In one example in accordance with the present disclosure, a fluidic die is described. The fluidic die includes an array of firing subassemblies grouped into zones. Each firing subassembly includes 1) a firing chamber, 2) a fluid actuator disposed, and 3) a sensor plate. The fluidic die also includes a measurement device per zone to determine a state of a selected sensor plate. The fluidic die includes a selector per firing subassembly to couple the selected sensor plate to the measurement device. The fluidic die also includes a transmission path between each selector and its corresponding sensor plate. A first transmission path for a particular sensor plate has physical properties such that a parasitic capacitance along the first transmission path corresponds to a parasitic capacitance for a second transmission path of a second sensor plate in the zone, regardless of a difference in transmission path length.

In a liquid ejection apparatus, a controller of the liquid ejection apparatus is configured to, in response to receiving a recording instruction to instruct the liquid ejection apparatus to perform image recording on a recording medium, perform ejection inspection to determine whether liquid is ejected from each nozzle of a liquid ejection head toward an electrode based on a signal outputted from a signal output circuit. For the ejection inspection, the controller is configured to control a voltage applying circuit to apply an inspection voltage between the electrode and the liquid ejection head. In response to detecting that a leakage current greater than a predetermined value flows between the electrode and the liquid ejection head, the controller is configured to cancel the ejection inspection and control a voltage applying circuit to apply a reverse voltage opposite in polarity to the inspection voltage between the electrode and the liquid ejection head.

A fluid ejection head and a method of detecting the presence of fluid in an ejection chamber. The ejection head includes a semiconductor substrate having an elongate fluid supply via etched therethrough. An array of fluid ejectors is disposed adjacent to the fluid supply via, wherein the elongate fluid supply via provides fluid to the array of fluid ejectors for ejection of fluid from the ejection head. Fluid sense cells for the array of fluid ejectors are disposed at each end of the fluid supply via, wherein each of the fluid sense cells has a fluid ejector, an electrode disposed in a fluid chamber for the fluid ejector, and an electrode disposed in a fluid channel associated with a fluid chamber. A fluid detection circuit is provided in electrical communication with each of the fluid sense cells for detecting the presence or absence of fluid in the fluid chamber.

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.

An image forming apparatus includes a print head, a main control unit, a head control unit, and a head unit power supply to generate a voltage to be supplied to the head control unit. The main control unit checks whether the main control unit is normally started up. The head control unit includes an operation checker to check whether the head control unit normally operates if the main control unit is normally started up and the head control unit is supplied with a check voltage, a head power supply generator to generate a voltage to be supplied to the print head if the head control unit normally operates, and a status detector to detect a status of the print head based on the voltage supplied to the print head, and control the voltage to be supplied to the head control unit depending on the status detected by the status detector.

A memory circuit for a print component including plurality of I/O pads, including a first analog pad and a second analog pad, to connect to a plurality of signal paths which communicate operating signals to the print component, including an analog signal path connected to the first analog pad and the second analog pad, the first analog pad electrically isolated from the second analog pad to interrupt the analog signal path to the print component. The memory circuit further includes a memory component to store memory values associated with the print component, and a control circuit to, in response to a sequence of operating signals received by the I/O pads representing a memory read, provide an analog signal to the analog pad to provide an analog electrical value at the analog pad representing stored memory values selected by the memory read.

In one example in accordance with the present disclosure, a fluidic die is described. The fluidic die includes an array of firing subassemblies grouped into zones. Each firing subassembly includes 1) a firing chamber, 2) a fluid actuator, and 3) a sensor plate. The fluidic die also includes a measurement device per zone to measure a voltage indicative of an impedance within a selected firing chamber. The fluidic die includes a selector per firing subassembly to couple a selected sensor plate to the measurement device. A selector is adjacent a respective firing subassembly and a distance between the selector and the measurement device is different as compared to other selectors.

Example implementations relate to current leakage testing of a fluid ejection die. For example, a fluid ejection die may include plurality of nozzles, each nozzle among the plurality of nozzles including a nozzle sensor and a fluid ejector. The plurality of nozzle sensors may comprise a first subset and a second subset, each nozzle sensor among the plurality of nozzle sensors of the first subset may be electrically coupled to a first control line by a respective switch among a first group of switches, and each nozzle sensor among the plurality of nozzle sensors of the second subset may be electrically coupled to a second control line by a respective switch among a second group of switches. The fluid ejection die may include a control circuit to perform a current leakage test of the plurality of nozzles using the first control line and the second control line.

An integrated circuit to drive a plurality of fluid actuation devices includes a contact pad and a programmable pulldown device. The programmable pulldown device is electrically coupled to the contact pad. The programmable pulldown device is settable to any one of a plurality of resistances.

A memory circuit for a print component including a plurality of I/O pads, including an analog pad, to connect to a plurality of signal paths which communicate operating signals to the print component. The memory circuit includes a controllable selector connected in line with one of the signal paths via the I/O pads, the selector controllable to disconnect the corresponding signal path to the print component, and a memory component to store memory values associated with the print component. A control circuit, in response to a sequence of operating signals received by the I/O pads representing a memory read, to operate the controllable selector to disconnect the signal path to the print component to block the memory read of the print component, and provide an analog signal to the analog pad to provide an analog electrical value at the analog pad representing stored memory values selected by the memory read.