A liquid cartridge configured to be inserted in a frontward direction to a printer includes: a housing; a liquid supply portion; a circuit board; a plate; and a detection portion. The circuit board includes an electrode group facing upward in an upright posture of the liquid cartridge. The electrode group includes a first electrode, a second electrode, and a third electrode for grounding. The first to third electrodes are arrayed in a lateral direction crossing the frontward direction and a gravitational direction such that the third electrode is positioned between the first and second electrodes. In the upright posture of the liquid cartridge, the plate and the detection portion are respectively positioned upward and rearward relative to the circuit board. Each of the third electrode and an upper portion of the plate is positioned a datum plane extending in the frontward direction and in the gravitational direction.

There is provided a technique that enables correct detection of the remaining amount of liquid such as ink. A liquid ejection apparatus has a liquid ejection head which ejects a supplied liquid, a storage unit which stores a liquid to be supplied to the liquid ejection head, a pivot member which is immersed in a liquid stored in the storage unit and is pivotally movable according to an amount of the liquid, and a detection unit which detects the amount of the liquid using the pivot member, wherein at least one of a specific gravity and size of the pivot member differs according to a specific gravity of a liquid stored in the storage unit.

There is provided a technique that enables correct detection of the remaining amount of liquid such as ink. A liquid ejection apparatus has a liquid ejection head which ejects a supplied liquid, a storage unit which stores a liquid to be supplied to the liquid ejection head, a pivot member which is immersed in a liquid stored in the storage unit and is pivotally movable according to an amount of the liquid, and a detection unit which detects the amount of the liquid using the pivot member, wherein a pivot position of the pivot member differs according to a specific gravity of a liquid stored in the storage unit.

Provided is an inkjet printing apparatus comprising: a print head that ejects ink; a tank that contains ink to be supplied to the print head; a floating body that floats on the liquid surface of the ink inside the tank; and an electrode pin that detects the level of the liquid surface inside the tank. The floating body includes an opening portion in which to insert the electrode pin, and a perimeter of the opening portion protrudes from a top surface side of the floating body.

Industrial printing systems, including systems and techniques relating to drop-on-demand (DOD) inkjet printing systems include an apparatus including: a receptacle defining a hold chamber to receive ink, the receptacle including a first portion configured to hold a first quantity of ink, and a second portion that is smaller than the first portion and configured to hold a second quantity of ink, the second portion including a first heat conducting surface, and a second heat conducting surface offset from the first heat conducting surface by a distance determined in accordance with a melting point of the ink, the second heat conducting surface defining a barrier between the first portion and the second portion and including at least one opening configured to allow flow of the ink from the first portion to the second portion; and at least one heating element configured to heat the receptacle.

An image forming apparatus, having a cartridge detachably attached to the image forming apparatus and including a first compartment configured to store a colorant, a container configured to be connected with the cartridge and including a second compartment configured to store the colorant flowing from the cartridge, and a display configured to display a first object indicating a first remainder amount and a second object indicating a second remainder amount in a single screen, is provided. The first remainder amount is a remainder amount of the colorant stored in the first compartment, and the second remainder amount is a remainder amount of the colorant stored in the second compartment.

A liquid discharge device includes: a tank including a second liquid chamber connectable to a cartridge having a first liquid chamber storing a liquid; a head; and a controller configured to: discharge ink from the head based on a recording instruction; receive a second signal from a liquid level sensor when a position of the liquid level in the second liquid chamber is less than a predetermined position after the ink is discharged based on the recording instruction; after receiving the second signal, determine whether the cartridge is installed in an installation case; based on determining that the cartridge is installed in the installation case after receiving the second signal from the liquid level sensor, accept a maintenance process; and based on receiving the first signal from the liquid level sensor, perform the maintenance process.

Disclosed herein is a print head maintenance assembly, a printing device and a method of controlling a print head maintenance assembly in a printing device. The print head maintenance assembly comprises a maintenance cartridge comprising a positioning flag, wherein the maintenance cartridge is movable along a maintenance path in a direction of movement; and a sensor to detect the positioning flag to determine the position of the maintenance cartridge along the maintenance path.

An image forming apparatus, having a first container with a first compartment, a second container with a second compartment, a recorder, a display, and a controller, is provided. The controller controls the display to display a first screen and a second screen. The first screen contains a first object having a form that reflects an amount of a colorant in the first compartment and a second object having a form that reflects an amount of the colorant in the second compartment. The second screen contains a third object having a form that reflects one of the amount of the colorant in the first compartment, the amount of the colorant in the second compartment, and a total amount of the colorant in the first compartment and the second compartment.

A cartridge for a printing system comprises a receptacle to receive waste printing material from the printing system, a floater to change its position based on a varying filling level of the waste printing material in the receptacle, and a flag mechanically coupled to the floater, wherein a position of the flag depends on the position of the floater and indicates, outside of the receptacle, the filling level.