Patent Description:
At certain times, such as upon completion of a service contract or at the end of life of the printer, excess printing agent left in the reservoir may be recovered from the printer. Printing agent may be recovered from the printer by connecting a printing agent recovery vessel to the printer and pumping the printing agent into the recovery vessel.

<CIT> describes an automatic ink interconnect between a print cartridge and a carriage. <CIT> and <CIT> disclose further relevant prior art for the present invention.

Unused printing agent stored in an onboard reservoir of a printer may be recovered via a recovery operation. A recovery operation may involve connecting a printing agent recovery vessel to the printer and pumping printing agent from the reservoir into the recovery vessel. If the recovery vessel is suddenly removed from the printer during the recovery operation, built-up pressure in the line from the reservoir to the recovery vessel may cause printing agent to leak out from the printer.

Such leakage may be reduced, mitigated, or prevented by maintaining pressure in the onboard reservoir below atmospheric pressure during the recovery operation. With the onboard reservoir below atmospheric pressure, unrecovered printing agent in transit toward the recovery vessel may be drawn back toward the reservoir by negative pressure rather than allowed to leak out of the printer. The negative pressure at the reservoir is maintained by a negative pressure element such as a vacuum pump or other element capable of maintaining negative pressure in the reservoir.

Thus, a printing apparatus includes a reservoir to contain a printing agent. The printing apparatus further includes a recovery port to receive connection of a recovery vessel and to communicate flow of the printing agent from the reservoir to the recovery vessel during a recovery operation. The printing apparatus further includes a recovery pump to pump the printing agent from the reservoir through the recovery port to the recovery vessel during the recovery operation. The printing apparatus may further include a negative pressure element, such as a vacuum pump, to maintain pressure in the reservoir below atmospheric pressure, during the recovery operation. Thus, when the recovery vessel is removed from the recovery port during the recovery operation, unrecovered printing agent is drawn away from the recovery port, and leakage of printing agent from the recovery port may thereby be reduced, mitigated, or prevented, and the printing agent may be retained in the printing apparatus.

The negative pressure element may include a vacuum pump, a relief valve, or another element which is to maintain pressure in the reservoir such that unrecovered printing agent is retained in the printing apparatus when the recovery vessel is removed during the recovery operation. The printing apparatus includes a controller to control the negative pressure element and may include an electromechanical switch which is to signal to the controller when the recovery vessel is received at the recovery port.

<FIG> is a schematic diagram of such an example printing apparatus <NUM>. The printing apparatus <NUM> includes a reservoir <NUM> to contain a printing agent <NUM>. The printing agent <NUM> may include any printable fluid, such as printer ink, packaging ink, 3D printer ink, biological sample, chemical, or other liquid.

The printing apparatus <NUM> further includes a recovery port <NUM> to receive connection of a recovery vessel and to communicate flow of the printing agent <NUM> from the reservoir <NUM> to the recovery vessel during a recovery operation. A recovery operation may involve pumping the printing agent <NUM> to a recovery vessel connected to the recovery port <NUM>, and may be performed when recess printing agent <NUM> is to be recovered from the printing apparatus <NUM> for another use, such as such as upon completion of a service contract or at the end of life of a printer of which the printing apparatus <NUM> is a part.

The printing apparatus <NUM> further includes a recovery pump <NUM> to pump the printing agent <NUM> from the reservoir <NUM> through the recovery port <NUM> to the recovery vessel during the recovery operation.

Further, the recovery port <NUM> may include an inlet/outlet which is in a closed state when not connected with a recovery vessel, and in an open state when connected with a recovery vessel to allow pumping of printing agent <NUM> therethrough. For example, the recovery port <NUM> may mate by mechanical connection with the recovery vessel or associated tubing to open the inlet/outlet of the recovery port <NUM> and establish communication between the recovery port <NUM> and the recovery vessel. Further, the recovery port <NUM> may include a closing mechanism which tends to close the inlet/outlet upon removal of the recovery vessel.

The closing mechanism of the recovery port <NUM> may not close the inlet/outlet quickly enough or with enough power to prevent leakage of pressurized printing agent <NUM> when a recovery vessel is suddenly removed from the recovery port <NUM> during a recover operation. Thus, the printing apparatus <NUM> further includes a vacuum pump <NUM> at the reservoir <NUM> to reduce pressure in the reservoir <NUM> to below atmospheric pressure during the recovery operation to draw unrecovered printing agent <NUM> away from the recovery port <NUM> when the recovery vessel is removed from the recovery port <NUM>. The recovery operation may proceed with the reservoir <NUM> at a negative pressure.

