Abstract: Disclosed is a method for controlling the temperature of a heat roller and an image forming apparatus based on the same. The image forming apparatus of the present invention includes: a heat roller for heating a printing paper having a toner image formed thereon to completely fuse the toner image to the printing paper; a heat lamp for heating the heat roller; and a controller for controlling the driving of the heat lamp, whereby the heat roller is maintained at a designated target temperature level during a pre-printing period. As such, it becomes possible to prevent a problem with the fusing process caused by low temperature of the heat roller during the pre-printing period for subsequent printing.

Abstract: A system and method of controlling printing are disclosed. The system and method comprise inputting image data printed by a printing section and a preset value for a print medium's size corresponding to the image data; measuring a size of each print medium being fed to the printing section; comparing the measured value for the each measured print medium and the preset value for the print medium's size; counting the number of times in which difference is occurred between the measured value and the preset value; and determining whether the print mediums fed to the printing section are different from the preset print medium's size by comparing the counted number of times and a predetermined reference number of times.

Abstract: A duplex electro-photographic developing machine including a printing medium tray loading a printing medium, a tray open/closed detecting unit detecting whether the printing medium tray has been opened and closed, a transferring roller transferring a toner image onto the printing medium, a resistance measuring unit measuring a resistance value of the printing medium passing the transferring roller, and a concentration controlling unit controlling a concentration of the toner image according to the measured resistance value measured by the resistance measuring unit in response to the printing medium tray having changed from an open state to a close state.

Abstract: A method and apparatus to control an image input and a recording-medium supply of an image forming apparatus. An aspect of the method comprises periodically generating synchronized demand of an image input into the exposure unit and supplying of a recording medium to the transfer unit, and inputting an image into the exposure unit according to the synchronized demand on image input and supplying a recording medium to the transfer unit according to the synchronized demand on recording-medium supply.

Abstract: A method and apparatus to prevent a transfer roller from being contaminated by toner in an image forming system, the method comprising setting a print region for a scanning operation according to a comparison result between a previous paper size in a paper cassette and a paper size in a driver; determining a current paper size in the paper cassette based on a time when front and rear ends of the paper are detected by a paper feeding sensor; comparing the current paper size in the paper cassette with the paper size in the driver; and if the paper size in the driver size is larger than the paper size in the paper cassette and the print region for the previous paper size in the paper cassette has not been set, determining a separation time of a transfer roller from a transfer belt in consideration of a delay time when the transfer roller is mechanically separated from the transfer belt after a separation command is applied to the transfer roller.

Abstract: An image forming apparatus and control method which use an intermediate transfer medium to transfer an image developed on an organic photoconductive medium onto a paper, and clean a surface of the intermediate transfer medium using a cleaning blade are provided. The apparatus and control method comprise driving the organic photoconductive medium and the intermediate transfer medium together with each other during a warming-up mode; stopping the organic photoconductive medium and the intermediate transfer medium until a print command is input during a stand-by mode; printing the developed image onto the paper sheet using the intermediate transfer medium in response to the print command; and reducing a friction between the intermediate transfer medium and the cleaning blade.

Abstract: A controlling method of an image forming apparatus for finely controlling the sensitivity of a density sensor in response to various changes of a printing environment. The controlling method of the image forming apparatus uses one or more of the following methods, alone or in any combination, to control the sensitivity of a density sensor. The methods can include a sensitivity correction method for controlling an output signal of the density sensor according to amount of light irradiated to an image carrier from a light source, a sensitivity correction method for correcting a reference value according to an output signal of the density sensor, and a sensitivity correction method for changing the signal output from the density sensor using a predetermined process.

Abstract: An apparatus and method of driving a transfer belt are disclosed. The apparatus and method comprise driving the transfer belt provided in an image forming apparatus by a predetermined distance when the transfer belt has been stopped for a predetermined time, and thus varying the contact portion with a plurality of rollers provided on the transfer belt. Image contamination due to deformation on the belt can be avoided. Additionally, because the rotation time of the driving source can be set to a predetermined time during the power-saving mode, power consumption can be minimized.

Abstract: Provided is a method and apparatus for controlling paper pickup in an image forming system. The method comprises (a) setting a number of re-attempts of pickup of paper and a number of no-load operations of a transfer belt, respectively, and (b) performing a paper pickup operation repeatedly in accordance with the set number of re-attempts of pickup of paper and the set number of no-load operations of the transfer belt when paper pickup is not successfully performed.

