Abstract: An object of the present invention is to provide an image forming apparatus that has an amorphous silicon photosensitive body, charging device for charging the photosensitive body, the charging device including a magnetic brush which is brought into contact with the photosensitive body and is formed by a magnetic particle layer, and pre-exposing device for exposing the photosensitive body after an image formed on the photosensitive body is transferred to an image receiving member before the photosensitive body is charged by the charging device, the pre-exposing device exposing the photosensitive body with an exposure width smaller than a width with which the charging device charges the photosensitive body in a longitudinal direction of the charging device.

Abstract: The present invention relates to an electrophotographic apparatus including decreasing means for decreasing the potential difference between the potential of the toner-adhering portion of the photosensitive body and the potential of the toner-non-adhering portion of the photosensitive body after the development by the developing means and before the transfer by the transferring means.

Abstract: An electrophotographic image forming apparatus in which an electrostatic latent image is formed on a charged surface of a photoconductive drum. The image is developed with toner into a toner image and the toner image is transferred to a recording medium. A charging roller is in contact with the photoconductive drum and charges the photoconductive drum when the charging roller receives a high voltage. A detector detects a characteristic such as an electrical resistance of the charging roller and outputs a signal indicative of the characteristic. A charging power supply applies a high voltage to the charging roller, the voltage having a value in accordance with the signal. A neutralizing device neutralizes the charged surface of the photoconductive drum before the detector detects the characteristic of the charging roller but does not neutralize the charged surface of the photoconductive drum when the electrostatic latent image is being formed.

Abstract: An image forming apparatus including a photoconductive member, a charging member, a development mechanism, a transfer mechanism, and a power supply source. The development mechanism develops an image on the photoconductive member. The toner is normally charged with a voltage having a same polarity as the charge of the photoconductive member. The transfer mechanism includes a transfer roller to transfer the developed image from the photoconductive member onto a recording sheet. The power supply source supplies a voltage, having the same polarity as the voltage applied during a normal transfer operation, to the transfer roller when a region of the surface of the photoconductive member passes through a development region without a performance of a development operation and reaches a transfer region under a condition in which no recording sheet exists therebetween.

Abstract: A xerographic printer includes a rotatable photoreceptor which is exposed, with each cycle, by a regular exposure device to create an image desired to be printed. Elsewhere along the photoreceptor is disposed a supplemental discharge device which discharges only those small areas on the photoreceptor which were not discharged by the regular exposure device within the cycle. In this way, every small area of the photoreceptor is evenly discharged within each cycle, and thus every small area of the photoreceptor experiences the same amount of aging. The system is particularly useful for full-color xerographic printers, in which the photoreceptor is repeatedly discharged by different exposure devices within each cycle.

Abstract: An electrophotographic image forming apparatus includes: a process cartridge, including at least one photo-receptor on which a toner image is formed, and a charging device, configured to uniformly charge a surface of the at least one photo-receptor; and a discharging device, provided outside of the process cartridge and configured to emit light to discharge the surface of the at least one photo-receptor. The process cartridge includes a light incidence opening to pass the light emitted from the discharging device therethrough, and the light incidence opening is formed to regulate the passed light so as to irradiate an area of the surface of the at least one photo-receptor.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic image; developing means for developing the electrostatic image on the image bearing member with toner electrically charged to a predetermined polarity; transfer means for transferring the toner image from the image bearing member to a transfer material; toner charging means for electrically charging residual toner remaining on the image bearing member to the same polarity as the predetermined polarity; and an image bearing member charging means for contacting to the image bearing member carrying the toner charged by the toner charging means to electrically charge the image bearing member to the same polarity as the predetermined polarity, the image bearing member charging means being effective to reduce a charge amount of the toner.

Abstract: A light source within a photocopy machine continuously shines high level, wide band fluorescent light on the photoreceptor to maintain the photoreceptor in a uniformly light-shocked condition. This constant level of light shock has no adverse effects on either the life or performance of the photoreceptor in normal operation. Thus, the photoreceptor becomes less sensitive to unintentional, uneven ambient room light and random, long lasting delta voltages within the print area are reduced so that print quality defects are minimized.

Abstract: An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The image forming apparatus further includes a member which charges the transfer paper in a polarity reversed to a polarity of the transfer drum, so that the transfer drum can attract the transfer sheet electrostatically in a satisfactory manner. The image forming apparatus further includes a charge control mechanism for controlling the amount of charges on the photosensitive drum.

