JP2023063969A - recording device - Google Patents

Abstract

To provide a recording device which can achieve high-level image recording precision by securely correcting a mechanical precision error without using an expensive component or the like.SOLUTION: A recording device includes a table on which a recorded medium is placed, a recording head which discharges a recording agent to the recorded medium, movement means which relatively moves the table and the recording head to record on the recorded medium according to image data, control means which commands the movement means to relatively move the table and the recording head by a predetermined movement amount, acquisition means which acquires information relating to an error between the predetermined movement amount and an actual movement amount by the control means in movement by the moving means, and correction means which corrects image data according to the information relating to the error acquired by the acquisition means. The correction means divides the image data into a plurality of blocks respectively corresponding to a plurality of respective positions of the table, and corrects the image data by moving each of the plurality of blocks according to the information relating to the error.SELECTED DRAWING: Figure 15

Description

The present invention relates to a recording apparatus for recording an image on a recording medium.

Conventionally, as an image recording apparatus for directly recording an image on a recording medium, ink is applied to the recording medium while scanning an inkjet head having a nozzle row in which a plurality of nozzles for ejecting ink are arranged in a predetermined direction. 2. Description of the Related Art Ink jet recording apparatuses that record images by ejecting ink are known.

Inkjet recording devices are not only used for image recording of printed matter for visual inspection purposes such as photographic images, but may also be used for applying special inks such as functional materials. In some cases, a higher image recording accuracy than before is required to ensure that the ink droplets land on the intended position on the surface of the recording medium. 2. Description of the Related Art In recent years, various techniques have been proposed for improving recording accuracy of image recording by an inkjet recording apparatus.

JP 2010-204421 A Japanese Patent Application Laid-Open No. 2021-21782

For example, in Patent Document 1, in a drawing apparatus for a substrate, drawing data for drawing a circuit pattern converted from vector data to raster data is divided into a plurality of mesh regions, and the mesh regions are arranged at the positions of alignment marks provided on the substrate. By rearranging the mesh area according to the shape of the substrate based on the lithography method, it is possible to easily generate drawing data corresponding to deformation such as warping and distortion of the substrate and distortion due to processing in the previous process. is proposed.

Further, in Patent Document 2, in a drawing apparatus for a substrate, run-length data of an image corresponding to a plurality of segmented tilt angles, which are deviations in the circumferential direction of the substrate from a reference position on a stage, are used as a plurality of initial drawing data. One of the initial drawing data is stored in advance according to the actual tilt angle of the substrate on the stage, and a plurality of drawing blocks arranged in a matrix are set for the selected initial drawing data. By moving the drawing block according to the difference between the tilt angle and the section tilt angle, the drawing data is generated quickly, and the substrate placed at an angle on the stage is drawn quickly and accurately. A rendering device has been proposed.

By the way, an inkjet recording apparatus is composed of various members such as an inkjet head, a table on which a recording medium is placed, a carriage on which the inkjet head and the like are mounted, and various drive units for driving the carriage and the table. Therefore, the ink ejected from the inkjet head may be caused by machine accuracy errors based on complex factors including but not limited to poor manufacturing accuracy of the members that make up the inkjet recording apparatus, and poor assembly accuracy of each member. Degradation of recording quality may occur due to the occurrence of poor landing accuracy in which the droplets do not land on the intended position of the image data on the surface of the recording medium.

Resolving such machine accuracy errors by selecting high-precision components or improving assembly accuracy will lead to an increase in part prices and an increase in the number of assembly man-hours, which will lead to an increase in the manufacturing cost of the inkjet recording device. Connect. In addition, as described above, in the inkjet recording apparatus, depending on the application, higher image recording accuracy is required than in the past, and these methods may not be able to satisfy the required image recording accuracy.

Furthermore, the above machine accuracy error occurs as a defect in the image recording accuracy of the ink jet recording apparatus itself regardless of the distortion of the recording medium and the mounting state. In some cases, errors in the shape of the recording medium itself, such as warpage, cannot be resolved by correcting the drawing data according to the inclination of the mounting on the stage. Machine accuracy errors are disclosed in these documents. It can also cause a decrease in the accuracy of recording using drawing data generated by the method.

The present invention has been made in view of the above problems, and can solve the above problems, reliably correct machine accuracy errors without using expensive parts, etc., and realize high image recording accuracy. It provides a recording device that

In order to achieve the above object, the inventor of the present invention discovered the following configuration as a result of diligent ingenuity.

That is, in the present invention,
a table on which a recording medium is placed;
a recording head that ejects a recording agent onto the recording medium placed on the table;
moving means for relatively moving the table and the recording head in order to perform recording on the recording medium according to image data;
a control means for instructing the moving means to move the table and the recording head relative to each other according to a predetermined amount of movement;
an error between the predetermined movement amount commanded by the control means for the movement means and the actual relative movement amount between the table and the recording head by the movement means according to the command by the control means; Acquisition means for acquiring information related to
a first correcting means for correcting the image data according to the information about the error acquired by the acquiring means;
has
The first correction means divides the image data into a plurality of blocks each corresponding to each of the plurality of positions of the table, and divides each of the plurality of blocks into a relative position of the corresponding recording head. The recording apparatus is characterized in that the image data is corrected by moving according to the errors of each of the plurality of positions.

Further, the moving means includes means for relatively moving the table and the recording head in a first direction, and a second moving means for moving the table and the recording head in a direction substantially orthogonal to the first direction. and means for relatively moving in a direction, wherein the information regarding the error includes information regarding the error in the first direction and the second direction.

Also, the first correcting means is characterized by comprising storage means for storing information relating to the error.

Further, the storage means stores a plurality of information relating to the error for each temperature of the recording device, and the first correction means selects the recording device from the plurality of information relating to the error stored in the storage means. is selected, and the block is moved according to the selected error information.

Further, by using two or more pieces of information related to the temperature-specific error stored in the storage means, the information related to the error corresponding to the temperature not stored in the storage means is further calculated. do.

Further, in the first correcting means, when an area where pixels overlap between adjacent blocks occurs when the block is moved, the image data of the overlapping area is subjected to a logical addition process. and

Further, in the first correcting means, the block is further divided when the amount of movement of the block exceeds a predetermined first specified amount.

Further, it is characterized in that the first specified amount is one pixel.

The image forming apparatus further comprises shape information acquisition means for acquiring shape information relating to the shape of the recording medium, and second correction means for correcting the image data according to the shape information.

The recording medium has a recording area in which the image data is recorded, and a plurality of alignment marks arranged in an outer peripheral area of the recording area in a predetermined positional relationship with respect to the recording area,
The shape information acquiring means acquires the shape information based on position information of the plurality of alignment marks on the recording medium placed on the table.

The second correcting means divides the image data into a plurality of blocks and corrects the image data by moving the plurality of blocks according to the shape information.

Further, the size of the block divided by the first correcting means is equal to the size of the block divided by the second correcting means, and the first correcting means and the second correcting means Boundaries of the divided blocks are different from each other.

Further, in the first correcting means or the second correcting means, when an area where pixels overlap between adjacent blocks occurs when the blocks are moved, the image data of the overlapping area is corrected. It is characterized by performing logical sum processing.

Further, in the second correction means, the block is further divided when the amount of movement of the block exceeds a predetermined second specified amount.

Further, it is characterized in that the specified amount is one pixel.

Furthermore, a table on which the recording medium is placed;
a recording head that ejects a recording agent onto the recording medium placed on the table;
moving means for relatively moving the table and the recording head in order to perform recording on the recording medium according to image data;
a control means for instructing the moving means to move the table and the recording head relative to each other according to a predetermined amount of movement;
an error between the predetermined movement amount commanded by the control means for the movement means and the actual relative movement amount between the table and the recording head by the movement means according to the command by the control means; a storage means for storing information relating to
shape information acquisition means for acquiring shape information relating to the shape of the recording medium;
correction means for dividing the image data into a plurality of blocks each corresponding to each of the plurality of positions of the table, and correcting the image data by moving each of the plurality of blocks;
has
The correction means causes each of the plurality of blocks to move by a movement amount according to the information related to the error stored in the storage means and the shape information acquired by the shape acquisition means. It can also be configured with a recording apparatus characterized by:

Further, the moving means includes means for relatively moving the table and the recording head in a first direction, and a second moving means for moving the table and the recording head in a direction substantially orthogonal to the first direction. and means for relatively moving in a direction, wherein the information includes information regarding errors in the first direction and the second direction.

Further, the storage means stores a plurality of information relating to the error for each temperature of the recording device, and the correction means determines the temperature of the recording device from the plurality of information relating to the error stored in the storage means. The error information is selected according to the error, and the block is moved according to the selected error information.

Further, by using two or more pieces of information related to the temperature-specific error stored in the storage means, the information related to the error corresponding to the temperature not stored in the storage means is further calculated. do.

The recording medium has a recording area in which the image data is recorded, and a plurality of alignment marks arranged in an outer peripheral area of the recording area in a predetermined positional relationship with respect to the recording area. ,
The shape information acquiring means acquires the shape information based on position information of the plurality of alignment marks on the recording medium placed on the table.

Further, in the correcting means, when an area where pixels overlap with the adjacent blocks occurs when the blocks are moved, the image data of the overlapping area is subjected to logical sum processing.

Further, in the correcting means, when the amount of movement of the block exceeds a predetermined amount, the block is further divided.

