Abstract: A mode controller outputs a characteristic value according to a DC component of a developing current measured by an ammeter at a predetermined measurement timing. The measurement timing is defined as a timing at which a non-image forming region of a surface of a photosensitive drum is located opposite to a developing roller in the entirety of an axial direction and an electric field in a direction in which a toner moves from the photosensitive drum toward the developing roller by a potential difference between a surface potential of the photosensitive drum and the DC component of a developing bias is formed in a developing nip part. A determining section determines an execution timing for a charge amount acquisition operation according to the characteristic value output by the mode controller.

Abstract: An image forming apparatus includes a photosensitive drum, a developing section, a voltage applicator, a detector, a calculating section, and an evaluating section. The detector detects values of first and second currents. The first current flows between the photosensitive drum and the developing section during formation of an electrostatic latent image. The second current flows between the photosensitive drum and the developing section when the electrostatic latent image is not being formed. The calculating section calculates a toner charge-to-mass ratio. The evaluating section evaluates reliability of a calculation result of the toner charge-to-mass ratio by comparing the second current value to a reference value. The reference value is of a reference current flowing between the photosensitive drum and the developing section when the electrostatic latent image is not being formed, and indicates a current value detected after adjustment to at least one of the photosensitive drum and the developing section.

Abstract: An image forming apparatus includes a photosensitive drum, a developing section, a voltage applicator, a detector, a calculating section, and an evaluating section. The detector detects values of first and second currents. The first current flows between the photosensitive drum and the developing section during formation of an electrostatic latent image. The second current flows between the photosensitive drum and the developing section when the electrostatic latent image is not being formed. The calculating section calculates a toner charge-to-mass ratio. The evaluating section evaluates reliability of a calculation result of the toner charge-to-mass ratio by comparing the second current value to a reference value. The reference value is of a reference current flowing between the photosensitive drum and the developing section when the electrostatic latent image is not being formed, and indicates a current value detected after adjustment to at least one of the photosensitive drum and the developing section.

Abstract: A mode controller outputs a characteristic value according to a DC component of a developing current measured by an ammeter at a predetermined measurement timing. The measurement timing is defined as a timing at which a non-image forming region of a surface of a photosensitive drum is located opposite to a developing roller in the entirety of an axial direction and an electric field in a direction in which a toner moves from the photosensitive drum toward the developing roller by a potential difference between a surface potential of the photosensitive drum and the DC component of a developing bias is formed in a developing nip part. A determining section determines an execution timing for a charge amount acquisition operation according to the characteristic value output by the mode controller.

Abstract: A mode control section forms a plurality of reference toner images having different densities on a photosensitive drum, where the frequency of an alternating-current voltage of a development bias is varied with a potential difference between direct-current voltages of a development roller and the photosensitive drum maintained constant, generates a reference straight line indicating a relationship between a toner amount of each reference toner image obtained by converting the density of the measured reference toner image into weight, and a representative value of current values of a development current measured during formation of the reference toner image, and acquires the amount of electrostatic charge of toner using the reference straight line.

Abstract: A mode control section forms a plurality of reference toner images having different densities on a photosensitive drum, where the frequency of an alternating-current voltage of a development bias is varied with a potential difference between direct-current voltages of a development roller and the photosensitive drum maintained constant, generates a reference straight line indicating a relationship between a toner amount of each reference toner image obtained by converting the density of the measured reference toner image into weight, and a representative value of current values of a development current measured during formation of the reference toner image, and acquires the amount of electrostatic charge of toner using the reference straight line.

Abstract: An image forming apparatus includes a photoconductor, a charging member, a voltage applier, a storage unit, a current detector, a characteristic deriver and a voltage setter. The storage unit stores in advance relationship information representing a relationship between an electrical characteristic of discharge products adhering to the surface and a proper inter-peak voltage value capable of properly charging the surface. The current detector detects a current value of a current flowing from the charging member to the photoconductor. The characteristic deriver derives the electrical characteristic of the discharge products adhering to the surface on the basis of an oscillating voltage applied to the charging member by the voltage applier and the current value. The voltage setter sets the proper inter-peak voltage value corresponding to the electrical characteristic derived by the characteristic deriver in the relationship information as the inter-peak voltage value of the alternating-current voltage.

Abstract: An image forming apparatus includes a photoconductor, a charging member, a voltage applier, a rubbing member, a process executor, a current detector, a characteristic deriver and a process controller. The rubbing member is arranged in contact with a surface of the photoconductor to rub the surface. The process executor executes a refresh process of causing the rubbing member to rub the surface for a predetermined time by supplying toner to the rubbing member. The current detector detects a current value of a current flowing from the charging member to the photoconductor. The characteristic deriver derives an electrical characteristic of discharge products adhering to the surface on the basis of an oscillating voltage applied to the charging member by the voltage applier and the current value. The process controller determines whether or not to re-execute the refresh process according to the electrical characteristic when the refresh process is finished.

Abstract: An image forming apparatus includes a photoconductor, a charging member, a voltage applier, a storage unit, a current detector, a characteristic deriver and a voltage setter. The storage unit stores in advance relationship information representing a relationship between an electrical characteristic of discharge products adhering to the surface and a proper inter-peak voltage value capable of properly charging the surface. The current detector detects a current value of a current flowing from the charging member to the photoconductor. The characteristic deriver derives the electrical characteristic of the discharge products adhering to the surface on the basis of an oscillating voltage applied to the charging member by the voltage applier and the current value. The voltage setter sets the proper inter-peak voltage value corresponding to the electrical characteristic derived by the characteristic deriver in the relationship information as the inter-peak voltage value of the alternating-current voltage.

