JPH05221069A - Method for correction of shear in printing of printer - Google Patents

Abstract

PURPOSE:To enable shear in printing to be automatically corrected by a method wherein printing of a printer is read with a camera, a quantity of shear is calculated to determine a quantity to be corrected, the correction data is transmitted to the printer to be stored in the printer, and an alignment regulation mechanism is controlled by the stored correction data to perform correction of the shear in printing. CONSTITUTION:In a printer 31 having an alignment regulation mechanism which corrects shear in printing, a printing pattern 40 for checking is printed with a printer 31 and besides, the printing is read as an image data with a camera 36. A quantity of shear calculated with an image microprocessor 34 to determine a quantity to be corrected. Means 33, 32 which transmit the quantity to be corrected as a correction data to the printer 31, and a means which stores the correction data transmitted to the printer 31 side in the printer 31, are provided. Then, an alignment regulation mechanism is controlled by the correction data stored in the printer to perform correction of the shear in printing. Consequently, automatic correction of the shear in printing comes to be capable of being performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of correcting print deviation in a printer.

[0002]

2. Description of the Related Art FIG. 9 is an external view showing an example of a conventional serial dot printer using an impact type dot print head. In FIG. 9, the printer 1 is
The data to be printed is received from a microcomputer (not shown) or the like, and this data is printed by using the print head 4 (see FIG. 10).

FIG. 10 is a structural layout diagram schematically showing the internal structure of the printer 1 shown in FIG. In FIG. 10, a control board 12 having a microprocessor 10 and a Centronics connector 11 mounted thereon is arranged on the rear side of the printer 1, and a platen 3 around which a printing paper 2 is wound at a printing position, A print head 4 and the like arranged opposite to the platen 3 are arranged. Also,
The platen 3 is rotated by a paper feed motor 5 as a drive source, and the print head 4 is reciprocally movable in the left-right direction along the axis of the platen 3 by a space motor 6 as a drive source. The structure for supporting the print head 4 and the space motor 6 is roughly as shown in FIG. That is, the print head 4 is mounted on the space motor 6 so as to be integrally movable, and the front portion of the space motor 6 is slidably held by the carriage shaft 7. In addition, the output shaft 6 of the space motor 6
The output gear 8 (see also FIGS. 12 and 13) is integrally rotatably attached to a (see FIGS. 12 and 13), and the output gear 8 is meshed with the teeth of the space rack 9. It has become.

In the printer 1, when print data is sent from the microcomputer, this data is sent to the Centronics connector 1 as an interface.
The data is received at 1 and sent to the microprocessor 10, and the microprocessor 10 performs data processing. Further, based on the processing result, the space motor 6 and the paper feed motor 5 are driven to move the print head 4 to the carriage shaft 7.
The print head 4 is configured to print by moving the print head 4 to a predetermined position.

FIG. 12 shows the structure of the space motor 6 in the peripheral portion in more detail, and FIG. 13 shows the space motor 6 shown in FIG.
FIG. 3 is a schematic configuration perspective view showing a detection mechanism for detecting the position and speed of a movable part in the space motor 6 on which the print head 4 is mounted. 12 to 14,
In addition to the print head 4, the space motor 6 is provided with the output gear 8 and a slit plate 14 that rotates integrally with the output gear 8. Further, the slit plate 14 has
A plurality of slits 14a are formed at substantially equal intervals in the rotation direction. In addition, in the vicinity of the slit plate 14, the photo sensor 1 is configured such that the slit 14a is sandwiched in the vertical direction.
5 are provided. The photo sensor 15 includes a light emitting source 15A and a photomulticoupler 15B, and the light emitting source 1
The sensor output 16 is determined by whether the light emitted from 5A is received by the photomulticoupler 15B through the slit 14a.
Is configured to be input to.

FIG. 15 is a waveform diagram showing an example of the sensor output 16 of the photosensor 15, with the vertical axis representing the output voltage [V].
And the horizontal axis represents time [seconds]. That is, the waveform shown in FIG. 15 corresponds to the slit 1 shown in FIG.
When the interval of 4a is x, the waveform of the sensor output obtained when it takes t [seconds] to move the distance x on the slit plate 14 is shown. Since the microprocessor 10 obtains it, the position and speed of the movable part of the space motor 6 can be detected by the microprocessor 10.

Therefore, in this printer 1, the space motor 6 is driven to move the print head 4 to a predetermined position along the carriage shaft 7, and at the same time, the print head 4 is made to print, for example, as shown in FIG.
As shown in FIG. 3, the horizontal printing can be sequentially performed on the printing paper 2, and the line feed can be performed by driving the paper feeding motor 5.

