Abstract: An electrophotographic apparatus and a process cartridge have a charge unit for charging the surface of a photosensitive member by direct injection of electrical charge from a contact charging member to the photosensitive member. The charging unit also functions as a unit for supporting residual toner on the surface of the photosensitive member after transfer, for normalizing the electrical charge of the residual toner, and for returning the normalized residual toner to the surface of the photosensitive member. A developing unit also functions as a unit for recovering the normalized residual toner returned to the surface of the photosensitive member. The absolute value of the difference in charged potential between a first rotation and a second rotation of the photosensitive member is higher than 5 V and lower than 70 V.

Abstract: An image forming device which is capable of preventing generation of toner filming and obtaining a stable image quality without defects over a long period and which is environmentally friendly. The image forming device, for forming an image with a spherical toner, comprises image holding members, contact type charging means, exposing means, developing means and transfer means. A toner shape change ratio (Tt) of deformed toner particles passed between the contacting portions of the image holding members and the charging means is in a range of 50 to 100 percent.

Abstract: In order to solve the problem, there is provided a charging device having: a roll-like charging member disposed in contact with a surface of a member to be charged and for charging the surface of the member to be charged; wherein: the charging member includes a conductive substrate, and at least an elastic layer and a surface layer applied sequentially onto a surface of the conductive substrate; and opposite end portions of the surface layer axially project beyond opposite end portions of the elastic layer respectively, while the opposite end portions of the surface layer are made to cover the elastic layer and made open.

Abstract: An image forming apparatus and a process cartridge capable of satisfying both a high quality image and an excellent maintenance property with a simple configuration. A photosensitive member and a charging roller that is a member rotating in contact with the photosensitive member are brought into contact with each other in the image forming process. When an image forming operation starts from a standstill, the charging roller is rotated before the photosensitive member starts to be rotated. Furthermore, before the photosensitive member stars to be rotated, a reversed bias voltage that is a voltage opposite to the bias voltage at usual development time is applied between the members rotating in contact with the photosensitive member and the photosensitive member. The time for which the charging roller is rotated before the photosensitive member starts to be rotated is set to be 0.01-2.

Abstract: An electrophotographic drum-shaped photoconductor has an electroconductive support and a photoconductive layer formed thereon, with a lubricating material being applied to the surface thereof in the shape of a plurality of bands spaced therebetween, constituting band-shaped lubricating material applied areas, extending along a circumference of the drum-shaped photoconductor in the direction perpendicular or substantially perpendicular to an axis of rotation of the drum-shaped photoconductor. An electrophotographic image formation method and an image forming apparatus employing the above-mentioned drum-shaped photoconductor are also disclosed.

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: A bracket to mount a charge roller and a blade against a photoconductive drum within an image forming apparatus. Bracket may comprise a pair of guides that extend outward to receive the ends of the charge roller. A biasing device may be positioned to bias the charge roller against the photoconductive drum. The guides may include an opening sized to allow the charge roller to move and maintain contact with the photoconductive drum. A mounting surface may be positioned on the bracket for receiving adhesive to mount the blade. In one embodiment, the bracket is constructed of an electrically conductive material such that a charge introduced to the bracket is delivered to the charge roller.

Abstract: A charging member is provided, in which the electrical resistance is controlled with ease, the electrical resistances are uniform, and the electrical resistance, chemical properties, mechanical properties, etc., are suppressed to change with time so as to exhibit superior durability. The charging member primarily contains 100 parts by weight of at least one kind of polar rubber including at least a nitrile rubber, and further contains at least 0.01 parts by weight or more and 5 parts by weight or less of diazabicycloamine compound and 0.01 parts by weight or more and 10 parts by weight or less of weakly acidic compound.

Abstract: A charge roller that includes a metal core, an elastic member configured wrapped around the metal core, and film members is disclosed. Each of the film members is wrapped around each end of the elastic member in a circumferential direction of the metal core such that at least a part of each of the film members exists at every position around the ends of the elastic member in an axial direction of the metal core. Portions of the film members do not overlap each other in an radial direction of the metal core.

