Patent application number | Description | Published |
20100189453 | IMAGE FORMING APPARATUS - A write reference signal generating unit uses horizontal synchronization signals output from BD sensors to generate, for each laser scanning unit of respective image forming units, a main scanning write reference signal for irradiating laser light from a semiconductor laser every other predetermined number of reflective surfaces when photosensitive drums are driven to rotate at a second speed of rotation which is slower than a standard speed of rotation. A phase adjustment unit adjusts the phase of a control signal for driving a polygonal mirror, which is output to a polygon motor of each image forming unit, on the basis of a relative time difference between image write timings of the respective laser scanning units as measured by a time difference measurement unit. | 07-29-2010 |
20100226672 | IMAGE FORMING APPARATUS - An image forming apparatus has a first light controller to shift starts of image writing operations of light sources by a first time interval. A test data storage stores, beforehand, test image data having dot columns formed by one-dot images arranged in a row in a sub-scanning direction and at predetermined intervals in a main scanning direction. An operation controller controls an image carrier at a speed so that adjacent dot images in the sub-scanning direction overlap. A second light controller forms electrostatic latent test images on the image carrier based on timing signals with the image carrier moved by the operation controller, and draws electrostatic latent test images with different time intervals. A density measurer measures densities of the developed test images. A time interval adjusting section adjusts the time interval based on the time interval used to draw the electrostatic latent test image having the lowest measured density. | 09-09-2010 |
20110188891 | IMAGE FORMING APPARATUS AND IMAGE MAGNIFICATION ADJUSTMENT METHOD - An image forming apparatus has an intermediate transfer belt stretched lightly across rollers to move endlessly in a sub-scanning direction upon image formation and has an outer surface to which a toner image formed by a development unit is transferred. A secondary transfer opposing roller is one of the rollers across which the intermediate transfer belt is stretched. A secondary transfer roller contacts the outer surface of the intermediate transfer belt and transfers the toner image on the intermediate transfer belt to recording paper. A movement mechanism moves at least one of the rollers or the secondary transfer roller and changes a pressed state of the intermediate transfer belt by the secondary transfer roller at a nip of the secondary transfer opposing roller and the secondary transfer roller. A movement mechanism control unit controls a travel distance of the roller to be moved by the movement mechanism. | 08-04-2011 |
20120162670 | MULTI-BEAM IMAGE FORMING APPARATUS AND ELECTROSTATIC LATENT IMAGE FORMATION METHOD - An image forming apparatus includes a pattern formation control unit for forming a plurality of evaluation patterns by repeatedly turning on and off a plurality of light emitters arranged in a row in units of n dots (n is an integer equal to or greater than 1) to irradiate light to a photoconductor while changing write timings of the respective light emitters in a predetermined range, an adjustment unit for improving reliability of density difference information among the plurality of evaluation patterns, and a determination unit for obtaining information on densities of the respective evaluation patterns based on a detection result on the densities of the respective evaluation patterns and determining write timings derived from the evaluation pattern having the lowest or highest density as the write timings of the plurality of light emitters. | 06-28-2012 |
20130222508 | OPTICAL UNIT, LIGHT SCANNING DEVICE, AND IMAGE FORMING APPARATUS - A light scanning device includes an optical unit. The optical unit includes a polygon mirror and a polygon motor. The polygon mirror includes n (n is an integer equal to or larger than 1) mirror surfaces and guides light in a main scanning direction of an image bearing member. The polygon motor includes m (m is an integer equal to or larger than 1 and is coprime with n) poles and rotates the polygon mirror. | 08-29-2013 |
20130222512 | IMAGE FORMING APPARATUS - An image forming apparatus includes a photosensitive body, an exposure unit, a pulse generating unit, a smoothing unit, a drive current generating unit, and a second emitting control unit. The exposure unit includes a light source for emitting a light beam, and causes the light beam emitted from the light source to perform scanning in a main scanning direction, thereby drawing a main scanning line on the photosensitive body. The second emitting control unit causes the light source to emit the light beam, in an APC period of automatically controlling the light quantity of the light beam, by causing the pulse generating unit to generate a pulse signal having a duty ratio of 100 percent, causing the smoothing unit to smooth the pulse signal thereby generating an analog signal, and causing the drive current generating unit to generate a drive current based on the analog signal. | 08-29-2013 |
20130222864 | IMAGE FORMING APPARATUS - An image forming apparatus includes an exposing section, a pulse generating section, a frequency storing section, an emission control section, a smoothing section, and a driving-current generating section. The pulse generating section generates a periodic pulse signal indicating light amount of light beam emitted by a light source of the exposing section. The frequency storing section stores in advance a plurality of frequencies of the pulse signal. The emission control section selects, in the rendering of each main scanning line, any one of the plurality of frequencies and instructs the pulse generating section to generate the pulse signal having the selected frequency. The smoothing section smoothes the pulse signal generated by the pulse generating section according to the instruction of the emission control section and generates analog signal. The driving-current generating section generates driving current for the light source of the exposing section on the basis of the analog signal. | 08-29-2013 |
20130235141 | IMAGE FORMING APPARATUS - Image forming apparatus includes elements as follows. Light-amount storing section stores, in the main scanning line divided into a plurality of blocks, light amounts of a light beam irradiated on the blocks. Change-data storing section stores a plurality of change data items set in the vicinity of each of block boundaries of the plurality of blocks. The plurality of change data items are used to cope with each of a plurality of events that are likely to affect the image quality in the vicinity of the block boundary. Irradiation control section selects, out of the plurality of change data items, change data for coping with an event selected out of the plurality of events and instructs Pulse generating section to generate, in the vicinity of the block boundary, pulse signal from which analog signal indicating a change in a value represented by the selected change data is obtained. | 09-12-2013 |