KR20000038464A - Optical scanning system of a printer - Google Patents

Abstract

PURPOSE: An optical scanning system of a printer is provided to suppress scanning error by generating synchronous signals for line scan initiation continuously. CONSTITUTION: An optical scanning system of a printer includes an optical scanning unit(50), a first optical detector(45), a second optical detector(47), and an optical scanning controller(60,70). The optical scanning unit(50) emits light along with a main scan direction crossing the direction of a rotating photosensitive belt(44) with a predetermined angle. The first optical detector(45) detects the emitted light from the optical scanning unit(50) at a position displaced from the photosensitive belt(44) with a predetermined spacing to an edge of the photosensitive belt. The second optical detector(47) detects the light from the optical scanning unit prior to the first optical detector. The optical scanning controller(60,70) controls the optical scanning unit so that the unit emits light corresponding to image information in the direction of the main scan direction.

Description

Optical scanning system of the printing press

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scanning system of a printing press, and more particularly, to a light scanning system of a printing press which suppresses an image information scanning error by not missing a line scanning start synchronization signal.

1 shows an optical scanning system of a conventional printing press.

Referring to the drawings, the optical scanning system has a photosensitive unit 20 for scanning light to the photosensitive belt 14 circulated by the plurality of rollers (11, 12, 13), and out of the photosensitive belt (14). The photodetector 15 and the photodetector 15 arranged to detect light emitted from the position between the edges of the photosensitive belt 14 receive a pulse signal output in response to light reception. The optical scanning controller 30 is provided to control the optical scanning.

The optical scanning control unit 30 outputs light corresponding to the actual image information into the image information recording area D set in the photosensitive belt 14 in synchronization with the pulse output from the photodetector 15 in response to the photodetection. To control the photowangsa unit 20 to be.

Referring to the operation, first, the optical scanning control unit 30 is a time when the light received from the optical scanning unit 20 to the end of the light receiving end of the pulse signal received from the photodetector 15 arrived at the edge of the photosensitive belt 14 Judging by. Then, the light output is stopped for the time required for light to be scanned from the edge of the photosensitive belt 14 to the image information recording area D, and then the light source 21 is driven to emit light corresponding to the image information. Let's do it.

In the conventional optical scanning system operated as described above, if the photosensitive belt 14 is deviated a lot in the width direction from the set track with respect to the photodetector 15 having a light receiving area of an appropriate size in consideration of the price, the photodetector 15 The light receiving region of may be covered by the photosensitive belt 14. In addition, the joint 14a of the photosensitive belt 14 having an irregular shape may cover the light receiving area of the photodetector 15.

In this case, the pulse signal corresponding to the light emitted toward the photodetector 15 is not output from the photodetector 15. Therefore, if the pulse which should be output from the photodetector 15 every line scanning period is omitted due to the above-mentioned cause, the optical scanning control unit 30 still has the output light still at the edge of the photosensitive belt 14. It is judged that it has not arrived at, and continues to drive the light source 21 so that light is emitted until a pulse signal is input. As a result, an unwanted line-shaped electrostatic latent image is formed on the photosensitive belt 14 by the light emitted continuously. In this way, the omission of the pulse signal by shielding the light-receiving area of the photodetector 15 causes an image information writing error.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a light scanning system of a printing press that suppresses an image information scanning error by preventing the occurrence of a signal for synchronizing a line scanning initiation every line scanning cycle. .

1 is a view showing a conventional optical scanning system of the printing press,

2 is a view showing the optical scanning system of the printing press of an embodiment according to the present invention,

3 is a signal waveform diagram of some elements of FIG. 2;

4 is a view showing the optical scanning system of the printing machine of another embodiment according to the present invention,

5 is a waveform diagram of some elements of FIG. 4.

