Abstract: An image forming apparatus is provided with a latent image carrier for holding an electrostatic latent image, and an intermediate transfer member for temporally holding an image formed by visualizing the electrostatic latent image formed on the latent image carrier. The image forming apparatus performs image formation by superimposing a plurality of images on the intermediate transfer member so as to form a superimposing image, and transferring the superimposing image on a recording medium. The intermediate transfer member has a latent image holding property for holding the electrostatic latent image. An image formed by visualizing an electrostatic latent image formed on the intermediate transfer member is superimposed with the electrostatic latent image formed on the latent image carrier.

Abstract: A timer clocks and accumulates time periods during each of which a recording sheet is transported or transfer bias is applied as transfer execution periods. When the accumulated value reaches a predetermined value, the timer outputs a time-up signal to a CPU and then clears the accumulated value. The CPU executes a cleaning operation at the time the time-up signal is inputted from the timer. In the cleaning operation, the CPU causes a high-voltage power source to apply cleaning bias to a transfer electrode roller while causing a high-voltage power source to apply delivery bias to an auxiliary cleaning roller, in order to return toner attracted to the auxiliary cleaning roller to a photosensitive drum via a transfer belt.

Abstract: A junction/disjunction unit of a multicolored image forming apparatus joints/disjoints a transfer material holder with/from an image holder, to switch over between a monochromatic image forming mode which uses a specific image forming unit and a multicolored image forming mode which uses a plurality of image forming units. For switching the image forming mode, a driving unit for driving the junction/disjunction unit also drives an auger provided for conveying toner, which has been recovered by a transfer material holder cleaning unit for recovering toner remaining on the transfer material holder, into a recovery container. Accordingly, a driving force outputted from the driving unit can be effectively utilized, and thereby good cost performance can be realized.

Abstract: To provide a simply-arranged detaching/attaching mechanism and image forming device which allow a transfer supporter device (contacting member) to be detached/attached through a space formed by opening an outer covering, the present invention includes photosensitive drums, detachable/attachable transfer belt unit, and rail members supporting a transfer belt unit. Each of the rail members includes a rail groove for guiding the transfer belt unit, notch and positioning hole for determining the position of the transfer belt unit when the belt is in contact with the photosensitive drums, and notch and convex section for determining the position of the transfer belt unit when the belt is detached from the photosensitive drums. The support of the transfer belt unit with respect to the main body of the image forming device, which is performed by the rail members, is released in response to the action of opening the side cover, so that the transfer belt unit is caused to be in a free state.

Abstract: A plurality of photosensitive drums are disposed in a sheet transport direction so as to be in contact with a transfer belt and a transfer voltage for transferring toner images on the photosensitive drums onto a sheet transported by the transfer belt is applied thereto. A sensor for sensing a temperature or humidity in the working atmosphere of the image forming apparatus is provided; when a jam occurs, sheet transportation is ceased at a first stage to thereby enable the sheet in the jam to be removed; at a second stage subsequent thereto, transportation of the sheet is restarted; and a transport distance of the sheet is controlled based on a printing ratio of an image formed on the sheet.

Abstract: An image forming apparatus transfers a toner image formed on a photoconductor drum onto a sheet-like recording member while the sheet-like recording member is transported and attracted to a transfer belt, and comprises a jam handling control unit for detecting a transport fault of the sheet-like recording member, and for stopping the transport operation when the transport fault is detected. When the transport fault is detected in a section other than a fixing section, the jam handling control unit first causes the transport operation of the fixing section, and thereafter causes the transfer belt and the transport operation on the upstream side thereof to stop, and any sheet-like recording member remaining on the transfer belt so that the transport mechanism on the upstream side thereof is transported and stopped at the position spanning between the area of the fixing section and the area of the transfer belt.

Abstract: A tandem-type image forming apparatus for forming a multi-coor image on a sheet transported by an endless transfer/transport belt, by sequentially laying on the sheet images developed in respective image forming stations. The apparatus includes: transfer rollers, each in contact through the transfer/transport belt with an image carrier provided in each image forming station; and a voltage applying device for applying a non-transfer bias voltage to only the transfer rollers that are in contact with the image carriers when a transfer process is not performed, the non-transfer bias voltage having the same polarity as a transfer bias voltage and being lower than the transfer bias voltage.

Abstract: A plurality of photosensitive drums are disposed in a sheet transport direction so as to be in contact with a transfer belt and a transfer voltage for transferring toner images on the photosensitive drums onto a sheet transported by the transfer belt is applied thereto. A sensor for sensing a temperature or humidity in the working atmosphere of the image forming apparatus is provided; when a jam occurs, sheet transportation is ceased at a first stage to thereby enable the sheet in the jam to be removed; at a second stage subsequent thereto, transportation of the sheet is restarted; and the transfer voltage applied onto the transfer belt is controlled based on a measurement result of the sensor.

Abstract: A plurality of photosensitive drums are disposed in a sheet transport direction so as to be in contact with a transfer belt and a transfer voltage for transferring toner images on the photosensitive drums onto a sheet transported by the transfer belt is applied thereto. A sensor for sensing a temperature or humidity in the working atmosphere of the image forming apparatus is provided; when a jam occurs, sheet transportation is ceased at a first stage to thereby enable the sheet in the jam to be removed; at a second stage subsequent thereto, transportation of the sheet is restarted; and a transport distance of the sheet is controlled based on a printing ratio of an image formed on the sheet.

