CN1749020A - Be used for the method and apparatus that correcting imaging equipment drawing picture is aimed at - Google Patents

Abstract

A method and apparatus for correcting image registration of an imaging device that uses a thermal printhead to apply heat to a first side and a second side of media to print an image. In the method and device, after the first pattern is printed on the first pre-printing area on the first side of the medium, the sensor detects the first actual printing area on the first side of the medium; After the second pattern is printed on the second pre-print area, the sensor detects the first-second actual print area on the second side of the medium; using the first pre-print area, the second pre-print area, the detected The first actual printing area, and the detected first-second actual printing area calculate the position offset between the actual printing areas of the first and second sides; then use the calculated position offset to The pre-print areas on the first and second sides of the media are corrected.

Description

Method and apparatus for correcting image alignment of an imaging device

technical field

The present invention relates to an image forming apparatus using a thermal print head. More specifically, the present invention relates to a method and apparatus for correcting image registration of an imaging device that uses a thermal printhead to apply heat to a first side and a second side of media to print an image.

Background technique

Thermal printers use a thermal printhead to apply heat to an ink ribbon that contacts the media to transfer ink from the ribbon to the media, or directly to media coated with ink that develops colors when heated.

FIG. 1 is a view of a prior art thermosensitive medium.

Referring to FIG. 1 , the thermosensitive medium includes a substrate 11 , a first side 10 a , a second side 10 b and a reflective layer 13 . Ink layers of different colors are formed on the first side 10a and the second side 10b. For example, yellow and magenta layers may be sequentially formed on the first side 10a, and a cyan layer may be formed on the second side 10b. The substrate 11 may consist of a transparent material. The reflective layer 13 reflects light so that a color image can be observed from the first side 10a.

FIG. 2 is a schematic diagram showing the configuration of an image forming apparatus using a thermal print head according to the prior art.

Referring to FIG. 2 , the image forming apparatus includes a medium 200 , a driving roller 210 , a driven roller 220 , a pressing roller 230 and a thermal print head 240 .

A motor (not shown) rotates the driving roller 210 to convey the medium 200 interposed between the driving roller 210 and the driven roller 220 .

The thermal head 240 applies heat to the medium 200 being conveyed to print yellow, magenta, and cyan data. The pressing roller 230 faces the thermal head 240 with the medium 200 interposed therebetween. The platen roller 230 rotates as the medium is conveyed, and supports the medium 200 receiving heat from the thermal head 240 for color printing.

In order to print yellow, magenta, and cyan data with one thermal printhead 240, the thermal printhead 240 must apply heat to the first and second sides 10a, 10b of the media 200.

As mentioned above, if a thermal printhead is used to apply heat to the first and second sides of the media, a mechanical offset or media path difference occurs such that the actual print areas on the first and second sides of the media do not align with each other If the color is not correct, the resulting printed image will not have the exact desired color.

Therefore, when a thermal print head is used, it is necessary to align the sides of the print medium so that the printed image is accurately colored.

Contents of the invention

The present invention provides a method and apparatus for correcting the image registration of an imaging device, wherein the media's first print area is calculated by comparing the pre-printed area of the pattern on the first and second sides with the actual printed area detected by a sensor. The position offset of the actual printing area on the first and second sides, and use the calculated position offset to correct the pre-printing area, so that the actual printing of the first side and the second side can be accurately and conveniently Alignment between regions is corrected.

According to one aspect of the present invention, there is provided a method of correcting image registration of an imaging device configured with a thermal printhead for printing by applying heat to first and second sides of media, the method comprising: After printing the first pattern on the first preliminary printing area on the first side of the medium, using a sensor to detect the first actual printing area on the first side of the medium; after printing the second pattern on the second preliminary printing area on the second side of the medium, Using a sensor to detect a first-second actual print area of the medium; using the first pre-print area, the second pre-print area, the detected first actual print area, and the detected first-second actual print area, calculating a position offset between the actual printing areas of the first and second sides; and correcting the printing position of the first or second side of the medium by using the calculated position offset.

The steps of each of the detecting operations may include: receiving image data of the medium from the detector; determining a change in the image data; and detecting an actual print area using the determined change in the image data.

The change in the image data may be a rising edge or a falling edge of the image data.

The correction of the printing position may be performed by correcting a first heating initiation point at which the thermal printhead begins to apply heat to the first side of the media or a second heating initiation point at which the thermal printhead begins to apply heat to the second side of the media.

According to another aspect of the present invention, a method of correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing is provided. The method includes: after printing the first pattern on the first pre-print area on the first side of the medium, using a sensor to detect the first actual print area on the first side of the medium; printing on the second pre-print area on the second side of the medium After the second pattern, use the sensor to detect the first-second actual printing area of the medium, the second pre-printing area overlaps the first pre-printing area on the first side of the media; using the first pre-printing area area, the second preliminary printing area, the detected first actual printing area and the detected first-second actual printing area, calculate the position offset between the actual printing area of the first and second sides; and use The calculated position offset, which corrects the print position for the first or second side of the media.

The thermal printhead is rotatable to face the first side and the second side of the media.

Each of the patterns may have a polygonal shape.

The steps of each detection operation include: receiving media image data from the detector; determining a change in the image data; and detecting an actual print area using the determined change in the image data. The change in the image data may be a rising edge or a falling edge of the image data.

The step of calculating the position offset may include: calculating a difference between the center of the first pre-printing area and the center of the second pre-printing area; calculating the difference between the detected center of the first actual printing area and The actual printing area difference between the detected first-second actual printing area centers; using the calculated preparatory area difference and the actual printing area difference, calculate the position offset; calculate the first edge-area The edge-area distance difference between the edge-area distance and the second edge-area distance, wherein the first edge-area distance is the distance from the edge of the media to the first actual print area, and the second edge-area distance is the distance from the edge of the medium to the first-second actual printing area, the edge and the actual printing area are detected in the above detection operation; and using the edge-area distance difference to correct the position offset .

The step of correcting the printing position may be performed by correcting a first heating initiation point at which the thermal printhead begins to apply heat to the first side of the medium or a second heating initiation point at which the thermal printhead begins to apply heat to the second side of the medium.

According to another aspect of the present invention, there is provided an apparatus for correcting image registration of an image forming apparatus configured with a thermal printhead that applies heat to first and second sides of media for printing. The device includes: a pattern printer for printing a first pattern on a first pre-print area on the first side of the medium and printing a second pattern on a second pre-print area on the second side of the medium; an area detector for detecting the actual print area of the media; an offset calculator for comparing said pre-print area with the actual print area detected by the area detector to calculate the difference between the actual print area of the first and second sides of the media a positional offset; and a correction means for correcting the printing position of the first or second side of the medium using the calculated positional offset.

The pattern printer may include: a conveyor for conveying the medium; a thermal head for applying heat to the first and second sides of the medium to perform a printing operation; a print controller for controlling the conveyor and the thermal printing The head is configured to print a first pattern on a first pre-print area on a first side of the media and a second pattern on a second pre-print area on a second side of the media. The pattern printer may also include a head positioner for rotating the thermal head so that the thermal head faces the first and second sides of the media. Each of the patterns may have a polygonal shape.

The area detector may include a sensor for detecting images from the medium and outputting corresponding image data, and a distance detector for determining changes in the image data to detect distances between the changes.

The distance detector may determine changes in the image data and detect distances between the changes by using an encoder.

The change in the image data may be a rising edge or a falling edge of the image data.

The offset calculator may include: a memory for storing the detected pre-printing area of the actual printing area; a storage controller for controlling the memory to store the first pre-printing area, the second pre-printing area , the first actual printing area detected by the area detector after the first pattern is printed on the medium, and the first actual printing area detected by the area detector after the first and second patterns are printed on the medium One - the second actual printing area; a difference calculator, used to calculate the difference between the center of the first pre-printing area and the center of the second pre-printing area, and calculate the detected first an actual print area difference between the center of the actual print area and the detected first-second actual print area centers; and an offset output unit for utilizing the calculated preparatory area difference and the actual print area difference , to calculate the offset of the position.

