Abstract: A method of controlling a charging potential of an organic photoconductive cell (OPC) includes a first operation of applying two charging voltages Vc1 and Vc2 having respective duties D1 and D2 established in an engine controller unit (ECU) to a conductive roller via a high voltage power supply (HVPS) to charge the OPC, a second operation of measuring sensing voltages Vs1 and Vs2 through a sensing resistor Rs coupled to the conductive roller so that the ECU establishes a target charging current It and calculates a new charging voltage Vc3 and a new duty D3, a third operation of applying the new charging voltage Vc3 and the new duty D3 to the conductive roller via the HVPS to charge the OPC and measuring a charging current Ic3 of the conductive roller, and a fourth operation of comparing a difference between the charging current Ic3 of the conductive roller and the target charging current It with a tolerance value TOL to control the charging potential by using the target charging current when the difference is

Abstract: A charging apparatus includes a charging member, contactably provided to a member to be charged, for charging the member to be charged; voltage application means for applying alternating voltages having different peak-to-peak voltages to the charging member; and determination means for determining a peak-to-peak voltage to be applied to the charging member with respect to a second area of the member to be charged, on the basis of a peak-to-peak voltage corresponding to a minimum current which is not less than a predetermined current of alternating currents through the member to be charged when the alternating voltages having the different peak-to-peak voltages are applied to the charging member with respect to a first area of the member to be charged.

Abstract: A memory medium is provided to a cartridge detachably mountable to an image forming apparatus. Into the memory medium, as information for performing charge control, information on an amount of usage of an image-bearing member and information on a charging alternating voltage (a threshold value for selection control of charging peak-to-peak voltage Vpp) are written. The image forming apparatus includes a charging bias power supply circuit, on its body side, including AC oscillation output means capable of outputting two or more species of alternating peak-to-peak voltages and AC detection means for detecting an alternating current through the image-bearing member. Charge control is performed on the basis of a detected value detected by the AC detection means and memory information for the cartridge, whereby good charge control and space saving and cost reduction of the power supply circuit are compatibly realized.

Abstract: An apparatus and method for removing residual toner from a photosensitive drum wherein a first cleaning bias (600 V) is applied to a cleaning roller, a bias applied to a transfer roller is switched between a second transfer bias and a first transfer bias. The surface potential of a photosensitive drum changes depending on the bias applied to the transfer roller. When the photosensitive drum contacts the transfer roller while the second transfer bias is applied to the transfer roller, the surface potential of the photosensitive drum becomes the second surface potential (approximately 900-1000 V). When the photosensitive drum having the second surface potential contacts the cleaning roller, the cleaning roller collects toner remaining on the photosensitive drum. When the photosensitive drum contacts the transfer roller while the first transfer bias is applied to the transfer roller, the surface potential of the photosensitive drum becomes the first surface potential (approximately 200-400 V).

Abstract: The surface of an electrostatic recording member in an electrophotographic recording apparatus is charged to a standard primary charge V0s. The standard primary charge on the recording member is then modulated using a first test exposure E1 to form a first exposed test area, and using a second test exposure E2 to form a second exposed test area. A first test surface potential V1 is measured in the first exposed test area and a second test surface potential V2 is measured in the second exposed test area. A measured intrinsic sensitivity bm associated with the recording member is calculated using V1 and V2. A measured intrinsic toe dm associated with the recording member also is calculated using V1 and V2. A corrective charge parameter V0i is calculated using dm, and a corrective exposure parameter E0l is calculated using bm and dm. V0 is then adjusted to equal V0i, and E0 is adjusted to equal E0i.

Abstract: An image forming apparatus includes an image bearing member, a charging member, disposed so as to be contactable with the image bearing member, for charging the image bearing member with a peripheral velocity difference between the charging member and the image bearing member, and a controller for variably controlling the peripheral velocity difference at the time when an area which becomes an image forming area of the image bearing member is charged by the charge member.