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: A charging device, suitable for use in an electrophotographic image forming apparatus, is formed of an object to be charged, and a roller-shaped charging member disposed in contact with the object via electroconductive particles and supplied with a voltage to charge the objects. The charging member has a surface layer including an elastic foam and is moved with a surface speed difference relative to the object. The charging member has surface cavities having an average diameter of 5 to 150 &mgr;m and occupying an area percentage of 50 to 90%. An image forming apparatus and a process cartridge therefor including the charging device are also provided.

Abstract: A charging device is provided. The charging device comprises a charging member having two spacers made of tape, and the charging member is pressed to contact with the non-image forming region of an image supporter. The surface of the charging member between the spacers is opposite to the surface of the image supporter by a tiny gap. A charging voltage is then applied to the charging member to charge the image supporter. As the image supporter rotates, a large variation of the tiny gap can be avoided. The pressing force of the spacers against the image supporter is set at 4N to 25 N (Newton), and in a moving direction of the surface of the supporter, a contact width of a contact portion where the spacer is pressed to contact with the image supporter is set below 0.5 mm.

Abstract: A charging device for electrically charging a member to be charged includes charging particles including electroconductive particles having particles diameters in the range of 10 nm-10 &mgr;m; and a charging particles carrying member, which has a nip with the member to be charged forming a nip with said member to be charged, for carrying the charging particle to the nip; wherein said charging particles have resistances in the range of 10−1-1012 &OHgr;cm; wherein (an amount, per unit area, of said charging particles carried by said charging particles carrying member)/(an average roughness Ra of a surface of said charging particles carrying member) is in the range of 0.005-1 mg/cm2/&mgr;m.

Abstract: A charge roller that includes a metal core, an elastic member configured wrapped around the metal core, and film members is disclosed. Each of the film members is wrapped around each end of the elastic member in a circumferential direction of the metal core such that at least a part of each of the film members exists at every position around the ends of the elastic member in an axial direction of the metal core. Portions of the film members do not overlap each other in an radial direction of the metal core.

Abstract: A charging device includes a charging rotary member provided in contact with an image bearing member capable of bearing a toner for charging the image bearing member, in which a peripheral speed of the charging rotary member is different from a peripheral speed of the image bearing member, and the charging rotary member includes a surface layer frictionally charging the toner to a normal charging polarity.

Abstract: An OPC 2, a charger 9, a cleaner 10 for cleaning the charger 9, a holder 11 for holding the charger 9, a support frame 12 for supporting the holder 11, a pair of springs 13 and 14 and a driver 15 for driving the holder are accommodated in a single process cartridge 8. The cleaner 10 can be brought into contact with the charger 9 and separated from the same. The driver 15 moves the cleaner 10 between a position of contact at which the cleaner 10 is brought into contact with the charger 9 and a position of separation at which the cleaner 10 is separated from the charger 9. The charger 9 has a wettability that is lower than that of a photosensitive member on which an electrostatic latent image is formed.

Abstract: An image forming apparatus includes a movable image bearing member, a charger means including a charge member for electrically charging the image bearing member with electroconductive particles between the charge member and the image bearing member and a developing member for developing a latent image with toner mixed with electroconductive particles. The latent image is formed on the image bearing member having been charged by the charging means, and a toner image provided by development of the latent image by the developing member is transferred onto a recording material. The electroconductive particles mixed in the toner is carried by the image bearing member and are fed to between the charge member and the image bearing member.

Abstract: The present invention discloses: (1) an electrically conductive member including: a cylindrical base body; and electrically conductive powder sealed inside of the cylindrical base body in a substantially flowable state, or (2) an electrically conductive member including: a cylindrical base body; and electrically conductive powder sealed inside of the cylindrical base body so as not to completely fill the inner volume thereof, or (3) an electrically conductive member including: a cylindrical base body; and electrically conductive powder sealed inside of the cylindrical base body so as to fill only from 20 to 95 % of the inner volume thereof. Moreover, the present invention discloses an image forming apparatus equipped with any of the electrically conductive members.