Abstract: A light source within a photocopy machine continuously shines high level, wide band fluorescent light on the photoreceptor to maintain the photoreceptor in a uniformly light-shocked condition. This constant level of light shock has no adverse effects on either the life or performance of the photoreceptor in normal operation. Thus, the photoreceptor becomes less sensitive to unintentional, uneven ambient room light and random, long lasting delta voltages within the print area are reduced so that print quality defects are minimized.

Abstract: An electrophotographic process is implemented with improved ghost memory and with high chargeability even under circumstances of increased process speed or compactified structure and the electrophotographic process forms an image on a photosensitive member having a photosensitive layer through a series of steps including steps of charge elimination, charging, latent image exposure, and development to form a toner image, wherein light used in the latent image exposure step is light of a wavelength within such a range that a value of (optical memory before charging)/(sensitivity) of the photosensitive layer is not more than 1.5 times a minimum value. The optical memory before charging means lowering in chargeability due to light irradiation before charging.

Abstract: An image-forming apparatus includes a photosensitive member having a gamma for latent image of 3 or more, electrification facilities, light exposure facilities, image development facilities, image transfer facilities, cleaning facilities, and a charge erasing light source which applies an alternating current electric field at a frequency of 50 Hz to 1 kHz to a portion of the photosensitive member which is excited through light exposure by the charge erasing light source. Images with high quality and high resolution can be stably formed without residual images, even when continuous image formation is performed by utilizing a high gamma electrophotographic photosensitive member.

Abstract: An electrostatographic printing machine that includes an erase light source that reduces the quantity of charges on the photoreceptor surface and a reconditioning light source that reduces both the quantity of the trapped charges and the variation in the quantity of the trapped charges among the different portions of the image area.

Abstract: An image forming apparatus includes (i) a photosensitive drum for holding an electrostatic latent image on its surface, the photosensitive drum being driven to rotate by a motor, (ii) charging means for charging the surface of the photosensitive drum so that the surface has a predetermined polarity and a predetermined potential, (iii) exposing means for forming an electrostatic latent image by exposing the charged surface of the photosensitive drum, and (iv) developing means for developing the electrostatic latent image, and is arranged so that after stop of the motor due to occurrence of a trouble, during an inertial rotation time in which the photosensitive drum rotates due to an inertial force, the exposing means executes discharge exposure with respect to a charge remaining region on the surface of the photosensitive drum.

Abstract: The present invention relates to an electrophotographic apparatus in which the apparatus is provided with a sequence in which a dark portion and a light portion are formed on a first portion and a second portion, respectively, on a photosensitive member by an electrostatic image forming device, whereafter the first portion and the second portion are exposed by a pre-exposure device, and then the first portion and the second portion are charged by a charger, and then a surface potential of the first portion and the second portion are detected by a detector, and an exposure amount at which the photosensitive member is exposed by the pre-exposure device is controlled in conformity with the potential of the first portion and the potential of the second portion detected by the detector in the sequence.

Abstract: A method involving a photoreceptor having a front surface and a rear surface, including: (a) creating an electrostatic latent image on an image area of the photoreceptor front surface; (b) developing the latent image with developer particles to form a developed image; (c) transferring the developed image off the photoreceptor wherein the photoreceptor retains residual charges in the image area after the transferring of the developed image off the photoreceptor; and (d) discharging at least a portion of the residual charges in the image area, after transferring the developed image off the photoreceptor, by directing charge dissipation emissions at a portion of the image area and at a corresponding region on the photoreceptor rear surface directly opposite the image area portion.

Abstract: An electrophotographic apparatus includes a photosensitive member and an electrostatic image forming apparatus for forming an electrostatic image on the photosensitive member. The electrostatic image forming apparatus includes a charging device for electrically charging the photosensitive member and an exposure device for exposing the photosensitive member charged by the charging device. A developing device forms a toner image by developing the electrostatic image with toner. A transfer device electrostatically transfers the toner image onto a transfer material, wherein the photosensitive member has characteristics such that a rate of change of surface potential of the photosensitive member relative to a change of an exposure amount of the photosensitive member, is smaller in the case of a first exposure amount than in the case of a second exposure amount which is larger than in the first exposure amount.

