Abstract: To provide an image forming apparatus capable of suppressing an increase in the cost of a process cartridge and capable of reducing image defects caused by replacement of the process cartridge. A process cartridge including a charging roller and a developing unit is attachable to and detachable from an image forming apparatus. A development temperature sensor is disposed in the developing unit. An in-device temperature sensor is disposed outside the process cartridge inside the image forming apparatus. In the case where a temperature detected by the development temperature sensor is lower than a temperature detected by the in-device temperature-humidity sensor, a peak-to-peak voltage of an alternating-current voltage applied to the charging roller is set based on the result of detection by the development temperature sensor.

Abstract: An image forming apparatus includes a temperature/humidity sensor 112 for detecting temperature/humidity information and a controller 101 for executing, on the basis of information detected by this detecting means, an operation in a control mode in which charging by a corona charger 2 and discharging by a discharging means 9 are carried out while rotating a photosensitive member after end of cleaning by the cleaning means and before image formation is started.

Abstract: To provide an image forming apparatus capable of suppressing an increase in the cost of a process cartridge and capable of reducing image defects caused by replacement of the process cartridge. A process cartridge including a charging roller and a developing unit is attachable to and detachable from an image forming apparatus. A development temperature sensor is disposed in the developing unit. An in-device temperature sensor is disposed outside the process cartridge inside the image forming apparatus. In the case where a temperature detected by the development temperature sensor is lower than a temperature detected by the in-device temperature-humidity sensor, a peak-to-peak voltage of an alternating-current voltage applied to the charging roller is set based on the result of detection by the development temperature sensor.

Abstract: An image forming apparatus includes, a unit including at least a photosensitive member and a charging member detachable from a main body of the image forming apparatus, a current detection unit configured to detect a current flowing between the charging member and the photosensitive member, an operation unit configured to be operated by an operator to give an instruction to the image forming apparatus, a display unit provided in the operation unit, and a control unit configured to apply to the charging member a predetermined test voltage having an absolute value greater than a discharge starting voltage based on the instruction from the operation unit, and to perform an operation in a mode for causing the current detection unit to detect a current, wherein the control unit determines, based on the current detected in the mode, whether an error indication is to be given on the display unit.

Abstract: An image forming apparatus includes: a belt; a first image forming unit including a first drum; a second image forming unit including a second drum; a contact-and-separation portion; an executing portion; and a controller for rotating the second drum by a predetermined angle so that when a cycle of an operation is to be repeated N times, a position of the second drum contacting the belt in an (N?1)th cycle differs from a position of the second drum contacting the belt in an Nth cycle, the cycle including receiving the image data in a state that the belt and the first and second drums are at rest and in a stand-by state that the image forming apparatus waits for an input of the image data in the first state, executing the image forming operation, and then returning the image forming apparatus to the stand-by state.

Abstract: Non-uniform charged potential of a surface of a photosensitive member is suppressed even when a temperature of a charging member newly mounted to an image forming apparatus by exchange is lower than a temperature inside the image forming apparatus. The image forming apparatus includes the photosensitive member, a charge portion, an applying portion for applying a charging bias voltage to the charge portion, a toner image forming portion for forming a toner image on the photosensitive member, a transfer portion, a fixing portion, a first casing accommodating them, and a second casing having a recording material accommodating portion for accommodating a recording material.

Abstract: An image forming apparatus includes: a belt; a first image forming unit including a first drum; a second image forming unit including a second drum; a contact-and-separation portion; an executing portion; and a controller for rotating the second drum by a predetermined angle so that when a cycle of an operation is to be repeated N times, a position of the second drum contacting the belt in an (N?1)th cycle differs from a position of the second drum contacting the belt in an Nth cycle, the cycle including receiving the image data in a state that the belt and the first and second drums are at rest and in a stand-by state that the image forming apparatus waits for an input of the image data in the first state, executing the image forming operation, and then returning the image forming apparatus to the stand-by state.

Abstract: Non-uniform charged potential of a surface of a photosensitive member is suppressed even when a temperature of a charging member newly mounted to an image forming apparatus by exchange is lower than a temperature inside the image forming apparatus. The image forming apparatus includes the photosensitive member, a charge portion, an applying portion for applying a charging bias voltage to the charge portion, a toner image forming portion for forming a toner image to the photosensitive member, a transfer portion, a fixing portion, a first casing accommodating them, a second casing having a recording material accommodating portion for accommodating a recording material.

Abstract: A grid of a charging device is cleaned without causing the grid to contact a member to be charged. In this structure, to suppress non-uniform charging due to wear of the grid, which is pulled toward a discharge electrode, for a long time, first and second protective layers are provided. The first protective layer is provided on a surface of a base member of the grid that faces the cleaning member. The second protective layer is provided on a surface of the base member that faces the pressing member. The second protective layer is thicker than the first protective layer.

Abstract: A shutter that suppresses accumulation of discharge products on a photosensitive member is disposed between a grid and the photosensitive member. In this structure, to suppress corrosion of the grid due to the discharge products for a long time, first and second protective layers are provided. The first protective layer is provided on a surface of a base member of the grid that faces the discharge electrode. The second protective layer is provided on a surface of the base member that faces the shutter. The second protective layer is thicker than the first protective layer.