Further, it is characterized in that the specified amount is one pixel.

According to the present invention, with the configuration described above, it is possible to solve the above problems and provide a recording apparatus that is inexpensive and achieves a high degree of image recording accuracy.

1 is a schematic diagram showing a configuration example of an inkjet recording apparatus; FIG. FIG. 4 is a schematic diagram showing an ideal movement trajectory of the table in the Y direction and an example of an actual movement trajectory; FIG. 10 is a schematic diagram showing an example of a phenomenon that occurs when scaling is performed; It is a schematic diagram explaining an example of a block correction process. FIG. 10 is a schematic diagram showing an example in which image data of a checkered pattern is moved by one pixel from upstream to downstream in the X direction for enlargement; FIG. 6 is a schematic diagram showing how ink dots are formed before and after enlargement in an enlarged portion when the image of FIG. 5 is printed; FIG. 10 is a schematic diagram showing an example in which image data of a checkered pattern is shifted by one pixel from downstream to upstream in the X direction for reduction; 8 is a schematic diagram showing how ink dots are formed before and after enlargement in an enlarged portion when the image of FIG. 7 is printed; FIG. It is a schematic diagram which shows an example of a glass scale. It is a schematic diagram which showed the reading condition of the glass scale using the camera. FIG. 10 is a schematic diagram showing an overall image of a state of occurrence of a deviation between linear encoder coordinates and a reference mark on a table plane. FIG. 10 is a table listing a part of linear encoder coordinates at reference position coordinates in a predetermined row in the X direction and calculated correction values obtained by measuring a glass scale with a camera; FIG. FIG. 10 is a schematic diagram showing a modified example of image data according to correction values; FIG. 10 is a conceptual diagram illustrating an aspect of arranging virtual blocks in a table to perform block correction processing and an example of a situation in which in-table block correction data is created; It is a flow chart explaining a first embodiment. FIG. 4 is a conceptual diagram illustrating switching of block correction data in a table and block correction processing according to temperature conditions of an inkjet printing apparatus; It is a schematic diagram which shows an example of the printed wiring board of a to-be-recorded medium. FIG. 4 is a schematic diagram showing how alignment marks on a printed wiring board are read using a camera; FIG. 4 is a schematic diagram illustrating a situation of converting a quadrangle having four vertices of alignment marks in image data into a quadrangle having four vertices of alignment marks of a printed wiring board as a recording medium; FIG. 10 is a table in which the numbers of moving pixels calculated as a result of the above calculation are arranged for each block according to the arrangement of the blocks; FIG. It is a chart figure explaining the whole picture of the first example in a second embodiment. FIG. 10 is a schematic diagram showing a state in which predetermined phases are set after unifying block sizes in the first block correction process and the second block correction process; FIG. 10 is a schematic diagram showing a situation in which a block that needs to move more than 1 pixel is further divided so that one block does not move more than 1 pixel; It is a flow chart which shows the flow of the first example in the second embodiment. It is a chart figure explaining the whole picture of the second example in a second embodiment. FIG. 11 is a flow chart showing the flow of a second example in the second embodiment; FIG.

A first embodiment according to the present invention will be described below with reference to FIGS. 1 to 16. FIG.

FIG. 1 is a schematic diagram showing a configuration example of an inkjet recording apparatus used in this embodiment.

The carriage 2 has an inkjet head 1 having a nozzle surface in which a plurality of nozzles are arranged in the nozzle row direction, a control board 3 for controlling the inkjet head 1, a sub-tank 4 for supplying ink to the inkjet head 1, a camera 5 for imaging a recording medium 7, and the like. , camera lighting 6, etc. are mounted, and are moved in the left-right direction (X direction) on the paper surface by being driven by the X-axis drive unit 8. FIG.

A predetermined amount of ink is supplied to the sub-tank 4 to be supplied to the inkjet head 1 below. By activating the pump 11 in response to a signal from a liquid level sensor (not shown) and supplying ink from the main tank 10 to the sub-tank 4, the liquid level of the ink in the sub-tank 4 is kept substantially constant so that the amount of ink in the sub-tank 4 reaches a set level. are doing.

Further, the gas portion in the sub-tank 4 is controlled to have a negative pressure by a negative pressure pump 9 so that the ink can stably be discharged from the nozzles of the inkjet head 1 without leaking. By feeding back the measured value of the negative pressure sensor (not shown) to the negative pressure pump 9, a constant negative pressure value is always applied to the gas portion in the sub-tank. Also, by switching the three-way valve 17 and applying a gas of 1 atm or more from the positive pressure pump 18 into the sub-tank 4 to create a positive pressure, the ink can be forcibly discharged.

The control personal computer 12 is connected to the control board 3 mounted on the carriage 2 via an interface board 13, and print data and printing conditions can be set from the control personal computer 12. FIG. The control personal computer 12 is also equipped with storage means 51 such as a memory capable of storing various types of necessary information such as block correction data in a table, which will be described later. In addition, the control personal computer 12 has a selection means 55 realized by the operation of the CPU, etc., and can select appropriate one from a plurality of in-table block correction data stored in the storage means 51, for example. .

The recording medium 7 is attracted to the table 14 with a predetermined distance (preferably about 1 mm to 3 mm, but not limited to this) between the nozzle surface of the inkjet head 1 and the surface of the recording medium 7 . is placed on the By driving the Y-axis drive unit 15, the table 14 can be moved in the front and back direction (Y direction) of the plane of FIG. 1, which is a direction substantially perpendicular to the X direction. A gate-type frame (not shown) for supporting the X-axis drive unit 8, the Y-axis drive unit 15, and the like are all fixed on a base plate 16 that is sturdy and has high plane accuracy.

By driving the X-axis drive unit 8, the inkjet head 1 is moved by a predetermined distance in the X direction. With the position of the inkjet head 1 in the X direction fixed, by driving the Y-axis drive unit 15, the table 14 is moved in the Y direction. Printing is performed by ejecting ink onto the recording medium 7 from the nozzles of the inkjet head 1 while moving the ink jet head 1 . Further, the X-axis drive unit 8 is driven to move the inkjet head 1 in the X direction by a predetermined distance. Further printing is performed by ejecting ink from the nozzles of the inkjet head 1 onto the recording medium 7 while moving the recording medium 1 to .
By alternately repeating the movement of the inkjet head 1 in the X direction and the movement of the table 14 in the Y direction, the surface of the recording medium 7 placed over the entire surface of the table 14 is Printing can be performed on the entire surface in the X direction and the Y direction.

The X-axis drive unit 8 and the Y-axis drive unit 15 employ drive means capable of linear motion such as linear motors and ball screws. Applies. In this embodiment, various types of position detection means can be applied, and for example, a linear encoder can be used.

A linear encoder is a device that detects a position in a linear direction and outputs it as position information, and is also called a linear encoder, a positioning encoder, or a linear scale. A linear encoder is usually composed of a scale (division) that serves as a ruler and a head (detector) that detects position information. In addition, there are two types of linear encoders: the optical type that uses light reflection to detect the scale, and the magnetic type that uses magnetism. There is an increment expression. In the present embodiment, whether or not the position detection means is a linear encoder, and even if a linear encoder is applied, whether it is optical, magnetic, or other means, and whether it is an absolute type or an incremental type , and other means are not limited, and appropriate methods can be adopted.

The temperature sensor 19 can measure the temperature inside the ink jet recording apparatus and transfer the measured temperature data to the control personal computer 12 via a cable (not shown). In the inkjet recording apparatus illustrated in FIG. 1, an example in which one temperature sensor 19 is arranged is shown, but a plurality of temperature sensors 19 may be installed to measure temperatures at a plurality of locations.

FIG. 2 is a schematic diagram showing an ideal movement trajectory of the table 14 in the Y direction and an example of an actual movement trajectory. As described above, the table 14 is driven by the Y-axis drive unit 15 to move in the Y direction. Here, in order to print the ink droplets on the surface of the recording medium 7 with high landing accuracy, the table 14 should originally move on the ideal straight line indicated by the dotted line 20 . However, in reality, the movement of the table 14 is affected by errors in machine accuracy, and a poor movement accuracy may occur in which the table 14 moves along a meandering movement track as indicated by the thick line 21, for example. In the example of FIG. 2, the table 14 follows the movement trajectory of the thick line 21 and slightly tilts as it moves from upstream to downstream in the Y direction from position 22, position 23, and position 24. In FIG.

Poor movement accuracy due to such machine accuracy errors may occur under the influence of manufacturing accuracy, assembly accuracy, and the like of each component that constitutes the inkjet recording apparatus. For example, the accuracy of assembling the table 14 and the Y-axis driving unit 15, the linear motion accuracy of the Y-axis driving unit 15 itself, the assembling accuracy of the Y-axis driving unit 15 and the base plate 16, etc. can be expected. Furthermore, the movement instructed by the control personal computer 12 caused by the influence of the error in the absolute position accuracy of the linear encoder itself constituting the Y-axis drive unit 15 and the accuracy of attaching the linear encoder to the Y-axis drive unit 15 The influence of the error between the amount and the amount of movement of the Y-axis drive unit 15 is also assumed.

