KR20060019379A - Malfunction diagnosis device and method of optical scanning unit - Google Patents

Abstract

Disclosed is a failure diagnosis apparatus and method for an optical scanning unit. The failure diagnosis apparatus of the optical scanning unit is a optical scanning unit configured to allow a plurality of rotating multi-faceted mirrors to be rotated by one driving motor, and selectively selects one of Y, M, C, and K video data based on a selection signal. A selection unit for outputting an optical path for detecting a horizontal synchronization signal; A synchronization signal detector for sequentially detecting a horizontal synchronization signal of the Y, M, C, and K video data provided through an optical path for detecting the horizontal synchronization signal; An optical output detector for detecting an optical output of each laser diode corresponding to Y, M, C, and K video data; And a controller configured to generate the selection signal and determine whether the optical scanning unit is malfunctioning and a component in which the malfunction occurs based on the output of the synchronization signal detector and the light output detector.

Description

Apparatus and method of diagnozing malfunction in laser scanning unit

1 is a perspective view showing a light scanning unit to which the malfunction diagnosis apparatus according to the present invention is applied;

2 is a block diagram showing the configuration of an embodiment of a malfunction diagnosis apparatus according to the present invention;

3 is a block diagram showing the configuration of an optical output detector in FIG. 2;

4 is a waveform diagram illustrating the operation of each unit shown in FIG. 3, and

5 is a flowchart illustrating an operation of an embodiment of a malfunction diagnosis method according to the present invention.

<Description of the symbols for the main parts of the drawings>

110, 240 ... light generator 111 ... light source

112 ... collimated lens 120 ... first lens

130 ... rotating face mirror 140 ... second lens

150 ... drive motor 160, 250 ... sync signal detector

170 ... Photosensitive drum 210 ... Video controller

220 ... Selection 230 ... Control                 

260 ... density detector 270, 310 ... light output detector

280 ... Display 320 ... Amplifier

330 ... Comparison

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an apparatus and method for accurately diagnosing malfunctions and components causing malfunctions in an optical scanning unit.

In general, the printing process of a laser printer, which is a representative example of an image forming apparatus employing a transfer photograph developing method, is as follows. First, when the charging roller rotated by the high voltage charging voltage rotates the photosensitive member applied on the outer circumferential surface of the photosensitive drum, the light generated from the laser scanning unit is printed on the surface of the photosensitive drum. Forms an electrostatic latent image. On the other hand, a potential difference is generated between a supply roller applied with a high pressure supply voltage and a developing roller applied with a developing high pressure having a lower level than the supply roller. Therefore, the negative charge moves from the feed roller to the developing roller. In this way, the toner supplied from the developing roller is applied to an electrostatic latent image formed on the surface of the photosensitive drum to form a visible image. The transfer roller subjected to the high pressure transfer high pressure transfers the visible image applied on the surface of the photosensitive drum to the printing paper. The visible image transferred to the printing paper is fixed to the printing paper by the high heat and pressure of the heating roller and the pressing roller formed in the fixing machine, thereby completing the printing process. At this time, the supply voltage, the developing voltage, the transfer voltage and the charging voltage are continuously supplied to the supply roller, the developing roller, the transfer roller, and the charging roller, respectively, until the printing operation is completed. The heating roller in the fixing unit is then turned on until the printing operation is completed.

However, in such a laser printer, malfunctions of the optical scanning unit frequently occur such that the density of the developing image is reduced or the color of the developing image is not properly produced. The malfunction of the optical scanning unit may include a failure of a laser diode serving as a light generating unit or a failure of a main board including a video controller. However, the current system cannot accurately determine whether the laser diode is defective or the main board is defective when the optical scanning unit is malfunctioning, thus wasting parts by replacing all parts related to the image, for example, the laser diode and the main board. There is a drawback to this. Alternatively, in the case of malfunction of the optical scanning unit, the user needs to check the density and color of the developing image alternately by alternately replacing the laser diode and the main board. have.

