Claims

1. A dispensing assembly comprising:a dispensing chamber housing having an inner surface and an outer surface, the inner surface partially defining a dispensing chamber for receiving a quantity of a substance;a temperature control device at least partially surrounding the dispensing chamber housing, the temperature control device for altering a temperature of a substance in the dispensing chamber;a thermal sensor located near the temperature control device, the thermal sensor for reading a temperature near the temperature control device; anda controller for controlling the temperature control device such that the substance in the dispensing chamber is not exposed to elevated temperature nor overexposed to heat.

2. The assembly of claim 1 wherein the controller counts a number of times the temperature control device is activated.

3. The assembly of claim 2 wherein the controller disables a tip segment if the number of times the temperature control device is activated exceeds a set number.

4. The assembly of claim 1 wherein the controller times a period when the temperature control device is activated.

5. The assembly of claim 4 wherein the controller shuts off the temperature control device when the period when the temperature control device is activated exceeds a set period.

6. The assembly of claim 1 further comprising:a switch coupled to the temperature control device.

7. The assembly of claim 6 wherein the controller controls the switch such that a first voltage is applied to the temperature control device until the temperature control device reaches a desired temperature, and a second voltage is applied to the temperature control device thereafter to maintain the temperature control device at the desired temperature.

8. The assembly of claim 1 wherein the temperature control device is a heater comprising a resistive element.

9. An injection assembly comprising:a dispensing chamber housing having an inner surface and an outer surface, the inner surface partially defining a dispensing chamber for receiving a quantity of a substance;a temperature control device at least partially surrounding the dispensing chamber housing, the temperature control device for altering a temperature of a substance in the dispensing chamber;a thermal sensor located near the temperature control device, the thermal sensor for reading a temperature near the temperature control device;a switch coupled to the temperature control device; anda controller for controlling the temperature control device;wherein the controller controls the switch such that a first voltage is applied to the temperature control device until the temperature control device reaches a desired temperature, and a second voltage is applied to the temperature control device thereafter to maintain the temperature control device at the desired temperature.

10. The assembly of claim 9 wherein the controller counts a number of times the temperature control device is activated.

11. The assembly of claim 10 wherein the controller disables a tip segment if the number of times the temperature control device is activated exceeds a set number.

12. The assembly of claim 9 wherein the controller times a period when the temperature control device is activated.

13. The assembly of claim 12 wherein the controller shuts off the temperature control device when the period when the temperature control device is activated exceeds a set period.

14. The assembly of claim 9 wherein the temperature control device is a heater comprising a resistive element.

15. A method of operating a dispensing assembly comprising:checking a count of a number of times a temperature control device has been activated;if the count does not exceed a preset number, incrementing a counter;applying a first voltage across a temperature control device to bring the temperature control device to a desired temperature;after the temperature control device reaches the desired temperature, applying a second voltage across the temperature control device to maintain the temperature control device at the desired temperature;starting a timer to count the amount of time that the temperature control device is activated; andif the amount of time that the temperature control device is activated exceeds a preset amount of time, turning off the temperature control device.

16. The method of claim 15 further comprising:if the count exceeds a preset number, then disabling a tip segment so that an injection cannot be performed.

17. The method of claim 15 wherein applying a first voltage across a temperature control device to bring the temperature control device to a desired temperature further comprises controlling a switch to apply the first voltage.

18. The method of claim 17 wherein applying a second voltage across a temperature control device to bring the temperature control device to a desired temperature further comprises controlling a switch to apply the second voltage.

19. The method of claim 18 wherein starting a timer to count the amount of time that the temperature control device is activated further comprises starting the timer when the switch is controlled to apply the second voltage.

20. The method of claim 15 wherein starting a timer to count the amount of time that the temperature control device is activated further comprises starting the timer after the temperature control device has reached the desired temperature.