Poor movement accuracy due to such mechanical accuracy errors can naturally occur when the inkjet head 1 is moved in the X direction by driving the X-axis drive unit 8 . For example, the assembly accuracy of the inkjet head 1, the carriage 2, and the X-axis drive unit 8, the linear motion accuracy of the X-axis drive unit 8 itself, and the assembly accuracy, etc., may have an effect. Furthermore, the movement instructed by the control personal computer 12 is caused by the error in the absolute position accuracy of the linear encoder itself constituting the X-axis drive unit 8 and the accuracy of pasting the linear encoder to the X-axis drive unit 8. The influence of the error between the amount and the amount of movement of the Y-axis drive unit 15 is also assumed.

Due to poor movement accuracy due to such mechanical accuracy errors, ink droplets ejected from the inkjet head 1 do not land on the intended position on the surface of the recording medium 7, resulting in poor landing accuracy and deterioration in recording quality. However, depending on the means of improving the machine accuracy itself, such as selecting higher-precision parts to improve the machine accuracy error and improving the accuracy to improve the assembly accuracy, the price of parts and the number of assembly man-hours may increase. lead to an increase.

Therefore, in the first embodiment, information about the relative positional deviation between the inkjet head 1 and the table 14 is acquired, and image data used for image recording is transferred to a block described later according to the acquired information. By performing correction processing and deforming, the ink landing position is adjusted according to the state of poor movement accuracy due to mechanical accuracy error, thereby improving the deterioration of the recording quality. The correction processing in the first embodiment will be described in detail below.

First, as a premise for the description of the first embodiment, block correction processing including block division and block movement of image data will be described.

As a premise, the purpose of using block correction processing will be described. When the method of simply transforming the print image data is used to correct the machine precision error, one pixel line disappears due to the scaling of the print image data due to the nature of the image processing. A phenomenon may occur in which one pixel line becomes two pixel lines due to enlargement. FIG. 3 is a schematic diagram showing an example of a phenomenon that occurs when scaling is performed. As shown in FIG. 3, a phenomenon that one pixel line disappears due to reduction and a phenomenon that one pixel line becomes two pixel lines due to enlargement may occur. These phenomena do not necessarily occur during enlargement/reduction, but may occur with a certain probability depending on the enlargement/reduction magnification. For example, if the image data of 1000×1000 pixels is reduced to 99%, it is necessary to delete 1 pixel out of 100 pixels, or 10 pixels in total. may occur. In addition, when the image is enlarged to 101%, it is necessary to increase the image by 1 pixel per 100 pixels, or a total of 10 pixels. possibility to occur. Occurrence of such a phenomenon causes a phenomenon in which printing is not performed on a portion that should be printed or a phenomenon in which printing is performed on a position that should not be printed. Therefore, by adopting a method of dividing the print image data into blocks and moving the blocks according to the machine precision error, the above-mentioned problems associated with scaling of the print image data can be avoided and image deformation can be realized.

FIG. 4 is a schematic diagram illustrating an example of block correction processing. In FIG. 4, for convenience of explanation, the image data 44 of 100×100 pixels is divided into four blocks 47 of 50×50 pixels, and the lower right block 47 (most downstream in the X and Y directions) is A simplified example of moving is used. Each block 47 is designated with a representative point 76 as the reference origin of the block 47 . One representative point may be designated at a predetermined position such as the upper left, center, lower left, or other position of each block 47, but in this example, the upper left of each block 47 ). Each block 47 is moved by setting the amount of movement of the representative point 76 of each block 47 and moving the entire block 47 according to the movement of each representative point 76 .

FIG. 4(a) shows a state before execution of block correction processing, in which four blocks are arranged adjacently without movement. In FIG. 4B, the lower right block 47 is moved by one pixel in the downstream expansion direction in the X direction. As a result, image data transformation equivalent to transformation of the image data as a whole into image data of 101×100 pixels is realized. In FIG. 4C, the lower right block 47 is moved by one pixel in the downstream enlargement direction in the X direction and by one pixel in the upstream reduction direction in the Y direction. As a result, the image data as a whole is transformed into image data of 101.times.100 pixels as in FIG. 4B. Considering the upper left block 47 as a reference, the upper right, lower left, and lower right blocks 47 can be moved up, down, left, and right by one pixel.

Here, in performing the block correction processing in this embodiment, by keeping the amount of movement of each block 47 within one pixel, it is possible to avoid the deterioration of the printing image quality caused by the block correction processing. This point will be described below.

First, in the block correction process, when the block 47 is moved in the one-pixel enlargement direction, the interval between the block 47 and the adjacent block 47 is increased by one pixel.

FIG. 5 is a schematic diagram showing an example in which image data of a checkered pattern is shifted by one pixel from upstream to downstream in the X direction for enlargement. In this example, by moving one pixel from upstream to downstream in the X direction, the length in the horizontal direction (X direction) is increased from 16 pixels to 17 pixels.

FIG. 6 is a schematic diagram showing how ink dots are formed before and after enlargement in an enlarged portion when the image of FIG. 5 is printed. Note that FIG. 6 uses an example in which the resolution of the image data is 2880 dpi. When the ink dot 48 and the ink dot 49 move one pixel relative to each other in the enlargement direction, if the image data is 2880 dpi, the interval between one pixel of the image data is about 8.8 μm, which is equivalent to one pixel in the enlargement direction. When moved, the interval doubles to 17.6 μm. At this time, the ink droplet size of one pixel after printing spreads on the recording medium, and each of the ink dots 48 and 49 has a diameter of about 50 μm. Therefore, even if the ink dots 48 and 49 are moved by 8.8 μm in the enlargement direction as a result of moving the adjacent pixels of the image data by one pixel, the ink dots 48 and 49 will still overlap. , and no white streaks are generated.

Further, when the block 47 is moved in the one-pixel contraction direction, the block 47 and the adjacent block 47 overlap by one pixel.

FIG. 7 is a schematic diagram showing an example in which image data of a checkerboard pattern is shifted by one pixel from downstream to upstream in the X direction for reduction. In this example, by moving one pixel from downstream to upstream in the X direction, the length in the horizontal direction (X direction) is reduced from 16 pixels to 15 pixels. By moving in the direction of reduction, the lines of the reduced portion overlap. When the image data is a checkerboard pattern as in this example, the image data of the overlapped portion is logically sum-processed, resulting in a solid image with a density of 100%.

FIG. 8 is a schematic diagram showing how ink dots are formed before and after enlargement in an enlarged portion when the image of FIG. 7 is printed. Note that FIG. 8 also uses an example in which the resolution of image data is 2880 dpi. As described above, if the image data is 2880 dpi, the interval of one pixel of the image data is about 8.8 μm. When moved by one pixel in the reduction direction, the interval becomes about 0 μm. After printing, the ink droplet size of one pixel spreads on the recording medium and has a diameter of about 50 μm. In this way, the ink dots 48 and 49 are still overlapping each other before and after reduction, and the recording quality as a whole is hardly affected, and phenomena such as black streaks do not occur.

In this way, in the block correction process, by keeping the amount of movement of the block 47 within one pixel, it is possible to avoid deterioration of print quality due to block correction. Various methods are conceivable for keeping the amount of movement of the block 47 within one pixel. is further reduced, the amount of movement of each block 47 can be kept within one pixel. Further, by minimizing the number of blocks 47 that need to be moved and minimizing the overall amount of movement of the blocks 47, the amount of movement of the blocks 47 can be reduced from the viewpoint of improving the processing speed. It can also be the maximum size within one pixel.

Another method for keeping the amount of movement of the block 47 within one pixel in the block correction process will also be described. FIG. 23 is a schematic diagram showing a situation in which a block requiring movement of more than one pixel is further divided so that one block does not move more than one pixel. In the example of FIG. 23, when there is a block 47 whose movement amount exceeds one pixel, only the block 47 whose movement amount exceeds one pixel is further divided, and each divided block 47 is moved one pixel at a time. I am letting This method can also keep the amount of movement of the block 47 within one pixel.

The above is the outline of the block correction processing that is the premise of the first embodiment.

Next, a method of acquiring information regarding relative positional deviation between the table 14 and the inkjet head 1 when the table 14 and the inkjet head 1 move relative to each other in the X direction and the Y direction will be described.

In the inkjet recording apparatus shown in FIG. 1, linear motors and ball screws can be used as drive units for the X-axis drive unit 8 and Y-axis drive unit 15, as described above, and linear encoders can be used as position detection means. The linear encoder detects the position in the linear direction and outputs it as position information. However, as explained with reference to FIG. 2, the relative positional accuracy required for the table 14 and the inkjet head 1 can be achieved due to problems such as non-linear movement of the table 14 and mechanical accuracy errors such as mounting accuracy of the linear encoder. Sometimes you can't. As for the relative position between the table 14 and the inkjet head 1, the position information output from the linear encoder may differ from the actual position due to machine precision errors.

In this way, in the inkjet recording apparatus, machine accuracy errors can occur due to the influence of the manufacturing accuracy and assembly accuracy of each part that constitutes the inkjet recording apparatus. As a premise for this, it is necessary to acquire information regarding the relative positional deviation between the actual table 14 and the inkjet head 1 . Therefore, a method of acquiring information related to relative positional deviation will be described below.

Various reference position information generating means are applied to obtain information related to the relative positional deviation between the table 14 and the inkjet head 1 . Based on the difference between the reference position coordinates, which are reference position information generated by the reference position information generating means, and the linear encoder coordinates, which are position information obtained from the linear encoders of the X-axis drive unit 8 and the Y-axis drive unit 15 , to obtain information about the relative positional deviation.

