Abstract: A developing device includes a developing case, a filter, and a filter holder. The developing case stores developer inside to develop a latent image formed on a surface of an image bearer and has an opening portion that communicates between an inside and an outside of the developing device. The filter has a lower weight density per unit volume at a first side of the filter facing the inside of the developing device than a weight density per unit volume at a second side of the filter facing the outside of the developing device. The filter holder is detachably attached to the opening portion of the developing case with the filter held by the filter holder.

Abstract: A powder-amount detection device includes a first electrode, a second electrode, a third electrode and a voltage detector with the second electrode adjacent to the first electrode on the powder container and have a smaller surface area than a surface area of the first electrode. The third electrode is on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode. The voltage detector detects voltages of the first electrode and the second electrode by detecting charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, and detects the amount of powder in the powder container based on the voltages of the first electrode and the second electrode.

Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.

Abstract: An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.

Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.

Abstract: A powder-amount detection device includes a first electrode disposed on one side of a powder container to be replaceably installed to an image forming apparatus; a second electrode disposed adjacent to the first electrode and having a smaller surface area than the first electrode, an influence of an amount of powder in the powder container to a capacitance of the second electrode being as small as negligible; a third electrode disposed on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode; and a voltage detector configured to detect charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, to detect the amount of powder in the powder container.

Abstract: An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.