An operation method of an image forming apparatus including determining a state of a toner refill operation of injecting toner from a toner reload kit (TRK) to a cartridge in the image forming apparatus; when determined the injecting of the toner into the cartridge is completed, controlling the TRK to store information indicating a toner refill completion in a memory of the TRK; and updating information of an amount of remaining toner of the cartridge, based on an amount of the toner injected into the cartridge from the TRK.

An inkjet recording apparatus includes a first ink tank that contains ink, a second ink tank that contains ink supplied from the first ink tank, a communication unit, having conductivity, communicates between the first ink tank and the second ink tank, an opening provided at one end of the communication unit connected to the second ink tank and opening to the second ink tank, an electrode portion provided in the second ink tank, of which a lower end position is located at or above a lower end position of the one end of the communication unit and at or below a highest position of the opening, and a detecting unit that detects an ink amount in the second ink tank in accordance with electrical properties between the electrode portion and the communication unit.

A logic circuitry package for a replaceable print apparatus component comprises an interface to communicate with a print apparatus logic circuit, and at least one logic circuit. The logic circuit may be configured to identify, from a command stream received from the print apparatus, parameters including a class parameter, and/or identify, from the command stream, a read request, and output, via the interface, a count value in response to a read request, the count value based on identified received parameters.

A liquid level sensor package for a replaceable print liquid reservoir, the package including a number of heater circuits, each heater circuit including a heater element to dissipate heat and a number of control devices, each control device individually controllable to be electrically connected to the heater element, the heater element to dissipate a different amount of heat when electrically connected to different ones of the control devices.

A sensor circuitry package for a replaceable print apparatus component including a plurality of sensing zones, each sensing zone including a number of sensing devices, each sensing device having a respective sensing function, and an array of memory elements, each memory element corresponding to a respective one of the sensing zones. During a sensing operation, the array of memory elements to serially load a segment of select bits, each select bit having one of a select value and a non-select value, a memory element having a select value to select a number of sensing devices of the respective sensing zone to be enabled to perform its respective sensing function.

A liquid level sensor package for a replaceable print liquid reservoir, the package including a substrate, a surface layer to contact a print liquid in the print liquid reservoir, and a layer stack including a number of metal layers disposed between the substrate and the surface layer. An array of heater elements disposed in one of the metal layers of the layer stack, and an array of thermal sensors disposed in a different one of the metal layers of the layer stack, each thermal sensor corresponding to a different heater element of the array of heater elements, and each thermal sensor to provide indication of a presence or absence of print liquid based on a sensed temperature after being heated by the corresponding heater element.

A liquid level sensor package for a replaceable print liquid reservoir, the package including a number of heater circuits, each heater circuit including a heater element to dissipate heat and a number of control devices, each control device individually controllable to be electrically connected to the heater element, the heater element to dissipate a different amount of heat when electrically connected to different ones of the control devices.

In an example, a method comprises fabricating a first validation device for association with a first replaceable print apparatus component. The device may be to form part of circuitry arranged on the first replaceable print apparatus component, and may provide an associated electrically detectable characteristic which varies with the position of at least part of the first validation device. The electrically detectable characteristic may be measured and data indicative of the characteristic may be stored in a first memory. The first replaceable print apparatus component comprising the first device and the first memory may be assembled.

An image recording apparatus includes a liquid chamber that stores liquid, a first electrode pin and a second electrode pin to be inserted into the liquid chamber, applying unit for applying voltage across the first electrode pin and the second electrode pin, with the first electrode pin as an anode side and the second electrode pin as a cathode side, and detecting unit for detecting electric current flowing, and detection operation of detecting amount of liquid in the liquid chamber by the detecting unit detecting the electric current when the applying unit applies voltage. Prior to the detection operation, an oxidization aging operation is performed, in which the applying unit applies voltage across the first electrode pin and the second electrode pin. An amount of an oxide layer formed on at least a portion of the first electrode pin exposed inside the liquid chamber is greater than the second.

Provided is an inkjet printing apparatus comprising: a print head that ejects ink; a tank that contains ink to be supplied to the print head; a floating body that floats on the liquid surface of the ink inside the tank; and an electrode pin that detects the level of the liquid surface inside the tank. The floating body includes an opening portion in which to insert the electrode pin, and a perimeter of the opening portion protrudes from a top surface side of the floating body.