Abstract: An image forming apparatus includes an image bearing member and a charging member in proximity or in contact with the image bearing member. A frequency of an oscillating voltage is a first frequency when a peripheral speed of the image bearing member is a first peripheral speed, and the frequency of the oscillating voltage is a second frequency when the peripheral speed of the image bearing member is a second peripheral speed. A 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 first, second and third alternating currents flowing in the charging member in use of the first peripheral speed and the first frequency. The determined peak-to-peak voltages are applied to the charging member.

Abstract: An image forming apparatus including a photosensitive member that holds an image formed by a developing agent, a charging device that charges a surface of the photosensitive member, a voltage applying device that applies a voltage to the charging device, a first cleaning element that contacts the surface of the photosensitive member, a second cleaning element that contacts a surface of the first cleaning member, and a first voltage controlling device, connected to the charging device, the first cleaning element and the second cleaning element, that generates a predetermined potential difference between the first cleaning element and the second cleaning element based on the voltage applied to the charging device.

Abstract: An image forming apparatus includes a process cartridge detachably mountable with respect to the main body of the apparatus. The process cartridge is provided with an image bearing member, a charger for charging the image bearing member, a power supply for applying an alternating current voltage to the charger, and a controller for variably controlling the alternating current supplied from the power supply to the charger in conformity with information about the use situation of the process cartridge. The process cartridge can also include an image bearing member, a charger for charging the image bearing member, the charger permitting an alternating current voltage to be applied thereto by a power supply, and a memory for storing therein information about the use situation of the process cartridge, and information of a plurality of preset control values for an alternating current supplied from the power supply to the charger to be variably controlled in conformity with the information.

Abstract: An image forming apparatus includes a flexible charging member, which forms a nip portion between itself and an image bearing member. The charging member charges the image bearing member and is applied with a voltage when the charging member at least charges the image bearing member for an image formation. The nip portion is provided with an electrically conductive particles developing device for developing an electrostatic image formed on the image bearing member with a developer. The developing device executes a developing operation and, at the same time, executes a collecting operation for collecting a residual developer on the image bearing member.

Abstract: A method of compensating for image quality controls a tone reproduction curve (TRC). The toner reproduction curve TRC &phgr;(k) measured by a color toner density sensor is compared with a target TRC &phgr;R to obtain a deviation &Dgr;&phgr;. A variation &Dgr;VB of a developer bias VB is calculated from a Jacobian matrix (JB) of a measured developer bias VB to calculate a new developer bias VBN and determining a measured grid voltage VG as a new grid voltage VGN if the deviation (&Dgr;&phgr;) is greater than a tolerance &Dgr;&phgr;T. A backplating vector VBP is obtained from the grid voltage VGN and the developer bias VBN. The backplating vector VBP is compared with a critical value VT to set control parameters VGN and VBN and control the TRC &phgr;. Thus, noise effects on the image quality are minimized to provide an output image closest to an input image quality so as to improve the image quality.

Abstract: An image forming apparatus includes an image bearing member, a flexible changing member and a developing device. When a first area to be an image forming area of the image bearing member, is present in a nip portion, a superimposed voltage resulting from a direct current voltage and an alternating voltage having a peak to peak voltage smaller than an alternating voltage applied when a charging potential of the image bearing member is converged is applied to the charging member. When a part of a second area to be a non-image area of the image bearing member exists in the nip portion, a direct current voltage without an alternating voltage is applied to the charging member.

Abstract: In a printer with an electrically chargeable image drum, such as a laser or a LED printer, for imprinting a medium by transferring toner to the medium, including, arranged around the image drum, a charging unit, a writing unit and a toner unit, the toner unit is disposed at a predetermined angular distance from the charging unit and a sensor is disposed at essentially the same angular distance from the charging unit to determine the charge of the image unit at the toner location for adjusting the voltage of at least one of the charging unit and the toner unit depending on the charge voltage of the image drum as determined by the sensor.

Abstract: A charger has a cylindrical rotation tube coming in contact with an image receptor on which a toner image is formed, the rotation tube to which a predetermined charge bias is applied, and drive means for driving the rotation tube at a predetermined peripheral speed, the charger for uniformly charging the surface of the image receptor. When the peripheral speed of the image receptor is V1 and the peripheral speed of the rotation tube is V2, the following relation is satisfied: 1.01<(V2/V1)≦1.10.

