Ricoh Company, Ltd.

Dai Nippon Printing Co., Ltd.

Yoshiki Yoshida

Hitomu Watanabe

Kenichirou Asada

Shinji Kobayashi

Hiroshi Sekiguchi

Kan Tomita

Yuji Yasuda

Takashi Mama

Fumihiro Miyagawa

Kumpei Oda

Kiyoto Nagasawa

Takanobu Fujioka

Hidetoshi Kanai

Masahiro Goto

Kazuo Murai

Yoshinobu Kagami

A determining unit determines whether a difference between a temperature value and a temperature detected by a temperature detecting unit is equal to or larger than a first value. A pattern forming unit, when the determining unit determines that the difference is equal to or larger than the first value, forms a pattern for measurement including sub-patterns of a plurality of colors on a transfer medium. A calculating unit calculates a misregistration-amount for each sub-pattern based on a detected position of the sub-pattern and a predetermined position of the sub-pattern. A correcting unit corrects a position on which the sub-pattern is to be formed based on the misregistration-amount. An image forming unit forms an image for each color factoring in corrected position for each color.

Image forming apparatus and method of correcting color misregistration in image forming apparatus

An image forming apparatus includes an image forming mechanism configured to perform an image processing operation for forming a plurality of elementary-color images, superposing the plurality of elementary-color images sequentially and accurately into a single color image on a transfer medium, and transferring the single color image onto a recording sheet. An error correction mechanism is configured to perform a plurality of different recording error corrections for correcting different recording errors in a main scanning direction and a sub scanning direction during a time interval between the image processing operations on the recording sheet and on a following recording sheet. And, a selector is configured to activate at least two of the plurality of different recording error corrections.

Method and apparatus for image forming capable of effectively correcting alignment errors of elementary color outputs to be superposed into an image

An image forming apparatus is capable of forming a clear image by using laser beams projected from a plurality of laser light sources. The image forming apparatus forms an electrostatic latent image on a medium to be scanned by laser beams, which are projected from a plurality of laser light sources and periodically deflected by a rotational deflecting unit, so that the laser beams scan the medium, which is uniformly charged and moving in a sub-scanning direction, in a main-scanning direction perpendicular to the sub-scanning direction. A pixel clock generating unit generates pixel clocks, which are used for controlling timings of projection of the laser beams, separately for each of the laser light sources, and for performing a phase change of each of the pixel clocks; and a phase control unit that controls independently each of the pixel clocks.

Image forming apparatus, an optical scanning apparatus and an image forming method

An image forming apparatus including a memory device configured to prestore control information and registration pattern data, a traveling member, a toner pattern forming device forming a toner pattern, which includes a plurality of marks of a plurality of color components, on the traveling member according to the registration pattern data. A position detecting device detects each of the plurality of marks in the toner pattern. A control information correcting device corrects the control information according to a difference among positions of the plurality of marks, and a main-scan registration correcting device adjusts, based on the corrected control information, a start-of-write timing in the main scanning direction in a unit of a pixel clock cycle and adjusts a writing timing in the main scanning direction in a unit smaller than the pixel clock cycle by controlling a phase of the pixel clock cycle.

Method and apparatus for forming images capable of reducing color registration errors

A color image forming apparatus includes a pattern forming mechanism configured to form a pattern for fine adjustment and a pattern for rough adjustment on a transfer medium, a detection mechanism configured to detect the pattern formed thereon, a displacement calculation mechanism configured to obtain a predetermined value and preset reference values, to calculate the amount of displacement based on the detected pattern and the preset reference values, and to determine whether or not the amount of the displacement is equal to or less than the predetermined value, and a displacement correction mechanism configured to correct the displacement based on the calculation.

Apparatus, method, and program for color image forming capable of efficiently correcting displacement

An optical scanning apparatus provides improved image quality by changing the amount of writing scale compensation for a pixel clock during a scanning cycle. A pixel clock generation unit of the optical scanning apparatus divides the scanning cycle into multiple division periods. A phase change of the pixel clock is carried out for each of the division periods. The phase change can also be different from scanning cycle to scanning cycle.

Optical scanning apparatus and an image formation apparatus therewith

The present invention provides a Fresnel lens sheet capable of successfully avoiding the 'collapse', 'abrasion' and &#x201c;moire&#x201d; problems. A Fresnel lens sheet constitutes, together with a lenticular lens sheet, a rear projection screen, which is mounted in the frame of a rear projection type display. The Fresnel lens sheet includes, on one surface of its substrate, a Fresnel lens part containing a plurality of lenses concentrically formed on one plane. The apexes of the lenses situated in the area between the center and the outer edge of the Fresnel lens part are flattened to give flat faces, and the widths of the flat faces of the lenses on the outer edge side are made greater than the widths of the flat faces of the lenses on the center side. The widths of the flat faces of the lenses are from 0 to 30 &#x3bc;m.

