KR19990038550A - Transfer voltage control circuit and method - Google Patents

Abstract

When a transfer voltage for driving the transfer roller is supplied, the transfer roller is amplified and corrected so as to easily detect a voltage fed back when the voltage is inversely fed back, the noise is removed through filtering, and the transfer roller is detected according to the detected feedback voltage. Recognizes the environment of the control the transfer voltage supplied to the transfer roller.

Therefore, in addition to the transfer voltage supplied to the transfer roller to control the transfer voltage supplied to the transfer roller, the voltage fed back is detected through the amplification step, the comparison step, and the filtering step. It is easy to detect, and there is an advantage of detecting a voltage from which an error such as noise generated during the feedback process is removed by adding a filtering step.

Description

Transfer voltage control circuit and method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer voltage control circuit and method, and more particularly, to amplify, correct, and correct a voltage fed back in inverse proportion to a transfer voltage supplied to a transfer roller to control a transfer voltage supplied to a transfer roller in a laser beam printer. The present invention relates to a transfer voltage control circuit and method for recognizing an environment of a transfer roller and then adjusting a transfer voltage supplied to the transfer roller by being detected by filtering.

In general, a printer is an office automation device connected to a computer and receives a print data created or edited by an application program of the computer, and converts the print data into a print language suitable for the set printing conditions. It is a device to print on paper using colored dye.

A general laser beam printer will be described with reference to FIG. 1 as follows.

A laser beam printer using toner as a printing dye performs a print job by using an electrophotographic process method.

Laser Scanning Unit (LSU) 1 for scanning a light source to form an image, a developer 2 for spraying toner when the light is formed, a photosensitive drum 3 for generating an electro-static image, and a photosensitive A transfer roller 4 for transferring the toner formed on the drum 3 to the paper, a heating roller 5 for fixing the toner transferred to the paper by heat, and a heating roller 5 so that the toner is fixed to the paper. And a discharge roller 7 and 7 'for outputting the fixed sheet.

In the process of performing a printing operation, a charging roller (not shown) rotates to evenly charge an image on the surface of the photosensitive drum 3, and converts a digital signal into light on the surface of the charged photosensitive drum 3. The LSU 1 generates an electrostatic latent image identical to the image output from the computer. In this way, the electrostatic latent image generated on the photosensitive drum 3 is developed by the toner as it passes through the developing unit 2 to become a visible image. When the paper loaded in the paper cassette is fed into the printer by the pickup roller, the paper is transferred to the transfer roller. While passing through (4), opposite charges are charged on the back side so that the visible image of the photosensitive drum 3 is transferred onto the paper, and the paper on which the visible image is transferred passes between the heating roller 5 and the pressing roller 6, After the image transferred by pressing is settled, the paper is discharged through the discharge rollers 7 and 7 'according to the set transfer path, thereby completing the execution of the print job.

Here, a voltage for driving the transfer roller is supplied to transfer the toner to the paper. The transfer voltage must be supplied within an appropriate range so that the toner is transferred to an optimum state so that a transfer failure does not occur. For example, if the transfer voltage is low, the electrostatic attraction generated by the transfer roller is weak, and the toner is not adhered to the paper efficiently so that transfer tremor occurs. When the transfer voltage is high, the toner of the photosensitive drum is reversed and the toner is applied to the paper. The electrostatic attraction that is not in close contact or generated by the transfer roller is strong so that the toner is transferred onto the print paper and the images are scattered before the print paper approaches the photosensitive drum. Therefore, the transfer failure can be prevented only by supplying the transfer voltage in the appropriate range to the transfer roller, thereby improving the transfer efficiency.

In such a printer, the transfer voltage required by the transfer roller is affected by the transfer environmental resistance between the transfer roller and the photosensitive drum, the properties of the toner and the printing paper, and the appropriate range of transfer voltage is affected by the transfer environmental resistance. The transfer environmental resistance is affected by changes in the environment such as temperature and humidity. Transfer voltage applied to the transfer roller by detecting the voltage fed back according to the transfer voltage passing through the transfer roller to control and supply the transfer voltage changed according to the environment in an appropriate range, and comparing the voltage detected by the power supply with a set reference value. To adjust the voltage. At this time, the voltage detected by the feedback decreases according to the change of the transfer roller environment, and thus the detection is not easy, and the error caused by the error or noise generated during the feedback cannot be solved, and thus the voltage fed back is not accurately detected.

