A powder amount detector includes a vibration plate secured to a powder container to contain powder and positioned at a predetermined position in a stationary state, a shaft to rotate inside the powder container, a contact member attached to the shaft, a vibration detector to detect vibration of the vibration plate, and a detection result processor to determine an amount of the powder in the powder container according to a detection result generated by the vibration detector. The contact member is to flip the vibration plate to cause the vibration plate to repeat elastic deformation and reversion to vibrate. The contact member is to exit an area opposed to the vibration plate after the contact member flips the vibration plate by the time the vibration plate returns to the predetermined position.

A fluid detection apparatus to detect quantity of a fluid having flowability and stored in a casing includes an oscillator disposed outside the casing to output a frequency of an oscillation signal corresponding to a magnetic flux passing through a space near the oscillator, a vibrator made of material effecting the magnetic flux and disposed inside the casing, a vibration trigger disposed inside the casing to vibrate the vibrator, and circuitry to acquire frequency-related information related to the frequency of the oscillation signal output from the oscillator, detect the vibration of the vibrator based on a change of the frequency-related information, determine whether the vibration of the vibrator converges during a convergence-checking time period defined after the vibrator is vibrated by the vibration trigger, and detect the quantity of the fluid in the casing based on a convergence determination result of the vibration of the vibrator.

A development device includes a developer accommodating part that accommodates a developer, a developer detection member that is rotatably supported inside the developer accommodating part and is for detecting an amount of the developer accommodated inside the developer accommodating part, a rotational drive member that rotates the developer detection member around an rotational axis, and a conductive contact member that is formed of a conducive material. Wherein, defining a rotary track through which the developer detection member passes while rotating, a free edge of the contact member is arranged within the rotary track such that the contact member comes in contact with the developer detection member once while the developer detection member makes one rotation, the free edge being distal from where the contact member is fixed.

An image forming apparatus includes a developer conveyance device to transport developer, using a positive-displacement pump to alternately generate positive pressure and negative pressure by changing a volume of an internal space thereof, a destination developer container to which the developer conveyance device transports developer, a sensor provided to the destination developer container, to detect developer in the destination developer container, and a controller to control the positive-displacement pump according to a detection result generated by the sensor. The controller disabled detection of developer by the sensor in a non-detection period that starts from a stop of the positive-displacement pump.

A device includes an acceleration sensor, a charge variation sensor and processing circuitry. The acceleration sensor, in operation, generates an acceleration signal indicative of vibrations associated with a cartridge of a laser printer. The charge variation sensor, in operation, generates a charge-variation signal indicative of a variation of electrostatic charge associated with the cartridge of the laser printer. The processing circuitry is coupled to the acceleration sensor and to the charge variation sensor. The processing circuitry, in operation, generates feature parameters based on the acceleration signal and the charge-variation signal, and generates a level signal indicative of a level of toner in the cartridge based on the generated feature parameters. The generated feature parameters include a peak-to-peak distance of the acceleration signal and a maximum of the charge variation signal.

An image forming apparatus includes a toner container housing, an image forming device, a tuning fork, a vibration generator, a communication circuit, and a terminal. The toner container housing houses a toner bottle storing toner. The toner bottle includes an electrode on a surface of the toner bottle. The image forming device receives the toner in the toner bottle to form a toner image. The vibration generator vibrates the tuning fork. The communication circuit is electrically connected to the tuning fork. The terminal is coupled to the tuning fork and is contactable with the electrode to electrically connect the communication circuit and the electrode of the toner bottle in the toner container housing via the tuning fork. The vibration generator vibrates the tuning fork to vibrate the terminal contacting the electrode.