Patent application number | Description | Published |
20110298884 | IMAGE FORMING APPARATUS - An image forming apparatus capable of reducing density variation that occurs in an output image when the rotational speed of a polygon mirror is changed. A light source emits a light beam for forming an electrostatic latent image on a photosensitive drum. The polygon mirror deflects the light beam such that the light beam moves on the photosensitive drum in a predetermined direction. A polygon mirror control circuit controls the polygon mirror such that when the toner image is to be formed at a first magnification, the rotational speed of the polygon mirror is made higher than when the toner image is to be formed at a second magnification that is larger than the first magnification. When the toner image is to be formed at the first magnification, the light beam becomes smaller in light amount than when the toner image is to be formed at the second magnification. | 12-08-2011 |
20120001995 | EXPOSURE DEVICE CAPABLE OF STABILIZING DENSITY OF IMAGE FORMED BY MULTIPLE EXPOSURE AND IMAGE FORMING APPARATUS EQUIPPED WITH THE EXPOSURE DEVICE - An exposure device configured to perform exposure using a plurality of light beams and capable of stabilizing image density without increasing circuit size. The exposure device has a first light source for emitting a first light beam and a second light source for emitting a second light beam. The exposure device exposes a photosensitive drum such that areas exposed to the respective first and second light beams at least partially overlap each other. A first drive current having a predetermined value and a second drive current are supplied to the respective first and second light sources. A photodiode detects the intensities of the respective first and second light beams or the sum of the intensities. The second drive current is controlled based on a detection result from the photodiode such that the sum of the intensities becomes equal to a target intensity. | 01-05-2012 |
20130106973 | ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS | 05-02-2013 |
20130162998 | IMAGE FORMING APPARATUS AND CONTROL METHOD OF IMAGE FORMING APPARATUS - An image forming apparatus includes an image forming unit configured to form a measurement image on a sheet, a measurement unit configured to measure the measurement image formed on the sheet to output a measurement value, a white reference plate provided at a position facing to the measurement unit, and a correction unit configured to correct the measurement value output from the measurement unit according to a distance from the measurement unit to the white reference plate in a case where the measurement image formed on the sheet is measured. | 06-27-2013 |
20130208068 | ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD - An image forming apparatus using the laser scan method or the LED method, which is capable of reducing a variation of spot diameter with a simple mechanism, and of forming a high-quality image by adjusting the density depending on the image resolution with a low cost. The image forming apparatus forms an image by developing an electrostatic latent image formed by irradiating a charged photoconductor with light emitted from a light source with developer. A detecting unit detects a distance between an attention pixel and an adjacent image that is adjacent to an image including the attention pixel across a white background. An adjustment unit adjusts a density of the attention pixel based on the distance measured with the detecting unit and a spot diameter of the light on a surface of the photoconductor. | 08-15-2013 |
20130286133 | IMAGE FORMING APPARATUS CAPABLE OF CORRECTING RELATIVE POSITION BETWEEN LASER BEAMS - An image forming apparatus capable of correcting relative position in exposure position between laser beams that scan a photosensitive drum in a scanning direction of the laser beams. A semiconductor laser includes first and second light emitting elements for emitting first and second laser beams. These elements are arranged such that the laser beams expose positions on the photosensitive drum different in the sub scanning direction. A polygon mirror deflects the laser beams to scan the photosensitive drum. Relative position in the scanning direction between images to be formed on the photosensitive drum by exposure by the first and second laser beams is corrected based on correction data. An image data generation section generates drive signals associated with the respective light emitting elements. A semiconductor laser drive circuit causes the semiconductor laser to emit the first and second laser beams, based on the drive signals. | 10-31-2013 |
20130286143 | LIGHT SCANNING APPARATUS AND IMAGE FORMING APPARATUS INCLUDING LIGHT SCANNING APPARATUS - A resin BD lens having a property of refracting a light beam in a direction corresponding to a main scanning direction may cause a variation in generation timing difference among a plurality of horizontal synchronization signals and accordingly degrade accuracy to correct the starting position of an electrostatic latent image. The present invention uses a glass BD lens having a property of refracting a light beam in a direction corresponding to the main scanning direction. | 10-31-2013 |
20130342627 | IMAGE FORMING APPARATUS - An image forming apparatus includes a light source including a plurality of light emitting elements for emitting a light beam for exposing the photosensitive member, the light emitting elements being arranged respectively corresponding to one pixel of the image in a direction of a rotational axis of the photosensitive member, an output unit for outputting pixel data for driving each of the light emitting elements, a drive unit for driving the light emitting elements based on the output pixel data, a storage unit for storing a cumulative number of times of light emission of a target light emitting element included in the light emitting elements, and a light amount control unit for controlling a light amount of a light beam emitted by the target light emitting element and the other light emitting elements based on the stored cumulative number of times of light emission of the target light emitting element. | 12-26-2013 |
20140050496 | IMAGE FORMING APPARATUS FOR FORMING A MEASUREMENT IMAGE - An image forming apparatus includes an image forming unit configured to form a measurement image on a sheet, a measurement unit configured to radiate light on the measurement image via a transparent window, and measure the light reflected from the measurement image, a white reference plate of which a white level is measured by the measurement unit, a black member of which a black level is measured by the measurement unit, and a determination unit configured to determine, based on a change in a measurement result of the white reference plate and a change in a measurement result of the black member measured by the measurement unit, whether the white reference plate, the black member, or the window is soiled. | 02-20-2014 |
20140056601 | IMAGE FORMING APPARATUS FOR FORMING A MEASUREMENT IMAGE - An image forming apparatus includes a measurement unit configured to irradiate a measurement image with light, and measure the light reflected from the measurement image, a white reference plate disposed in a position opposite to the measurement unit, a correction unit configured to correct a measurement result of the measurement image, based on a measurement result of the white reference plate acquired by the measurement unit, and a temperature detection unit configured to detect temperature in a vicinity of the measurement unit, wherein the correction unit corrects, in a case where a difference between a temperature detected by the temperature detection unit and a temperature shown when previously measuring the white reference plate is less than a predetermined value, a measurement result of the measurement image using a previous measurement result of the white reference plate without measuring the white reference plate with the measurement unit. | 02-27-2014 |
20140248063 | IMAGE FORMING APPARATUS THAT DETECTS PHASE OF PHOTOSENSITIVE DRUM - An image forming apparatus which reduces a time period required to detect a phase of a photosensitive drum without an increase in costs. The apparatus performs exposure control according to a phase of rotation of the drum. A reference position serving as a reference for rotation of the drum is detected when the drum is rotating at a predetermined speed. After the speed of the drum is reduced from the predetermined speed, a first time period is measured which has elapsed from detection of the reference position to stoppage of rotation of the drum. After rotation of the drum is started again, a third time period is measured which has elapsed from reaching of the predetermined speed to detection of the reference position. The phase of the photosensitive drum for performing the control is determined based on the first time period and the third time period. | 09-04-2014 |