A printing apparatus comprises: a print head comprising, for each of a plurality of types of inks, an ejection opening and pressure chamber, and configured to perform printing operation by ejecting the ink from the ejection opening; a circulation unit capable of circulating the ink of each ink type; a determination unit configured to determine an accumulated time for which a first type of ink is circulated by the circulation unit in the printing operation using the first type of ink and not using a second type of ink different from the first type of ink; and a control unit configured to perform control based on the determined accumulated time to cause the circulation unit to circulate at least the second type of ink among the plurality of types of inks in a case where the accumulated time is longer than a predetermined time.

A system and method upwards ink deposit onto a substrate in existing printing systems. The system provides for multiple orientations of the print head including jetting in the vertical (or generally upwards) direction to mark a substrate. The system allows the ink jetting to be easily integrated into existing converting or printing processes without the need to add auxiliary web transporting devices such as a turn bar since the print head is jetting the pigment-based ink sets vertically as illustrated in the document provided. To jet vertically the ink viscosity needs to be closely controlled utilizing in line ink heating systems that are deployed throughout the ink supply circuit. The system measures the difference between meniscus and pressure with a predetermined amount of heat applied to the system using in line/integrated heating devices in order to accomplish a vertical jet at speed.

Provided are a liquid jetting structure and its applications. The liquid jetting structure includes: a nozzle substrate on which a nozzle for jetting a liquid is formed; and a flow passage substrate on which a liquid flow passage communicating with the nozzle is formed, in which a first layer, a second layer, and a liquid-repellent layer are provided in this order on a jetting surface of the nozzle substrate, the first layer and the second layer are provided in this order on an inner wall of the liquid flow passage, the first layer is a layer containing at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide, and the second layer is a layer containing at least one selected from the group consisting of SiO.sub.2, SiC, SiN, SiCN, and SiON.

Provided are a liquid jetting structure and its applications. The liquid jetting structure includes: a nozzle substrate on which a nozzle for jetting a liquid is formed; and a flow passage substrate on which a liquid flow passage communicating with the nozzle is formed, in which a first layer, a second layer, and a liquid-repellent layer are provided in this order on a jetting surface of the nozzle substrate, the first layer and the second layer are provided in this order on an inner wall of the liquid flow passage, the first layer is a layer containing at least one selected from the group consisting of tantalum oxide, zirconium oxide, titanium oxide, and hafnium oxide, and the second layer is a layer containing at least one selected from the group consisting of SiO.sub.2, SiC, SiN, SiCN, and SiON.

A pressure control unit includes a liquid storage chamber, an inflow port that allows the liquid to flow therein, and an outflow port that allows the liquid to flow out thereof, the pressure control unit controlling pressure of the liquid, wherein at least part of an outer wall of the liquid storage chamber is formed of a flexible film, a pressing plate that presses the flexible film, an urging member that urges the pressing plate, and a valve that opens and closes the outflow port. The pressing plate moves in a direction of expanding the liquid storage chamber, whereby the valve in contact with the pressing plate moves and makes a valve opening degree of the outflow port high. A range of motion of the valve when making the valve opening degree of the outflow port high is limited by a member other than the pressing plate.

An example printhead includes a circulation channel having an inlet for receiving a fluid and an outlet for expelling the fluid, a first nozzle fluidically coupled to the circulation channel, the first nozzle being operable at a first absolute pressure, and a second nozzle fluidically coupled to the circulation channel, the second nozzle being operable at a second absolute pressure, the absolute second pressure being lower than the first absolute pressure. The absolute pressure in the circulation channel decreases as the fluid flows from the inlet to the outlet, and the first nozzle is positioned closer to the inlet of the circulation channel than the second nozzle.

An example printhead includes a circulation channel having an inlet for receiving a fluid and an outlet for expelling the fluid, a first nozzle fluidically coupled to the circulation channel, the first nozzle being operable at a first absolute pressure, and a second nozzle fluidically coupled to the circulation channel, the second nozzle being operable at a second absolute pressure, the absolute second pressure being lower than the first absolute pressure. The absolute pressure in the circulation channel decreases as the fluid flows from the inlet to the outlet, and the first nozzle is positioned closer to the inlet of the circulation channel than the second nozzle.

A recording apparatus includes a recording head configured to discharge a liquid, a first liquid reservoir unit configured to store the liquid to be supplied to the recording head, a liquid supply port configured to supply the liquid stored in the first liquid reservoir unit into the recording head, a liquid supply path connecting the first liquid reservoir unit and the liquid supply port, a second reservoir unit, in the recording head, configured to store the liquid supplied from the liquid supply port, and a holding unit configured to hold the liquid supplied from the second reservoir unit, in the recording head, wherein the second reservoir unit includes an opening provided upward in a direction of a gravitational force with respect to the liquid supply port and is configured to supply the liquid to the holding unit, when the recording head is in a posture of performing recording.

A recording apparatus includes a recording head configured to discharge a liquid, a first liquid reservoir unit configured to store the liquid to be supplied to the recording head, a liquid supply port configured to supply the liquid stored in the first liquid reservoir unit into the recording head, a liquid supply path connecting the first liquid reservoir unit and the liquid supply port, a second reservoir unit, in the recording head, configured to store the liquid supplied from the liquid supply port, and a holding unit configured to hold the liquid supplied from the second reservoir unit, in the recording head, wherein the second reservoir unit includes an opening provided upward in a direction of a gravitational force with respect to the liquid supply port and is configured to supply the liquid to the holding unit, when the recording head is in a posture of performing recording.

In some examples, an apparatus can include a valve body including a recirculation inlet path and a recirculation outlet path, a piston assembly located in the valve body, and a recirculation cavity between the valve body and the piston assembly, where print material is to be circulated through the recirculation cavity via the recirculation inlet path and the recirculation outlet path.