Abstract: A parameter which is a function of ionization voltage of a first ionization device is displayed and/or used to control the ionization voltage of a second ionization device in accordance with altitude, pressure, or humidity. The first device can be a DC ionization device, e.g., a scorotron, while the second device can be an AC ionization device, e.g., a discorotron or a dicorotron. A third ionization device can also have its ionization voltage controlled by the first device ionization voltage. The invention can be used in a xerographic apparatus.

Abstract: An image forming apparatus includes an image bearing member; a charger for electrically charging the image bearing member; an electrostatic image forming device for forming an electrostatic image by selectively discharging a surface of the charged image bearing member; a developer for developing the electrostatic image formed on the image bearing member into a toner image; a transfer device for transferring the toner image from the image bearing member onto a transfer material; wherein the charger is capable of collecting residual toner from the image bearing member after an image transfer operation; an electric field forming device forms an electric field between the charger and the image bearing member to transfer the toner in the charger to the image bearing member; and a controller controls a length of time during which the electric field forming device forms the electric field, wherein the controller controls the length of time substantially in accordance with wear of a surface of the image bearing membe

Abstract: In a method for forming an image, an electrification device electrifies an image bearing member to a predetermined potential. An exposure device exposes the electrified image bearing member. A potential detection device detects the potential of the electrified image bearing member and the image bearing member is re-electrified using the electrification device in accordance with a value obtained on the basis of the detected potential. The potential of the re-electrified image bearing member is detected. A value to be applied to the electrification device is determined on the basis of both the detected potential and the redetected potential when a difference between the redetected potential and a target value is great. An image is formed by electrifying the image bearing member in accordance with the determined value.

Abstract: The present invention employs a thickness detecting mechanism including a system for emitting polarized light and a reception system for receiving reflected light and generating electric signals. By use of this thickness detecting mechanism, the thickness of a toner layer attached to a latent image is measured. Developing conditions are controlled in relation to the measured thickness.

Abstract: A logic and control unit (LCU) is configured to assess the viability of various subsystems in the electrophotographic marking process. The LCU determines a charging efficiency between a primary charger and a photoconductor, establishes a reference voltage on the photoconductor, wherein the reference voltage corresponds to the charging efficiency, operates a first subsystem in a non-print production mode to produce a first resulting voltage on the photoconductor, and translates the photoconductor to a stationary sensor for measuring the first resulting voltage.

Abstract: In an image forming apparatus, in accordance with formation of paper, there are controlled parameters; that is, a color conversion parameter pertaining to a color conversion section 23 of a drawing section 22; a parameter pertaining to a correction curve of an TRC·&ggr; correction section 24 or a parameter pertaining to the number of screens or a growth pattern of a screen processing section 25 provided in a printer engine control section 12; parameters for use in adjusting electrification, exposure, and a voltage to be used during a developing operation, which are employed in a printer engine 13; a parameter for adjusting a voltage or current during a transfer operation; and a parameter for adjusting a fixing temperature or pressure. Parameters are controlled so as to reduce inconsistencies, which would otherwise arise in paper of poor formation. Thus, picture quality of an image is improved while inconsistencies are made less noticeable.

Abstract: A control circuit of a digital copying machine sets a total current to a charger at a high level in a printing operation, sets the total current to the charger at a low level when turn-off of power to the digital copying machine has been instructed to initiate a finishing operation, and turns off the total current to the charger when the finishing operation has been completed.

Abstract: An electrophotographic printer maintains a surface potential of a photosensitive drum at a constant value even when a photosensitive layer corresponding to a surface of the photosensitive drum wears down. The electrophotographic printer includes a charging power supply 3, a charging roller 1, a photosensitive drum 2, a discharge unit 11, a charging current detection unit 4, a transfer power supply 9, a transfer roller 8, a transfer current detection unit 14, an arithmetic and control unit 12, and a memory unit 13.

