Abstract: In the image processing apparatus, image data is divided into large blocks of a prescribed size and the large blocks are subdivided into small blocks by the dividing unit. The number of isolated points in each large block is then calculated by the large block isolated point calculation unit, and the number of isolated points in each small block is then calculated by the small block isolated point calculation units. It is then determined by the halftone-dot region determination unit whether or not the large block is a halftone-dot region. This determination considers both the number of isolated points in the large block and the number of isolated points in each small block.

Abstract: A high voltage semiconductor device includes a semiconductor substrate, a p type base region in a first main surface, an n+ type emitter region in the p type base region, an n+ type cathode region adjacent to an end surface of the semiconductor substrate and not penetrating the semiconductor substrate, a p+ type collector region in a second main surface, a first main electrode, a second main electrode, a third main electrode, and a connection portion connecting the second main electrode and the third main electrode. A resistance between the p type base region and the n+ type cathode region is greater than a resistance between the p type base region and the p+ type collector region. In the high voltage semiconductor device in which an IGBT and a free wheel diode are formed in a single semiconductor substrate, occurrence of a snap-back phenomenon is suppressed.

Abstract: A high voltage semiconductor device includes a semiconductor substrate, a p type base region in a first main surface, an n+ type emitter region in the p type base region, an n+ type cathode region adjacent to an end surface of the semiconductor substrate and not penetrating the semiconductor substrate, a p+ type collector region in a second main surface, a first main electrode, a second main electrode, a third main electrode, and a connection portion connecting the second main electrode and the third main electrode. A resistance between the p type base region and the n+ type cathode region is greater than a resistance between the p type base region and the p+ type collector region. In the high voltage semiconductor device in which an IGBT and a free wheel diode are formed in a single semiconductor substrate, occurrence of a snap-back phenomenon is suppressed.

Abstract: A high voltage semiconductor device includes a semiconductor substrate, a p type base region in a first main surface, an n+ type emitter region in the p type base region, an n+ type cathode region adjacent to an end surface of the semiconductor substrate and not penetrating the semiconductor substrate, a p+ type collector region in a second main surface, a first main electrode, a second main electrode, a third main electrode, and a connection portion connecting the second main electrode and the third main electrode. A resistance between the p type base region and the n+ type cathode region is greater than a resistance between the p type base region and the p+ type collector region. In the high voltage semiconductor device in which an IGBT and a free wheel diode are formed in a single semiconductor substrate, occurrence of a snap-back phenomenon is suppressed.

Abstract: A semiconductor device includes a transistor, a first diode, and a second diode. A collector of the transistor and a cathode of the first diode are electrically connected. The collector of the transistor and a cathode of the second diode are electrically connected, and an emitter of the transistor and an anode of the second diode are electrically connected. The first diode and the second diode are formed in an identical substrate. Thereby, the semiconductor device can be produced in a smaller size and in less steps.

Abstract: A semiconductor device includes a transistor, a first diode, and a second diode. A collector of the transistor and a cathode of the first diode are electrically connected. The collector of the transistor and a cathode of the second diode are electrically connected, and an emitter of the transistor and an anode of the second diode are electrically connected. The first diode and the second diode are formed in an identical substrate. Thereby, the semiconductor device can be produced in a smaller size and in less steps.

Abstract: The inventive image processing apparatus takes steps of 1) dividing an image to be processed into numerals of blocks; 2) determining whether a block is a color block or not; 3) determining whether the image is a color image or not based on the rate of color blocks to the entire blocks. Thereby, valid color pixel rate can be obtained at blocks belonging to a color region even though an image is almost monochrome but partially colored. Accordingly, the inventive image processing apparatus can appropriately determine whether the image is a color image or not.

Abstract: It is objected to provide an image processing apparatus achieving decrease of memory volume to be used, simplified print process, and enhancement of productivity. Firstly, a plurality of image data are recorded in memories provided for respective colors. Based on the image data or mode selection by a user, it is determined that whether a multi-color image or a monochrome image is to be outputted. Next, memories 302 of respective colors transmit image data of respective colors to a computing unit 304 in accordance with readout-timing signals from a timing selector 305. In case a multi-color image is to be outputted, the timing selector 305 transmits readout-timing signals of respective colors taking time difference length of which is predetermined for each color. In case a monochrome image is to be outputted, the timing selector 305 transmits readout-timing signals of respective color simultaneously.

Abstract: An image forming apparatus using an exposure unit of a solid-scanning type such as an LED head, reads out linear distortion correction data of an LED unit, then, calculates an amount of correcting color deviation based on the read-out data, and after that, carries out address control for color deviation correction memory. Based on this control, the apparatus creates a reference resist patterns, calculates an amount of correcting the color deviation, and writes the calculated amount in the color deviation correction memory. After that, the apparatus reads out the linear distortion correction data, and adds the amount of correcting the color deviation that is determined by sensors, and the amount of the color correction based on the linear distortion correction data, thereby carries out address controls for the color deviation correction memory.

Abstract: The present invention relates to an image processor provided in apparatuses such as digital copiers and printers, and that distinguishes between a character edge region and a continuous tone region of an original image and switches the tone reproduction processing between the regions.

