KR100265132B1 - Transfer voltage control method for laser beam printer - Google Patents

Abstract

PURPOSE: A method for controlling transfer voltage according to specific resistance of a writing paper in high speed printing by using a laser beam is provided to prevent lowering of quality of image even in high speed printing. CONSTITUTION: In the method for controlling transfer voltage according to specific resistance of the writing paper in high speed printing by using the laser beam, a few stages are included. In the stage of 400, the order of printing is received. If the high speed printing is carried out in the stage of 402, the writing paper is supplied in the stage of 406. If the high speed printing isn't carried out in the stage of 402, the appropriate operation is carried out in the stage of 404. In the stages of 408, 412, the first end zone of the writing paper is permitted. In the stage of 410, the transfer voltage is set up. In the stage of 414, printing is carried out with the estimated transfer voltage. In the stage of 416, the specific resistance of the writing paper is measured. In the stage of 418, the transfer voltage is reset up. In the stage of 420, printing is carried out with the reset transfer voltage. In the stage of 422, high speed printing is carried out.

Description

Transfer voltage control method according to resistivity of recording paper during high speed printing using laser beam printer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam printer, and more particularly, to a method of controlling a transfer voltage according to a resistivity of a recording paper during high speed printing using a laser beam printer.

In general, a laser beam printer refers to an apparatus for printing a predetermined image on a recording paper through a series of electrophotographic processes consisting of charging ⇒ exposure ⇒ development ⇒ transfer ⇒ settlement ⇒ media, and is a schematic engine of the laser beam printer. The configuration of the mechanism is shown in FIG. The operation of the laser beam printer will be described briefly with reference to FIG. 1.

When printing starts, first, recording paper is sequentially fed sheet by sheet by the pickup roller 20 from the paper feeding cassette 10 in which a plurality of recording papers P are loaded. Then, the recording paper fed by the pickup roller 20 arrives at the feed roller 30, and the tip of the recording paper is aligned, and then the toner is heated on the recording paper while passing through the developing unit 40 and the fixing unit 50. After the fixation is carried out to form an image, the discharge roller is discharged by the discharge roller 60.

In the case of the conventional laser beam printer as described above, the transfer voltage is fixed based on the resistivity value of the general recording paper in advance. When printing at a constant transfer voltage as described above, the thickness of the recording paper, the humidity content, and the recording When the resistivity value of the recording paper fed by the change of the quality of the paper is changed, there is a problem that the quality of the image is deteriorated due to the change of the current values flowing through the conductive transfer roller, the recording paper and the photosensitive drum surface. In order to solve this problem, conventionally, at the time when the recording paper enters between the transfer roller and the photosensitive drum, the current value flowing through the transfer roller and the recording paper photosensitive drum surface is measured, and the measured value is measured by the change of the resistivity of the recording paper. When the current value changes, the transfer voltage is appropriately varied to keep the current value constant at the reference current value, thereby preventing deterioration of the image.

However, when performing high speed printing using the laser beam printer, it is difficult to measure the accurate current value flowing through the transfer roller, the recording paper, and the photosensitive drum surface, and the error is increased even when the current value is measured. Can not effectively prevent deterioration of the image. In addition, in the case of high speed printing, the recording paper has a high feed speed, so when the recording paper enters between the transfer roller and the photosensitive drum, the current flowing through the surface of the transfer roller, the recording paper and the photosensitive drum is measured to maintain the reference current There has been a problem that an image cannot be printed on the leading edge of the recording paper because the leading edge of the recording paper is already transferred during the time for setting the proper transfer voltage.

As described above, when performing high speed printing using a laser beam printer, it is difficult to measure the accurate current value flowing through the transfer roller, the recording paper, and the photosensitive drum surface, and the error of the measured current value is also increased. The conventional method could not effectively prevent deterioration of the image. In addition, due to the high transfer speed of the recording paper, a large amount of the leading edge of the recording paper is transferred during the proper transfer voltage setting time according to the resistivity value of the recording paper, thereby preventing the image from being properly printed on the leading edge of the recording paper.

It is therefore an object of the present invention to provide a transfer voltage control method according to the resistivity of a recording paper which prevents the image quality from deteriorating even at high speed printing.

1 is a schematic engine mechanism diagram of a conventional laser beam printer;

2 is a block diagram of a conventional laser beam printer,

3 is a view showing a transfer roller and a photosensitive drum portion of the engine mechanism of the laser beam printer to which the present invention is applied;

Figure 4 is a flow chart of the transfer voltage control according to the resistivity value of the recording paper during high-speed printing in a laser beam printer according to an embodiment of the present invention.