The offset calculator may further include: a compensation value calculator for calculating an edge-area distance difference between a first edge-area distance and a second edge-area distance, wherein the first edge-area distance is The distance from the edge of the medium to the first actual print area, and the second edge-area distance is the distance from the edge of the medium to the first-second actual print area; Correct the position offset calculated by the offset output unit based on the calculated edge-area distance difference.

The correcting device can use the calculated positional offset to correct the first heating start point when the thermal print head starts to apply heat to the first side of the medium, or the first heating start point when the thermal print head starts to apply heat to the second side of the medium. Second, the starting point of heating is corrected.

According to yet another aspect of the present invention, there is provided a method of correcting image registration of an imaging device, wherein a thermal printhead applies heat to a first side of the media after the media is loaded along a first transport path, and when the media is loaded along a first transport path The thermal head applies heat to the second side of the media after a second delivery channel is loaded with the media. The method includes: when the medium is loaded along the first conveying path, detecting the medium by a sensor and storing a first analog signal output by the sensor in the recording medium; when loading the medium along the second conveying path , the medium is detected by the sensor and the second analog signal output by the sensor is stored in the recording medium; using the first and second analog signals stored in the recording medium, the first and second sides of the medium are calculated a positional offset between the actual printing areas; and using the calculated positional offset to correct the printing position of the first or second side of the medium.

The thermal printhead is rotatable to face the first and second sides of the media. The respective first and second analog signals may be output by detecting a predetermined portion of the medium, including an edge of the medium.

The step of calculating the position offset may include: calculating an output ratio of the first analog signal to the second analog signal; and calculating the position offset using the calculated output ratio.

Calculating the position offset by the calculated output ratio may include: calculating an imaginary reference value by multiplying the calculated output ratio by a digital reference value of the sensor; the position of the imaginary reference value; and calculating a position offset between the detected position and the position having the digital reference value in the stored second analog signal.

Calculating the position offset by the calculated output ratio may include: obtaining an imaginary reference value by multiplying the calculated output ratio by a digital reference value of the sensor; the position of the imaginary reference value; and calculating a position offset between the detected position and the position having the digital reference value in the stored first analog signal.

The step of correcting the printing position may be performed by correcting a first heating initiation point at which the thermal printhead begins to apply heat to the first side of the medium or a second heating initiation point at which the thermal printhead begins to apply heat to the second side of the medium.

According to yet another aspect of the present invention, a method of correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing is provided. The method includes: respectively printing first and second patterns on first and second pre-printing areas on the first side of the medium; after printing the third pattern on the third pre-printing area on the second side of the medium, detecting the The actual printing areas of the first to third patterns; using the detected actual printing areas, calculate the offset between the actual printing positions of the first and second sides; Or the printing position of the second side to correct.

The first, second and third pre-printing areas may be spaced apart from each other by the same distance.

The detecting of the actual printing area may include: receiving medium image data from the sensor; detecting a change in the image data; and detecting the actual printing area of the medium through the detected change in the image data.

The change in the image data may be a rising edge or a falling edge of the image data.

The step of calculating the position offset may include: calculating a first-second distance value between the detected centers of the first and second patterns; calculating a first-second distance value between the detected centers of the second and third patterns. second-third distance value; and calculating a center distance difference between the first-second difference and the second-third difference.

According to still another aspect of the present invention, there is provided a computer-readable recording medium having a computer-readable program for executing the above-mentioned alignment correction method.

According to yet another aspect of the present invention, there is provided an apparatus for correcting image alignment of an imaging device, wherein the thermal printhead applies heat to a first side of the media after the media is loaded along a first transport path, and when the media is loaded along a first transport path The thermal head applies heat to the second side of the media after a second transport channel is loaded with the media to perform printing on the first and second sides of the media. The device comprises: conveying means for conveying the medium; an analog signal generator for detecting the medium to generate corresponding first and second analog signals when the medium is conveyed along said first and second conveying channels; an offset calculator, which uses said first and second analog signals to calculate an offset between the actual print areas of the first and second sides of the medium; The printing position of one or the second side is corrected.

The thermal printhead is rotatable to face the first and second sides of the media. The respective first and second analog signals may be output by detecting a predetermined portion of the medium, including an edge of the medium.

The analog signal generator may include: a sensor for detecting the medium as it is transported along the first and second transport paths to generate corresponding first and second analog signals; a recording medium for storing the said first and second analog signals; and a controller for controlling storage of said first and second analog signals in a recording medium.

The offset calculator may include: a ratio calculator for calculating an output ratio of the first analog signal to the second analog signal; and a distance calculator for calculating a position offset by the calculated output ratio .

The distance calculator may include: a reference calculator for calculating an imaginary reference value by multiplying the calculated output ratio by a digital reference value of the sensor; a position in the analog signal having the virtual reference value; and a position distance calculator that calculates a position offset using the detected position and the position having the digital reference value in the stored second analog signal.

The distance calculator may include: a reference calculator for calculating an imaginary reference value by multiplying the calculated output ratio by a digital reference value of the sensor; a position in the analog signal having the virtual reference value; and a position distance calculator for calculating a position offset using the detected position and the position having the digital reference value in the stored first analog signal.

According to yet another aspect of the present invention, there is provided an apparatus for correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing. The apparatus includes: a pattern printer for printing first and second patterns on a first side of the media and a third pattern on a second side of the media; an area detector for detecting the actual printed area of the media; an offset calculator for Comparing the actual printing area detected by the area detector to calculate an offset between the actual printing positions of the first and second sides of the medium; Or the printing position of the second side to correct.

The first, second and third patterns may be spaced apart from each other by the same distance. The pattern printer may include: a conveying device for conveying a medium; a thermal head applying heat to first and second sides of the medium to perform a printing operation; and a printing controller for controlling the conveying device and the thermal head , to print the first and second patterns on the first and second pre-printing areas on the first side of the medium, and print the third pattern on the third pre-printing area on the second side of the medium.

The alignment correction device may further include a head position adjuster for rotating the thermal head such that the thermal head faces the first and second sides of the media.

The area detector may include: a sensor for detecting images from the medium and outputting corresponding image data; and a distance detector for determining changes in the image data to detect distances between the changes. The change in the image data may be a rising edge or a falling edge of the image data.

The offset calculator may include: a memory for storing the detected actual printing area; a controller for, after the first, second and third patterns are printed on the medium, set the area detector to The detected actual printing area is stored in the recording medium; the difference calculator is used to calculate the first-second distance value between the centers of the detected first and second patterns and the detected second and second patterns. a second-third distance value between centers of the third pattern; and an offset output unit configured to output a difference between the first-second distance value and the second-third distance value.

According to still another aspect of the present invention, there is provided a computer-readable recording medium having a computer-readable program for executing the above-mentioned alignment correction method.

