Abstract: An image forming apparatus includes a developing current detecting portion, a control portion, and a deviation detecting portion. The developing current detecting portion detects a developing current that flows between a developing device and a photoconductor drum during development of an electrostatic latent image. The control portion causes the exposure device to form electrostatic latent images of at least two patch images at different positions from each other and at different timings from each other in a main scanning direction. The deviation detecting portion detects deviation of one of the exposure device and the photoconductor drum with respect to the other based on a detection timing at which the developing current is detected during development of the electrostatic latent images of the at least two patch images.

Abstract: Provided is an image forming apparatus in which, while image formation is prevented from being performed, scattered toner that has dropped from a filter and adhered to an outer peripheral surface of a developer carrying member is recovered by a cleaning unit through intermediation of an image bearing member. An absolute value of a perpendicular-magnetic-force gradient of a fixed magnet of the developer carrying member is 4.0 mT/° or less at a position where the fixed magnet faces a central portion of the filter in a rotation direction of a developing sleeve.

Abstract: Provided is an image forming apparatus in which, while image formation is prevented from being performed, scattered toner that has dropped from a filter and adhered to an outer peripheral surface of a developer carrying member is recovered. A fixed magnet of the developer carrying member has a first pole that is arranged to face the filter, and a second pole and a third pole on a downstream side relative to the first pole. The first pole and the second pole have polarities opposite to each other, and the second pole and the third pole have a same polarity. A length of a gap between the developing container and an area where the developing sleeve faces the second pole among areas of the developing sleeve is smaller than a length between the developing sleeve and the filter.

Abstract: Provided is an image forming apparatus that is capable of carrying out a scattered-toner recovery mode in which, while image formation is prevented from being performed, scattered toner that has dropped from a filter and adhered to an outer peripheral surface of a developer carrying member is recovered by a cleaning unit through intermediation of an image bearing member. A fixed magnet of the developer carrying member has a first pole that faces the image bearing member, a second pole that faces the filter, and an intermediate pole between the first pole and the second pole.

Abstract: An image forming apparatus includes a development device, and a control unit that controls the development device. The development device includes a toner collection mechanism having a duct, a filter, and an exhaust fan. The duct is connected to a conveyance chamber of the development container and allows air in the conveyance chamber to flow through. The filter is disposed at a connecting part between the duct and the conveyance chamber, and collects toner flowing into the duct from the conveyance chamber. The exhaust fan makes the air in the conveyance chamber flow to the outside via the duct. The control unit changes rotational frequency or operation frequency of the exhaust fan based on current detected by a current detection unit at non-image forming time.

Abstract: An image forming apparatus includes an image carrier, a cleaning unit, a development device, and a control unit. The development device includes a toner collection mechanism having a developer carrier and a filter. The control unit is capable of executing a scattered toner recovery mode at non-image forming time, in which the filter is vibrated, a potential difference is generated in the direction for the toner to move from the developer carrier to the image carrier, the developer carrier is rotated in a reverse direction to that at image forming time, and the image carrier is rotated in the same direction as that at the image forming time, so that scattered toner, which has dropped from the filter and adhered to the developer carrier, is recovered by the cleaning unit via the image carrier.

Abstract: An image forming apparatus includes a transfer processing portion, a detection processing portion, a correction processing portion, and an adjustment processing portion. The transfer processing portion transfers a detection toner image to outside an output area of a transfer object to which a toner image as an output target is transferred from an image-carrying member. The detection processing portion detects a density of the detection toner image that has been transferred to the transfer object by the transfer processing portion. The correction processing portion corrects a detection result of the detection processing portion based on an amount of toner transferred from the image-carrying member to the output area at a transfer timing when the detection toner image is transferred. The adjustment processing portion adjusts an image forming condition based on the detection result after correction by the correction processing portion.

Abstract: A processor causes a printing portion to execute, when first conveying processing is executed, test print processing for executing processing of forming a plurality of test toner images on a sheet under a print condition that differs for each of the plurality of test toner images. The processor acquires a plurality of first sensing densities when the first conveying processing is executed. The processor causes the printing portion to execute the test print processing when second conveying processing is executed. The processor acquires a plurality of second sensing densities when the second conveying processing is executed. The processor compares the plurality of first sensing densities and the plurality of second sensing densities to adjust the print condition in the print processing when the second conveying processing is executed.

Abstract: An image forming apparatus includes a transfer processing portion, a detection processing portion, a correction processing portion, and an adjustment processing portion. The transfer processing portion transfers a detection toner image to outside an output area of a transfer object to which a toner image as an output target is transferred from an image-carrying member. The detection processing portion detects a density of the detection toner image that has been transferred to the transfer object by the transfer processing portion. The correction processing portion corrects a detection result of the detection processing portion based on an amount of toner transferred from the image-carrying member to the output area at a transfer timing when the detection toner image is transferred. The adjustment processing portion adjusts an image forming condition based on the detection result after correction by the correction processing portion.

Abstract: An image forming apparatus includes a developing current detecting portion, a control portion, and a deviation detecting portion. The developing current detecting portion detects a developing current that flows between a developing device and a photoconductor drum during development of an electrostatic latent image. The control portion causes the exposure device to form electrostatic latent images of at least two patch images at different positions from each other and at different timings from each other in a main scanning direction. The deviation detecting portion detects deviation of one of the exposure device and the photoconductor drum with respect to the other based on a detection timing at which the developing current is detected during development of the electrostatic latent images of the at least two patch images.

