| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 399270000 | Having applied bias | 23 |
| 20080232859 | IMAGE FORMING APPARATUS - An image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D | 09-25-2008 |
| 20080232860 | IMAGE FORMING APPARATUS - An image forming apparatus is provided with a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image formed on the photoconductive member by a first bias, and a magnetic roller for forming a magnetic brush thereon with a two-component developer and forming a thin toner layer on the developing roller by a second bias. If (D | 09-25-2008 |
| 20080310885 | Developing device and image forming apparatus using same - The surface of a developing roller is coated with a phenol resin layer at a higher level in triboelectric series than a toner. A positively charged toner supplied from a magnetic roller onto the developing roller is negatively charged by friction with the phenol resin layer at the higher level in the triboelectric series. As a result, the positive charge of the toner is cancelled out, and the charge amount of toner per unit weight on the developing roller (Q/M)s decreases. Applying this principle, relationship between (Q/M)s and the charge amount of toner per unit weight on the magnetic roller (Q/M)m satisfies (Q/M)s<(Q/M)m. | 12-18-2008 |
| 20090047046 | IMAGE FORMING APPARATUS AND PROCESS CARTRIDGE - An image forming apparatus and process cartridge which uses a two-component developer comprising a toner and a carrier. By using toner and carrier having a small-particle size, deterioration of the toner fluidity over time can be avoided, and further by maintaining stable toner charge even in a low-humidity environment, stable high-quality image formation can be achieved. The occurrence of adherence of carrier to the solid portions of the toner image is reduced in addition to the occurrence of adherence of carrier to the edge portions, and image abnormalities, toner scattering and the like are prevented. | 02-19-2009 |
| 20090190970 | Development Device and Image Forming Apparatus Using the Same - A development device in which abrasion of a developing roller can be reduced to expand the life of the device, and high-speed and high-quality images can be obtained stably over a long time. The developing roller is composed of an elastic body. An intermediate roller made of metal is disposed closely to the developing roller so as to face the developing roller. A magnetic roller is disposed closely to the intermediate roller so as to face the intermediate roller. A developer layer composed of a magnetic carrier and a toner is formed on the surface of the magnetic roller. The developer layer is carried to the intermediate roller side, and only the toner in the developer layer is transferred to the intermediate roller. A toner layer formed thus is transferred from the intermediate roller to the developing roller, and brought into contact with the surface of an image carrying member. | 07-30-2009 |
| 20090245886 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS WITH THE SAME - A first bias Vslv is applied to a development roller | 10-01-2009 |
| 20090304414 | IMAGE FORMING APPARATUS - There is provided an image forming apparatus capable of realizing improvement of an image density by improving dot reproducibility and reducing fog at the same time. An alternating voltage is applied to a development sleeve so that a first period during which a first peak-to-peak voltage Vpp( | 12-10-2009 |
| 20090317142 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS EQUIPPED WITH THE SAME - The present invention provides a developing device that is provided with: a developer containing a toner and a carrier; a first transporting member placed at an opening portion of a developer vessel used for housing the developer; a second transporting member that faces the first transporting member with a first area interposed therebetween, and also faces an electrostatic latent image-supporting member with a second area interposed therebetween; a first electric-field-forming unit that forms a first electric field between the first transporting member and the second transporting member; and a second electric-field-forming unit that forms a second electric field between the second transporting member and the electrostatic latent image-supporting member, and in this structure, the first electric field, formed between the first transporting member and the second transporting member, includes at least an ac electric field, and the second transporting member has a surface that is charged to the same polarity as the charged polarity of the toner when made in friction-contact with the carrier, with a volume resistance value of 1×10 | 12-24-2009 |
| 20090317143 | IMAGE FORMING APPARATUS - There is provided an image forming apparatus capable of realizing Improvement of an image density by improving dot reproducibility and reducing fog as well. An alternating voltage is applied to a development sleeve so that a first period during which a first peak-to-peak voltage Vpp( | 12-24-2009 |
| 20100054820 | IMAGE FORMING APPARATUS - An image forming apparatus includes: a photoconductive drum; a developing roller that is arranged opposite the photoconductive drum and that carries toner; a detecting portion that detects an occurrence of electrical discharge between the developing roller and the photoconductive drum; a control portion that controls the apparatus, that receives an output of the detecting portion and then recognizes the occurrence of the electrical discharge; a direct voltage applying portion that is connected to the developing roller; and an alternating voltage applying portion that, when an electrical discharge detection operation is performed in which the occurrence of the electrical discharge is detected by use of the detecting portion with the alternating voltage applied to the developing roller changed step by step, applies the alternating voltage having a duty ratio and a frequency different from the duty ratio and the frequency for an image forming operation so that the electrical discharge is made to occur simply in a direction in which an increase in current induced by the electrical discharge is smaller for an increase in potential difference, grasped in advance, between the photoconductive drum and the developing roller. | 03-04-2010 |