Fresnel lens sheet

An image-forming apparatus is disclosed that includes at least one imaging optical system forming an electrostatic latent image on the scanning surface of a medium moving in a sub scanning direction by scanning the scanning surface in a main scanning direction by periodically deflecting a laser beam with a rotary deflector, a pixel clock generation part generating a pixel clock signal for controlling the emission timing of the laser beam and changing the phase of the pixel clock signal, a region setting part setting the length of each of multiple regions based on image writing magnifications in a line in the main scanning direction, the regions being formed by dividing part of the scanning surface corresponding to the line in the main scanning direction, and a phase control part controlling the changing of the phase of the pixel clock signal region by region based on the image writing magnifications.

Image-forming apparatus and optical scanner

A projection screencomprises a total reflection prism lensand a lenticular lensprovided on the viewer's side of the total reflection prism lens. The total reflection prism lenshas a plurality of unit prismson its back surface (the outermost plane of incidence) on which imaging light L is incident. Each unit prismhas an apical angle &#x3bb; that corresponds to the angle between the plane of incidenceand the plane of total reflection, and the apical angles &#x3bb; of the unit prismsvary with the position of each unit prismon the screen plane. In particular, the unit prismshave apical angles &#x3bb; varying continuously from 30&#xb0; to 45&#xb0; so that the apical angles &#x3bb; on the side distant from the center O of the concentric circles are greater than the apical angles &#x3bb; on the side close to this center O.

Projection screen and projection display

The present invention provides a Fresnel lens sheet that can, in production using a mold, be easily released from the mold and that scarcely produces stray light upon use, and others. Each prismon the incident side of a Fresnel lens sheetis formed to have a nearly triangular cross section and has a plane of refractionthat refracts projected light S incident on this plane and a plane of total reflectionthat totally reflects, toward the viewer's side, at least part of the light refracted at the plane of refraction. Each prismis made so that a rootbetween a prismand a prismsituated next to the prism, on the plane of total reflection side of the prism(a rootdefined by the plane of refractionof one prismB and the plane of total reflectionof another prismA situated next to the prismB, on the side of the plane of refractionof the prismB) is curved toward the prismA side from the prismB side.

Fresnel lens sheet, process of producing Fresnel lens sheet, mold for use in the production process, and rear projection screen comprising the Fresnel lens sheet

One color is determined as a reference, and adjustment is carried out such that other color is matched with a detection signal generated from a synchronous detector of this color. Each control circuit of other color generates a mark pulse signal by determining an optional position based on a DP generated from each synchronous detector. A reference color control circuit receives a mark signal, and measures time relative to the reference. A CPU checks whether a result of this measurement coincides with a target value. The CPU changes the setting according to the difference, and repeats the measurement until when there is no difference, thereby obtains an adjustment value.

Image formation apparatus and registration method

A lenticular lens sheet having an entrance surface and an exit surface comprises a base part, an entrance lens part forming the entrance surface and having an array of a plurality of convex lens elements capable of gathering light rays. A tinted layer is formed at least in a portion of the entrance lens part near the entrance surface. A light absorbing layer is formed in light-nongathering regions in the exit surface in which light rays refracted by the convex lens elements do not gather.

Lenticular lens sheet and rear projection screen

An image forming apparatus having deflection scanning type and line type exposing devices and first and second developing devices arranged around a photoconductive element, so that parts around the photoconductive element are arranged with ease to promote the miniaturization of the apparatus. The exposing devices are selected based on the principle that the image quality is enhanced for an image of particular color and is lowered for an image of another color expected to be printed less frequently. Specifically, the deflection scanning type exposing device forms the image of the particular color, and the line type exposing device which has an inherently long optical path and simple structure forms the image of another color. Fans are provided to produce cooling air flow to the line type exposing device and to draw out toner dirt and ozone produced by the charger associated therewith. The line type exposing device and the associated charger are electrically insulated from each other and mounted in a common casing. Cleaning elements are provided to clean the charger and the line type exposing device during withdrawal of these elements from the photoconductive element.

Compact BI-color electrophotographic image forming apparatus

A bicolor image forming apparatus having first and second exposing means and first and second developing means arranged around a photoconductive element. The first and second developing means are implemented as a deflection scanning type and a line type, respectively. Parts around a photoconductive element are arranged with ease to promote the miniaturization of the apparatus. This stems from the principle that the image quality may be enhanced for an image of particular color and lowered for an image of another color expected to be printed less frequently. Specifically, the apparatus has deflection scanning type exposing means for forming the image of particular color, and line type exposing means which has an inherently long optical path and simple structure for forming the image of another color.

Growing community of inventors

Kanagawa, Japan

Yoshiki Yoshida