An object of the present invention is to provide a malfunction diagnosis apparatus and method for accurately diagnosing a malfunction and a component causing a malfunction in an optical scanning unit.

Another technical problem to be achieved by the present invention is to provide a malfunction diagnosis apparatus and method for informing a user by accurately diagnosing a malfunction and a component causing a malfunction in an optical scanning unit.

In order to achieve the above technical problems, the apparatus for diagnosing malfunction of a optical scanning unit according to the present invention is a optical scanning unit configured such that a plurality of rotating multi-faceted mirrors can be rotated by one driving motor, and based on a selection signal, Y, M A selector for selectively outputting one of C, K video data to an optical path for detecting a horizontal synchronization signal; A synchronization signal detector for sequentially detecting a horizontal synchronization signal of the Y, M, C, and K video data provided through an optical path for detecting the horizontal synchronization signal; An optical output detector for detecting an optical output of each laser diode corresponding to Y, M, C, and K video data; And a controller configured to generate the selection signal and determine whether the optical scanning unit malfunctions and a component in which the malfunction occurs based on the output of the synchronization signal detector and the light output detector.

In order to achieve the above technical problem, a method for diagnosing malfunction of a light scanning unit according to the present invention is a light scanning unit configured to rotate a plurality of rotating multi-faceted mirrors by a single driving motor, and (a) detecting a horizontal synchronizing signal. Sequentially detecting horizontal sync signals of Y, M, C, and K video data provided through an optical path, and determining whether horizontal sync signals are detected in each video data; (b) determining that there is an abnormality in the video data when the horizontal synchronization signal is not detected in at least one or more pieces of video data as a result of the determination in step (a); And (c) when the horizontal synchronization signal is detected in all of the Y, M, C, and K video data as a result of the determination in step (a), each laser diode corresponding to the Y, M, C, and K video data. Determining whether or not the abnormality.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a light scanning unit to which a malfunction diagnosis apparatus according to the present invention is applied, and is configured such that a plurality of rotating multi-faceted mirrors can be rotated by one driving motor.

Referring to Figure 1, the light generating unit 110 for emitting parallel light, the first lens 120 for focusing the light in the sub-scanning direction, the rotating multi-faceted mirror 130 for deflecting the light in the main scanning direction, The second lens 140, which focuses the light deflected by the rotating multi-faceted mirror 130 on the photosensitive member surface, which is the scanning target surface, has four colors of Y (yellow), M (magenta), C (cyan), and K (black). Are arranged in the sub-scanning direction in correspondence with the. Here, the first lens 120 and the second lens 140 are actually formed by integrally forming four lenses. In recent years, with the development of optical element manufacturing technology, the manufacturing method of the lens has changed from the method of cutting optical materials such as glass to the method of manufacturing by injection molding using optical materials made of transparent plastic. Therefore, it is possible to integrally shape each of the four first lenses 120 and the second lenses 140 arranged in the sub-scanning direction. At this time, it is preferable to form the cylindrical lens and the F-theta lens shape only in the portion where light is transmitted. This significantly reduces the parts cost and the assembly cost as compared to the case of separately manufacturing.

The light generating unit 110 includes a light source 111 and a collimating lens 112, and generally uses a laser diode emitting monochromatic light as the light source 111. Since the light emitted from the light source 111 is divergent light, it passes through the collimated lens 112 to produce parallel light. The first lens 120 focuses the parallel light scanned from the light generating unit 110 in the sub-scanning direction so that the first lens 120 is incident on the rotating multifaceted mirror 130. A first cylindrical lens 120 generally uses a cylindrical lens.

Four rotating multi-faceted mirrors 130 are stacked and installed in the sub-scanning direction on the rotation shaft of the drive motor 150. When the driving motor 150 rotates, the four rotating multi-faceted mirrors 130 are rotated at the same time. At least one reflective surface is formed on the rotating polygon mirror 130 and six reflective surfaces are formed on the rotating polygon mirror 130 according to the present embodiment. As the rotating polygon mirror 130 rotates, the angle between the reflecting surface and the incident light incident from the light generating unit 110 changes continuously, and the reflected light is deflected in the main scanning direction to the photosensitive drum 170. As such, since the four rotating multi-faceted mirrors 130 are rotated by one driving motor 150, unlike the conventional optical scanning unit that must each have four motor drivers to drive four driving motors, one All you need is a motor driver (not shown).