Means capable of measuring a reference position on a plane in the X direction and the Y direction is applied as the reference position information generating means. For example, a laser length measuring machine, various plane scales, and the like can be applied, but a means that causes little change in shape due to temperature change, physical impact, or the like is preferable. A glass scale with a small coefficient of thermal expansion and a small accuracy error due to ambient temperature is assumed as one of the reference position information generating means having a feature that the shape change due to temperature change, physical impact, etc. is small.

In the case of using a laser length measuring machine, for example, position information in the X direction obtained from a linear encoder for a plurality of points in the Y direction on the carriage 2 is based on the position information obtained from the laser length measuring machine. Then, compare the position information of each of the multiple points obtained using the laser length measuring machine to confirm the deviation between the true position information obtained from the laser length measuring machine and the position information obtained from the linear encoder, Further, for a plurality of points in the X direction on the table 14, the position information in the Y direction obtained from the linear encoder is compared with the position information of each of the plurality of points obtained using the laser length measuring machine, and the By confirming the deviation between the true positional information acquired and the positional information acquired from the linear encoder, it is possible to acquire information about the relative positional deviation in the X direction and the Y direction.

In this embodiment, a glass scale is used as the reference position measuring means. Further, as shown in FIG. 1, the camera 5 is mounted on the carriage 2 on which the inkjet head 1 is mounted in a predetermined positional relationship with respect to the inkjet head 1, and the inkjet head 1 is positioned at the camera 5 position. requested accordingly. Further, the positional information of the table 14 is obtained based on the reference marks of the glass scale placed on the table 14 .

FIG. 9 is a schematic diagram showing an example of a glass scale. Reference marks 26 having a diameter of 0.5 mm are arranged on the outer surface of the glass scale 25 at intervals of 10 mm. The accuracy of the glass scale used in this example is preferably about +-1 μm. A plurality of reference marks 26 are arranged in the X direction and the Y direction with an accuracy of 10 mm+−1 μm. In the example of the glass scale 25 shown in FIG. 9, eight reference marks 26 are arranged in the X direction and eight reference marks 26 are arranged in the Y direction. Various sizes and accuracies of the glass scale 25 can be applied depending on the application.

Then, the glass scale 25 is placed on the table 14 and the reference mark 26 of the glass scale 25 is read using the camera 5 . The reading of the fiducial marks will be described below.

FIG. 10 is a schematic diagram showing how a glass scale is read using a camera. FIG. 10(a) is a schematic diagram of an imaging frame of the camera 5. FIG. The outer camera frame 27 shows the entire field of view of the camera 5. For example, when the number of pixels is 1280 pixels×1024 pixels and the resolution per pixel is 5 μm, the field of view in the X direction is 1280 pixels×5 μm=6.4 mm. , the field of view in the Y direction is 1024 pixels×5 μm=5.12 mm. An intersection point 28 of dotted lines indicates the center of the camera frame 27 . By taking an image of the reference mark 26, which is the reference position, and measuring the amount of deviation between the reference mark 26 and the intersection 28, the ink jet head 1 mounted on the carriage 2 on which the camera 5 is mounted and the table 14 are measured. Acquire information related to the relative positional deviation of the .

FIG. 10(b) is an example of an imaging situation of the reference mark 26, showing how the reference mark 26 with a diameter of 0.5 mm is imaged at the intersection 28 which is the center of the camera frame 27. FIG. The fact that the reference mark 26 is imaged as shown in FIG. 10(b) means that the relative positions of the inkjet head 1 and the table 14 are different at the position of the reference mark 26 imaged in FIG. 10(b). This means that no deviation has occurred.

FIG. 10(c) is also an example of the imaging situation of the reference mark 26. In this example, the reference mark 26 of the glass scale is positioned in the X direction and the Y direction from the intersection 28 of the camera frame. It shows a state in which an image is captured with a shift amount corresponding to the coordinate correction value 32 . The fact that the image is taken as shown in FIG. 10C means that there is a relative positional deviation at the position of the reference mark 26 imaged in FIG. 10C, and correction is necessary. It shows that it becomes An X-coordinate correction value 31 and a Y-coordinate correction value 32 in the figure are acquired by the number of pixels because they are captured by a camera. When the resolution per pixel of the camera 5 is 5 μm as in the above example, the values of the X-coordinate correction value of 31×5 μm and the Y-coordinate correction value of 32×5 μm are the amounts of deviation. Even if the camera resolution is 5 μm/pixel, the reference position coordinates are measured at the center of gravity of the reference mark 26, as will be described later, so that they can be measured with a finer resolution than 5 μm.

An overall image of the occurrence of relative positional deviation obtained by imaging the reference mark 26 will be described. FIG. 11 is a schematic diagram showing an overall image of the state of deviation between the linear encoder coordinates and the reference mark on the table plane. FIG. 11A shows the reference marks 26 of the glass scale 25 illustrated in FIG. 9 and the linear encoder coordinates 52 corresponding to each of the reference marks 26 . Assuming that the reference marks 26 are arranged on the glass scale 25 at intervals of 10 mm, if the carriage 2 moves the X-axis drive unit 8 and the Y-axis drive unit 15 by 10 mm according to the position information obtained from the linear encoder, Originally, the linear encoder coordinates 52 and the reference position coordinates obtained from the reference mark 26 should match. However, due to machine accuracy errors caused by the above-described complex factors, actually, the linear encoder coordinates 52 and the reference position coordinates that originally correspond to them have different amounts of deviation depending on the location.

FIG. 11(b) is an enlarged view of a reference mark 26 and its corresponding linear encoder coordinates 52. FIG. The intersection of the dotted lines on the reference mark 26 indicates the center of the reference mark 26 and the reference position coordinates. The difference from the linear encoder coordinates 52 is the X coordinate correction value 31 and the Y coordinate correction value 32 described above.

Numerical examples of coordinate information acquired in the above process will be described. FIG. 12 is a list showing part of the linear encoder coordinates at the reference position coordinates in a predetermined row in the X direction and the calculated correction values obtained by measuring the glass scale with the camera. The unit of numerical values is μm. Linear encoder coordinates indicate position information obtained from a linear encoder. The reference position coordinates indicate reference position information obtained from the reference mark 26 of the glass scale 25. Based on the position information of the linear encoder, the camera 5 is moved in the X direction at intervals of 10 mm. 26 center value (center of gravity) measured by an alignment camera. Numerical values of adjacent blocks in the X direction are recorded for each row of the table in FIG.

The "linear encoder coordinates" column shown in the table of FIG. 12 is the X, Y coordinates based on the position information of the linear encoder moved in the X direction in 10 mm steps, and the "reference position coordinates" column is based on the image captured by the alignment camera. It is the X, Y coordinates based on the calculated positional information of the reference mark 26 of the glass scale 25 . When the glass scale 25 illustrated in FIG. 9 is used, there are 8×8 reference marks 26 in the X and Y directions. It will be captured as XY coordinates via. The difference between the position information of the linear encoder coordinates and the position information of the reference position coordinates is an example of the "relative positional deviation" to be corrected. column. For the linear encoder coordinates in the first row of the table in FIG. 12, the X-coordinate error is 6364-6423=-59 μm, and the Y-coordinate error is 47479-47471=8 μm. When it is necessary to print image data of 2880 dpi, the interval of one pixel is about 8.8 μm, and the X coordinate is 59/8.8=6.7 pixels. There will be Also, the Y coordinate is 8/8.8=0.9 pixels, and this position has a cumulative deviation of about 1 pixel. Also, as shown in the correction value 43, the difference between the XY coordinates of adjacent blocks is within one pixel.

In addition, in the inkjet recording apparatus to which the present embodiment is applied, a more remarkable effect is exhibited particularly in high-resolution printing. For example, an ink dot is further formed between each ink dot formed by performing a plurality of recording operations with the ink jet head 1 on a unit recording area on the surface of the recording medium 7 using an ink jet recording apparatus, and the nozzle interval is When multi-pass printing is performed to perform image recording that complements the above, a print resolution of 2400 dpi can be achieved if the resolution of the inkjet head 1 used is 600 dpi, and a print resolution of 2880 dpi can be achieved if the resolution of the inkjet head 1 used is 360 dpi. resolution can be achieved. Therefore, in the following description, a resolution of 2400 dpi or 2880 dpi will be described as an example.

Through the above-described process, the value of the position information of the reference position coordinates is set to be true with respect to the entire table 14 at intervals at which the reference marks 26 of the glass scale 25 are arranged, which is the premise of the block correction process. A correction value, which is a numerical value to be corrected according to a relative positional deviation due to an accuracy error, can be calculated. Based on the obtained correction value, block correction processing is performed on the entire image data to be printed, and the image data is deformed according to the relative positional deviation to correct the machine precision error.

First, an overview of block correction processing for machine precision errors will be described. FIG. 13 is a schematic diagram showing a modified example of image data according to correction values. A deformed image shape 45 indicates the outer shape of the converted print image data obtained by deforming the image data 44 in accordance with the machine precision of the apparatus, and the converted image data 46 is indicated by the outer dotted line. there is The inner block 47 shows the state after the movement, and it becomes a shape spread over the shape of the image after deformation, but a part of it is shown here. The image block is moved up, down, left, and right while maintaining the condition that the amount of movement between the image block and its neighbor is within a predetermined value, for example, within one pixel, and is converted into image data 46 that substantially matches the machine precision distortion as a whole.