| 20100209147 | IMAGE FORMING APPARATUS - A duty ratio Du (%), denoted by (T | 08-19-2010 |
| 20110069999 | DEVELOPING DEVICE AND IMAGE-FORMING APPARATUS - A developing device includes: an electric field generating unit that generates an electric field; and a cylindrical developer holder, to which a voltage is applied, that surrounds the electric field generating unit and rotates, the cylindrical developer holder: having an outer circumferential surface having a plurality of grooves that extend in a direction of a rotational axis, the outer circumferential surface being capable of holding developer including a magnetic substance by using the electric field generated by the electric field generation unit, an electrical resistance of an inner wall surface of each of the grooves being higher than an electrical resistance of the magnetic substance included in the developer; and supplying the developer to an image holder that holds an electrostatic latent image. | 03-24-2011 |
| 20110097117 | Image Forming Apparatus - Disclosed is an image forming apparatus, which makes it possible to remove the resistance reduced carriers included in the developer without abandoning normal carriers whose resistances have not reduced, even in mid-course of implementing the image forming operation. The image forming apparatus includes: a carrier adhering roller to make at least a part of carriers, included in the developer, shift and adhere onto a carrier adhering roller in response to an electric field generated between the developer conveyance member and the carrier adhering roller, a recollection roller, rotatably disposed in such a manner that the recollection roller and the carrier adhering roller oppose to each other with a gap between them, to attract carriers, currently adhered onto the carrier adhering roller, onto a circumferential surface of the recollection roller; and a scraping member, contacting the recollection roller, to scrape the adhered carriers off the circumferential surface of the recollection roller. | 04-28-2011 |
| 20120082486 | IMAGE FORMING APPARATUS - An image forming apparatus includes: a developing device that allows a developer to be retained on a developer carrier having a magnet member equipped with a plurality of magnetic poles mounted on an inner periphery thereof and rotates the developer carrier to deliver the developer to an image carrier and that forms a toner image by supplying the toner of the developer to the image carrier by applying a developing bias voltage from a bias voltage source between the developer carrier and the image carrier; a transfer device for transferring the toner image formed on the image carrier to a transfer receiving material; a toner recovery device for recovering the toner remaining on the surface of the image carrier after the transfer of the toner image; and a toner return device for returning to the developing device the toner recovered by the toner recovery device. | 04-05-2012 |
| 20120189357 | DEVELOPMENT DEVICE - A typical configuration of a development device and an image forming apparatus according to the invention includes: a development sleeve and an electrode portion. In the development device, a pre-bias is applied between the electrode portion and the photosensitive drum, a DC voltage is applied to the development sleeve, a development bias is applied between the development sleeve and the photosensitive drum, the toner in the developer on the development sleeve is moved to the photosensitive drum, and an electrostatic latent image is developed on the photosensitive drum. In the development device, electric field intensity between the electrode portion and the development sleeve by the pre-bias is larger than electric field intensity between the image bearing member and the development sleeve by the development bias. | 07-26-2012 |
| 20120251189 | IMAGE FORMING APPARATUS - An image forming apparatus includes a rotating image carrier, a charging device, a latent image forming device, a developing device having a developer holder and developing a latent image as a visible image, a voltage application unit that generates a potential difference between the image carrier and the developer holder to form an electric field, by which toner is directed toward the latent image, in a developing region, and a transfer device that transfers the visible image of the image carrier to a medium, wherein the developer holder having a concavo-convex portion having a convex portion and a concave portion is provided in an outer surface thereof and formed such that the volume resistivity of a portion corresponding to the convex portion is set to be larger than the volume resistivity of a portion corresponding to the concave portion. | 10-04-2012 |
| 20130243494 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - A developing device includes a developer supporting rotator, toner supporting rotator and voltage application unit. The toner supporting rotator is arranged opposite to a developer supporting rotator, supports toner supplied from the developer supporting rotator, and forms a toner layer by a magnetic brush. The voltage application unit causes the toner supported by the toner supporting rotator to an electrostatic latent image on a surface of an image carrier to develop it into a toner image. A longitudinal end portion of the toner supporting side magnetic member is positioned longitudinally more outside than a longitudinal end portion of the developer supporting side magnetic member. A surface of the second rotating sleeve positioned more outside than the end of the developer supporting side magnetic member is composed of a surface of low adherence with lower toner adherence and a higher dielectric constant than those of a surface positioned inside thereof. | 09-19-2013 |
