KR100230316B1 - Method of synchronizing the start of laser scanning and apparatus of the same - Google Patents

Abstract

Disclosed are a method for synchronizing optical scanning of a printer and an apparatus thereof. The method of synchronizing the optical scanning of the printer includes a optical scanning unit for scanning light in the main scanning direction, the width direction of the photosensitive belt circulating in one direction along the longitudinal direction, and the optical scanning unit on the opposite side of the optical scanning unit with the photosensitive belt as the center. A printer including a photodetector for outputting an electrical signal corresponding to incident light and an optical path directed toward the edge of the photosensitive belt out of the light emitted from the unit to the light receiving window, and a printing machine including a system controller for controlling the driving of the photoreceptor unit. Set a reference line parallel to the longitudinal direction of the photosensitive belt on the photosensitive belt, and measure the horizontal distance to the edge of the reference line in a predetermined interval along the reference line and measure the horizontal distance or the horizontal distance. It is converted into the time required for the light to be scanned to progress and stored, and from the photodetector Synchronization start time of optical scanning for writing image information of the optical scanning unit is made based on the completion of the period in which the required time corresponding to the horizontal distance of the position of the scanning line of light is added to the time when the output signal of the pulse on Let's do it. According to the optical scanning system to which this method is applied, the scanning tip in the image information recording area can be matched without being affected by defects and curvatures of the photosensitive belt edge line.

Description

Synchronization method of photowangju period of printing press and its device

The present invention relates to a method and a device for synchronizing optical scanning of a printing press. Specifically, the scanning start timing in the main scanning direction can be matched to the image information writing area regardless of defects and curvatures of the photosensitive belt edge. It relates to a method for synchronizing optical scanning time of a printing press and a device therefor.

1 is a cross-sectional view showing a general electrophotographic printing press.

Referring to the drawings, the reset device 15 and the color are sequentially arranged on the movement path of the photosensitive belt 14, which is a photosensitive medium driven forward by three rollers 11, 12, 13 arranged in a triangle shape. A plurality of optical yarn unit 30, a developing device 20, a drying device 24, and a transfer device 25 are provided.

Looking at the printing process, first, the optical scanning unit 30 scans the light corresponding to the image input to the photosensitive belt 14 orbiting through the reset device (15). Through this process, the electrostatic latent image is formed on the photosensitive belt 14. A transfer roller 26 which rotates in contact with the photosensitive belt 14 after forming an image by injecting a toner or a developer in a liquid state into a solid developing material onto the photosensitive belt 14 having an electrostatic latent image formed thereon; The desired image can be printed by passing the paper 28 between the pressing rollers 27 which pressurizes it.

2 is a perspective view showing the optical scanning system of FIG.

Referring to the drawings, the optical scanning system has a main optical unit and the photodetector 34 as a main element. The optical fiber unit 30 has a light source 31, a rotating mirror 32, and a lens unit 33 as main elements to scan light in the main scanning direction, the width direction of the photosensitive belt 14, which is driven forward in the direction of the arrow. Have

Here, the scanning direction perpendicular to the traveling direction of the photosensitive belt 14, that is, the width direction of the photosensitive belt 14 is the main scanning direction, and the direction perpendicular to the main scanning direction, that is, the traveling direction of the photosensitive belt 14 is the sub scanning direction. This is called. A photodetector arranged to receive a portion of the light traveling out of the image information writing area D from the light source 31 so that the scanning tip thereof is parallel to the image information writing area D of the photosensitive belt 14. The start signal in the main scanning direction is synchronized using the output signal of (34).

The photodetector 34 is arranged such that the edge line of the photosensitive belt 14 is located at the center of the incident window. Therefore, the light is incident on the incident window of the photodetector 34 only until a predetermined period before entering the photosensitive belt 14 among the light sequentially scanned in the main scanning direction. The system controller 35 determines the fall time of the pulse signal inputted by the photodetector 34 as the edge detection time of the photosensitive belt 14 as it rises and falls with a predetermined width according to incident light. After the light output is delayed by a time corresponding to the distance to), the light source 31 is driven to emit an optical signal corresponding to the image.

