Large-particle inkjet receiver-charging intermediate member

1. Apparatus for producing a print on a recording medium, comprising:

a) a printhead configured to provide drops of hydrophilic liquid;

b) an intermediate member having a conductive element and a drop-retention layer disposed over the conductive element, the drop-retention layer configured to receive the drops of hydrophilic liquid, the drop-retention layer being formed from a hydrophobic material having a plurality of cells and including an ion donor disposed in one or more of the cells;

c) a controller configured to receive image data for the print and control the printhead and the intermediate member so that a liquid pattern corresponding to the image data is produced in one or more of the cells of the intermediate member, wherein the ion donor in those cells dissolves in the deposited liquid so that the liquid pattern includes ions having respective signs of charge;

d) a transport member configured to bring the recording medium into contact with the liquid pattern on the intermediate member;

e) a backing electrode arranged opposite the positioned recording medium from the intermediate member;

f) a voltage source configured to apply a bias across the recording medium in contact with the liquid pattern using the backing electrode and the conductive element of the intermediate member, so that at least some of the ions of a selected one of the signs of charge move from the liquid pattern to the recording medium and a charge pattern corresponding to the liquid pattern is developed on the recording medium; and

g) a development station configured to apply charged dry ink to the recording medium bearing the charge pattern, so that a dry ink image corresponding to the image data is formed on the recording medium.

2. The apparatus according to claim 1 , wherein:

the liquid pattern includes ions of two signs of charge,

the applied bias moves at least some of the ions of a selected one of the two signs of charge into the recording medium,

and the apparatus further includes a replenisher configured to add replenishment ions of the selected one of the two signs of charge to at least some of the cells of the liquid pattern after the charge pattern is formed on the recording medium.

3. The apparatus according to claim 1 , wherein a replenisher includes a container of an aqueous solution of replenishment ion donor arranged so that the drop-retention layer passes through the container.

4. The apparatus according to claim 1 , further including a dryer configured to remove the liquid pattern from the drop-retention layer after the charge pattern is developed on the recording medium.

5. The apparatus according to claim 4 , further including a replenisher configured to deposit replenishment ion donor in the drop-retention layer after the liquid pattern is removed by the dryer.

6. The apparatus according to claim 1 , wherein the drop-retention layer is arranged so that the received liquid is in indirect mechanical contact with the conductive element.

7. The apparatus according to claim 1 , wherein the drop retention layer is an open-cell foam.

8. The apparatus according to claim 1 , wherein the printhead is a drop-on-demand inkjet printhead.

9. The apparatus according to claim 1 , wherein the printhead is a continuous inkjet printhead.

10. The apparatus according to claim 1 , wherein the dry ink is charged to a sign opposite the selected one of the signs of charge.

11. The apparatus according to claim 1 , wherein the ion donor is a salt, acid, or base.

12. The apparatus according to claim 11 , wherein the ion donor is selected from the group consisting of NaOH, LiOH, KOH, H 3 PO 4 , H 2 PO 4 − , and HPO 4 2− .