High-speed phase change ink image producing machine having a phase change ink delivery system including particulate solid ink pastilles

1. A high-speed phase change ink image producing machine comprising:

(a) a movable imaging member having an imaging surface;

(b) a printhead system connected to said control subsystem for pixel-wise ejecting drops of melted liquid phase change ink onto said imaging surface to form an image;

(c) a phase change ink delivery system including particulate pastille solid phase change ink for enabling said high-speed phase change in image producing machine to produce images at a rate exceeding 50 prints per minute, said particulate pastille solid phase change ink consisting essentially of (i) sub-granular size particulate pastilles for heating and melting into liquid phase change ink, (ii) each sub-granular size particulate pastille is waxy and melts at less than about 120.degree. C., and (iii) each sub-granular size particulate pastille has a size of one of very fine sand, fine sand, medium sand and coarse sand having a diameter of less than 1 mm on the Wentworth-Udden particle-sizing scale.

2. The high-speed phase change ink image producing machine of claim 1 , wherein each pastille of said sub-granular size particulate pastille includes a relatively small surface area and at least 75% of said small surface area is substantially spherical for increasing the bulk flow rate thereof.

3. The high-speed phase change ink image producing machine of claim 1 , wherein said melting rate is at most 3 seconds per pastille.

4. The high-speed phase change ink image producing machine of claim 1 , wherein said melting rate overall is at least 10 gm/min by weight of pastilles.

5. The high-speed phase change ink image producing machine of claim 1 , further comprising (a) a mixture of a salt and an oxyalkylene compound having a melting point of from about 60 degree C. to about 120 degree C.; (b) a lightfastness component; and (c) a lightfastness antioxidant.

6. The high-speed phase change ink image producing machine of claim 1 , wherein said each sub-granular size particulate pastille is the size of very fine sand having a diameter within a range of 0.0625-0.125 mm on the Wentworth-Udden particle-sizing scale for increasing a melting rate thereof.

7. The high-speed phase change ink image producing machine of claim 1 , wherein said each sub-granular size particulate pastille is the size of fine sand having a diameter within a range of 0.125-0.250 mm on the Wentworth-Udden particle-sizing scale for increasing a melting rate thereof.

8. The high-speed phase change ink image producing machine of claim 1 , wherein said each sub-granular size particulate pastille is the size of fine sand having a diameter within a range of 0.250-0.500 mm on the Wentworth-Udden particle-sizing scale for increasing a melting rate thereof.

9. The high-speed phase change ink image producing machine of claim 1 , wherein said each sub-granular size particulate pastille is the size of fine sand having a diameter within a range of 0.500-1.00 mm on the Wentworth-Udden particle-sizing scale for increasing a melting rate thereof.

10. The high-speed phase change ink image producing machine of claim 2 , wherein at most 25% of said small surface area is substantially flat for increasing the bulk flow rate of said particulate pastilles.