However, according to the conventional method for controlling the transfer voltage as mentioned above, the following problems occur.

(1) When the environmental resistance of a transfer roller becomes large and the voltage fed back becomes small, it is not easy to detect this.

(2) When a distorted value is detected according to an error or noise generated during feedback during the detection of the feedback voltage, the state of the transfer roller cannot be accurately determined, and the range of the transfer voltage supplied to the transfer roller can be controlled within an appropriate range. none.

Accordingly, the present invention is to solve the above problems, an object of the present invention is to correct the voltage fed back inversely proportional to the transfer voltage supplied to the transfer roller to easily detect the environment of the transfer roller and accordingly transfer roller To provide a transfer voltage control circuit and method for controlling the transfer voltage applied to within an appropriate range.

1 is an exemplary view schematically showing an internal structure of a general laser printer;

2 is a block diagram showing a circuit for controlling a transfer voltage by correcting a voltage fed back according to the present invention;

3 is a circuit diagram illustrating an embodiment for correcting a voltage fed back according to the present invention;

4 is a waveform diagram showing a transfer voltage according to the present invention and the voltage fed back at each stage according to the present invention;

5 is a flowchart illustrating a method for controlling a transfer voltage according to the present invention.

<Description of the code | symbol about the principal part of drawing>

8: Transfer voltage output section 9: Transfer roller

10: sensing section 11: amplifying circuit section

12: correction circuit section 13: comparison section

14: noise reduction circuit

A feature of the present invention for achieving the above objects is that, in a printer including a transfer roller, a transfer voltage supplied from a power supply unit under control of a controller to perform a transfer step of transferring toner to a paper during a print job. A circuit for controlling, the circuit comprising: a transfer voltage output unit for receiving power from the power supply unit to rectify and supply a transfer voltage to the transfer roller; A detector configured to detect a feedback voltage output from the transfer voltage output unit in inverse proportion to a transfer voltage supplied to the transfer roller; An amplifier circuit unit for amplifying the feedback voltage sensed by the detector; A correction circuit section for driving in accordance with the divided voltage distributed from the transfer voltage supplied to the transfer roller and for supplying a constant level of a constant voltage; A comparison unit for receiving and comparing a voltage output from the amplifying circuit unit and a constant voltage supplied from the correction circuit unit; And a noise removing circuit unit which removes noise of the voltage output from the comparing unit and feeds it back to the analog / digital converting unit of the control unit.

Preferably, the comparison unit subtracts the amplified voltage from the constant voltage.

Further, another feature of the present invention is a method for controlling a transfer voltage supplied from a power supply unit under control of a control unit to perform a transfer step of transferring a toner to paper during a print job in a printer including a transfer roller. A transfer voltage supply step of supplying a transfer voltage to the transfer roller; A feedback voltage sensing step of sensing a voltage fed back in inverse proportion to the supplied transfer voltage; An amplifying step of amplifying the sensed feedback voltage; A constant voltage supplying step of supplying a constant voltage maintaining a constant level; A comparison step of comparing the supplied constant voltage and the amplified voltage; And filtering to remove noise from the subtracted voltage to feed back the filtered voltage to an analog / digital converter of the controller.

Preferably, the comparing step is to subtract the amplified voltage from the constant voltage.

Hereinafter, a circuit and a method for controlling a transfer voltage according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic block diagram for controlling the transfer voltage by correcting the voltage fed back to control the transfer voltage according to the present invention.

In order to control the transfer voltage supplied to the transfer roller which is driven to transfer the toner on the paper during the printing operation, the transfer voltage output unit 8, which supplies the transfer voltage so that the transfer step is performed, the transfer voltage output unit ( 8) When the transfer voltage is supplied from the transfer roller 9 for transferring the toner to the paper, the sensing unit 10 for detecting the fed back voltage in inverse proportion to the transfer voltage supplied to the transfer roller 9, the detected voltage The amplification circuit section 11 to amplify, the correction circuit section 12 which is driven according to the voltage distributed from the transfer voltage supplied to the transfer roller, and supplies a constant voltage which maintains a constant level of potential, and the constant voltage supplied from the correction circuit section 12. And a comparison section 13 for comparing the voltage output from the amplifying circuit section 11 and a noise removal circuit section 14 for removing noise generated in the voltage output from the comparison section 13. It is.

