In some examples, a printing press includes a printing unit with at least four nozzle bars, each including a print head. At least one nozzle bar has a printing position and at least one service position. For instance, in a first service position, the at least one nozzle bar has a first distance to the transport path of a printing substrate, and in a second service position the at least one nozzle bar has a second distance to the transport path. The printing unit includes at least one cleaning device and/or cleaning system that is selectively arranged in an area between the at least one nozzle bar and the transport path. The at least one service position may be arranged in vertical direction above the printing position, and the second distance of the second service position of the nozzle bar may be less than in the first service position.

An example printing apparatus is illustrated. The printing apparatus includes a print engine assembly. The print engine assembly further includes a bottom chassis portion. The print engine assembly also includes a top chassis portion. The print engine assembly also includes a print head positioned within the top chassis portion. The print engine assembly also includes a plurality of offset pins coupled to the print head, where the plurality of offset pins abuts the bottom chassis portion, and where the plurality of offset pins enables the print head to be positioned at a predetermined distance from the bottom chassis portion.

Printhead carriers and adapters are disclosed. An example disclosed print mechanism includes an adapter to simultaneously couple a printhead assembly to both a logic circuit of a media processing device and a power source of the media processing device; a printhead carrier coupled to the adapter; and wherein a first connection, between data input connector and the logic circuit, and a second connection, between the power input connector and the power source, are maintained when the printhead assembly is removed from the print mechanism.

Printhead carriers and adapters are disclosed. An example disclosed print mechanism includes an adapter to simultaneously couple a printhead assembly to both a logic circuit of a media processing device and a power source of the media processing device; a printhead carrier coupled to the adapter; and wherein a first connection, between data input connector and the logic circuit, and a second connection, between the power input connector and the power source, are maintained when the printhead assembly is removed from the print mechanism.

One example of a fluid ejection system includes a plurality of fluid ejection devices, a corresponding plurality of indicators, an operator interface, and a controller. Each indicator is on a corresponding fluid ejection device. The operator interface is to select a fluid ejection device. The controller is to turn on the corresponding indicator for the selected fluid ejection device.

One example of a fluid ejection system includes a plurality of fluid ejection devices, a corresponding plurality of indicators, an operator interface, and a controller. Each indicator is on a corresponding fluid ejection device. The operator interface is to select a fluid ejection device. The controller is to turn on the corresponding indicator for the selected fluid ejection device.

A single pass inkjet printer that utilizes a modular printing system with one or more self-contained printing modules, where each printing module is easy to remove and replace from a large printing machine, thus resulting in an overall system that is easy to service and maintain Each module is a self-contained printer including an ink supply, printhead drive electronics, and printhead assembly in order to provide one color or fluid of inkjet printing capability. Each module includes a precise three-point compliant self-aligning mount system to obtain accurate printhead positioning, and a unique integrated printhead tending system that includes a compact movable vacuum knife for cleaning the printheads, and a printhead capping station for sealing and protecting the printheads from the ambient environment when not in use.

A single pass inkjet printer that utilizes a modular printing system with one or more self-contained printing modules, where each printing module is easy to remove and replace from a large printing machine, thus resulting in an overall system that is easy to service and maintain Each module is a self-contained printer including an ink supply, printhead drive electronics, and printhead assembly in order to provide one color or fluid of inkjet printing capability. Each module includes a precise three-point compliant self-aligning mount system to obtain accurate printhead positioning, and a unique integrated printhead tending system that includes a compact movable vacuum knife for cleaning the printheads, and a printhead capping station for sealing and protecting the printheads from the ambient environment when not in use.

A liquid discharge head includes a head body, a cover, a rib, and a sealer. The head body discharges liquid. The head body includes a frame. The cover is mounted on the frame of the head body. The rib is disposed at the frame along a peripheral surface of the cover. The sealer is disposed between the peripheral surface of the cover and a peripheral surface of the rib.

A single-pass inkjet printer contains a track for guiding a printing medium in the Y direction, a plurality of printing head modules which are arranged one behind the other in the Y direction and a respective plurality of printing heads which extends in the X direction transversely over the track, and a printing region in which the printing head modules can be mounted in a respective printing position in an upright manner in the Z direction and in a reversibly insertable and removable manner along the Z direction. The single-pass inkjet printer further contains a storage region in which a number of printing head modules are mounted in a storage position in an upright manner substantially in the Z direction and in a reversibly insertable and removable manner along the Z direction. The printing heads of printing head modules set in the storage position are received in a protective cover.