KR19990067631A - System for polymerizing chromatographic images on photoconductor belts - Google Patents

Abstract

A system for polymerizing chromatographic images on a photoconductor belt 12 of an imaging system 76 operative to detect edge positions of the photoconductor belt 12. The polymerization system detects the position using the same laser scanner used to form a latent image on the photoconductor belt. The polymerization system includes a belt steering control system 103 that steers the photoconductor belt 12 based on the detected position to reduce the deviation of the belt from the continuous conveying path. The polymerization system may also include a scan control system 88 that controls the modulation of the laser beam scanned based on the detected position to form a latent image on the photoconductor belt 12. By controlling the belt steering 103 and the laser beam scanning 88, the polymerization system maintains the image quality of the final multicolor image when transmitting the polymerized color separation image to the output medium.

Description

System for polymerizing chromatographic images on photoconductor belts

In a multicolor photoelectric imaging system, a latent image is formed in the imaging region of a moving photoconductor. Each latent image represents one image of a plurality of different color separation images. The color separation images are combined with each other to represent a full multicolor image. The color separation image may represent, for example, yellow, magenta, cyan, and black components that produce a visual representation of a multicolor image in a subtractive combination on the output medium. Prior to the imaging cycle, a constant charge is applied to the surface of the photoconductor. Each latent image is formed by scanning a modulated laser beam across a moving photoconductor to selectively discharge an image-wise pattern of photoconductor. After each latent image is formed, an electrostatic radiator of that color is applied to the photoconductor to electrostatically radiate the latent image. The final color separation image is finally sent to the output medium to form a multicolor image.

In some photoelectric imaging systems, a latent image is formed and electrostatically radiated on top of another of the common imaging area of the photoconductor. The latent image can be formed and electrostatically radiated by multiple passes of the photoconductor around the continuous transfer path. Alternatively, the latent image may be formed and electrostatically radiated by a single pass of the photoconductor around the continuous transport path. The single pass system allows multicolor images to be assembled at very high speeds.

In the photoelectric imaging system as described above, the latent image must be formed by accurate polymerization of another latent image to produce a high quality image. In a system using a photoconductor belt, accurate polymerization is not easy due to the deviation of the belt from the transport path in a direction perpendicular to the transport path. In particular, the photoconductor belt is prone to lateral movement during movement. The image region in which the latent image is formed is fixed relative to the edge of the photoconductor belt. However, the scanning beam used to form each latent image in the image area is fixed with respect to the scanning start coordinates. Lateral motion of the photoconductor belt may cause image area movement relative to the scanning start coordinate. As a result, mispolymerization may occur between different scanning lines and between different latent images. This mispolymerization can significantly reduce image quality. In particular, the mispolymerization may generate arch artifacts that appear in the final multicolor image when the mispolymerized color separation image is transmitted to the output medium.

FIELD OF THE INVENTION The present invention relates to multicolor imaging, and more particularly to a technique for polymerizing one or more color separation images on a photoconductor belt.

1 is a schematic diagram conceptually illustrating a typical photoelectric imaging system.

2 is a plan view of a typical photoconductor belt used in the photoelectric imaging system of FIG. 1.

3 is a functional block diagram illustrating a system for polymerizing one or more chromatographic images on a photoconductor belt, in accordance with the present invention.

4 is a schematic diagram illustrating an example of a belt edge detector for use in a polymerization system, in accordance with the present invention.

5 is a flow diagram illustrating the operation of an exemplary belt edge detection process performed by a polymerization system, in accordance with the present invention.

6 is a side view of an exemplary photoconductor belt device using a belt steering control system useful in a polymerization system, in accordance with the present invention.

FIG. 7 is a bottom perspective view of the photoconductor belt device of FIG. 6. FIG.

8A is a front view of a belt steering mechanism useful in the belt steering control system of FIG.

8B is a plan view of the belt steering mechanism of FIG. 8B.

The present invention relates to a system for polymerizing one or more color resolution images on a photoconductor belt. The polymerization system operates to detect the position of the edge of the photoconductor belt using the same laser scanner used to form a latent image on the photoconductor belt. In this manner, the polymerization system detects the deviation of the photoconductor belt from the continuous transport path. The polymerization system includes a belt steering control system that steers the photoconductor belt based on the detected position to reduce the deviation of the belt from the continuous transfer path. The polymerization system may also include a scan control system that controls the modulation of the laser beam scanned based on the detected position to form a latent image on the photoconductor belt. By controlling belt steering and laser beam scanning, the polymerization system maintains the image quality of the final multicolor image when transferring the polymerized color separation image to the output medium.

1 is a schematic diagram conceptually illustrating a typical photoelectric imaging system 10. In the example of FIG. 1, the imaging system 10 includes a plurality of rollers 14, 16, 18, an eraser 20, a charging unit 22, a plurality of scanners 24, 26, 28, 20, and a plurality of scanners. Electrostatic radiation sections 32, 34, 36, 38, a drying section 40 and a photoconductor belt 12 installed around the transmission section 42. Imaging system 10 forms a multicolor image by passing photoconductive belt 12 once around a continuous transfer path. In operation of the system 10, the photoconductor belt 12 is driven to move in a first direction indicated by arrow 44 along a continuous transfer path. When the photoconductor belt 12 moves along the transfer path, the eraser 20 uniformly discharges any charge remaining on the belt resulting from the previous image operation. Subsequently, the photoconductor belt 12 meets the charging section 22, which fills the belt uniformly to a predetermined level. The scanners 24, 26, 28, 30 selectively discharge the image region of the photoconductor belt 12 with each laser beam 46, 48, 50, 52 to form an electrostatic latent image. Each latent image represents one of a plurality of color separation images.

As shown in FIG. 1, each electrostatic radiation portion 32, 34, 36, 38 is disposed behind each scanner 24, 26, 28, 30 with respect to the direction of movement 44 of the photoconductor belt 12. . Each electrostatic copy unit 32, 34, 36, 38 is applied to an electrostatic copier having a unique color for the color separation image represented by the particular latent image formed by the preceding scanners 24, 26, 28, 30. In the example of FIG. 1, the electrostatic radiation units 32, 34, 36, 38 apply yellow, magenta, cyan and black electrostatic copiers to the photoconductor belt 12, respectively.