When power is supplied from the power supply unit, a transfer voltage of a predetermined level for driving the transfer roller 9 is output from the transfer voltage output unit 8 so that the toner is transferred to the paper, and the output transfer voltage is supplied to the correction circuit unit 12. It is also entered as). Meanwhile, a feedback voltage inversely proportional to the transfer voltage supplied from the transfer voltage output unit 8 to the transfer roller 9 is output and sensed by the detector 10. The sensed voltage is amplified by the amplifier circuit 11 and input to the comparator 13, and the constant voltage supplied from the correction circuit 12 is also input to the comparator 13. The comparator 13 compares the input constant voltage with the amplified voltage and outputs the output voltage, and the output voltage is filtered while passing through the noise canceling circuit 14, and then the analog / digital converter (hereinafter referred to as 'ADC'). Abbreviated d).

Here, since the feedback voltage is fed back in inverse proportion to the transfer voltage supplied to the transfer roller 9, when the feedback voltage is detected, the environment of the transfer roller 9 can be recognized, and accordingly, the control of a control unit (not shown) The transfer voltage supplied to the furnace transfer roller 9 is adjusted.

3 is a circuit diagram illustrating an embodiment of correcting a voltage fed back to control a transfer voltage according to a block diagram according to the present invention.

The magnitude of the voltage fed back according to the transfer voltage supplied from the transfer voltage output unit 8 to the transfer roller 9 is determined. The transfer voltage supplied to the transfer roller 9 is dependent on the environmental resistance of the transfer roller 9. When determined, an inverse voltage is fed back. That is, according to the recognized fact that the current fed back by I = V / R is relatively reduced when the conductive resistance is large, the environmental resistance of the transfer roller 9 is large, and the feedback is increased when the voltage supplied to the transfer roller 9 becomes large. Since the amount of current to be distributed is small, the voltage proportional to this becomes small. If the environmental resistance of the transfer roller 9 is small, the amount of current to be distributed becomes large and the voltage fed back is also large. The feedback voltage is sensed at both ends of the resistance Rs of the sensing unit 10 so that the environmental resistance of the transfer roller 9 can be recognized. If the detected voltage is minute, it can be easily detected after being fed back. Therefore, the signal is amplified by 1 + Rf / R1 and transmitted to the comparator 13 while passing through the amplifier OP1 of the amplifier circuit 11 to amplify the feedback voltage.

Here, the correction circuit section 12 is configured to supply a constant level constant voltage to supply a constant voltage. The correction circuit section 12 is driven according to the voltage distributed in the transfer voltage supplied to the transfer roller 9, and the correction circuit section ( The constant constant voltage is supplied to the comparator 13 by the time constant of the resistors R2 to R5 constituted in 12).

The comparator 13 in which the constant voltage supplied through the transistor Tr1 is input from the correction circuit unit 12 and the voltage amplified in the amplifying circuit unit 11 is input, subtracts and outputs the voltage amplified from the constant voltage. The output voltage passes through the noise canceling circuit section 14 and is fed back to the ADC section. When the feedback voltage is detected, the environment of the transfer roller 9 is recognized under the control of the controller, and then the transfer voltage is adjusted to be supplied to the transfer roller 9 within an appropriate range.

4A to 4E are waveform diagrams showing the transfer voltage supplied to the transfer roller according to the present invention at each point Va to Ve shown in FIG. 3 and the voltage fed back accordingly. 4A is an output waveform of the transfer voltage Va supplied to the transfer roller 9 according to the environmental resistance of the transfer roller 9, and FIG. 4B is feedback detected by the sensing unit 10 according to the transfer voltage of FIG. 4A. The voltage Vb is shown. When the voltage supplied to the transfer roller 9 increases, the feedback voltage sensed by the sensing unit 10 decreases. 4C illustrates the voltage Vc at the output terminal of the amplifying circuit unit 11 after amplifying the feedback voltage Vb sensed by the sensing unit 10, and FIG. 4D illustrates the correction circuit unit 12. Indicates the potential level Vd of the constant voltage supplied from FIG. 4E shows the overlapped voltage Vd-Vc in the comparator 13 in which the amplified voltage Vc in FIG. 4C is subtracted from the constant voltage Vd supplied from the correction circuit unit 12 of FIG. 4D. Indicates the waveform.