Description of drawings

The above-mentioned and other features and advantages of the present invention will become more apparent by describing in detail its exemplary embodiments with reference to the accompanying drawings, in which:

Fig. 1 is the view of the thermosensitive medium of prior art;

2 is a schematic diagram showing the construction of an image forming apparatus using a conventional thermal print head according to the prior art;

3 is a schematic diagram showing the construction of an image forming apparatus using a thermal print head according to an embodiment of the present invention;

4 is a block diagram showing the configuration of an alignment correction device according to an embodiment of the present invention;

Figure 5 is a detailed block diagram showing an embodiment of the pattern printer shown in Figure 4;

Figure 6 is a block diagram showing an embodiment of the area detector shown in Figure 4;

7A, 7B and 7C are views showing an embodiment of a method of detecting the actual printed area by using a sensor after the pattern is printed on the first side of the medium;

8A, 8B and 8C are views showing an embodiment of a method for detecting the actual printing area by a sensor after the first and second patterns are printed on the first and second sides of the medium respectively;

Figure 9 is a detailed block diagram showing an embodiment of the offset calculator shown in Figure 4;

10 is a view showing an embodiment of a method of calculating a positional offset between actual print areas of first and second sides of a medium;

FIG. 11 is a flowchart showing a method of correcting image alignment according to one embodiment of the present invention;

Fig. 12 is a flowchart showing an embodiment of the pattern printing operation shown in Fig. 11;

Fig. 13 is a flowchart showing an embodiment of the detection operation of the actual printing area shown in Fig. 11;

FIG. 14 is a specific flowchart showing an embodiment of the positional offset calculation operation shown in FIG. 11;

15 is a block diagram showing the configuration of an alignment correction device according to another embodiment of the present invention;

Fig. 16 is a detailed block diagram showing an embodiment of the pattern printer shown in Fig. 15 according to another embodiment of the present invention;

FIG. 17 is a detailed block diagram showing an embodiment of the area detector shown in FIG. 15;

18A and 18B are views showing an embodiment of a method of printing a pattern on a first side of a medium;

19A and 19B are views showing an embodiment of a method of printing a pattern on a second side of a medium;

Figure 20 is a detailed block diagram showing an embodiment of the offset calculator shown in Figure 15;

21A to 21D are views showing an embodiment of a method of calculating a positional offset between actual print areas of first and second sides of a medium;

FIG. 22 is a flowchart showing a method of correcting image alignment according to another embodiment of the present invention;

Fig. 23 is a specific flowchart showing an embodiment of the pattern printing operation shown in Fig. 22;

Fig. 24 is a flowchart showing an embodiment of the detection operation of the actual printing area shown in Fig. 22;

Fig. 25 is a flowchart showing an embodiment of the calculation operation of the position offset shown in Fig. 22;

26 is a block diagram showing the configuration of an alignment correction device according to another embodiment of the present invention;

Figure 27 is a block diagram showing an embodiment of the analog signal generator shown in Figure 26;

28A to 28D are views showing an embodiment of a method of detecting a medium using a sensor when the medium is transported along the first transport path;

29A to 29D are views showing an embodiment of a method of detecting a medium using a sensor when the medium is transported along the second transport path;

Figure 30 is a block diagram showing an embodiment of the offset calculator shown in Figure 26;

Figure 31 is a graph showing the output signal of the sensor when the edge of the media is detected according to one embodiment of the present invention;

Figure 32 is a block diagram showing an embodiment of the distance calculator shown in Figure 30;

FIG. 33 is a graph showing a method for calculating positional offsets using analog signals from sensors according to one embodiment of the present invention;

34 is a flowchart showing a method of correcting image alignment according to another embodiment of the present invention;

Figure 35 is a flowchart showing an embodiment of the calculation operation of the position offset shown in Figure 34; and

FIG. 36 is a flowchart showing an example of the calculation operation of the positional offset shown in FIG. 34 using the output ratio.

Throughout the drawings, like reference numbers indicate like or similar elements, features, and structures.

Detailed ways

The invention will now be described in more detail with reference to the accompanying drawings.

FIG. 3 is a schematic diagram showing the configuration of an image forming apparatus using a thermal print head according to an embodiment of the present invention.

Referring to FIG. 3, the image forming apparatus includes a pressure roller 305, a thermal print head 310, a driving roller 335, a driven roller 340, an edge detection sensor 345, a medium guide 350, an output driven roller 365, an output roller 370, a pickup roller 380, and Media cassette 390 .

This image forming apparatus using one thermal print head 310 includes at least three conveying channels: first, second and third conveying channels for conveying the medium 320 . Pick rollers 380 pick up the media 320 from the media cassette 390 and provide the media 320 to the first transport path.

Along the second conveying path, the media 320 is conveyed backward or reversed (direction B) for printing, and forwardly along the printing direction (direction F). When the medium 320 is transported along the printing direction (direction F), the thermal print head 310 applies heat to the medium 320 to print.

Along the third transport lane, the media 320 is transported in a rearward direction (direction B) back to the second transport lane for printing on the second side of the media after printing on the first side of the media with the thermal print head 310 . In addition, along the third conveying path, the medium 320 is output in the same direction as the printing direction (direction F) after the printing of the first and second sides is completed.

A media guide 350 may be provided between the first and second delivery channels, directing the media 320 from the first delivery channel to the second delivery channel and directing the media from the second delivery channel to the third delivery channel.

In the second delivery channel, the printing unit 300 prints an image on the medium 320 . Although such an image printing operation of printing once on each side of the medium 320 is performed twice in the present embodiment, the image printing operation may be performed more than twice.

Before an image can be printed on the first or second side of the media 320, the position of the thermal print head 310 must be determined. For example, the thermal print head 310 is in position D when printing a pattern on a first side of the media 320 and in position C when printing another pattern on a second side of the media 320 . The thermal print head 310 and the pressure roller 305 may rotate around the rotation center of the pressure roller 305 to shift the position of the thermal print head 310 . During the displacement of the thermal print head 310 , there should be no contact between the thermal print head 310 and the media 320 . For example, the above-mentioned position shift may occur before the medium 320 is conveyed from the first conveying channel, or before the medium 320 is returned from the third conveying channel to the second conveying channel.

When the medium 320 having finished printing on its first side is conveyed from the third conveying path to the second conveying path along the backward direction (direction B), the thermal print head 310 whose position has been shifted prints an image on the surface of the medium 320. on the second side. During the image printing operation, the conveying device 330 gradually conveys the medium 320 along the printing direction (direction F), and then conveys the medium 320 to the discharge part 360 after completing the image printing operation on the second side of the medium 320 .

When the conveying device 330 conveys the medium 320 , the edge detection sensor 345 detects the edge of the medium 320 . Edge detection sensor 345 may be an optical sensor.

FIG. 4 is a block diagram showing the configuration of an alignment correction apparatus according to an embodiment of the present invention, and FIG. 11 is a flowchart showing an embodiment of an image alignment correction method.

Referring to FIGS. 4 and 11 , the alignment correction device includes a pattern printer 400 , a medium 410 , an area detector 420 , an offset calculator 430 and a correction device 440 . The operation of such an alignment correction device will now be described with reference to FIG. 11 .

In operation 1100 , the pattern printer 400 prints a first pattern on a first pre-print area of a first side of the medium 410 . In operation 1110, the area detector 420 detects an actual printing area (first actual printing area) of the first pattern of the medium through a sensor.

In operation 1120 , the pattern printer 400 prints a second pattern on a second pre-print area on the second side of the medium 410 . In operation 1130 , the area detector 420 detects actual printing areas (first to second actual printing areas) of the first and second patterns on the medium 410 . The above-mentioned first and second pre-printing areas may be rectangular and have portions overlapped with each other, so that the shift in position can be checked with the naked eye.

The offset calculator 430 calculates positional offsets of the first and second patterns by comparing the actual printing area detected in operations 1110 and 1130 with the preliminary printing area.

In operation 1150 , the correction device 440 corrects the first and second pre-printing areas of the first and second sides of the medium 410 according to the above-mentioned calculated positional offset. For example, if the actual printed first pattern exceeds the actual printed second pattern by 0.1 mm, then the print start point on the first side of the medium 410 is corrected backward by 0.1 mm, or the print start point on the second side of the medium 410 Forward correction 0.1mm.

Fig. 5 is a detailed block diagram showing an embodiment of the pattern printer shown in Fig. 4; Fig. 12 is a flowchart showing an embodiment of a method for printing patterns on a medium according to an embodiment of the present invention.

Referring to FIGS. 5 and 12 , the pattern printer 400 includes a printing controller 500 , a conveying device 510 and a thermal print head 520 . The operation of the pattern printer 400 will now be described with reference to FIG. 12 .

In operation 1200, the printing controller 500 controls the conveying device 510 to convey the medium 410 in a backward direction along the printing direction until the medium 410 reaches a preset printing start point. In order to convey the medium 410 to a starting point using the conveying device 510, a sensor may be used to detect the edge of the medium 410 when the medium 410 reaches the starting point.