If the photoconductor belt 12 continues to move in the direction 44, the subsequent scanners 26, 28, 30 are formed by the preceding scanner and the latent image electrostatically radiated by the preceding electrostatic copying portions 32, 34, 36. Disclosed is a work of forming a latent image in an image region of polymerization with a polymer. Thus, color-separated images are formed in polymerisation portions on different tops in the same image area. The scanners 24, 26, 28, 30 and the electrostatic copying portions 32, 34, 36, 38 may be spaced apart so that the entire latent image is formed before the subsequent latent image formation and the electrostatic radiation. However, as the speed increases and the size decreases, each of the scanners 26, 28, 30 and the electrostatic copying portions 34, 36, 38 starts the formation of the subsequent latent image and the electrostatic radiation before the formation of the preceding latent image and the electrostatic radiation. It is good to be.

After the scanners 24, 26, 28, 30 and the electrostatic copying portions 32, 34, 36, 38 form a latent image and electrostatically copy the image area of the moving photoconductor belt 12, the drying portion 40 Meet with The drying section 40 may include a heated roller 54 forming a nip with the belt roller 18. The heated roller 54 heats the photoconductor belt 12 to dry the electrostatic radiator applied by the electrostatic radiators 32, 34, 36, 38. The image region of the photoconductor belt 12 then reaches the transmission section 42. The transfer section 42 includes an intermediate transfer roller 56 forming a gap with the photoconductor belt 12 on the belt roller 14 and a press roller 58 forming a gap between the intermediate transfer roller. The electrostatic copier on the photoconductor belt 12 is moved from the photoconductor belt surface to the intermediate transfer roller 56 by a selective adhesive force. The pressure roller 58 serves to transmit the image on the intermediate transfer roller 56 to the output medium 60 by applying pressure and / or heat to the output medium. The output medium 60 may include paper or film, for example.

FIG. 2 is a plan view of a typical photoconductor belt 12 used in the photoelectric imaging system 10 of FIG. 1. As shown in FIG. 2, the photoconductor belt 12 includes a belt left side 12 and a belt right side 64. Photoconductor belt 12 also includes an imaging region 66. The image area 66 includes a left margin 68 located at a fixed distance with respect to the belt left side 62 and a right margin 70 located at a fixed distance with respect to the belt right side 64. ). The left margin 68 and the right margin 70 delimit the width of the image region 66 extending in a direction perpendicular to the direction of motion 44 of the photoconductor belt 12. The image area 66 also has a length that is not shown in FIG. 2 but is bounded by upper and lower margins.

Each scanner 24, 26, 28, 30 is oriented to scan each laser beam 46, 48, 50, 52 across the width of the image area 66 of the scan line. As the photoconductor belt 12 moves in the direction 44 for each scanner 24, 26, 28, 30, a plurality of scan lines are created on the belt. The laser beam is modulated based on the image data representing the latent image such that each scan line includes an image scan segment. The image scan segment extends between the left margin 68 and the right margin 70, and may merge together to form a latent image in the image area 66. The first belt edge 62 and the second belt edge 64 preferably extend parallel to the direction of motion 44 of the photoconductor belt 12. However, as indicated by dashed lines 72 and 74, the photoconductor belt 12 can move to both sides while maintaining some deviation from the transfer path while moving in the direction 44.

In order to produce a high quality image, the latent image formed by the scanners 24, 26, 28, 30 must be formed by accurate polymerization with other latent images of the image area 66. Accurate polymerization can be difficult due to the lateral motion of the photoconductor belt 12 during movement. The left margin 68 and the right margin 70 of the image region 66 are fixed relative to the left side 62 and the right side 64 of the photoconductor belt 12, respectively. In contrast, image scan segments and scan lines of scanners 24, 26, 28, and 30 are generally fixed relative to scan start coordinates. Lateral motion of the photoconductor belt 12 may cause the image region 66 to move relative to the scan start coordinates. As a result, mispolymerization can occur between different scan lines and between different latent images. This mispolymerization significantly degrades the image quality. In particular, the mispolymerization may generate an arch fact that is visually visible in the final multicolor image when the mispolymerized color separation image is transmitted to the output medium 60.

According to the present invention, a system is provided for polymerizing chromatographic images on the photoconductor belt 12. The polymerization system of the present invention operates to detect the position of the edge of the photoconductor belt 12. Based on the detected position, the polymerization system can perform two different functions to ensure accurate polymerization of the color separation images. First, the polymerization system includes a belt steering control system that steers the photoconductor belt 12 based on the detected position to reduce the deviation of the belt from the continuous transfer path. Secondly, the polymerization system may further include a scan control system that controls the laser beams 46, 48, 50, 52 scanned by the scanners 24, 26, 28, 30 based on the detected position. In particular, the scan control system uses each laser beam 46, based on the detected position, to start each image scan segment at a fixed distance relative to one of the sides 62, 64 of the photoconductor belt 12. 48, 50, 52) to control the modulation. By controlling belt steering and laser beam scanning, the polymerization system of the present invention maintains the image quality of a multicolor image when transferring the polymerized color separation image to an output medium.

In the example of FIG. 1, the imaging system 10 is a four color imaging system. However, the polymerization system of the present invention can also be readily applied to provide any number of polymerizations of one or more latent images on the photoconductor belt. In addition, although the imaging system 10 is shown in FIG. 1 as a multicolor / single pass system, the polymerization system of the present invention is readily applied to a multipass electrophotographic imaging system requiring common polymerization of color separated images on a photoconductor. Can be. In a multipass imaging system, the lateral motion of the photoconductor belt usually tends to be periodic. Thus, mispolymerization between successive latent images may be more predictable than in a single pass system. Nevertheless, the polymerization system according to the invention is useful in multipass systems for improving image quality.

3 is a functional block diagram illustrating an exemplary embodiment of a system 76 for polymerizing chromatographic images on a photoconductor belt 12 according to the present invention. In the example of FIG. 3, the polymerization system 76 includes a scanner 24, 26, 28, 30, a computer 78, a plurality of laser drivers 80, 82, 84, 86, a scanner control and synchronization module 88. ), One or more belt edge detectors 92, 94, 96, 98, a controller 100, a belt edge synthesizing device 102, and a belt steering controller 103. The polymerization system 76 of FIG. 3 provides polymerization of color separation images relative to the sides of the moving photoconductor belt 12. In the example of FIG. 3, polymerization system 76 provides polymerization to the left edge 62. However, the polymerization may be performed with respect to the right side 64.