Abstract: An image forming apparatus includes an image bearing member and a charging device for charging the image bearing member. An electrostatic image forming device selectively removes charges on the image bearing member charged by the charging device to form an electrostatic image. A developing device develops the electrostatic image with toner as a toner image. The toner image on the image bearing member is transferred by a transfer device onto a transfer material. The charging device temporarily collects residual toner after transferring the toner image. A return bias applying device applies a return bias for returning the toner collected in the charging device to the image bearing member in a nonimage forming period. The length of a return bias applying time period of the return bias applying device is variably controlled by a controller.

Abstract: A bracket to mount a charge roller and a blade against a photoconductive drum within an image forming apparatus. Bracket may include a pair of guides that extend outward to receive the ends of the charge roller. A biasing device may be positioned to bias the charge roller against the photoconductive drum. The guides may include an opening sized to allow the charge roller to move and maintain contact with the photoconductive drum. A mounting surface may be positioned on the bracket for receiving adhesive to mount the blade. In one embodiment, the bracket is constructed of a molded thermoplastic polymer.

Abstract: An image forming apparatus includes an image bearing member; charging means for electrically charging the image bearing member, the charging means carrying electroconductive particles and having a charging member elastially press-contacted to the image bearing member; image forming means for forming an electrostatic image by selectively dissipating electric charge on the image bearing member charged by the charging means; developing means for developing the electrostatic image on the image bearing member with toner and for supplying the electroconductive particles to the image bearing member, wherein the electroconductive particles supplied by the developing means is carried to a press-contact portion of the charging member to contribution for electric charging of the image bearing member; and changing means for changing a relation between the charging member and a supply position of the electroconductive particles of the developing means.

Abstract: An image forming apparatus including a photoreceptor having an image forming portion; a charging roller having a gap forming member on both ends thereof to form a gap between the photoreceptor and the charging roller and configured to charge the photoreceptor, wherein the gap forming members do not contact the image forming portion, and wherein the relationship t≧2g is satisfied; a light irradiator configured to form a latent image in the image forming portion; an image developer configured to form a toner image on the photoreceptor; and an image transferer configured to transfer the toner image onto a receiving material, wherein g is the gap and t represents a distance between an inside edge of one of the gap forming members and one of the two ends of the image forming portion closer to the inside edge of the gap forming member.

Abstract: A charging member 2a of a charger 2 is disposed under the effect of a magnetic field produced by a magnetic field production member 4b of a developing device 4 and is made of a nonmagnetic material. The charger 2 comprises the charging member 2a and a removal member 2b disposed in contact with an photoreceptor 1 in the upstream of the charging member 2a, the removal member 2b for removing a deposit on the photoreceptor 1 and the charging member 2a is disposed under the effect of a magnetic field produced by the magnetic field production member 4b of the developing device 4 and is made of a nonmagnetic material. On the other hand, the removal member 2b is disposed under the effect of a magnetic field produced by the magnetic field production member 4b of the developing device 4 and is made of a magnetic material.

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: A charging member for charging a member to be charged, includes an elastic foam member provided at a surface of the charging member, the elastic with wall portion defining the cell portions, wherein gaps connecting said cell portions have areas which are not less than 5% and not more than 50%, for respective cells.

Abstract: A charging member for charging a member to be charged which includes: an electrically conductive member to which a voltage is applicable; and a coating layer that coats the electrically conductive member, in which when a d.c voltage of |10| to |300| (V) is applied to the electrically conductive member, the following relationship is held: Z/Ra is 0.7 or less, where Z is the standard deviation of a resistance of the charging member, and Ra is an average value of the resistance of the charging member.

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: A charging roller is constituted of a shaft, a conductive elastic cylinder, and a charging layer. The shaft is integrally covered with the conductive elastic cylinder. Further, the conductive elastic cylinder is integrally covered with the charging layer. The charging roller formed in this way is restored such that it is loosely encased in a seamless charging tube having semi-conductivity.