Also, the machine precision error of the actual apparatus is reversed to the shape of the image data after deformation. For convenience of explanation, the image shape 45 after deformation is shown as a deformed shape as illustrated, but if the machine accuracy error is 100 μm or less for a length of 500 mm, the actual deformation will be slight. . Blank data is arranged between the image shape 45 after deformation and the image data 46 after conversion because they are not actually printed.

By processing in this way, it is possible to avoid the problem that one pixel line disappears due to reduction as described above, or that one pixel line becomes two pixel lines due to enlargement. Since the correction can be made different for each pixel, it is possible to correct non-linear distortion as shown in FIG.

14A and 14B are conceptual diagrams for explaining a mode in which virtual blocks are arranged in a table and block correction processing is performed, and an example of a situation in which in-table block correction data is created. In order to correct the machine precision error, virtual blocks are set on the table 14 as blocks 47 corresponding to the reference position coordinates of each of the reference marks 26, as indicated by dotted line grids in FIG. , the representative point 76 is set as described above, and the correction value obtained by the above method is applied to this representative point 76, and the entire virtual block including the representative point 76 is corrected according to the movement of the representative point 76. is moved by the correction value to perform the block correction process, thereby eliminating the above-described deviation between the linear encoder coordinates 52 and the reference position coordinates, and accuracy according to the position information of the linear encoder coordinates 52 acquired by the linear encoder A state equivalent to when the inkjet head 1 and the table 14 are relatively moved is often realized. For this reason, block correction data in the table is prepared in advance before printing, stored in the storage means 51 of the control personal computer 12, and referenced at the time of printing, thereby correcting machine accuracy errors in each printing operation. It is possible to print in

FIG. 14(a) shows how the entire table 14 is divided into virtual blocks, divided by dotted lines, and the virtual blocks are arranged. For example, the virtual blocks are arranged and set at intervals of 10 mm in the X and Y directions from the origin at the upper left of the table. 14(b) and 14(c) are tables showing the correction values for the respective blocks described above by enlarging the upper left portion of the table 14 in which the virtual blocks of FIG. 14(a) are arranged. The unit is μm. FIG. 14B shows correction values in the X direction, and FIG. 14C shows correction values in the Y direction. In this way, the block correction data in the table is obtained by dividing the entire surface of the table into blocks having an interval of, for example, 10 mm and recording the correction values in the XY directions in each block.

In the block correction process, the correction values need to be converted into pixels in order to transform the image data. It is assumed that the correction value is converted by setting a predetermined threshold according to the measured correction value and print resolution. For example, in an image with a resolution of 2880 dpi and a pixel resolution of 8.8 μm, if the amount of displacement is from 0 to 4.4 μm, the block correction data in the table assumes that the block is not moved and moves 0 pixels, and the displacement is from 4.5 μm. If it is 13.2 μm, it is moved by 1 pixel, if the amount of misalignment is 13.3 to 22 μm, it is moved by 2 pixels, and if the amount of misalignment is from 22.1 to 30.8 μm, it is moved by 3 pixels, and so on. is assumed to be set.

According to the threshold setting example described above, the number of pixels moved from the left to the first row in FIG. The second row is 0, 0, 0, 1, 1, 1, 1, and the third row is 0, 0, 0, 1, 1, 1, 1. Likewise, how many pixels are moved according to the threshold is set. In the case of the 7th row, it is -1, -1, -1, 0, 0, 0, 0, but if there is a - like this, the direction of movement is reversed.

As described above, the intra-table block correction data of FIGS. 14B and 14C are stored in the storage means 51 as information relating to the relative positional deviation between the table 14 and the ink jet head 1, and are processed as described above. , before printing, it is possible to divide, move, and combine the image to be printed.
Note that a value after conversion into the number of pixels may be stored in the storage unit 51 as the in-table block correction data.

The process of block correction processing in the first embodiment described above will be described using a flowchart. FIG. 15 is a flow chart for explaining the first embodiment. FIG. 15(a) shows the process performed before executing the printing operation, and FIG. 15(b) shows the process performed in each printing operation. This block correction processing is executed by the control personal computer 12 in which a program corresponding to the flow of FIG. 15 is stored.

First, the flowchart of FIG. 15(a) will be described. In flow 101, the glass scale 25 is placed on the table 14. Next, in flow 102, the reference mark 26 placed on the glass scale 25 on the table 14 is imaged using the camera 5 by the processing of the control personal computer 12. Then, the center coordinates are calculated based on the obtained image data, and the coordinate position of the reference mark 26 is measured. In flow 103, the difference between the coordinate position data output from the linear encoder and the corresponding position coordinate data of the reference mark 26 is calculated by processing of the control personal computer 12. FIG. Then, in flow 104, a virtual block corresponding to each reference mark 26 is set on the table 14 by the processing of the control personal computer 12, and the correction value obtained by the method of flow 103 is applied to this virtual block. For this purpose, create the block correction data in the above table. Then, in flow 105 , the in-table block correction data is stored in the storage means 51 by the processing of the control personal computer 12 . The above steps are steps to be performed before execution of the printing operation. Note that the above steps can be performed before manufacturing the inkjet recording apparatus, or can be performed as appropriate depending on the state of print quality after manufacturing.

Next, the flowchart of FIG.15(b) is demonstrated. First, in flow 106, block correction data in the table is acquired from the storage means by the processing of the control personal computer 12. FIG. Next, in flow 107, the print image data is divided into blocks by the processing of the control personal computer 12, and the movement amount of each block is calculated in units of pixels from the coordinates of the print start position, the block correction data in the table, and the print resolution. In the step of flow 107, the block correction data in the table recorded in the unit of μm is changed to the unit of pixel according to the print image by the processing of the control personal computer 12, and furthermore, the position coordinate on the table 14 is changed to the recording medium. It is also possible to reflect the information as to whether or not is placed, and perform block correction of the image data.
Then, in flow 108, each block is moved by processing of the control personal computer 12 according to the movement amount calculated in flow 107, and in flow 109, the moved blocks are combined to generate image data.

Through the above steps, block correction processing is performed on print image data, and machine precision errors can be corrected.

By the way, the above machine accuracy error may vary depending on the temperature conditions of each member constituting the inkjet recording apparatus. 1, the X-axis drive unit 8, the Y-axis drive unit 15, the linear encoders mounted on each drive unit, the gate-type mount on which the X-axis drive unit 8 is assembled, Members such as the table 14 and the base plate 16 are made of a plurality of materials such as aluminum and iron, and each material has a different coefficient of thermal expansion. In addition, it is assumed that the occurrence of machine accuracy errors due to temperature changes also varies depending on the assembling conditions of each member, such as the tightening strength of screws. Therefore, a plurality of table block correction data corresponding to the temperature conditions of the inkjet printing apparatus are obtained in advance, and the corresponding table block correction data are referred to according to the temperature conditions of the inkjet printing apparatus to perform block correction processing. can be implemented.

FIG. 16 is a conceptual diagram for explaining switching of block correction data in the table and block correction processing according to the temperature condition of the inkjet printing apparatus. In the example of FIG. 16, for example, block correction data in the table for each temperature of 4° C. is prepared in advance by the process described with reference to FIG. Then, according to the temperature information acquired from the temperature sensor 19 mounted on the inkjet recording apparatus, the control personal computer 12 acquires from the block correction data in the table of each temperature stored in the recording means via the selection means 55. The table block correction data closer to the received temperature information is selected, referred to, and used for block correction processing.

If it is necessary to select in-table block correction data according to more detailed temperature changes, it is also possible to store in-table block correction data for each more detailed temperature, or to store in-table block correction data according to two adjacent temperatures. Correction data can be used to linearly interpolate to generate in-table block correction data corresponding to the temperature between the blocks. For example, in the example of FIG. 16, if you want to create a block correction table in the table for 21° C., as an example, each element (A) in the table for 20° C. and each element (B) in the table for 24° C. (A* It can be obtained by linear interpolation of 3+B*1)/4.

Furthermore, a second embodiment according to the present invention will be described with reference to FIGS. 17 to 26. FIG.

As a second embodiment, a first block correction process for applying a block correction process of image data according to a shape error of a recording medium, and a block correction process in the first embodiment as a second block correction process. An example of applying is described.

As an example suitable for applying the second embodiment, the recording medium is a printed wiring board on which a copper pattern has already been formed, and the resist material, which is an insulator in the inkjet recording apparatus, is used in the manufacture of the printed wiring board. A case where it is applied as a post-process is assumed. In such a case, the shape of the printed wiring board itself, the copper pattern formed by the exposure apparatus, etc. may cause slight errors in formation accuracy. , it is assumed that it is necessary to adjust the position to which the resist material is to be applied in a post-process stage.

FIG. 17 is a schematic diagram showing an example of a printed wiring board of a recording medium. The printed circuit board 53 has a wiring pattern portion 58, which is an area in which wiring is formed of a conductor such as copper or silver. A plurality of alignment marks 54 (four places in the example of FIG. 17) are arranged according to the arrangement relationship. In the case of applying the resist material using the inkjet recording apparatus of FIG. If there is a difference in the coordinate positions of the alignment marks captured by the camera, it is necessary to transform the image data according to the coordinate positions of the alignment marks captured by the camera 5 . Through this process, the resist material can be applied to the intended position without any accuracy error based on the image data deformed according to the accuracy error occurring in the printed wiring board 53 .

The reading of the alignment marks 54 of the printed wiring board 53 will be described below.

