Abstract: An image forming device, in accordance with the present invention, stores the correction factors produced during calibration cycles for future analysis. The correction factors, or alternatively, the new printer control parameters, which incorporate the correction factors, may be adjusted for current environmental conditions. During the calibration cycle, the correction factors produced during the current calibration cycle and old correction factors produced during prior calibration cycles are analyzed to determine if the printer control parameters are within desired degradation limits, which indicate that the print quality of the imaging forming device will degrade beyond acceptable limits prior to the next calibration cycle. Thus, a statistical analysis of the historical data produced during calibration cycles can be used to predict when the image quality of the image printing device will degrade beyond acceptable limits.

Abstract: The image forming apparatus has charging device, developing device, transfer-charging device, and control device for controlling a charging bias applied to the charging device. In the image forming apparatus, the transferring material to which the developer image is transferred is separated from the photosensitive body by the transfer-charging device, and the control device reduces the charging bias such that a surface potential of the photosensitive body in the case where the developer image is formed on the transferring material having low rigidity is lower than the surface potential of the photosensitive body in the case where the developer image is formed on the transferring material having high rigidity.

Abstract: In a print control method of an electrophotograph and an image formation apparatus thereof, a surface potential sensor is placed in a post-transfer area and at the position, the potential on the photoconductor drum surface at the developing point is detected. When the potential on the photoconductor drum surface is detected, the developing bias is avoided at the optimum timing and the potential is detected at the position after transfer. The correction potential amount grasped based on the in-machine humidity and the photoconductor drum film thickness previously measured is added to the detected potential and the potential on the photoconductor drum surface at the developing point is reproduced. Feedback control is applied to the potential on the photoconductor drum surface, whereby the developing potential on the photoconductor drum surface is kept stable.

Abstract: An image forming apparatus restricts disturbance of a potential patch in the case where a potential sensor for detecting the potential patch is provided downstream side of a developing device of a multiple developing roller type to enable stable reproduction of a high quality image for a long period. The apparatus includes a potential sensor provided downstream side of moving direction of the image carrier relative to the developing means for detecting a potential on the image carrier, and controller setting the developing bias to a value restricting disturbance of a potential portion as an object for potential detection by the potential sensor by the developer when the potential portion passes across the developing means.

Abstract: A charging device comprises a conductor, which is in contact with a photoconductor, and a power source circuit, which applies a voltage to the conductor and electrically charges the photoconductor as to have a predetermined level of potential. The power source circuit includes a resistor having a predetermined level of resistance, and provides the conductor with a voltage through the resistor, thereby to stabilize the charged potential of the photoconductor.

Abstract: An image forming apparatus includes an image-forming unit having a charging section and a developing section that are rotated together with a photoconductor in an idling manner. The charging section and developing section receive voltages while rotating. The apparatus includes a toner sensor and a controller. The toner sensor outputs a detection signal indicating that the toner has been replenished in the image-forming unit. In accordance with the detection signal, the controller changes the voltages, a time length during which the photoconductor, charging section, and developing section are rotated, or speeds at which the photoconductor, charging section, and developing section are rotated. The time length is extended or speeds are increased when the image-forming unit has been replaced.

Abstract: A first embodiment of a measurement system provides an indication of performance of an electrophotographic process. The first embodiment includes a charge measurement device coupled to a developing device and a high voltage power supply. The charge measurement device generates a signal corresponding to the net charge transferred between the high voltage power supply and the developing device during an imaging operation. The measured charge transfer is compared to an estimated charge transfer to determine if the electrophotographic process is operating correctly. The estimated charge transfer is determined by multiplying an estimate of the mass of the toner transferred during an imaging operation by an average value of toner charge to mass ratio. A sufficiently large difference in the magnitude between the measured charge transfer and the estimated charge transferred indicates that the electrophotographic process is not operating correctly.

Abstract: The present invention provides an image forming apparatus, which has an image bearing body for bearing a toner image, transferring device for transferring a toner image on the image bearing body to a transferring material, a charging member for charging the image bearing body, having a residual toner after the transfer on a surface thereof by being brought into contact therewith, electrostatic image forming device for forming an electrostatic image on the image bearing body charged by the charging member, developing device for collecting the residual toner on the image bearing body while developing the electrostatic image on the image bearing body by using a toner charged in the same polarity as a charging polarity generated by the charging member, control device for controlling a voltage to be applied to the charging member, and a cleaning sequence for performing a cleaning of the charging member by applying a voltage not higher than a discharge threshold and equal to the polarity of the toner after a discha

Abstract: An image forming apparatus includes an image bearing member; a charge member, contactable to the image bearing member, for electrically charging the image bearing member, the charge member being capable of being supplied with a voltage; developing means for developing an electrostatic image formed on the image bearing member with a developer; wherein the charge member is rotatable so as to provide a first peripheral speed difference between a surface of charge member and a surface of the image bearing member when the image bearing member is charged for image formation; wherein there is provided a cleaning period for transferring the developer from the charge member to the image bearing member with a second peripheral speed difference, which is smaller than the first peripheral speed difference, between the surface charge member of and surface of the image bearing member, when a charging operation for the image formation is not effected to the image bearing member.