However, the edge line of the manufactured photosensitive belt 14 has a curvature or edge because it is driven to emit an optical signal from the light source 31 after a time set on the basis of the falling time of the pulse signal output from the photodetector 34. In the case where there are some missing defects, the tips of the light scanned in the image information recording area D along the sub-scanning direction do not coincide. As a result, matching of the scanning tip depends on the degree of straightness of the edge line of the photosensitive belt.

SUMMARY OF THE INVENTION The present invention was devised to improve the above problems, and is not influenced by defects and straightness of the photosensitive belt edge line, and the optical scanning synchronization of the printer can match the leading edge during scanning in the image information writing area. Its purpose is to provide a method and an apparatus thereof.

1 is a cross-sectional view showing a general printing press,

2 is a perspective view showing the optical scanning system of FIG.

3 is a perspective view showing a light scanning system according to the present invention,

4 is a waveform diagram illustrating an output waveform of some elements in order to explain the optical scanning synchronization method of the optical scanning system of FIG. 3.

<Description of the reference numerals for the main parts of the drawings>

11, 12, 13: roller 14, 46: photosensitive belt

15: reset device 20: developer

24: drying apparatus 25: transfer apparatus

26: transfer roller 27: pressure roller

28: Paper 30: Gwangju company unit

31, 41: light source 32, 42: rotating face mirror

33, 43: lens unit 34, 44: photodetector

35, 49: system control unit 45: light receiving window

47: memory 48: horizontal synchronization signal generator

50: reference line 51: edge

In order to achieve the above object, the optical scanning device synchronous method of the printing machine according to the present invention has a center of the optical scanning unit and the photosensitive belt for scanning light in the main scanning direction, which is the width direction of the photosensitive belt circulating in one direction along the longitudinal direction. The photodetector and the photoreceptor unit, which are arranged so that the optical path of the light emitted from the photoreceptor unit from the opposite side of the photoreceptor unit toward the edge of the photosensitive belt is directed toward the light receiving window, and outputs an electrical signal corresponding to the incident light. A method for synchronizing optical scanning of a printing machine having a system control unit for controlling the driving of a light source, the method comprising: setting a reference line parallel to the longitudinal direction on the photosensitive belt, and determining a horizontal distance to the edge with respect to the reference line. The horizontal distance or the image being scanned, measured at regular intervals along the line A period in which light is converted into a time required to advance the horizontal distance and stored, and the required time corresponding to the horizontal distance of the scan line position of the light is added at the time when the output signal of the pulse from the photodetector is completed. The reference point is characterized in that the optical scanning start time for synchronizing the optical scanning unit for image information is synchronized.

In addition, in order to achieve the above object, the optical scanning system of the printing machine according to the present invention is mainly based on the optical scanning unit and the photosensitive belt for scanning light in the main scanning direction of the width direction of the photosensitive belt circulating in one direction along the longitudinal direction Gwangju of the printing machine having a photodetector for outputting an electrical signal corresponding to the incident light is disposed so that the light path toward the edge of the photosensitive belt out of the light emitted from the Gwangju company unit on the opposite side of the Gwangju company unit In the yarn system, the horizontal line or the horizontal by setting a reference line parallel to the longitudinal direction on the photosensitive belt, by measuring the horizontal distance to the edge with respect to the reference line in a predetermined interval along the reference line The time taken for the scanned light to travel along the distance is shown in the table. Stored memory; Horizontal synchronizing which outputs the time extended by the required time corresponding to the horizontal distance of the position of the scanning line of the light as a reference time point for scanning synchronization when the output signal of the pulse from the photodetector is completed. And a system control unit for instructing the start of optical scanning for writing image information of the optical scanning unit after a predetermined time on the basis of the signal input informing the reference time point from the horizontal synchronous signal generating unit. It is done.

