In one example, an apparatus is described, which includes a platen locating the print medium, at least one printhead for marking on the print medium, a carriage holding the at least one printhead, a sensor at least partially mounted to the carriage to measure a printhead-to-platen spacing (PPS) along scanning axis during scanning, and an integrated circuit including a dynamic compensation module and a PPS analysis module to delay firing of printing fluid drops from the at least one printhead to compensate platen defects based on the measured PPS.

In one example, an apparatus is described, which includes a platen locating the print medium, at least one printhead for marking on the print medium, a carriage holding the at least one printhead, a sensor at least partially mounted to the carriage to measure a printhead-to-platen spacing (PPS) along scanning axis during scanning, and an integrated circuit including a dynamic compensation module and a PPS analysis module to delay firing of printing fluid drops from the at least one printhead to compensate platen defects based on the measured PPS.

An image recording apparatus, including: a main body; an image recorder; a sheet supporter movable between an opposed position and a retracted position; a cap movable between a contact position and a distant position; a distance-defining member movable between a first position and a second position and configured to define a distance between an upper surface of a sheet and a lower surface of the recorder, the first position being a position where the member partially overlaps a region of the cap at the contact position, the second position being a position where at least a part of the member does not overlap the region; and a controller to control the cap to move from the distant position to the contact position after the supporter has been moved from the opposed position to the retracted position and the member has been moved from the first position to the second position.

An image recording apparatus, including: a main body; an image recorder; a sheet supporter movable between an opposed position and a retracted position; a cap movable between a contact position and a distant position; a distance-defining member movable between a first position and a second position and configured to define a distance between an upper surface of a sheet and a lower surface of the recorder, the first position being a position where the member partially overlaps a region of the cap at the contact position, the second position being a position where at least a part of the member does not overlap the region; and a controller to control the cap to move from the distant position to the contact position after the supporter has been moved from the opposed position to the retracted position and the member has been moved from the first position to the second position.

Both end parts of a cord are fixed to a maintenance mounting frame, and an intermediate part of the cord is laid on a first body-side rotating member, a head-side rotating member and a second body-side rotating member. Here, when a motor is driven, the movement restriction of the cord is released and a movement of a head mounting frame is restricted, whereby only the maintenance mounting frame moves together with a maintenance part while the movement of the head mounting frame is restricted. Further, when the motor is driven, a movement of the cord is restricted and the movement restriction of the head mounting frame is released, whereby only the head mounting frame moves together with a discharge head while a movement of the maintenance part is restricted.

An image forming apparatus includes a conveyance part, a head unit, a distance changing part, three blocks and three pins. The distance changing part moves the head unit between a printing position where a printing operation is performed and a retreat position separated away from the conveyance part farther than the printing position. The three blocks are provided in one of the conveyance part and the head unit at intervals in the conveyance direction and a width direction crossing the conveyance direction. The three pins are provided in the other of the conveyance part and the head unit at positions facing the three blocks. Each of the three blocks has a positioning groove having a pair of inclined surfaces. The pins come into two-point contact with the inclined surfaces of the blocks in a state where the head unit is positioned in the printing position.

An image forming apparatus includes a conveyance part, a head unit, a distance changing part, three blocks and three pins. The distance changing part moves the head unit between a printing position where a printing operation is performed and a retreat position separated away from the conveyance part farther than the printing position. The three blocks are provided in one of the conveyance part and the head unit at intervals in the conveyance direction and a width direction crossing the conveyance direction. The three pins are provided in the other of the conveyance part and the head unit at positions facing the three blocks. Each of the three blocks has a positioning groove having a pair of inclined surfaces. The pins come into two-point contact with the inclined surfaces of the blocks in a state where the head unit is positioned in the printing position.

A printer includes a supporting table to support a recording medium, a recording head located above the supporting table to eject ink toward the supporting table, a first contact detector located above the supporting table and lower than the recording head, an oscillator to vibrate the first contact detector, and a vibration detector to detect vibration of the first contact detector and transmit a signal corresponding to the detected vibration. The printer stores a threshold related to the vibration of the first contact detector and determines that an object has come into contact with the first contact detector when an amount of the vibration detected by the vibration detector is equal to the threshold or less.

A printer includes a supporting table to support a recording medium, a recording head located above the supporting table to eject ink toward the supporting table, a first contact detector located above the supporting table and lower than the recording head, an oscillator to vibrate the first contact detector, and a vibration detector to detect vibration of the first contact detector and transmit a signal corresponding to the detected vibration. The printer stores a threshold related to the vibration of the first contact detector and determines that an object has come into contact with the first contact detector when an amount of the vibration detected by the vibration detector is equal to the threshold or less.

Mechanisms for adjusting the position of one or more print heads at an extremely fine resolution (e.g., less than 10 μm) are described herein. The adjustment mechanisms include a differential screw and an indexing wheel through which the differential screw extends. One threaded segment of the differential screw is connected to a threaded feature of a flexible body that is coupled to the print head(s), while another threaded segment of the differential screw is connected to a threaded feature of a rigid body that is coupled to a printer assembly. As the indexing wheel and differential screw rotate, the space between the flexible body and the rigid body changes based on the difference between the pitches of the threaded segments. The adjustment mechanisms described herein utilize the accurate, consistent motion of the flexible body upon experiencing pressure to effect predictable changes in the position of the print head(s).