Abstract: An object of the present invention is to provide an image forming apparatus in which a frequency of the oscillating voltage is a first frequency when a peripheral speed of the image bearing member is a first peripheral speed, the frequency of the oscillating voltage is a second frequency when the peripheral speed of the image bearing member is a second peripheral speed, and the determining device determines a first peak-to-peak voltage of the oscillating voltage corresponding to the first peripheral speed and the first frequency and a second peak-to-peak voltage of the oscillating voltage corresponding to the second peripheral speed and the second frequency, based on the first and second and third alternating currents in use of the first peripheral speed and the first frequency.

Abstract: An image forming apparatus includes a voltage control circuit and a decision circuit. The voltage control circuit varies a voltage to be applied to a charge roller at preselected intervals in correspondence to the non-image area of a photoconductive element. A photosensor senses the reflection density of a particular control pattern formed on the drum 1 before and after the above voltage is varied. The voltage control circuit controls the voltage to be applied to the charge roller in accordance with a ratio between the resulting outputs of the photosensor. The decision circuit determines, at the start-up of the apparatus, whether or not to cause the voltage control circuit 31 to execute the voltage control in accordance with ambient temperature sensed by a temperature sensor. If the ambient temperature is higher than a reference temperature, the voltage control circuit is inhibited from executing the control.

Abstract: The present invention relates to an image forming apparatus in which voltage is applied to an intermediate transfer body when a toner image is transferred from an image bearing body to the intermediate transfer body, and a controller controls variably a potential of a shadow portion of an electrostatic image so that a potential difference between the potential of the shadow portion and the voltage can be variable on the basis of a detected result of a detecting circuit.

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

Abstract: An image forming method and image forming apparatus in which a toner image formed on an image carrier (11) through steps of discharging, main charging, exposure and development is transferred to a recording medium (S) and then fixed as an image using flash light. The image forming apparatus (10) has a secondary charger (17) for secondarily charging the image carrier to have the same polarity as a polarity given by a main charger (12) and a surface potential larger in absolute value than a surface potential given by the main charger.

Abstract: An image forming apparatus has a monochrome mode for forming an image in a single color and a full-color mode for forming a full-color image in multiple colors. The image forming apparatus includes a photoconductor, a charging member contacting the photoconductor and charging the photoconductor with electricity, a power supply for applying, to the charging member, a DC voltage or a voltage including a DC voltage and an AC voltage in superimposed relation, and a unit for changing an AC component of the voltage applied to the charging member between the monochrome mode and the full-color mode.

Abstract: An image forming apparatus has an image forming device for forming a toner image on a recording material and a fixing device for fixing the toner image on the recording. An image forming speed at which the toner image is formed by the image forming device is adapted to be selected to be a first speed or a second speed greater than the first speed. A control device is provided so that, when the second speed is selected, a maximum toner amount per unit area of the toner image becomes smaller than that when the first speed is selected.

Abstract: An electrophotographic device having a control section (11) for controlling operations of charging units (2-1 to 2-4), exposure units (3-1 to 3-4), and other units so that forces against previously developed toners, close to subsequent toner area where no previously developed toner is present, wherein the previously developed toner area is not exposed during the subsequent selective exposure process, satisfy a desired condition-equation (equation (5)) when the exposure unit (3-1 to 3-4) selectively exposed the subsequent toner forming area after the completion of the previous development process for the previous toner and the subsequent charging process.

Abstract: By providing a printing density controller for changing a printing density in a range from a dropout color to non-dropout color, an electrophotographic printing apparatus can conduct the light and shade adjustment of the printing density in a broad range, and also cope with the dropout color printing.

Abstract: This image-forming device comprises information-detecting means for detecting information A regarding first processing means and information B regarding second processing means, and judging means for judging, according to the information A, whether or not a regulation of the first processing means needs to be performed. When the judging means judges that the regulation of the first processing means needs to be performed, a first regulation mode is performed in which the regulation of the first processing means is performed, the information-detecting means detects at least the information B, and a regulation of the second processing means is performed according to the information B. When the judging means judges otherwise, a second regulation mode is performed in which the first regulation mode is not performed, and the regulation of the second processing means is performed according to the information B.

