PRINT SYSTEM WITH VOLUME SUBSTANTIALLY VOID OF LIQUID

• US 20180001656A1
• Filed: 01/29/2015
• Published: 01/04/2018
• Est. Priority Date: 01/29/2015
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: SWIER, Kevin E., OTIS, David R.
• Granted Patent: US 10,449,777 B2
• Time in Patent Office: Days
• CPC Class Codes: B41J 2/175 Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17506 Refilling of the cartridge
• CPC Class Codes: B41J 2/17556 Means for regulating the pressure in the cartridge
• CPC Class Codes: B41J 2/19 for removing air bubbles

Abstract

A print system or a method to apply a negative pressure to a substantially dry volume through at least one vent.

Claims

1. A method of starting usage of a print system, wherein

a negative pressure is applied to at least one gas-filled volume through at least one vent;

while a pressure in the volume decreases, the gas is drawn out through the vent and print liquid is moved into the volume; and

the volume is filled with the liquid so that one side of the vent is covered with the liquid whereby the pressure in the volume increases up to a point where it becomes relatively steady.

2. The method of claim 1 wherein the vent is liquid impermeable and gas permeable in a direction out of the volume to allow gas but not liquid to be drawn out of the volume, at least in a wet condition of the vent and within an operational pressure range applied to the vent of approximately −

6 to −

120 water column.

3. The method of claim 1 wherein during startup a negative pressure is refreshed during a relatively long accumulated time span, and after startup, during routine usage, a negative pressure is refreshed during a relatively short accumulated time span.

4. The method of claim 1 wherein

the volume is part of a print bar assembly that is substantially completely filled with air at start-up, and

by applying the negative pressure at least approximately 20 cubic centimeters of air is drawn out of the printbar assembly, through the vent, and replaced by print liquid, within approximately 2 minutes.

5. The method of claim 1 wherein

the volume comprises a filter,

a first vent fluidically connects to the volume upstream of the filter,

a second vent fluidically connects to the volume downstream of the filter, and

the negative pressure is applied through both vents.

6. The method of claim 5 wherein a negative pressure exceeds a wetted vent bubble pressure but does not exceed a wetted nozzle bubble pressure.

7. The method of claim 1 wherein during the startup routine nozzles are capped with a cap assembly or with a capping liquid.

8. A print system, comprising

a volume substantially void of liquid that includes at least one vent to vent gas out, and a nozzle array;

a negative pressure pump assembly to apply a negative pressure to the vent that exceeds a wetted vent bubble pressure of the vent; and

a controller to

initiate a startup routine by instructing the pump assembly to actively refresh negative pressure during a relatively long accumulated time span; and

after completing the startup routine, instruct the pump assembly to refresh negative pressure during a relatively short accumulated time span.

9. The print system of claim 8 comprising a filter in the volume, wherein the at least one vent comprises,

a first vent upstream of the filter fluidically connected to the regulator chamber, and

a second vent downstream of the filter.

10. The print system of claim 9 wherein the filter and vent are wet.

11. The print system of claim 9 wherein the negative pressure is between approximately 6 and approximately 40 water column.

12. The print system of claim 8 comprising

a filter in the volume downstream of the vent;

a cap assembly to cap the nozzles during the startup routine; and

a liquid pump to pump liquid towards the nozzles;

wherein

the negative pressure pump assembly is to draw air through the vent and through the filter during the startup routine, and

the negative pressure is at least approximately 60 water column.

13. The print system of claim 8 wherein the negative pressure pump assembly includes a vacuum reservoir to apply the negative pressure to the at least one vent.

14. The print system of claim 13 wherein the negative pressure pump assembly includes a solenoid valve between the pump and the vacuum reservoir, and the controller is to instruct the solenoid valve to set negative pressure refresh cycles of the vacuum reservoir.

15. The method of claim 8 wherein the vent includes a liquid philic part on a wet side and a liquid phobic part on a dry side.