A fluidic die includes a plurality of fluid chambers, each fluid chamber including an electrode exposed to an interior of the fluid chamber and having a corresponding fluid actuator operating a high voltage separated from the fluid chamber and electrode by an insulating material, and monitoring circuitry, operating at a low voltage, to monitor a condition of each fluid chamber. For each fluid chamber the monitoring circuitry includes a sense node and a conductor connecting the electrode to the sense node, the conductor having a geometry to form at least one region of higher current density relative to remaining portions of the conductor, the at least one region of higher current density to fail and create an open to protect the low-voltage monitoring circuitry in response to a fault current caused by a short circuit of the high voltage fluid actuator to the electrode.

A fluidic die may include at least one fluidic passageway, at least one electrode disposed within the at least one fluidic passageway, and control circuitry to activate the electrode within the fluidic die. An impedance sensed at the electrode corresponds to a particle concentration within the fluid. The control circuitry activates the electrode during a separate pulse group assigned to the activation of the electrode among at least one other pulse group assigned to an activation of at least one fluid actuator within a column group.

In one example in accordance with the present disclosure, a fluidic die is described is described. The fluidic die includes an array of fluid actuators grouped into zones. Each zone includes a number of fluid actuators and at least one fault detection device. The fault detection device includes a comparator to compare at least one of a representation of a supply voltage and a return voltage supplied to the zone against a voltage threshold. The fault detection device also includes a fault capture device to store an output of the comparator.

A liquid ejection head unit includes an ejection unit that ejects a liquid, a first wire configured to supply a fixed potential used for driving the ejection unit, a second wire configured to transmit a pulse signal that defines an ejection timing of the liquid in the ejection unit, a first counter whose count value changes based on a potential change in the first wire, a second counter whose count value changes based on a potential change in the second wire, and an ejection restriction unit that restricts an ejection operation of the liquid in the ejection unit according to a count value of the first counter and a count value of the second counter.

A print head drive circuit drives a print head including an ejecting portion ejecting a liquid in response to a drive signal propagating through a drive signal line and a storage portion storing ejecting portion-related information changing in accordance with use of the ejecting portion, in which processing of reading the ejecting portion-related information changing in accordance with the use from the storage portion is performed before the drive signal for ejecting the liquid from the ejecting portion is supplied to the print head.

A liquid discharge apparatus includes a plurality of anti-cavitation layers formed to cover heat generating elements at positions where the anti-cavitation layers contact the liquid, a monitoring unit that detects a current flowing through the anti-cavitation layers, and a plurality of switching units that switch whether to apply, to the heat generating elements, a voltage for driving the heat generating elements. If the monitoring unit detects that a current greater than a predetermined value has flowed through one of the anti-cavitation layers while the voltage is applied to the heat generating elements, a control unit sequentially switches the plurality of switching units, and specifies the heat generating element corresponding to the anti-cavitation layer through which the current has flowed, among the heat generating elements.

In one example in accordance with the present disclosure, a fluidic die is described. The fluidic die includes an array of fluid actuators grouped into primitives. Each actuator is disposed in a fluid chamber. The fluidic die also includes an array of fluid sensors. Each fluid sensor is disposed within a fluid chamber and determines a characteristic within the fluid chamber. A data parser of the fluidic die extracts from an incoming signal, firing instructions and measurement instructions for the fluidic die. The measurement instructions indicate at least one of a peak measurement during a nucleation event and a reference measurement during a non-nucleation event. A firing controller generates firing signals based on the firing instructions and a measurement controller activates, during a measurement interval of a printing cycle for the primitive, a measurement for a selected actuator based on the measurement instructions.

A fluidic die including fluid chambers, each including an electrode exposed to an interior of the fluid chamber and each having a corresponding fluid actuator operating at a first voltage level. Monitoring circuitry, operating at a second voltage level lower than the first voltage level, includes a select transistor and a pulldown transistor for each fluid chamber to selectively couple to the electrode, at least the select transistor being a high voltage tolerant transistor to operate at the second voltage in a normal operating condition and having a breakdown voltage level greater than the first voltage level to prevent a fault current from flowing into the select transistor from the electrode in a fault condition if the fluid actuator short-circuits to the electrode.

A fluidic die includes a high-side switch to selectively couple a power node to a power source, a pulldown switch to selectively couple the power node to a first reference voltage, a group of fluid actuators, each fluid actuator connected to the power node and each having a corresponding low-side switch to selectively couple the fluid actuator to a second reference voltage, and a group of fluid chambers, each including an electrode exposed to an interior of the fluid chamber, and each corresponding to a different one of the fluid actuators. Monitoring circuitry, during a monitoring operation, with the high-side switch and each low-side switch open, to connect to the electrode of a selected one of the fluid chambers, and to open the pulldown switch so that the fluid actuators are floating.

A fluid ejection die includes a plurality of nozzles to eject fluid drops and a plurality of strain gauge sensors to sense strain. Each strain gauge sensor corresponds to a nozzle and passes the sensed strain to a controller to determine the health of the nozzle based on the sensed strain.