Abstract: An image forming apparatus includes an image bearing member and a charge member for electrically charging the image bearing member while contacting the image bearing member. An oscillating voltage, including a component of AC voltage, is applied to the charge member. A first detector detects an average of the AC current applied to the charge member. A second detector detects a value of the AC current corresponding to a peak of the AC voltage. A controller effects control such that when a detected current value is smaller than a first predetermined value, the detected current value of the first detector is at the first predetermined value, and when the detected current value of the first detector is larger than the first predetermined value, a current value of the second detector is at a second predetermined value.

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), the charging device positioned in a non-contact state with the surface of the image carrier.

Abstract: An electrophotographic device includes a control section configured to control operations of a charging unit, an exposure unit, and other units to satisfy a desired condition.

Abstract: An image forming apparatus includes an image bearing member; an electrostatic image forming unit for forming an electrostatic image on said image bearing member, the electrostatic image forming unit including a flexible charge member for electrically charging the image bearing member, the charge member forming a nip between the image bearing member and itself and is supplied with an oscillating voltage, wherein electroconductive particles are provided in the nip; and a developing unit for developing an electrostatic image formed on the image bearing member with a developer, the developing unit being capable of a residual developer on the image bearing member, wherein a frequency f (cycle/sec) of the oscillating voltage and a peripheral speed v (mm/sec) of the image bearing member satisfy |f/v|≧12 (cycle/mm).

Abstract: An electrophotographic printer maintains a surface potential of a photosensitive drum at a constant value even when a photosensitive layer corresponding to a surface of the photosensitive drum wears down. The electrophotographic printer includes a charging power supply, a charging roller, a photosensitive drum, an erasing unit, a charging current observation unit, an arithmetic and control unit, and a memory unit. The arithmetic and control unit rotates the photosensitive drum a plurality of times while the erasing unit is turned off during an initial operation of the electrophotographic printer, controls the charging power supply to generate a charging voltage, adds values of the charging current while the photosensitive drum rotates a plurality of times, and stores a result of an addition of the values in the memory unit.

Abstract: A new charging member which is durable enough to exhibit stable performance over a long period of time without deterioration by the sticking of toner particles. It is characterized by its surface having a universal hardness no higher than 10 N/mm2 at a depth equivalent to the diameter of toner particles.

Abstract: The voltage value or frequency of an AC voltage component applied to charging rollers in a mono-colored black image forming mode is reduced so as to be smaller than the value or frequency applied in the full-colored image forming mode. In this manner, in the mono-colored black image forming mode, electric discharge between the charging rollers and photosensitive drums which does not form images is reduced, so that a shaving-off phenomenon on the surfaces of the photosensitive drums can be decrease, thereby increasing a lifespan of the photosensitive drums.

Abstract: An image forming apparatus has an image forming device for forming an image on a recording material, a storing device for storing a parameter regarding an accumulation operation amount of the image forming apparatus, and a changing device for changing an image forming condition of the image forming device in accordance with the parameter.

Abstract: An image forming apparatus includes an image bearing member and a charge member contacted to the image bearing member for electrically charging the image bearing member. An oscillating voltage including an AC voltage component is applied to the charge member. A first detector detects an AC current applied to the charge member and a second detector detects the AC current corresponding to a peak or a neighborhood of the peak of the AC voltage. A controller effects control such that current detected by the second detector is a predetermined level when the current detected by the first detector is within a predetermined range, and such that current detected by the first detector is a predetermined level when the current detected by the first detector is outside the predetermined range.

Abstract: The surface of an electrostatic recording member in an electrophotographic recording apparatus is charged to a standard primary charge V0s. The standard primary charge on the recording member is then modulated using a first test exposure E1 to form a first exposed test area, and using a second test exposure E2 to form a second exposed test area. A first test surface potential V1 is measured in the first exposed test area and a second test surface potential V2 is measured in the second exposed test area. A measured intrinsic sensitivity bm associated with the recording member is calculated using V1 and V2. A measured intrinsic toe dm associated with the recording member also is calculated using V1 and V2. A corrective charge parameter V0i is calculated using dm, and a corrective exposure parameter E0l is calculated using bm and dm. V0 is then adjusted to equal V0i, and E0 is adjusted to equal E0i.

