Abstract: A discharge unit is disposed downstream of a principal transport path of a compound machine, and a shifter function is provided in this discharge unit. By shifting the paper passage position relative to a photosensitive drum when printing the front side and the paper passage position relative to the photosensitive drum when printing the back side, the region in which the surface electric potential of the photosensitive drum increases is diminished, and the region in which photographic fog is generated is made smaller. Thus, when printing the second and subsequent sheets, even when a slight amount of displacement of the transport position of the recording paper occurs, it is possible to suppress that recording paper making contact in the photographic fog region on the photosensitive drum, and defective printing can be prevented.

Abstract: A sheet delivery mechanism designed to discharge successive sheets to different delivery positions includes offset rollers, an offset unit, an offsetting force generator and an offset unit swinging mechanism. The offset rollers is rotatably supported by the offset unit to discharge each sheet in a sheet transport direction. The offsetting force generator produces a driving force for shifting the offset unit back and forth along a direction perpendicular to the sheet transport direction between a reference position and offset positions. The offset unit swinging mechanism swings the offset unit about an axis parallel to rotary shafts of the offset rollers in such a manner that a sheet output direction in which the offset rollers eject each sheet varies to a direction pointing away from a sheet delivery tray when the offset unit is shifted along the direction perpendicular to the sheet transport direction by the offsetting force generator.

Abstract: An electrophotographic image forming apparatus is provided with a developer collecting device which collects developer removed from an image bearing member and an intermediate transfer body by a cleaning section. The developer collecting device comprises a positioning frame for determining a mounting position of the image bearing member onto an image forming apparatus main body; a waste developer container detachably mounted on the positioning frame 4, for accommodating waste developer collected by the cleaning section; and an integrated container detection section for detecting whether or not the waste developer container is mounted on the positioning frame and whether or not the waste developer container is filled up with the waste developer.

Abstract: A transfer device has primary transfer rollers supported so as to be upwardly and downwardly movable within a path of movement and opposed to respective of photosensitive drums across a portion of an intermediate transfer belt. There are also provided a slide member for full-color image formation and a slide member for monochromatic image formation, which are capable of reciprocation in a horizontal direction. The transfer device includes roller lifting means each L-shaped and each having one end supporting an associated one of the transfer rollers for rotation and another end engaging an associated one of the slide members, and first and second coaxial rotating cams. The transfer device is capable of switching between three paths of movement of the intermediate transfer belt selectively by the first and second rotating cams rotating together.

Abstract: When handle region(s) of disengaging lever(s) is/are pulled in direction(s) tending to cause disengagement of engagement between access-controlling body or bodies and main body housing(s), respective action edge(s) of rotating region(s) may rotate about shaft(s) in direction(s) tending to cause disengagement of engagement. Upon rotating in direction(s) tending to cause disengagement of engagement, respective action edge(s) of rotating region(s) may press on and impel support plate(s) of main body housing(s). In accompaniment thereto, disengaging lever(s) may move upward, and respective downwardly directed engagement projection(s) of access-controlling body or bodies may be lifted up and extricated from respective upwardly directed engagement projection(s) of main body housing(s).

Abstract: An image forming apparatus includes a photoreceptor, a cleaning unit, an exposing unit, a developing unit, and a control section. On a circumferential surface thereof, the photoreceptor has an image area to have contact with a record medium in an image forming process, and a non-image area. The cleaning unit has a blade in contact with the image and non-image areas. The exposing unit forms an electrostatic latent image on the surface by irradiating the surface along a fast scanning direction with light modulated according to image data supplied by the control section. The data includes primary image data for modulating light to irradiate the image area with. The developing unit develops the latent image by applying developer to the surface. The control section performs an image addition processing in which secondary image data for modulating light to irradiate the non-image area with is added to the primary image data.

Abstract: A color image forming apparatus includes: process printing units each having a photoreceptor drum; a transfer belt to which toner images are transferred; a transfer roller for transferring, as a whole, the toner images on the transfer belt to recording paper; a cleaning unit for collecting the remaining developers that have been left over on the photoreceptor drums and the transfer belt, is constructed such that a positioning sub-frame which is set with a developer collecting container for storing the collected developers and positions the process printing units relative to the housing, on one side of the apparatus body is removably attached to the housing.

Abstract: An ozone exhaust system in an image forming apparatus having a multiple number of process printing units, includes: exhaust ducts for exhausting ozone arising in the process printing units. In the ozone exhaust system, the exhaust ducts are mainly constituted of process printing unit's side exhaust ducts provided respectively along multiple charger cases and a main exhaust duct to which the process printing unit's side exhaust ducts are connected, and the process printing unit's side exhaust ducts are constructed so that the air current that flows into the charger cases and the air current that flows from the process printing unit's side exhaust ducts into the main exhaust duct are directed in the same direction.

Abstract: A color image forming apparatus includes: a multiple number of process printing units, each having an photoreceptor drum for supporting a developer image formed with a developer corresponding to each color of color-separated image information; a transfer belt to which the developer images formed on the photoreceptor drums are transferred; and a transfer roller for transferring the transferred developer image to recording paper, and is constructed so that the transfer belt is formed of a material which makes it possible for the transfer belt to attenuate the voltage charged thereon by 1,000 V or greater while it moves from a position where secondary transfer is performed to a position where the initial primary transfer is performed.

Abstract: A waste toner collecting container which is used in a color image forming apparatus and can be removed from the machine and stores waste toner particles which have not been transferred to recording paper and have been collected, is constructed such that an air sealing member is disposed at the coupling between the waste toner collecting container and a conveying member for conveying the collected waste toner into the waste toner collecting container to prevent the waste toner from seeping out at the coupling when the waste toner is conveyed and to seal the collecting port so that no waste toner will spill out from the waste toner collecting container which has been removed for replacement after the waste toner collected and conveyed therein has reached the predetermined amount.

