Abstract: An image forming apparatus includes a first power cord configured to supply a first power, a second power cord configured to supply a second power, a first monitor configured to monitor a supply state of the first power, a second monitor configured to monitor a supply state of the second power, a load to which either the first power or the second power can be supplied, a controller configured to control an operation of the load, and a switcher configured to be switched between a first state in which the first power is supplied to the controller and a second state in which the second power is supplied to the controller.

Abstract: An image forming apparatus includes a connector, a conveyance unit, and a controller. The conveyance unit includes first and second sensors, first and second light sources, and a capacitor. Based on the first and second sensors, the controller determines a position of a paper jam having occurred during an image formation job. The first light source is turned-on when the position of the paper jam corresponds to a position of the first sensor and the second light source is turned-on when the position of the paper jam corresponds to a position of the second sensor. When the conveyance unit is pulled out of the image forming apparatus, the connector shuts off the electrical connection between the conveyance unit and a power source, and a light source controlled to turn on by the controller glows based on electric power accumulated in the capacitor during the image formation job.

Abstract: A developing device includes a developer carrying member configured to carry a developer, containing toner and a carrier, for developing an electrostatic latent image formed on an image bearing member, a developer container configured to accommodate the developer, and an oscillation circuit including a resonance circuit including a coil and a circuit portion containing a capacitor and configured to oscillate a signal for detecting a toner concentration of the developer accommodated in the developer container. The coil is formed integrally with the developer container by a metal film, and the coil is disposed on an inner wall surface of the developer container.

Abstract: An image forming apparatus includes a connector, a conveyance unit, and a controller. The conveyance unit includes first and second sensors, first and second light sources, and a capacitor. Based on the first and second sensors, the controller determines a position of a paper jam having occurred during an image formation job. The first light source is turned-on when the position of the paper jam corresponds to a position of the first sensor and the second light source is turned-on when the position of the paper jam corresponds to a position of the second sensor. When the conveyance unit is pulled out of the image forming apparatus, the connector shuts off the electrical connection between the conveyance unit and a power source, and a light source controlled to turn on by the controller glows based on electric power accumulated in the capacitor during the image formation job.

Abstract: A developing device includes a developer carrying member for carrying a developer, containing toner and a carrier, for developing an electrostatic latent image formed on an image bearing member; a developer container for accommodating the developer; and an oscillation circuit including a resonance circuit constituted by a coil and a circuit portion containing a capacitor and for oscillating a signal for detecting a toner concentration of the developer accommodated in the developer container. The coil is formed on an inner wall surface of the developer container.

Abstract: An image forming apparatus that is capable of determining whether a measurement image is formed normally. First and second image forming units form first and second images on an image bearing member using first and second color toners. Reflectance of first toner is higher than the image bearing member and is higher than the second toner. A controller controls image forming units to form first and second measurement images superimposed. A correction unit corrects a positional relationship between the first and second images based on a position of the first measurement image detected based on an output timing of a signal indicating that the received light amount is not less than a threshold. A prohibition unit prohibits the correction unit from correcting the positional relationship when a period during which the signal is output is different from a predetermined period.

Abstract: An image forming apparatus that is capable of determining whether a measurement image is formed normally. First and second image forming units form first and second images on an image bearing member using first and second color toners. Reflectance of first toner is higher than the image bearing member and is higher than the second toner. A controller controls image forming units to form first and second measurement images superimposed. A correction unit corrects a positional relationship between the first and second images based on a position of the first measurement image detected based on an output timing of a signal indicating that the received light amount is not less than a threshold. A prohibition unit prohibits the correction unit from correcting the positional relationship when a period during which the signal is output is different from a predetermined period.

Abstract: Provided is an image forming system having a first image forming apparatus and a second image forming apparatus, the image forming system including: a first image forming unit provided to the first image forming apparatus and forming an image on a first surface of a recording sheet; and a second image forming unit provided to the second image forming apparatus and forming an image on a second surface of the recording sheet on the first surface of which the image has been formed by the first image forming unit, in which, when the first image forming unit and the second image forming unit form pattern images for image position adjustment on the recording sheet, the first image forming unit and the second image forming unit form a first pattern image and a second pattern image on the same surface of the recording sheet.

Abstract: Provided is an image forming system having a first image forming apparatus and a second image forming apparatus, the image forming system including: a first image forming unit provided to the first image forming apparatus and forming an image on a first surface of a recording sheet; and a second image forming unit provided to the second image forming apparatus and forming an image on a second surface of the recording sheet on the first surface of which the image has been formed by the first image forming unit, in which, when the first image forming unit and the second image forming unit form pattern images for image position adjustment on the recording sheet, the first image forming unit and the second image forming unit form a first pattern image and a second pattern image on the same surface of the recording sheet.

Abstract: Data concerning misalignment of beams is measured and held in an optical scanning apparatus before the optical scanning apparatus is incorporated in an image forming apparatus. The optical scanning apparatus includes a light source for emitting multiple beams, an optical lens for converting the multiple beams to parallel lights and a rotating polygon mirror for rotary-deflecting the multiple beams. Furthermore, the measurement apparatus measures main scanning direction misalignment among the multiple beams on a photosensitive member provided for the image forming apparatus, which has been determined by detecting the multiple beams from the rotating polygon mirror (and an f? lens). The optical scanning apparatus includes a holding unit for holding the data concerning misalignment. The image forming apparatus in which the optical scanning apparatus is incorporated corrects the misalignment with the use of the data concerning misalignment inputted directly or indirectly from the holding unit.