In order to achieve the above object, the present invention measures the resistance value between the transfer roller and the photosensitive drum before the recording paper reaches the transfer roller in high speed printing using a laser beam printer to estimate the resistance value when the recording paper is present. After applying the transfer voltage and measuring the resistivity of the recording paper by measuring the current flowing through the surface of the transfer roller, the recording paper and the photosensitive drum, when the tip of the recording paper enters between the transfer roller and the photosensitive drum, The transfer voltage may be changed to an appropriate transfer voltage according to the specific resistance so as to maintain the changed transfer voltage during one printing operation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Many specific details are set forth in the following description and in the accompanying drawings to provide a more general understanding of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 is a block diagram of a conventional laser beam printer. Referring to FIG. 2, the laser beam printer includes a video controller 40, a print engine unit 50, and an OPE 48. Referring to FIG. The video controller 40 includes a computer interface 42 for interfacing an input / output signal with a host computer, a video controller 44, and an engine interface 46. The video controller 44 converts the code data received through the computer interface 42 into image data that can be processed by the printer engine in accordance with a predetermined program, and transmits the image data to the print engine unit 50, and the host computer and the OPE 48. RAM for temporarily storing the various data inputted from), and a ROM having a control program according to the present invention. In addition, the ROM includes a table in which a transfer voltage corresponding to a resistance value between the transfer roller and the photosensitive drum is recorded, and a table in which the resistivity value of the recording paper and the transfer voltage corresponding thereto are recorded. The engine interface 46, which is connected between the video controller 44 and the print engine 50, interfaces the input / output signal with the print engine 50 under the control of the video controller 44. On the other hand, the OPE 48 having a plurality of keys and a display device is connected to the video control unit 44 to apply key data generated from the plurality of keys to the video control unit 44 and to display information according to a printing operation. . The print engine unit 50 includes a video interface 52, an engine control unit 54, an I / O interface 56, a sensor circuit 58, a mechanical drive unit 60, and an electrophotographic developing unit 62. Is connected to the controller 40. The video interface 52 provides an interface for transmission / reception signals between the video controller 40 and the engine controller 54. The engine control unit 54 controls the mechanical drive unit 60 and the electrophotographic developing unit 62 under the control of the video control unit 44 to print an image according to the image data received from the video control unit 44 on the recording paper. The sensor circuit 58 monitors the operation status of each part of the print engine unit 50, the presence or absence of recording paper, and the recording paper conveying state. The I / O interface 56 is connected between the engine control unit 54, the sensor circuit 58, the mechanical drive unit 60, and the electrophotographic developing unit 62 to interface the input / output signals of the engine control unit 54. . The sensor circuit 58 drives various sensors for monitoring the operation state of each part of the print engine unit 50, the presence or absence of recording paper, and the recording paper transfer state, and transmits the detection signal of each sensor to the engine controller 54. to provide. The mechanism driving unit 60 drives various mechanisms for feeding, feeding and printing the recording paper under the control of the engine control unit 54. The electrophotographic developing unit 62 is controlled by the engine control unit 54 and prints an image according to the image data on a recording sheet by an electrophotographic developing method.

FIG. 3 shows only a transfer roller and a photosensitive drum portion to which the present invention is applied among the engine mechanisms of the laser beam printer shown in FIG. 1. Referring to FIG. 3, section 1 shows a paper cassette for recording paper P. FIG. (10) indicates the time before the paper is fed between the photosensitive drum 300 and the transfer roller 302, the interval 2 is the recording paper (P) enters between the photosensitive drum 300 and the transfer roller 302 From the front end of the recording paper P to a predetermined length, for example, 8 mm in length, between the photosensitive drum 300 and the transfer roller 302.

4 is a flowchart illustrating a process performed by an engine controller for automatically adjusting a transfer voltage according to a specific resistance value of a recording paper fed during high speed printing in a laser beam printer according to an exemplary embodiment of the present invention. The operation according to the flowchart of FIG. 4 is performed by the engine controller 54 of FIG. 2. Now, embodiments of the present invention will be described in detail with reference to FIGS. 2, 3, and 4.