According to the invention, each scanner 24, 26, 28, 30 is a laser beam of scan line traversing the photoconductor belt 12 and across the belt edge detection region adjacent the left edge 62 of the photoconductor belt ( 46, 48, 50, 52). The belt edge detection area may be disposed adjacent to the right belt edge 64. A portion of each belt edge detector 92, 94, 96, 98 is disposed in the belt edge detection area. The laser beams 46, 48, 50, 52 scanned by each scanner 24, 26, 28, 30 perform a dual function. In particular, the laser beams 46, 48, 50, 52 are used to form a latent image on the photoconductor belt 12, and the left edge 62 is formed by the belt edge detectors 92, 94, 96, 98. It is also used to facilitate the detection of. The scanners 24, 26, 28, 30 advantageously provide an inexpensive and accurate light source for use in belt edge detection processes. The laser beam scanned by the scanners 24, 26, 28, 30 allows detection of belt edge motion of a size smaller than the pixel size. Belt detection can also be synchronized with respect to the pixel clock used for scanning. The scanners 24, 26, 28, 30 scan the laser beams 46, 48, 50, 52 on a "full-time" basis. Thus, even if the laser beams 46, 48, 50, 52 emitted by the particular scanners 24, 26, 28, 30 are not modulated to form a latent image, the scanner will still have to Scan the laser beam. The scan line provided by each scanner 24, 26, 28, 30 extends perpendicular to the direction of movement 44 of the photoconductor belt. Movement of the photoconductor belt 12 in the direction 44 perpendicular to the scan line produces a plurality of scan lines across the photoconductor belt. Each scan line 24, 26, 28, 30 is, for example, a laser diode emitting a laser beam 46, 48, 50, 52, scanning for scanning the laser beam across the photoconductor belt 12. Mechanism, and optics for focusing the laser beam onto the photoconductor belt. The scanning mechanism may include, for example, a multi-facet mirror controlled by a scan drive motor.

Instead of using the scanners 24, 26, 28, 30 for belt edge detection, one or more additional scanners may be installed and dedicated for belt edge detection. However, the use of scanners 24, 26, 28, and 30 for both image and belt edge detection is very cost effective, less complex, and facilitates synchronization of belt edge detection with an image scanning process. Alternatively, a self-scanning pixel array can be used instead of photo diodes. The magnetic scan type pixel array does not require the use of a scanner 24, 26, 28, 30 or a dedicated belt edge detection scanner for the light source. The magnetic scan type pixel array is generally effective for detecting belt edge motion, but may not provide a detection resolution on the order of the detection resolution provided by the scan type laser beam. The pixel array also increases the cost and complexity of the overall imaging system. Nevertheless, a dedicated scanner or magnetic scan type pixel array may be suitable for some applications.

The computer 78 according to the invention serves as a first scan controller which forms part of a scan control system. The computer 78 is configured by each scanner 24, 26, 28, 30 based on the image data to form a latent image in the image region 66 of the photoconductor belt 12 having a plurality of image scan segments. Modulate the laser beam to be scanned. Each image scan segment forms part of one of the scan lines. Computer 78 modulates the laser beam through laser drivers 80, 82, 84, 86, as indicated by line 104. Laser diode drivers 80, 82, 84, 86 drive the input of the laser diode associated with each scanner 24, 26, 28, 30, as indicated by lines 106, 108, 110, 112. The computer 78 modulates the laser beam to initiate each image scan segment at a particular point along the scan line. Referring to FIG. 2, each image scan segment preferably starts at the left margin 68 of the image area for accurate polymerization.

Scanner control and synchronization module 88 controls the scanning mechanism associated with each scanner 24, 26, 28, 30, as indicated by line 114. In particular, the scanner control and synchronization module 88 controls the scanning speed of each scanning mechanism and provides phase synchronization between the scanning mechanisms associated with the various scanners 24, 26, 28, 30. The scanner control and synchronization module 88 also generates an image scan start signal for each scanner, as indicated by line 116. The image start signal provides the computer 78 with a start indication of each image scan segment relative to the scan start coordinates. The computer 78 scans the laser beams 46, 48, scanned by the scanners 24, 26, 28 30 in response to the image scan start signal to start the image scan segment at a suitable point for the start of each scan line. 50, 52) to control the modulation.

4 is a schematic diagram illustrating an example of one of the belt edge detectors 92, 94, 96, 98. As shown in FIG. 4, the belt edge detector 92 is disposed adjacent the left edge 62 of the photoconductor belt 12 and is on the side of the photoconductor belt opposite the scanner 24. 120). As also shown in FIG. 4, scanner 24 scans laser beam 46 via photoconductor belt 12 and photodetector 120 of the scan line. The photodetector 120 is positioned in alignment with the scan line 24 with respect to the direction of motion 44 of the photoconductor belt 12 to receive the laser beam in a portion of the scan line 124. Optical means in the form of a correction prism 126 is disposed between the scanner 24 and the photodetector 120. The correction prism 126 is also disposed between the scanner 24 and the photoconductor belt 12. The correction prism 126 overlaps the photodetector 120 and the left belt edge 62 and allows the laser beam 46 to be projected onto the photodetector and left belt edge substantially perpendicular to the photoconductor belt 12. The correction prism 126 receives the laser beam at a point above the photoconductor belt 12, thereby preventing the laser beam from being blocked in advance by the left edge 62 resulting from the vertical movement of the belt. The correction prism 126 thus ensures that this vertical motion is not incorrectly detected as the lateral motion of the photoconductor belt 12.

The photodetector 120 of each belt edge detector may include an optical diode having an active region 128 that overlaps the left edge 62 of the photoconductor belt 12. The optical diode is sensitive to the wavelength of the laser beam scanned by the scanner 24. The non-overlapping portion of the active region 128 occupies the belt edge detection region adjacent to the left edge 62. The degree of overlap varies with the degree of lateral movement of the left edge 62. Thus, the width of the active region 128 should be large enough to overlap the left edge 62 to at least some extent over the full range of lateral motion of the photoconductor belt 12. An example of a suitable optical diode is an OSD 60-3T optical diode manufactured and sold by Centronics, Newbury Park, California.

In the photodetector 120 of each belt edge detector 92, 94, 96, 98, the laser beams 46, 48, 50, 52 from the adjacent scanners 24, 26, 28, 30 have a belt edge of the photodetector. The belt edge detection signal is generated when scanning across the detection area. In this exemplary embodiment, each belt edge detector 92, 94, 96, 98 continues to generate a belt edge detection signal until a laser beam is projected onto the left edge 62 of the photoconductor belt 12. . Alternatively, each belt edge detector 92, 94, 96, 98 may be disposed adjacent to the right belt edge 64. As shown in FIG. 4, the photodetector 120 may include a reference mask 130 positioned over an edge of the active region 128. Reference mask 130 provides the correct edge, as indicated by reference numeral 132, at which point photodetector 120 first receives laser beam 46. When the laser beam 46 is projected onto the active region 128 adjacent to the reference mask 130, the belt edge detection signal transitions from the first amplitude to the second amplitude. The belt edge detection signal is in a second amplitude state until the laser beam 46 is projected onto the left edge 62 indicated by reference numeral 134. When the laser beam 46 is projected onto the left side portion 62, the photoconductor belt 12 prohibits the laser beam from being projected onto the photodetector 120. As a result, the belt edge detection signal transitions from the second amplitude to the first amplitude. Thus, the position of the belt edge 62 determines the duration of the second amplitude belt edge detection signal. Conversely, the duration of the second amplitude belt edge detection signal provides an indication of the position of the belt edge 62.

