Abstract: A method and apparatus for forming an image determine if printing paper is properly picked up, and printing data is transferred to an intermediate transfer belt (ITB). When it is sensed that the printing paper is not properly picked up, picking up the printing paper is retried considering a revolution cycle of the ITB. Thus, the frequency of errors can be decreased, and a user's convenience can be increased because picking up the printing paper is automatically retried whenever mis-pick up occurs instead of displaying an error. Further, wasting of toner is decreased.

Abstract: A method and apparatus for forming an image determine if printing paper is properly picked up, and printing data is transferred to an intermediate transfer belt (ITB). When it is sensed that the printing paper is not properly picked up, picking up the printing paper is retried considering a revolution cycle of the ITB. Thus, the frequency of errors can be decreased, and a user's convenience can be increased because picking up the printing paper is automatically retried whenever mis-pick up occurs instead of displaying an error. Further, wasting of toner is decreased.

Abstract: An apparatus and a method recognizing the error of a toner sensor that is capable of correctly recognizing the error factor of the toner sensor for sensing the amount of the toner of a developing device main body. The output value and the set value of the sensor are compared with each other to display the corresponding error code. Therefore, a service engineer or a user easily recognizes the error factor to take proper measures corresponding to the error factor.

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 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: An image forming apparatus and a method of detecting a home position error are provided. The image forming apparatus includes a plurality of developing units, a cam shaft, and a plurality of cams that are formed on the cam shaft to correspond to the respective developing units. A power transmitting element is installed between the plurality of developing units and the plurality of cams and selectively transmits a rotational force of a driving source to the plurality of developing units according to a rotational phase of the cam shaft. An indicating element is installed on the cam shaft and includes a plurality of indicating units. A sensor senses the plurality of indicating units. A home position error is detected each time when the indicating units pass through the sensor.

Abstract: A method and apparatus for forming an image determine if printing paper is properly picked up, and printing data is transferred to an intermediate transfer belt (ITB). When it is sensed that the printing paper is not properly picked up, picking up the printing paper is retried considering a revolution cycle of the ITB. Thus, the frequency of errors can be decreased, and a user's convenience can be increased because picking up the printing paper is automatically retried whenever mis-pick up occurs instead of displaying an error. Further, wasting of toner is decreased.

Abstract: Disclosed are a method of preventing overheating of a fuser assembly and an apparatus using the same. The method of preventing overheating of a fuser assembly includes inspecting whether a temperature of a fuser assembly is higher than a predetermined temperature. If the temperature of the fuser assembly is higher than the predetermined temperature it is determined whether there is a print command. A print sheet is passed through the fuser assembly, and conveyed to a predetermined location when there is no print command. The temperature is again inspected if there is no print command. If the temperature is lower than the predetermined temperature it is determined whether a predetermined time has lapsed. The temperature is again inspected if the predetermined time did not lapse.

Abstract: An image forming apparatus and a method of detecting a home position error are provided. The image forming apparatus includes a plurality of developing units, a cam shaft, and a plurality of cams that are formed on the cam shaft to correspond to the respective developing units. A power transmitting element is installed between the plurality of developing units and the plurality of cams and selectively transmits a rotational force of a driving source to the plurality of developing units according to a rotational phase of the cam shaft. An indicating element is installed on the cam shaft and includes a plurality of indicating units. A sensor senses the plurality of indicating units. A home position error is detected each time when the indicating units pass through the sensor.

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: 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: Provided is a method of controlling a fusing speed of an image forming apparatus. Determination is made as to whether a sheet of paper to be printed is a special-purpose sheet. Determination is made as to whether a length 1 of the sheet of paper is shorter than a distance L1 between a second transfer roller and a fusing unit. Determination is also made as to whether the length 1 of the sheet of paper is shorter than a distance L0 between a first transfer roller and the second transfer roller. Determination is made as to whether the length 1 of the sheet of paper is longer than the distance L0 between the first transfer roller and the second transfer roller.

Abstract: An apparatus and a method recognizing the error of a toner sensor that is capable of correctly recognizing the error factor of the toner sensor for sensing the amount of the toner of a developing device main body. The output value and the set value of the sensor are compared with each other to display the corresponding error code. Therefore, a service engineer or a user easily recognizes the error factor to take proper measures corresponding to the error factor.

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 image forming apparatus and a method of detecting a home position error are provided. The image forming apparatus includes a plurality of developing units, a cam shaft, and a plurality of cams that are formed on the cam shaft to correspond to the respective developing units. A power transmitting element is installed between the plurality of developing units and the plurality of cams and selectively transmits a rotational force of a driving source to the plurality of developing units according to a rotational phase of the cam shaft. An indicating element is installed on the cam shaft and includes a plurality of indicating units. A sensor senses the plurality of indicating units. A home position error is detected each time when the indicating units pass through the sensor.

Abstract: Provided is a method of controlling a fusing speed of an image forming apparatus. Determination is made as to whether a sheet of paper to be printed is a special-purpose sheet. Determination is made as to whether a length l of the sheet of paper is shorter than a distance L1 between a second transfer roller and a fusing unit. Determination is also made as to whether the length l of the sheet of paper is shorter than a distance L0 between a first transfer roller and the second transfer roller. Determination is made as to whether the length l of the sheet of paper is longer than the distance LO between the first transfer roller and the second transfer roller.

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: 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 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: Disclosed are a method of preventing overheating of a fuser assembly and an apparatus using the same. The method of preventing overheating of a fuser assembly includes inspecting whether a temperature of a fuser assembly is higher than a predetermined temperature. If the temperature of the fuser assembly is higher than the predetermined temperature it is determined whether there is a print command. A print sheet is passed through the fuser assembly, and conveyed to a predetermined location. The temperature is again inspected if there is no print command. If the temperature is lower than the predetermined temperature it is determined whether a predetermined time has lapsed. The temperature is again inspected if the predetermined time did not lapse.