Hereinafter, a method and an apparatus for synchronizing optical scanning time of an electrophotographic printer according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a perspective view showing a light scanning system according to the present invention.

Referring to the drawings, a rotating multi-face mirror 42 is provided which deflects the light incident on the front of the light source 41 that emits light in the main scanning direction. A lens unit 43 for adjusting the optical path is provided between the rotary polygon mirror 42 and the photosensitive belt 46. The photodetector 44 is arranged behind the photosensitive belt 46 such that the edge line of the photosensitive belt 46 is located at the center of the incident window 45. Here, the light source 41, the rotating mirror 42 and the lens unit 43 is included in the optical scanning unit.

The memory 47 has a horizontal distance r to the edge 51 with respect to the reference line 50 set on the photosensitive belt 46 in accordance with the optical isochronous synchronization method of the present invention along the reference line 50, and the like. The horizontal distance r measured at the interval p or the data converted into the time required for the light to be scanned to travel the horizontal distance r are stored.

Therefore, in the memory 47, data converted into a horizontal distance r corresponding to each position on the photosensitive belt 46 or a time taken for the light to travel through the horizontal distance r to the table table is stored. It is stored.

Then, according to the optical scanning optical synchronization method of the present invention, the timing at which the output signal of the pulse from the photodetector 44 is completed is determined as the detection time of the edge 51 of the photosensitive belt 46, from which the edge 51 is detected. Is the optical distance for writing the image information of the light source 41 when the stored distance from the reference line 50 to the reference line 50, i. It is set as the reference point for synchronizing the start time. In other words, the reference point 50 is synchronized with the reference time point at which light reaches the reference line 50, and is delayed by a time corresponding to the distance a from the reference line 50 to the image information recording area D. After that, the optical scanning is started. To this end, the horizontal synchronizing signal generator 48 provides the information about the reference time in a form that the system controller 49 can know.

The horizontal synchronous signal generator 48 determines whether the edge of the photosensitive belt 14 is to be detected as the edge of the photosensitive belt 14 when the falling time of the pulse signal inputted by the predetermined width is raised and lowered according to the incident light from the photodetector 44. The horizontal distance r corresponding to the position on the photosensitive belt 46 which is coupled with the scanning line to which the current light is scanned in advance in the memory 47 or the time required to start inputting the pulsed signal from The data is read and extended to the system controller 48 by the required time corresponding to the horizontal distance r read at the time of completion of the pulse signal, that is, at the time of falling. Here, the positional information of the photosensitive belt 46 from which light is scanned can be obtained from the system controller 48.

The system controller 49 controls the entire system, and controls and judges the progress of the photosensitive belt 46, and after a predetermined time on the basis of the falling time of the pulse signal output from the horizontal synchronous signal generator 48, 41) to start optical scanning for image information writing. Here, the delay time between the falling time of the pulse signal output from the horizontal synchronizing signal generator 48 and the start of optical scanning corresponds to the distance a between the set image information recording area D and the reference line 50. .

Although not shown, a collimating lens for converting a diverging light beam incident in parallel between the light source 41 and the rotating mirror mirror 42, and a cylinder to direct the light beam in the main scanning direction and to converge the light beam in the sub-scan direction. Curl lenses and the like are disposed on the optical path. A rotating motor 42 having a plurality of reflective surfaces is provided with a drive motor (not shown), and the rotational drive of the drive motor is controlled by the system controller 45. The rotation of the rotating polygon mirror 42 changes the angle of the incident light beam with respect to the reflecting surface, so that the light reflected from each reflecting surface is periodically deflected.

The lens unit 43 has at least one f-θ lens, compensates the optical path difference according to the optical path of each light beam deflected by the rotating polygon mirror 42, and focuses the incident light beam on the main scanning line.

Hereinafter, the operation will be described with reference to FIGS. 3 and 4.