The second lens 140 is installed between the photosensitive drum 170 and the rotating polygon mirror 130. The second lens 140 is an aspherical lens, commonly referred to as an f-theta lens (f-θlens), and allows the light deflected by the rotating polygon mirror 130 to be focused on the surface of the photosensitive drum 170. When passing through the second lens 140, the light deflected by the rotating polygon mirror 130 is imaged on the surface of the photosensitive drum 170 positioned at the focal length regardless of the deflection angle.

The synchronization signal detection unit 160 is usually made of a photodiode, and is for detecting a horizontal synchronization signal in the main scanning direction to match the main scanning start point. That is, when the synchronization signal detection unit 160 starts to scan the light corresponding to the image information after a predetermined time elapses after the light is detected, the light is accurately scanned at the main scanning start point. The synchronization signal detection unit 160 is assembled so that the reflective surfaces of the plurality of rotating multi-faceted mirrors 130 coincide with each other in the sub-scanning direction, so that only one of them is installed, and on the optical path for K (black) video data, A horizontal synchronous signal is detected from a light beam reflected from a located reflection mirror (not shown).

By such a configuration, the parallel light emitted from the light generating unit 110 is focused in the sub-scanning direction by the first lens 120 and is incident on the rotating polygon mirror 130. As the rotating mirror mirror 130 rotates, the light reflected from the reflecting surface is deflected by a predetermined angle range in the main scanning direction, and is focused in the sub-scanning and main scanning directions by the second lens 140 to the photosensitive drum 170 surface. Is injected.

2 is a block diagram showing the configuration of an embodiment of a malfunction diagnosis apparatus according to the present invention, and includes a video controller 210, a selector 220, a controller 230, a light generator 240, and a synchronization signal detector 250. ), The concentration detector 260, the light output detector 270, and the display unit 280.

Referring to FIG. 2, the video controller 210 displays black (K: black), cyan (C: cyan), magenta (M: magenta), and yellow (Y: yellow) video data, respectively, to form a color image. The selector 220 and the light generator 240 are provided at the same time.

The selector 220 selects one of the Y, M, C, and K video data provided from the video controller 210 according to the selection signals S0 and S1 output from the controller 230 and generates the light generator 240. Is provided by one of four laser diodes. Preferably, each of the Y, M, C, and K video data is sequentially provided as a laser diode for K video data. For example, Y video data if S0 and S1 are both '0', M video data if '1' and '0', C video data if '0' and '1', and K video data if both are '1'. Select and print. Accordingly, light beams corresponding to Y, M, C, and K video data are sequentially output along the optical path for the K video data through the laser diode for the K video data.

The controller 230 diagnoses a malfunction of the optical scanning unit according to the density value of the developing image provided at the time of initialization of the image forming apparatus or at the predetermined period from the density detection unit 260, and routines for accurately determining the component causing the malfunction. Is to run. To this end, the controller 230 outputs the selection signals S0 and S1 to the selector 220 at a set time point. When the malfunction diagnosis apparatus according to the present invention is performed at the time of initializing the image forming apparatus, the controller 230 is based on the output of the synchronization signal detector 250 and the light output detector 270, and the video controller 210 or the light generator It is determined whether the malfunction of the 240 and the component that is defective during the malfunction. On the other hand, the malfunction diagnosis apparatus according to the present invention determines the defective component when the density value of the developed image provided from the concentration detection unit 260 is less than a predetermined reference value, that is, performed when the malfunction. If it is determined that the video controller 210 has an abnormality, the controller 230 displays on the display unit 280 so that the user can replace the video controller 210. On the other hand, if it is determined that there is an error in the laser diode, the controller 230 displays the laser diode in which the error occurs on the display unit 280. On the other hand, if it is determined that a defect occurs in the video controller 210 or the laser diode, the controller 230 controls the power supply unit (not shown) to stop the operation of the image forming apparatus.