Abstract: An image forming apparatus includes a photoconductor, a charging member, a voltage applier, a rubbing member, a process executor, a current detector, a characteristic deriver and a process controller. The rubbing member is arranged in contact with a surface of the photoconductor to rub the surface. The process executor executes a refresh process of causing the rubbing member to rub the surface for a predetermined time by supplying toner to the rubbing member. The current detector detects a current value of a current flowing from the charging member to the photoconductor. The characteristic deriver derives an electrical characteristic of discharge products adhering to the surface on the basis of an oscillating voltage applied to the charging member by the voltage applier and the current value. The process controller determines whether or not to re-execute the refresh process according to the electrical characteristic when the refresh process is finished.

Abstract: An image forming apparatus includes an image carrier, a developing device, a detecting device and a vibration imparting device. The image carrier rotates around an axis. The developing device includes a developing member rotating around an axis at a position facing the image carrier and supplying a toner to the image carrier. The detecting device detects a number of the toner scattered from an inside to an outside of the developing device. The vibration imparting device imparts vibration to the toner accumulated near the developing member when the number of the toner detected by the detecting device satisfies a predetermined condition.

Abstract: An image forming apparatus includes an image carrier, a developing device, a detecting device and a vibration imparting device. The image carrier rotates around an axis. The developing device includes a developing member rotating around an axis at a position facing the image carrier and supplying a toner to the image carrier. The detecting device detects a number of the toner scattered from an inside to an outside of the developing device. The vibration imparting device imparts vibration to the toner accumulated near the developing member when the number of the toner detected by the detecting device satisfies a predetermined condition.

Abstract: A toner replenishment device includes a toner receiving port, a toner feed unit feeding toner from the toner receiving port into the device, a toner detector detecting that the device has been filled with a specified amount of the toner, an agitating member having an agitating blade and rotating so as to agitate the toner in the device, a position detector detecting a rotational position of the agitating member and generating a signal indicative thereof, and a recognition unit recognizing the rotational position based on the signal output from the position detector. The toner feed unit feeds the toner into the device when an end edge of the agitating blade is within a specified range, in which a flow path of the toner from the toner receiving port to the toner detector is not blocked by the agitating blade, based on the recognition performed by the recognition unit.

Abstract: A toner replenishment device includes a toner receiving port, a toner feed unit feeding toner from the toner receiving port into the device, a toner detector detecting that the device has been filled with a specified amount of the toner, an agitating member having an agitating blade and rotating so as to agitate the toner in the device, a position detector detecting a rotational position of the agitating member and generating a signal indicative thereof, and a recognition unit recognizing the rotational position based on the signal output from the position detector. The toner feed unit feeds the toner into the device when an end edge of the agitating blade is within a specified range, in which a flow path of the toner from the toner receiving port to the toner detector is not blocked by the agitating blade, based on the recognition performed by the recognition unit.

Abstract: The present invention teaches and claims an image forming apparatus using a time measuring apparatus to accurately measure the time in which the image forming apparatus stays in one or more modes. The image forming apparatus comprises a first CPU which outputs a pulse signal to a receiving second CPU. The second CPU calculates, by using the received pulse signal, a timer error of a second clock signal. The time measuring apparatus measures time in one or more modes based on the second clock signal and then corrects the measured time using the calculated timer error.

Abstract: A toner replenishment device includes a toner receiving port, a toner feed unit feeding toner from the toner receiving port into the device, a toner detector detecting that the device has been filled with a specified amount of the toner, an agitating member having an agitating blade and rotating so as to agitate the toner in the device, a position detector detecting a rotational position of the agitating member and generating a signal indicative thereof, and a recognition unit recognizing the rotational position based on the signal output from the position detector. The toner feed unit feeds the toner into the device when an end edge of the agitating blade is within a specified range, in which a flow path of the toner from the toner receiving port to the toner detector is not blocked by the agitating blade, based on the recognition performed by the recognition unit.

Abstract: A toner replenishment device includes a toner receiving port, a toner feed unit feeding toner from the toner receiving port into the device, a toner detector detecting that the device has been filled with a specified amount of the toner, an agitating member having an agitating blade and rotating so as to agitate the toner in the device, a position detector detecting a rotational position of the agitating member and generating a signal indicative thereof, and a recognition unit recognizing the rotational position based on the signal output from the position detector. The toner feed unit feeds the toner into the device when an end edge of the agitating blade is within a specified range, in which a flow path of the toner from the toner receiving port to the toner detector is not blocked by the agitating blade, based on the recognition performed by the recognition unit.

Abstract: The present invention teaches and claims an image forming apparatus using a time measuring apparatus to accurately measure the time in which the image forming apparatus stays in one or more modes. The image forming apparatus comprises a first CPU which outputs a pulse signal to a receiving second CPU. The second CPU calculates, by using the received pulse signal, a timer error of a second clock signal. The time measuring apparatus measures time in one or more modes based on the second clock signal and then corrects the measured time using the calculated timer error.