A liquid ejection head includes a nozzle for ejecting a droplet of a liquid, a pressure chamber connected to the nozzle, an actuator for changing a volume of the chamber according to a voltage signal, and a drive circuit generating the signal for ejecting n droplets, where n is an integer of 3 or more. The signal includes (n−1) ejection pulses, comprising a first pulse lowering the voltage signal to a first value to expand the chamber and then to a second value to contract the chamber, and a second pulse lowering the voltage signal to the first value and then to a third value higher than the second value. The pulses are input at intervals of 0.8λ to 1.2λ, where λ is a primary natural vibration period of the chamber filled with the liquid.

A flow path switching unit includes a rotary valve configured to rotate, a housing including a contact surface with which the rotary valve comes into contact, and a pressing member configured to press the rotary valve against the contact surface. The housing includes a first flow path that opens to the contact surface, a second flow path that opens to the contact surface, and a third flow path that opens to the contact surface. The rotary valve includes an elastic portion configured to come into contact with the contact surface and including a recessed portion facing the contact surface. The rotary valve is configured to switch between a state in which the recessed portion faces the first flow path and the second flow path, and a state in which the recessed portion faces the first flow path and the third flow path by rotation of the rotary valve.

A liquid discharge apparatus including: a first storage section that stores a liquid; a second storage section that communicates with the first storage section; a supply channel that supplies the liquid from the second storage section to a liquid ejecting head; a collection channel that collects the liquid from the liquid ejecting head to the first storage section; the pressurization section that pressurizes the inside of the second storage section; and a control section, in which the first storage section, the supply channel, the liquid ejecting head, the collection channel, the second storage section, and the communication path form a circulation route, and the control section is configured to execute discharge circulation in which circulation of the liquid is performed while discharging the liquid from the nozzle, and non-discharge circulation in which circulation of the liquid is performed without discharging the liquid from the nozzle.

A method of filling a print head includes drawing a vapor into an empty print head to displace any air in the print head and filling the print head with ink. A method of filling a print head includes connecting a print head to a vacuum pump using a first valve, to a liquid supply using a second valve, and to an ink supply using a third valve, opening the first and second valves, applying vacuum to the print head and liquid supply using the vacuum pump, causing the liquid to generate a vapor that moves into the print head, closing the first valve and the second valve, and opening the third valve to move ink into the print head.

In an example, a selection valve of a fluid supply system is disclosed. The selection valve selectively couples a source of pressurized air to one of first and second fluid supply cartridges, in the fluid supply system, to provide fluid to a printhead, the one of first and second fluid supply cartridges being coupled to the source of pressurized air at a time and other fluid supply cartridge being vented to the atmosphere. The selection valve includes a sleeve to provide interconnections with the source of pressurized air, the first and second fluid supply cartridges, and the atmosphere. Further, the selection valve includes a core disposed rotatably inside the sleeve to selectively couple the one of first and second fluid supply cartridges to the source of pressurized air and the other fluid supply cartridge to the atmosphere for switching the pressurized air between the first and second fluid supply cartridges.

A head unit includes a common passage, at least one recording head, and a joint mechanism. The joint mechanism has a first valve and couples the common passage to the recording head. The first valve includes: a first stopper having a switch member with an insertion hole and an engagement boss projecting from its inner surface, a sliding portion inserted in the insertion hole slidably up and down, and an engagement groove engaged with the engagement boss; and a first sealing member fitted on the first stopper to be in contact with or away from the insertion hole's inner surface. Rotating the switch member to move the first stopper up/down causes the first valve to switch between a closed state, with the first sealing member in contact with the insertion hole's inner surface, and an open state, with the first sealing member away from the insertion hole's inner surface.

A controller includes a second controller that periodically performs a flushing operation of injecting a predetermined amount of ink from a nozzle, a third controller that repeatedly performs the flushing operation until a remaining amount of the ink in a storage chamber after the flushing operation is detected by a detector to be a first amount, a first counter that counts a first operation number of times of the flushing operation, and a fourth controller that performs a first cleaning operation of absorbing a fluid in a sealed space by a suction pump when the first operation number of times counted by the first counter reaches a first threshold value.

An example device in accordance with an aspect of the present disclosure includes a first reservoir for a printable composition, a pump fluidically coupled to the first reservoir and a second reservoir, a sensor, and a controller. The controller is to identify first and second reservoir statuses based on the sensor.

A liquid ejection head includes a pressure chamber, an upstream channel, a downstream channel, a pump, an inflow channel, and a bypass channel. The upstream channel communicates with the pressure chamber to supply the liquid to the pressure chamber. The downstream channel communicates with the pressure chamber. The pump communicates with the upstream channel and the downstream channel to cause the liquid in the downstream channel to flow into the upstream channel. The inflow channel communicates with the upstream channel to cause the liquid to be supplied to the pressure chamber to flow into the upstream channel. The upstream channel and the downstream channel communicate with each other through the bypass channel without the pressure chamber being between the upstream channel and the downstream channel. Part of the liquid flowing from the upstream channel into the bypass channel flows into the pressure chamber through the downstream channel.

A liquid ejection head includes a pressure chamber communicating with an ejection port, an ejection element which ejects the liquid from the port, and a circulation path for the liquid including the chamber. The path includes a supply channel for supplying the liquid to the chamber, a collection channel for collecting the liquid from the chamber, a circulation pump which supplies the collected liquid to the supply channel, and a pressure adjustment unit configured to adjust a pressure on the liquid to be supplied to the supply channel. A pressure P21 on the liquid supplied to the chamber while the pump is stopped, a pressure P22 on the liquid supplied to the chamber while the pump is driven, and a pressure loss ΔP from the adjustment unit to the chamber while the pump is driven satisfy P22>P21 and P22−ΔP<0.