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

11, 12, 13, 41, 42, 43: roller 14, 44: photosensitive belt

15: photodetector 20, 50: Gwangju company unit

21, 51: light source 30, 60, 70: optical scanning control unit

45: first photodetector 46, 47: second photodetector

52: rotating face mirror 53: lens unit

54: motor

61: edge error detection window signal generator

62, 72: auxiliary line synchronization signal generator

63, 73: line scan synchronization signal generator 64, 74: Gwangju unit drive unit

65, 75: edge position memory

In order to achieve the above object, the optical scanning system of the printing machine according to the present invention comprises: a optical scanning unit for emitting light with respect to the photosensitive belt along a main scanning direction intersecting at a predetermined angle with respect to the traveling direction of the photosensitive belt in circular motion; A first photodetector provided to detect light emitted from the photoreceptor unit toward an edge of the photosensitive belt from a position away from the photosensitive belt by a predetermined distance; A second photodetector installed to receive light emitted from the photowangsa unit along the main scanning direction before the first photodetector; The optical scanning unit to emit light corresponding to the image information along the main scanning direction from the tip of the image writing area set on the photosensitive belt using the signals output from the first photodetector and the second photodetector The optical scanning control unit for controlling the optical scanning control unit; is provided.

Preferably, the optical scanning controller comprises: an edge error detection window signal generator for outputting a window signal having a predetermined width in synchronization with a second light reception signal output from the second photodetector; An auxiliary line synchronization signal generator for outputting an auxiliary line synchronization signal if a first light reception signal corresponding to light reception is not input from the first photodetector during the window signal generation period; When the first light receiving signal is input, a line scan synchronizing signal is output after a first time set based on an end point of the first light receiving signal, and when the auxiliary line synchronizing signal is input, the line scanning synchronizing after a predetermined time. A line scan synchronization signal generator for outputting a signal; And a light scanning unit unit driving the light scanning unit so that light corresponding to the image data is emitted when the line scanning synchronization signal is input. The apparatus may further include an edge position storage unit configured to count and store a time until the reception end point of the first light reception signal based on the second light reception signal, and wherein the line scan synchronization signal generation unit is input to the auxiliary line synchronization signal. The line scan synchronization signal is output after a time obtained by subtracting the window generation time from the time stored in the edge position storage unit and the first time through internal calculation.

Alternatively, the optical scanning system of the printing machine according to the present invention includes a optical scanning unit for emitting light to the photosensitive belt along the main scanning direction intersecting at a predetermined angle with respect to the traveling direction of the photosensitive belt in a circular motion; A first photodetector provided to detect light emitted from the photoreceptor unit toward an edge of the photosensitive belt from a position away from the photosensitive belt by a predetermined distance; A second photodetector provided to receive light emitted from the photoreceptor unit toward between the first photodetector and the image writing area of the photosensitive belt; The optical scanning unit to emit light corresponding to the image information along the main scanning direction from the tip of the image writing area set on the photosensitive belt using the signals output from the first photodetector and the second photodetector The optical scanning control unit for controlling the optical scanning control unit; is provided.

The optical scanning controller generates an auxiliary line synchronization signal for outputting an auxiliary line synchronization signal in synchronization with a second light reception signal output from the second light detector when a first light reception signal corresponding to light reception is not input from the first light detector. Wealth; When the first light receiving signal is input, a line scan synchronizing signal is output after a first time set on the basis of an end point of the first light receiving signal. A line scan synchronization signal generator for outputting the line scan synchronization signal after time; When the line scan synchronization signal is input, a light scanning unit unit for driving the light scanning unit so that the light corresponding to the image data is emitted; preferably. The apparatus may further include an edge position storage unit configured to count and store a time from when light reception ends of the first light reception signal to the light reception start time or the light reception end time of the second light reception signal, and the line scan synchronization signal generation unit is further configured. When the synchronization signal is input, the line synchronization signal is output after a time obtained by subtracting the time stored in the edge position storage unit from the first time through an internal operation.

Hereinafter, an optical scanning system of a printing press according to preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing an optical scanning system of the printing press of an embodiment according to the present invention.

Referring to the drawings, the optical scanning system includes a optical scanning unit 50, the first photodetector 45, the second photodetector 46, the optical scanning control unit 60.