However, in this printer 1, for example, when printing a vertical bar-shaped figure or the like as shown by reference numeral 17 in FIG. 17, the point indicated by reference numeral 0 in the drawing is set as a certain reference point. In such a case, the distance from the reference point 0 to printing may vary depending on the operation direction of the print head 4 (two directions of arrows a and b in FIG. 17).
That is, in the example of FIG. 17, the first and third lines of printing are printing when the print head 4 is operated in the a direction, and the second line is printing when the printing head 4 is operated in the b direction. In this case, the starting point of each line is at a distance of x1 and x2 from the reference point 0. Originally, the difference x3, that is, the print deviation should be zero, but in reality, there is a small amount of print deviation (difference x
3) occurs. Moreover, when it is attempted to measure this deviation (difference x3), the print that looks like a vertical bar-shaped figure in FIG. You can see that it is a circular lump. Therefore, the difference x3 between the first line and the second line is very difficult to measure because the outer shape of the vertical bar-shaped print has irregularities. The deviation of printing due to the movement direction of the print head 4 is referred to as "alignment" here, and the main cause thereof is that due to the play of the meshing portion between the output gear 8 and the space rack 9. Also, this amount of backlash will be referred to as "backlash" hereinafter. With this backlash, when the output gear 8 starts rotating, if it is closely meshed with the space rack 9 from the beginning,
At the same time when the output gear 8 rotates, the entire movable part including the print head 4 starts to move. However, if there is a backlash when the output gear 8 starts to rotate, the output gear 8 will move to the space rack 9
It will run idle until it is fitted with.

FIG. 19 is a diagram showing displacement-time characteristics in the movable portion of the space motor 6 with and without the backlash. FIG. 19
In, the solid line 18a indicates the case without backlash, and the dotted line 18b indicates the case with backlash. As can be seen from FIG. 19, when there is a backlash shown by the line 18b, the space motor 6 operates for Ts [seconds], but there is a time when the entire movable part does not operate due to the backlash, and the print start position x0 Until line 18a reaches T1 [sec] and line 18b reaches T2 [sec]
It takes. Therefore, if you print at T1 [seconds], line 18
In the case of operation with backlash shown in b, (x0-
Only x1) will be printed at the position x1 before the print start position x0, and the horizontal displacement of the print, that is, the alignment shown in FIG. 18, will occur.

Therefore, in order to prevent this alignment, in the conventional printer, the alignment adjustment is performed as shown in FIG. 20, for example, so that the print deviation x3 becomes zero. FIG. 20 shows an example of a printer system including an internal structure of the printer body, a microcomputer and a keyboard. Further, in FIG. 20, the same reference numerals as those in FIGS. 9 to 19 denote the same as those in FIGS. 9 to 19.

In this system configuration, the alignment adjustment is performed as follows.
First, the microcomputer 19 sends the data of the check print pattern shown in FIG. 18 to the printer 1 through the Centronics cable 20, the printer 1 prints on the print paper 2 based on the print data, and the human ( The measurer) judges the alignment amount by looking at the print. After making the determination, a person inputs a correction amount corresponding to the alignment amount through the keyboard 22. Then, this correction amount is
9, the Centronics cable 20, and the Centronics connector 11 are input to the microprocessor 10,
The correction amount is stored in the memory 23. Next, the microprocessor 10 changes the operation start time of the output gear 8 based on the stored correction amount. That is, in the displacement-time characteristics shown in FIG. 19, when the operation with backlash shown by the line 18b is made to operate earlier by Ts [seconds], the line 1
8b and the line 18a overlap each other, and alignment due to a shift in the movement amount depending on the operation direction is eliminated. After the above correction, the microcomputer 19 prints again as shown in FIG. 18, and a human visually confirms that there is no alignment, and the correction is completed.

This alignment adjustment is the same in a non-impact printer, for example, a printer that oscillates a laser and rotates a polygon mirror to perform printing when the rotation speed of the polygon mirror varies. Even within a print line, there are cases where the print intervals at the edges and the center of the line are different, and the same adjustment as above is required.

[0013]

As described above, according to the conventional method for correcting print deviation, a person measures the relative deviation amount between print lines, that is, the registration amount, and the correction amount is stored in the memory through the microcomputer 19. Since it is input to 23, there is a problem that it takes manpower. Further, there is a problem in that the amount of registration measurement by visual observation varies depending on the measurer and even for the same measurer depending on time and the like, and reproducibility is poor.

