Abstract: An image forming apparatus includes a photosensitive medium to be charged with a predetermined potential by a charging member, an exposing unit to expose the photosensitive medium to vary a charging level of the photosensitive medium, a developing unit to form an image for one or more colors on the photosensitive medium, a transfer medium to transfer the image from the photosensitive medium, a cleaning unit to clean the transfer medium, and a controller to control an optical power of the exposing unit to be lower than that during forming of the image when a toner band is applied to lubricate at least one of the cleaning unit and the transfer medium.

Abstract: An image forming apparatus and a method to control a velocity ratio thereof. The image forming apparatus includes a developing device to rotate opposite a photoconductive medium and to supply the photoconductive medium with a developer, and a controller to control a velocity ratio of the developing device to the photoconductive medium according to an accumulated number of printed copies.

Abstract: A wet electrophotographic image forming apparatus detects color per print page and executes printing by turning on only the development bias of a developing unit to be used for printing. The wet electrophotographic image forming apparatus has a color detecting unit for detecting colors for developing the electrostatic latent images per print page; and a controller for selectively turning on and turning off development bias applied to developing rollers of the plurality of the developing units according to the colors detected by the color detecting unit.

Abstract: An apparatus to detect the remaining amount of developer in a developing unit is provided. The apparatus includes a light emitting prism and a light receiving prism placed opposite to each other in a developer store space of the developing unit and forming a light emitting path and a light receiving path, respectively. A light emitting element irradiates light through the light emitting prism, and a light receiving element receives a light signal through the light receiving prism. An antistatic agent is coated on a light emitting window of the light emitting prism and a light receiving window of the light receiving prism, respectively, to substantially prevent developer from attaching on the light emitting window and the light receiving window.

Abstract: An image forming apparatus and a method to control a velocity ratio thereof. The image forming apparatus includes a developing device to rotate opposite a photoconductive medium and to supply the photoconductive medium with a developer, and a controller to control a velocity ratio of the developing device to the photoconductive medium according to an accumulated number of printed copies.

Abstract: An image forming apparatus includes a photosensitive medium to be charged with a predetermined potential by a charging member, an exposing unit to expose the photosensitive medium to vary a charging level of the photosensitive medium, a developing unit to form an image for one or more colors on the photosensitive medium, a transfer medium to transfer the image from the photosensitive medium, a cleaning unit to clean the transfer medium, and a controller to control an optical power of the exposing unit to be lower than that during forming of the image when a toner band is applied to lubricate at least one of the cleaning unit and the transfer medium.

Abstract: A belt transfer device prevents the dragging of an image during a transfer process that transfers an image from a photosensitive body onto a transfer belt. The belt transfer device includes a transfer belt that contacts the surface of a photosensitive body, and at least one belt pressing member installed in the front and/or rear of a contact portion (that is, a transfer nip) between the transfer belt and the photosensitive body. The at least one belt pressing member extends the length of the transfer nip, thereby preventing image dragging.

Abstract: A wet-type image forming apparatus and method is provided to sense and maintain a toner concentration level of a developer, and includes a counter for counting the number of dots of input print data, a memory for storing an average coverage of a print medium which corresponds to a predetermined dot number of the print data and storing a lookup table for consumption quantities of carrier and toner which correspond to the average coverage, and a control unit for calculating a toner concentration of a developer that remains in a developer supplying unit by recognizing consumption quantities of the carrier and the toner that are stored in the memory based on the counted dot number.

Abstract: A liquid developing device includes an ink cartridge, a developing container connected to the ink cartridge in which ink is circulated between the developing container and the ink cartridge, a photosensitive body on which an electrostatic latent image is formed, a developing roller facing the photosensitive body, being rotatable to supply the ink to the electrostatic latent image, and a depositing member being installed to maintain a depositing gap between the depositing member and the developing roller and to attach the ink to the developing roller by a potential difference, wherein the developing container includes a first developing container having an outlet opened in a lengthwise direction and an inlet connected to the ink cartridge at a position lower than the outlet, and a second developing container in which ink overflowing from the first developing container via the outlet is stored and which has a drawing hole connected to the ink cartridge, and the ink supplied from the ink cartridge to the first d

Abstract: A charging voltage supply and a method for supplying a charging voltage are provided. The charging voltage supply generates a voltage and branches the generated voltage to at least one charging roller according to voltage applied to a transfer roller. Accordingly, the charging voltage supply can compensate for the charging voltage in view of the reduction of a charging potential of a photosensitive body according to the transfer voltage.