The optical scanning unit 50 scans light in the main scanning direction orthogonal to the traveling direction of the photosensitive belt 44 circulated by the plurality of rollers 41, 42, 43. The optical fiber unit 50 includes a light source 51 for emitting light, a rotating polyhedron 52 rotated by a motor 54, and a lens unit 53 for focusing light with the photosensitive belt 44. . Alternatively, the optical fiber unit 50 may include a light source and a scan disk (not shown). The scan disk is formed with a hologram pattern to deflect the incident light beam along the scanning direction by rotation.

The first photodetector 45 is opposite to the photosensitive belt unit 50 around the photosensitive belt 44, and moves toward the edge of the photosensitive belt 44 from a position away from the photosensitive belt 44 by a predetermined distance. ) To detect the light emitted.

The second photodetector 46 may receive the light receiving area earlier than the first photodetector 45 of the light emitted from the optical scanning unit 50 along the main scanning direction without interfering with the photosensitive belt 44. It is installed.

The optical scanning control unit 60 outputs the received light signal from the first photodetector 45 without dropping to synchronize the emission of the light corresponding to the image data from the tip of the image writing area D set on the photosensitive belt 44. When the first photodetector 45 is synchronized with the line scanning using the first light reception signal output corresponding to the light reception, when the first light signal is missing, the second light reception output from the second photodetector 46 Synchronize the line scan using the signal. The configuration of the optical scanning control unit 60 for controlling the driving of the optical scanning unit 50 by the line scanning synchronizing method is possible by various methods, and the illustrated figure shows an example thereof.

The illustrated scanning control unit 60 includes an edge error detection window signal generation unit 61, an auxiliary line synchronization signal generation unit 62, a line scan synchronization signal generation unit 63, and a scanning unit unit 64. Equipped.

The edge error detection window signal generator 61 outputs a window signal having a predetermined width in synchronization with the second light reception signal output in response to the light reception from the second light detector 46. The width of the window signal is less than the time required to deflect the light from the time of generating the second light receiving signal to the image writing area D on the photosensitive belt 44, and the first light detector 45 at the time of generating the second light receiving signal. It is appropriately set within a range larger than the time required to deflect the light to the light receiving region of the light.

The auxiliary line synchronizing signal generator 62 generates an auxiliary line synchronizing signal for synchronizing the line scan when the first light receiving signal is missing. The auxiliary line synchronization signal generator determines whether the first light reception signal corresponding to the light reception is input from the first light detector 45 during the window signal generation period, and when the first light reception signal is not inputted, the auxiliary line synchronization signal having a predetermined width. Output the signal.

When the first scan signal corresponding to the light reception is input from the first photodetector 45, the line scan synchronization signal generator 63 receives the line scan synchronization signal after the first time set based on the end point of the first light reception signal. Outputs The first time is directed toward the tip of the image writing area D set on the photosensitive belt 44 on the basis of the end point of the first light receiving signal corresponding to the time when the light scanned at the edge of the photosensitive belt 44 arrives. Corresponds to the time until you can exit.

On the other hand, the line scan synchronizing signal generator 63 outputs the line scan synchronizing signal after a predetermined time when the auxiliary line synchronizing signal is inputted from the auxiliary line synchronizing signal generator 62 due to the missing first light receiving signal. The delay time until the line scan synchronizing signal is generated based on the auxiliary line synchronizing signal input is based on the image writing set on the photosensitive belt 44 at the point of occurrence of the second light receiving signal when the photosensitive belt 44 circulates in the normal track. There is a method of applying the window signal generation time by subtracting the time from the time until the light can be emitted toward the tip of the area (D), but preferably the photosensitive belt 44 is separated from the normal orbit To some extent, the delay time until the line scan sync signal is generated based on the auxiliary line sync signal input is adjusted. To this end, when the position of the photosensitive belt 44 corresponding to the track departure is determined, the received signal from the first photodetector 45 is not omitted so that the timing of generating the line scanning synchronization signal for the auxiliary line synchronization signal can be adjusted. An edge position storage section 65 is further provided for counting and storing the pulse width count value of the first light reception signal or the time from the second light reception signal to the end point of the first light reception signal. The edge position storing unit 65 updates and stores the time counted from the second light receiving signal to the end point of the first light receiving signal every line.