Referring back to FIG. 3, each belt edge detector 92, 94, 96, 98 transmits a belt edge detection signal to the belt edge synthesizer 102, as indicated by line 136. In this example, the belt edge synthesizer 102 operates as a second scan controller that cooperates with the controller 100, the scanner control and synchronization module 88, and the computer 78 to form part of the scan control system. The belt edge synthesizer 102 also operates in cooperation with the belt steering controller 103 to form part of the belt steering control system as described below in this description. The second scan controller is coupled to at least one belt edge detector 92, 94, 96, 98 to initiate each image scan segment at a substantially fixed distance with respect to the left edge 62 of the photoconductor belt 12. Modulation of the laser beams 46, 48, 50, 52 scanned by each scanner 24, 26, 28, 30 is controlled based on the belt edge detection signal generated by the scanner. In particular, belt edge synthesizer 102 synthesizes belt edges for each scanner and each scan line indicated by line 138 based on belt edge detection signals received from belt edge detectors 92, 94, 96, 98. The value signal is sent to the scanner control and synthesis module 88. The scanner control and synthesis module 88 generates an image scan start signal for each scanner based on the composite belt edge value signal, and transmits this image scan start signal to the computer 78 as indicated by line 116. do. The computer 78 uses the respective scanners 24, 26, 28, 30 based on the image scan start signal to start each image scan segment at a substantially fixed distance with respect to the left edge 62 of the photoconductor belt 12. Control the timing of the laser beams 46, 48, 50, 52 for the < RTI ID = 0.0 >

The controller 100 may include, for example, a microprocessor or programmable logic circuit. Prior to operation, computer 78 downloads the belt edge protection program to controller 100 as indicated by line 140. Alternatively, the belt detection program may be stored in a nonvolatile memory associated with the controller 100. The controller 100 executes a program to control the operation of the belt edge synthesizer 102. The belt edge synthesizer 102 may include, for example, a plurality of counters. Each counter corresponds to one of the belt edge detectors 92, 94, 96, 98. The controller 100 loads the existing composite belt edge values into each counter as indicated by line 142. The existing composite belt edge value indicates the position of the left edge 62 of the photoconductor belt 12.

Each counter of the belt edge synthesizer 102 generates a belt edge detection signal generated by a corresponding belt edge detector 92, 94, 96, 98 indicating a first projection of the laser beam 46 on the active area 128. Transitions to the second amplitude, the counter value is subtracted one by one from the existing synthetic belt edge value at a known clock speed. The clock speed and composite belt edge value of the counter are determined based on the pixel clock speed and pixel size. In particular, the counter clock speed and the combined belt edge value are preferably set large enough to detect the spatial movement of the photoconductor belt 12 in proportion to the pixel dimensions. As an example, each scan line is formed at 600 pixels per inch (236 pixels per centimeter) at 18 x 10 ⁶ pixel clock speeds per second and the position of the left belt edge 62 is ideally 0.125 inches from the reference mask 130. (0.317 centimeters). To detect spatial movement at a ratio of one sixth of a pixel dimension (0.00028 inches or 0.0007 centimeters), the counter loads 855 as the composite belt edge value and subtracts the value of the counter at a clock speed of 100 MHz.

The counter is the counter value if any of the later happens, when the corresponding belt edge detection signal representing the projection of the laser beam 46 on the left belt edge 62 transitions to a first amplitude or the counter value reaches zero. Stop declining. If the belt edge detection signal transitions to the first amplitude before the counter value reaches zero, the counter continues counting but the counter value at the moment of transition is latched as the actual positional representation of the belt edge 62. After the counter value reaches zero, if the belt edge detection signal transitions to the first amplitude, the counter stops counting and the "wrap-around" count value at the instant of transition is the actual value of the belt edge 62. Form a positional representation. In either case, the final count value indicates the difference between the actual belt edge position and the belt edge position indicated by the composite belt edge value. Belt edge synthesizer 102 provides the controller 100 with counter values resulting from various counters, as indicated by line 144. If the counter value is greater than zero, the left belt edge 62 is moved to the left to some extent. If the counter value is less than zero, that is, the counter cycles to a negative value, the left belt edge 62 has moved to the right to some extent. For accurate polymerization, the image scan segment of the laser beam 46 must shift to the right or left as a function of the actual movement of the left belt edge 62. To determine the amount of shift for the computer 78, the controller 100 generates a new composite belt edge value as indicated by line 142 and sets the counter of the belt edge synthesizer 102 to the new belt edge value. Reload with

The belt edge synthesizer 100 transmits the new composite belt edge value to the scan control and synthesis module 88. The controller 100 and the belt edge synthesizer 102 may generate a composite belt edge value using a single counter based on the belt edge detection signal generated by the single belt detector 92, 94, 96, 98. However, in the example of FIG. 3, four belt edge detectors 92, 94, 96, 98 are located along the length of the photoconductor belt 12 and aligned with each scanner 24, 26, 28, 30. do. The use of four belt edge detectors 92, 94, 96 and 98 facilitates the detection of defects in the left belt edge 62 by comparing with the outputs of the various belt edge detectors. Due to damage during use or incorrect manufacturing, there may be a sawtooth defect along the left belt edge 62. The defect can cause the single belt edge detector to detect the wrong position with respect to the left belt edge 62. In order to avoid false belt edge position detection, it is desirable to filter the belt edge detection signal generated by the defect result. In the example of FIG. 3, the controller 100 processes the counter values generated by the belt edge synthesizer 102 for each belt edge detector 92, 94, 96, 98 to identify signals related to the defect. .

