Printing system with compact transfer roller

1. A compact motorized transfer roller for a printer, comprising:

a cylindrical body having two ends, an outer surface and an interior space, wherein each of said ends is supported by low friction bearings carried by a pair of cooperating end caps, and a first end carries an internal gear; and

a motor located in the interior space, said motor driving the internal gear for rotating the outer surface and advancing print media;

wherein the outer surface is adapted to carry ink and make a printing impression on the print media.

2. The transfer roller of claim 1 , wherein:

the motor is a stepper motor.

3. The transfer roller of claim 1 , wherein:

the motor drives the internal gear through an intermediate drive train.

4. The transfer roller of claim 3 , wherein:

the drive train is a reducing gear assembly.

5. The transfer roller of claim 4 , wherein:

the assembly further comprises a worm gear carried by an output shaft of the motor, the worm gear cooperating with one or more reduction gears.

6. The transfer roller of claim 1 , wherein:

the transfer roller is coated with titanium nitride.

7. The transfer roller of claim 1 , further comprising:

a page width inkjet printhead which ejects ink onto the body.

8. The transfer roller of claim 1 , further comprising:

a page-width cleaning sponge contacting the transfer roller and adapted to clean the transfer roller after it has printed onto the sheet.

9. The transfer roller of claim 8 , further comprising:

a page-width wiper, contacting the transfer roller and located between the sponge and the ink ejecting area.

10. The transfer roller of claim 1 , further comprising:

a second transfer roller, being a similar motorized transfer roller located on an opposite side of a media path of the printer;

the transfer roller and the second transfer roller adapted to print, simultaneously on opposite sides of a sheet in the path.

11. The transfer roller of claim 10 , wherein:

each transfer roller further comprises a page-width cleaning sponge adapted to clean ink from the transfer roller after it has printed onto the sheet.

12. The transfer roller of claim 11 , wherein:

each transfer roller further comprises a page-width wiper, contacting the transfer roller and located between the sponge and an ink ejecting area of a printhead.

13. The transfer roller of claim 1 , in combination with a pick-up roller which is adapted to feed a sheet to the transfer roller, the pick up roller having a molding which acts in conjunction with a sensor to position the pick up roller into a parked position which allows a paper tray of the printer to be withdrawn without touching the pick up roller.

14. The transfer roller of claim 1 , in combination with an optical sensor mounted in the printer for finding the start of a sheet and engaging the motor accordingly.

15. A printer having a transfer roller according to claim 1 , and further comprising:

a media tray for a stack of media and an output slot;

a generally linear media path extending between the tray and the output slot;

the transfer roller being located between the tray and the slot and adapted to print an image on a sheet delivered from the tray.

16. The printer of claim 15 , further comprising:

a page width inkjet printhead which ejects ink onto the body.

17. A printer having two transfer rollers according to claim 1 , and further comprising:

a media tray for a stack of media and an output slot;

a generally linear media path extending between the tray and the output slot;

the transfer rollers being located between the tray and the slot and adapted to print an image on both sides of a sheet delivered from the tray.

18. The printer of claim 17 , further comprising:

two page width inkjet printheads which each ejects ink onto a body of a different transfer roller.