Abstract: A color image forming apparatus 1 includes: a multiple number of process printing units 20, each having an photoreceptor drum 21 for bearing a developer image formed with a toner corresponding to a different color of color-separated image information; a transfer belt 31 to which a multiple number of developer images are comprised in layers; and a transfer roller 36 for transferring the developer images that have been comprised in layers on transfer belt 31, all at once, to recording paper, wherein the multiple number of process printing units 20 are arranged along transfer belt 31, and is characterized in that among the developer images to be transferred from the photoreceptor drums 21 of multiple image forming units 20 onto transfer belt 31, the toner for the developer image of the color to be transferred first is specified to produce a base-layer of the color images of information.

Abstract: In an image forming apparatus a primary transfer is carried out such that toner images on a plurality of photoreceptors are transferred and laminated onto an intermediate transfer member, and a recording paper and the intermediate transfer member are sandwiched between a secondary transfer roller disposed so as to be in contact with the intermediate transfer member and a secondary transfer counter roller disposed opposite to the secondary transfer roller, to carry out a secondary transfer that the toner images on the intermediate transfer member are transferred onto the recording paper. At the time, an electric field is applied to the recording paper, and further the secondary transfer counter roller is switched by a switch between grounded state and floating state so that a potential difference between the intermediate transfer member and the secondary transfer roller can be adjusted.

Abstract: A transfer device includes: a discharge type transfer element for transferring the developer to a sheet by discharging electric charge to a static latent image support through the sheet so as to form an image of an original thereon; and a transfer casing accommodating the transfer element, wherein the side on the sheet's entrance side is formed of an electrically insulating element, and is constructed such that the transfer element and transfer casing are arranged so as to be offset to the upstream side with respect to the rotational direction of the static latent image support, along the outer peripheral surface thereof and so that the upper end of the insulating element blocks up into the paper feed path, and the insulating element is adapted to be bent toward the sheet feed direction by virtue of an elastic member.

Abstract: An image forming apparatus is constituted so as to be equipped with transfer apparatus(es) having transfer roller(s) electrostatically transferring development image(s) from photosensitive drum(s) to transfer medium/media, and so as to be provided with transfer medium guide means disposed downstream in transfer medium transport path(s) from location(s) at which photosensitive drum(s) oppose transfer roller(s), and such that transfer medium guide location(s) of transfer medium guide means is/are variable.

Abstract: A transfer apparatus and an image forming apparatus are disclosed, in which a plurality of photosensitive drums corresponding to the respective colors are arranged along the outer peripheral surface of a transfer belt and a plurality of intermediate transfer rollers for applying a transfer field to the photosensitive drums are arranged offset downstream side from each of the photosensitive drums, respectively. In addition to that, the process, the intermediate transfer rollers are arranged in such positions that each of the nip width are increased progressively downstream side, respectively and each of the nip pressure are decreased progressively downstream side, respectively.

Abstract: A transfer apparatus and an image forming apparatus capable of transferring an image satisfactorily using developing agent are disclosed. A transfer system includes photosensitive drums corresponding to the respective colors arranged along the outer peripheral surface of a transfer belt and intermediate transfer rollers arranged offset downstream side from the respective photosensitive drums for applying a transfer field to the respective photosensitive drums. The transfer belt is configured of a material such as polyimide or polycarbonate in which a surge current of not less than a specified value flows immediately after application of a transfer voltage.

Abstract: A cleaning system includes a rotating member and a cleaning blade which is forced against a curved outer surface of the rotating member to scrape off matter to be removed (toner) which is present along the outer surface of the rotating member. The cleaning blade has greater hardness than the outer surface of the rotating member.

Abstract: A rotation speed of a heating roller 39a and a pressure roller 39b is variably controlled by a CPU 542 based on a sheet size to be printed, a direction the sheet is to be passed, and a number of sheets to be printed. Specifically, variable control of the rotation speeds of the heating roller 39a and the pressure roller 39b by the CPU 542 is based on an occurrence of a pass-through area 39b1 and a non-pass-though area 39b2 by a sheet of recording paper with respect to a roller lengthwise direction (axial direction) of a position at which the sheet of recording paper passes between the heating roller 39a and the pressure roller 39b, and controlled based on a thermal expansion coefficient of a roller diameter of the non-pass-though area 39b2 of the pressure roller 39b.

Abstract: A transfer device has primary transfer rollers supported so as to be upwardly and downwardly movable within a path of movement and opposed to respective of photosensitive drums across a portion of an intermediate transfer belt. There are also provided a slide member for full-color image formation and a slide member for monochromatic image formation, which are capable of reciprocation in a horizontal direction. The transfer device includes roller lifting means each L-shaped and each having one end supporting an associated one of the transfer rollers for rotation and another end engaging an associated one of the slide members, and first and second coaxial rotating cams. The transfer device is capable of switching between three paths of movement of the intermediate transfer belt selectively by the first and second rotating cams rotating together.

Abstract: An image forming apparatus includes a pair of optical sensing devices for monochrome image forming and full-color image forming which are disposed at the rear of the image forming apparatus and a pair of generally L-shaped light shielding members for monochrome image forming and full-color image forming which are mounted swingably on a rear side of an image transfer unit with one end of each light shielding member attached to one of two sliding members. When each of the sliding members moves back and forth, the light shielding member for monochrome image forming or full-color image forming, whichever applicable, swings and the relevant optical sensing device detects the other end of the light shielding member.