5 is a flow diagram illustrating the operation of a belt edge detection procedure performed by a polymerization system, in accordance with the present invention. FIG. 5 illustrates the operation of the belt edge synthesizer 102, in particular under the control of the controller 100 and the controller 100. As shown in FIG. 5, when the start indicated by block 146 is initiated, computer 78 first initializes system 76 as indicated by block 148. At initialization, computer 78 downloads the belt edge detection program to controller 100 as indicated by line 140 in FIG. Alternatively, the belt edge detection program may reside in a nonvolatile memory associated with the controller 100. As indicated by block 150 in FIG. 5, the controller 100 determines whether the various scanners 24, 26, 28, 30 are in sync with each other. If the scanners 24, 26, 28, 30 are out of sync, the controller 100 waits for it to sync as indicated by loop 152. If the synchronization is correct, the controller 100 determines whether cross-web movement is required, as indicated by block 154. Cross movement refers to movement in the direction perpendicular to the belt 12 movement direction 44. The controller 100 generates images of each scanner 24, 26, 28, and 30 for the cross movement required to correct the spatial misalignment of the reference mask 130 of the belt edge detectors 92, 94, 96, and 98. Add to

The controller 100 can move if necessary by adjusting the composite belt edge value loaded in the counter associated with the particular scanner 24, 26, 28, 30 if correction is needed. If no cross movement is required, the controller 100 does not adjust the existing synthetic belt edge value. However, the controller 100 loads the existing composite belt edge value into the counter of the belt edge synthesizer 102 as indicated by line 156 and block 158. If cross movement is required, the controller 100 adjusts the composite belt edge value to an offset that reflects the degree of movement required to correct, as indicated by block 160. Controller 100 then loads the adjusted composite belt edge value into the corresponding counter of belt edge synthesizer 102 as indicated by line 162 and block 158.

The belt edge synthesizer 102 then waits for the scanners 24, 26, 28, 30 to scan the laser beam 46 across the active region 128 of the photoconductor 120, and block 164, 166. Wait for each counter to produce the final counter value, as indicated by 168,170 and loop 172. When the counter provides the final count value for the scan line, the belt edge synthesizer 102 provides the final count value to the controller 100 as indicated by lines 174, 176, 178, and 180. The controller 100 processes the final count value as indicated by block 182 and determines whether the final count value indicates the movement of the left belt edge 62 as indicated by block 184. The controller 100 determines whether a movement has occurred by comparing the final count value with the existing composite belt edge value. As described above, when the counter value is larger than zero, the left belt edge 62 is moved to the left to some extent. If the counter value is less than zero, that is, the counter has cycled, the left belt edge 62 has moved to the right to some extent. If the counter value is exactly zero, no move occurred. If no movement has occurred, the controller 100 reloads the existing composite belt edge value into the counter as indicated by line 186. The belt edge synthesizer 102 then sends the existing composite belt edge values to scan control and synchronization module 88 as indicated by line 138.

When the controller 100 determines that the left belt edge 62 has moved, the controller 100 filters the value resulting from the belt edge detection signal associated with the defect of the left belt edge as indicated by block 188. The algorithm is applied to the final counter value. The algorithm causes the controller 100 to ignore the belt edge detection signal associated with the defect in order to control the modulation of the laser beam. The algorithm determines if the actual belt movement has occurred by determining the rate of change of the final counter value for the counter associated with each scanner 24, 26, 28, 30. The algorithm stores a delta count value representing a change in the counter value between the two preceding scan lines for each counter. The algorithm compares a stored delta count value with a delta count value indicating a change in the count value between the current scan line and the preceding scan line.

If the delta counter value for a counter associated with a particular scanner 24, 26, 28, 30 indicates that a move has taken place, then the algorithm will check the other three counters in the same way to determine if similar delta count values are being maintained. Inquire. If only one counter maintains the delta count value change, a belt fault has occurred. In this case, the counter is loaded with a preceding composite belt edge value that does not provide any correction for belt movement. However, if all four counters display similar delta counter values, the actual belt movement has occurred. In this case, each counter is loaded with a new composite belt edge value representing the necessary correction for belt movement. Thus, based on the algorithm, the controller 100 identifies the final count value for the belt edge detection signal associated with the engagement, as shown by block 190. If the algorithm indicates that the final count value is the result of a belt edge defect, the controller 100 ignores the final count value. In this case, the controller 100 reloads the counter with the existing synthetic belt edge value as indicated by line 192. If the algorithm indicates that the final count value is not the result of a belt edge defect, the controller 100 determines the amount of correction required by the laser beam as indicated by block 194. The controller 100 adjusts the existing composite belt edge value according to the required correction and reloads the counter of the belt edge synthesizer 102 with the new composite belt edge value as indicated by line 196. To avoid the sudden adjustment seen in the final multicolor image, it may be desirable to set the maximum correction value per scan line.

Belt edge synthesizer 102 provides each new composite belt edge value to scan control and synchronization module 88. In response, the scan control and synchronization module 88 generates an image scan start signal at that time regarding the scan start of each scanner 24, 26, 28, 30. Computer 78 initiates modulation of each laser beam in response to an image scan start signal for the particular laser beam. Based on the composite belt edge value and the pixel clock, the scan control and synchronization module 88 is configured to initiate each image scan segment at a substantially fixed distance relative to the left edge 62 of the photoconductor belt 12. Timely adjusts the image scan start signal for each scanner 24, 26, 28, 30 so that 78 controls the modulation of each laser beam. In this manner, the computer 78 controls the modulation of each laser beam 46, 48, 50, 52 based on the belt edge detection signal generated by the scan line of the specific laser beam.

The belt edge synthesizer 102 also operates in conjunction with the belt steering controller 103 to form part of the belt steering control system according to the present invention. In particular, the belt edge synthesizer 102 is based on the belt edge detection signals received from the belt edge detectors 92, 94, 96, 98, and a composite belt for each scanner and each scan line as indicated by line 139. The edge value signal is transmitted to the belt steering controller 103. The composite belt edge value signal provides the belt steering controller 103 with an indication of the current position of the photoconductor belt 12 for the ideal transport path extending in the direction 44. Based on the composite belt edge value, the belt steering controller 103 controls the belt steering mechanism to move the photoconductor belt 12 in a direction substantially perpendicular to the continuous path of the belt in direction 44. The belt steering controller 103 controls the belt steering mechanism based on the composite belt edge value signal to reduce the deviation of the photoconductor belt 12 from the continuous path. Accordingly, the belt steering controller 103 may include a driver circuit for a drive belt steering mechanism that operates in conjunction with, for example, a control circuit for controlling the driver circuit based on the composite belt edge value signal and processing the composite belt edge value. Can be. When the deviation is reduced by the belt steering mechanism, it provides more accurate polymerization of the image scan segment formed by the laser beams 46, 48, 50, 52 scanned by the scanners 24, 26, 28, 30. Enhance the polymerization of the final latent image on the conductor 12. The reduced deviation also prevents damage to the photoconductor belt 12 and helps to maintain the belt on the transfer roller.

