A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

A system for in-line treatment of thread for use with a thread consuming device is provided. The system includes a treatment unit including at least a first and a second print head each being configured to dispense one or more coating substances onto the at least one thread when activated; and a control unit configured to determine if a maintenance sequence is to be performed on at least the first print head, and if so schedule said maintenance sequence on at least the first print head. A method is further provided.

A method of operating a printing system includes identifying groups of nozzles of a plurality of nozzles of a printhead device. The method also includes ejecting fluid drops by the printhead device from nozzles thereof and along corresponding firing paths. The method also includes controlling movement of a detector carriage including a plurality of drop detectors of a drop detector array with respect to the printhead device by a control module to align each one of the drop detectors with the respective firing paths corresponding to the respective nozzles at a predetermined time. The method also includes sensing the firing paths corresponding to the nozzles to detect a presence of the fluid drops by the drop detectors such that each one of the drop detectors senses at a same time a respective firing path corresponding to a respective nozzle for a plurality of groups of nozzles.

A method of operating a printing system includes identifying groups of nozzles of a plurality of nozzles of a printhead device. The method also includes ejecting fluid drops by the printhead device from nozzles thereof and along corresponding firing paths. The method also includes controlling movement of a detector carriage including a plurality of drop detectors of a drop detector array with respect to the printhead device by a control module to align each one of the drop detectors with the respective firing paths corresponding to the respective nozzles at a predetermined time. The method also includes sensing the firing paths corresponding to the nozzles to detect a presence of the fluid drops by the drop detectors such that each one of the drop detectors senses at a same time a respective firing path corresponding to a respective nozzle for a plurality of groups of nozzles.

A printing apparatus including a discharge head that performs scanning movement with respect to a print medium and discharges ink to a surface of the print medium, a signal output unit which includes a reference scale in which optical density changes stepwise along a scanning movement direction of the discharge head and a reading unit that optically reads the reference scale and outputs a signal according to the optical density and in which the reference scale and the reading unit move relatively with each other along with the movement of the discharge head, and a stain detection unit that detects stain of the signal output unit based on a detection result of a strength level of the signal.

A printing apparatus including a discharge head that performs scanning movement with respect to a print medium and discharges ink to a surface of the print medium, a signal output unit which includes a reference scale in which optical density changes stepwise along a scanning movement direction of the discharge head and a reading unit that optically reads the reference scale and outputs a signal according to the optical density and in which the reference scale and the reading unit move relatively with each other along with the movement of the discharge head, and a stain detection unit that detects stain of the signal output unit based on a detection result of a strength level of the signal.

An image processing apparatus includes a hardware processor, an obtaining unit, a comparator, an adjuster and a notifying unit. The hardware processor obtains a read image from a reader that reads a print-through image formed on a back surface opposite an image forming surface of a recording medium. A target image is formed on the image forming surface with a color material, and the print-through image is formed on the back surface by the color material permeating through the recording medium. The obtaining unit obtains a comparison image in which the target image is at least recognizable. The comparator compares the read image with the comparison image. Depending on a result of the comparison by the comparator, the hardware processor causes at least one of (i) the adjuster to adjust a printing process parameter and (ii) the notifying unit to perform notification.

An image processing apparatus includes a hardware processor, an obtaining unit, a comparator, an adjuster and a notifying unit. The hardware processor obtains a read image from a reader that reads a print-through image formed on a back surface opposite an image forming surface of a recording medium. A target image is formed on the image forming surface with a color material, and the print-through image is formed on the back surface by the color material permeating through the recording medium. The obtaining unit obtains a comparison image in which the target image is at least recognizable. The comparator compares the read image with the comparison image. Depending on a result of the comparison by the comparator, the hardware processor causes at least one of (i) the adjuster to adjust a printing process parameter and (ii) the notifying unit to perform notification.

An ejection apparatus includes an ejection head having an ejection port, a droplet detection unit, an acquisition unit, a control unit, and a decision unit. The droplet detection unit detects that a droplet ejected from the ejection port has reached a predetermined position. The acquisition unit acquires information regarding a velocity of movement of the detected droplet. The control unit controls the ejection head to eject the droplet from the ejection port. The decision unit decides a number of consecutive ejections of a plurality of droplets from the ejection head based on the acquired information regarding the velocities of each of the plurality of droplets ejected consecutively and detected by the droplet detection unit. If the acquisition unit acquires the information regarding velocities of detected droplets, the control unit controls the ejection head to consecutively eject the droplets from the ejection head based on the decided number of consecutive ejections.

An element substrate of a liquid ejection head includes an ejection element for ejecting a liquid, a plurality of electrode pads for receiving power for causing the ejection element to eject the liquid, and a sensor for detecting that the liquid has invaded the vicinity of the plurality of electrode pads. The sensor has first wiring connected with one electrode pad of the plurality of electrode pads and second wiring connected with one electrode pad different from the electrode pad connected with the first wiring.