Abstract: A sheet identification device includes a light irradiation portion. When forming an identification image, the light irradiation portion projects first pattern light (P11) and second pattern light (P12) having different dependences on a fiber direction of a surface of a sheet on an identification region (R1). The identification image is an image of the identification region (R1) of the surface of the sheet on which image formation or image reading is performed, which is used for identifying the fiber direction of the surface of the sheet.

Abstract: An image forming apparatus includes a developing member, a first detection processing portion, and an acquisition processing portion. The developing member conveys developer to a facing portion between the developing member and the image-carrying member. The first detection processing portion detects a first development current for each of a plurality of specific voltages with different DC voltage values applied to the developing member, the first development current flowing, in response to application of the specific voltages, through the facing portion including the developer and a specific exposed area, formed by the light emitting portion, on the image-carrying member. The acquisition processing portion acquires a potential value of the specific exposed area based on the DC voltage values of the specific voltages and current values of the first development current, detected by the first detection processing portion, corresponding to the respective specific voltages.

Abstract: An image forming apparatus includes first, second, and third acquisition processing portions. The first acquisition processing portion acquires the potential value of a charged area, charged by the charging member, on the image-carrying member. The second acquisition processing portion acquires a state value regarding the state of a surface layer of the image-carrying member based on the potential value of the charged area acquired by the first acquisition processing portion and the current value of a charging current flowing through the charging member during formation of the charged area. The third acquisition processing portion acquires the electrical resistance value of the transfer member based on the state value acquired by the second acquisition processing portion, the voltage value of a transfer voltage applied to the transfer member, and the current value of a transfer current flowing through the charged area in response to application of the transfer voltage.

Abstract: An image forming apparatus includes an image-carrying member, a first acquisition processing portion, and a second acquisition processing portion. An electrostatic latent image is formed on the image-carrying member. The first acquisition processing portion acquires the potential value of the image-carrying member. The second acquisition processing portion acquires the temperature value of the image-carrying member based on the potential value of the image-carrying member acquired by the first acquisition processing portion.

Abstract: Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. The developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. The density detecting device detects the density of the toner image. The current detecting unit detects a DC component of a developing current that flows when a developing voltage is applied to the developer carrier. The control unit, in a state in which the image carrier is rotated at two or more different linear speeds during non-image formation, forms the same reference image on the image carrier by the developing device, and estimates the toner charge amount based on the developing current when the reference image is formed and the density of the reference image.

Abstract: Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. A developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. A developing voltage power supply applies a developing voltage obtained by superimposing an AC voltage on a DC voltage on the developer carrier. A control unit estimates a toner charge amount based on a toner current calculated by subtracting a carrier current from a developing current detected by a current detecting unit when a reference image is formed during non-image formation, and a toner developing amount calculated from the density of a reference image detected by a density detecting device.

Abstract: An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a two-component developer. The control portion can perform a transfer memory prediction mode that includes a step of estimating, when a first reference image is formed, the level of occurrence of transfer memory based on the direct-current component of a development current flowing through the developer carrying member and a step of measuring, when the measured direct-current component of the development current is larger than a predetermined value, the amount of charge of the toner within the developing device and estimating the cause of occurrence of the transfer memory based on the measured amount of charge of the toner.

Abstract: Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. A developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. A developing voltage power supply applies a developing voltage obtained by superimposing an AC voltage on a DC voltage on the developer carrier. A control unit estimates a toner charge amount based on a toner current calculated by subtracting a carrier current from a developing current detected by a current detecting unit when a reference image is formed during non-image formation, and a toner developing amount calculated from the density of a reference image detected by a density detecting device.

Abstract: Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. The developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. The density detecting device detects the density of the toner image. The current detecting unit detects a DC component of a developing current that flows when a developing voltage is applied to the developer carrier. The control unit, in a state in which the image carrier is rotated at two or more different linear speeds during non-image formation, forms the same reference image on the image carrier by the developing device, and estimates the toner charge amount based on the developing current when the reference image is formed and the density of the reference image.

Abstract: An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm2] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

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 an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm2] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

Abstract: An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a two-component developer. The control portion can perform a transfer memory prediction mode that includes a step of estimating, when a first reference image is formed, the level of occurrence of transfer memory based on the direct-current component of a development current flowing through the developer carrying member and a step of measuring, when the measured direct-current component of the development current is larger than a predetermined value, the amount of charge of the toner within the developing device and estimating the cause of occurrence of the transfer memory based on the measured amount of charge of the toner.

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: Provided is an inexpensive image forming apparatus capable of monitoring the generating state of various powders. The image forming apparatus includes a minute-particle-measuring device, a toner-particles-detecting air duct, a paper-dust-detecting air duct, and blower fans. The minute-particle-measuring device detects the concentration of minute particles in air. The toner-particle-detecting air duct is an air duct leading from the image forming unit to the minute-particle-measuring device. The paper-dust-detecting air duct is an air duct leading from the paper-conveying path to the minute-particle-measuring device. The blower fans are respectively provided in the toner-particle-detecting air duct and the paper-dust-detecting air duct, and generate airflow that flows toward the minute-particle-measuring device side. The blower fans in the toner-particle-detecting air duct and in the paper-dust-detecting air duct are switched.

Abstract: Provided is an inexpensive image forming apparatus capable of monitoring the generating state of various powders. The image forming apparatus includes a minute-particle-measuring device, a toner-particles-detecting air duct, a paper dust-detecting air duct, and blower fans. The minute-particle-measuring device detects the concentration of minute particles in air. The toner-particle-detecting air duct is an air duct leading from the image forming unit to the minute-particle-measuring device. The paper-dust-detecting air duct is an air duct leading from the paper-conveying path to the minute-particle-measuring device. The blower fans are respectively provided in the toner-particle-detecting air duct and the paper-dust-detecting air duct, and generate airflow that flows toward the minute-particle-measuring device side. The blower fans in the toner-particle-detecting air duct and in the paper-dust-detecting air duct are switched.

Abstract: An image forming apparatus includes a controller, a transmitter, a receiver, and an input receiving device. Upon the controller detecting a replacement unit that needs to be replaced, the transmitter transmits, to an external device, unit information indicating the replacement unit. The receiver receives, from the external device via a network, replacement procedure information of the replacement unit detected by the controller and identification information of a worker who is to replace the replacement unit. Upon the input receiving device receiving input of identification information that matches the identification information of the worker received by the receiver, the controller shifts an operation state of the image forming apparatus from a normal power supply mode to a unit replacement mode in which power is supplied only to predetermined components of the image forming apparatus other than the replacement unit.

Abstract: An image forming apparatus includes a controller, a transmitter, a receiver, and an input receiving device. Upon the controller detecting a replacement unit that needs to be replaced, the transmitter transmits, to an external device, unit information indicating the replacement unit. The receiver receives, from the external device via a network, replacement procedure information of the replacement unit detected by the controller and identification information of a worker who is to replace the replacement unit. Upon the input receiving device receiving input of identification information that matches the identification information of the worker received by the receiver, the controller shifts an operation state of the image forming apparatus from a normal power supply mode to a unit replacement mode in which power is supplied only to predetermined components of the image forming apparatus other than the replacement unit.