When the edge position storing unit 65 counts and stores the time from the second light receiving signal to the end of the first light receiving signal, when the auxiliary line scanning synchronizing signal is input, the line scanning synchronizing signal generating unit 63 performs an edge position. The line scan synchronizing signal is generated after the time obtained by subtracting the window generation time from the time stored in the storage unit 65 and the first time. When the auxiliary line scan synchronization signal is input as a pulse signal having a predetermined width, and the reference point of the termination of the auxiliary line scan synchronization signal is used as a reference, the line scan synchronization signal generator 63 is stored in the edge position storage unit 65. The line scan synchronization signal may be generated after a time obtained by subtracting the window generation time and the auxiliary line scan synchronization signal holding time from the time plus the first time.

In this way, if the time stored in the edge position storage unit 65 just before the first light reception signal is missed is used to adjust the line scan synchronization signal generation timing, the second light reception signal is generated based on the occurrence of the second light reception signal even when the first light reception signal is missing. The time until the line scan synchronizing signal is generated is equal to the time until the line scan synchronizing signal is generated based on the generation of the second light receiving signal when the first light receiving signal is generated.

The optical scanning unit driver 64 drives the optical scanning unit 50 to emit light corresponding to the image data in synchronization with the line scanning synchronization signal output from the line scanning synchronization signal generator 63. After the light source unit driver 64 controls the light corresponding to a line of image data to be emitted in the image information writing area D, the light receiving position of the second light detector 46 is independent of the image information writing. When it is time to emit light, the light source 51 is briefly driven to obtain the first and second light receiving signals.

The signal waveform of the operation relationship of the optical scanning control unit 60 is shown in FIG. Referring to FIG. 3, the window signal W is generated when the second light receiving signal P2 is input from the second light detector 46, and the first light receiving signal is input within the window signal generation period Tw. When the auxiliary line synchronization signal is not generated, the line scan synchronization signal generator 63 outputs the line scan synchronization signal after the first time Tf set after the light reception end point of the first light reception signal P1. The optical scanning unit driver 64 starts emitting light corresponding to the image data in synchronization with this line scanning synchronization signal. On the other hand, the time Ts until the end point of the first light reception signal P1 is counted and stored in the edge position storage unit 65 on the basis of the input time of the second light reception signal P2.

When the optical scanning unit 50 scans one line and then emits light to the start position of the next scanning line, the second light receiving signal P2 is output from the second light detector 46. Then, when the first light receiving signal P1 is not input during the window signal W holding period, the auxiliary line synchronization signal generator 62 outputs the auxiliary line synchronization signal P3. As such, when the first light receiving signal P1 is omitted and the auxiliary line synchronization signal P3 is input, the line scan synchronization signal generator 63 is edged by internal calculation based on the end point of the auxiliary line synchronization signal P3. Time obtained by subtracting the window generation time Tw and the auxiliary line synchronization signal holding time Tp from the time Ts + Tf plus the time Ts stored in the position storage unit 65 and the first time Tf. After ({Ts + Tf}-{Tw-Tp}), a line scan synchronization signal is generated. Accordingly, when the time Ts stored just before the first light reception signal is missed is used to adjust the generation timing of the line scan synchronization signal, the generation of the second light reception signal P2 is referred to even when the first light reception signal P1 is missed. Therefore, the time T until the line scan synchronization signal is generated is equal to the time T until the line scan synchronization signal is generated based on the generation of the second light reception signal P2 when the first light reception signal P1 is generated. You lose. As such, even when the first light receiving signal P1 is omitted, the edge position information of the photosensitive belt 44 corresponding to the pulse width value T1 of the first light receiving signal P1 previously counted using the second light receiving signal P2 is obtained. By utilizing this to generate a line scan synchronization signal, an error in writing an image into the image writing area D is reduced.

Figure 4 shows a light scanning system of a printing press of another embodiment according to the present invention. Elements having the same function as in the above-described drawings are denoted by the same reference numerals.