In operation 1210, the printing controller 500 controls the conveying device 510 to convey the medium 410 by a predetermined length L from the printing starting point in the above-mentioned printing direction. When the medium 410 is conveyed by the length L, the thermal head 520 starts applying heat to the conveyed medium 410 to print a pattern thereon (operation 1220 ).

FIG. 6 is a block diagram showing an embodiment of the area detector shown in FIG. 4, and FIG. 13 is a flow chart showing an embodiment of the detection operation of the actual printing area shown in FIG. 11. Referring to FIG.

Referring to FIGS. 6 and 13 , the area detector 420 includes a sensor 600 and a distance detector 610 . The operation of the area detector 420 will now be described with reference to FIG. 13 .

In operation 1300, when the medium 410 is conveyed to the sensor 600 by the conveying device 510, the sensor 600 detects an actual printing pattern on the medium 410 and converts it into image data.

In operation 1310, the distance detector 610 receives image data from the sensor 600 and detects a change in the image data. The distance detector 610 can detect rising and falling edges of image data.

In operation 1320, the distance detector 610 detects the position of the actual printing area on the medium 410 by calculating the distance between changes of the image data. An encoder (not shown) may be mounted on the drive roller 335, driven roller 340, or pressure roller 305 to generate an electrical signal in response to the rotation of the roller, and the distance detector 610 may use the electrical signal to calculate The moving distance of the medium 410 between changes.

7A, 7B and 7C are views of an embodiment of a method of detecting the actual printed area by using a sensor after printing a pattern on the first side of the media. 7A is a schematic view of the printer configuration, FIG. 7B is a view of an embodiment of a first actual print area on the first side of the media, and FIG. 7C is an image obtained by detecting a pattern printed on the first actual print area of the media view of the data.

Referring to FIG. 7A , the conveying device 510 includes a pressure roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . The conveying device 510 conveys the medium 410 to the printing starting point 720 until the edge detection sensor 700 detects the edge of the medium 410, and then, while the conveying device 510 conveys the medium 410 from the printing starting point 720 along the printing direction, the first pattern is printed on medium 410 . After the first side of the medium 410 is printed, the sensor 600 detects the first actual printing area of the first pattern.

7B, the length a1 represents the distance between the above-mentioned printing start point 720 and the edge of the medium 410, the length a2 represents the first edge-area distance between the edge and the first preliminary printing area, and the length a3 represents the first preliminary printing area. The length of the print area. The first preparation area is rectangular.

7C, the distance detector 610 receives the image data from the sensor 600 and detects the rising and falling edges of the image data, so as to calculate the length b1 between the printing starting point 720 and the edge of the medium 410, the edge and the first The first edge-area distance b2 between the first actual printed areas of the pattern, and the length b3 of the first actual printed areas. The above-mentioned lengths b1, b2, and b3 may also be calculated using the output signal of the encoder 710 installed on the driven roller 335.

Here, the lengths a1, a2, and a3 are used to indicate the pre-printing area, and b1, b2, and b3 are used to indicate the actual printing area.

8A, 8B and 8C are views of an embodiment of a method for detecting the actual printing area by a sensor after printing a first pattern and a second pattern on the first side and the second side of the medium respectively. Fig. 8A is a schematic view showing the structure of the printer, Fig. 8B shows an embodiment view of the first-second actual printing area of the first and second patterns, and Fig. 8C shows the first-second actual printing area by probing Two views of the image data obtained by actually printing the first and second patterns on the area.

Referring to FIG. 8A , the conveying device 510 includes a pressure roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . After printing the first pattern on the first side of the medium, the conveying device 510 conveys the medium 410 to the printing starting point 720 again. From this starting point 720 , the transport device 510 transports the medium 410 again along the printing direction in order to print a second pattern on the second side of the medium 410 . After the second pattern is printed on the second side of the medium 410, the sensor 600 detects the first-second actual printing area of the first pattern and the second pattern.

Referring to Figure 8B, the first-second actual print area of the first and second patterns has a length c3 and is spaced from the edge of the media 410 by an edge-area length c2.

8C, the distance detector 610 receives the image data from the sensor 600 and detects the rising and falling edges of the image data, so as to calculate the length d1 between the printing start point 720 and the edge of the medium 410, the edge and the first- The edge-area distance d2 between the second actual printing area, and the length d3 of the first-second actual printing area.

Here, c1, c2, and c3 are used to indicate the preparatory printing area, and d1, d2, and d3 are used to indicate the actual printing area.

FIG. 9 is a specific block diagram showing an embodiment of the offset calculator shown in FIG. 4; FIG. 14 is a specific flowchart showing an embodiment of the position offset calculation operation shown in FIG.

Referring to FIGS. 9 and 14 , the offset calculator 430 includes a storage controller 900 , a memory 910 , a difference calculator 920 , an offset output unit 930 , a compensation value calculator 940 and an offset correction device 950 . The operation of the offset calculator 430 will now be described with reference to FIG. 14 .

The memory controller 900 controls the memory 910 to store the first and second pre-printing areas on which the first and second patterns will be printed, respectively. In addition, when the first pattern is printed on the medium 410 , the memory controller 900 controls the memory 910 to store the first actual printing area detected by the area detector 420 . Likewise, when the first and second patterns are printed on the medium 410 , the memory controller 900 controls the memory 910 to store the first-second actual printing areas detected by the area detector 420 .

In operation 1400, the difference calculator 920 calculates a first center position based on the first pre-print area stored in the memory 910, calculates a second center position based on the first and second pre-print areas stored in the memory 910, And calculate the preparatory area difference between the first center position and the second center position.

In operation 1410, the difference calculator 920 calculates a first center position based on the detected first actual print area stored in the memory 910, calculates a second center position based on the detected first-second actual print area, And calculate the actual printing area difference between the first center position and the second center position. Here, the detected first actual printing area is the actual printing area of the first pattern, and the detected first-second actual printing areas are the actual printing areas of the first and second patterns.

In operation 1420, the offset output unit 930 compares the difference between the preparatory area calculated in operation 1400 and the actual printing area difference calculated in operation 1410 to calculate the actual print area difference between the first and second sides of the medium 410. Positional offset between print areas. Using the center positions of the pre-printing area and the actual printing area can reduce the error of the edge detection position, which will occur between the rising edge and the falling edge of the image data due to the performance problem of the sensor 600 .

In operation 1430, the compensation value calculator 940 calculates an edge-area distance difference between the first edge-area distance and the second edge-area distance. Here, the first edge-area distance represents the distance between the edge of the medium 410 and the detected first actual printing area, and the second edge-area distance represents the distance between the edge of the medium 410 and the detected first-second actual printing area. distance between. In operation 1440 , the offset correcting means 950 corrects the position offset calculated in operation 1420 using the edge-area distance difference calculated in operation 1430 . Through operation 1440, an error due to a surface gap between the sensor 600 and the medium 410 may be compensated.

Figure 10 illustrates an embodiment of a method of calculating a positional offset between first and second actual print areas of a medium. The upper view shows an example of a pre-print area of the first and second patterns, while the lower view shows image data obtained by detecting the first and second patterns printed on the media.

Referring to FIG. 10, the first and second pre-printing areas have the same length a3 and they overlap each other with half their lengths. The length e1 represents the difference between the centerline 1000 of the first preliminary printing area and the centerlines 1010 of the first and second preliminary printing areas. The length e2 represents the actual printing area difference between the centerline 1020 of the first actual printing area and the centerlines 1030 of the first-second actual printing areas. The difference of (e2-e1) represents the positional shift between the difference of the preparation area and the difference of the actual printing area.

The length b2 represents the first edge-area distance from the edge of the medium 410 to the detected first actual printing area, and the length d2 represents the distance from the edge of the medium 410 to the detected first-second actual printing area The second edge-area distance of . In order to compensate for the error caused by the surface gap between the sensor 600 and the medium 410 while printing the first and second sides of the medium 410, the positional offset can be corrected by increasing the edge-area distance difference (d2-b2) (e2-e1).

