A liquid ejection head including: an ejection port portion with an ejection port configured to eject liquid in an ejection direction; a pressure chamber that includes therein an energy-generating element to eject the liquid from the ejection port; a supply channel configured to supply the liquid to the pressure chamber; a collecting channel configured to collect the liquid from the pressure chamber; and a pump configured to cause the liquid in the collecting channel to flow into the supply channel, wherein F.sub.ratio is 1.4 or less.

Provided are a liquid ejection head and a liquid ejection apparatus capable of reducing a decrease in productivity. To this end, a liquid sending unit is provided which is provided outside a first channel for a flow from a supply channel to a collection channel via pressure chambers and which is capable of sending a liquid from a first pressure control chamber to a second pressure control chamber.

In an ink jet printing method for discharging ink from a liquid discharge head, the ink contains titanium oxide having a precipitation velocity of 1.010.sup.11 m/s or more based on a Stokes equation in the ink, the liquid discharge head comprises a discharge port, a pressure chamber, an energy-generating element, an upstream flow channel for supplying a liquid to the pressure chamber, a downstream flow channel communicating with the pressure chamber, and a pump communicating with the upstream flow channel and the downstream flow channel and forming a circulation path in which the ink circulates in an order of the upstream flow channel, pressure chamber, downstream flow channel, and upstream flow channel, the liquid discharge head is configured so as to perform reciprocal scan, and a scanning velocity in a region where the liquid discharge head scans at a constant velocity is higher than the precipitation velocity.

An embodiment of the present invention is an inkjet printing apparatus including: a tank unit formed partly of a flexible film and having a tank storing a liquid and a gas chamber, which abut each other with the flexible film therebetween; a liquid ejection head that ejects the liquid supplied from the tank through a supply path and has a bubble accumulation chamber in which bubbles inside the head accumulate and a bubble removal chamber adjoining the bubble accumulation chamber; a pump that pressurizes an inside of the gas chamber; and an air channel linking the pump and the bubble removal chamber. The pump pressurizes the inside of the gas chamber to thereby pressurize the tank and supply the liquid from the tank to the head through the supply path, and the pump performs depressurization to thereby depressurize an inside of the bubble removal chamber through the air channel.

A method of cleaning a converter, the method including the steps of: providing a heating unit for heating a cleaning fluid; providing a ring main for continuous circulation of heated cleaning fluid around the ring main; connecting the heating unit to the ring main; connecting the ring main to the converter to enable delivery of heated cleaning fluid to the converter; and providing a controllable cleaning fluid valve for delivery of a heated cleaning fluid, and providing a controllable rinsing fluid valve for delivery of a rinsing fluid; providing a controller for controlled delivery of a sequence of the rinsing fluid and the heated cleaning fluid to the converter upon recognition of a rinsing fluid delivery condition and a heated cleaning fluid delivery condition, respectively.

An inkjet recording device includes a pump, an ink flow path, an on-off valve, a motor, a one-way clutch and a closing mechanism. The motor drives the pump when rotated in a first direction. The one-way clutch is coupled to the motor, and is rotated when the motor is rotated in a second direction opposite to the first direction. The closing mechanism is coupled to the one-way clutch, and closes the on-off valve in an open state as the one-way clutch is rotated so as to stop the distribution of the ink between the pump and the on-off valve.