Abstract: This specification discloses an image forming apparatus comprising a process cartridge detachably mountable with respect to the main body of the apparatus, the process cartridge being provided with an image bearing member and charging means for charging the image bearing member, a power supply for applying an alternating current voltage to the charging means, and control means for variably controlling an alternating current supplied from the power supply to the charging means in conformity with information about the use situation of the process cartridge. The specification also discloses a process cartridge detachably mountable with respect to the main body of the image forming apparatus.

Abstract: An object of the present invention is to provide a process cartridge detachably mountable to a main body of an image forming apparatus, which has an image bearing member, a charging member for charging the image bearing member while the charging member is in contact with the image bearing member, and storage device for storing information concerning the type of the charging member.

Abstract: An image-forming apparatus for forming an image by electrically charging a photosensitive material, forming an electrostatic image through the exposure to light and developing the electrostatic image, wherein the main charged potential (Vo) of the photosensitive material, the potential (Vr) of the exposed portion of the photosensitive material and the developing bias potential DB are so set as to satisfy the following formulas (1) and (2),

Abstract: The present invention relates to a corona charging apparatus for charging a body to be charged that has a discharge wire electrode to which a voltage is applied, a shield electrode having an opening opposed to the body to be charged, a grid electrode disposed in the opening, a power supply for applying a voltage to the grid electrode, and a constant voltage generating element electrically connected to the grid electrode, the constant voltage generating element generating predetermined voltage when current flows into the constant voltage generating element, and rated voltage of the constant voltage generating element is equal to or greater than the voltage applied to the grid electrode from the power supply.

Abstract: In an apparatus, first and second processing modes are prepared to determine an optimal development bias. Either one of the first processing mode and the second processing mode is selected as a processing mode in accordance with an operation status of the apparatus. Hence, it is possible to select and execute the most appropriate processing mode in accordance with an operation status to thereby efficiently and highly accurately determine an optimal value of a development bias which is one density controlling factor.

Abstract: An image forming apparatus includes an image bearing member; a charge member for electrically charging the image bearing member while contacting to the image bearing member: voltage applying means for applying an oscillating voltage including a component of AC voltage to the charge member; first detecting means for detecting an average of the AC current applied to the charge member from the voltage applying means; second detecting means for detection a value of the AC current corresponding to a peak of the AC voltage; and control means for effecting control such that when a detected current value of the detecting means is smaller than a first predetermined value, the detected current value of the first detecting means is at the first predetermined value, and when the detected current value of the first detecting means is larger than the first predetermined value, a current value of the second detecting means is at a second predetermined value.

Abstract: An image forming apparatus includes a constant-current power supply to supply operation currents to a charging unit and a removing unit, and keep the total of the operation currents at a predetermined value; and a correction circuit to detect a fluctuation in the operation current of the removing unit, and correct the predetermined value of the constant-current power supply circuit according to the detection results.

Abstract: In the charging device, a frequency f(Hz) is set so that a frequency f(Hz) of an AC voltage to be applied to a charging member and a movement rate v (mm/sec) of the surface of an image carrier satisfy f(Hz)≧40(1/mm)·v(mm/sec).

Abstract: An image forming apparatus including an image bearing member; a charge member contacted to the image bearing member to electrically charge the image bearing member; voltage applying means for applying to the charge member an oscillating voltage including an AC voltage component; first detecting means for detecting an AC current applied to the charge member from the voltage applying means; second detecting means for detecting the AC current corresponding to a peak or a neighborhood of the peak of the AC voltage; control means for effecting control such that current detected by the second detecting means is a predetermined level when the current detected by the first detecting means is within a predetermined range and such that current detected by the first detecting means is a predetermined level when the current detected by the first detecting means is outside the predetermined range.

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 includes a voltage control circuit and a decision circuit. The voltage control circuit varies a voltage to be applied to a charge roller at preselected intervals in correspondence to the non-image area of a photoconductive element. A photosensor senses the reflection density of a particular control pattern formed on the drum 1 before and after the above voltage is varied. The voltage control circuit controls the voltage to be applied to the charge roller in accordance with a ratio between the resulting outputs of the photosensor. The decision circuit determines, at the start-up of the apparatus, whether or not to cause the voltage control circuit 31 to execute the voltage control in accordance with ambient temperature sensed by a temperature sensor. If the ambient temperature is higher than a reference temperature, the voltage control circuit is inhibited from executing the control.