Abstract: The present invention provides a simplified configuration to an image forming apparatus having a photoconductive member by making use of a waveguide (light propagation) member capable of easily diverging and/or refracting light so that the photoductive member is discharged.

Abstract: The present invention relates to an image forming method in which charges are injected into an image bearing member having a charge injecting layer on a surface thereof to thereby charge it to a predetermined polarity and charges of an opposite polarity to the predetermined polarity are imparted to the image bearing member before image formation.

Abstract: An electrophotographic printing machine has a photoreceptive member. The photoreceptive member is charged and then exposed with a light image representation to form a latent image. An electric field, less than that required to re-charge the photoreceptive member, is applied to the latent image to increase the rate of discharge of the exposed portions of the latent image. The latent image is then developed.

Abstract: In an electrostatic printing apparatus, the residual image phenomenon conspicuously observed at low density printing can be eliminated while photo-deterioration of the photosensitive body is being suppressed to a minimum in a high speed printing process. A charging unit, a writing light source, a developing unit, a transfer unit, a first erase lamp, an AC discharging unit and a second erase lamp are arranged around a photosensitive drum. Therein, the light intensity of the erase lamp is strengthened when the density of a printed image is light and is weakened when the density of the printed image is dark. That is, by changing the light intensity of the erase lamps corresponding to a developing bias, the residual image phenomenon can be eliminated while suppressing deterioration of the photosensitive drum to a minimum.

Abstract: In a color image forming apparatus provided with a photoreceptor having a rotatable peripheral surface; plural sets of a charging device, an imagewise exposure device, and a developing device, each set of the plural sets is provided separately from other sets around the peripheral surface of the photoreceptor so that plural color component images are formed one after another by the plural sets and are superimposed so as to form a color image on the peripheral surface during a single rotation of the peripheral surface. The developing device has a casing and the imagewise exposure device and the developing device of each set are arranged such that a portion on the peripheral surface locating at an imagewise exposing position moves into the casing of the developing device before the electric potential V1 of the portion is lowered to the half of V1 (V1/2).

Abstract: An image forming apparatus employs an image carrier (photoreceptor) cartridge having protective covers of which surface is coated with conductive shield in order to prevent frictional charging that will bring on sparking between a photoreceptor and covers. Further, the photoreceptor cartridge is equipped on its surface with an elastic member which is a foam body having a plurality of foam cells for catching foreign matter such as paper particles in order to prevent the foreign matter from damaging the surface of the photoreceptor. Moreover, the photoreceptor cartridge is also equipped with a flick member for flicking off toner deposited on a conductive brush in order to prevent the brush from becoming dirty. Owing to the above-mentioned construction, the image forming apparatus can avoid degradation in image quality.

Abstract: An erasing device includes a sheet-like erasing member. The erasing member is supported by an electric charger in contact with the image bearing member for erasing a residual electric charge from the image bearing member. Preferably, the erasing member is supported by a supporting member which in turn is supported by the electric charger. Therefore, the erasing member can be disposed relative to the image bearing member with a greater precision without using any additional rigid member. Also, the image bearing member can be erased without any defect, which results in that the image bearing member is uniformly charged in the subsequent charging.

Abstract: An image forming apparatus of the present invention includes an image forming unit to form a developer image on an image carrier, a transfer unit to transfer a developer image on an image receiving medium, a conveyor belt provided in contact with the transfer unit to carry and convey the image receiving medium with a developer image transferred by the transfer unit and a voltage applying portion to apply voltage to the transfer unit. This image forming apparatus further includes a controller to control voltage to be applied by the voltage applying portion to at least either one of the leading edge portion and the trailing edge portion of the image receiving medium in the direction conveyed by the conveyor belt so that it becomes higher than voltage to be applied to the middle portion in the conveying direction of the image receiving medium.