Referring to FIG. 3, unlike in FIG. 3, the second light detector 47 emits the first light of the light emitted from the optical scanning unit 50 along the main scanning direction without interfering with the light receiving area of the photosensitive belt 44. It is provided in the position which can receive the light which goes to between the detector 45 and the image-writing area | region D set in the photosensitive belt 44. As shown in FIG.

The optical scanning control unit 70 receives the received signal from the first light detector 45 so as to synchronize the emission of light corresponding to the image data from the tip of the image writing area D set on the photosensitive belt 44 as described above. When not outputted, the line scan is synchronized using the first light receiving signal output from the first photodetector 45 when outputted. When the first light receiving signal is omitted, the line scanning is synchronized using the second light receiving signal output from the second light detector 47.

The optical scanning control unit 70 includes an auxiliary line synchronizing signal generator 72, a line scanning synchronizing signal generator 73, and a optical scanning unit driver 74.

When the first light receiving signal is not input, the auxiliary line synchronization signal generator 72 determines whether the first light receiving signal corresponding to the light receiving is input from the first light detector 45 before the second light receiving signal is input. The auxiliary line synchronization signal having a predetermined width is output in synchronization with the second light receiving signal.

When the first light receiving signal corresponding to the light reception is input from the first light detector 45, the line scan synchronizing signal generator 72 receives the line scanning synchronizing signal after the first time set based on the end point of the first light receiving signal. Outputs The first time is directed toward the tip of the image writing area D set on the photosensitive belt 44 on the basis of the end point of the first light receiving signal corresponding to the time when the light scanned at the edge of the photosensitive belt 44 arrives. Corresponds to the time until you can exit.

On the other hand, the line scan synchronizing signal generator 73 outputs the line scan synchronizing signal after a predetermined time when the auxiliary line synchronizing signal is input from the auxiliary line synchronizing signal generator 72 due to the missing first light receiving signal. The delay time until the line scan synchronizing signal is generated based on the auxiliary line synchronizing signal input is based on the image writing set on the photosensitive belt 44 at the point of occurrence of the second light receiving signal when the photosensitive belt 44 circulates in the normal track. There is a method in which the time until the light can be emitted toward the tip of the area D is set in advance, but preferably, the auxiliary line synchronous signal is compensated for the deviation of the photosensitive belt 44 from the normal orbit. Adjust the delay time until the line scan sync signal is generated based on the input. To this end, it is preferable that the edge position memory unit 75 is further provided as described above.

The edge position storage unit 75 calculates the time from when the first light reception signal is not received from the first light detector 45 to the light reception start time or the light reception end time of the second light reception signal. Count and save.

When the edge position storage unit 75 is further provided as described above, when the auxiliary line synchronization signal inputs the auxiliary line synchronization signal, the line scan synchronization signal generator 73 enters the edge position storage unit 75 at the first time through internal operation. The line scan synchronization signal is output after the time obtained by subtracting the stored time. In this way, if the time stored and counted from the end of the first light receiving signal to the time of input of the second light receiving signal immediately before the first light receiving signal is omitted in the edge position storage unit 75 is used for adjusting the line scan synchronization signal generation time, Even when the first received signal is omitted, the time until the line scan synchronization signal is generated based on the generation of the second received signal and the current line scan synchronization signal is generated based on the generation of the second received signal when the first received signal is generated immediately. Since the time becomes the same, the error of the timing of generating the line scan synchronization signal is reduced.

The optical scanning unit driver 74 drives the optical scanning unit to emit light corresponding to the image data in synchronization with the line scanning synchronization signal output from the line scanning synchronization signal generator.

The signal waveform of the operation relationship of the optical scanning controller 70 is shown in FIG. 5, only the case where the first light receiving signal is missing will be described. The edge position memory unit 75 counts and stores the time t1 until the light receiving end point of the second light receiving signal P2 is counted based on the light receiving end point of the last first light receiving signal P1 before being omitted. .