The present invention has been made in view of the above problems, and an object thereof is to provide a registration measurement amount that is reproducible even when circumstances such as time and environmental conditions change. It is an object of the present invention to provide a print misregistration correction method for a printer that can measure and perform stable alignment adjustment.

[0015]

In order to achieve the above object, the present invention provides a printer having an alignment adjusting mechanism for correcting print misalignment, which causes the printer to print a check print pattern, and the printer prints the print pattern. A unit for reading the image data, calculating the deviation amount to determine the correction amount, and transmitting the correction amount as correction data to the printer, and the correction data transmitted to the printer side are stored in the printer. And a means for storing the information, and controlling the alignment adjusting mechanism with the correction data stored in the printer to correct the print misalignment.

[0016]

According to this, the printer is caused to print the data for checking the printing deviation, the printing of the printer is automatically read by the camera, the alignment (deviation) amount is detected from the read image data, and this is detected. A correction value corresponding to the alignment amount is automatically transmitted to the printer, this data is stored in the printer as the alignment correction amount, and the stored data is used to control the alignment adjustment mechanism to perform the correction. Therefore, the alignment can be corrected automatically and accurately. As a result, it is possible to perform the correction in a short time, because manpower is not required to perform the correction, reproducibility is obtained.

[0017]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a system configuration to which the present invention is applied. In FIG. 1, in this system, the printer 31 and the printer 31 are connected through a Centronics cable 32 as an interface.
A microcomputer 33 connected to the microcomputer 33, an image processing microprocessor 34 connected to the microcomputer 33, a memory 35, a CCD (solid-state image sensor) camera 36, and the like.

FIG. 2 is a flow chart showing an example of a processing procedure in the case of correcting the print deviation in the system configuration configured as described above. Therefore, the print misalignment correction operation shown in FIG. 1 will be described with reference to the flowchart of FIG.

First, the microcomputer 33 sends registration check print pattern data to the printer 31 to print the print pattern 40 on the print sheet 37 (step ST1). Also, print here C
The image data is read by the CD camera 36 and stored in the memory 3
5 (step ST2). Then, the memory 35
The image data stored in the image processing microprocessor 3
4 is used to calculate the registration amount and its correction amount (step ST3).

From step ST3, the process proceeds to step ST4, and it is determined in step ST4 whether correction is necessary. If the correction is not necessary, the correction process ends. On the other hand, if correction is necessary, the process proceeds to step ST5, the correction amount is fetched into the microcomputer 33, and is stored in the memory (ROM) of the microprocessor (not shown) of the printer 31 through the Centronics cable 32. Further, based on this data, it controls an alignment adjustment mechanism (not shown) in the printer 31,
Correct the print misalignment. Therefore, by performing the processing in this way, the correction can be performed without the need for manpower.

The determination as to whether or not the correction is made in step ST4 is determined from the value of the difference x3 described in FIG. 18 as the above-mentioned conventional technique, and if the value is less than a certain allowable set value, "no correction is necessary". If it is equal to or larger than the allowable set value, it is determined that “correction is necessary”.

Next, the outline of the image processing procedure performed in the image processing microprocessor 34 in FIG. 1 will be described. First, in image processing, the image data read by the CCD camera 36 and stored in the memory 35 is 2
The value conversion process is performed. This binarization process will be further described with reference to FIG. First, (a) of the same figure shows an example of a printing pattern, which is the same as that described in the above-mentioned prior art, and (b) is a binarization process of printing on the code L line in (a). It shows the previous concentration distribution,
(C) shows the density distribution after the binarization process.
The horizontal axis (x axis) in (b) and (c) represents the position, and the vertical axis (y axis) represents the concentration. The density resolution on the vertical axis is determined by the capacity of the memory 35, and has a resolution of 255 gradations in this embodiment. That is, even if the density appears uniform in (a), there is actually a density distribution as in (b), and this is divided by the slice level 38, and the density above the slice level 38 is 255 gradations (black). .. and below are binarized by obtaining the density distribution as shown in (c) by performing processing of 0 gradation (white). By performing the above-described processing, the image processing microprocessor 34 can calculate image data such as area, peripheral tone, center of gravity, and end position of the image (a). Note that there is a commercially available processor for this calculation method, which is well known and will not be described.

FIG. 4 shows the image processing microprocessor 34.
FIG. 6 is a diagram for explaining an example of a method of calculating a registration correction amount when the position of the center of gravity of the calculation result calculated by is used. In FIG. 4, reference numeral G11,
G12, G21, G22, G31, and G32 respectively represent the center of gravity in printing of a vertical bar-shaped figure or the like as (x, y) coordinates with respect to a certain reference point 0. In this case, the difference between the centers of gravity, that is, the amounts of the registrations x1, x2, and x3 is calculated by taking the difference between the data of the respective centers of gravity G11 to G32 as shown in FIG. Moreover, the number of registration measurement samples can be increased by averaging the calculated registrations x1, x2, and x3. When the number of samples is increased in this way, the accuracy of the data is remarkably improved in proportion to the increase in the number of samples.

