Claims
- 1. A sheet-fed printing system, comprising:a source of printing medium; a support frame at least partially enclosing the sheet-fed printing system; a transfer element rotatably supported by the support frame; a source for directing ultraviolet radiant energy at a substrate being printed with the pointing medium, the source substantially disposed within the support frame and positioned proximate the transfer element, some of the radiant energy absorbed by the transfer element thereby raising a temperature of the transfer element; and a cooling unit configured for generating and directing a cooled airflow onto the transfer element, the cooled airflow maintaining the transfer element within an effective temperature range such that the substrate being printed distorts less than an allowable substrate distortion limit, the cooled airflow substantially generated from air at least partially present within the support frame and previously cooled by the cooling unit.
- 2. The printing system of claim 1, in which the transfer element is selected from a transfer cylinder and an impression cylinder.
- 3. The printing system of claim 1, in which the allowable substrate distortion limit is {fraction (1/64)} inch.
- 4. The printing system of claim 1, in which the allowable substrate distortion limit is {fraction (1/100)} inch.
- 5. The printing system of claim 1, in which the allowable substrate distortion limit is {fraction (1/1000)} inch.
- 6. The printing system of claim 1, in which the transfer element temperature is maintained between an ambient air dew point temperature and 120 degrees F.
- 7. The printing system of claim 1, in which the transfer element temperature is maintained between a temperature slightly above an ambient air dew point temperature and 120 degrees F.
- 8. The printing system of claim 1, in which the transfer element temperature is maintained between 60 degrees F. and 120 degrees F.
- 9. The printing system of claim 1, in which the transfer element temperature is maintained between 90 degrees F. and 95 degrees F.
- 10. The printing system of claim 1, in which the airflow has a temperature between slightly above the freezing point of water and 120 degrees F.
- 11. The printing system of claim 1, in which the airflow has a temperature between 40 degrees F. and 75 degrees F.
- 12. The printing system of claim 1, in which the airflow has a temperature between 50 degrees F. and 55 degrees F.
- 13. The printing system of claim 1, the cooling unit comprising:at least one fan; and at least one cooling coil conveying a coolant and positioned to cool air directed by the fan at the transfer element.
- 14. The printing system of claim 13, in which the coolant has a temperature less than the transfer element temperature.
- 15. The printing system of claim 13, in which the coolant has a temperature between 32 degrees F. and 120 degrees F.
- 16. The printing system of claim 13, in which the coolant has a temperature between 32 degrees F. and 40 degrees F.
- 17. The printing system of claim 13, in which the coolant comprises a chilled liquid.
- 18. The printing system of claim 17, in which the chilled liquid comprises water.
- 19. The printing system of claim 13, in which the coolant comprises a compressible gas.
- 20. The printing system of claim 13, further comprising a temperature sensor in electrical communication with the fan, the temperature sensor measuring the transfer element temperature.
- 21. The printing system of claim 20, in which the temperature sensor comprises an infrared, noncontact sensor.
- 22. The printing system of claim 20, further comprising a control unit and a pump or valve, the control unit in electrical communication with the sensor, the pump or valve, and the fan and activating the fan and the pump or valve when the transfer element is heated to a designated temperature.
- 23. The system of claim 22, in which the control unit is configured so that the designated temperature can be set by an attendant.
- 24. A process for maintaining an operating sheet-fed printer transfer element heated by a source of ultraviolet energy within a designated temperature range, the transfer element at least partially enclosed and supported by a support frame, the process comprising:providing a cooling unit comprising at least one fan and a cooling coil; and directing an airflow at the transfer element, the airflow cooled by the cooling coil and generated by the fan, at least a portion of the airflow generated from air previously cooled by the cooling unit.
- 25. The process of claim 24, in which the cooling coil conveys chilled water.
- 26. The process of claim 24, in which the coil conveys a compressible gas.
- 27. The process of claim 24, in which the airflow is directed in response to a temperature sensor reading.
- 28. The process of claim 27, in which a control unit is in electrical communication with the temperature sensor, the fan and a palm or valve circulating coolant through the cooling coil and in which the airflow is initiated by the control unit in response to a reading from the temperature sensor.
- 29. The process of claim 24, in which the airflow is directed in response to a reading from an infrared, noncontact sensor.
- 30. A process of installing a cooling system for a sheet-fed printer transfer element heated by ultraviolet radiation, the transfer element supported by a support frame, die support face at least partially enclosing the transfer element, the process comprising:providing a cooling unit with at least one cooling coil, a fan, and a pump, the fan generating an airflow from air previously cooled by the cooling unit within the support frame, the airflow cooled by the cooling coil, the pump circulating a cooling fluid through the cooling coil; and positioning the cooling unit so as to direct the airflow at the transfer element.
- 31. The process of claim 30, further comprising electrically connecting a thermal sensor to the fan and the pump.
- 32. The process of claim 30, further comprising electrically connecting a noncontact, infrared sensor to the fan and the pump.
- 33. The process of claim 32, further comprising electrically connecting a control unit to the sensor, the fan, and the pump.
- 34. The process of claim 30, in which the provided pump circulates chilled water through the cooling coil.
- 35. The process of claim 30, in which the provided pump includes a compressor compressing a compressible gas to be circulated through the coil.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C.§119 (e) to, and hereby incorporates by reference, U.S. Provisional Application No. 60/162,594, filed Oct. 29, 1999.
US Referenced Citations (26)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 652 104 |
Feb 1995 |
EP |
0 638 418 |
May 1995 |
EP |
Non-Patent Literature Citations (1)
Entry |
European Search Report dated Mar. 22, 2001. |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/162594 |
Oct 1999 |
US |