6 and 7 illustrate a typical photoconductor belt device 198 using a belt steering control system useful in a polymerization system, in accordance with the present invention. For convenience of illustration, FIG. 7 shows one of a plurality of scanners 24, 26, 28, 30 placed in order to scan the laser beams 46, 48, 50, 52 across the photoconductor belt 12; Only one of the belt edge detectors 92, 94, 96, 98 is shown. 6 and 7 show that a belt edge detector is installed on the circuit board 199 as the photodetector 120. In the exemplary device of FIGS. 6 and 7, the photoconductor belt 12 is installed around a plurality of rollers 200, 202, 204, 206, 208. The shaft of one of the rollers 200, 202, 204, 206 is connected to a drive mechanism such as a motor (not shown) either directly or through any of several drive transmission devices. The drive mechanism drives the roller, which frictionally drives the photoconductor belt 12 to move around the rollers 200, 203, 204, 206, 208 in the continuous transport path in the direction indicated by the arrow 44. . As shown in Figures 6 and 7, the roller 202 is supported on a pivotable carriage 210 that forms part of the belt steering mechanism according to the present invention. 8A and 8B show the carriage 210 in more detail. The pivotable carriage 210 includes a set of carriage mounts 212, 214. Each carriage mount 212, 214 holds one end of a roller 202 shaft. The carriage 210 is installed in the carriage pin 216 in a fixed manner. The carriage pin 216 is installed at the center of the carriage 210. The carriage 210 moves the photoconductor belt 12 in a direction perpendicular to the transmission path by rotating about a steering axis A-A 'that meets the longitudinal axis of the carriage pin 216. In order to rotate, the carriage pin 210 is installed in a journal bearing (not shown) of the support block 218. The support block 218 includes a support plate 220. The first and second block mounts 222 and 224 are connected to the support plate 220. The first and second block mounts 222, 224 hold opposite ends of the shaft associated with the rollers 200, 204.

In this example, the belt steering mechanism functions as a roller adjustment mechanism that adjusts the position of the roller 202 to move the photoconductor belt 12. The roller adjustment mechanism can be implemented by several different mechanisms. As shown in the examples of FIGS. 6, 7 and 8A, the roller adjustment mechanism includes a solenoid 226 with an actuator 228 connected to an actuator pin 230 extending outward from the carriage pin 216. can do. Many different actuator mechanisms can be used, for example, as a stepper motor. Solenoid 226 is installed on bracket 232 connected to support block 218. The actuator pin 230 extends through a hole 234 in the actuator 228 of the solenoid 226. The actuator extends perpendicular to the carriage pins 216 and consequently also extends perpendicular to the steering axis A-A '. Belt steering controller 103 transmits a signal that selectively activates or deactivates solenoid 226 to move actuator 228 in or out relative to the solenoid. Thus, the actuator 228 moves the actuator pin 230 to rotate the carriage pin 216 within the journal bearing of the support block 210. When the carriage pin 216 rotates, the attitude | position of the roller 202 with respect to the other rollers 200, 204, 206, 208, 210 is adjusted. The photoconductor belt 12 moves in a direction perpendicular to the continuous conveying path in response to the positioning of the roller 202. In particular, the photoconductor belt 12 is moved along the lateral direction of the roller 202 in response to the change in the attitude of the roller.

The belt steering controller 103 is based on the belt edge detection signal generated by the photodetectors 92, 94, 96, 98 and in particular a belt edge synthesizer to reduce the deviation of the photoconductor belt 12 from the continuous conveying path. The belt steering mechanism is controlled based on the composite edge value generated by 102. In this manner, the belt steering controller 103 reduces the significant deviation that the latent image formed by the scanners 24, 26, 28, 30 can cause misalignment on the photoconductor belt 12. The belt steering controller 103 may be configured to activate the solenoid 226 based on the composite edge value for a period of time sufficient for the photoconductor belt 12 to move along the roller 202 to the appropriate side position of the transmission path. have. The time period can be determined based on the positional information provided by the composite edge value and information of the rate of movement characteristic of the photoconductor belt 12 along the roller 202. The belt steering controller 103 may also be configured to activate the solenoid 226 for a period of time until the belt edge detection signal and thus the composite belt edge value indicates that the belt edge position has returned to the proper position.

Alternatively, solenoid 226 may be configured to move actuator 228 between multiple locations in response to different levels of activation or different control signals. In this case, the belt steering controller 103 may be configured to apply a signal to the solenoid 226 that drives the actuator 228 to a specific position based on the composite edge value. This particular position may be selected to achieve angular rotation of the carriage pin 216 sufficient to move the photoconductor belt 12 to its side position. As another variant, the belt steering controller 103 may be configured to adjust both the position and activation time of the solenoid 226 to achieve the desired movement of the photoconductor belt 12.

In the scan control system, the solenoid 226 and the belt steering controller 103 may be configured to provide only the maximum degree of movement of the photoconductor belt 12 at a given time to avoid sudden adjustments that may be seen in the final multicolor image. have. In addition, the belt steering controller 103 may be configured to control the solenoid 226 in response to the composite edge value received for each scan line as in the scan control system. However, in particular when the scan control system of the present invention is used, it may be sufficient to allow the belt steering system to operate on a less frequent basis, such as every n scan lines.

Although exemplary embodiments of the invention have been described, those skilled in the art will readily be able to make additional advantages and modifications in light of the details and examples of the invention disclosed herein. Accordingly, the description and examples are to be understood as illustrative only, in light of the scope and spirit of the invention as set forth in the claims.

Claims (22)