Abstract: An electrophotographic apparatus comprises: a photosensitive member; an electrostatic image forming unit, for forming an electrostatic image on the photosensitive member, including electrification means for electrifying the photosensitive member and an exposure unit for exposing the photosensitive member; a detector, for detecting a surface potential on the photosensitive member; a determination unit, for employing the detection results obtained by the detector to determine an electrification amount for the electrification unit and an exposure control value for the exposure unit, for determining the electrification amount for the electrification unit, so that a dark portion potential on the photosensitive member is substantially a target dark portion potential selected from multiple target dark portion potentials, for determining a first exposure control value for the exposure unit, so that a light portion potential, which is based on the determined electrification amount and which is formed on the photosensi

Abstract: An image forming apparatus includes an image bearing member for bearing a toner image; a transfer device for transferring the toner image onto a transfer material from the image bearing member; a charger for electrically charging the image bearing member, the charger being contactable to residual toner remaining on the image bearing member after transfer of the toner image by the transfer device; a voltage applicator for applying DC and AC voltages to the charger; an image forming device for forming an electrostatic image on the image bearing member charged by the charger; a developing device for developing the electrostatic image by toner; an integrator for integrating degree of usage of the apparatus; and a controller for controlling the AC voltage applied to the charger in accordance with the integrated degree of usage provided by the integrator.

Abstract: The value of an AC voltage ingredient applied to charging rollers in the mono-colored black image forming mode is reduced to be smaller than the value applied in the full-colored image forming mode. Accordingly, in the mono-colored black image forming mode, the electric discharge between the charging rollers and photosensitive drums which do not form images is reduced, so that a shaving-off phenomenon on the surfaces of the photosensitive drums can be decreased, and thereby increasing a lifespan of the photosensitive drums.

Abstract: An electrophotographic print engine has a variable primary charger and toning bias which places the machine in abnormal reproduction modes in order to provide service and diagnostic information to troubleshoot subsystems involved in the electrophotographic process.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming an image on the image bearing member and a detector for detecting the surface potential of the image bearing member, wherein a first image forming mode and a second image forming mode in which the image forming conditions of the image forming unit are different from each other can be selected, and further, the apparatus includes a controller for controlling the image forming conditions in the first and second image forming modes on the basis of the result detected by the detector for the first image forming mode.

Abstract: An image-forming apparatus is provided with: a rotatable photoreceptor; a charging device for charging the surface of the photoreceptor to a predetermined electric potential. A device for corona discharging, the charging device has a control electrode for controlling the quantity of corona ions that are allowed to reach the photoreceptor. A latent image forming device for forming an electrostatic latent image on the photoreceptor that has been charged by the charging device by use of light irradiation. There is a developing device for developing the electrostatic latent image by using a developer; and a control voltage supply device for supplying a control voltage to the control electrode and for switching the control voltage to a plurality of stages from a low-voltage side to a high-voltage side until the surface electric potential of the photoreceptor has risen to a predetermined electric potential.

Abstract: The image forming portion of this image forming apparatus includes a LSU, a photosensitive drum, a developing unit holder, a multiple number of developing units, an intermediate transfer element, a transfer element and a fixing unit. All the developing units are of an identical configuration. Therefore, for replacement of developing units, the operator may and should remove any color of developing unit in the same fashion and attach a fresh developing unit of the color in the same fashion. The image forming portion sets up the image forming conditions for individual colors in the developing order.

Abstract: An image forming apparatus comprising an image bearing member and electrostatic image forming means including electrification means which is disposed in contact with the above described image bearing member at an electrification location for injection electrification of the image bearing member, and configured to set a peripheral speed different between the above described electrification means and the above described image bearing member which is smaller when an area of the image bearing member to be an image forming area is at the above described electrification location than that when at least a portion of an area of the image bearing member to be a no-image forming area is at the electrification location.

Abstract: The present invention provides an image forming apparatus, which has an image bearing body for bearing a toner image, transferring device for transferring a toner image on the image bearing body to a transferring material, a charging member for charging the image bearing body, having a residual toner after the transfer on a surface thereof by being brought into contact therewith, electrostatic image forming device for forming an electrostatic image on the image bearing body charged by the charging member, developing device for collecting the residual toner on the image bearing body while developing the electrostatic image on the image bearing body by using a toner charged in the same polarity as a charging polarity generated by the charging member, control device for controlling a voltage to be applied to the charging member, and a cleaning sequence for performing a cleaning of the charging member by applying a voltage not higher than a discharge threshold and equal to the polarity of the toner after a discha