<FIG> is a schematic diagram showing an example recovery vessel <NUM> being removed from the printing apparatus <NUM> of <FIG> during a recovery operation. The recovery vessel <NUM> is initially connected to the recovery port <NUM>, and the recovery pump <NUM> is initially pumping printing agent <NUM> into the recovery vessel <NUM> in a recovery direction <NUM>. Further, the vacuum pump <NUM> is maintaining negative pressure in the reservoir <NUM>.

When the recovery vessel <NUM> is removed from the recovery port <NUM>, negative pressure in the reservoir <NUM> draws the printing agent <NUM> away from the recovery port <NUM> in the reverse recovery direction <NUM>, and printing agent <NUM> is thereby retained in the printing apparatus <NUM>.

<FIG> is a schematic diagram of another example printing apparatus <NUM>. The printing apparatus <NUM> may be similar to the printing apparatus <NUM> of <FIG>, with like elements numbered in a "<NUM>" series rather than a "<NUM>" series, and thus, includes a reservoir <NUM> to contain a printing agent <NUM>, a recovery port <NUM>, a recovery pump <NUM>, and may include a vacuum pump <NUM>. For further description of the above elements, description of the printing apparatus <NUM> of <FIG> may be referenced.

The printing apparatus <NUM> may further include a pressure regulating element <NUM> to regulate pressure in the reservoir <NUM> during a recovery operation. The pressure regulating element <NUM> may include a pressure regulator or a tuned valve to regulate pressure in the reservoir <NUM> as the vacuum pump <NUM> works to reduce pressure in the reservoir <NUM>. The pressure regulating element <NUM> may prevent the vacuum pump <NUM> from reducing pressure in the reservoir <NUM> below a predetermined threshold, such as a threshold which bounds the normal operating range of the vacuum pump <NUM>.

The printing apparatus <NUM> may further include a print head <NUM> to print the printing agent <NUM> onto a substrate. The print head <NUM> may be part of a print bar. The print head <NUM> may be connected to the reservoir <NUM> by a recirculation loop <NUM> which includes tubing between the reservoir <NUM> and the print head <NUM> that allows for recirculation of printing agent <NUM> between the print head <NUM> and the reservoir <NUM>. Further, the recovery pump <NUM> may operate as a recirculation pump to recirculate the printing agent <NUM> with the print head <NUM> during a printing operation. The recovery pump <NUM> may therefore communicate forward flow of printing agent <NUM> during a printing operation and backflow of printing agent <NUM> when printing agent <NUM> is drawn into the reservoir <NUM> by negative pressure.

The printing apparatus <NUM> may further include a recovery line <NUM> to communicate flow of the printing agent <NUM> from the reservoir <NUM> to the recovery port <NUM> during the recovery operation. The recovery line <NUM> may branch from the recirculation loop <NUM>. The recovery line <NUM> may include a drain valve <NUM> to block flow through the recovery line <NUM> during normal operation or a print operation and to permit flow through the recovery line <NUM> during a recovery operation.

The printing apparatus <NUM> may further include a supply pump <NUM> located on a supply line <NUM> to pump supply printing agent from a supply vessel to the reservoir <NUM> during a filling operation. The supply pump <NUM> may communicate flow of unrecovered printing agent into the reservoir <NUM> when a recovery vessel is removed from the recovery port <NUM> during a recovery operation. Thus, when a recovery vessel is removed from the recovery port <NUM> during a recovery operation, printing agent <NUM> may be withdrawn into the reservoir <NUM> through the recovery pump <NUM> and the supply pump <NUM>.

<FIG> is a schematic diagram of another example printing apparatus <NUM>. The printing apparatus <NUM> may be similar to the printing apparatus <NUM> of <FIG>, with like elements numbered in a "<NUM>" series rather than a "<NUM>" series, and thus, may include a reservoir <NUM> to contain a printing agent <NUM>, a recovery port <NUM> to receive connection of a recovery vessel and to communicate flow of the printing agent <NUM> from the reservoir <NUM> to the recovery vessel during a recovery operation, and a recovery pump <NUM> to pump the printing agent <NUM> from the reservoir <NUM> through the recovery port <NUM> to the recovery vessel during the recovery operation. For further description of the above elements, description of the printing apparatus <NUM> of <FIG> may be referenced.

