There is provided an ink jet printer including: an installation case in which a first tank communicating with an atmosphere is to be installed; a second tank; a head communicating with the second tank; a first channel having one end to be communicated with the first tank installed in the installation case and the other end communicating with the second tank; a second channel having one end communicating with an upper part inside the second tank and the other end to be communicated with the first tank installed in the installation case; and a pump which is disposed in the second channel and which is configured to move a fluid at least from the one end of the second channel to the other end of the second channel.

A base board includes a board and a controller mounted on the board. A controller is configured to receive signals outputted from a first sensor and a second sensor. A recording head, a case, the first sensor, a maintenance unit, a waste liquid container, the second sensor, and the base board are arranged in an internal space of a housing. The base board has a flat surface extending in a first horizontal direction and in a second horizontal direction. A range occupied by the base board in a vertical direction overlaps each of a range occupied by the first sensor in the vertical direction and a range occupied by the second sensor in the vertical direction. The second horizontal direction is perpendicular to the first horizontal direction. The vertical direction is perpendicular to both the first horizontal direction and the second horizontal direction.

A printing device interface to receive a fluid supply may include a fluid dock arranged on an external surface of a housing of the printing device, the fluid dock further arranged to receive a mechanical interface of a fluid supply wherein the arrangement of the fluid dock on the external surface of the housing enables use of a center of mass and weight of the fluid supply to maintain a mechanical, fluidic, and electrical connection with the fluid supply.

An ink is circulated in a circulation path including a supply sub-tank, a discharge head and a collection sub-tank in a head unit. If the amount of the ink in the head unit decreases, the ink stored in the buffer tank is replenished to the head unit. On the other hand, in a first non-replenishment time during which the ink is not replenished, the ink is circulated through the buffer tank, the collection sub-tank and the supply sub-tank in this order. Thus, a temperature fluctuation of the replenishment ink stored in the buffer tank is suppressed. As a result, even if the ink is replenished to the head unit from the buffer tank, physical properties, particularly a viscosity, of the ink do not largely vary.

A liquid residual-amount detecting device includes an optical sensor having a pair of a light emitting portion and a light receiving portion; and a plurality of liquid cartridges, each having a containing portion, a float disposed in the containing portion, and a light shielding portion displaced on a path that crosses an optical path of detection light in synchronization with displacement of the float, wherein the light shielding portions each having a size such that a light amount of the detection light, which the light receiving portion receives, cannot be made smaller than a predetermined light amount by alone; and wherein when the float is at a highest position, they are disposed to be aligned in a direction crossing the optical path so as to shield the optical path, and the light amount, which the light receiving portion receives, is made smaller than the predetermined light amount.

An ink-jet printing apparatus includes an ink-cartridge mounting unit to which an ink cartridge having a first ink chamber containing ink is to be mounted, and a second ink chamber. The second ink chamber stores ink supplied from the first ink chamber. The ink-jet printing apparatus is configured such that, in a case where the ink cartridge is mounted to the ink-cartridge mounting unit, the second ink chamber can be viewed from outside of the ink-jet printing apparatus. An equation 0.5 L≤d≤1.2 L is satisfied, where d is a length of the second ink chamber, and L is a length of the ink cartridge in a direction in which the ink cartridge is inserted into the ink-jet printing apparatus.

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 system includes: a housing; a cover that is supported by the housing to be movable between a covering position and an opened position; a tank; a reservoir; and a liquid discharging head that is disposed inside the housing and discharges liquid supplied from the tank, wherein the reservoir includes a liquid passage hole; the tank includes a passage tube that extends upward from the tank and is connectable to the liquid passage hole of the reservoir, the cover includes: a first wall that is positioned above the housing at the covering position, and a second wall that extends downward from an edge of the first wall, and when the cover is positioned at the covering position and the reservoir is connected to the tank, an upper end of the reservoir is positioned above a lower end of the second wall.