Abstract: An electrically semi-conductive roll including a center shaft and a plurality of layers formed radially outwardly of the center shaft, wherein an outermost layer of the plurality of layers which is held in rolling contact with an outer circumferential surface of a photosensitive drum is formed by using a resin composition which contains as a base resin material a fluorine-modified acrylate resin.

Abstract: A charging device includes a rotatable elastic charging roller, contactable to a member to be charged, for electrically charging the member to be charged; DC voltage applying means for applying a DC voltage to the charging roller; wherein the voltage applying means is capable of controlling a width of variation of the DC voltage, the variation being caused by passage of a deformed portion of the charging roller resulting from contact between the member to be charged and the charging roller by a charging region of the charging roller for the member to be charged, to be not more than 1%.

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: 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.

Abstract: An image forming method and apparatus, wherein a surface of a photoconductor is charged with a contact-type charging roller having a surface roughness of 2-40 &mgr;m, and exposed imagewise to form an electrostatic latent image thereon, the latent image being developed with a toner, transferred to a transfer member and fixed, and wherein the toner comprises a colorant, and a binder resin containing a tetrahydrofuran-soluble component having such a molecular weight distribution that at least one peak having a half width not greater than 15,000 is present between 1,000 and 10,000 when measured by gel permeation chromatography.

Abstract: A conductive member which is to be disposed in contact with an electrophotographic photosensitive member and to which a voltage is to be applied; and which includes a support member and a conductive covering layer provided on the support member. The conductive covering layer includes both a first carbon black having a DBP oil absorption of from 300 cm3/100 g to 500 cm3/100 g and a second carbon black having a DBP oil absorption of 250 cm3/100 g or smaller and showing a pH of 5 or below. Also disclosed are a process cartridge and an electrophotographic apparatus which make use of the conductive member as a primary charging roller.

Abstract: To prevent deterioration of charge performance, which is caused by wear of a gap control member that keeps a charge roller into non-contact with the image carrier, the charge roller is brought into contact with a surface of a photosensitive drum via a pair of tape members as the gap control member that contacts with a coat and non-charge portion of the photosensitive drum. A gap G can be formed between an effective charge width portion of the charge roller and the surface of the photosensitive drum.

Abstract: An image forming apparatus includes a charge roller rotatable in contact with the surface of an image carrier to thereby charge the surface. The charged surface of the image carrier is exposed imagewise for forming a latent image. A developing device develops the latent image to thereby form a corresponding toner image. The toner image is transferred to a recording sheet. The charge roller is formed of a core and an elastic body affixed to the periphery of the core. Stearic acid to be added to rubber, which is the major component of the elastic body, is selected to be 1 wt % or less. An AC current value to be applied to the core is selected to be 1.1 mA or less. The image carrier is free from defective charging ascribable to impurities to deposit on the charge roller.

Abstract: A semiconductive roller forming an elastic layer on the outer circumference of a conductive shaft body, in which the elastic layer is an unfoamed body having the addition curing type liquid silicone rubber cured as a base polymer, and the ASKER C hardness of this unfoamed body is 10° to 50°. This semiconductive roller is used as a rotatable developing roller of an image forming apparatus such as a printer.

Abstract: In order to eliminate the cam member, which is mounted to the mounting member side and to which grease is applied, to prevent, as much as possible, the portions to which grease has been applied from becoming exposed to the side of an original placed on the contact glass, an original cover closer is arranged from a mounting member, which has a mounting base and side plates, which are raised from both sides of the mounting base, and has the abovementioned mounting base mounted to the main device unit side, a supporting member, which supports an original cover, has a back plate as well as side plates and a top plate, which are bent from the back plate, and has one end of each of the side plates being rotatably mounted via a hinge pin to the corresponding side plate of the abovementioned mounting member, a cam slider, which is fitted inside the supporting member in a manner enabling sliding towards the side of the abovementioned mounting member, a pressure bearing pin, which is axially mounted between the respect

Abstract: The invention relates to a low tacky, conductive, soft urethane roller for use in a printer. The roller includes a metal salt evenly or homogeneously distributed in a copolymer formed of a diisocyanate, a reactive silicone containing an amine group; and a polyol or a polyamine. The roller can also have a volume resistivity of between about 1E5 ohm-cm and about 5E10 ohm-cm, and includes a metal salt solution in a copolymer formed of a diisocyanate, a reactive silicone containing a hydroxyl group and/or an amine group; and a polyol and/or a polyamine.

