An inking system for use in transferring ink to a flexographic printing plate in a flexographic printing system includes an anilox member having an ink transfer zone located between first and second recessed bearing contact zones. A radius of the recessed bearing contact zones is less than a radius of the ink transfer zone by at least 0.100 inches. An ink tray includes a floor and first and second end walls. Bearings are mounted outside of the end walls which engage with the first and second bearing contact zones, respectively, thereby positioning the ink tray assembly in a specified position relative to the anilox member. Upper edges of the end walls extend into the recessed bearing contact zones.

A printing system to hold printing material comprises a sealing interface to seal a container with respect to a printing chamber volume of the printing system, the container to hold the printing material. The printing system comprises a lifting system to move the container between a first position in which the container is to be lifted and a second position at which the container is lifted and contacts the seal so as to seal the container. The lifting system is to non-hyperstatically constrain the container.

An example of apparatus including an attachment assembly to mate a liquid supply with a reservoir is provided. The apparatus includes an outlet port disposed on the attachment assembly, wherein the outlet port is to dispense liquid from the liquid supply to a receiving port of the reservoir. The apparatus includes a main vent port disposed on the attachment assembly, wherein the main vent port is to receive air from the reservoir as the liquid enters the reservoir. The apparatus includes a plug disposed on the attachment assembly, wherein the plug is to seal a secondary vent when the attachment assembly is mated with the reservoir, and wherein the plug is to break a seal with the secondary vent prior to detachment of the attachment assembly to recover the liquid from the attachment assembly.

A sheet-fed simultaneous printing machine has two directly interacting collecting cylinders with respective axes of rotation. An axial plane contains these axes of rotation. A reference plane contains such an axis of rotation of this type and has a horizontal surface normal. The intersection angle between the axial plane and the reference plane is max 0.5°. The sheet-fed simultaneous sheet printing unit has exactly four plate cylinders, of which two are arranged such that they directly interact with the first and two are arranged to such that they directly interact with the second collector cylinder. An inking unit with a respective ink supply is arranged in each plate cylinder and a supply sectional plane is determined for each ink supply, which intersects this ink supply and which also contains the axis of rotation of the corresponding plate cylinder. An intersection angle between the reference plane and a supply sectional plane of the respective ink supply is max 35°. A sheet-fed machine comprises at least one sheet-fed printing unit of this type, as well as a sheet-fed printing unit having two directly interacting impression cylinders. An intersection angle between the axial plane on one side and the reference plane on the other side is max 45°.

An example printing device may comprise an indicator to convey information to a user, a print substance reservoir to house a print substance, where the print substance reservoir is communicatively coupled to a fill port, a sensor to determine when a refill container is connected to the fill port, a processing resource, and a non-transitory machine-readable medium storing instructions executable by the processing resource to transmit signals to the indicator responsive to an indication that the sensor has detected the refill container connected to the fill port, where the signals correspond to the information to be conveyed by the indicator, and authenticate the refill container.

An example printing device may comprise an indicator to convey information to a user, a print substance reservoir to house a print substance, where the print substance reservoir is communicatively coupled to a fill port, a sensor to determine when a refill container is connected to the fill port, a processing resource, and a non-transitory machine-readable medium storing instructions executable by the processing resource to transmit signals to the indicator responsive to an indication that the sensor has detected the refill container connected to the fill port, where the signals correspond to the information to be conveyed by the indicator, and authenticate the refill container.

An example of an apparatus is provided. The apparatus includes a feeder tank to provide print fluid to a nozzle. The feeder tank is disposed below the nozzle to maintain a backpressure. The apparatus also includes a vent port to vent the feeder tank to atmosphere. The apparatus further includes an overflow chamber in fluidic communication with the feeder tank. The overflow chamber is disposed below the nozzle. In addition, the apparatus includes a return channel disposed on the overflow chamber to allow print fluid in the overflow chamber to return to the feeder tank.

An example of an apparatus is provided. The apparatus includes a feeder tank to provide print fluid to a nozzle. The feeder tank is disposed below the nozzle to maintain a backpressure. The apparatus also includes a vent port to vent the feeder tank to atmosphere. The apparatus further includes an overflow chamber in fluidic communication with the feeder tank. The overflow chamber is disposed below the nozzle. In addition, the apparatus includes a return channel disposed on the overflow chamber to allow print fluid in the overflow chamber to return to the feeder tank.

An example fluid handling system for a printer is disclosed. In an implementation, the fluid handling system includes a first compartment, a second compartment, and a fluid port. The first compartment is fluidly coupled to the second compartment through the fluid port and the first compartment, second compartment and fluid port are disposable within a printer. In addition, the fluid handling system includes a barrier disposed within the fluid port. The barrier separates the fluid port into a first channel and a second channel, wherein the barrier is movable within the fluid port.

An example fluid handling system for a printer is disclosed. In an implementation, the fluid handling system includes a first compartment, a second compartment, and a fluid port. The first compartment is fluidly coupled to the second compartment through the fluid port and the first compartment, second compartment and fluid port are disposable within a printer. In addition, the fluid handling system includes a barrier disposed within the fluid port. The barrier separates the fluid port into a first channel and a second channel, wherein the barrier is movable within the fluid port.