FIG. 18 is a schematic diagram showing how alignment marks on a printed wiring board are read using a camera. FIG. 18(a) is a schematic diagram of an imaging frame of the camera 5. FIG. 10, the outer camera frame 27 shows the entire field of view of the camera 5. For example, if the number of pixels is 1280×1024 and the resolution per pixel is 5 μm, the field of view in the X direction is 1280×1024. Pixels×5 μm=6.4 mm, and the field of view in the Y direction is 1024 pixels×5 μm=5.12 mm. An intersection point 28 of dotted lines indicates the center of the camera frame 27 . For the arranged alignment marks 54, the shape accuracy error of the printed wiring board 53 can be measured by measuring the amount of deviation between the alignment marks 54 and the intersections 28 respectively.

The alignment mark 54 is read by the camera 5 according to the mounting position of the printed wiring board 53 on the table 14 . Therefore, the information of the mounting position coordinates of the recording medium 17 on the table 14, such as deviation and inclination of the mounting position of the printed wiring board 53, which is a type of the recording medium 7, on the table 14 is It is also grasped by reading the alignment mark 54 of 53 . Using the data corresponding to the coordinates of the in-table block correction data on the table 14 according to the information of the placement position coordinates of the recording medium 17 on the table 14 grasped here, the first Two block correction processes are performed.

FIG. 18(b) shows an example of the imaging state of the alignment mark 54, showing how the alignment mark 54 with a diameter of 0.5 mm is imaged at the intersection 28 which is the center of the camera frame 27. FIG. The fact that the alignment mark 54 is imaged as shown in FIG. 18(b) means that there is no accuracy error at the position of the alignment mark 54 shown in FIG. 18(b).

FIG. 18(c) is also an example of an imaging situation of the alignment mark 54. In this example, the alignment mark 54 is arranged in the X direction and the Y direction from the intersection 28 of the camera frame. 32 shows a state in which images are taken with a shift of an amount corresponding to 32. The fact that the image is captured as shown in FIG. 18(c) means that an accuracy error has occurred at the position of the alignment mark 54 shown in FIG. 18(c), and correction is required. ing. An X-coordinate correction value 31 and a Y-coordinate correction value 32 in FIG. When the resolution per pixel of the camera 5 is 5 μm as in the above example, the values of the X-coordinate correction value of 31×5 μm and the Y-coordinate correction value of 32×5 μm are the amounts of deviation. Even if the resolution of the camera is 5 μm/pixel, the coordinates of the alignment mark 54 are measured at the center of gravity, so they can be measured with a finer resolution than 5 μm. The image data is transformed using the correction values acquired here.

First, as a premise for the description of the second embodiment, a deformation process of deforming image data according to the accuracy error of the printed wiring board 53 using correction values based on the alignment marks obtained by the method described with reference to FIG. An example will be described.

In this description, the coordinates of the alignment marks on the image data are (X1, Y1), (X2, Y2), (X3, Y3), and (X4, Y4), and the alignment marks of the printed wiring board 53 calculated by the camera 5 are Let the coordinates be (x1, y1), (x2, y2), (x3, y3), (x4, y4). Here, the shapes of (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4) are (x1, y1), (x2, y2), (x3, y3), (x4, y4) is performed on the image data.

From the quadrangle formed by the four-point coordinates (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4), (x1, y1), (x2, y2), ( x3, y3), (x4, y4) The transformation process to a quadrangle formed by the four-point coordinates is not simple translation, rotation, or scaling in the XY directions, but from an arbitrary quadrangle to another arbitrary quadrangle. to any quadrangle transform coefficients that are transforms of . Therefore, for example, the conversion of (Xi, Yi) to (xi, yi) uses the following formula to calculate an arbitrary quadrangle conversion coefficient for conversion to an arbitrary quadrangle.
xi=A*Xi*Yi+B*Xi+C*Yi+D
yi=E*Xi*Yi+F*Xi+G*Yi+H
Here, B is the main coefficient of xi and indicates the scaling factor in the X direction. A and C are coefficients that affect Y and are used to express distortion. D is a coefficient representing translation. Similarly for E, F, G, and H, G is the main coefficient of yi and indicates the scaling factor in the Y direction. E and F are coefficients that affect X and are used to express distortion. H is a coefficient representing translation. Since there are a total of 8 equations here, 8 variables can be obtained.
Formula 1;
x1=A*X1*Y1+B*X1+C*Y1+D
x2=A*X2*Y2+B*X2+C*Y2+D
x3=A*X3*Y3+B*X3+C*Y3+D
x4=A*X4*Y4+B*X4+C*Y4+D
y1=E*X1*Y1+F*X1+G*Y1+H
y2=E*X2*Y2+F*X2+G*Y2+H
y3=E*X3*Y3+F*X3+G*Y3+H
y4=E*X4*Y4+F*X4+G*Y4+H
An arbitrary point (Xi, Yi) can be converted to (xi, yi) using the numerical values of A, B, C, D, E, F, G, and H calculated by this formula.

By the way, the above modified processing example also has the same problem as the problem explained in the first embodiment. That is, since this process has an element of scaling of the image data by its nature, a phenomenon that one pixel line disappears due to reduction or a phenomenon that one pixel line becomes two pixel lines due to enlargement may occur. FIG. 3 is a schematic diagram showing an example of a phenomenon that occurs when scaling is performed. As shown in FIG. 3, a phenomenon that one pixel line disappears due to reduction and a phenomenon that one pixel line becomes two pixel lines due to enlargement may occur. These phenomena do not necessarily occur during enlargement/reduction, but may occur with a certain probability depending on the enlargement/reduction magnification. For example, if the image data of 1000×1000 pixels is reduced to 99%, it is necessary to delete 1 pixel out of 100 pixels, or 10 pixels in total. sexuality occurs. Also, if you reduce it to 101%, it is necessary to increase the image by 1 pixel per 100 pixels, or a total of 10 pixels. sexuality occurs. Occurrence of such a phenomenon causes a phenomenon in which printing is not performed on a portion that should be printed or a phenomenon in which printing is performed on a position that should not be printed. If such a phenomenon occurs, the print quality may be greatly affected when it is necessary to print on a recording medium such as the printed wiring board 53 that requires high-precision printing.

Therefore, in the second embodiment, it is effective to perform the block correction process even when deforming the image data according to the accuracy error of the shape of the recording medium.

FIG. 19 is a schematic diagram illustrating how a quadrangle having four vertices corresponding to alignment marks in image data is converted into a quadrangle having four vertices corresponding to alignment marks on a printed wiring board as a recording medium. For convenience of explanation, the coordinates of the four vertices of the alignment marks in the image data 44 are (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4), and the alignment of the printed wiring board 53 is performed. Assume that the four vertices of the mark are (x1, y1), (x2, y2), (x3, y3), and (x4, y4). The image data 44 is assumed to be a square of P pixels vertically and horizontally, and the block size is also assumed to be L pixels vertically and horizontally.

The image data 44 is normally rectangular, and when it is aligned with the copper foil of the printed circuit board, it is assumed that the rectangular image data will be the image shape 60 after the deformation of the block correction for the shape error, and the print image data at that time is the shape It becomes the image data shape 61 after deformation of the block correction for the error. In this example, the image data 44 is divided into a total of 400 blocks 47, 20 in length and width.
As described above, if the maximum movement distance between adjacent blocks 47 is within one pixel, the maximum enlargement size is P+19 pixels and the minimum reduction size is P-19 pixels in both the Y and X directions. If the image data of the image shape 60 cannot be generated even with this maximum enlargement size P+19 pixels, the number of divisions of the block 47 must be greater than 20.

Here, for convenience of explanation, the coordinates of the four vertices of the alignment mark in the image data 44 (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4) and the printed wiring Assume the following coordinates (x1, y1), (x2, y2), (x3, y3), and (x4, y4) of the four vertices of the alignment mark 54 on the substrate 53 .
Condition 1;
(X1, Y1)=(0,0), (X2, Y2)=(200,000,0),
(X3, Y3) = (200,000, 200,000), (X4, Y4) = (0, 200,000)
(x1, y1) = (0, 0), (x2, y2) = (199, 900, -100),
(x3, y3) = 200, 100, 200, 100), (x4, y4) = (-100, 199, 900)
The unit is μm. That is, the upper left origin coincides, the upper right corner is located at minus 100 μm after deformation in both XY, the lower right corner is located at plus 100 μm after deformation in both XY, and the lower left corner is minus 100 μm after deformation in both XY. positioned. Since P is 200 mm and the amount of deviation of the coordinates of the four points is 100 μm at maximum, the deformation is not large enough to be visually obvious as shown in FIG. are doing. The numerical values of (X1, Y1), (X2, Y2), (X3, Y3), and (X4, Y4) can actually be obtained from the image data, and (x1, y1), (x2) , y2), (x3, y3), and (x4, y4) are generated by measuring the alignment mark 54 captured by the camera 5 as described in FIG.

Next, the transform coefficients A, B, C, D, E, F, G, and H described above are obtained.
Substitute the condition 1; into the formula 1; to obtain the transform coefficients A, B, C, and D.
0=A*0*0+B*0+C*0+D
199900 = A * 200000 * 0 + B * 200000 + C * 0 + D
200100 = A * 200000 * 200000 + B * 200000 + C * 200000 + D
-100 = A * 0 * 200000 + B * 0 + C * 200000 + D
Solving the four simultaneous equations gives A=7.5E-09, B=0.9995, C=-0.0005, and D=0.
Here, B is the main coefficient of xi and indicates the scaling factor in the X direction, which is 0.9995, which is a value close to 1. A and C are coefficients that affect Y and are used to express distortion. Since the distortion is small, the values of A=7.5E-09 and C=-0.0005 are considerably small. D is a coefficient representing parallel movement, but it is 0 here because there is no parallel movement.