Abstract: In an image forming apparatus, a bias controller varies one, while keeping the other fixed, of a charging alternating-current frequency, which is the frequency of the charging alternating-current voltage, and a developing alternating-current frequency, which is the frequency of the developing alternating-current voltage. Specifically, in a case where interference fringes appear in a developed image due to interference between the charging and developing alternating-current frequencies, when the recognizable minimum pitch of the interference fringes is A1 (mm), the width of the variation region of the other frequency is B1 (Hz), the rotation speed of an image carrying member is C1 (mm/sec), and the variation speed of the other frequency in the variation region is D1 (Hz/sec), the bias controller varies the other frequency at a variation speed D1 that fulfills |D1|>B1/(A1/C1).

Abstract: An image forming apparatus has a bias controller. The bias controller varies both a charging alternating-current frequency, which is the frequency of a charging alternating-current voltage, and a developing alternating-current frequency, which is the frequency of the developing alternating-current voltage. When the region of the charging and developing alternating-current frequencies in which interference fringes appear in a developed image due to interference between the charging and developing alternating-current frequencies is taken as a variation region and the variation speeds of the charging and developing alternating-current frequencies in the variation region are taken as a first and a second variation speed respectively, the bias controller varies the charging and developing alternating-current frequencies such that one of the first and second variation speeds is a positive-number multiple of the other.

Abstract: In an image forming apparatus, a bias controller varies one, while keeping the other fixed, of a charging alternating-current frequency, which is the frequency of the charging alternating-current voltage, and a developing alternating-current frequency, which is the frequency of the developing alternating-current voltage. Specifically, in a case where interference fringes appear in a developed image due to interference between the charging and developing alternating-current frequencies, when the recognizable minimum pitch of the interference fringes is A1 (mm), the width of the variation region of the other frequency is B1 (Hz), the rotation speed of an image carrying member is C1 (mm/sec), and the variation speed of the other frequency in the variation region is D1 (Hz/sec), the bias controller varies the other frequency at a variation speed D1 that fulfills |D1|>B1/(A1/C1).

Abstract: An image forming apparatus has a bias controller. The bias controller varies both a charging alternating-current frequency, which is the frequency of a charging alternating-current voltage, and a developing alternating-current frequency, which is the frequency of the developing alternating-current voltage. When the region of the charging and developing alternating-current frequencies in which interference fringes appear in a developed image due to interference between the charging and developing alternating-current frequencies is taken as a variation region and the variation speeds of the charging and developing alternating-current frequencies in the variation region are taken as a first and a second variation speed respectively, the bias controller varies the charging and developing alternating-current frequencies such that one of the first and second variation speeds is a positive-number multiple of the other.

Abstract: In an image forming apparatus, a resistance component of an inner impedance of an electricity removing member is equal to or lower than a value that is obtained by multiplying a calculated resistance value by a first specific value, the calculated resistance value being calculated based on a predetermined formula as a DC resistance value of the electricity removing member that is required to reduce a pre-electricity-removal potential of a photoconductor to a predetermined post-electricity-removal potential during an electricity removal time, the first specific value being calculated based on a ratio of a linear speed of the electricity removing member to a linear speed of the photoconductor, and a resistance component of the contact impedance of the electricity removing member is equal to or lower than a value that is obtained by multiplying the calculated resistance value by a second specific value that is calculated based on the ratio.

Abstract: In an image forming apparatus, a resistance component of an inner impedance of an electricity removing member is equal to or lower than a value that is obtained by multiplying a calculated resistance value by a first specific value, the calculated resistance value being calculated based on a predetermined formula as a DC resistance value of the electricity removing member that is required to reduce a pre-electricity-removal potential of a photoconductor to a predetermined post-electricity-removal potential during an electricity removal time, the first specific value being calculated based on a ratio of a linear speed of the electricity removing member to a linear speed of the photoconductor, and a resistance component of the contact impedance of the electricity removing member is equal to or lower than a value that is obtained by multiplying the calculated resistance value by a second specific value that is calculated based on the ratio.

Abstract: A developing device includes a developing roller and a developing magnetic pole. The developing roller is disposed to face an image carrier across a predetermined gap. The developing magnetic pole is provided in the developing roller so as to be displaced between first and second magnetic pole positions. When the developing magnetic pole is at the first magnetic pole position, a magnetic field is generated at a first position in the gap. When the developing magnetic pole is at the second magnetic pole position, a magnetic field is generated at a second position in the gap. When a circumferential speed ratio of the developing roller to the image carrier is increased, the developing magnetic pole is displaced toward the second magnetic pole position, and when the circumferential speed ratio is decreased, the developing magnetic pole is displaced toward the first magnetic pole position.

Abstract: An image forming apparatus includes a photoconductor and an electricity removing member electrically grounded and disposed to be in contact with a surface of the photoconductor. In the image forming apparatus, with regard to a capacitance component of an inner impedance of the electricity removing member and a capacitance component of a contact impedance of the electricity removing member that are calculated from a Cole-Cole plot obtained from measurement by an AC impedance method in a predetermined frequency range, a value obtained by dividing the capacitance component of the contact impedance by the capacitance component of the inner impedance is equal to or lower than a predetermined first specific value, and the capacitance component of the inner impedance is equal to or lower than a predetermined second specific value.

Abstract: A developing device includes a developing roller and a developing magnetic pole. The developing roller is disposed to face an image carrier across a predetermined gap. The developing magnetic pole is provided in the developing roller so as to be displaced between first and second magnetic pole positions. When the developing magnetic pole is at the first magnetic pole position, a magnetic field is generated at a first position in the gap. When the developing magnetic pole is at the second magnetic pole position, a magnetic field is generated at a second position in the gap. When a circumferential speed ratio of the developing roller to the image carrier is increased, the developing magnetic pole is displaced toward the second magnetic pole position, and when the circumferential speed ratio is decreased, the developing magnetic pole is displaced toward the first magnetic pole position.