The invention relates to a method for controlling the ink quality of an ink jet printer, during printing, the printer comprising at least one ink reservoir (11) and a solvent or diluted ink reservoir (12), a print head (50) and a supply circuit for sending ink and/or solvent to the print head, method in which: a correction volume of solvent, or diluted ink, to add to the ink to compensate a variation in viscosity of the latter is estimated; and a plurality of elementary quantities of solvent, or diluted ink, separated by ink, is sent to the print head, each of a volume comprised between 0.1 cm.sup.3 and 5 cm.sup.3, the sum of the elementary quantities of solvent, or diluted ink, being substantially equal to the correction volume to add.

An liquid circulation device comprises a liquid casing, a gas replenishing section and a liquid replenishing section. The liquid casing retains liquid to be supplied to a liquid ejection section for ejecting the liquid and includes a liquid chamber connected with the liquid ejection section in such a manner that the liquid can be circulated therebetween. The ink circulation device increases pressure inside of the liquid casing by replenishing the gas to the liquid casing with the gas replenishing section and replenishing the liquid to the liquid casing with the liquid replenishing section, and meets a relation (ΔP1*(d1)̂2/L1)/(ΔP2*(d2)̂2/L2)>μ1/μ2.

An liquid circulation device comprises a liquid casing, a gas replenishing section and a liquid replenishing section. The liquid casing retains liquid to be supplied to a liquid ejection section for ejecting the liquid and includes a liquid chamber connected with the liquid ejection section in such a manner that the liquid can be circulated therebetween. The ink circulation device increases pressure inside of the liquid casing by replenishing the gas to the liquid casing with the gas replenishing section and replenishing the liquid to the liquid casing with the liquid replenishing section, and meets a relation (ΔP1*(d1)̂2/L1)/(ΔP2*(d2)̂2/L2)>μ1/μ2.

A technique of reducing the possibility that a liquid remains in a buffer chamber is provided. There is provided a liquid supply device configured to supply a liquid to a liquid ejection head. The liquid supply device comprises a liquid containing chamber configured to contain the liquid; an air communication path configured to include a first connection portion at one end that is connected with the liquid containing chamber and an air outlet port at the other end that is open to the atmosphere; and a buffer chamber provided in the middle of the air communication path. The air communication path includes a connection path that is located on a downstream side of the buffer chamber in the air communication path in a flow direction of a fluid from the air outlet port toward the liquid containing chamber and is configured to include a second connection portion at an upstream end connected with the buffer chamber. When the first connection portion is exposed to the liquid in the liquid containing chamber, the second connection portion is placed in a lower area in a vertical direction of the buffer chamber.

A gas-liquid separator includes a casing with a cylindrical chamber inside, a gas-liquid 2-phase inlet pipe which is attached to a wall of the casing and connected to the chamber, a gas outlet pipe for discharging the gas of a gas-liquid mixture flowing into the chamber, and the gas-liquid 2-phase outlet pipe for discharging the liquid as a most part of the gas-liquid mixture flowing into the chamber. A gap is formed around the gas-liquid outlet pipe in the chamber for separating the mixture into liquid and gas using the surface tension and suction force. The gas-liquid separator is installed in the inkjet recording apparatus, especially in the print head. The print head is filled with the solvent gas so as to be suctioned from the gutter to reduce the solvent consumption.

A gas-liquid separator includes a casing with a cylindrical chamber inside, a gas-liquid 2-phase inlet pipe which is attached to a wall of the casing and connected to the chamber, a gas outlet pipe for discharging the gas of a gas-liquid mixture flowing into the chamber, and the gas-liquid 2-phase outlet pipe for discharging the liquid as a most part of the gas-liquid mixture flowing into the chamber. A gap is formed around the gas-liquid outlet pipe in the chamber for separating the mixture into liquid and gas using the surface tension and suction force. The gas-liquid separator is installed in the inkjet recording apparatus, especially in the print head. The print head is filled with the solvent gas so as to be suctioned from the gutter to reduce the solvent consumption.

When printing on the same printing object with multiple print nozzles in the past, consideration was not given to cases in which the time relationships of the set times and times-to-be-printed become mismatched between the respective print items of the print nozzles. To solve said problem, the present invention is an inkjet printer for printing on a conveyed printing object and having multiple print nozzles, multiple auxiliary control units for controlling the printing performed by the multiple print nozzles, and a common main control unit connected to the multiple auxiliary control units via communication means. The main control unit is configured to be equipped with: an extracting function for extracting the time relationship of the set times and the time relationship of the times-to-be-printed between the items to be printed by the respective print nozzles of the multiple print nozzles; and a revising function for revising the print data so as to preserve the time relationship of the set times.

A waste liquid box management method sets a type of ink to be contained in a container, for a waste liquid box that includes a coupling portion coupled to a printer, the container containing ink discharged from the printer via the coupling portion, and a storage unit. The waste liquid box management method individually allocates different storage regions, in the storage unit, to a plurality of ink types, writes predetermined type specification data into a selected storage region, that is the storage region allocated to the ink type to be contained in the container, and inhibits writing to the storage region other than the selected storage region in a state in which data other than the type specification data is stored therein.

The liquid ejection apparatus includes a circulation unit configured to circulate a liquid along a circulation passage extending from a liquid supply source to the liquid supply source through a liquid ejection head. Further, the liquid ejection apparatus includes a deaeration unit configured to perform a deaeration operation of decreasing a dissolved gas amount of the liquid, a recovery unit configured to recover ejection performance of an ejection opening, and a control unit configured to control an operation of driving the circulation unit and the deaeration unit. The control unit starts the deaeration operation and circulates the liquid having been deaerated by the deaeration operation inside a circulation path after the recovery operation and before an initial printing operation after the recovery operation.

The liquid ejection apparatus includes a circulation unit configured to circulate a liquid along a circulation passage extending from a liquid supply source to the liquid supply source through a liquid ejection head. Further, the liquid ejection apparatus includes a deaeration unit configured to perform a deaeration operation of decreasing a dissolved gas amount of the liquid, a recovery unit configured to recover ejection performance of an ejection opening, and a control unit configured to control an operation of driving the circulation unit and the deaeration unit. The control unit starts the deaeration operation and circulates the liquid having been deaerated by the deaeration operation inside a circulation path after the recovery operation and before an initial printing operation after the recovery operation.