FIG. 15 is a block diagram of the configuration of an alignment correction apparatus according to another embodiment of the present invention, and FIG. 22 is a flowchart of a method of correcting image alignment according to another embodiment of the present invention.

Referring to FIGS. 15 and 22 , the alignment correction device includes a pattern printer 1500 , an area detector 1520 , an offset calculator 1530 and a correction device 1540 . The operation of such an alignment correction device will now be described with reference to FIG. 22 .

In operation 2200 , the pattern printer 1500 prints first and second patterns on the first side of the medium 1510 . In operation 2210 , the pattern printer 1500 prints a third pattern on the second side of the medium 1510 . In operation 2220, the area detector 1520 detects actual printing areas of the first, second, and third patterns on the medium 1510 through sensors.

In one embodiment of the present invention, the first, second and third patterns may have rectangular shapes which are easy to detect. In addition, the first, second and third patterns can be set to be printed at fixed distance intervals from each other, which makes it easy to calculate the actual print area offset (positional offset) between the actual print areas on the first and second sides of the medium 1510. ).

In operation 2230 , the offset calculator 1530 calculates a positional offset between the actual printing areas of the first and second sides of the medium 1510 by comparing the actual printing areas detected in operation 2220 .

In operation 2240, the correcting device 1540 corrects the pre-printing areas of the first and second sides of the medium 1510 based on the above-mentioned calculated positional offset. For example, if the actual printing area of the first side of the medium 1510 exceeds the actual printing area of the second side of the medium 1510 by 0.1mm, then the printing start point of the first side of the medium 1510 is corrected backward by 0.1mm, or the second side of the medium 1510 The printing starting point of the printing is corrected forward by 0.1mm.

FIG. 16 is a block diagram showing an embodiment of the pattern printer shown in FIG. 15; FIG. 23 is a specific flowchart showing an example of the operation of the pattern printer shown in FIG.

Referring to FIGS. 16 and 23 , the pattern printer 1500 includes a printing controller 1600 , a conveying device 1610 and a thermal printing head 1620 . The operation of such a pattern printer 1500 will now be described with reference to FIG. 23 .

In operation 2300, the printing controller 1600 controls the conveying device 1610 to convey the medium 1510 in a backward direction along the printing direction until the medium 1510 reaches a preset printing start point. In order to convey the medium 1510 to the starting point by the conveying device 1610, a sensor may be used to detect the edge of the medium 1510 when the medium 1510 reaches the starting point.

In operation 2310, the printing controller 1600 controls the conveying device 1610 to convey the medium 1510 from the printing starting point by a predetermined length L1 in the printing direction. Next, the thermal printhead 1620 applies heat to the first side of the conveying medium 1510 to print a first pattern on the first side in operation 2320 . After the first pattern is printed, in operation 2330 , the conveying device 1610 further conveys the medium 1510 by a predetermined length L2 along the printing direction under the control of the printing controller 1600 . The thermal print head 1620 then applies heat to the first side of the conveying media 1510 to print a second pattern on the first side in operation 2340 .

After the printing of the first and second patterns on the first side of the media 1510 is completed, the thermal print head 1620 is rotated to face the second side of the media 1510 in operation 2350 . In operation 2360, the printing controller 1600 controls the conveying device 1610 to convey the medium 1510 to the printing start point in a backward direction of the printing direction.

In operation 2370, the printing controller 1600 controls the conveying device 1610 to convey the medium 1510 from the printing starting point by a predetermined length L3 in the printing direction. Next, the thermal printhead 1620 applies heat to the second side of the conveying media 1510 to print a third pattern on the second side in operation 2380 .

FIG. 17 is a block diagram showing an embodiment of the area detector shown in FIG. 15, and FIG. 24 is a flowchart showing an example of the operation of detecting an actual printing area shown in FIG. 22.

Referring to FIG. 17 and FIG. 24 , the area detector 1520 includes a sensor 1700 and a distance detector 1710 . The operation of such an area detector 1520 will now be described with reference to FIG. 24 .

In operation 2400, when the medium 1510 is conveyed to the sensor 1700 by the conveying device 1610, the sensor 1700 detects the pattern printed on the medium 1510 and converts it into image data.

In operation 2410, the distance detector 1710 receives image data from the sensor 1700 and detects a change in the image data. The distance detector 1710 can detect rising and falling edges of image data.

In operation 2420, the distance detector 1710 detects the position of the actual printing area on the medium 1510 by calculating the distance between the above-mentioned changes of the image data. An encoder (not shown) may be mounted on the drive roller 335, driven roller 340, or pressure roller 305 to generate an electrical signal in response to the rotation of the roller, and the distance detector 1710 may use the electrical signal to calculate the detected The moving distance of the medium 1510 between the above image data changes.

18A and 18B are views of an embodiment of a method of printing first and second patterns on a first side of media. FIG. 18A is a schematic view showing the configuration of the printer, and FIG. 18B is a view showing an embodiment of the first and second patterns printed on the first side of the medium.

Referring to FIG. 18A , the conveying device 1610 includes a pressing roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . The conveying device 1610 conveys the medium 1510 to the printing starting point 1820 until the edge detection sensor 1800 detects the edge of the medium 1510, and then, while the conveying device 1610 conveys the medium 1510 from the printing starting point 1820 along the printing direction, the first and second A pattern is printed on a first side of media 1510 .

Referring to FIG. 18B, the first and second patterns may be the same rectangle.

19A and 19B are views of an embodiment of a method of printing a third pattern on a second side of media. Figure 19A is a schematic view of a printer configuration, and Figure 19B is a view of an embodiment of a third pattern printed on the second side of the media.

Referring to FIG. 19A , the conveying device 1610 includes a pressing roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . After printing the first and second patterns on the first side of the medium 1510 , the conveying device 1610 conveys the medium 1510 to the printing start point 1820 again. Starting from starting point 1820 , transport device 1610 transports medium 1510 again along the printing direction to print a third pattern on the second side of medium 1510 .

Referring to FIG. 19B , the third pattern may have an exemplary rectangular shape like the first and second patterns. In addition, the first, second and third patterns are printed in such a manner that the distance between the first and second patterns may be equal to the distance between the second and third patterns.

FIG. 20 is a block diagram of an embodiment of the offset calculator shown in FIG. 15 , and FIG. 25 is a flowchart of an embodiment of the calculation operation of the position offset shown in FIG. 22 .

Referring to FIGS. 20 and 25 , the offset calculator 1530 includes a controller 2000 , a recording medium 2010 , a difference calculator 2020 and an offset output unit 2030 . The operation of the offset calculator 1530 will now be described with reference to FIG. 25 .

The controller 2000 controls the recording medium 2010 to store the actual printing areas of the first, second and third patterns detected by the area detector 1520 .

In operation 2500, the difference calculator 2020 reads out actual printing areas of the first, second, and third patterns from the recording medium 2010, and calculates center positions of these actual printing areas. In operation 2510, the difference calculator 2020 calculates a first-second distance value between the center position of the actual printing area of the first pattern and the center position of the actual printing area of the second pattern. In operation 2520, the difference calculator 2020 calculates a second-third distance value between the center position of the actual printing area of the second pattern and the third pattern.

In operation 2530, the offset output unit 2030 calculates the difference (center distance difference) between the first-second distance value and the second-third distance value to obtain the actual distance between the first and second sides of the medium 1510. positional offset between printing areas, and then the offset output unit 2030 outputs the positional offset. Since the above-mentioned first-second distance value and second-third distance value are used to obtain the position offset, the sensor error between the rising edge and the falling edge of the image data output by the sensor 1700 can be reduced.