Abstract: An image forming apparatus includes a corona charger configured to charge a photosensitive member surface, an exposure device configured to expose the photosensitive member surface to form an electrostatic image, a developing device configured to develop the electrostatic image with toner to form a toner image, and an execution unit configured to execute a first mode for developing an electrostatic image formed by the exposure device to form a toner image, transferring the toner image onto a recording material, and outputting it, and a second mode for transferring a plurality of toner images formed without substantially forming an electrostatic image using the exposure device onto a recording material as a plurality of adjustment toner images for adjusting a distance between the charger and the photosensitive member surface in a longitudinal direction of the charger, and outputting the plurality of adjustment toner images having average densities different from each other.

Abstract: An image forming apparatus includes, a unit including at least a photosensitive member and a charging member detachable from a main body of the image forming apparatus, a current detection unit configured to detect a current flowing between the charging member and the photosensitive member, an operation unit configured to be operated by an operator to give an instruction to the image forming apparatus, a display unit provided in the operation unit, and a control unit configured to apply to the charging member a predetermined test voltage having an absolute value greater than a discharge starting voltage based on the instruction from the operation unit, and to perform an operation in a mode for causing the current detection unit to detect a current, wherein the control unit determines, based on the current detected in the mode, whether an error indication is to be given on the display unit.

Abstract: An image forming apparatus in which an optical sensor for detecting an adjustment toner image of black color is disposed on an image bearing member and an optical sensor for detecting adjustment toner images of other colors is disposed on an intermediate transfer member. With this configuration, even if the adjustment toner images of black and other colors simultaneously pass through a transfer portion for black color to reduce downtime, it is possible to reduce an effect on the subsequent image caused by light irradiation from the optical sensor and, at the same time, to prevent adjustment toner images of other colors from being excessively retransferred to the image bearing member (for black color) due to discharge. Control is performed such that a voltage less than a discharge start voltage is applied.

Abstract: If the length of an adjustment toner image is longer than a circumferential length of a photosensitive member, a voltage which is less than a discharge start voltage is applied while a region of the photosensitive member irradiated with light by an optical sensor passes through a transfer portion. Further, a voltage which is greater than or equal to the discharge start voltage is applied while the photosensitive member rotates at least once after the region of the photosensitive member irradiated with light by the optical sensor passes through the transfer unit. As a result, density unevenness in the adjustment toner image and a potential change in the photosensitive member due to the optical sensor exposing the adjustment toner image are prevented.

Abstract: An image forming apparatus includes a rotatable image bearing member; a first charging member for electrically charging the image bearing member; a second charging member, provided downstream of the first charging member with respect to a rotational direction of the image bearing member, for electrically charging the image bearing member; an applying device for applying a voltage to the first charging member and the second charging member; a detecting device for a DC current passing through the second charging member; and a controller for controlling, when an AC voltage and a DC voltage are applied to the second charging member while a DC voltage is applied to the first charging member, the DC voltage applied to the second charging member so that an absolute value of the DC current detected by the detecting device is within a predetermined range.

Abstract: A multiply-connecting image forming system in which a second image forming apparatus forms an image on a recording material on which an image has been formed by a first image forming apparatus, the multiply-connecting image forming system suppressing degradation in quality of an output image when only the second image forming apparatus continues duplex image formation because the first image forming apparatus has run out of toner during the duplex image formation.

Abstract: A grid of a charging device is cleaned without causing the grid to contact a member to be charged. In this structure, to suppress non-uniform charging due to wear of the grid, which is pulled toward a discharge electrode, for a long time, first and second protective layers are provided. The first protective layer is provided on a surface of a base member of the grid that faces the cleaning member. The second protective layer is provided on a surface of the base member that faces the pressing member. The second protective layer is thicker than the first protective layer.

Abstract: A shutter that suppresses accumulation of discharge products on a photosensitive member is disposed between a grid and the photosensitive member. In this structure, to suppress corrosion of the grid due to the discharge products for a long time, first and second protective layers are provided. The first protective layer is provided on a surface of a base member of the grid that faces the discharge electrode. The second protective layer is provided on a surface of the base member that faces the shutter. The second protective layer is thicker than the first protective layer.

Abstract: A multiply-connecting image forming system in which a second image forming apparatus forms an image on a recording material on which an image has been formed by a first image forming apparatus, the multiply-connecting image forming system suppressing degradation in quality of an output image when only the second image forming apparatus continues duplex image formation because the first image forming apparatus has run out of toner during the duplex image formation.

Abstract: An image forming system includes a first image forming station including a first toner image forming portion for transferring the toner image onto a sheet, and a first image heating portion; a second image forming station including a second toner image forming portion onto the sheet received from the first image heating portion, and a second image heating portion; a controller capable of executing an operation in a first mode in which a predetermined image formation in accordance with an inputted image forming condition is effected using the first and second image forming stations, a second mode in which it is effected without using the second image forming portion; and a temperature controller for the second image heating portion in the second mode so as to be smaller than a temperature of the second image heating portion in the first mode.