Abstract: An image forming apparatus includes a specific color image forming station for forming a black image and one or more non-specific color image forming stations for forming images of colors other than black, the photosensitive drum of the specific color image forming station is located vertically downward of the photosensitive drums of the non-specific color image forming stations, and the capacity of the black toner cartridge of the specific color image forming station is made larger than those of the toner cartridges of the non-specific color image forming stations. With this arrangement, the frequency of replacement of the black toner cartridge can be reduced without adversely affecting the size of an apparatus main body.

Abstract: The image forming apparatus includes a first placement member, a second placement member, a third placement member and a fourth placement member, which contact with a placement surface on which the image forming apparatus is placed, and which support the image forming apparatus, a side plate of the image forming apparatus, and a supporting section for supporting the image forming apparatus. The supporting section is supported by the third placement member and the fourth placement member, which are movable in a vertical direction of the image forming apparatus. This can prevent the deformation of the image forming apparatus without increasing the load on a bottom plate.

Abstract: An image forming apparatus includes a specific color image forming station for forming a black image and one or more non-specific color image forming stations for forming images of colors other than black, the photosensitive drum of the specific color image forming station is located vertically downward of the photosensitive drums of the non-specific color image forming stations, and the capacity of the black toner cartridge of the specific color image forming station is made larger than those of the toner cartridges of the non-specific color image forming stations. With this arrangement, the frequency of replacement of the black toner cartridge can be reduced without adversely affecting the size of an apparatus main body.

Abstract: The image forming apparatus includes a first placement member, a second placement member, a third placement member and a fourth placement member which contact with a placement surface for placing the image forming apparatus thereon, and which support the image forming apparatus, a side plate of the image forming apparatus, and supporting means as the supporting member for supporting the third placement member and the fourth placement member movably in a vertical direction of the image forming apparatus. This can prevent the deformation of the image forming apparatus without increasing the load on a bottom plate.

Abstract: An image forming apparatus includes a belt member, a driving roller arranged to support the belt member and to transmit a driving force to the belt member, a plurality of image forming units arranged to respectively form a plurality of color images on the belt member or on a recording material borne by the belt member in such a way as to have the plurality of color images superposed on top of one another, a measuring sensor for measuring a length of time required for the belt member to move a predetermined distance, and a control circuit for controlling, on the basis of the length of time measured by the measuring sensor, the timing of start of forming each of the plurality of color images by each of the plurality of image forming units on the belt member or on the recording material borne by the belt member.

Abstract: An image forming apparatus includes plural image forming units for respectively forming images of plural colors in a superposed manner on a recording material in a case of adjusting the relation position of the images of plural colors on a recording material. A first image forming unit among the plural image forming units forms a line of a first color on the recording material, while a second image forming unit forms a line of a second color on the recording material such as to cross the line of the first color at a non-perpendicular angle. An adjustment unit adjusts the relative positions of the images of plural colors on the recording material, based on input information.

Abstract: An image forming apparatus includes a plurality of image bearing members, an image forming device for forming images of plural colors on the plurality of image bearing members, a recording material conveying belt for bearing and conveying a recording material thereon, a drive roller for transmitting a driving force to the recording material conveying belt, the images of plural colors on the plurality of image bearing members formed by the image forming device being successively transferred to the recording material formed on the recording material conveying belt in superposed relationship with one another, and a control device for controlling the rotating speed of the drive roller on the basis of the thickness information of the recording material conveying belt in the direction of movement of the recording material conveying belt.

Abstract: A method of printing in which, when an image is divided to be printed into a plurality of lines, the feeding amount of a printing medium is equalized in each line for eliminating a feeding error of the printing medium to print a high-quality image. The image to be printed in a top line of the printing medium is formed into a printable image by ink ejection ports located at an upstream side with respect to a printing medium feeding direction of a print head, and a width of the image printed in the top line is an adjusting width for unifying the width of image printed in other lines to a specified width according to the print head.

Abstract: An image forming apparatus includes a plurality of recording heads arranged in parallel along a scanning direction perpendicular to a direction of transferring a recording medium to perform a recording movement for recording an image selected from a single-color image and a multicolor image in accordance with the image data. The recording heads record the multicolor image during a period of moving in one direction and record the single-color image during a period of moving in two opposite directions.

Abstract: A sheet thickness detecting device for detecting the thickness of a recording member precisely irrespective of accuracy of parts is disclosed. A state that a roller 1 of a pair of rollers 1, 2 is positioned at a predetermined angle of rotation, is detected by a flag 11 fixed to the axle of the roller 1 and a photosensor 12 for roller rotation angle detection. A signal from a photosensor 8 for roller pair axes distance detection is processed in accordance with a signal from the photosensor 12 to detect the thickness of a recording member P. In this device, the thickness of the recording member P is detected when the rollers 1, 2 are positioned at the predetermined angle of rotation. Thus, it can be detected accurately without being affected by eccentricities of the rollers 1, 2.

Abstract: In a serial page printer for printing an image line by line by scanning a printing head, even if a motor for driving a roller for conveying a printing medium is rotated by a predetermined amount, the printing medium is not conveyed by a predetermined amount depending on decentering of the roller, the position of the printing medium, and the like, resulting in a printing error. In order to prevent this, a predetermined position of the roller is brought into contact with each line of a printing medium. For this purpose, an apparatus of the present invention detects that the position of the printing medium and the state of the roller are in a predetermined state. Therefore, a line subjected to printing and the state of the roller have a predetermined relationship on any page, and the printing medium can be conveyed by a predetermined amount for each line by adjusting the rotational amount of the roller for each line in advance.

Abstract: An image forming apparatus comprises a plurality of different image forming units for recording with different methods. An ink jet recording unit is arranged on the upstream side of an electrophotography recording unit in a transporting path of a recording medium. Recording of the ink jet recording unit is performed prior to that of the electrophotography recording unit.

Abstract: An image forming apparatus comprises a plurality of different image forming units for recording with different methods. An ink jet recording unit is arranged on the upstream side of an electrophotography recording unit in a transporting path of a recording medium. Recording of the ink jet recording unit is performed prior to that of the electrophotography recording unit.

Abstract: A developing apparatus having a supporting frame for supporting plural developing units. The supporting frame is movable to present a selected one of the developing units to a development operating position. The supporting frame is provided with positioning members for positioning the developing units. The positioning members are fixed on the movable frame in the manner that the position of the positioning member is adjustable. Each of the developing units is faced to an image bearing member at the operating position without contact to the image bearing member.