Ricoh Company, Ltd.

Hodogaya Chemical Co., Ltd.

Takehiro Nakajima

Katsumi Abe

Makoto Koike

Atsushi Takesue

Shinya Nagai

An image forming apparatus includes: a scanner to read each of a first output product serving as a model and a second output product output from the image forming apparatus; a memory that stores a color conversion lookup table to be used when color conversion is performed from a RGB color system into a CMYK color system; and circuitry to correct the color conversion lookup table based on a number of pixels and an amount of change per hue, using read information on the first output product, and re-correct the corrected color conversion lookup table, using read information on the second output product.

Image forming apparatus, image forming method, and non-transitory recording medium

An image forming device includes a density correction unit that corrects density based on a density detection value of the density correction pattern; a first density correction pattern generating unit that generates a first density correction pattern having low resolution; and a second density correction pattern generating unit that generates a second density correction pattern having high resolution. When a first density detection value of the first density correction pattern is greater than a predetermined threshold value, the density correction unit corrects the density by determining a density correction reflection rate, based on the first density detection value. When the first density detection value is less than or equal to the predetermined threshold value, the density correction unit corrects the density by determining the density correction reflection rate, based on a second density detection value of the second density correction pattern.

Image forming device, density correction method, and non-transitory computer readable storage medium storing program

An image forming apparatus having density correction characteristic data and a section to execute density conversion on input image data includes a section to generate detecting patterns with multiple area ratios, a section to create images of the patterns on an image bearing member, a section to detect the images of the patterns created on the image bearing member, a section to hold detected values corresponding to the images of the patterns detected from the image bearing member, a section to obtain fixed values or previously detected values as target values for correction, and correction coefficients, a section to calculate a correction characteristic corresponding to the detecting patterns from the obtained target values, the detected values, and correction coefficients, and a section to synthesize new density correction characteristic data from the density correction characteristic data and the correction characteristic corresponding to the patterns.

Image forming apparatus and density correction method

An object of the present invention is to provide an electrophotographic photosensitive body having improved electrophotographic characteristics such as sensitivity and residual potential and also having excellent durability. The present invention provides an electrophotographic photosensitive body having a layer containing at least one specific p-terphenyl compound and at least one polycarbonate resin represented by the general formula (I): in a mass ratio of the p-terphenyl compound to the polycarbonate resin within the range of 2:8 to 7:3.

Electrophotographic photosensitive body

An image forming apparatus including an attribute-value-information holding unit that holds an attribute-value table showing correspondence between a type of gradation processing and a fixing-temperature control attribute value; an image-formation-attribute processing unit that determines a type of gradation processing and a corresponding fixing-temperature control attribute value on the basis of contents of a print instruction and the attribute-value table; a gradation processing unit that performs gradation processing in accordance with the type of gradation processing determined by the image-formation-attribute processing unit; and a fixing-temperature control unit that controls fixing temperature in formation of a print image according to the fixing-temperature control attribute value determined by the image-formation-attribute processing unit.

Image forming apparatus, image forming method, and program

An object of the invention is to provide a method of making a p-terphenyl compound mixture which includes two symmetric p-terphenyl compounds respectively represented by formula (1) and formula (2) and an asymmetric p-terphenyl compound represented by formula (3) 

p-Terphenyl compound mixture and electrophotographic photoreceptors made by using the same

An image processing apparatus includes a plurality of color conversion tables for color-separation-limited printing. Using a color conversion table for color-separation-limited printing, a piece of input color information corresponding to chromatic color within a specified applying hue range for a specified specific color is converted into a piece of output color information corresponding to color having hue of the specific color, and a piece of the input color information corresponding to color outside of the applying hue range is converted into a piece of the output color information corresponding to gray color. Each of the color conversion tables for color-separation-limited printing is configured such that color values corresponding to saturation and lightness of the output color information are reduced at least in gradation from a maximum saturation part to a low-lightness part.

Image processing apparatus and color conversion table generating method

An object of the invention is to provide: a p-terphenyl compound mixture useful as a charge-transporting agent which has improved solubility in organic solvents to thereby diminish a cracking phenomenon, which poses problems concerning photoreceptor characteristics, and can realize an electrophotographic photoreceptor having high sensitivity and high durability; and an electrophotographic photoreceptor employing the compound mixture. The invention relates to: a p-terphenyl compound mixture which includes two symmetric p-terphenyl compounds respectively represented by the following general formula (1) and general formula (2) and an asymmetric p-terphenyl compound represented by the following general formula (3) which has both a group of substituents of the compound represented by general formula (1) and a group of substituents of the compound represented by general formula (2); and an electrophotographic photoreceptor containing the compound mixture. 

P-terphenyl compound mixture and electrophotographic photoreceptors made by using the same

An object of the present invention is to provide an electrophotographic photosensitive body which is not impaired in electrophotographic characteristics such as charged potential and residual potential, and which is also excellent in repeating stability. The present invention provides an electrophotographic photosensitive body including a conductive support having thereon a layer containing a specific p-terphenyl compound and at least one additive.

A feature amount converting unit performs a color conversion of an input data. A history storage unit stores history information about a measurement of a color chart including conversion values of measured values of the color chart. An arithmetic unit compares the history information with new input information for measurement of the color chart, and determines the number of color patches based on a result of the comparison. A profile updating unit updates a printer profile based on a determined color chart data, and stores the printer profile in the history storage unit.

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Tokyo, Japan

Takehiro Nakajima