Abstract: A printer including a body, a developer cartridge, and a developer level sensor. The body includes a printing unit to print an image on a print medium based on electrophotography. The developer cartridge is attachable to the body and includes a developer container including a developer, and a developer outlet provided at a length-direction side of the developer container to supply the developer from the developer container to the printing unit. The developer level sensor is installed on the body near the developer outlet to generate an electrical detection signal based on a developer level in the developer container.

Abstract: A printer including a body, a developer cartridge, and a developer level sensor. The body includes a printing unit to print an image on a print medium based on electrophotography. The developer cartridge is attachable to the body and includes a developer container including a developer, and a developer outlet provided at a length-direction side of the developer container to supply the developer from the developer container to the printing unit. The developer level sensor is installed on the body near the developer outlet to generate an electrical detection signal based on a developer level of the developer container.

Abstract: A waste container is detachably mounted on an electrophotographic image forming apparatus to electrophotographically print an image by using a developing agent formed by mixing a carrier and a toner and receives therein a waste during the printing. The waste container includes a first inlet through which a first waste is introduced, a second inlet through which a second waste is introduced, a first region in which the first waste is stored, and a second region that is separated from the first region and in which the second waste is stored.

Abstract: Provided is an apparatus and method for supplying a charge voltage to an organic photoconductor (OPC) drum. The apparatus includes a storage unit for storing first service life information of the OPC drum according to a first supplying method, and second service life information of the OPC drum according to a second supplying method, a sensor unit for measuring information about conditions surrounding the apparatus, a control unit for selecting one of the first and second supplying methods according to the measured information and determining a charge voltage corresponding to the service life information according to the selected method, and a voltage supplying unit using the selected method to supply the determined charge voltage to the OPC drum.

Abstract: A waste container is detachably mounted on an electrophotographic image forming apparatus to electrophotographically print an image by using a developing agent formed by mixing a carrier and a toner and receives therein a waste during the printing. The waste container includes a first inlet through which a first waste is introduced, a second inlet through which a second waste is introduced, a first region in which the first waste is stored, and a second region that is separated from the first region and in which the second waste is stored.

Abstract: Provided is an apparatus and method for supplying a charge voltage to an organic photoconductor (OPC) drum. The apparatus includes a storage unit for storing first service life information of the OPC drum according to a first supplying method, and second service life information of the OPC drum according to a second supplying method, a sensor unit for measuring information about conditions surrounding the apparatus, a control unit for selecting one of the first and second supplying methods according to the measured information and determining a charge voltage corresponding to the service life information according to the selected method, and a voltage supplying unit using the selected method to supply the determined charge voltage to the OPC drum.

Abstract: Provided is an apparatus and method for supplying a charge voltage to an organic photoconductor (OPC) drum. The apparatus includes a storage unit for storing first service life information of the OPC drum according to a first supplying method, and second service life information of the OPC drum according to a second supplying method, a sensor unit for measuring information about conditions surrounding the apparatus, a control unit for selecting one of the first and second supplying methods according to the measured information and determining a charge voltage corresponding to the service life information according to the selected method, and a voltage supplying unit using the selected method to supply the determined charge voltage to the OPC drum.

Abstract: A toner density estimating method for a two-component developer is provided. The toner density estimating method includes: sensing photo-reflectance of a test pattern having a plurality of grayscales formed by using toner; calculating a rate of change of the photo-reflectance according to the grayscales of the test pattern; and estimating a toner density based on the rate of change. Accordingly, it is possible to accurately estimate the toner density irrespective of the influence of changes in temperature, humidity, or other external factors.

Abstract: An electrophotographic image forming device is provided which includes an image holder on which an electrostatic latent image is formed. A magnetic roller has a magnetic brush including nonmagnetic toner and a magnetic carrier using a magnetic force. Donor rollers are provided which have toner layers that are received from the magnetic roller on an outer circumference of each of the donor rollers. The donor rollers are located opposite to the image holder to develop the toner onto the electrostatic latent image.

Abstract: A hybrid type developing apparatus and method forms a magnetic brush of non-magnetic toner and a magnetic carrier on a circumference of a magnetic roller forms a uniform toner layer on the circumference of a donor roller using only toner from the magnetic roller, and develops an electrostatic latent image on an image receptor. The hybrid type developing apparatus includes: a plurality of electrodes on the circumference of the donor roller; first and second brush electrodes in an upstream area and a downstream area, respectively, of the donor roller facing the magnetic roller with respect to a direction of rotation; and a bias applying device for applying a recovery bias to the first brush electrode to remove toner from the donor roller and a supply bias to the second brush electrode to supply toner from the magnetic roller to the donor roller.

Abstract: An apparatus and method for cleaning a transfer roller of a wet-type image forming apparatus are provided. The method includes applying a measured voltage to the transfer roller; measuring a resistance among a transfer backup roller, an intermediate transfer medium, and the transfer roller based on the applied measured voltage; calculating a density of a toner of a developer on the transfer roller based on the measured resistance; and if the density of the toner is more than or equal to a predetermined reference value, supplying a carrier or applying the cleaning voltage. Thus, the cleaning voltage can be adjusted depending on the density of the toner of the developer on the transfer roller so as to maintain appropriate cleaning efficiency. If the density of the toner is greater than or equal to the predetermined reference value, the carrier can be supplied so as to improve the cleaning efficiency.

