摘要:
An image forming apparatus for forming an image with few defects even when making a copy from a copied image. When forming an image, a standard pattern is formed outside the image forming area in accordance with standard pattern data for color correction. When reading the image together with the standard pattern formed above, the color correction conditions for the image data are modified in accordance with the comparison result between the read standard pattern data and the standard pattern data for color correction. Copying is then performed on a copying paper.
摘要:
In a digital image forming apparatus, when a latent image is formed on a photoconductor by modulating optical intensity of laser beam, the laser beam is emitted in a period of a duty ratio while modulated according to image data, and the image is formed on a sheet of paper. This process is repeated for four colors for a color document. The duty ratio, defined as a ratio of a light-emitting time of a light exposing the photoconductor to a period for exposing a dot, is changed in the same document. For example, the light emission timing pattern is changed between odd and even lines. In another example, the light-emission timings may be changed at least for one of the reproduction colors. The light-emission timing patterns may be provided for each of reproduction colors. The light-emission timing patterns may be changed to have a constant or different screening angle between colors. Image quality of a half-tone image is improved by using such patterns.
摘要:
An image forming apparatus which forms an image according to image data made up of pixel data on colors of pixel constituting an original image, characterized by comprising a color region discriminator for determining to which color region each pixel data belongs, an image region discriminator for determining whether the pixel data belongs to a uniform density region or whether it belongs to an edge portion, a corrective condition deciding unit for determining MTF corrective conditions for the image data of each color region depending on the discrimination results of both the color region discriminator and the image region discriminator, and an MTF correction unit for performing MTF corrections on the image data according to the MTF corrective conditions determined by the corrective condition deciding unit.
摘要:
Pixel data comprising density data of R, G, and B obtained by reading an original with a CCD image sensor are subjected to shading correction by a shading correction unit, and then converted into color region signals H*, V, and C* in the Munsell color space by a first converter. According to the variations of V, a region discriminator determines whether each pixel data belongs to an edge portion of the original image or whether it belongs to a uniform density region of the original image. A noise removing unit performs noise removal by performing smoothing on color region signals H*, V, and C* of the pixel data which have been determined to belong to uniform density regions. A second converter converts the noise-removed color region signals into pixel data of R, G, and B.
摘要:
The individual pattern of each color of the standard pattern is printed on a copy being made, and when the copy is read by a scanner, the image data of the standard pattern are converted into color region signals in a uniform color space by an HVC converter and a C.multidot.H operation unit. In the case where the saturation of the image data has become lower than the standard saturation of the color region, saturation corrective coefficients are determined by a saturation corrective coefficient calculation unit. After the saturation coefficients have been determined for each color of the standard pattern, the image data of the original are read out, and the saturation corrective coefficients for the color region of the image data are used for saturation correction by a saturation correction processing unit. The image data which have been subjected to the saturation correction are reversely converted into the image data of each color by a reverse HVC converter. According to the reversely converted image data, an image is formed on a copying paper.
摘要:
In a digital image forming apparatus, when a latent image is formed on a photoconductor, a light from a light source is emitted in a period of a duty ratio while modulated according to image data, and the latent image is developed and transferred onto a sheet of paper. The duty ratio, defined as a ratio of a light-emitting time of a light exposing the photoconductor to a period for exposing a dot, is changed in the same document according to dot information on the document such as an edge signal. In the modulation of the optical intensity, the light emission onto the photoconductor is performed with a duty ratio which may be set for each dot. Image portions formed with different duty ratios may exist at the same time in a reproduced image. For example, an edge portion in a document is reproduced at the duty ratio of 100% while a non-edge portion is reproduced at the duty ratio less than 100%.
摘要:
In a digital full color copying machine, one pixel on a photoconductor is divided into four subdivided small pixels. Functions a-d are assigned to each subdivided small pixel. Functions a-d are linear functions with density data as a parameter. The slope of functions a-d becomes smaller in sequential order. Exposure data of the four subdivided small pixels is calculated according to the density data of a pixel and functions a-d to expose each subdivided small pixel. A peak can be established in the exposure amount distribution to form a deeper latent image. Accordingly, resolution and graininess of the halftone area are improved.
摘要:
A printer control unit carries out a predetermined calculation based on the amount of adhering toner detected by an AIDC sensor and the surface potential of a photoconductor detected by a V sensor to correct the light emission intensity of a light source to prepare light emission characteristic data for .gamma. correction to obtain an optimal image. A .gamma. correcting unit corrects an image signal output from an image signal processing unit using the calculated light emission characteristic data for .gamma. correction to control the light source to emit light based on the corrected data. More specifically, since the .gamma. correction data is obtained by calculation, optimal .gamma. correction can always be carried out without a memory of a large capacity.
摘要:
An image forming device capable of providing an image of excellent quality without unevenness of density. According to the image forming device, a controller measures light quantity for each light emitting element of the exposing device as to the pattern where only one of the light emitting elements is turned on, and as to the pattern where all the light emitting elements are turned on. Based on the data about the measured light quantity, a change rate in the light quantity distribution of the exposing device is calculated. Based on the data about the measured light quantity and the change rate in the light quantity distribution calculated, correction value for each of the light emitting elements of the exposing device is determined.
摘要:
A method of and apparatus for forming an image adapted to apply an error diffusion method to an input image data having N gradations so as to convert it into an output image data having M gradations, where M