A printing apparatus includes a printing head including a first nozzle configured to discharge a first ink and a second nozzle configured to discharge a second ink having a higher brightness than the first ink, and a control unit configured to control the printing head to print, on a printing medium, a test pattern for inspecting a state of ink discharge by the first nozzle and the second nozzle. The test pattern includes a first pattern element formed by a plurality of dots of the first ink and a second pattern element formed by a plurality of dots of the second ink. The control unit causes the printing head to print the test pattern where a number of the dots of the second ink forming the second pattern element is greater than a number of the dots of the first ink forming the first pattern element.

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.

A print head includes ejecting portions ejecting liquid by being supplied with a high voltage signal, a switch group switching between whether or not to supply the high voltage signal to the first ejecting portion group in accordance with a low voltage logic signal, a memory, a high voltage signal input terminal, and a low voltage logic signal input terminal, the print head having a first mode in which the print head executes reading processing of reading information stored in the memory and does not execute ejection control processing of controlling whether or not to supply the high voltage signal to the first ejecting portion group by switching the switch group in accordance with an input signal input from the low voltage logic signal input terminal and a second mode in which the print head does not execute the reading processing and executes the ejection control processing.

In an inkjet printing system, an actuator that is associated with a nozzle of a printing element is controlled in a normal operating mode, given a non-defective nozzle, to implement at least one standard refresh measure if the time period in which the actuator is not activated to output an ink droplet exceeds a preset limit value. After detection of a defective nozzle, the actuator is controlled in an error operating mode to implement at least one intensified refresh measure.

An image recording apparatus includes a recording head including a plurality of nozzles from which ink is ejected, a memory, and one or more hardware processors coupled to the recording head and the memory. The one or more hardware processors are configured to: determine, for each of the plurality of nozzles, whether a position of the corresponding nozzle is a position to eject ink; determine whether a successive ejection operation is necessary for a nozzle out of the plurality of nozzles, whose position is determined as the position to eject ink; and cause ink to be successively ejected at the position to eject ink at a predetermined successive ejection frequency from the nozzle that is determined to have the necessity of the successive ejection operation.

There is provided an image recording apparatus, including: a conveyer; a recording head; a carriage; a signal output circuit; and a controller. When recording is performed by a multi-pass recording mode, when the number of defective-discharge nozzles is less than a predefined value, when a discharge-defective nozzle, in which a dot recording ratio using a first mask data is equal to or more than a threshold value, is included in nozzles, and when a discharge-defective nozzle, in which a dot recording ratio using a second mask data is equal to or more than the threshold value, is not included in the nozzles, the controller sets the second mask data as a used mask data and performs recording without a suction purge. In other cases, the controller sets the first mask data as the used mask data and performs a purge process before recording as needed.

A method for assessing the condition and improving the printing quality of printing nozzles in printheads of an inkjet printing machine includes printing a nozzle test chart formed of a specific number of horizontal rows of equidistant vertical lines printed periodically underneath one another, with only every n.sup.th printing nozzle contributing to the test chart in every row of the test chart and n corresponding to a different number between one and the specific number of horizontal rows, recording and digitizing the test chart and analyzing the test chart regarding the condition of the contributing nozzles by using a computer. The nozzles printing horizontal lines between the horizontal rows complementing the equidistant vertical lines to form quadrangular objects used by the computer to analyze the condition of the contributing nozzles. Measures are taken to improve the printing quality of the nozzles depending on the condition of the contributing nozzles.

A print element substrate, comprising a plurality of heating elements, a plurality of detection elements, each configured to detect a temperature of a corresponding heating element, a first current generation unit, a second current generation unit, and a signal output unit, wherein one of the first and second current generation units supplies a current to a first detection element, the other supplies a current to a second detection element, and the signal output unit outputs a signal according to a potential difference between one terminal of the first detection element on a side where a potential variation occurs upon supply of the current and one terminal of the second detection element on a side where a potential variation occurs upon supply of the current.

Although a conventional method of inspecting an ink discharge state in which the temperature change of the heater is detected enables accurate and high-speed inspection, due to the situation in which the inspection was performed, appropriate post-processing depending on the situation cannot be executed based on a result of the inspection. Therefore, it is necessary to determine the ink discharge state in detail. A plurality of modes are provided in accordance with the purpose of performing an inspection of the ink discharge state, and a discharge inspection threshold is provided for each of these modes. By selectively executing or continuously executing these modes, it is possible to determine the ink discharge state in more detail.

There is provided print apparatus including: piezoelectric member; individual electrode; first and second common electrodes; voltage application circuit; detection circuit configured to detect a capacitance of a first capacitor configured by the piezoelectric member, the individual electrode, and the first common electrode and a second capacitor configured by the piezoelectric member, the individual electrode, and the second common electrode; first switching element; and control circuit. The control circuit is configured to execute; a first voltage application process to apply a first voltage to the second common electrode in order to discharge the ink; a detection process to detect the capacitance after electrically connecting the piezoelectric member and the detection circuit with the first switching element; and a second voltage application process to apply a second voltage to the second common electrode before the detection process, the second voltage being lower than the first voltage.