21A to 21D are diagrams of an embodiment of a method of calculating a position offset between actual print areas of first and second sides of media. FIG. 21A is a schematic view of a printer in which a pattern is printed on media 1510 and the actual printed area of the pattern is detected by sensor 1700 . The conveying device 1610 includes a pressure roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . 21B is a view of an embodiment of a first, second, and third pattern printed on a first and second side of media 1510. Referring to FIG. 21B, the first, second and third patterns are rectangles of the same size. In addition, the distance between the first pattern and the second pattern is equal to the distance between the second pattern and the third pattern.

FIG. 21C shows the simulated output signals of sensor 1700 in response to the first, second and third patterns printed on media 1510 . Figure 21D shows the digital output signal of sensor 1700 corresponding to the analog output signal shown in Figure 21C. Whenever the analog output signal is equal to the digital reference value "Vrref1", a rising or falling edge occurs in the digital output signal.

21A to 21D, the length a represents the distance between the edge of the medium 1510 and the centerline (position) 1000 of the first pattern actual print area, and the length b represents the distance between the edge of the medium 1510 and the centerline (position) of the second pattern actual print area ( position) 1010, and the length c represents the distance between the edge of the medium 1510 and the centerline (position) 1020 of the actual printing area of the third pattern. By subtracting the length a from the length b, the first-second distance value A can be obtained; and by subtracting the length b from the length c, the second-third distance value B can be obtained.

Since the first, second, and third patterns described above are set to be spaced side by side at the same distance, the two distance values A and B being equal indicate that there is no positional offset between the actual printed areas of the first and second sides of the medium 1510 . Therefore, by calculating the difference (center distance difference) between the first-second distance value and the second-third distance value, the position offset can be obtained.

FIG. 26 is a block diagram showing the configuration of an alignment correction apparatus according to still another embodiment of the present invention, and FIG. 34 is a flowchart of an image alignment correction method according to still another embodiment of the present invention.

Referring to FIG. 26 and FIG. 34 , the alignment correction device includes a delivery device 2600 , an analog signal generator 2620 , an offset calculator 2630 and an offset correction device 2640 . The operation of this alignment correction device will now be described with reference to FIG. 34 .

In operation 3400 , the conveying device 2600 loads the medium 2610 along the first conveying channel, and the analog signal generator 2620 detects the loading of the medium 2610 . In operation 3410 , the analog signal generator described above stores a first analog signal generated by the sensor in response to the loading of the medium 2610 .

In operation 3420 , the conveying device 2600 loads the medium 2610 along the second conveying channel, and the analog signal generator 2620 detects the loading of the medium 2610 . In operation 3430 , the analog signal generator 2620 stores a second analog signal generated by the sensor in response to the loading of the medium 2610 .

In operation 3440, the offset calculator 2630 calculates a positional offset between the actual print areas of the first and second sides of the medium 2610 using the first and second analog signals. Since the distance between the medium 2610 and the sensor for placing the medium 2610 at the print start point varies according to the loading path (first and second delivery paths) of the medium 2610, the print start points of the first and second sides of the medium 2610 are not consistent, thereby causing a positional offset between the actual print areas on the first and second sides of the media 2610.

In operation 3450 , the calibration device 2640 performs calibration on the pre-print areas of the first and second sides of the medium 2610 . For example, if the first pattern printed on the first side of the medium 2610 exceeds the second pattern printed on the second side of the medium 2610 by 0.1mm, then the printing start point of the first side of the medium 2610 is corrected backward by 0.1mm, or the medium The print start point of the second side of the 2610 is corrected forward by 0.1mm.

FIG. 27 is a block diagram showing an embodiment of the analog signal generator shown in FIG. 26 . Referring to FIG. 27 , the analog signal generator 2620 includes a sensor 2700 , a controller 2710 and a recording medium 2720 .

When the medium 2610 is loaded along the first conveying channel, the sensor 2700 detects the medium 2610 and outputs a corresponding first analog signal. The controller 2710 stores the above-mentioned first analog signal in the recording medium 2720 . The recording medium 2720 may include a ring queue buffer (RQB, ring queue buffer), which stores a predetermined part of the analog signal centered on the edge of the analog signal.

28A to 28D are views of an embodiment of a method of detecting media using a sensor as it is being loaded along a first delivery path. 28A is a schematic view of a printer in which a first analog signal is generated by a sensor in response to loading of media along a first transport path. In FIG. 28A , the conveying device 1610 includes a pressure roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . Figure 28B shows media detected by an edge detection sensor. The media 2610 is loaded onto the first transport path by the driven roller 340 and the drive roller 335 , and the edge detection sensor 1800 outputs a signal in response to the loading of the media 2610 .

The output signal of the edge detection sensor 1800 includes an analog signal and a digital signal. FIG. 28C shows a first analog signal of edge detection sensor 1800 in response to loading of media 2610 , while FIG. 28D shows a first digital signal of edge detection sensor 1800 in response to loading of media 2610 . The medium 2610 is further conveyed by a predetermined length from the position where the edge appears in the first digital signal so that the medium reaches the printing start point 1820 .

29A to 29D are views showing an embodiment of a method of detecting a medium using a sensor when the medium is loaded along the second transport path. 29A is a schematic view of a printer in which a second analog signal is generated by a sensor in response to loading of media along a second transport path. In FIG. 29A , the conveying device 1610 includes a pressure roller 305 , a driving roller 335 , a driven roller 340 , an output driven roller 365 , an output roller 370 and a pick-up roller 380 . Figure 29B shows media detected by an edge detection sensor. The media 2610 is loaded to the second transport path by the driven roller 340 and the driving roller 335 , and the edge detection sensor 1800 outputs a signal in response to the loading of the media 2610 .

FIG. 29C shows a second analog signal from edge detection sensor 1800 in response to loading of media 2610 , while FIG. 29D shows a second digital signal from edge detection sensor 1800 in response to loading of media 2610 .

Referring to FIGS. 28A and 29A , the distance between the medium 2610 and the edge detection sensor 1800 varies according to the loading path (first conveying path and second conveying path) of the medium 2610, which results in a first analog signal of the edge detecting sensor 1800 and the difference between the second analog signal. Therefore, the edge position of the first analog signal in FIG. 28D is not equal to the edge position of the second analog signal in FIG. 29D , so the position of the printing start point 1820 changes with the change of the side of the medium 2610 .

FIG. 30 is a block diagram showing an embodiment of the offset calculator shown in FIG. 26, and FIG. 35 is a flowchart showing an embodiment of the position offset calculation operation shown in FIG.

Referring to FIGS. 30 and 35 , the offset calculator 2630 includes a ratio calculator 3000 and a distance calculator 3010 . The operation of the offset calculator 2630 will now be described with reference to FIG. 35 .

In operation 3500, the ratio calculator 3000 receives the first and second analog signals generated by the analog signal generator 2620 and calculates an output ratio of the first analog signal relative to the second analog signal. Figure 31 shows an exemplary simulated signal from a sensor in response to media loading. Referring to Figure 31, the graphical shape of the sensor's analog signal is not affected by the distance between the medium and the sensor. Therefore, the output ratio of the first signal relative to the second signal will not change with the change of the distance between the medium and the sensor. The highest points of the first and second analog signals can be used to obtain the output ratio. Furthermore, a point at a predetermined distance from the edge of the digital signal may be defined as the highest point of the analog signal.

In operation 3510, the distance calculator 3010 calculates a distance between edges of the first and second digital signals using an output ratio of the first analog signal to the second analog signal. Here, the distance calculated in operation 3510 is the positional offset between the actual printing areas of the first and second sides of the medium.

Fig. 32 is a block diagram showing an embodiment of a distance calculator shown in Fig. 30; Fig. 33 is a graph showing a method for calculating a position offset by using an analog signal of a sensor according to the present invention; Fig. 36 is a specific flow chart showing An example of calculation operations for positional offsets shown in FIG. 34 .

Referring to FIGS. 32 , 33 and 36 , the distance calculator 3010 includes a reference calculator 3200 , a position extractor 3210 and a position distance calculator 3220 . The operation of such a distance calculator will now be described with reference to FIGS. 33 and 36 .