| 20130259538 | IMAGE FORMING APPARATUS - According to one embodiment, an image forming apparatus includes an image bearing member on which an electrostatic latent image is formed by exposure, an exposing device including a plurality of light sources and a plurality of lenses, which are provided along a longitudinal direction of the image bearing member, and configured to radiate light on the image bearing member, and a developing device arranged at a fixed distance apart from the image bearing member and configured to develop, according to application of a direct-current bias, the electrostatic latent image formed on the image bearing member into a visible image using a two-component developer. | 10-03-2013 |
| 20140376973 | IMAGE FORMING APPARATUS - An image forming apparatus can perform a toner collection mode that includes a first positive rotation step in which at the time of no image formation, in a state where the second bias applied to a toner carrying member is set at a higher voltage on the same polarity side as a toner than a first bias, a developer carrying member and the toner carrying member are rotated in the same direction as a direction at the time of image formation and a reverse rotation step in which after the first positive rotation step is performed, in a state where the first bias is set at a higher voltage on the same polarity side as the toner than the second bias, the developer carrying member and the toner carrying member are rotated in a reverse direction to the direction at the time of image formation. | 12-25-2014 |
| 20150037073 | DEVELOPING APPARATUS - A developing apparatus includes a developer carrying sleeve for carrying a developer to a position opposing an image bearing drum, wherein said sleeve is provided with a plurality of groove portions extending in an axial direction of said sleeve; and a developing bias voltage applying device for applying a developing bias voltage to said sleeve, wherein said bias voltage applying device is capable of outputting, as the bias voltage, a voltage of a waveform having a cyclic period including an AC bias portion comprising an AC component and a DC component superimposed thereto, and a blank portion following the AC bias portion and consisting of a DC component, wherein a width L (m) of the groove, a peripheral speed Vs (m/s) of said sleeve, and a duration t1 (s) of the blank portion in one cyclic period of the bias voltage satisfy L/Vs| 02-05-2015 | |
| 20150078788 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS AND PROCESS CARTRIDGE INCORPORATING SAME - A developing device includes a developer bearer to carry, by rotation, developer including toner and magnetic carrier to a development range facing a latent image bearer, and the developer bearer includes a magnetic field generator having multiple magnetic poles and a cylindrical developing sleeve to rotate and bear developer on an outer circumferential face thereof with magnetic force of the magnetic field generator provided inside the developing sleeve. The developing sleeve receives developing bias voltage including an AC component, and includes a base to maintain a cylindrical shape of the developing sleeve and a low friction surface layer including a material lower in friction coefficient with toner than a material of the base. | 03-19-2015 |
| 20150338824 | DEVELOPING DEVICE, AND IMAGE FORMING APPARATUS AND PROCESS CARTRIDGE INCORPORATING SAME - A developing device includes a developer bearer to carry, by rotation, developer including toner and magnetic carrier to a developing range facing a latent image bearer; a casing including a developer container and an opening to expose a part of the developer bearer disposed in the casing; an opposing face of the casing including a conductive material and opposing to a surface of the developer bearer downstream from the developing range in a direction of rotation of the developer bearer; a developing bias source to apply a developing bias to the developer bearer; and an insulation layer disposed on the opposing face of the casing. The opposing face is disposed across, from the developer bearer, a casing gap sized to allow the developer borne on the developer bearer to contact the opposing face. | 11-26-2015 |
| 399271000 | Auxiliary electrode | 1 |
| 20100247164 | DEVELOPING DEVICE - A developing device includes a developing container in which a developer is contained; a developer carrying member for carrying the developer and feeding the developer by rotation thereof to a developing zone in which the developer carrying member opposes an image bearing member on which a latent image is formed and develops the latent image with the developer; and an electrode, disposed opposed to the developer carrying member, to which a bias for forming an electric field for moving regular-charge toner in the developer container toward the developer carrying member is to be applied. The electrode is provided downstream of the developing zone with respect to a rotational direction of the developer carrying member and is provided vertically above the developer carrying member. At least a part of the electrode is located downstream of a rectilinear line connecting a rotation center and top point of the developer carrying member with respect to the rotational direction of the developer carrying member. | 09-30-2010 |