Abstract: An image forming apparatus includes light source having multiple light-emitting portions, rotating polygonal mirror which deflects a beam that is emitted from light source, and photosensitive member which is exposed by beams in an image period that is included in one scanning cycle of the beam. One scanning cycle of the beam includes an image period and a non-image period. This apparatus includes selection unit which selects one or more light-emitting portions to be used in image period from among multiple light-emitting portions, and driving unit which drives selected light-emitting portions to emit a beam in a non-image period that is immediately before image period. This apparatus further includes control unit which executes auto light power control for one or more light-emitting portions to be used in image period according to light power of beams detected by beam detection unit.

Abstract: An image forming apparatus includes a photosensitive member, a light source for which intervals between spots formed on the photosensitive member by respective beams emitted from a plurality of light-emitting portions are narrower than a predetermined resolution, and a rotating polygonal mirror having a plurality of mirror plane each of which deflects beams emitted from the light source while rotating. In particular, the image forming apparatus includes a selection unit which selects a light-emitting portion corresponding to a mirror plane used to deflect a beam from the light source, and a driving unit which drives the light source to emit a beam from the selected light-emitting portion.

Abstract: An image forming apparatus has a water content determination apparatus that can precisely determining a water content in a medium regardless of an environment where the image forming apparatus is installed. The water content determination apparatus has a detection device that outputs a first signal while the medium is absent in an electrostatic capacitance region formed in a path where the medium is conveyed and outputs a second signal while the medium is present in the electrostatic capacitance region. The temperature in the image forming apparatus is determined based on the first signal. The water content in the medium is determined based on the second signal and the temperature determined by the temperature determination device.

Abstract: A frequency modulator which employs a method in which the frequency of an image clock is modulated by a predetermined amount of fluctuation to thereby reduce noise, and is capable of providing images free from color shift caused by frequency modulation. A frequency controller of the frequency modulator generates frequency-modulated image clocks associated with images formed by respective lasers, and the frequency change profiles of the respective frequency-modulated image clocks are controlled such that they are identical with respect to the positions of the images formed by the respective lasers.

Abstract: An image forming apparatus includes light source having multiple light-emitting portions, rotating polygonal mirror which deflects a beam that is emitted from light source, and photosensitive member which is exposed by beams in an image period that is included in one scanning cycle of the beam. One scanning cycle of the beam includes an image period and a non-image period. This apparatus includes selection unit which selects one or more light-emitting portions to be used in image period from among multiple light-emitting portions, and driving unit which drives selected light-emitting portions to emit a beam in a non-image period that is immediately before image period. This apparatus further includes control unit which executes auto light power control for one or more light-emitting portions to be used in image period according to light power of beams detected by beam detection unit.

Abstract: An image forming apparatus includes a photosensitive member, a light source for which intervals between spots formed on the photosensitive member by respective beams emitted from a plurality of light-emitting portions are narrower than a predetermined resolution, and a rotating polygonal mirror having a plurality of mirror plane each of which deflects beams emitted from the light source while rotating. In particular, the image forming apparatus includes a selection unit which selects a light-emitting portion corresponding to a mirror plane used to deflect a beam from the light source, and a driving unit which drives the light source to emit a beam from the selected light-emitting portion.

Abstract: An image forming apparatus in which the intensity of a light beam used to form a latent image is switched in response to a change in resolution. A laser emits a light beam for forming a latent image on a photosensitive drum. A polygon mirror scans the emitted light beam. BD sensors detect the scanned beam. A timing controller selects the preferable timing from a storage device table according to the intensity of the light beam or the resolution when controlling the light emission timing of the lasers in response to a detection of timing of the detected light beam.

Abstract: An image forming apparatus which includes image forming units of a plurality of colors, each having an image carrier and a light beam scanning portion for polarizing irradiated laser beam by a polygon mirror and forming an electrostatic latent image on the image carrier, and forms a color image by superposing images formed by the image forming unit, includes a first control portion which controls the velocity of rotation of one polygon mirror in one image forming unit, a second control portion which controls rotation of another polygon mirror by velocity control or phase control in another image forming unit, and a control signal generation portion which, when the rotation velocity of another polygon mirror reaches a target velocity by velocity control of the second control portion, generates a rotation reference signal based on the driving information of one polygon mirror driven by velocity control of the first control portion, or detection information of the laser beam polarized by one polygon mirror, wher

Abstract: Data concerning misalignment of beams is measured and held in an optical scanning apparatus before the optical scanning apparatus is incorporated in an image forming apparatus. The optical scanning apparatus includes a light source for emitting multiple beams, an optical lens for converting the multiple beams to parallel lights and a rotating polygon mirror for rotary-deflecting the multiple beams. Furthermore, the measurement apparatus measures main scanning direction misalignment among the multiple beams on a photosensitive member provided for the image forming apparatus, which has been determined by detecting the multiple beams from the rotating polygon mirror (and an f? lens). The optical scanning apparatus includes a holding unit for holding the data concerning misalignment. The image forming apparatus in which the optical scanning apparatus is incorporated corrects the misalignment with the use of the data concerning misalignment inputted directly or indirectly from the holding unit.

Abstract: An image forming apparatus which includes image forming units of a plurality of colors, each having an image carrier and a light beam scanning portion for polarizing irradiated laser beam by a polygon mirror and forming an electrostatic latent image on the image carrier, and forms a color image by superposing images formed by the image forming unit, includes a first control portion which controls the velocity of rotation of one polygon mirror in one image forming unit, a second control portion which controls rotation of another polygon mirror by velocity control or phase control in another image forming unit, and a control signal generation portion which, when the rotation velocity of another polygon mirror reaches a target velocity by velocity control of the second control portion, generates a rotation reference signal based on the driving information of one polygon mirror driven by velocity control of the first control portion, or detection information of the laser beam polarized by one polygon mirror, wher