5 is a flowchart illustrating a method for controlling a transfer voltage in accordance with the present invention.

When a predetermined level of transfer voltage is supplied from the transfer voltage output section 8 to the transfer roller 9 (S1), the transfer roller 9 is driven to transfer the toner to the paper, and a feedback voltage inversely proportional to the supplied transfer voltage. This sensing unit 10 is detected (S2). The sensed voltage is then amplified through the amplifier circuit 11 to be easily detected (S3) and input to the comparator 13. In addition, the comparator 13 is input from the correction circuit unit 12 to maintain a constant voltage potential (S4). In accordance with the inputs of steps S3 and S4, the comparator 13 subtracts the voltage amplified by the amplifying circuit section 11 from the constant voltage supplied from the correction circuit section 12 (S5), and the subtracted voltage is noise. The filter is filtered to remove noise generated through the elimination circuit unit 14 (S6), and then fed back to the ADC unit (S7).

Thereafter, by detecting the feedback voltage, the environment of the current transfer roller 9 can be recognized, and accordingly, the voltage supplied to the transfer roller 9 can be adjusted.

Therefore, the voltage during the feedback process so that the voltage fed back can be easily detected in inverse proportion to the voltage supplied to the transfer roller to control the transfer voltage supplied to the transfer roller for performing the step of transferring the toner to the paper during the print job. By amplifying, comparing, and filtering, the transfer voltage can be adjusted to an appropriate range and applied to the transfer roller in accordance with the detection of the feedback voltage.

As a result, the transfer voltage control circuit according to the present invention has the following advantages.

(1) The voltage fed back by the amplifying step and the comparing step because the voltage fed back is detected through the amplifying step, the comparing step, and the filtering step in addition to the transfer voltage supplied to the transfer roller to control the transfer voltage supplied to the transfer roller. Can be easily detected, and a filtering step can be added to detect a voltage from which an error such as noise generated during the feedback process is removed.

(2) When the voltage is easily detected, an optimum printed matter can be realized because the transfer voltage can be adjusted to an appropriate range and applied to the transfer roller under the control of the controller.

Claims (4)

In a printer including a transfer roller, in a circuit for controlling a transfer voltage supplied from a power supply unit under control of a control unit to perform a transfer step of transferring a toner to paper during a print job: A transfer voltage output unit configured to receive power from the power supply unit to rectify and supply a transfer voltage to the transfer roller; A detector configured to detect a feedback voltage output from the transfer voltage output unit in inverse proportion to a transfer voltage supplied to the transfer roller; An amplifier circuit unit for amplifying the feedback voltage sensed by the detector; A correction circuit section for driving in accordance with the divided voltage distributed from the transfer voltage supplied to the transfer roller and for supplying a constant level of a constant voltage; A comparison unit for receiving and comparing a voltage output from the amplifying circuit unit and a constant voltage supplied from the correction circuit unit; And, And a noise removing circuit unit which removes noise of the voltage output from the comparison unit and feeds back the analog / digital converter of the controller. The method of claim 1, wherein the comparison unit, A transfer voltage control circuit which subtracts the amplified voltage from the constant voltage, In a printer comprising a transfer roller, a method for controlling a transfer voltage supplied from a power supply unit under control of a control unit to perform a transfer step of transferring a toner to a paper during a print job: A transfer voltage supply step of supplying a transfer voltage to the transfer roller; A feedback voltage sensing step of sensing a voltage fed back in inverse proportion to the supplied transfer voltage; An amplifying step of amplifying the sensed feedback voltage; A constant voltage supplying step of supplying a constant voltage maintaining a constant level; A comparison step of comparing the supplied constant voltage and the amplified voltage; And, And filtering the noise to remove noise from the subtracted voltage and feeding back the filtered voltage to an analog / digital converter of the controller. The method of claim 3, wherein the comparing step, And subtracting the amplified voltage from the constant voltage.