A system for polymerizing a latent image on a photoconductor belt, the system comprising A photoconductor belt installed around the plurality of rollers, A drive mechanism for driving the photoconductor belt, wherein the photoconductor belt tends to deviate from the continuous path in a direction substantially perpendicular to the continuous path to move in a continuous path around the roller; A photodetector disposed to overlap the edge of the photoconductor belt; A scanner for scanning a laser beam across the moving photoconductor belt and across the photodetector, wherein the photodetector generates a belt edge detection signal when the laser beam is scanned across the photodetector; A scan controller for modulating the laser beam based on image data to form a latent image on the photoconductor belt; A belt steering mechanism for moving the photoconductor belt in a direction substantially perpendicular to the continuous path, A belt steering controller for controlling the belt steering mechanism based on the belt edge detection signal to reduce the deviation of the photoconductor belt from the continuous path And a system for polymerizing a latent image on a photoconductor belt. The scanner of claim 1, wherein the laser beam is projected onto the photodetector substantially perpendicular to the photoconductor belt and projected onto an edge of the photoconductor belt substantially perpendicular to the photoconductor belt. And optical means disposed between the photodetector and the latent image on the photoconductor belt. 3. The latent image on the photoconductor belt of claim 2, wherein the optical means comprises a prism disposed between the scanner and the photoconductor belt, the prism overlapping the edge of the photodetector and the photoconductor belt. System for polymerization. The belt steering mechanism of claim 1, wherein the belt steering mechanism includes a roller adjustment mechanism for adjusting the position of one of the rollers, the photoconductor belt being substantially perpendicular to the continuous path in response to the adjustment of the position of each roller. A system for polymerizing a latent image on a photoconductor belt that tends to move. The apparatus of claim 1, wherein the photodetector continues to generate the belt edge detection signal until a laser beam is projected onto the edge of the photoconductor belt, and the belt steering controller is based on the duration of the belt edge detection signal. Means for determining the edge position of the photoconductor belt, wherein a belt steering controller controls the belt steering mechanism based on the determined position. The optical scanner of claim 1, wherein the scanner scans the laser beam across a photoconductor belt of a plurality of scan lines, the scan controller being a first scan controller, wherein the first scan controller is a light having a plurality of image scan segments. Modulating the laser beam based on the image data to form a latent image on a conductor belt, each of the image scan segments forming a portion of one scan line, the system with respect to the edge of the photoconductor belt. And further comprising a second scan controller for controlling modulation of the laser beam based on the belt edge detection signal to start each image scan segment at a substantially fixed distance. System for doing so. A system for polymerizing a plurality of latent images on a photoconductor belt, the system comprising A photoconductor belt installed around the plurality of rollers, A drive mechanism for driving the photoconductor belt, wherein the photoconductor belt tends to deviate from the continuous path in a direction substantially perpendicular to the continuous path to move in a continuous path around the roller; A photodetector disposed to overlap the edge of the photoconductor belt; A first laser beam across the moving photoconductor belt and across the photodetector, wherein the photodetector generates a belt edge detection signal when the first laser beam is scanned across the photodetector. 1 scanner, A second scanner for scanning a second laser beam across the moving photoconductor belt; Modulating the first laser beam based on first image data to form a first latent image on the photoconductor belt, and generating the first latent image on the photoconductor belt and the second image data based on second image data to form a second latent image on the photoconductor belt. A scan controller for modulating 2 laser beams, A belt steering mechanism for moving the photoconductor belt in a direction substantially perpendicular to the continuous path, A belt steering controller for controlling the belt steering mechanism based on the belt edge detection signal to reduce the deviation of the photoconductor belt from the continuous path And a system for polymerizing a plurality of latent images on the photoconductor belt. 8. The method of claim 7, wherein the first laser beam is projected onto the photodetector substantially perpendicular to the photoconductor belt and to be projected onto the edge of the photoconductor belt substantially perpendicular to the photoconductor belt. Further comprising optical means disposed between said first scanner and said photodetector. 9. The photoconductor belt of claim 8, wherein the optical means comprises a prism disposed between the first scanner and the photoconductor belt, wherein the prism overlaps the edge of the photodetector and the photoconductor belt. A system for polymerizing a plurality of latent images. 8. The belt steering mechanism of claim 7, wherein the belt steering mechanism includes a roller adjustment mechanism for adjusting the position of one of the rollers, the photoconductor belt being substantially perpendicular to the continuous path in response to the adjustment of the position of each roller. A system for polymerizing a plurality of latent images on a photoconductor belt that tends to move. 8. The apparatus of claim 7, wherein the photodetector continues to generate the belt edge detection signal until a laser beam is projected onto the edge of the photoconductor belt, wherein the belt steering controller is based on the duration of the belt edge detection signal. Means for determining the position of the edge of the photoconductor belt, wherein a belt steering controller controls the belt steering mechanism based on the determined position. . The method of claim 7, wherein the first scanner scans the first laser beam across the photoconductor belts of the plurality of first scan lines, and the second scanner traverses the photoconductor belts of the plurality of second scan lines. And scan the second laser beam, wherein the scan controller is a first scan controller, wherein the first scan controller is coupled to the first image data to form a first latent image on a photoconductor belt having a plurality of image scan segments. Modulating the first laser beam based on each of the first image scan segments forming a portion of one first scan line, the first scan controller having a plurality of second image scan segments. Modulating the second laser beam based on the second image data to form a second latent image on a belt, each second image scan segment being one Forming a portion of a second scan line, the system configured to initiate the first image scan segment at a substantially fixed distance with respect to the edge of the photoconductor belt based on the belt edge detection signal. A second scan controller for controlling modulation of the second laser beam based on the belt edge detection signal to control modulation and to start each second image scan segment at a substantially fixed distance to the edge of the photoconductor belt Further comprising a system for polymerizing a plurality of latent images on the photoconductor belt. 8. The apparatus of claim 7, wherein a third scanner for scanning a third laser beam across a moving photoconductor belt, wherein a scan controller is based on third image data to form a third latent image on the photoconductor belt. Modulating a third laser beam; and a fourth scanner for scanning a fourth laser beam across the moving photoconductor belt, wherein a scan controller is configured to form a fourth image to form a fourth latent image on the photoconductor belt. And modulating a fourth laser beam based on the data. The method of claim 13, wherein the first scanner scans the first laser beam across the photoconductor belts of the plurality of first scan lines, and the second scanner traverses the photoconductor belts of the plurality of second scan lines. Scan the second laser beam, the third scanner scans the third laser beam across the photoconductor belt of the plurality of third scan lines, and the fourth scanner transmits the light of the plurality of fourth scan lines. Scan the fourth laser beam across a conductor belt, the scan controller being a first scan controller, wherein the first scan controller is configured to form a first latent image on a photoconductor belt having a plurality of image scan segments; Modulating the first laser beam based on one image data, wherein each of the first image scan segments forms a part of one first scan line, and the first scan agent The modulator modulates the second laser beam based on the second image data to form a second latent image on the photoconductor belt having a plurality of second image scan segments, each second image scan segment being one Forming a portion of a second scan line, wherein the first scan controller is configured to form a third latent image on the photoconductor belt having a plurality of third image scan segments based on the third image data. Each third image scan segment forms a portion of one second scan line, and the first scan controller is configured to form a fourth latent image on the photoconductor belt having a plurality of fourth image scan segments. Modulating the fourth laser beam based on the fourth image data, wherein each of the fourth image