The printing apparatus <NUM> further includes a controller <NUM> to cooperate with a negative pressure element <NUM> at the reservoir <NUM> to maintain a negative pressure in the reservoir <NUM> during the recovery operation. The negative pressure is to draw unrecovered printing agent <NUM> away from the recovery port <NUM> when the recovery vessel is removed from the recovery port <NUM>.

The negative pressure element <NUM> may include a vacuum pump, a relief valve, or another element to maintain negative pressure at the reservoir <NUM> during a recovery operation. Where the negative pressure element includes a relief valve, the relief valve may be closed during a recovery operation, thereby allowing the recovery pump <NUM> to generate backpressure in the reservoir <NUM> as printing agent <NUM> is recovered into the recovery vessel.

The controller <NUM> may initiate the recovery pump <NUM> to pump the printing agent when a recovery vessel is received at the recovery port <NUM>. Further, the controller <NUM> may shut off the recovery pump <NUM> when a recovery vessel is removed from the recovery port <NUM>, thereby reducing flow of printing agent <NUM> out of the recovery port <NUM>.

The printing apparatus <NUM> may include an electromechanical switch <NUM> in communication with the controller <NUM> which may signal to the controller <NUM> when the recovery vessel is received at the recovery port <NUM>. Further, the controller <NUM> may initiate the negative pressure element <NUM> to develop negative pressure in the reservoir <NUM> when a recovery vessel is received at the recovery port <NUM>. For example, where the negative pressure element <NUM> includes a vacuum pump, the controller <NUM> may control the vacuum pump to reduce pressure in the reservoir <NUM> when the recovery vessel is received at the recovery port <NUM>.

In some examples, the controller may initiate the negative pressure element <NUM> to develop negative pressure in the reservoir <NUM> before the recovery pump <NUM> is initiated to pump the printing agent <NUM>. Thus, negative pressure may be built at the reservoir <NUM> prior to pumping of the printing agent <NUM> pursuant to the recovery operation so that negative pressure draws the printing agent <NUM> away from the recovery port <NUM> even when a recovery vessel is removed from the recovery port <NUM> early in the recovery operation.

<FIG> is a schematic diagram of another example printing apparatus <NUM>. The printing apparatus <NUM> may be similar to the printing apparatus <NUM> of <FIG>, with like elements numbered in a "<NUM>" series rather than a "<NUM>" series, and thus, includes a reservoir <NUM>-<NUM> to contain a printing agent <NUM>-<NUM> and a recovery pump <NUM>-<NUM>. For further description of the above elements, description of the printing apparatus <NUM> of <FIG> may be referenced.

The printing apparatus <NUM> may include a plurality of reservoirs to contain a plurality of printing agents. For example, the printing apparatus <NUM> may include a first reservoir <NUM>-<NUM> to contain a first printing agent <NUM>-<NUM>, a second reservoir <NUM>-<NUM> to contain a second printing agent <NUM>-<NUM>, and a third reservoir <NUM>-<NUM> to contain a third printing agent <NUM>-<NUM>. Other quantities of reservoirs and printing agents are contemplated. Further, it is contemplated that one printing agent, such as the second printing agent <NUM>-<NUM>, may be different from another printing agent, such as the first printing agent <NUM>-<NUM>. For example, where the printing apparatus <NUM> is part of an inkjet printer which prints according to the CMYK color model, the printing apparatus <NUM> may include four reservoirs to contain cyan, magenta, yellow, and black inks.

The printing apparatus <NUM> may include a plurality of recovery lines each including a recovery pump corresponding to each reservoir. For example, the printing apparatus <NUM> may include a first recovery line <NUM>-<NUM> to communicate flow of the first printing agent <NUM>-<NUM> from the first reservoir <NUM>-<NUM> to a recovery vessel, where the first recovery line <NUM>-<NUM> includes a first recovery pump <NUM>-<NUM> to pump the first printing agent <NUM>-<NUM> to the recovery vessel during a recovery operation. The printing apparatus <NUM> may further include a second recovery line <NUM>-<NUM> to communicate flow of the second printing agent <NUM>-<NUM> from the second reservoir <NUM>-<NUM> to the recovery vessel, where the second recovery line <NUM>-<NUM> includes a second recovery pump <NUM>-<NUM> to pump the second printing agent <NUM>-<NUM> to the recovery vessel during the recovery operation. The printing apparatus <NUM> may further include a third recovery line <NUM>-<NUM> to communicate flow of the third printing agent <NUM>-<NUM> from the third reservoir <NUM>-<NUM> to the recovery vessel, where the third recovery line <NUM>-<NUM> includes a third recovery pump <NUM>-<NUM> to pump the third printing agent <NUM>-<NUM> to the recovery vessel during the recovery operation.