In operation 3600, the reference calculator 3200 receives the output ratio (M1:M2) of the first analog signal to the second analog signal from the ratio calculator 3000 to calculate an imaginary reference value Vref2 using the following formula 1:

Formula 1

Vref1: Vref2 = M1: M2

Where Vref1 is a digital reference value, which represents the point of the analog signal when an edge occurs in the digital signal. The digital reference value Vref1 is preset in the sensor.

In operation 3610, the position extractor 3210 extracts a first position having the aforementioned imaginary reference value Vref2 from the first analog signal.

In operation 3620, the positional distance calculator 3220 uses the positional distance between the first position and the second position having an imaginary reference value Vref2 in the second analog signal to calculate the distance between the actual printing areas of the first and second sides of the medium. position offset.

More specifically (see FIG. 33 ), the location distance calculator 3220 calculates a location distance A between a first location and a second location having the same imaginary distance A in the first and second analog signals. Reference value Vref1. Since the length β between points having the same value as the digital reference value Vref1 in the first and second analog signals is equivalent to the distance between the edges of the first and second digital signals, the position distance calculator 3220 converts the The calculated positional distance A is used as an approximation of the length β or the length β is calculated using the following formula 2 to obtain the positional offset between the actual printing areas of the first and second sides of the medium.

Formula 2

Vref2: Vref1 = A: β

As above, by comparing the pre-printed areas of patterns on the first and second sides with the actual printed areas detected by the sensor, the positional deviation of the actual printed areas on the first and second sides of the medium can be calculated. The pre-printing area is corrected using the calculated positional offset, whereby the alignment between the actual printing areas of the first and second sides can be corrected accurately and conveniently. In addition, the center position of the pre-printing area and the actual printing area is used to calculate the position offset, thereby compensating for errors caused by surface gaps between the sensor and the media and sensor performance issues.

The present invention can also be embodied as computer readable codes in a computer readable recording medium. The computer readable recording medium may be any data storage device that can store data which can be thereafter read by a computer system. Examples of such computer readable recording media include read only memory (ROM), random access memory (RAM), optical disk ROM, magnetic tape, floppy disk, optical data storage, and carrier waves (such as for transferring data via the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for realizing the present invention can be easily derived by those skilled in the art to be suitable for the present invention.

Although the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood that various changes in form and details may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims. . The above-described exemplary embodiments should be used as explanations, not limitations. Therefore, the scope of the invention is defined by the appended claims rather than the detailed description of the invention, and all differences within the scope will be included in the present invention.

This application claims priority to Korean Patent Applications No. 10-2004-0060112 and No. 10-2004-0070618 filed with the Korean Intellectual Property Office on July 30, 2004 and September 4, 2004, the entire contents of which incorporated herein by reference.

Claims (53)