Abstract: Provided is a method and apparatus for preventing contamination of a transfer roller in an image forming system. The method comprises (a) setting a separation time of the transfer roller from a transfer belt according to the size of paper picked-up from a paper feeding cassette and the size of paper set in a printer driver, and (b) separating the transfer roller from the transfer belt when the separation time of the transfer roller set in (a) has elapsed.

Abstract: Provided is a method and apparatus for preventing a transfer roller from being contaminated by toner in an image forming system, the method comprising determining a size of paper based on a time when front and rear ends of the paper are detected by a paper feeding sensor; comparing a size of an image formed on a photosensitive drum with the size of the paper; and if the size of the paper is the same as or smaller than the size of the image, determining a separation time of a transfer roller from a transfer belt in consideration of a delay time when the transfer roller is mechanically separated from the transfer belt after a separation command is applied to the transfer roller.

Abstract: An image forming apparatus is configured to facilitate design modification. The image forming apparatus has an engine mechanism to carry out a printing job with respect to a print data applied from an external device, an image processing unit to convert the print data into image data, and an engine controlling unit to control the engine mechanism to carry out the print job with respect to the image data. The engine controlling unit and the image processing unit are arranged on a single printed circuit board (PCB) in which a first and a second division are defined, with the engine controlling unit being arranged in the first division and the image processing unit being arranged in the second division. A circuit element in the second division is shared by the engine controlling unit and the image processing unit to reduce costs and redesign time.

Abstract: A method and apparatus to control an image input and a recording-medium supply of an image forming apparatus. An aspect of the method comprises periodically generating synchronized demand of an image input into the exposure unit and supplying of a recording medium to the transfer unit, and inputting an image into the exposure unit according to the synchronized demand on image input and supplying a recording medium to the transfer unit according to the synchronized demand on recording-medium supply.

Abstract: An image forming apparatus is configured to facilitate design modification. The image forming apparatus has an engine mechanism to carry out a printing job with respect to a print data applied from an external device, an image processing unit to convert the print data into image data, and an engine controlling unit to control the engine mechanism to carry out the print job with respect to the image data. The engine controlling unit and the image processing unit are arranged on a single printed circuit board (PCB) in which a first and a second division are defined, with the engine controlling unit being arranged in the first division and the image processing unit being arranged in the second division. A circuit element in the second division is shared by the engine controlling unit and the image processing unit to reduce costs and redesign time.

Abstract: A duplex electro-photographic developing machine including a printing medium tray loading a printing medium, a tray open/closed detecting unit detecting whether the printing medium tray has been opened and closed, a transferring roller transferring a toner image onto the printing medium, a resistance measuring unit measuring a resistance value of the printing medium passing the transferring roller, and a concentration controlling unit controlling a concentration of the toner image according to the measured resistance value measured by the resistance measuring unit in response to the printing medium tray having changed from an open state to a close state.

Abstract: A printer and a method of driving a cooling fan of the printer include a storage unit temporarily stores printing option data and image data, and a control unit controls an operation of a printing unit in one of a warming-up mode, a standby mode, a printing mode and a sleep mode based on the printing option data and the image data as inputted into the control unit. The control unit outputs a control signal variably controlling an RPM (Rotation Per Minute) of the cooling fan based on the operation mode and a printing speed of the printing unit. A cooling fan driving unit drives the cooling fan at a different RPM based on the control signal input from the control unit. Accordingly, the printer and the method of driving the cooling fan of the printer are capable of shortening the warming-up time to increase an initial printing speed, preventing the printing unit from being overheated, extending a lifespan of the cooling fan, and reducing a power consumption.

Abstract: Disclosed is a method for controlling the operation of a fan in an electronic photo device including a developing device, a fan for keeping the temperature in the electronic photo device uniformly, and an output sensor for sensing output of a printed paper. According to the method, when a printable medium to be printed with print data is located between a transferring roller and an OPC drum of the developing device, the sort of the printable medium is determined. If it is determined that the printable medium is a first printable medium, the fan is stopped and a fixing process is performed. Otherwise, if it is determined that the printable medium is a second printable medium, the fixing step is performed under the condition that the fan is not stopped.