scan segments is part of one fourth scan line. The system controls the modulation of the first laser beam based on the belt edge detection signal to start each first image scan segment at a substantially fixed distance relative to the edge of the photoconductor belt, Control modulation of the second laser beam based on the belt edge detection signal to start each second image scan segment at a substantially fixed distance with respect to the edge of the photoconductor belt and substantially with respect to the edge of the photoconductor belt. Control the modulation of the third laser beam based on the belt edge detection signal to start each third image scan segment at a fixed distance, wherein each fourth at a substantially fixed distance to the edge of the photoconductor belt. Based on the belt edge detection signal to start an image scan segment. And a second scan controller for controlling the modulation of the fourth laser beam. A system for polymerizing a plurality of latent images on a photoconductor belt, the system comprising A photoconductor belt installed around the plurality of rollers, A drive mechanism for driving the photoconductor belt, wherein the photoconductor belt shifts away from the continuous path in a direction substantially perpendicular to the continuous path to move in a continuous path around the roller; A first photodetector disposed to overlap the edge of the photoconductor belt; A second photodetector disposed to overlap the edge of the photoconductor belt; A first laser beam across the moving photoconductor belt and across the first photodetector, wherein the first photodetector sends a first belt edge detection signal when the first laser beam is scanned across the first photodetector. Create—a first scanner for scanning; A second laser beam across the moving photoconductor belt and across the second photodetector, wherein the second photodetector sends a second belt edge detection signal as the second laser beam is scanned across the second photodetector; Creates a second scanner for scanning; Modulating the first laser beam based on first image data to form a first latent image on the photoconductor belt, and generating the first latent image on the photoconductor belt and the second image data based on second image data to form a second latent image on the photoconductor belt. A scan controller for modulating 2 laser beams, A belt steering mechanism for moving the photoconductor belt in a direction substantially perpendicular to the continuous path, A belt steering controller for controlling the belt steering mechanism based on the belt edge detection signal to reduce the deviation of the photoconductor belt from the continuous path And a system for polymerizing a plurality of latent images on the photoconductor belt. 16. The method of claim 15, wherein the first laser beam is projected onto the photodetector substantially perpendicular to the photoconductor belt and to be projected onto the edge of the photoconductor belt substantially perpendicular to the photoconductor belt. First optical means disposed between the first scanner and the first photodetector, and the second laser beam is projected onto the photodetector substantially perpendicular to the photoconductor belt and substantially on the photoconductor belt Polymerizing a plurality of latent images on the photoconductor belt, further comprising second optical means disposed between the second scanner and the second photodetector to be projected onto the side of the photoconductor belt vertically. System. 17. The apparatus of claim 16, wherein the first optical means is disposed between the first scanner and the photoconductor belt, wherein the first prism overlaps the edge of the first photodetector and the photoconductor belt. A plurality of latent images on the photoconductor belt, the second prism disposed between the second scanner and the photoconductor belt, wherein the second prism overlaps the edge of the second photodetector and the photoconductor belt. System for polymerizing. 16. The belt steering mechanism of claim 15, wherein the belt steering mechanism includes a roller adjustment mechanism for adjusting the position of one of the rollers, the photoconductor belt being substantially perpendicular to the continuous path in response to the adjustment of the position of each roller. A system for polymerizing a plurality of latent images on a photoconductor belt that tends to move. 16. The apparatus of claim 15, wherein the first photodetector continues to generate the first belt edge detection signal until the first laser beam projects on the edge of the photoconductor belt, wherein the second photodetector The second belt edge detection signal is continuously generated until two laser beams project onto the edge of the photoconductor belt, and the belt steering controller detects the duration of the first belt edge detection signal and the second belt edge detection. Means for determining the edge position of the photoconductor belt based on the duration of the signal, wherein a belt steering controller controls the belt steering mechanism based on the determined position. System for polymerizing a latent image. The method of claim 15, wherein the first scanner scans the first laser beam across the photoconductor belts of the plurality of first scan lines, and the second scanner traverses the photoconductor belts of the plurality of second scan lines. And scan the second laser beam, wherein the scan controller is a first scan controller, wherein the first scan controller is coupled to the first image data to form a first latent image on a photoconductor belt having a plurality of image scan segments. Modulating the first laser beam based on each of the first image scan segments forming a portion of one first scan line, wherein the first scan controller is on a photoconductor belt having a plurality of second image scan segments. Modulating the second laser beam based on the second image data to form a second latent image in each second image scan segment, one second Forming a portion of a scan line, the system configured to start the first image scan segment at a substantially fixed distance with respect to the edge of the photoconductor belt, wherein the first edge of the laser beam is detected based on the belt edge detection signal. A second scan for controlling modulation and controlling modulation of the second laser beam based on the belt edge detection signal to start each second image scan segment at a substantially fixed distance to the edge of the photoconductor belt And a controller, the system for polymerizing a plurality of latent images on the photoconductor belt. 16. The apparatus of claim 15, further comprising: a third scanner for scanning a third laser beam across the moving photoconductor belt, wherein the scan controller is configured to generate a third latent image on the photoconductor belt based on the third image data. 3 modulating the laser beam—and a fourth scanner for scanning the fourth laser beam across the moving photoconductor belt, wherein the scan controller is based on the fourth image data to form a fourth latent image on the photoconductor belt. And modulating the fourth laser beam—the system for polymerizing the plurality of latent images on the photoconductor belt. The method of claim 21, wherein the first scanner scans the first laser beam across the photoconductor belts of the plurality of first scan lines, and the second scanner traverses the photoconductor belts of the plurality of second scan lines. Scan the second laser beam, the third scanner scans the third laser beam across the photoconductor belt of the plurality of third scan lines, and the fourth scanner transmits the light of the plurality of fourth scan lines. Scan the fourth laser beam across a conductor belt, the scan controller being a first scan controller, wherein the first scan controller is configured to form a first latent image on a photoconductor belt having a plurality of image scan segments; Modulating the first laser beam based on one image data, wherein each of the first image scan segments forms a part of one first scan line, and the first scan agent The modulator modulates the second laser beam based on the second image data to form a second latent image on the photoconductor belt having a plurality of second image scan segments, each second image scan segment being one Forming a portion of a second scan line, wherein the first scan controller is configured to form a third latent image on the photoconductor belt having a plurality of third image scan segments based on the third image data. Each third image scan segment forms a portion of one second scan line, and the first scan controller is configured to form a fourth latent image on the photoconductor belt having a plurality of fourth image scan segments. Modulating the fourth laser beam based on the fourth image data, wherein each of the fourth image scan segments is part of one fourth scan line. And the system is configured to determine the first laser beam based on the first and second belt edge detection signals to start each first image scan segment at a substantially fixed distance relative to the edge of the photoconductor belt. Control modulation of the second laser beam based on the first and second belt edge detection signals to control modulation and to start each second image scan segment at a substantially fixed distance to the edge of the photoconductor belt. And control modulation of the third laser beam based on the first and second belt edge detection signals to start each third image scan segment at a substantially fixed distance relative to the edge of the photoconductor belt. The first and the first and second scan segments to start each fourth image scan segment at a substantially fixed distance to the edge of the conductor belt. And a second scan controller for controlling the modulation of said fourth laser beam based on a second belt edge detection signal.