Abstract: A color image forming apparatus having an image retainer, a transfer member and selection device for selecting one of a monochromatic mode for forming a monochromatic toner image on the transfer member and a multicolor mode for forming a multicolor toner image composed of a plurality of monochromatic toner images on the transfer member. The maximum length of the multicolor toner image is limited within a size corresponding to an effective peripheral length of the transfer member when the multicolor mode is selected.

Abstract: In an image forming apparatus, there is provided a multistage exit tray to receive printed recording sheets, which is located above an upper cover to access a conveyance path of the printed recording sheets within the apparatus by opening the upper cover upwardly. When the upper cover is opened, the exit tray is moved to a position where the exit tray does not interfere with the upper cover.

Abstract: A color copier which can be adopted to a printer operation for a peripheral imaging machine. The color copier forms plural color component toner layers on a photoreceptor layer by layer at each rotation of the photoreceptor. In the mode that the color copier is used as a printer, the copier makes two pages of each of the color component toner layers corresponding to an image at one rotation of a rotatable photoreceptor, when the size of the image is not more than one half the maximum size that can be formed by the copier.

Abstract: The invention provides a color image forming apparatus with photoreceptor belt. In a roll of the photoreceptor belt provided two pieces of rotatable rollers and guide plate with a curved surface so that the photoreceptor belt is moved while slidably coming in contact with the curved surface of the guide plate. Along the outer surface of the roll of the photoreceptor belt provided a plurality of developing devices at the curved surface to form a color toner image on the photoreceptor belt.

Abstract: A color image forming apparatus in which a guide member, provided between two revolving rollers around which a belt type image carrier is stretched, and on which the belt is slidably conveyed, has a large convex curvature in the direction of belt conveyance, so as to reduce friction between the belt and the guide member. A plurality of developing devices are provided to face the belt type image carrier and include magnetic rolls in which a magnetic pole facing the belt type image carrier most adjacently and one of magnetic poles next to the magnetic pole are disposed at a specific angle. The following formula is satisfied:L/R<.theta.where R is the radius of curvature of the guide member, L is the maximum length of the belt type image carrier along the circumferencial surface of the belt type image carrier facing the plurality of developing devices and .theta. represents the specific angle.

Abstract: A printer having an automatic removable cartridge. The cartridge has at least one of a photoreceptor, a developer, and a cleaner. The cartridge is automatically removed from the printer at a part when an operator opens the upper cover of the printer, or the printer senses an inside paper jam. The operator can remove the cartridge completely from the printer after it is partially removed by the automatic operation. The printer also includes an operating panel or the like to forcefully remove the cartridge from the printer by a command of the operator.

Abstract: A color image forming apparatus in which at least one registration mark is formed on a movable image retainer, and exposed by an exposing device. A position of the registration mark is detected by a detecting device and a signal is generated based on the detected position of the registration mark. An exposing position of the exposing device is corrected by a correcting device in accordance with the signal to form a latent image on the image retainer.

Abstract: The invention provides a sheet feed cassette for holding various sizes of sheets to be fed to an image recording apparatus in a feed direction. The cassette comprises a first casing having a sheet placement area, and a second casing slidably connected to the first casing for expanding the area. The first casing is detachably mounted on the image recording apparatus.

Abstract: An image forming device and method for an electrophotographic process wherein a digital image forming device forms an electrostatic latent image on a photoreceptor by beam modulation of digital image data from a computer or the like. The electrostatic latent image is formed in the form of dots by a light-modulated laser beam, and the electrostatic latent image is developed to form an image. A reference wave signal generating circuit is provided for generating a reference wave signal of a predetermined wave form, and a modulating circuit modulates an image density signal with the reference wave signal and outputs a modulated signal. The modulating signal is used to control a laser which emits light modulated in accordance with the modulating signal.

Abstract: A color image forming apparatus wherein a photosensitive belt trained around a plurality of rollers is moved along a guide member, and the guide member is in contact under pressure by an elastic member with a space retaining member provided in each of image forming members facing the photosensitive belt. A color image forming apparatus wherein a photosensitive belt trained around a plurality of rollers is moved along a guide member, and each of given space retaining members is mounted coaxially with each of developing sleeves in the developing devices is in contact under pressure with the side end of the guide member facing the photosensitive belt by an elastic member.

Abstract: A color image forming apparatus including a color image reader for optically scanning a document to produce blue, green, and red color separated information, a processor for processing the color separating information supplied by the reader and generating black, yellow, magenta, and cyan color information signals, a rotatable image retainer, and two latent image forming devices for forming latent images at a common region on the image retainer in accordance with the color information signals corresponding to two recording colors. The first latent image is formed by one of the latent image forming devices in synchronization with the scanning of the color image recorder to form a first latent image at a first writing position. The second latent image forming device is delayed to form the second latent image at a second writing position. The delay device compensates for the time necessary for the common region on the image retainer to travel between the first and second writing positions.