Abstract: An image forming apparatus is provided that forms an image with liquid developer, and a method thereof. The image forming apparatus includes a plurality of photoconductors on which developer images having carrier rates different from each other are formed with corresponding liquid developers. An image transfer member is disposed to form transfer nips with the respective photoconductors in such a manner that the developer images of the respective photoconductors are overlappingly transferred onto the image transfer member according to a transfer order predetermined on the basis of the carrier rates thereof. The developer images from the respective photoconductors are moved to an image receiving medium.

Abstract: An image forming apparatus includes an image forming part that forms an image on a recording medium and includes a plurality of photoconductors, a plurality of charging parts that charges the photoconductors, a plurality of developing parts that develops the charged photoconductors, and a plurality of static electricity erasing parts that erases surface potentials of the charged photoconductors. A power supplying part supplies power to the image forming part, and a controller controls to switch the operation of the static electricity erasing parts independently and controls the image forming part to form the image on the recording medium if power applied to the respective photoconductors through the charging parts and the developing parts reaches a target value.

Abstract: An image transfer member, an image transfer device and an image forming system employing the image transfer member and device are disclosed. The image transfer member comprises a base layer, and a surface layer formed from a semi-conductive material above the base layer to receive the developer image transferred from the photoconductor. The surface layer forms a contact inscribed angle ? in the range of 10° to 50° between the surface thereof and the developer image. The image transfer member has a voltage-current characteristic exhibiting a current density (CD) in the range of 0.6 ?A/cm2?CD?1.5 ?A/cm2 at 1 KV voltage, and a voltage decay characteristic exhibiting a voltage decay time (DT) in the range of 0.4 sec?DT?3 sec for the voltage decay from 500 V to 100 V. The present invention avoids a transfer defect such as transfer void produced by breakdown caused when a high bias voltage is applied to a developer image having a high electric charge and to significantly improve the transfer efficiency.

Abstract: An image forming apparatus for performing a printing job using an intermediate transfer belt is provided. The image forming apparatus has a voltage determination part for determining a predetermined level of a refresh charge corresponding to a potential difference which is generated on opposite surfaces of the intermediate transfer belt, and a power supply for supplying the refresh charge to the intermediate transfer belt so that the potential difference is offset. The power supply supplies the refresh charge to the intermediate transfer belt through a certain roller which is in contact with the intermediate transfer belt. Accordingly, the potential difference caused by the polarization in the intermediate transfer belt is offset by the refresh charge, and the variation of the resistance caused by the potential difference is prevented.

Abstract: A toner density estimating method for a two-component developer is provided. The toner density estimating method includes: sensing photo-reflectance of a test pattern having a plurality of grayscales formed by using toner; calculating a rate of change of the photo-reflectance according to the grayscales of the test pattern; and estimating a toner density based on the rate of change. Accordingly, it is possible to accurately estimate the toner density irrespective of the influence of changes in temperature, humidity, or other external factors.

Abstract: There are provided a hybrid type developing apparatus and method.

Abstract: An electrophotographic image forming apparatus includes: an image receptor on which an electrostatic latent image is formed; a magnetic roller for forming a magnetic brush having a non-magnetic toner and a magnetic carrier by magnetic force; a donor roller facing the image receptor and receiving a toner from the magnetic roller to form a toner layer on an outer circumference thereof; bias applying device for applying a bias voltage to the donor roller to develop the electrostatic latent image by supplying the toner from the toner layer; and toner removing device which contacts the donor roller and removes at least a portion of the toner layer from a surface of the donor roller after developing. A method of developing the latent image on the image receptor is provided by the apparatus.

Abstract: A hybrid type developing apparatus of an electrophotographic image forming apparatus includes: an image receptor on which an electrostatic latent image is formed; a magnetic roller for forming a magnetic brush of non-magnetic toner and magnetic carrier by using magnetic force; a donor roller which faces the image receptor and has a circumference for supporting a toner layer formed by receiving toner from the magnetic roller; a bias voltage applying device for applying a development bias voltage to the donor roller to develop toner of the toner layer to the electrostatic latent image; an electrode positioned at an upstream side at a point closest and most adjacent position between the donor roller and the image receptor and at a downstream side at a point closest and most adjacent position between the donor roller and the magnetic roller and an applied bias voltage of weakening adhesive force of the toner layer to the donor roller and cohesive force of toner to each other.

Abstract: An electrophotographic image forming apparatus is provided which includes a first developing unit which forms a monochrome image in a two-component development method and includes a photosensitive medium on which an electrostatic latent image is formed by a first exposure unit. Additionally, a plurality of second developing units are provided which form a color image in a one-component development method and include a photosensitive medium on which an electrostatic latent image is formed by a second exposure unit. A control unit generates control signals to independently control the operations of the first and second exposure units and the first and second developing units.