Abstract: A control circuit of a digital copying machine sets a total current to a charger at a high level in a printing operation, sets the total current to the charger at a low level when turn-off of power to the digital copying machine has been instructed to initiate a finishing operation, and turns off the total current to the charger when the finishing operation has been completed.

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 including image forming means for forming an image on a recording material, wherein at least a part of the image forming means is in the form of a unit which is detachably mountable to a main assembly of the apparatus, said apparatus includes memory, wherein said memory is mounted to said unit, wherein said memory stores information relating to timing at which a driving parameter of said image forming means.

Abstract: An image forming apparatus including image forming means for forming an image on a recording material, wherein at least a part of the image forming means is in the form of a unit which is detachably mountable to a main assembly of the apparatus, said apparatus includes memory, wherein said memory is mounted to said unit, wherein said memory stores information relating to timing at which a driving parameter of said image forming means.

Abstract: A process cartridge detachably mountable to a main body of an image forming apparatus, includes 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 a storage device for storing information concerning the type of the charging member.

Abstract: An image forming apparatus with an image bearing member and a charging member for contactably charging the image bearing member. The charging member is provided within an exchangeable unit. An electric power containing an AC component is applied to the charging member, and adjustments are made to the magnitude of the AC component. When the exchangeable unit is exchanged, the magnitude of the AC component is returned to an initial value thereof, so as to extend the life of the image bearing member in situations where the exchangeable unit is exchanged and the AC component might otherwise have a magnitude inappropriate for the new unit.

Abstract: An image forming apparatus includes an image bearing member; image forming means for forming an image on the image bearing member, the image forming means including charging means for electrically charging the image bearing member; optical discharging means for electrically discharging the surface of the image bearing member, wherein a charging operation of the charging means is started at the time when a neighborhood of a leading end of an area discharged by the optical discharging means after start of rotation of the image bearing member is substantially opposed to the charging means.

Abstract: An apparatus and method are described for extending the life of a photoreceptor in xerographic printing. At a predetermined point in the life span of a photoreceptor, a correction circuit is interposed between the power supply and the charging device of the printer. Correction circuits of different designs can be selected to compensate for the photoreceptor properties at different stages of its useful life. The different correction circuits can be automatically activated over time, or can be retrofitted into a replaceable module when the replaceable module is remanufactured.

Abstract: An image forming apparatus including a photoconductive member, a charging mechanism, an optical writing mechanism, a development mechanism, a sensing mechanism, and a controlling mechanism. The charging mechanism charges a surface of the photoconductive member at a charge voltage. The optical writing mechanism writes latent images including first and second latent images on the surface of the photoconductive member. The development mechanism develops the first latent image into a first toner pattern at a solid toner density and the second latent image into a second toner pattern at a half-tone tone density. The sensing mechanism detects reflection densities of the first and second toner patterns and generates output signals representing detection results detected by the sensing mechanism. The controlling mechanism adjusts values of the solid toner density, the charge voltage, and the half-tone toner density based on the output signals.

Abstract: An image forming apparatus includes an image bearing member and an electrostatic image forming unit including an electrification device, which is disposed in contact with the image bearing member at an electrification location for performing injection electrification of the image bearing member. The apparatus is configured to change a peripheral speed difference between the electrification device and the image bearing member in accordance with a first period when an area of said image bearing member, which is to be an image forming area, is present in the electrification position; and a second period in which at least a particle of an area of said image bearing member, the area being a no-image area is present in the electrification position. The peripheral speed in the second period is smaller than the peripheral speed in the first period.

Abstract: An image forming apparatus includes an image bearing member; a charging member, contactable to the image bearing member, for electrically charging the image bearing member at a charging position; developing means for developing an electrostatic image formed on the image bearing member with a developer; wherein when a first area on the image bearing member which is going to be an image formation area is at the charging position, the charging member moves with a peripheral speed difference relative to the image bearing member, and when a second area on the image bearing member which is a part of an area which is going to be a non-image formation area is at the charging position, the charging member moves substantially without a peripheral speed difference relative to the image bearing member, and wherein a collecting electric field is formed for collecting the developer from the second area to the developing means.

