Examples include: a leveling system for a top feeder of a printer, where the top feeder includes a media positioning arrangement. The leveling system has a detector for detecting reflected light and generating a three-dimensional image comprising at least one media positioning region corresponding to the media positioning arrangement on a top sheet of a media stack installed into the top feeder. Also, the leveling system has an actuator configured to adjust heights of different points of the bottom of the media stack. Further, it has a controller for selecting, based on the three-dimensional image, adjustments to the heights for improving leveling of at least one of the at least one media positioning region; and controlling the actuator to implement the adjustments.

When duplex printing non-rectangular sheets of printable media, the sheets require proper registration to prevent misalignment of front and back images. This is ensured by: determining relative orientations of three different edges of a sheet being transported towards print station on a first pass; registering the sheet on the first pass by aligning one of the edges with respect to a predetermined alignment direction; printing a first image on a first side of the registered sheet; flipping the sheet on a second pass; registering the flipped sheet by aligning one of the edges with respect to a predetermined alignment direction; and printing a second image on a second side of the registered, flipped sheet aligned with the first image based on the determined relative orientations.

When duplex printing non-rectangular sheets of printable media, the sheets require proper registration to prevent misalignment of front and back images. This is ensured by: determining relative orientations of three different edges of a sheet being transported towards print station on a first pass; registering the sheet on the first pass by aligning one of the edges with respect to a predetermined alignment direction; printing a first image on a first side of the registered sheet; flipping the sheet on a second pass; registering the flipped sheet by aligning one of the edges with respect to a predetermined alignment direction; and printing a second image on a second side of the registered, flipped sheet aligned with the first image based on the determined relative orientations.

An ultrasonic device includes an ultrasonic element having an ultrasonic wave transmission and reception surface that performs at least one of transmission of ultrasonic waves and reception of ultrasonic waves, and a housing that houses the ultrasonic element, wherein the housing has a reflection surface that reflects the ultrasonic waves, a waveguide that propagates the ultrasonic waves, and an opening provided at one end of the waveguide, through which the ultrasonic waves pass, and a length of the waveguide is longer than a width of the waveguide.

An ultrasonic device includes an ultrasonic element having an ultrasonic wave transmission and reception surface that performs at least one of transmission of ultrasonic waves and reception of ultrasonic waves, and a housing that houses the ultrasonic element, wherein the housing has a reflection surface that reflects the ultrasonic waves, a waveguide that propagates the ultrasonic waves, and an opening provided at one end of the waveguide, through which the ultrasonic waves pass, and a length of the waveguide is longer than a width of the waveguide.