Abstract: An image forming apparatus transfers a toner image formed on a photoconductor drum onto a sheet-like recording member while the sheet-like recording member is transported and attracted to a transfer belt, and comprises a jam handling control unit for detecting a transport fault of the sheet-like recording member, and for stopping the transport operation when the transport fault is detected. When the transport fault is detected in a section other than a fixing section, the jam handling control unit first causes the transport operation of the fixing section, and thereafter causes the transfer belt and the transport operation on the upstream side thereof to stop, and any sheet-like recording member remaining on the transfer belt so that the transport mechanism on the upstream side thereof is transported and stopped at the position spanning between the area of the fixing section and the area of the transfer belt.

Abstract: A transfer unit 5, which has transfer members 51a corresponding to a plurality of image carriers arranged in a sheet transporting direction, for transferring images carried on the image carriers, has rotary fulcrums 50 in the vicinity of an extension of the axis of a transfer member 51a on an upstream side end portion or on an downstream side end portion in the sheet transporting direction so as to be approximately parallel to the axis, and can be rotated on the rotary fulcrums 50 in directions of moving to and from the image carriers. With this image forming apparatus, it is possible to keep stable orientation of the transfer unit while the apparatus is in operation, thereby realizing stable contact/separation movement of the transfer unit.

Abstract: A junction/disjunction unit 38 of the multicolored image forming apparatus joints/disjoints a transfer material holder with/from an image holder, to switch over between a monochromatic image forming mode which uses a specific image forming unit and a multicolored image forming mode which uses a plurality of image forming units. For switching the image forming mode, a driving unit 39 for driving the junction/disjunction unit 38 also drives an auger 37 provided for conveying toner, which has been recovered by a transfer material holder cleaning unit for recovering toner remaining on the transfer material holder, into a recovery container 36. Accordingly, a driving force outputted from the driving unit can be effectively utilized, and thereby good cost performance can be realized.

Abstract: An image forming apparatus transfers a toner image formed on a photoconductor drum onto a sheet-like recording member while the sheet-like recording member is transported and attracted to a transfer belt, and comprises a jam handling control unit for detecting a transport fault of the sheet-like recording member, and for stopping the transport operation when the transport fault is detected. When the transport fault is detected in a section other than a fixing section, the jam handling control unit first causes the transport operation of the fixing section, and thereafter causes the transfer belt and the transport operation on the upstream side thereof to stop, and any sheet-like recording member remaining on the transfer belt so that the transport mechanism on the upstream side thereof is transported and stopped at the position spanning between the area of the fixing section and the area of the transfer belt.

Abstract: The present invention includes: image carriers provided parallel to each other in a transfer area where toner images are transferred to a transfer medium; and transfer rollers, each being associated to a different one of the image carriers, for transferring the toner images carried by the image carriers to the transfer medium, wherein: the transfer rollers are fabricated in a crown shape and so that the crown quantities of the crown shapes of the transfer rollers decrease in stages towards a downstream side along the transport direction of the transfer medium.

Abstract: In an image forming apparatus including a transfer and transport belt suspended between a plurality of rollers, an image forming section for forming a pattern image on the transfer and transport belt, and a pattern image detecting sensor for detecting the pattern image, the pattern image detecting sensor is disposed so as to detect the surface of a suspended segment, of the transfer and transport belt, suspended between the rollers, and a back surface contact member that is in contact with a back surface of a detection area where the pattern image detecting sensor detects the pattern image on the surface of the transfer and transport belt is provided so as to render the detection area flat and stable. This can provide an image forming apparatus incorporating a pattern image detecting means having a simple arrangement and a capability to surely detect the pattern image in a precise and stable manner.

Abstract: The present invention includes:

Abstract: Photoreceptor drums for forming color images each have a gear as the drive transmission element at their central shafts. Each gear has an idle gear which in turn is coupled with a first motor via a timing belt. The photoreceptor drum for forming black monochrome images has a gear as the drive transmission element at its central shaft. This gear has an idle gear which is coupled with a second motor.

Abstract: The image forming apparatus includes: an image forming portion having a multiple image forming stations each forming a color separated image; a transfer device for superimposing and transferring color separated images; a pattern image forming device for forming a predetermined pattern image; a pattern image density measuring device for measuring the density of the pattern image. In this configuration, the pattern image is formed so as to be greater than the measuring area of the pattern image density measuring device and is formed of multiple lines having a line width and a line spacing so that any part of the pattern image within the measuring area will produce an approximately constant measured density value.

Abstract: A sheet conveyance guide is configured of separation claws for separating the paper from a conveyer and transfer belt and a movable sheet guide for guiding the paper to a fixer entrance sheet guide. The separation claws are arranged on the upstream side of the movable sheet guide. The movable sheet guide is rotatable about a pivot shaft with its distal end abutted by gravity upon the upstream end part of the fixer entrance sheet guide.The separation claws and movable sheet guide are axially supported so as to rotate on pivots.The sheet conveyance guide moves together with the vertical movement of the conveyer and transfer belt while the abutment point of the separation claws upon the conveyer and transfer belt moves to the appropriate position.

Abstract: In a paper-punching device for use in an image-forming apparatus, the rear edge of a sheet of paper that is being transported through a transport guide is detected by the photosensor. After a predetermined time has passed since the detection, a punching device is activated. At this time, a punching member is depressed downward, and a punching blade attached to its top penetrates through the sheet of paper, thereby forming a punch hole. Even during the punching operation, transport rollers continue to rotate. Therefore, when the sheet of paper is caught by the punching blade, the transport rollers are allowed to slip predetermined amount with respect to the paper. For this reason, at least one of the transport rollers is made of a foamed material. With this arrangement, since the punching operation is carried out on the rear side of the sheet of paper, it becomes possible to reduce the occurrence of paper jams even if sheets of paper are transported in succession.