Abstract: An image forming apparatus includes an image-forming unit having a plurality of photosensitive media to be charged; a transfer belt to be rotated along an endless path by a drive roller and a steering roller, an outer surface of the transfer belt being in contact with a surface of each of the plurality of photosensitive media; a transfer voltage applying unit to apply a predetermined transfer voltage to the transfer belt to transfer a toner image formed on the surface of each of the plurality of photosensitive media to the transfer belt by an electrostatic force; and a residual electrical charge removing unit to remove an electrical charge transferred from the plurality of photosensitive media to the transfer belt according to the applied transfer voltage to prevent the electrical charge from being accumulated on the transfer belt.

Abstract: An apparatus to detect the remaining amount of developer in a developing unit is provided. The apparatus includes a light emitting prism and a light receiving prism placed opposite to each other in a developer store space of the developing unit and forming a light emitting path and a light receiving path, respectively. A light emitting element irradiates light through the light emitting prism, and a light receiving element receives a light signal through the light receiving prism. An antistatic agent is coated on a light emitting window of the light emitting prism and a light receiving window of the light receiving prism, respectively, to substantially prevent developer from attaching on the light emitting window and the light receiving window.

Abstract: An image forming apparatus includes at least one photoconductive medium on which an electrostatic latent image is formed; at least one developing device for developing the electrostatic latent image formed on the photoconductive medium with a developer to form a visible developer image, and a developing performance improving unit for controlling at least one of the photoconductive medium and the developing device to periodically form a patch developer image using developer that has uneven attributes (such as uneven coulomb per mass (Q/M)), and clean and remove the patch developer image. Accordingly, developer having uneven Q/M is periodically used for printing patch developer image and removed, thereby preventing the developer from being used for desired images, and thereby preventing inferior developing of desired images at the uneven-developer generating parts.

Abstract: A method and apparatus for applying a developing bias voltage of an image forming apparatus are provided. When an image is formed on paper, an AC bias voltage and a DC bias voltage are applied in an overlapping manner to the developing roller, and when an image is not formed on paper, the AC bias voltage is turned off and only the DC bias voltage is applied to the developing roller.

Abstract: A developing device for a liquid electrophotographic image forming apparatus is provided. The developing device may have a developing roller, which supplies ink to a photosensitive body on which an electrostatic latent image is formed and develops the electrostatic latent image. The apparatus may include an ink reservoir in which ink supplied to the developing roller is accommodated, and an ink removal unit, which removes ink remaining in the ink reservoir after a development operation is performed. The ink removal unit may comprise an ink removal member rotatably installed in the ink reservoir that exhausts ink through a through hole formed under the ink reservoir. A driving member rotates the ink removal member. An ink cartridge stores ink exhausted through the through hole.

Abstract: A wet electrophotographic image forming machine that informs a user of a timing for replacing development cartridges. The image forming machine comprises a control section for sensing the condition of the developer stored in one or more developer housings on the basis of a measured electric current flowing between one or more developer feeding members and one or more developer application members via the developer provided therebetween, and a display section for externally displaying the developer condition according to a signal from the control section. The control section evaluates the magnitude of the electric current and provides a signal to the control section for display if there is a developer amount or concentration deficiency.

Abstract: A wet electrophotographic image forming apparatus detects color per print page and executes printing by turning on only the development bias of a developing unit to be used for printing.

Abstract: A wet-type image forming apparatus and method is provided to sense and maintain a toner concentration level of a developer, and includes a counter for counting the number of dots of input print data, a memory for storing an average coverage of a print medium which corresponds to a predetermined dot number of the print data and storing a lookup table for consumption quantities of carrier and toner which correspond to the average coverage, and a control unit for calculating a toner concentration of a developer that remains in a developer supplying unit by recognizing consumption quantities of the carrier and the toner that are stored in the memory based on the counted dot number.

Abstract: A belt transfer device prevents the dragging of an image during a transfer process that transfers an image from a photosensitive body onto a transfer belt. The belt transfer device includes a transfer belt that contacts the surface of a photosensitive body, and at least one belt pressing member installed in the front and/or rear of a contact portion (that is, a transfer nip) between the transfer belt and the photosensitive body. The at least one belt pressing member extends the length of the transfer nip, thereby preventing image dragging.