Claims
- 1. The combination of a screen printing and a curing apparatus for curing screen printed ink on articles, said combination comprising:
- a screen printer having an indexable turntable with platens to carry articles from station to station about a central pivot axis, said articles being stationary at each station for a predetermined period of time;
- a plurality of printing heads for screen printing ink on the articles at a printing station;
- a curing apparatus at a curing station having electrically powered curing elements for curing ink printed on the articles indexed into the curing station on the turntable;
- circuit means for supplying electrical power to the electrically powered curing elements;
- manually operable power control means in the circuit means for varying the power to a lower level at a percentage of full power to operate the electrically powered curing elements at a desired operating and curing temperature for curing the ink while the articles are stationary for a predetermined time period;
- said power control means having a start circuit for applying a substantially higher level of power to the curing elements to raise said elements toward a temperature substantially higher than the operating temperature to reduce the time needed to warm up the curing elements for the curing; and
- sensing means for sensing the temperature of the curing elements and for disabling the start circuit and enabling the manually operable control means to return the circuit means to the control of the power control means to operate the electrically powered curing elements at the preselected lower level of power for providing the desired operating and curing temperature.
- 2. The combination in accordance with claim 1 including a timer means in the circuit means to time out and interrupt the power to the heating elements, and cycle control means responsive to the indexing of a platen and workpiece to generate a control signal to restart the timer means.
- 3. Heating apparatus for curing stationary articles on an automatically indexing screen printing machine while the articles are stationary, the heating apparatus comprising:
- a plurality of electrical resistance heating elements disposed adjacent to an article curing station to radiate heat to an article in said station;
- power control means for varying the level of power applied to said heating elements, said power control means operating at a first predetermined high power level in excess of that required to attain an operating temperature for raising the temperature of said heating elements toward the operating temperature and at a second predetermined lower power level;
- an interval timer which is adjustable to produce an output after a predetermined time of the curing while the article is stationary;
- cycle control means responsive to an article being positioned in said curing station to generate a first control signal to initiate operation of said timer;
- said interval timer being connected to said power control to interrupt power to said heating elements after said predetermined time interval.
- 4. Heating apparatus for curing articles in accordance with claim 3 including temperature responsive means heated by said heating elements to generate a second control signal upon said temperature responsive means attaining a predetermined temperature, said temperature responsive means connected to supply said second control signal to said power control means to switch said power control means to operate at said second predetermined lower power level.
- 5. Heating apparatus for curing articles in accordance with claim 4 wherein said power control means includes a proportional control whereby said lower power level is variable as a percentage of said high power level with a potentiometer circuit.
- 6. Heating apparatus for curing articles in accordance with claim 5 wherein said temperature responsive means includes a relay actuated to produce said second control signal to connect said potentiometer circuit to said proportioned control to provide said lower power level.
- 7. Heating apparatus for curing articles in accordance with claim 3 wherein said machine is a machine for imprinting resin material in the form of designs on clothing articles, said machine having platens which are indexed from printing stations into said curing station, said heating elements being elongated and being disposed in spaced parallel relation to said article supporting platen;
- said heating elements being selectively connectable to said power control means to vary the area of said platen being heated in accordance with the size of the design being cured.
- 8. Heating apparatus for curing articles on an automatically indexing machine in accordance with claim 7 wherein said heating elements are elongated resistance heating elements, housing means for enclosing said heating elements with said housing being open on a side facing said article supporting platen, and fan means circulating cooling air into said housing means and across said platen.
- 9. Apparatus for heat curing ink applied to a substrate comprising:
- a screen printer for printing heat curable ink on each substrate movable sequentially through a series of printing stations at which ink is applied to the substrate;
- a frame;
- electrical resistance heating elements mounted on said frame in proximity to a substrate supported in a curing station to cure said paint;
- control means for supplying electrical power to said heating elements at a first predetermined high level which would raise the heating elements to a temperature in excess of the curing temperature during heat-up of said elements and at a second predetermined lower level suitable for curing after said heating elements have attained a predetermined curing temperature;
- substrate transfer means on the screen printer for moving said substrate from a printing station into said curing station at which the substrate is stationary and, after a predetermined interval of being stationary, moving said substrate out of said curing station;
- an interval timer which is initiated on failure of said substrate transfer means to transfer the stationary article within a predetermined time, said timer being connected to said control means to interrupt power to said heating elements a predetermined time after failure of said transfer means.
- 10. Apparatus for heat curing paint in accordance with claim 9 wherein said control means supplies electrical power continuously at said lower level as long as said transfer means moves said substrate out of said curing station in said predetermined interval, with fan means circulating cooling air between said heating elements and said substrate in the curing station.
- 11. Apparatus for heat curing paint in accordance with claim 10 wherein said control means includes a temperature control having a thermocouple responsive to said heating elements to generate a control signal upon attaining a predetermined temperature, said control means including a power control means responsive to said control signal to switch from supplying electrical power at a said high lever to supplying power at said lower level.
- 12. A method of controlling the heat curing of articles being processed on an automatically indexing screen printing machine comprising:
- providing resistance heating elements for raising articles to a curing temperature at a curing station to which articles are supplied;
- supplying power to said elements at a first high level to raise said elements to a predetermined elevated curing temperature, said first high level being capable of raising the temperature of said elements to substantially above the curing temperature;
- supplying power to said elements at a second preselected lower level after said elements have attained said elevated curing temperature;
- transferring articles into and out of said curing station while maintaining each article stationary in said station for a predetermined curing time interval in which the article is stationary; and
- terminating the application of said second lower level of power responsive to the time an article remains in said curing station exceeding the predetermined time interval.
- 13. A method of controlling the heat curing of articles in accordance with claim 12 including an interval timer to terminate the supply of power in response to said article remaining in said curing station for more than said preselected indexing time.
- 14. A method of controlling the heat curing of articles as set forth in claim 13 including the step of selecting the numbers of said heating elements to be powered during a specific curing cycle.
- 15. A method of controlling the heat curing of articles in accordance with claim 14 wherein initiation of operation of said resistance heating elements caused said power to be supplied at said first high level until said elements have attained said elevated temperature.
- 16. A method of controlling heat curing of articles in accordance with claim 15 wherein said supply of power to said heating elements is controlled by a solid state proportional control operated at full power to supply said first high level of power and having a rheostat selectively set to provide a percent of full power at said second preselected lower level.
- 17. A method of controlling heat curing of articles in accordance with claim 16 wherein the terminating of said second lower level of power is accomplished by a relay controlled by said interval timer which opens the circuit to said proportional control on expiration of said preselected time.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of co-pending U.S. patent application Ser. No. 773,486, filed Oct. 9, 1991, which is hereby incorporated by reference as if fully reproduced herein.
US Referenced Citations (13)
Continuation in Parts (1)
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Number |
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773486 |
Oct 1991 |
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