First, the engine control unit 54 of the laser beam printer checks whether or not a print command is received from the video control unit 44 through the video interface 52 in step 400 to receive a print command from the video control unit 44. When the engine control unit 54 proceeds to step 402 to check whether the print command is a high speed printing command. At this time, if the print command is not a high speed printing command, the engine controller 54 proceeds to step 404 to perform a normal corresponding operation according to a preset process.

On the contrary, if the print command is the high speed printing command in step 402, the engine control unit 54 proceeds to step 406 to control the paper feed roller 10 to feed the recording paper P from the paper cassette 10. . Accordingly, the sheet of paper P is fed one by one from the paper cassette 10 so that the leading edge of the sheet of paper P enters section 1 shown in FIG. In response to this, the engine controller 54 recognizes that the recording paper P has entered section 1 in step 408, and proceeds to step 410 to determine the gap between the transfer roller 302 and the photosensitive drum 300. The resistance value is measured to estimate the resistance value when the recording paper P is present, and then the transfer voltage for optimizing the image quality is set with reference to the estimated resistance value and applied to the transfer roller 302. The resistance value between the transfer roller 302 and the photosensitive drum 300 may be measured by measuring a current value flowing through the surface of the transfer roller 302 and the photosensitive drum 300 and the transfer voltage for optimizing the quality of the image. The setting of is determined by referring to a transfer voltage table corresponding to the measured resistance value provided in advance in the ROM. Then, the engine controller 54 proceeds to step 412 to indicate that the leading edge of the fed recording paper P enters the interval 2 shown in FIG. 3, that is, between the transfer roller 302 and the photosensitive drum 300. If it is detected that the front end of the recording paper P enters section 2, the process proceeds to step 414 to control the mechanism driving unit 60 and the electrophotographic developing unit 62 in step 410. While performing the printing operation with the set transfer voltage, the process proceeds to step 416 to measure and record the current values flowing through the surface of the transfer roller 302, the recording paper P, and the photosensitive drum 300 during the printing operation. Measure the resistivity of the paper P. Next, the engine controller 54 proceeds to step 418 to reset the transfer voltage for optimizing the image quality by referring to the resistivity value of the recording paper P measured in step 416, and the transfer roller 302. To apply. At this time, the resetting of the transfer voltage is also determined by referring to the transfer voltage table corresponding to the specific resistance value of the recording paper P provided in advance in the ROM. Then, the engine controller 54 proceeds to step 420 to apply the transfer voltage reset in step 418 to the transfer roller 302 to perform a printing operation. Next, the engine controller 54 proceeds to step 422 to check whether the printing operation is completed. If the printing operation is not completed, the engine controller 54 returns to step 420 to supply paper thereafter until the printing operation is completed. For the recording paper P, the printing operation is performed with the transfer voltage reset in step 418.

Therefore, in high speed printing, the transfer voltage is set to optimize the image quality by measuring the resistivity value of the first recording paper without resetting the transfer voltage for each recording paper, and then feeding the paper until one printing operation is completed. For the recording paper, the printing operation is performed by applying the first set transfer voltage as it is, thereby reducing the repetition of the transfer voltage resetting process and performing a high speed printing operation with an appropriate transfer voltage.

As described above, in the present invention, when performing high speed printing with a laser beam printer, the transfer voltage is measured by measuring the resistivity value of the recording paper only for the recording paper that is fed first during one printing operation without resetting the transfer voltage for each recording paper. By optimizing it, there is an advantage that a high speed printing operation can be performed at an appropriate transfer voltage while reducing the repetition of the transfer voltage reset process.

Claims (1)

In the method for controlling the transfer voltage according to the resistivity of the recording paper during high speed printing using a laser beam printer, When the high speed printing command is received from the host, the recording paper is measured by measuring a resistance value between the transfer roller and the photosensitive drum in the idle section before the leading edge of the recording paper fed one by one from the paper cassette enters between the transfer roller and the photosensitive drum. Estimating a specific resistance value of and setting a transfer voltage according to the estimated specific resistance value; When the leading edge of the recording paper enters between the transfer roller and the photosensitive drum, the set transfer voltage is applied to the transfer roller to perform a printing operation and at the same time measuring the resistivity of the recording paper, Resetting an appropriate transfer voltage and applying it to the transfer roller; The recording paper for high speed printing using the laser beam printer, characterized in that for the recording paper fed after the resetting of the transfer voltage, the printing operation is performed with the reset transfer voltage until the one printing operation is completed. Voltage control method according to the specific resistance of