FIG. 5 shows the image processing microprocessor 34.
FIG. 6 is a diagram for explaining an example of a method of calculating a registration correction amount when the end position of the calculation result calculated by is used. In FIG. 5, the end position here means, as shown in (a) of the same figure, when the vertical line of the x-axis is moved from the origin 0 in the direction in which x gradually increases, the figure first appears. The part of the vertical line x1 that touches the line and the part of the vertical line x2 that touches the end when the number increases further. These pieces of information are obtained by the image processing microprocessor 34 for each image, and from the bar-shaped printing, the symbols E11a, E11b, E12a, E12 in FIG.
b, E21a, E21b, E22a, E22b, E31a, E31
The data shown by b, E32a, and E32b are obtained. That is, of these data E11a to E32b, the data Enma corresponds to the vertical line x1 in (a) of FIG.
The data Enmb corresponds to the vertical line x2 in FIG. Further, these data E11a to E32b are calculated using the following equation (d), and the difference between the center lines of the respective images is taken as the amount of registration x1, x2, x3. Further, when these are averaged, the same result as that obtained by using the center of gravity in FIG. 4 is obtained.

[Equation 1] Enm = (Enma + Enmb) / 2 (d)

In addition, in printing unevenness of the laser printer,
When dots are printed, the distances may differ from x1 to xn even in the same line, as shown in FIG. 6, in which the central portion 39a is narrow and both end portions 39b are wide. In such cases,
If the center of gravity and the end position are known, the correction amount is
It can be calculated by the difference between a and both ends 39b.

In the correction described above, the image processing microprocessor 34 performs only the above-described binarization of the image data and the calculation of the area, circumference, center of gravity, and end region value of the image after binarization. In addition, all processing such as data transfer with a printer and processing of data calculated by the image processing microprocessor 34 is performed by the microcomputer 33.
It is something that is done in-house.

FIG. 7 shows a second embodiment of the system configuration to which the present invention is applied. In FIG. 7, the same reference numerals as those in FIG. 1 denote the same parts as those in FIG.
Further, in the second embodiment, the registration is corrected by the same procedure as in the flowchart shown in FIG. 2, and the system configuration of the second embodiment and the first embodiment shown in FIG. The major difference from the system configuration of the second embodiment is that the microcomputer 33 is used in the case of the system configuration of the first embodiment shown in FIG. 1, whereas the system configuration of the second embodiment is used. In the case of, the difference is that a microcomputer is not used.

In the system of the second embodiment, the printer 31, the microprocessor 41 connected to the printer 31 through the Centronics connector 43 as an interface and the Centronics cable 32, the image processing microprocessor 34, and the printing are connected. Pattern memory 42, video input processor 44, image data memory 45, CCD (solid-state image sensor) camera 3
It is composed of 6 etc. Further, among them, the microprocessor 41, the image processing microprocessor 34, the print pattern memory 42, the video input processor 44, and the image data memory 45 are compactly stored in one check box 46.

Next, the procedure for correcting the print misregistration in the system configuration of the second embodiment will be described. First, the microprocessor 41 sends the registration check print pattern data stored in the print pattern memory 42 to the printer 31 through the Centronics connector 43 and the Centronics cable 32, and prints the print sheet 3
The print pattern 40 is printed on the surface 7. Further, this print is read by the CCD camera 36, this data is converted into image data through the video input processor 44, and stored in the image data memory 45. Then, the image processing microprocessor 34 operates the stored image data in the same manner as described in the first embodiment to calculate the data of the area, perimeter, center of gravity, and end position for each image. Further, the microprocessor 41 determines the registration correction amount from the result, and the Centronics connector 43
And the printer 3 through the Centronics cable 32
1 and stores it in the memory (ROM) of a microprocessor (not shown) in the printer 31. Then, based on this data, the alignment adjustment mechanism (not shown) in the printer 31 is controlled to correct the print deviation. Therefore,
By performing the processing in this way, correction can be performed without requiring manpower even in the case of the present embodiment.

Incidentally, in the case of the second embodiment, it is possible to put other various check print patterns in the print pattern memory 42 and perform other tests at the same time. Can also be improved.