The printing apparatus <NUM> may further include a negative pressure element <NUM> which is common to each of the reservoirs. The negative pressure element <NUM> may maintain negative pressure in the reservoirs to retract printing agent toward the reservoirs when the recovery operation is interrupted by removal of the recovery vessel. For example, the negative pressure element <NUM> may maintain negative pressure in the first reservoir <NUM>-<NUM> and the second reservoir <NUM>-<NUM> during the recovery operation to retract the first printing agent <NUM>-<NUM> from the first recovery line <NUM>-<NUM> toward the first reservoir <NUM>-<NUM> when the recovery operation is interrupted and to retract the second printing agent <NUM>-<NUM> from the second recovery line <NUM>-<NUM> to the second reservoir <NUM>-<NUM> when the recovery operation is interrupted. The negative pressure element <NUM> may be similar to the negative pressure element <NUM> of the printing apparatus <NUM> of <FIG>, and thus, for further description thereof, reference may be had to the negative pressure element <NUM>.

The printing apparatus <NUM> may include additional elements from the printing apparatuses <NUM>, <NUM>, <NUM>, and <NUM>. For example, the recovery lines <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, may feed into a recovery port which may be similar to the recovery port <NUM> of the printing apparatus <NUM> of <FIG>. For further description of the recovery port, reference may be had to the recovery port <NUM> of <FIG>. Further, the negative pressure element <NUM> may be controlled by a controller, which may be similar to the controller <NUM> of the printing apparatus <NUM> of <FIG>. For further description of the controller, reference may be had to the controller <NUM> of <FIG>. As yet another example, the first reservoir <NUM>-<NUM> may include a first tuned valve to regulate pressure in the first reservoir <NUM>-<NUM>, the second reservoir <NUM>-<NUM> may include a second tuned valve to regulate pressure in the second reservoir <NUM>-<NUM>, and the negative pressure element <NUM> may include a vacuum pump.

<FIG> is a schematic diagram of an example printer <NUM>. The printer <NUM> includes a reservoir <NUM> to contain a printing agent, a recovery port <NUM> to receive connection of a recovery vessel and to communicate flow of the printing agent from the reservoir <NUM> to the recovery vessel during a recovery operation. The printer <NUM> further includes a recovery pump <NUM> to pump the printing agent from the reservoir through the recovery port <NUM> to the recovery vessel during the recovery operation, and a print bar <NUM> which includes a print head for printing the printing agent during a printing operation.

The reservoir <NUM> includes a negative pressure element <NUM> to maintain negative pressure in the reservoir <NUM> to draw the printing agent toward the reservoir <NUM> to retain printing agent in the printer <NUM> when a recovery operation is interrupted by removal of a recovery vessel from the recovery port <NUM>. The negative pressure element <NUM> may be similar to the negative pressure element <NUM> of the printing apparatus <NUM> of <FIG>, and thus, for further description thereof, reference may be had to the negative pressure element <NUM>.

In other applications, a printing apparatus similar to the printing apparatuses <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be incorporated into a package label printer, a biological sample depositor, a 3D printer, or any other printer which prints a printable fluid, and the printing agent <NUM> may be any printable fluid, such as printer ink, packaging ink, 3D printing ink, biological sample, chemical, or other liquid.

Claim 1:
A printing apparatus (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a reservoir (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to contain a printing agent (<NUM>, <NUM>, <NUM>, <NUM>);
a recovery port (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to receive connection of a recovery vessel (<NUM>) and to communicate flow of the printing agent (<NUM>, <NUM>, <NUM>, <NUM>) from the reservoir (<NUM>,<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to the recovery vessel (<NUM>) during a recovery operation;
a recovery pump (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to pump the printing agent (<NUM>, <NUM>, <NUM>, <NUM>) from the reservoir (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) through the recovery port (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to the recovery vessel (<NUM>) during the recovery operation;
a controller (<NUM>); and
characterized in that the printing apparatus (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) further comprises:
a negative pressure element (<NUM>, <NUM>, <NUM>) at the reservoir (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
wherein the controller (<NUM>) configured to cooperate with the negative pressure element (<NUM>, <NUM>, <NUM>) at the reservoir (<NUM>,<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to maintain a negative pressure in the reservoir (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) during the recovery operation to draw unrecovered printing agent (<NUM>, <NUM>, <NUM>, <NUM>) away from the recovery port (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) when the recovery vessel (<NUM>) is removed from the recovery port (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>).