Abstract: Applied voltage to the contact charging sheet 71 has been controlled in the following various ways: a) the voltage at the photosensitive layer 10 at a point of time whereat it has passed the contact charging sheet 71 is caused to interlock with grid voltage so as not to exceed predetermined voltage to be electrified by the Scorotron charger 2; b) the applied voltage is caused to interlock with the output from the transfer unit 5 so that there is no portion which reaches the Scorotron charger 2 while the potential polarity has been reversed at the transfer unit 5; c) reduction in the film thickness of the photosensitive layer 10 is corrected in consideration of the cumulative number of sheets for image formation; d) the size of printing sheet is added; e) at the time of termination, a portion of the photosensitive layer 10, into which current has flowed at the transfer unit 5, is caused to stop always after passing the contact charging sheet 71; f) the contact charging sheet 71 is cleaned by means of AC compon

Abstract: An image forming apparatus of the present invention includes a latent image forming unit to form an electrostatic latent image on a charged image carrier, a developing device to form a developer image by developing the electrostatic latent image formed on the image carrier by a developer and a charge removing unit to discharge the image carrier before transferring the developer image and reduce the electrostatic adsorbing power of the developer image to the image carrier. The charge removing unit includes a charge removing light source to apply the charge removing light to the image carrier and the developer image and the charge removing charger to remove the charge by discharging the image carrier and able to control the discharge output. The charge removing unit is controlled to be adjusted a charge removing capacity.

Abstract: A control circuit for outputting a signal for controlling an amount of light emitted from a plurality of light emitting elements. The control circuit includes a controller or CPU, and a D/A converter outputting a signal for setting a voltage in multiple gradation in accordance with a lighting state of the light emitting element. An amplifying circuit amplifies an output of the D/A converter and outputs an amplified output as a control signal. A reference voltage generating circuit generates a reference voltage and a comparator compares the control signal with the reference voltage. The controller varies an output of the D/A converter based on the result of comparison by the comparator, to adjust the output of the D/A converter so that the control signal is equivalent to the reference voltage. Accordingly each voltage is reset in the multiple gradation to allow the light emitting element to appropriately emit light based on the adjusted output.

Abstract: In an image forming method in which an image is formed through the charging, exposing, developing, transferring, and charge eliminating steps using an amorphous silicon photoreceptor having an amorphous silicon photosensitive layer, an image forming method according to the present invention is so adapted that letting t1 be a time period from the charging step to the developing step and t2 be a time period from the charge eliminating step to the charging step, the value of t2/t1 is not less than one.

Abstract: A destaticizer which is adapted to remove electric charges from the surface of a photoreceptor by exposing the photoreceptor surface to light. The destaticizer includes a light source, and a light guide member for generally uniformly guiding light from the light source to a light exposure area on the photoreceptor. In accordance with one embodiment, the light guide member is an elongated member, which has an end face serving as a light receiving face for receiving the light emitted from the light source, a light transmitting path for transmitting the light received by the light receiving face, and a plurality of reflecting portions arranged along the length of the light guide member for reflecting the light transmitted through the light transmitting path in a direction intersecting the length of the light guide member.

Abstract: The present invention relates to image forming device such as copying machines and laser printers, which use an electrophotographic (xerognaphic) process. A simple control method without using any additional complex means can equalize a surface potentional of a light-sensitive drum to keep a light-quality of an image formed even for the first rotation of the light-sensitive drum. A charge-removal prohibiting means, a charge-potentional changing means and a developing bias-potentional changing means are controlled in accordance with an extent of a change of a surface potential of a light-sensitive body, which depends upon a light fatigue and an ambient temperature of the light-sensitive body and/or a pause after a preceding image process.

Abstract: An image forming apparatus which collects residual toners on a latent image carrier in a developing unit. The image forming apparatus have a rotary endless latent image carrier; an image forming unit for forming an electrostatic latent image on the latent image carrier; a developing unit for developing the electrostatic latent image on the latent image carrier with a powdery developer and collecting residual toners on the latent image carrier at a same time; a transfer unit for transferring the developed image on the latent image carrier onto a sheet; a distribution member for distributing residual toners on the latent image carrier when in contact with the latent image carrier after image transfer; and a voltage supplying unit for supplying an AC voltage to the distribution member.

Abstract: In an electrophotographic process using an electrophotographic photoconductor having a photoconductive layer which contains a charge generation material and a charge transport material, the charge transport material being convertible from a neutral state into a charged state during the photoconduction in the photoconductive layer, when light is applied to the photoconductive layer, there is employed at least one type of rays of light selected from type 1 which has a light emission peak, and type 2 and type 3, each of which has a continuous spectrum with a threshold wavelength value, in such a manner that a half-width wavelength range of type 1 does not overlap a peak wavelength or a half-width wavelength range of an absorption peak of the charge transport material in the charged state, and a half value of a threshold wavelength value of each of type 2 or type 3 is beyond the wavelength or a half-width wavelength range of any of extreme end absorption peaks in terms of the wavelength of the absorption light of

Abstract: An image forming apparatus includes a photosensitive member; a charging member for charging the photosensitive member; an exposure device for exposing an image formation area of the photosensitive member charged by the charging member to light in accordance with an image signal to for an electrostatic image, and for exposing non-image-formation area around the image formation area to spots of light; and a developing device, having a developer carrying member for carrying a layer of developer having a thickness smaller than the gap with which the developer carrying member is opposed to the photosensitive member, for effecting reverse development of the electrostatic image.