Abstract: A method and an apparatus are described for detecting particles on surfaces. Particles are transferred from the surface to be inspected onto a tacky sheet by applying the tacky sheet to the surface and then removing the tacky sheet from the surface. Particles and defects are optically detected on the removed tacky sheet to produce location data. The tacky sheet is selected to leave no residue on the surface to be inspected. The tacky sheet is selected to be compatible with darkfield optical techniques. In one embodiment the tacky sheet is inspected prior applying the tacky sheet to the surface to be inspected, so that particles from the surface are identified as differences between the location data before and after applying the tacky sheet to the surface to be inspected. In one embodiment the tacky sheet is re-applied and reinspected many times before it is replaced.

Abstract: A charging apparatus for use in an image forming apparatus includes a charge roller configured to adjoin to a photoconductive member to provide a charge to a surface of the photoconductive member. The charge roller includes a plurality of roller layers. One of the plurality of roller layers has a resistance ratio with which a roller surface potential is raised by a charge movement. In this case, the resistance ratio has a value such that a time period in which a charge moves within the one of the plurality of roller layers is sufficiently smaller than a time period in which an arbitrary point of the surface of the charge roller moves across a discharge region formed between the charge roller and the photoconductive member.

Abstract: In order to obtain a charging member which is free of problems such as bleeding of a conductive agent and environment dependency, has little voltage dependency, and can be preferably used in a charging system of impressing only a DC voltage, there is provided a charging member comprising an elastic layer, a resistance regulation layer provided on the elastic layer, and a skin layer provided on the resistance regulation layer, wherein the resistance regulation layer is formed by use of a resin composition prepared by blending an ion conductive substance having a molecular weight of 30 to 800 as a conductive agent into a low-resistance resin matrix having a resistance of 1×104 to 1×1010 &OHgr;·cm.

Abstract: A bracket to mount a charge roller and a blade against a photoconductive drum within an image forming apparatus. Bracket may comprise a pair of guides that extend outward to receive the ends of the charge roller. A biasing device may be positioned to bias the charge roller against the photoconductive drum. The guides may include an opening sized to allow the charge roller to move and maintain contact with the photoconductive drum. A mounting surface may be positioned on the bracket for receiving adhesive to mount the blade. In one embodiment, the bracket is constructed of a molded thermoplastic polymer.

Abstract: In an image-forming apparatus having at least i) an electrophotographic photosensitive member having at least a photoconductive layer and a surface layer on a conductive substrate, ii) a developing means having a toner, and iii) a charging means, the photoconductive layer comprises a non-single-crystal material composed chiefly of silicon, the surface layer comprises a non-single-crystal carbon film containing at least hydrogen and has a dynamic hardness in the range of from 4.90×109 to 1.76×1010 Pa (500 to 1,800 kgf/mm2), the charging means has a charging member kept in contact with the electrophotographic photosensitive member, forming a contact zone therewith, charges the electrophotographic photosensitive member electrostatically upon application of a voltage, and the toner is a magnetic toner having toner particles containing at least a binder resin and a magnetic material, and an inorganic fine powder, having an average circularity of from 0.950 to 1.

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: A semiconducting member has a water-soluble polyaniline having an acidic group, and an aqueous polymeric compound. The semiconducting member has a volume resistivity of from 104 &OHgr;·cm to 1012 &OHgr;·cm.

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 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: A nonbleeding bias charging member having an outer layer on a supporting substrate with fluorinated carbon and zinc oxide dispersed in the outer layer material, where bleeding of contaminants to imaging members is decreased or eliminated.

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.