The light generator 240 generates light having intensity corresponding to Y, M, and C video data provided from the video controller 210 and K video data provided from the selector 220. The light corresponding to the Y, M, C, and K video data is simultaneously generated through the corresponding laser diode for the effective picture section, but for the non-picture section, K according to the selection signals S0 and S1 provided from the controller 230. It occurs sequentially through the laser diode for video data.

The synchronization signal detector 250 sequentially detects the horizontal synchronization signal from the light beam corresponding to the Y, M, C, and K video data generated through the optical path corresponding to the K video data, and transmits the detection result to the controller 250. to provide.

The concentration detector 260 detects the concentration of the developed image at predetermined time intervals and provides it to the controller 230 in order to determine whether the development is performed properly.

The light output detector 270 detects the light output provided from each of the four laser diodes, and provides the detection result to the controller 230. In an embodiment, the synchronization signal detector 270 and the light output detector 270 may be operated at the same time to provide the detection result of each unit to the controller 230. In another exemplary embodiment, when the video signal controller 210 is determined to be normal as the sync signal detector 270 operates, the light output detector 270 may be operated. The former is preferable for the initialization of the image forming apparatus, and the latter is preferable at the time of printing operation, that is, when the density of the developed image is below the reference value.

3 is a block diagram illustrating the configuration of the light output detector 270 in FIG. 2, wherein the light output detector 270 includes an amplifier 310 and a comparator 320.

Referring to FIG. 3, first, the light generating unit 240 includes a driving unit 241 and a laser unit (not shown) including a pair of the laser diode D1 and the photodiode D2. The driver 241 provides a current corresponding to the input video data to the laser diode D1, and the photodiode D2 detects the light output of the laser diode D1 and feeds it back to the driver 241 for automatic power control. Enable APC.

The amplifier 310 amplifies the light output detected from the photodiode D2 of the light generator 240 and provides the amplification unit 310 to the comparator 320. The comparator 320 compares the output signal of the amplifier 310 with a predetermined reference value and provides '1' or '0' to the controller 230 according to the comparison result. Here, the reference value is preferably determined based on a predetermined minimum light output, for example, 0.3 mW and the amplification gain of the amplifier 310. The controller 230 detects a laser diode in which a failure occurs according to the signal output from the comparator 320.

In detail, the light output detector 270 detects the light output from the four photodiodes corresponding to the four laser diodes in the light generator 240, and compares the light outputs with a predetermined reference value. As a result of the comparison in the light output detector 270, the controller 230 determines that the laser diode whose light output is equal to or less than a predetermined reference value is the diode in which an abnormality has occurred.

4 is a waveform diagram illustrating the operation of each unit shown in FIG. 3, (a) a horizontal synchronous signal, (b) a sample and hold signal, (c) video data, and (d) an amplification unit ( Each output signal of 310 is shown. Here, T1 represents an effective picture section and T2 represents a non-picture section. T3 denotes a section in which the laser diode D1 is turned on to calibrate the light output by the driver 241, and T4 denotes a section in which the laser diode D1 is turned on to detect the horizontal synchronization signal. That is, when the sample & hold signal b is generated, the automatic power control (APC) operation is performed in the driver 241, and the amplification unit 310 detects the optical output of the laser diode D1 with the photodiode D2. To provide.

5 is a flowchart illustrating an operation of an embodiment of a malfunction diagnosis method according to the present invention.

Referring to FIG. 5, in operation 510, a malfunction diagnosis routine of the optical scanning unit is started. Step 510 is performed when the image forming apparatus is initialized or when the density of the developed image detected by the density detector 260 is equal to or less than a predetermined reference value.