Abstract: An image forming apparatus capable of preventing contamination of a brush-roller charger with toner depositions includes a photoconductor, a brush-roller charger, an image development mechanism, an image transfer mechanism, a cleaning mechanism, a power supply mechanism, and a controller. The photoconductor carries an electrostatic latent image thereon. The brush-roller charger rotates in contact with the photoconductor and initializes a surface of the photoconductor by applying a charge thereto. The image development mechanism contacts the surface of the photoconductor and supplies toner to develop a toner image according to the electrostatic latent image on the surface of the photoconductor. The image transfer mechanism transfers the toner image from the photoconductor to a recording sheet. The cleaning mechanism cleans the surface of the photoconductor. The power supply mechanism supplies power to the brush-roller charger.

Abstract: There is provided a potential controlling method and potential controller of an image forming apparatus, which can certainly prevent toner and carrier from adhering to the surface of an image bearing body at the time of start and stop of image formation and which can also be applied to an image forming apparatus having a high image forming speed.

Abstract: A control method of a voltage to be applied to an electrifier includes the steps of measuring an integral value of an alternating waveform, and controlling an alternating current so that the integral value is constant in a predetermined time.

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: In a multiple-color image forming apparatus a voltage which is applied to the intermediate transfer member by the voltage applying device is constant-voltage-controlled, wherein there is a period when the image bearing member which is charged by the charger and on which no toner image is formed by the image forming device and the toner image which is transferred onto the intermediate transfer member exist at the transfer position, a detecting device for detecting a current that flows in the intermediate transfer member from the voltage applying device when the voltage is applied to the intermediate transfer member by the voltage applying device during the period, and a controller for controlling at least one of the voltage which is applied to the image bearing member by the charger and a voltage which is applied to the intermediate transfer member by the voltage applying device on the basis of a detection result by the detecting device.

Abstract: An image forming apparatus includes a photosensitive member, a charging device for charging the photosensitive member, an exposing device for exposing a light including image information to the photosensitive member, and a developing device for supplying a toner to an electrostatic latent image formed on said photosensitive member. The developing means is held by a cartridge removably mountable on a main body of the image forming apparatus. The cartridge includes a memory for memorizing an amount of use of the cartridge, wherein a charging amount of the toner caused by friction in the cartridge when the amount of use of the cartridge is in an initial state is smaller than that when the amount of use of said cartridge is not in an initial state. A judging device compares the amount of use of the cartridge with a predetermined value showing a condition that the amount of use of the cartridge is in the initial state.

Abstract: An image forming apparatus includes an image bearing member, an image forming device for sequentially forming toner images of different colors on the image bearing member, the image forming device including a charging member for electrically charging the image bearing member to a polarity which is the same as a regular charging polarity of the toner.

Abstract: A printer or copier has a photoconductor on which charge patterns are formed that are in turn inked and printed onto a recording medium. An optimized exposure energy is determined for a given potential of the photoconductor by calculating a sensitivity factor. The optimized charge potential may also be calculated on the basis of the sensitivity factor for a given exposure energy.

Abstract: An image is generated by exposing the surface to a scanning laser beam in accordance with an image forming process. The intermediate image transfer member receives the image from the image carrying member and transfers it onto a recording sheet. A memory stores a plurality of values of process line speeds A for defining a speed of an image forming process in a sub-scanning direction, and a plurality of values of process line speeds B for defining a speed of the image transfer process.

Abstract: An image forming apparatus capable of preventing unnecessary adhesion of a developer to an uncharged region of a latent image carrier. The image forming apparatus includes an endless latent image carrier, a charging unit for charging the latent image carrier, a latent image forming unit for forming a latent image on the latent image carrier charged, a developing unit for developing the latent image formed on the latent image carrier with a developer by supplying the developer to the latent image carrier under application of a developing bias voltage, and a transfer unit for transferring the image developed on the latent image carrier to a sheet.

Abstract: An image forming apparatus includes a charging element configured to apply a charging voltage to an image bearing member to charge the image bearing member, an optical writing device configured to form a latent image on a charged surface of the image bearing member charged by the charging element, a developer bearing member which carries developer including toner having a same polarity as that of the charging voltage to the image bearing member and which applies the toner to the latent image on the image bearing member to form a toner image when a developing bias voltage is applied thereto, and a control device which controls application of the charging voltage by the charging element and application of the developing bias voltage to the developer bearing member so as to increase an absolute value of the charging voltage to the image bearing member and an absolute value of the developing bias voltage to the developer bearing member to a predetermined value in a plurality of steps, respectively and wherein the