Further, the condition 1; is substituted into the formula 1; to obtain the transform coefficients E, F, G, and H.
0=E*0*0+F*0+G*0+H
-100=E*200000*0+F*200000+G*0+H
200100=E*200000*200000+F*200000+G*200000+H
199900=E*0*200000+F*0+G*200000+H
Similarly, solving four simultaneous equations gives E=7.5E-09, F=-0.0005, G=0.9995, and H=0.

Using A, B, C, D, E, F, G, and H obtained above, all pixels (Xi, Yi) of 59 image data can be converted into a shape (xi, yi) after 60 transformations. can.
xi=A*Xi*Yi+B*Xi+C*Yi+D
yi=E*Yi*Yi+F*Yi+G*Yi+H
In this formula, the post-conversion position in units of μm is calculated, so dividing that value by the pixel resolution, for example, 10.58 μm for 2400 dpi and 8.8 μm for 2880 dpi, the number of pixels to be moved is calculated. be.

FIG. 20 is a list in which the numbers of moving pixels calculated as a result of the above calculation are arranged for each block according to the arrangement of the blocks. It should be noted that the units of numerical values displayed in the blocks are pixels. In the example of FIG. 20, the image data after deformation is a square, and the deformation in the X and Y directions is symmetrical as a result. If the deformation is not symmetrical, the table may differ between the X direction and the Y direction.

For example, the upper left coordinates of the 10th block in the X direction and the 10th block in the Y direction of the image data are X=90000, Y=90000. In terms of distance, both XY are 89,970-90000=-28 μm, and if the resolution is 2400 dpi, 1 pixel is about 10.58 μm, and -28/10.58=2.65 pixels, which is rounded off by 3 pixels in the minus direction. result in moving to In the example of FIG. 20, the amount of block movement is a maximum of 8 pixels and a minimum of -9 pixels. This is due to the effect of designating the representative value of the block in the direction of the upper left origin, and is a reasonable value considering that the maximum deviation at the edge of FIG. 19 is ±100 μm. Also, it can be understood that the difference in numerical values between adjacent blocks on the top, bottom, left, and right is 1 or less, and that the adjacent blocks are shifted by a maximum of one pixel. When the same value is adjacent, there is no distance difference between adjacent blocks with the same value because they are moved by the same amount.

Through the above process, block correction processing of image data according to the shape error of the recording medium can be realized. For example, when applying a resist material, which is an insulator in an inkjet recording apparatus, to a printed wiring board on which a copper pattern is formed, as a post-manufacturing process of the printed wiring board, there is a slight precision error for each printed wiring board. Even if there is, by performing block correction processing on the image data in accordance with the alignment mark, the phenomenon that one pixel line disappears or one pixel line becomes two pixel lines can be avoided, and the copper pattern can be corrected. On the other hand, it becomes possible to perform printing that applies a resist material with high accuracy.

Then, after performing the block correction processing of the image data according to the shape error of the recording medium, the block correction processing according to the machine accuracy error described in the first embodiment is further performed. high-precision printing can be realized.

The flow of processing in the second embodiment as described above will be described with reference to FIG. FIG. 21 is a chart for explaining the overall flow of processing in the first example of the second embodiment. These processes are executed by the control personal computer 12 according to corresponding programs.
A first block correction process is performed in a chart 63 on the print image data designated as a print target in the chart 62 based on the correction value according to the shape error of the recording medium based on the alignment marks measured in the chart 65. Then, the first post-correction print image data corrected according to the shape of the recording medium is generated. Furthermore, referring to the in-table block correction data obtained according to the machine accuracy error in the chart 67 and the mounting position coordinates of the recording medium 7 on the table 14 in the chart 66, the mounting position coordinates of the recording medium 7 are obtained. Using the block correction data in the table according to the table 64, the second block correction process according to the machine precision error described in the first embodiment is further performed on the print image data after the first correction in the chart 64, and 2 Print image data after correction for the first time is generated. The order of generating the first post-correction print image data corrected according to the shape of the recording medium and the second post-correction print image data corrected according to the machine precision error does not matter. Finally, it is possible to generate print image data in which both the shape error and the machine precision error of the recording medium are corrected.

At this time, the first block correction process and the second block correction process may overlap and the amount of block movement may be doubled.

In the first example of the second embodiment, the sizes of blocks set in the first block correction processing and the second block correction processing are unified, and the first block correction processing and the second block correction processing are performed. By shifting the boundaries of the blocks set in , and setting them so as to have a predetermined phase so as not to overlap each other, the amount of movement of one block is prevented from exceeding one pixel. FIG. 22 is a schematic diagram showing a situation in which predetermined phases are set after unifying block sizes in the first block correction process and the second block correction process. In the example of FIG. 22, in the first block correction process and the second block correction process, the size is unified so that the block movement amount does not exceed 1 pixel, and then the starting origin position of the first block correction process is set. An origin 73 and an origin 74, which is the starting origin position of the second block correction process, are moved within the range of one block. By moving the entire block of , different phases are set, and two phases, a first phase 68 and a second phase 69 indicated by a solid line, are set as shown in the figure. Block correction processing is performed in the first phase 68 in the first block correction processing, and block correction processing is performed in the second phase 69 in the second block correction processing. Then, since the movement of blocks by the second block correction process is executed at different positions, the movement of blocks is executed at the same boundary (block) in the first block correction process and the second block correction process. , and it is possible to avoid moving one block by more than one pixel.

Further, when block movement by the first block correction process and block 47 with a movement amount of more than one pixel are generated by the second block correction process, as described with reference to FIG. It is also possible to further divide the block 47 in which is more than one pixel, and move each divided block by one pixel.

A first example of the second embodiment will be described again using a flow chart and an example in which the printed wiring board 53 is used as the recording medium. FIG. 24 is a flow chart showing the flow of the first example in the second embodiment. Each process described in the flowchart is executed by the control personal computer 12 in which a program corresponding to the flow is stored. In flow 121 , the printed wiring board 53 is placed on the table 14 . Next, in flow 122 , the camera 5 is used to image the alignment mark 54 arranged on the printed wiring board 53 , and the center coordinates are calculated by the processing of the control personal computer 12 . This corresponds to the processing described in FIG. Next, in flow 123, an arbitrary quadrangle conversion coefficient is calculated from the difference between the alignment mark position coordinate data of the image data and the coordinate data of the alignment mark 54 of the printed wiring board 53 acquired in flow 122 by the processing of the control personal computer 12. do. This corresponds to the content described in FIG. Next, in flow 124, the image data is divided into blocks by the processing of the control personal computer 12, and the representative points of each block are transformed using arbitrary quadrangle transformation coefficients. This also corresponds to the content explained in FIG. Next, in flow 125, the movement amount of each block is calculated from the difference before and after the conversion and the print resolution by the processing of the control personal computer 12. FIG. This corresponds to the content explained in FIG. Next, in flow 126, each block is moved according to the movement amount by the processing of the control personal computer 12. FIG. Next, in flow 127, the moved blocks are synthesized by the processing of the control personal computer 12 to regenerate the image data. Furthermore, in flow 128, the temperature inside the printing apparatus is measured. Next, in flow 129, block correction data in the table corresponding to the temperature measured in flow 128 is selected by the processing of the control personal computer 12 and referred to by the recording means. Next, in flow 130, the image data is divided into blocks in different phases by the processing of the control personal computer 12, and block correction within the table is performed according to the placement position coordinates of the recording medium 7 based on the print start position and the block correction table within the table. The amount of movement of each block is calculated using the data. This corresponds to the description of FIG. Then, in flow 131, each block is moved according to the movement amount by the processing of the control personal computer 12. FIG. Finally, in flow 132, the blocks moved by the processing of the control personal computer 12 are combined to generate image data again.

In the second embodiment, as a second example, reference is made in advance to the correction value corresponding to the shape error of the recording medium based on the alignment mark, the block correction data in the table, and the placement of the recording medium. After referring to the coordinates and referencing the entire block movement amount, the final block movement amount is calculated. It is also possible to generate print image data in which both shape errors and machine precision errors of the recording medium are corrected.

FIG. 25 is a chart diagram explaining an overview of a second example in the second embodiment. In the example of FIG. 25, the block movement amount (1) is calculated in chart 70 based on the correction value corresponding to the shape error of the recording medium based on the alignment marks measured in chart 65 . Furthermore, after referring to the in-table block correction data obtained according to the machine accuracy error in the chart 66, the placement coordinates of the recording medium 7 on the table 14 are referred to in the chart 67, and the placement of the recording medium 7 is performed. A block movement amount (2) is calculated in the chart 71 using block correction data in the table corresponding to the position coordinates. Further, in the chart 72, the block movement amount (1) and the block movement amount (2) are totaled to calculate the final block movement amount. Then, by applying the final block movement amount calculated in the chart 72 to the print image data in the chart 63, which is designated as the print target by the command from the control personal computer 12 in the chart 62, Print image data is generated by correcting both the shape error and the machine precision error of the recording medium. As in the example of FIG. 21, the order of the charts 70 and 71 may be reversed, and finally print image data can be generated in which both the shape error and the machine precision error of the recording medium are corrected. .

