A print apparatus is disclosed. In some examples, the print apparatus comprises a print head to deposit print agent onto a substrate; a detector to detect a fiducial; a first light source to back-illuminate the substrate, such that light from the first light source is to be detected by the detector through the substrate; and processing apparatus. The processing apparatus is to operate the print head to deposit print agent to form a first fiducial on a first side of the substrate, the first fiducial comprising a shape of a first colour and having a first dimension, and a background of print agent of a second, different colour, wherein the first dimension of the shape does not exceed a corresponding dimension of the background; operate the print head to deposit print agent to form a second fiducial on a second, opposite side of the substrate, the second fiducial comprising an inverted version of the shape of the first colour; operate the first light source to back-illuminate the substrate; operate the detector to detect the first and second fiducials; and determine whether the first fiducial is aligned with the second fiducial. A method and a machine-readable medium are also disclosed.

A print apparatus is disclosed. In some examples, the print apparatus comprises a print head to deposit print agent onto a substrate; a detector to detect a fiducial; a first light source to back-illuminate the substrate, such that light from the first light source is to be detected by the detector through the substrate; and processing apparatus. The processing apparatus is to operate the print head to deposit print agent to form a first fiducial on a first side of the substrate, the first fiducial comprising a shape of a first colour and having a first dimension, and a background of print agent of a second, different colour, wherein the first dimension of the shape does not exceed a corresponding dimension of the background; operate the print head to deposit print agent to form a second fiducial on a second, opposite side of the substrate, the second fiducial comprising an inverted version of the shape of the first colour; operate the first light source to back-illuminate the substrate; operate the detector to detect the first and second fiducials; and determine whether the first fiducial is aligned with the second fiducial. A method and a machine-readable medium are also disclosed.

In an example of the disclosure, a web media is advanced through a printer during a printing operation, Tractor-feed holes in a tractor-feed lane of the web media are detected utilizing a sensor and counted as the web media advances. When the count of tractor-feed holes reaches a target tractor-feed hole n, a fiducial detection period is started wherein a sensor is utilized to detect a fiducial. A printing adjustment is determined based upon a time or time period that the fiducial is detected during the fiducial detection period.

A printing platform includes a printing engine with one or more printheads arranged such that the ink drops are jetted vertically upwards against the action of gravity; and a substrate transportation system where the normal to the surface in contact with the substrate is parallel and with opposite direction to the travelling direction of the jetted ink drops. It is necessary to counteract the weight of the substrate during the printing process to avoid it from falling under the action of gravity. This is achieved through any of a mechanical element that interferes with the falling of the substrate and that keeps it in place; or a system that generates adhesion forces between the element that transmits the motion to the substrate, typically a conveyor belt, and the substrate through the action of electrostatic forces, an air pressure differential between both faces of the substrate, or any other suitable mechanism.

A printing platform includes a printing engine with one or more printheads arranged such that the ink drops are jetted vertically upwards against the action of gravity; and a substrate transportation system where the normal to the surface in contact with the substrate is parallel and with opposite direction to the travelling direction of the jetted ink drops. It is necessary to counteract the weight of the substrate during the printing process to avoid it from falling under the action of gravity. This is achieved through any of a mechanical element that interferes with the falling of the substrate and that keeps it in place; or a system that generates adhesion forces between the element that transmits the motion to the substrate, typically a conveyor belt, and the substrate through the action of electrostatic forces, an air pressure differential between both faces of the substrate, or any other suitable mechanism.

In one example, an aerosol control system for a printer includes an air knife to discharge a sheet of air into a flow of aerosol along a moving print substrate web and a vacuum near the air knife to suck up aerosol from the flow simultaneously with the air knife discharging air into the flow.

A print apparatus includes a first printing device arranged to print a first image on a first side of a print target; and a second printing device arranged to print a second image on a second side of the print target, wherein the printing capability of the print apparatus on the first side of the print target is different to the printing capability of the print apparatus on the second side of the print target.

A print apparatus includes a first printing device arranged to print a first image on a first side of a print target; and a second printing device arranged to print a second image on a second side of the print target, wherein the printing capability of the print apparatus on the first side of the print target is different to the printing capability of the print apparatus on the second side of the print target.

A recording device has: a recording head configured to perform recording on a medium; a medium storage below the recording head configured to store the medium to be recoded; a supply path comprising a first curved supply path curved so as to be convex upward and transporting the medium fed out of the medium storage in a reversed direction via the first curved supply path; and a reversing path comprising a second curved path curved so as to be convex downward and transporting the recorded medium into a direction including a vertically upward component via second curved path from a direction including a vertically downward component; wherein the supply path joins the reversing path, and the first curved path and the second curved path overlap when viewed horizontally.

A recording device has: a recording head configured to perform recording on a medium; a medium storage below the recording head configured to store the medium to be recoded; a supply path comprising a first curved supply path curved so as to be convex upward and transporting the medium fed out of the medium storage in a reversed direction via the first curved supply path; and a reversing path comprising a second curved path curved so as to be convex downward and transporting the recorded medium into a direction including a vertically upward component via second curved path from a direction including a vertically downward component; wherein the supply path joins the reversing path, and the first curved path and the second curved path overlap when viewed horizontally.