Abstract: The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The image forming units are disposed facing towards the transfer belt device. The transfer belt device, at least in a portion in which the image forming units have been disposed, is arranged such that it is inclined with respect to the ground. Each of the image forming unit forms a desired image and sequentially transfers the formed image on the transfer member fed by the transfer belt device.

Abstract: The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The image forming units are disposed facing towards the transfer belt device. The transfer belt device, at least in a portion in which the image forming units have been disposed, is arranged such that it is inclined with respect to the ground. Each of the image forming unit forms a desired image and sequentially transfers the formed image on the transfer member fed by the transfer belt device.

Abstract: A mark pattern forming unit forms a mark pattern on a transfer belt, and a reflection type optical sensor detects the mark pattern. An interval difference acquiring unit acquires an interval difference that is a deviation of each mark from a reference position. A speed detector detects a moving speed v1 of the transfer belt in a period between formation of the mark pattern and the detection of the mark pattern, and a moving speed v2 during image formation. A speed difference calculating unit calculates a speed difference ?v=v1?v2, and a control unit controls a timing of forming an image based on the interval difference and the value of ?v so as to reduce position misalignment.

Abstract: The present invention relates to an electrophotographic color image forming apparatus using a tandem-drum development, an indirect image-transfer method, and a vertical sheet supply path. An intermediate image-transfer member is angled relative to a horizontal line such that a rear side of the intermediate image-transfer member away from a recording sheet is lifted and a front side of the intermediate image-transfer member closer to the recording sheet is lowered. Further, image creating mechanisms of the tandem-drum development are aligned and arranged in parallel to a moving image transfer bed of the intermediate image-transfer member, such that one of the image creating mechanisms firstly forming an image faces the rear side of the moving image transfer bed and another one of the image creating mechanisms lastly forming an image faces the front side.

Abstract: The present invention relates to an electrophotographic color image forming apparatus using a tandem-drum development, an indirect image-transfer method, and a vertical sheet supply path. An intermediate image-transfer member is angled relative to a horizontal line such that a rear side of the intermediate image-transfer member away from a recording sheet is lifted and a front side of the intermediate image-transfer member closer to the recording sheet is lowered. Further, image creating mechanisms of the tandem-drum development are aligned and arranged in parallel to a moving image transfer bed of the intermediate image-transfer member, such that one of the image creating mechanisms firstly forming an image faces the rear side of the moving image transfer bed and another one of the image creating mechanisms lastly forming an image faces the front side.

Abstract: The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The image forming units are disposed facing towards the transfer belt device. The transfer belt device, at least in a portion in which the image forming units have been disposed, is arranged such that it is inclined with respect to the ground. Each of the image forming unit forms a desired image and sequentially transfers the formed image on the transfer member fed by the transfer belt device.

Abstract: A method of color displacement detection for use in a color image forming apparatus sequentially forming image layers in different colors on a photosensitive member and overlaying the image layers on one after another into a color image on a transferring member. This method includes steps of forming, detecting, and calculating. The forming step forms a predetermined number of mark sets within one circumferential length surface of the transferring member. Each of the predetermined number of mark sets includes a predetermined number of different color marks arranged in a line in a moving direction of the transferring member. The detecting step detects the predetermined number of mark sets formed on the transfer member. The calculating step calculates mean values of displacement amounts of same color marks in different mark sets in the predetermined number of mark sets relative to respectively corresponding reference positions.