In operation 520, the control unit 230 generates the selection signals S0 and S1 to sequentially generate light beams corresponding to the Y, M, C, and K video data as optical paths for the K video data, and to synchronize the signal detection unit 250. ) Detects a horizontal synchronizing signal from each light beam. When the horizontal synchronous signal is detected from the light beams corresponding to the Y, M, C, and K video data, the video data, that is, the video controller 210 determines that the video signal is normal, and proceeds to step 540.

In operation 530, when the horizontal synchronization signal is not detected in at least one of the light beams corresponding to the Y, M, C, and K video data, an error occurs in the video data, that is, the video controller 210. I think that.

In step 540, when the horizontal synchronization signal is detected from the light beams corresponding to the Y, M, C, and K video data in step 520, the light of each laser diode D1 is passed through the corresponding photodiode D2. Detect the output.

In step 550, the light output of each laser diode detected in step 540 is compared with a predetermined reference value, and when the light outputs of the four laser diodes exceed the reference value, the process returns to step 510.

In step 560, when at least one or more of the light outputs of the four laser diodes in step 550 are less than or equal to the reference value, it is determined that there is an error in the laser diode.

In operation 570, a component in which an abnormality occurs among the video controller 210 and the laser diode is displayed on the display unit 280 such as a liquid crystal panel. At this time, the alarm signal may be generated at the same time.

The above embodiment is performed by first performing a horizontal synchronization signal detection process, and then performing a light output check process of the laser diode, but may be performed in the reverse order or simultaneously.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of a carrier wave (for example, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

As described above, according to the present invention, when an image deterioration occurs due to poor optical scanning, the laser diode and the video controller detect a part in which a malfunction has occurred and notify the user of this, thereby preventing indiscriminate parts replacement. . In addition, by stopping the operation of the image forming apparatus when the malfunction of the component is detected, it is possible not only to cope with the failure quickly but also to prevent unnecessary power consumption.

Although the present invention has been described with reference to the above embodiments, it is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. will be. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

In the optical scanning unit configured to be rotated by a plurality of rotating multi-faceted mirror in one drive motor, A selector configured to selectively output one of Y, M, C, and K video data to an optical path for detecting a horizontal synchronization signal based on the selection signal; A synchronization signal detector for sequentially detecting a horizontal synchronization signal of the Y, M, C, and K video data provided through an optical path for detecting the horizontal synchronization signal; An optical output detector for detecting an optical output of each laser diode corresponding to the Y, M, C, and K video data; And And a control unit for generating the selection signal and determining whether the optical scanning unit malfunctions and a component in which the malfunction occurs based on the output of the synchronization signal detector and the light output detector. Diagnostic device. The device of claim 1, wherein the device is As a result of the determination by the control unit, the malfunction diagnosis device of the optical scanning unit, characterized in that it further comprises a display unit for displaying whether the malfunction of the optical scanning unit and the component in which the malfunction occurred. The method of claim 1, wherein the light output detection unit An amplifier for amplifying an optical output of each laser diode corresponding to the Y, M, C, and K video data; And And a comparing unit comparing the light output of each of the amplified laser diodes with a predetermined reference value, and providing a comparison result to the control unit. In the optical scanning unit configured to be rotated by a plurality of rotating multi-faceted mirror in one drive motor, (a) sequentially detecting horizontal sync signals of Y, M, C, and K video data provided through an optical path for detecting the horizontal sync signals, and determining whether horizontal sync signals are detected in each video data; (b) determining that there is an abnormality in the video data when the horizontal synchronization signal is not detected in at least one video data; And (c) determining whether an abnormality of each laser diode corresponding to the Y, M, C, and K video data is detected when horizontal synchronization signals are detected in the Y, M, C, and K video data. Method for diagnosing malfunction of optical scanning unit. The method of claim 4, wherein step (c) An optical scanning unit, characterized in that the optical output of each laser diode corresponding to the Y, M, C, K video data is compared with a predetermined reference value, and the laser diode having an optical output less than or equal to the reference value is determined to have an abnormality. How to diagnose malfunction.

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