1. A method of correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing, the method comprising: After printing the first pattern on the first pre-print area on the first side of the medium, using a sensor to detect the first actual print area on the first side of the medium; After printing the second pattern on the second pre-printing area on the second side of the medium, using a sensor to detect the first-second actual printing area of the medium; Using the first pre-printing area, the second pre-printing area, the detected first actual printing area and the detected first-second actual printing area, calculate the distance between the actual printing areas of the first and second sides The positional offset of ; and Using the calculated position offset, the printing position of the first or second side of the medium is corrected. 2. The method of claim 1, wherein each detection operation step comprises: receiving image data from the medium of the sensor; determining a change in the image data; and The actual print area is detected using the determined changes in the image data. 3. The method of claim 2, wherein The change in the image data is a rising or falling edge of the image data. 4. The method of claim 1, wherein The step of correcting the printing position is performed by correcting a first heating start point at which the thermal printhead starts applying heat to the first side of the medium or correcting a second heating start point at which the thermal printhead starts applying heat to the second side of the medium . 5. A method of correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing, the method comprising: After printing the first pattern on the first pre-print area on the first side of the medium, using a sensor to detect the first actual print area on the first side of the medium; After printing the second pattern on the second pre-print area on the second side of the media, a sensor is used to detect the first-second actual print area of the media, the second pre-print area is identical to the first print area on the first side of the media The ready-to-print areas overlap; Using the first pre-printing area, the second pre-printing area, the detected first actual printing area and the detected first-second actual printing area, calculate the distance between the actual printing areas of the first and second sides The positional offset of ; and Using the calculated position offset, the printing position of the first or second side of the medium is corrected. 6. The method of claim 5, wherein The thermal printhead rotates to face the first side and the second side of the media. 7. The method of claim 5, wherein Each of the patterns has a polygonal shape. 8. The method of claim 5, wherein the steps of each detection operation include: receiving image data from the medium of the sensor; determining a change in the image data; and The actual print area is detected using the determined changes in the image data. 9. The method of claim 8, wherein The change in the image data is a rising or falling edge of the image data. 10. The method of claim 5, wherein said step of calculating a position offset comprises: calculating a pre-print difference between a center of the first pre-print area and a center of the second pre-print area; calculating the actual printing area difference between the detected first actual printing area center and the detected first-second actual printing area center; The position offset is calculated by using the calculated preparatory area difference and the actual printing area difference. 11. The method of claim 10, further comprising: calculating the edge-area distance difference between the first edge-area distance and the second edge-area distance, wherein the first edge-area distance is the distance from the edge of the medium to the first actual print area, so said second edge-area distance is the distance from the edge of the medium to said first-second actual print area, said edge and actual print area being detected during said detection operation; and The position offset is corrected by using the edge-area distance difference. 12. The method of claim 5, wherein The step of correcting the printing position is performed by correcting a first heating start point at which the thermal printhead starts applying heat to the first side of the medium or correcting a second heating start point at which the thermal printhead starts applying heat to the second side of the medium . 13. An apparatus for correcting image registration of an imaging device configured with a thermal printhead for printing by applying heat to first and second sides of media, the apparatus comprising: a pattern printer for printing a first pattern on a first pre-print area on the first side of the medium, and printing a second pattern on a second pre-print area on the second side of the medium; Area detector, used to detect the actual printing area of the medium; an offset calculator, configured to compare the preliminary printing area with the actual printing area detected by the area detector to calculate a positional offset between the actual printing areas on the first and second sides of the medium; as well as A correction device, which uses the calculated position offset to correct the printing position of the first or second side of the medium. 14. The apparatus of claim 13, wherein the pattern printer comprises: Conveying device for conveying medium; a thermal printhead for applying heat to the first and second sides of the media to perform a printing operation; a print controller for controlling the conveying device and the thermal print head to print a first pattern on a first pre-print area on the first side of the medium, and print a second pattern on a second pre-print area on the second side of the medium. pattern. 15. The apparatus of claim 14, further comprising: A printhead positioner for rotating the thermal printhead so that the thermal printhead faces the first and second sides of the media. 16. The apparatus of claim 13, wherein Each of the patterns has a polygonal shape. 17. The apparatus of claim 13, wherein said area detector comprises: a sensor for detecting an image from the medium and outputting corresponding image data, and A distance detector for determining changes in said image data and thereby detecting distances between the changes. 18. The apparatus of claim 17, wherein The distance detector determines changes in the image data and detects distances between the changes by using an encoder. 19. The method of claim 17, wherein The change in the image data is a rising or falling edge of the image data. 20. The apparatus of claim 13, wherein the offset calculator comprises: a memory for storing the pre-printing area of the detected actual printing area; a storage controller configured to control the memory to store the first preliminary printing area, the second preliminary printing area, and the first actual printing area detected by the area detector after the first pattern is printed on the medium , and the first-second actual printing area detected by the area detector after the first and second patterns are printed on the medium; A difference calculator, configured to calculate the difference between the center of the first pre-printing area and the center of the second pre-printing area, and calculate the difference between the detected center of the first actual printing area and the center of the second pre-printing area. the actual print area difference between the detected centers of the first-second actual print area; and An offset output unit, configured to calculate the position offset by using the calculated difference between the prepared area and the actual printed area. 21. The apparatus of claim 20, further comprising: A compensation value calculator for calculating a difference in edge-area distance between a first edge-area distance and a second edge-area distance, wherein the first edge-area distance is from the edge of the media to the first actual print area distance, and the second edge-area distance is the distance from the edge of the media to the first-second actual print area; and offset correcting means for correcting the position offset calculated by the offset output unit by using the calculated edge-area distance difference. 22. The apparatus of claim 13, wherein The correcting device uses the calculated positional offset to correct the first heating start point at which the thermal print head starts to apply heat to the first side of the medium, or the point at which the thermal print head starts to apply heat to the second side of the medium The second heating start point is corrected. 23. A computer-readable recording medium having a computer-readable program for executing the method of claim 1. 24. A computer-readable recording medium having a computer-readable program for executing the method of claim 5. 25. A method of correcting image registration of an imaging device, wherein a thermal printhead applies heat to a first side of the media after loading the media along a first transport path, and after loading the media along a second transport path A thermal printhead applies heat to the second side of the media, the method comprising: When the medium is loaded along the first conveying channel, the medium is detected by a sensor, and a first analog signal output by the sensor is stored in a recording medium; When the medium is loaded along the second conveying channel, the medium is detected by the sensor, and a second analog signal output by the sensor is stored in the recording medium; using said first and second analog signals stored in the recording medium to calculate a positional offset between the actual print areas of the first and second sides of the medium; and Using the calculated position offset, the printing position of the first or second side of the medium is corrected. 26. The method of claim 25, wherein The thermal printhead rotates to face the first and second sides of the media. 27. The method of claim 25, wherein Each of the first and second analog signals is output by detecting a predetermined portion of the medium, the predetermined portion including an edge of the medium. 28. The method of claim 25, wherein the step of calculating a position offset comprises: calculating an output ratio of the first analog signal to the second analog signal; and The position offset is calculated using the calculated output ratio. 29. The method of claim 28, wherein using the calculated output ratio to calculate a position offset comprises: calculating an imaginary reference value by multiplying said calculated output ratio by a digital reference value of said sensor; detecting a location in the stored first analog signal having said imaginary reference value; and A position offset is calculated between the detected position and the position having the digital reference value in the stored second analog signal. 30. The method of claim 28, wherein using the calculated output ratio to calculate a position offset comprises: obtaining an imaginary reference value by multiplying said calculated output ratio by a digital reference value of said sensor; detecting a location in the stored second analog signal having said imaginary reference value; and A position offset is calculated between the detected position and the position having the digital reference value in the stored first analog signal. 31. The method of claim 25, wherein The step of correcting the printing position is performed by correcting the first heating starting point at which the thermal print head starts applying heat to the first side of the medium or correcting the second heating starting point at which the thermal printing head starts applying heat to the second side of the medium of. 32. A method of correcting image registration of an imaging device configured with a thermal printhead that applies heat to first and second sides of media for printing, the method comprising: printing first and second patterns, respectively, on first and second pre-print areas on the first side of the media; After printing the third pattern on the third pre-printing area on the second side of the medium, detecting the actual printing areas of the first to third patterns by a sensor; calculating an offset between the actual print positions of the first and second sides using the detected actual print area; and Using the calculated offset, the printing position of the first or second side of the medium is corrected. 33. The method of claim 32, wherein The thermal printhead rotates to face the first and second sides of the media. 34. The method of claim 32, wherein The first, second and third pre-print areas are spaced apart from each other by the same distance. 35. The method of claim 32, wherein the step of detecting the actual print area comprises: receiving image data from the medium of the sensor; determining a change in the image data; and The actual print area of the medium is detected through the determined changes in the image data. 36. The method of claim 35, wherein A change in the image data is a rising or falling edge of the image data. 37. The method of claim 32, wherein said step of calculating a position offset comprises: calculating a first-second distance value between the centers of the detected first and second patterns; calculating a second-third distance value between the centers of the detected second and third patterns; and calculating a center distance difference between the first-second difference and the second-third difference. 38. An apparatus for correcting image registration of an imaging device, wherein the thermal head applies heat to a first side of the media when the media is loaded along a first transport path, and when the media is loaded along a second transport path A rear thermal printhead applies heat to the second side of the media to perform printing on the first and second sides of the media, the apparatus comprising: Conveying device for conveying medium; an analog signal generator for detecting the medium as it is transported along said first and second conveying channels to generate corresponding first and second analog signals; an offset calculator that uses the first and second analog signals to calculate an offset between the actual print areas of the first and second sides of the media; and A correction device, which uses the calculated position offset to correct the printing position of the first or second side of the medium. 39. The apparatus of claim 38, wherein The thermal printhead rotates to face the first and second sides of the media. 40. The apparatus of claim 38, wherein Each of the first and second analog signals is output by detecting a predetermined portion of the medium, the predetermined portion including an edge of the medium. 41. The apparatus of claim 38, wherein the analog signal generator comprises: sensors for detecting the medium as it is transported along said first and second conveying channels to generate said respective first and second analog signals; a recording medium for storing said first and second analog signals; and A controller for controlling storage of the first and second analog signals in a recording medium. 42. The apparatus of claim 38, wherein the offset calculator comprises: a ratio calculator for calculating the output ratio of the first analog signal to the second analog signal; as well as a distance calculator for calculating the position offset by the calculated output ratio. 43. The apparatus of claim 42, wherein the distance calculator comprises: a reference calculator that calculates an imaginary reference value by multiplying said calculated output ratio by said sensor's digital reference value; a position detector for detecting a position having said imaginary reference value in the stored first analog signal; and A position distance calculator, which calculates the position offset using the detected position and the position having the digital reference value in the stored second analog signal. 44. The apparatus of claim 42, wherein the distance calculator comprises: a reference calculator that calculates an imaginary reference value by multiplying said calculated output ratio by said sensor's digital reference value; a position detector for detecting a position having said imaginary reference value in the stored second analog signal; and A position distance calculator, which calculates the position offset using the detected position and the position having the digital reference value in the stored first analog signal. 45. An apparatus for correcting image registration of an imaging device configured with a thermal printhead for printing by applying heat to first and second sides of media, the apparatus comprising: a pattern printer that prints first and second patterns on the first side of the media and a third pattern on the second side of the media; An area detector to detect the actual print area of the media; an offset calculator for comparing the actual print area detected by the area detector to calculate an offset between the actual print positions of the first and second sides of the medium; and Correction means for correcting the printing position of the first or second side of the media using the calculated offset. 46. The apparatus of claim 45, wherein The first, second and third patterns are spaced apart from each other by the same distance. 47. The apparatus of claim 45, wherein the pattern printer comprises: Conveying device for conveying medium; a thermal printhead that applies heat to the first and second sides of the media to perform a printing operation; and a print controller for controlling the conveying device and the thermal printhead to print the first and second patterns on the first and second pre-print areas on the first side of the medium, and print the first and second patterns on the first and second pre-print areas on the second side of the medium The third pattern is printed on the preparatory printing area. 48. The apparatus of claim 47, further comprising: A printhead positioner for rotating the thermal printhead so that the thermal printhead faces the first and second sides of the media. 49. The apparatus of claim 45, wherein said area detector comprises: a sensor for detecting an image from the medium and outputting corresponding image data; and A distance detector for determining changes in said image data to detect distances between the changes. 50. The apparatus of claim 49, wherein A change in the image data is a rising or falling edge of the image data. 51. The apparatus of claim 45, wherein the offset calculator comprises: a memory for storing the detected actual printing area; a controller configured to control the recording medium to store the actual printing area detected by the area detector after the first, second and third patterns are printed on the medium; a difference calculator for calculating a first-second distance value between the detected centers of the first and second patterns and a second-third distance between the detected centers of the second and third patterns value; and An offset output unit, configured to output the difference between the first-second distance value and the second-third distance value. 52. A computer-readable recording medium having a computer-readable program for executing the method of claim 25. 53. A computer-readable recording medium having a computer-readable program for executing the method of claim 32.

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