Abstract: In an image forming apparatus, an image bearing member bears an electrostatic image. An electrification device electrifies the image bearing member to a predetermined potential. An exposure device exposes the image bearing member electrified by the electrification device to an image. A potential detection device detects the potential of the image bearing member. A determination device performs calculation using a control coefficient for the potential detected by the potential detection device, and determines an electrification bias value. The determination device corrects the control coefficient to determine an electrification bias when the detected potential upon electrification at the electrification bias obtained by calculation falls outside a predetermined range.

Abstract: Method and system for predicting print quality degradation in an image forming device. Correction factors produced during calibration cycles are stored for future analysis. The correction factors, or alternatively 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: An image forming method and apparatus, wherein the charging amount that a charging device charges a photosensitive drum is controlled so as to reduce the charging amount in a period, except for the image forming period, than that during the image forming period. While the charging amount is reduced, the voltage applied to the charging device is controlled by chopping. Accordingly, mote adhesion onto the charging device and improper chopping can be effectively prevented or reduced. When print data is input from an outside source, the quantity of airflow generated by the fan is allowed to increase, and the printing operation starts after the quantity of airflow is increased. As sufficient airflow is generated inside the laser printer before the charging device starts to charge, motes and other objects existing in the laser printer can be ejected outside effectively. As a result, mote adhesion onto the charging device and improper charging can be prevented or reduced.

Abstract: An image forming apparatus is provided which includes an image bearing member, an electrifying member for electrifying the image bearing member; an image forming member for forming an image on the image bearing member electrified by the electrifying member; a conveying member for making a recording material, which has been conveyed from a recording material receiving portion, wait and then conveying the image on the image bearing member to a transfer portion for transferring the image onto the recording material; and a control member for controlling electrification start timing by the electrifying member in accordance with start timing of conveyance of the recording material by the conveying member. With the above structure, consumption power necessary for electrification of the image bearing member can be reduced as much as possible, and further, the service life of the image bearing member can be improved.

Abstract: An object of the present invention is to provide an image forming apparatus in which when a first area to be an image forming area of the image bearing member exists in said nip portion, a superimposed voltage resulting from a direct current voltage and an alternating voltage having a peak to peak voltage smaller than an alternating voltage applied when a charging potential of the image bearing member is converged is applied to the charging member, and wherein when a part of a second area to be a non-image area of the image bearing member exists in said nip portion, a direct current voltage without an alternating voltage is applied to the charging member.

Abstract: An image forming apparatus of the present invention includes a particle conveying body made up of a light-transmitting conductive layer, an insulative'screen provided on the conductive layer and formed with a number of pores, and a screen electrode formed on the screen. Photoconductive, colored particles are charged to negative polarity and then caused to fill the pores by an electric field. When the particles in the pores are exposed via the conductive layer, electron-hole pairs are generated in the particles. An electric field of as high as 104 V/cm or above is formed between the conductive layer and the screen electrode and separates the electrons and holes. The electrons leak to the conductive layer and cause the particles to be charged to positive polarity. An electric field formed between a facing electrode positioned behind a recording medium and the conductive layer causes the particles to fly toward and deposit on the medium.

Abstract: While a first cleaning bias (600 V) is applied to a cleaning roller, a bias applied to a transfer roller is switched between a second transfer bias and a first transfer bias. The surface potential of a photosensitive drum changes depending on the bias applied to the transfer roller. When the photosensitive drum contacts the transfer roller while the second transfer bias is applied to the transfer roller, the surface potential of the photosensitive drum becomes the second surface potential (approximately 900-1000 V). When the photosensitive drum having the second surface potential contacts the cleaning roller, the cleaning roller collects toner remaining on the photosensitive drum. When the photosensitive drum contacts the transfer roller while the first transfer bias is applied to the transfer roller, the surface potential of the photosensitive drum becomes the first surface potential (approximately 200-400 V).