The light emitted from the light source 41 is scanned in the main scanning direction via the rotating mirror mirror 42 and the lens unit 43. At this time, the optical path is sequentially changed along the main scanning direction from the right side away from the cell belt 46 by a predetermined distance by the rotating multi-face mirror 42 rotated at a constant speed. The light incident on the light receiving window 45 of the photodetector is blocked from traveling to the photodetector 44 at the moment reaching the edge 50 of the photosensitive belt 46 along the scanning line. At this moment, the pulse signal generation from the photodetector 44 to the horizontal synchronous signal generator 48 is completed. On the other hand, the horizontal synchronous signal generator 48, in which the photodetector 44 receives the pulse signal from the beginning of light reception, continuously outputs the pulse signal, and is coupled to the scan line to which the current light is scanned in the memory 47. Pulse width by the required time d corresponding to the horizontal distance r read at the completion of the pulse signal, i. Is output to the system control unit 49. The system controller 49 stops the driving of the light source 41 when the pulse signal starts to be input, and if the input pulse signal falls, the distance from the falling point to the reference line 50 and the image information recording area D After counting the set time T corresponding to (a), the light source 41 is driven to generate an optical signal corresponding to the image information. If it rotates during this period, the mirror 42 is rotated at a constant speed.

Therefore, the scanning opening tip in each reflective surface of the rotating mirror mirror 42 which is continuously rotated coincides with the front end of the image information recording area D without being affected by the straightness of the edge of the photosensitive belt 46.

As described so far, the method and apparatus for synchronizing the optical scanning time of the printing press according to the present invention can match the scanning tip in the image information recording area without being affected by defects and curvature of the photosensitive belt edge line. .

Claims (3)

Of the photosensitive belt out of the light emitting unit from the optical scanning unit from the opposite side of the optical scanning unit centered on the photosensitive belt and the optical scanning unit for scanning light in the main scanning direction, the width direction of the photosensitive belt circulating in one direction along the longitudinal direction An optical path synchronizing method of a printing press having a photo detector arranged to face an edge of an optical path and outputting an electrical signal corresponding to an incident light, and a system controller for controlling driving of the optical scanning unit. , The horizontal line or the light being scanned is measured by setting a reference line parallel to the longitudinal direction on the photosensitive belt and measuring a horizontal distance to the edge with respect to the reference line in a predetermined interval along the reference line. In terms of the time it takes to advance the horizontal distance, save Write image information of the optical scanning unit with reference to the completion time of the period in which the required time corresponding to the horizontal distance of the position of the scanning line of the light is added to the time when the output signal of the pulse from the photodetector is completed. Gwangju period synchronous method of the printing press, characterized in that for synchronizing the start time of optical scanning. Of the photosensitive belt out of the light emitting unit from the optical scanning unit from the opposite side of the optical scanning unit centered on the photosensitive belt and the optical scanning unit for scanning light in the main scanning direction, the width direction of the photosensitive belt circulating in one direction along the longitudinal direction An optical scanning system of a printing machine comprising a photodetector arranged to face an edge of the light path toward the light receiving window and outputting an electrical signal corresponding to the incident light, The reference line parallel to the longitudinal direction is set on the photosensitive belt, and the horizontal distance to the edge with respect to the reference line is measured in a predetermined interval along the reference line to scan the horizontal distance or the horizontal distance. A memory in which a time taken for the light to proceed is stored in a table table; Horizontal synchronizing which outputs the time extended by the required time corresponding to the horizontal distance of the position of the scanning line of the light as a reference time point for scanning synchronization when the output signal of the pulse from the photodetector is completed. A signal generator; And And a system control unit for instructing the start of optical scanning for writing image information of the optical scanning unit after a predetermined time on the basis of the signal input informing the reference time point from the horizontal synchronous signal generating unit. system. The method of claim 2, wherein the horizontal synchronous signal generating unit outputs the pulse signal of the photodetector as it is and extends the width of the output pulse by the required time corresponding to the horizontal distance. The system control unit is configured to instruct the start of optical scanning for writing the image information of the optical scanning unit after a predetermined time on the basis of the falling time of the pulse signal output from the horizontal synchronous signal generating unit .

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