Dated this 2nd day of September, 1998 XPRES CORPORATION By its Patent Attorneys GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia a f o