After the light source unit 50 scans one line and then emits light to the start position of the next scan line, the first light signal P1 is not output from the first light detector 45 and the second light is not output. When the second light receiving signal is input from the detector 47, the auxiliary line synchronizing signal generator 72 outputs the auxiliary line synchronizing signal P3 in synchronization with the light receiving end point of the second light receiving signal P2. As such, when the first light receiving signal P1 is omitted and the auxiliary line synchronization signal P3 is input, the line scan synchronization signal generator 72 may generate a first reference signal based on an input point of the auxiliary line synchronization signal P3. The line scan synchronizing signal is generated after the time Tf-t1 obtained by subtracting the time t1 stored in the edge position storage unit 75 from one hour Tf.

As described so far, according to the optical scanning system of the printing press according to the present invention, since the line scanning synchronizing signal is generated irrespective of the deviation of the orbit of the photosensitive belt, the image writing error can be reduced.

Claims (6)

A photowangsa unit for emitting light to the photosensitive belt along the main scanning direction intersecting at a predetermined angle with respect to the traveling direction of the photosensitive belt in a circular motion; A first photodetector provided to detect light emitted from the photoreceptor unit toward an edge of the photosensitive belt from a position away from the photosensitive belt by a predetermined distance; A second photodetector installed to receive light emitted from the photowangsa unit along the main scanning direction before the first photodetector; The optical scanning unit to emit light corresponding to the image information along the main scanning direction from the tip of the image writing area set on the photosensitive belt using the signals output from the first photodetector and the second photodetector Optical scanning control unit for controlling the optical scanning system; optical scanning system of the printing machine comprising a. The method of claim 1, The optical scanning controller An edge error detection window signal generator for outputting a window signal having a predetermined width in synchronization with a second light reception signal output from the second photodetector; An auxiliary line synchronization signal generator for outputting an auxiliary line synchronization signal if a first light reception signal corresponding to light reception is not input from the first photodetector during the window signal generation period; When the first light receiving signal is input, a line scan synchronizing signal is output after a first time set based on an end point of the first light receiving signal, and when the auxiliary line synchronizing signal is input, the line scanning synchronizing after a predetermined time. A line scan synchronization signal generator for outputting a signal; And a light scanning unit unit for driving the light scanning unit so that the light corresponding to the image data is outputted when the line scanning synchronization signal is input. The method of claim 2, An edge position storage unit for counting and storing the time until the light receiving end point of the first light receiving signal based on the second light receiving signal is further provided, When the auxiliary line synchronization signal is input, the line scan synchronization signal generation unit scans the line after the time obtained by subtracting the window generation time from the time stored in the edge position storage unit and the first time through internal calculation. Optical scanning system of the printing press, characterized in that for outputting a synchronization signal. A photowangsa unit for emitting light to the photosensitive belt along the main scanning direction intersecting at a predetermined angle with respect to the traveling direction of the photosensitive belt in a circular motion; A first photodetector provided to detect light emitted from the photoreceptor unit toward an edge of the photosensitive belt from a position away from the photosensitive belt by a predetermined distance; A second photodetector provided to receive light emitted from the photoreceptor unit toward between the first photodetector and the image writing area of the photosensitive belt; The optical scanning unit to emit light corresponding to the image information along the main scanning direction from the tip of the image writing area set on the photosensitive belt using the signals output from the first photodetector and the second photodetector Optical scanning control unit for controlling the optical scanning system; optical scanning system of the printing machine comprising a. The method of claim 4, wherein The optical scanning controller An auxiliary line synchronization signal generator for outputting an auxiliary line synchronization signal in synchronization with a second light reception signal output from the second light detector when a first light reception signal corresponding to light reception is not input from the first light detector; When the first light receiving signal is input, a line scan synchronizing signal is output after a first time set on the basis of an end point of the first light receiving signal. A line scan synchronization signal generator for outputting the line scan synchronization signal after time; And a light scanning unit unit for driving the light scanning unit so that the light corresponding to the image data is outputted when the line scanning synchronization signal is input. The method of claim 5, An edge position storage unit for counting and storing the time from the light receiving end time of the first light receiving signal to the light receiving start time or the light receiving end time of the second light receiving signal is further provided. And the line scan synchronizing signal generator outputs a line scan synchronizing signal after a time obtained by subtracting the time stored in the edge position storage unit from the first time through an internal operation when the auxiliary line synchronizing signal is input. Of optical yarn system.