Abstract: A plurality of LED circuits are each configured having white LEDs serially connected therein, and the white LEDs are arranged in alternate main scanning direction positions for each of the LED circuits. When any of these LED circuits has failed, an output light power of white LEDs of LED circuits that have not failed is increased by a light power control section, thereby compensating an extinguished amount of the failed LED circuit.

Abstract: Acquiring image data for each color component by guiding the reflected light from a read position on a contact glass, to a line sensor for each color component, detecting a provisional foreign matter region in one image data, determining a first condition on the basis of the number of pixels constituting the provisional foreign matter region, determining a second condition on the basis of the average value of the density values of all of the pixels within the provisional foreign matter region when the first condition is satisfied, and determining whether or not foreign matter is present at a read position corresponding to the one color component when the second condition is satisfied on the basis of the density value of the pixel corresponding to the provisional foreign matter region in one other image data and the fourth reference value that has been set in advance.

Abstract: The present disclosure relates to an image scanner and an image forming apparatus equipped with the image scanner, and more particularly to a technique of detecting that dew condensation occurs on a transparent member for placing a document thereon.

Abstract: An image forming apparatus, including: a fixing device having: a first heat generator for generating heat for a fixing processing, the first heat generator using electric power supplied by a commercial power source; and a second heat generator for generating heat for the fixing processing, the second heat generator using electric power supplied by the auxiliary power source device; a heat generation controller for allowing the first heat generator and the second heat generator to generate heat; a sheet jam detector for detecting a sheet jam of a recording sheet which occurs in the image forming section having the fixing device and a conveyance path of a recording sheet; and a charge controller for allowing charging of the auxiliary power source device to start when the sheet jam detector detects a sheet jam, and the charged capacity detector detects no full charge of the auxiliary power source device.

Abstract: A plurality of LED circuits are each configured having white LEDs serially connected therein, and the white LEDs are arranged in alternate main scanning direction positions for each of the LED circuits. When any of these LED circuits has failed, an output light power of white LEDs of LED circuits that have not failed is increased by a light power control section, thereby compensating an extinguished amount of the failed LED circuit.

Abstract: A fixing device comprises a heated member formed into a hollow, cylindrical shape, said heated member including a nonmagnetic portion having a particular length along an axial direction of said heated member, a magnetic flux generator for generating magnetic flux exerted on said heated member, a first magnetic core disposed face to face with said magnetic flux generator with said heated member positioned between said first magnetic core and said magnetic flux generator to form a magnetic circuit which is routed to come out of said magnetic flux generator, pass through said heated member and return to said magnetic flux generator, and a shifting mechanism for varying the length of an area of said heated member along the axial direction thereof where the nonmagnetic portion of said heated member and said first magnetic core face each other.

Abstract: An object of the present invention is to produce an image scanning apparatus for preventing occurrence of a black line in the scanning of a sheet of document. A light source 23 is moved between positions A and B when a sheet of a document is scanned while being transported. Accordingly, a scanning position is moved in a sub-scanning direction. Thus, movement of the scanning position makes it possible to prevent or to inhibit the occurrence of a black line on the scanned image.

Abstract: An image scanning device includes a white reference board 104 with a uniform white color, an irradiation device 601, an image sensor 207, and a determination device 602. The irradiation device 601 includes a light source unit to irradiate a reflection side of the white reference board 104 from only one oblique direction. The image sensor 207 is configured to detect reflected light from the white reference board 104. The determination device 602 is configured to determine if an attached substance exists on the reflection side of the white reference board 104 based on the reflected light detected by the image sensor 207.

Abstract: An image forming apparatus, including: a fixing device having: a first heat generator for generating heat for a fixing processing, the first heat generator using electric power supplied by a commercial power source; and a second heat generator for generating heat for the fixing processing, the second heat generator using electric power supplied by the auxiliary power source device; a heat generation controller for allowing the first heat generator and the second heat generator to generate heat; a sheet jam detector for detecting a sheet jam of a recording sheet which occurs in the image forming section having the fixing device and a conveyance path of a recording sheet; and a charge controller for allowing charging of the auxiliary power source device to start when the sheet jam detector detects a sheet jam, and the charged capacity detector detects no full charge of the auxiliary power source device.

Abstract: The present invention relates to an image data transfer controller. In the present invention, transfer processing for acquiring a right to control a bus and performing DMA transfer of image data corresponding to a set number of data to be continuously transferred and bus release processing for releasing the acquired right to control a bus during a set bus release period are repeatedly performed until a predetermined number of image data are transferred. The set value of the number of data to be continuously transferred and the set value of the bus release period are changed on the basis of the state of a request to use the bus.

Abstract: The present invention provides a matrix address generator for generating horizontal and vertical addresses in various patterns in the case where a memory table matrix provided in gradation data storage means is specified by the horizontal and vertical addresses. The matrix address generator comprises a dot counting portion, a line counting portion, an address exchanging portion, a boundary exchanging portion, matrix boundary counting portions, and adding portions. Addresses counted by the dot counting portion are exchanged by the address exchanging portion if necessary. The addresses and adding addresses counted by the matrix boundary counting portion are added together so that addresses having various patterns can be obtained.

Abstract: A basic clock generated from a crystal oscillator is delayed by a constant time in each of a plurality of delay elements connected in series. Consequently, internal clocks which differ in phase by a predetermined amount are outputted from the delay elements. Output signals of the delay elements are inputted to a clock selector. The clock selector selects any one of the internal clocks on the basis of a beam detection signal indicating the timing of the scanning of a photoreceptor by a laser beam to output the same as a video clock. The clock selector selects any one internal clock whose phase difference from the beam detection signal is closest to a predetermined phase difference out of the internal clocks, the phase difference from the beam detection signal meaning the time difference between the time when the beam detection signal has a predetermined phase angle and the time when the internal clock has a predetermined phase angle.

Abstract: A memory control device for controlling writing and reading data in and from a line memory made up of a plurality of FIFO memories. Writing clocks are circularly applied to the plurality of FIFO memories of the line memory. Also, reading clocks are circularly applied to the plurality of FIFO memories. Thus, although data written in the FIFO memories are discrete, data circularly read from the plurality of FIFO memories are sequential in such order as they are written in the line memory.

Abstract: A laser beam controller comprises a basic pulse signal generating circuit, a delay circuit, a delay control circuit, a pulse generating circuit and a laser beam generator. The basic pulse signal generating circuit generates periodically occurring basic pulse signal. The delay circuit delays the basic pulse signal. The delay control circuit controls the delay time of the basic pulse in the delay circuit according to image data. The pulse generating circuit generates an output pulse having a width corresponding to the delay time of the basic pulse signal. The laser beam generator generates a laser beam for a duration corresponding to the width of the output pulse by said pulse generating circuit. According to the controller, any desired gradation of a pixel of the image is desirably produced.