A printing apparatus is disclosed. The printing apparatus comprises a rotating housing comprising a wall with an inner side defining a chamber and an outer side. The wall has a bore communicating the inner side and the outer side, and the chamber is to receive a fluid container. The printing apparatus also comprises a fix frame holding the rotating housing. The printing apparatus further comprises an optical sensor comprising an emitter to issue a detecting optical signal through the bore and a receiver to receive a detected optical signal associated to the detecting optical signal. The detected signal is sent to a controller to determine whether the fluid container is present in the rotating housing.

A printing system is disclosed. The printing system includes at least one physical memory device to store halftone calibration logic and one or more processors coupled with the at least one physical memory device to execute the halftone calibration logic determine an uncalibrated deposition distribution for each of a plurality of pel forming elements, determine a calibrated deposition distribution for each of the plurality of pel forming elements and determine calibration values for each of the plurality of pel forming elements.

An apparatus for supplying chemical liquid may include a chemical liquid supply head, a receiving member, a removing member and a supplying member. The chemical liquid supply head may provide a chemical liquid onto a substrate. The receiving member may receive a recycle chemical liquid discharged from the chemical liquid supply head, and the removing member may remove impurities remaining in the recycle chemical liquid received in the receiving member. The supplying member may provide the recycle chemical liquid from which the impurities are removed to the chemical liquid supply head.

A fluid ejection and circulation apparatus may include a fluid ejection device, a filter to filter fluid supplied to the fluid ejection device and a pressure regulator. The pressure regulator may include a fluid chamber having a fluid port and a first port extending from the fluid chamber to the filter. The pressure regulator may further include a valve to open and close the fluid port and a compliant chamber within the fluid chamber. The compliant chamber is to undergo different inflation levels in response to fluid chamber pressure. The valve is to open and close the fluid port in response to changes in an inflation level of the compliant chamber. The fluid chamber comprises a second port cooperating with the first port to form a circulation path through the fluid chamber that is directed away from the filter.

A method of distinguishing between fluids may include providing a current to an electrode disposed within a fluidic passageway of a fluidic die, the current to be forced into a fluid within the fluidic die, sensing an impedance at the electrode, and determining a particle vehicle separation level of the fluid based on the sensed impedance between a first instance and a second instance.

A liquid discharge apparatus includes a recording head configured to discharge a liquid to form a pattern on a recording medium and a reading device configured to read the pattern. The apparatus further includes circuitry configured to form at least two first markers while moving the recording head relative to the recording medium in a head movement direction; form a second marker at one of positions of the at least two first markers, to form a pattern including a reference marker formed with one of the at least two first markers and a measurement marker in which the second marker is overlaid on another of the at least two first markers; and measure a distance between the reference marker and the measurement marker in the head movement direction based on information obtained by the reading device.

Density unevenness accompanying a variation in an ejection characteristic of each nozzle is reduced without worsening granularity of an image. To this end, an image processing apparatus generates first corrected data by correcting image data by using a first correction table common to the plurality of nozzles. Further, the image processing apparatus generates second corrected data by correcting the image data by using a second correction table for each of the plurality of nozzles. Furthermore, the image processing apparatus generates first quantized data by quantizing the first corrected data and generates second quantized data by quantizing the second corrected data. After that, the image processing apparatus generates N-valued print data based on the first quantized data and the second quantized data.

Disclosed is a method to mitigate deterioration of printing fluid in a tank of a printer. The method comprises: draining printing fluid from a tank of a printer, and stopping the draining before the tank is empty, wherein the printing fluid comprises solids suspended in imaging oil, filtering the printing fluid drained from the tank, to separate at least some of the solids from the imaging oil, passing the filtered imaging oil to a reservoir; and then passing imaging oil from the reservoir to the tank. Also disclosed is a printer and a system to perform the method.

An inkjet printer includes a maintenance solution supply mechanism. In response to switching of a three-way valve provided in an ink pipe, a maintenance solution is supplied from a maintenance tank to each head through a maintenance pipe. The maintenance tank is a common tank. This suppresses size increase of the printer compared to provision of an individual maintenance tank for each head. The maintenance pipe is connected to the ink pipe at a position downstream of an intermediary tank. This eliminates the need of replacement of ink in the intermediary tank by the maintenance solution during supply of the maintenance solution. This allows reduction in the consumptions of the ink and the maintenance solution.

An inkjet printer includes a maintenance solution supply mechanism. In response to switching of a three-way valve provided in an ink pipe, a maintenance solution is supplied from a maintenance tank to each head through a maintenance pipe. The maintenance tank is a common tank. This suppresses size increase of the printer compared to provision of an individual maintenance tank for each head. The maintenance pipe is connected to the ink pipe at a position downstream of an intermediary tank. This eliminates the need of replacement of ink in the intermediary tank by the maintenance solution during supply of the maintenance solution. This allows reduction in the consumptions of the ink and the maintenance solution.