Abstract: The color image formation apparatus of the invention can include an image formation unit that is placed diagonally in relation to the vertical direction, a largest paper-feed tray that is placed below the image formation unit and feeds paper to image formation sections of the image formation unit, and a small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image formation apparatus of the invention can include an image formation unit that is placed diagonally in relation to the vertical direction, a largest paper-feed tray that is placed below the image formation unit and feeds paper to image formation sections of the image formation unit, and a small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image formation apparatus of the invention can include an image formation unit that is placed diagonally in relation to the vertical direction, a largest paper-feed tray that is placed below the image formation unit and feeds paper to image formation sections of the image formation unit, and a small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The present invention relates to an electrophotographic color image forming apparatus using a tandem-drum development, an indirect image-transfer method, and a vertical sheet supply path. An intermediate image-transfer member is angled relative to a horizontal line such that a rear side of the intermediate image-transfer member away from a recording sheet is lifted and a front side of the intermediate image-transfer member closer to the recording sheet is lowered. Further, image creating mechanisms of the tandem-drum development are aligned and arranged in parallel to a moving image transfer bed of the intermediate image-transfer member, such that one of the image creating mechanisms firstly forming an image faces the rear side of the moving image transfer bed and another one of the image creating mechanisms lastly forming an image faces the front side.

Abstract: A mark pattern forming unit forms a mark pattern on a transfer belt, and a reflection type optical sensor detects the mark pattern. An interval difference acquiring unit acquires an interval difference that is a deviation of each mark from a reference position. A speed detector detects a moving speed v1 of the transfer belt in a period between formation of the mark pattern and the detection of the mark pattern, and a moving speed v2 during image formation. A speed difference calculating unit calculates a speed difference &Dgr;v=v1−v2, and a control unit controls a timing of forming an image based on the interval difference and the value of &Dgr;v so as to reduce position misalignment.

Abstract: An image forming apparatus of the present invention includes image carriers arranged side by side in a preselected direction, developing means each for forming a toner image on one of the image carriers, a drive mechanism for driving in the preselected direction a member to which toner images are to be sequentially transferred from the image carriers one above the other, and image transferring devices each for transferring a toner image from one of the image carriers to the above member. At least during an image forming process, a slip condition is substantially the same throughout all image transfer positions where the image carriers face the member.

Abstract: The color image formation apparatus of the invention comprises: the image formation unit that is placed diagonally in relation to the vertical direction; the largest paper-feed tray that is placed below the image formation unit and feeds paper to the image formation sections of the image formation unit; and the small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image formation apparatus of the invention comprises: the image formation unit that is placed diagonally in relation to the vertical direction; the largest paper-feed tray that is placed below the image formation unit and feeds paper to the image formation sections of the image formation unit; and the small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image formation apparatus of the invention comprises: the image formation unit that is placed diagonally in relation to the vertical direction; the largest paper-feed tray that is placed below the image formation unit and feeds paper to the image formation sections of the image formation unit; and the small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image formation apparatus of the invention can include an image formation unit that is placed diagonally in relation to the vertical direction, a largest paper-feed tray that is placed below the image formation unit and feeds paper to image formation sections of the image formation unit, and a small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: A method of color displacement detection for use in a color image forming apparatus sequentially forming image layers in different colors on a photosensitive member and overlaying the image layers on one after another into a color image on a transferring member. This method includes steps of forming, detecting, and calculating. The forming step forms a predetermined number of mark sets within one circumferential length surface of the transferring member. Each of the predetermined number of mark sets includes a predetermined number of different color marks arranged in a line in a moving direction of the transferring member. The detecting step detects the predetermined number of mark sets formed on the transfer member. The calculating step calculates mean values of displacement amounts of same color marks in different mark sets in the predetermined number of mark sets relative to respectively corresponding reference positions.

Abstract: The color image formation apparatus of the invention comprises: the image formation unit that is placed diagonally in relation to the vertical direction; the largest paper-feed tray that is placed below the image formation unit and feeds paper to the image formation sections of the image formation unit; and the small-size paper-feed tray, placed below the image formation unit and above the largest paper-feed tray, which feeds paper to the image formation sections of the image formation unit.

Abstract: The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The image forming units are disposed facing towards the transfer belt device. The transfer belt device, at least in a portion in which the image forming units have been disposed, is arranged such that it is inclined with respect to the ground. Each of the image forming unit forms a desired image and sequentially transfers the formed image on the transfer member fed by the transfer belt device.