Also in the second example of the second embodiment, it is effective to keep the amount of movement of the block 47 within one pixel in order to avoid deterioration of print quality due to block correction. Various methods are conceivable for keeping the amount of movement of the block 47 within one pixel. As described above, when there is a block 47 whose movement amount exceeds one pixel, by setting the size of all the blocks 47 to be smaller, the movement amount of each block 47 is It can fit within one pixel. In this case as well, the amount of block 47 to be moved can be minimized, and from the viewpoint of improving the processing speed, the amount of movement of block 47 can be set to a maximum size within one pixel. As another method for keeping the amount of movement of the block 47 within one pixel, as described with reference to FIG. It is also possible to use a method of further dividing only the blocks 47 that are different from each other and moving each of the divided blocks 47 by one pixel.

A second example of the second embodiment will be described again using a flow chart and an example in which the printed wiring board 53 is used as the recording medium. FIG. 26 is a flow chart showing the flow of a second example in the second embodiment. Each process described in the flowchart is executed by the control personal computer 12 in which a program corresponding to the flow is stored. In flow 121 , the printed wiring board 53 is placed on the table 14 . Next, in flow 122 , the camera 5 is used to image the alignment mark 54 arranged on the printed wiring board 53 , and the center coordinates are calculated by the processing of the control personal computer 12 . This corresponds to the processing described in FIG. Next, in flow 123, the processing of the control personal computer 12 calculates an arbitrary quadrangle conversion coefficient from the difference between the alignment mark position coordinate data of the image data and the coordinate data of the alignment mark 54 of the printed wiring board 53 acquired in flow 122. do. This corresponds to the content described in FIG. Next, in flow 124, the image data is divided into blocks by the processing of the control personal computer 12, and the representative points of each block are transformed using arbitrary quadrangle transformation coefficients. This also corresponds to the content explained in FIG. Next, in flow 125, the block shift amount (1) is calculated from the difference before and after the conversion and the print resolution by the processing of the control personal computer 12. FIG. This corresponds to the content explained in FIG. The above is the same as the first example. Next, in flow 128, the temperature inside the printing apparatus is measured. Next, in flow 129, block correction data in the table corresponding to the temperature measured in flow 128 is selected by the processing of the control personal computer 12 and referred to by the recording means. A numerical value obtained by referring to block correction data in the table corresponding to the mounting position coordinates of the recording medium 7 is set as the block movement amount (2). Next, in flow 130, the block movement amount (1) and the block movement amount (2) are combined by the processing of the control personal computer 12 to calculate the final movement amount of each block. Then, in flow 131 , each block is moved according to the movement amount calculated in flow 130 by processing of the control personal computer 12 . Finally, in flow 132, the control personal computer 12 processes to combine the moved blocks to generate image data.

By carrying out the printing operation through the above process, it was possible to achieve printing with even higher precision.

1 Inkjet head 2 Carriage 3 Control board 4 Sub-tank 5 Camera 6 Camera illumination 7 Recording medium 8 X-axis drive unit 9 Negative pressure pump 10 Main tank 11 Pump 12 Control personal computer 13 Interface board 14 Table 15 Y-axis drive unit 17 Three-way valve 18 Positive pressure pump 19 Temperature sensor 25 Glass scale 26 Reference mark 27 Camera frame 31 X coordinate correction value 32 Y coordinate correction value 44 Image data 45 Image shape after deformation 46 Image data after conversion 47 Block 51 Storage means 52 Linear encoder coordinates 53 Printed wiring board 54 Alignment mark 55 Selection means 60 Image shape 61 Image data shape 76 Representative point

Claims (23)

a table on which a recording medium is placed;
a recording head that ejects a recording agent onto the recording medium placed on the table;
moving means for relatively moving the table and the recording head in order to perform recording on the recording medium according to image data;
a control means for instructing the moving means to move the table and the recording head relative to each other according to a predetermined amount of movement;
an error between the predetermined movement amount commanded by the control means for the movement means and the actual relative movement amount between the table and the recording head by the movement means according to the command by the control means; Acquisition means for acquiring information related to
a first correcting means for correcting the image data according to the information about the error acquired by the acquiring means;
has
The first correction means divides the image data into a plurality of blocks each corresponding to each of the plurality of positions of the table, and divides each of the plurality of blocks into a relative position of the corresponding recording head. and correcting the image data by moving the plurality of positions in accordance with the respective errors. The moving means includes means for relatively moving the table and the recording head in a first direction, and moving the table and the recording head in a second direction substantially orthogonal to the first direction. and means for relatively moving, and the information about the error includes information about the error in the first direction and the second direction. Recording device as described. 3. A recording apparatus according to claim 1, wherein said first correction means comprises storage means for storing information relating to said error. The storage means stores a plurality of information relating to the error for each temperature of the recording device, and the first correction means determines the temperature of the recording device from the plurality of information relating to the error stored in the storage means. 4. The recording apparatus according to claim 3, wherein the error information is selected according to the error, and the block is moved according to the selected error information. Using two or more pieces of information related to the error for each temperature stored in the storage means, further calculating information related to the error according to the temperature not stored in the storage means, 5. A recording apparatus according to claim 4. In the first correcting means, when an area where pixels overlap between adjacent blocks occurs when the block is moved, the image data of the overlapping area is subjected to logical sum processing. 6. The recording apparatus according to any one of claims 1 to 5. 7. The method according to any one of claims 1 to 6, wherein said first correction means further divides said block when the amount of movement of said block exceeds a predetermined first specified amount. 1. The recording device according to 1. 8. A recording apparatus according to claim 7, wherein said first specified amount is one pixel. 2. The recording medium according to claim 1, further comprising shape information acquisition means for acquiring shape information relating to the shape of said recording medium, and second correction means for correcting said image data according to said shape information. 9. A recording apparatus according to claim 8. The recording medium has a recording area in which the image data is recorded, and a plurality of alignment marks arranged in an outer peripheral area of the recording area in a predetermined positional relationship with respect to the recording area,
10. The recording apparatus according to claim 9, wherein said shape information acquiring means acquires said shape information based on position information of said plurality of alignment marks on said recording medium placed on said table. . 10. The second correction means corrects the image data by dividing the image data into a plurality of blocks and moving the plurality of blocks according to the shape information. 11. A recording apparatus according to claim 10. The size of the blocks divided by the first correcting means and the size of the blocks divided by the second correcting means are equal, and the size of the blocks divided by the first correcting means and the second correcting means are equal 12. The recording apparatus according to claim 11, wherein the boundaries of said blocks are different from each other. In the first correcting means or the second correcting means, when an area where pixels overlap between adjacent blocks occurs when the block is moved, the image data of the overlapping area is logically summed. 13. A recording apparatus according to claim 11 or 12, characterized by processing. 14. The block according to any one of claims 11 to 13, wherein said second correction means further divides said block when the amount of movement of said block exceeds a predetermined second specified amount. 1. The recording device according to 1. 15. A recording apparatus according to claim 14, wherein said specified amount is one pixel. a table on which a recording medium is placed;
a recording head that ejects a recording agent onto the recording medium placed on the table;
moving means for relatively moving the table and the recording head in order to perform recording on the recording medium according to image data;
a control means for instructing the moving means to move the table and the recording head relative to each other according to a predetermined amount of movement;
an error between the predetermined movement amount commanded by the control means for the movement means and the actual relative movement amount between the table and the recording head by the movement means according to the command by the control means; a storage means for storing information relating to
shape information acquisition means for acquiring shape information relating to the shape of the recording medium;
correction means for dividing the image data into a plurality of blocks each corresponding to each of the plurality of positions of the table, and correcting the image data by moving each of the plurality of blocks;
has
The correction means causes each of the plurality of blocks to move by a movement amount according to the information related to the error stored in the storage means and the shape information acquired by the shape acquisition means. A recording device characterized by: The moving means includes means for relatively moving the table and the recording head in a first direction, and moving the table and the recording head in a second direction substantially perpendicular to the first direction. 17. A recording apparatus according to claim 16, wherein said information includes information relating to errors in said first direction and said second direction. . The storage means stores a plurality of information related to the error for each temperature of the recording device, and the correction means stores a plurality of information related to the error stored in the storage means according to the temperature of the recording device. 18. The recording apparatus according to claim 16, wherein the error information is selected, and the block is moved according to the selected error information. Using two or more pieces of information related to the error for each temperature stored in the storage means, further calculating information related to the error according to the temperature not stored in the storage means, 19. A recording apparatus according to claim 18. The recording medium has a recording area in which the image data is recorded, and a plurality of alignment marks arranged in an outer peripheral area of the recording area in a predetermined positional relationship with respect to the recording area,
16. The shape information acquiring means acquires the shape information based on position information of the plurality of alignment marks on the recording medium placed on the table. 20. The recording apparatus according to any one of 19. 2. In said correcting means, when an area where pixels overlap with said adjacent block occurs when said block is moved, said image data of said overlapping area is logically sum-processed. 21. A recording apparatus according to any one of claims 16-20. 22. The apparatus according to any one of claims 16 to 21, wherein said correction means further divides said block when the amount of movement of said block exceeds a predetermined amount. recording device. 23. A recording apparatus according to claim 22, wherein said specified amount is one pixel.

Images