Abstract: The invention provides an apparatus for forming image, components of which are classified into two groups. A first group includes a photoreceptor on which an electrostatic latent image is formed, a charger for charging the photoreceptor, and a developing device for developing the latent image into a toner image; and a second group includes a transferring device for transferring the toner image to a recording sheet, a sheet passage for passing the recording sheet through the transferring device, and a toner container for storing toner. In the above constitution, the second group is arranged to dispose above the first group.

Abstract: A color image forming apparatus wherein an image retainer and a transfer member are arranged unitarily in a process cartridge, the process cartridge being formed so that it can be inserted into and withdrawn from an apparatus body having a pluralilty of developing devices. The process cartridge has a cleaning device and a transfer member, and the apparatus body has a device for recovering waste toner. The waste toner scraped off from a surface of the image retainer by the cleaning device is recovered into a hollow in the transfer member.

Abstract: A developing apparatus having a developing roll including therein a developing sleeve and a magnet roll to be faced to an image retainer for developing an electrostatic latent image on the image retainer with a developer. A partition plate is provided between developer agitating members disposed below the developing roll. A developer removing device for removing the developer on the developing sleeve is provided on an upper portion of the partition plate.

Abstract: A color image reader for discriminating a color component of a light image, comprising a first photoelectric transfer device for transferring visible range light to an electric signal, a second photoelectric transfer device for transferring infrared range light to another electric signal, and a discriminator for discriminating between a chromatic portion of the light image and an achromatic portion of the light image according to the two different electric signals.

Abstract: In a color image forming apparatus has a interchangeable belt-shaped image forming body stretched between horizontally disposed rollers and a plurality of developing means located below the belt-shaped image forming body. A passage for the transfer paper conveyance unit preferably as well as a fixing unit can be opened so that a process unit comprising the above-mentioned belt-shaped image forming body can be attached to and detached from the apparatus in the same direction as the above-mentioned passage for the transfer paper conveyance unit.Furthermore, the feeding operation for a sheet by-pass or loading and unloading operation for the recording paper cassette can be also carried out in the same direction as the above-mentioned passage of the transfer paper conveyance unit.

Abstract: An image forming apparatus wherein a recording paper receiving cassette can be moved to a first position where the cassette is stored in the apparatus body and a second position where one portion of the cassette is withdrawn from the apparatus body so that the paper feed can be carried out, wherein when the cassette is withdrawn further from the apparatus body the cassette can be removed from the apparatus body. A process cartridge including a photosensitive belt and a plurality of developing devices are arranged around the photosensitive belt. The process cartridge is disposed above the recording paper receiving cassette, wherein the process cartridge can be withdrawn in the same direction as that of the recording paper receiving cassette when the recording paper feed path is opened.

Abstract: An image forming apparatus having a cassette for containing copy sheets, the cassette being releasable responsive to the opening of an upper cover to cover an upper portion of the apparatus. The image forming apparatus may be further provided with a cartridge for carrying at least one of an image carrying body, developing units and a cleaning unit, and the cartridge is also released responsive to the opening of the upper cover of the image forming apparatus.

Abstract: The invention provides a color image forming apparatus provided with an image carrying unit including a rotatable photoreceptor, a developing unit including a plurality of developing devices, and a cleaning unit. The apparatus is formed with a lower casing and an upper casing. In the upper casing, the image carrying unit, the developing unit and the cleaning unit are accommodated, in which at least two kinds of the units are incorporated in a cartridge capable of being detachably installed in the upper casing. The upper casing is adapted pivotal between an open position and an operation position around an axis which is disposed parallel to the rotation axis of the photoreceptor. When the upper casing is pivotted to the open position, the developing unit is so disposed that a side of the developing unit facing the photoreceptor becomes higher than other side of the developing unit.

Abstract: A color image forming apparatus wherein a belt-shaped image retainer faces an image forming device. The image forming device includes a charging device, exposure device and a plurality of developing devices which are juxtaposed with each other. The belt-shaped image retainer is in the form of a cartridge which is mounted removably in the apparatus body. The cartridge has a closable cover divided into several sections which are arranged at the positions facing the image device. The belt-shaped image retainer has a transversely movable shutter member for protecting spaced apart surface portions of the image retainer which would be otherwise exposed when the upper casing of the apparatus body is opened or when the image retainer is removed from the upper casing, by moving the shutter member transversely to cover the spaced apart exposed surface portions of the image retainer.