Abstract: An image forming apparatus in which a toner image formed on an image carrier is transferred onto paper held onto a transfer drum following which the paper is separated from the transfer drum, the image forming apparatus being equipped with a charger that charges a prescribed area of the image carrier before the image carrier is uniformly charged, a mode setting device that sets the image formation mode, and a control device that controls the output of the charger in accordance with the image formation mode set by the mode setting device.

Abstract: An image forming apparatus of such a type as is provided with a photosensitive member having a semi-conductive intermediate transfer member disposed opposite the photosensitive member. A charger electrically charges the photosensitive member. An exposure device forms an electrostatic latent image on the photosensitive member and developer visualizes the electrostatic latent image using toner identical in polarity to the photosensitive member. A primary transfer device transfers the toner image to the intermediate transfer member by applying a bias opposite in polarity to the photosensitive member, and a secondary transfer apparatus transfers the toner image on the intermediate transfer member to a transfer material. An optical charge-eliminator optically removes the electrical charge from the photosensitive member.

Abstract: In an image forming apparatus forming an electrostatic latent image on a surface of a photosensitive body by exposing the charged photosensitive body, developing the latent image using a toner to form a toner image, transferring the toner image to a image holding body, and erasing the remaining charge on the surface of the photosensitive body after completion of the transferring, the photosensitive body is formed of a base material consisting of As.sub.2 Se.sub.3 or a-Si, and wherein the wavelength .lambda..sub.0 of the writing light used for the exposure is limited to a wavelength not larger than 780 nm, the wavelength .lambda..sub.1 of charge erasing light used for the charge erasing is limited to a wavelength smaller than 680 nm, and the time T.sub.1 from completion of the exposure to initiation of the development is limited within the range of 70 milliseconds to 300 milliseconds.

Abstract: A process for ascertaining the microdefect levels of an electrophotographic imaging member including establishing for a first electrophotographic imaging member, having a known differential increase in dark decay value and a measured crest value, a first reference datum for dark decay crest value at an initial applied field; establishing with the crest value a second reference datum for dark decay crest value at a final applied field; determining the differential increase in dark decay between the first reference datum and the second reference datum for the first electrophotographic imaging member; repeatedly subjecting a virgin electrophotographic imaging member, having a measured crest value, to aforesaid cycles until the amount of dark decay reaches the crest value for the virgin electrophotographic imaging which remains substantially constant; establishing with virgin electrophotographic imaging member, having a measured crest value, a third reference datum for dark decay crest value; establishing for the

Abstract: An image forming apparatus for forming an image on a sheet, including a rotary endless latent image carrier, an image forming device for forming an electrostatic latent image on a latent image carrier, a developing device for developing the electrostatic latent image on the latent image carrier with powdery developers and collecting residual toners on the latent image carrier at the same time, a transfer device for transferring a developed image on the latent image carrier onto a sheet, a distribution roller having independent foam perforations for distributing residual toners on the latent image carrier when in contact with the latent image carrier after image transfer, and a power supply for supplying an AC voltage to the distribution member. The distribution member is made of a conductive foam member having a pore at a surface contacting with the latent image carrier and the roller rotates in a direction opposite to a rotational direction of the latent image carrier at a peripheral velocity of 1.1 to 1.

Abstract: An image forming apparatus includes an image bearing member for bearing an image, the image bearing member being rotatable at a first speed and a second speed which is different from the first speed, wherein during image formation on the image bearing member, the first speed is selected, and after completion of image formation on the image bearing member, a speed of rotation of the image bearing member is switchable from the first speed to the second speed; a discharger for electrically discharging the image bearing member at a discharging position, the discharger discharging the image bearing member at least one turn after the trailing edge of the image on the image bearing member passes through the discharging position and before the speed of the image bearing member is switched from the first speed to the second speed.