Abstract: The inventive image processing apparatus takes steps of 1) dividing an image to be processed into numerals of blocks; 2) determining whether a block is a color block or not; 3) determining whether the image is a color image or not based on the rate of color blocks to the entire blocks. Thereby, valid color pixel rate can be obtained at blocks belonging to a color region even though an image is almost monochrome but partially colored. Accordingly, the inventive image processing apparatus can appropriately determine whether the image is a color image or not.

Abstract: There is provided an image processing apparatus and an image processing method capable of conducting different manners of resolution conversion processing depending on scanning direction. An image processing apparatus 1 includes: a sub-scanning-directional first resolution converting section 4 for enhancing resolution of input image data in a sub-scanning direction; a sub-scanning-directional second resolution converting section 5; a main-scanning-directional first resolution converting section 14 for enhancing resolution of input image data in a main-scanning direction; and a main-scanning-directional second resolution converting section 15. The structure such as above enables the image processing apparatus 1 to conduct resolution conversion processing in sub-scanning direction and main-scanning direction independently, thereby to obtain a high-quality output image.

Abstract: The inventive image processing apparatus takes steps of 1) dividing an image to be processed into numerals of blocks; 2) determining whether a block is a color block or not; 3) determining whether the image is a color image or not based on the rate of color blocks to the entire blocks. Thereby, valid color pixel rate can be obtained at blocks belonging to a color region even though an image is almost monochrome but partially colored. Accordingly, the inventive image processing apparatus can appropriately determine whether the image is a color image or not.

Abstract: In an image processor which converts color image data to image data of cyan, magenta, yellow and black necessary for forming an image, a black character edge is discriminated in R, G, B image data. The edge component in a black character area is deleted by narrowing on image data of cyan, magenta and yellow. Further, in a black character area, K data is replaced with maximum density data in the R, G, B data, and edge emphasis is performed on the substituted data. Then, reproducibility of a thin line portion in a character is improved largely.

Abstract: The inventive image processing apparatus takes steps of 1) dividing an image to be processed into numerals of blocks; 2) determining whether a block is a color block or not; 3) determining whether the image is a color image or not based on the rate of color blocks to the entire blocks. Thereby, valid color pixel rate can be obtained at blocks belonging to a color region even though an image is almost monochrome but partially colored. Accordingly, the inventive image processing apparatus can appropriately determine whether the image is a color image or not.

Abstract: Image distortion is corrected in a color printer wherein print units for a plurality of colors are aligned to form a color image by superposing images formed by the print units. A quantity of image distortion is detected, and correction data of main scan address and subscan address are calculated and stored according to the detected image distortion for each main scan address. When input color image data are corrected, printing position is corrected in combination of address change with density interpolation. When the correction data exceeds the maximum correction range, the correction data are replaced by the maximum in the correction range for distortion correction. Further, in the image data correction, after the image data are converted to data having a smaller number of gradation levels, the data are delayed according to the serial arrangement of the print units. Then, the delayed data are converted again for printing.

Abstract: 1,800 dpi binary image data is divided into 3-bit data groups or 2-bit data groups, and is input from an input unit 11 to a tone setting unit 12 and a print position controller 13. Each group of 3-bit image data is converted into 8-bit tone data and 2-bit attribute data by the tone setting unit 12 and the print position controller 13, respectively, and both sets of post-conversion data are input to a pulse width modulation unit 15 at the same time. Because all 3-bit data is handled at the same time, the input and output operation clock signals can stay the same as for a 600 dpi resolution.

Abstract: The inventive image processing apparatus takes steps of 1) dividing an image to be processed into numerals of blocks; 2) determining whether a block is a color block or not; 3) determining whether the image is a color image or not based on the rate of color blocks to the entire blocks. Thereby, valid color pixel rate can be obtained at blocks belonging to a color region even though an image is almost monochrome but partially colored. Accordingly, the inventive image processing apparatus can appropriately determine whether the image is a color image or not.

Abstract: In an image processor on multi-level image data, an edge direction of a target pixel is discriminated from differences in density level between the target pixel and adjacent pixels thereof. A pixel is divided into a plurality of sub-pixels, and the image is formed in the unit of sub-pixels. The density level is set for each of the sub-pixels in the target pixel in accordance with the discrimination on the edge direction of the target pixel so that the center of gravity in density is changed in the target level. Then a character edge portion is reproduced more smoothly.

Abstract: An image processor performs multilevel error diffusion processing and is provided with: a quantizing unit that quantizes pixel data constituting image information based on output values distributed at predetermined tone differences; an error detecting unit that detects a quantization error of the pixel data; a peripheral error calculating unit that integrates the quantization error of the pixel data detected by the error detecting unit with respect to a quantization error of peripheral pixel data; and an error superimposing unit that adds the integration error calculated by the peripheral error calculating unit to the pixel data input next. The image processor is further provided with: a random noise generating unit that generates random noise in accordance with the tone level of the input pixel data; and a noise superimposing unit that superimposes the random noise generated by the random noise generating unit on the pixel data.