FIG. 8 shows an example of the inspection line equipment suitable for automatically performing the correction work in the system configuration to which the present invention is applied. 8 that are the same as those in FIG. 7 are the same as those in FIG. In this inspection line facility, a conveyor 51 for sending the printer 31 to be tested to the measurement position is provided, and the printer 31 is placed on the conveyor 51 and sent to the measurement position. On the other hand, at the measurement position, an arm 53 having a pressure sensitive sensor 52 is rotatably provided in the direction of arrow I-H in the figure, and a Centronics connector 43 coupled to the printer 31 side is provided with a slider 54. It is arranged so as to be slidable in the direction of the arrow F-G in FIG.

Next, this operation will be described. First, when the printer 31 is placed on the conveyor 51 and sent in the direction of arrow 55 in FIG. 8, the arm 53 is arranged so as to project in the direction of arrow F in FIG. It is in a state of crossing the passage. Therefore, in this state, when the printer 31 is sent to the measurement position, it collides with the arm 53, and when pressure is applied to the pressure sensor 52, the conveyor 51 stops.

When the printer 31 is positioned at the measurement position in this way, the slider 54 is then slid together with the Centronics connector 43 in the direction of arrow F in FIG.
Combined with 1. Then, the same system configuration as described with reference to FIG. 7 is formed, and the same registration correction is performed.

Further, when the correction process is completed, the slider 54 moves in the direction of arrow G in FIG.
This Centronics connector 4 slid along with 3
3 is removed from the printer 31, and the arm 53 is rotated in the direction of arrow I in FIG. Then, the conveyor 51 is operated again to send out the printer 31 for which correction has been completed, and the arm 5
3 is rotated in the direction of arrow H in FIG.
Waits for it to be sent, and when it is sent, the same operation is repeated again. In this embodiment, the printer 31
A cushion material 56 such as a sponge is attached to the arm 53 so as not to scratch the outer wall of the arm 53.

[0035]

As described above, according to the printer misregistration correction method of the present invention, the alignment of the impact printer can be corrected automatically and accurately, so that the correction does not require manpower. In addition, reproducibility can be obtained and adjustment can be performed in a short time. Further, it is possible to expect an effect that the lateral printing deviation of the non-impact laser printer can be corrected in exactly the same manner.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a print misregistration correction processing procedure of the present invention.

FIG. 3 is an explanatory diagram of binarization processing.

FIG. 4 is a diagram for explaining a method of calculating a registration correction amount using the position of the center of gravity of the calculation result calculated by the image processing microprocessor.

FIG. 5 is a diagram for explaining a method of calculating a registration correction amount using the end position of the calculation result calculated by the image processing microprocessor.

FIG. 6 is a diagram for explaining a state of print unevenness in the laser printer.

FIG. 7 is a system configuration diagram showing a second embodiment of the present invention.

FIG. 8 is a configuration diagram showing an example of an inspection line facility suitable for automatically performing the correction work in the present invention.

FIG. 9 is an external view showing an example of a conventional serial dot printer.

FIG. 10 is a configuration layout diagram schematically showing an internal structure of a conventional serial dot printer of the above.

FIG. 11 is a perspective view showing a structure that supports a print head and a space motor in the conventional serial dot printer.

FIG. 12 is a diagram showing in further detail the configuration of the peripheral portion of the space motor in the conventional same serial dot printer.

13 is a diagram showing the space motor shown in FIG. 12 as viewed from below.

FIG. 14 is a schematic configuration perspective view showing an example of a detection mechanism.

15 is a waveform chart showing an example of a sensor output of a photo sensor in the detection mechanism shown in FIG.

FIG. 16 is an external view of the printer in which a printed printing sheet is mounted.

FIG. 17 is a diagram for explaining the relationship between print misregistration and a printer.

FIG. 18 is an enlarged view showing a portion printed on a printing paper sheet with a print shift.

FIG. 19 is a diagram showing displacement-time characteristics in the movable portion of the space motor.

FIG. 20 is a configuration layout diagram schematically showing an example of a conventional printer system.

[Explanation of symbols]

31 Printer 32 Centronics Cable 33 Microcomputer 34 Image Processing Microprocessor 35 Memory 36 CCD Camera 37 Printing Paper

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Ishikawa 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. A printer having an alignment adjusting mechanism for correcting print misalignment, wherein a check print pattern is printed on the printer, and this print is read as image data by a camera,
A means for calculating a deviation amount to determine a correction amount, transmitting the correction amount as correction data to the printer, and a means for storing the correction data transmitted to the printer side in the printer. A printer misregistration correction method, comprising: controlling the alignment adjusting mechanism with the correction data stored in the printer to correct the printer misregistration.