Inkjet recording apparatus and inkjet recording method

Abstract

To solve such the problem that there is a concern when a vicinity of the center of a bar code part becomes a boundary of recording scanning which may affect bar code reading accuracy.SOLUTION: When a length of a bar code part is longer than a length recorded by one scanning operation and shorter than twice the length, transportation of a recording medium is controlled so as to record the bar code part with three scanning operations.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus and an inkjet recording method for recording an image on a recording medium. [Background technology]

[0002] In recent years, inkjet printing devices have become known that perform so-called multi-pass printing, which prints an image by scanning a unit area multiple times. Such inkjet printing devices print an image on a printing medium by repeatedly controlling the transport of the printing medium and scanning a carriage equipped with a printing head.

[0003] Patent Document 1 describes a recording system for recording barcodes. It is assumed that the barcodes recorded on the recording medium will be optically read, and it is therefore required that a highly accurate barcode image be recorded. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-150211 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, when an inkjet recording device records a barcode using two or more recording scans, there is a possibility that transport control will be performed between the recording scans. In this case, if the transport accuracy for transporting the recording medium is low, an error will occur in the transport amount, which may result in changes in the line width of each bar that makes up the barcode, line jaggedness, or blank areas.

[0006] This deterioration in barcode quality can affect the reading of barcodes recorded on recording media. Generally, the area near the center of a barcode is easier to read, and if there is any wobble near the center of the bar, it may not be read accurately or may take a long time to read.

[0007] In view of the above problems, the present invention aims to provide a recording device that can suppress degradation of image quality near the center of the bars in a barcode and suppress the influence of recording medium transport during reading. [Means for solving the problem]

[0008] The present invention is a recording apparatus comprising: a conveying means for conveying a recording medium in a first direction; a recording means having a nozzle row in which a plurality of nozzles for ejecting ink are arranged along the first direction, and for recording an image on the recording medium conveyed by the conveying means by scanning in a second direction intersecting the first direction; and a control means for controlling the conveying means and the recording means so as to record the image on the recording medium by performing a conveying operation for conveying the recording medium and a recording operation by scanning the recording means based on image data of an image including a barcode portion formed by a plurality of bars, wherein the control means controls conveyance of the recording medium by the conveying means so that the barcode portion is recorded by three scans by the recording means when the length in the first direction of the barcode portion recorded on the recording medium is longer than a first length which is the length in the first direction of an area recorded by the recording means in one scan and shorter than twice the first length. The amount of conveyance of the recording medium performed by the conveying means between two scans of the recording means is the first length. It is characterized by the following. [Effects of the Invention]

[0009] The present invention can suppress degradation of image quality near the center of the bars in a barcode, and can suppress the influence of the conveyance of a recording medium during reading. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of an inkjet printer [Figure 2] Schematic diagram of the print head 303 as viewed from the nozzle formation surface [Figure 3] Block diagram of the control configuration of the inkjet printing system [Figure 4] Recording system overview block diagram [Figure 5] Flow diagram of image data processing performed by an image processing device [Figure 6] Schematic diagram showing a connecting portion when recording a barcode, which is an object of the present invention. [Figure 7] Perspective view of a barcode reader [Figure 8] Schematic diagram showing a connecting portion when recording a barcode in the first embodiment. [Figure 9] Flow diagram for adjusting the transport amount in the first embodiment. [Figure 10] Schematic diagram showing the feed amount and band data when adjusting the feed amount [Figure 11] 10 is a schematic diagram showing a connecting portion when recording a barcode in a modified example of the first embodiment. [Figure 12] Schematic diagram showing a connecting portion when recording a barcode in embodiment 2. [Figure 13] Schematic diagram showing a connecting portion when recording a barcode in embodiment 3. [Figure 14] Illustration of the multi-pass printing method DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] The first embodiment will be described below. Note that the following description will be given assuming image processing within the printer body, but this is merely an example of one embodiment, and the present embodiment is not limited to the following.

[0013] (Explanation of Inkjet Recording Apparatus) 1 is a diagram illustrating a printing apparatus according to this embodiment. The printing apparatus according to this embodiment is an inkjet printer employing a so-called serial printing method, and performs multi-pass printing, completing printing of an image in a unit area by multiple relative scans of a print head 303 relative to a print medium P.

[0014] The recording medium P fed to the recording section is transported in the direction of arrow Y in the figure (hereinafter also referred to as the transport direction) by the nip between a transport roller 101 arranged on the transport path and a pinch roller 102 driven by it, as the transport roller 101 rotates.

[0015] The platen 103 is provided at a position facing the ejection port surface where the ejection ports (hereinafter also referred to as nozzles) of the print head 303 are formed. By supporting the back surface of the print medium P from below, the platen 103 maintains a constant distance between the front surface of the print medium P and the ejection surface of the print head 303.

[0016] The recording medium P on which the image has been recorded is nipped between the discharge roller 105 and the spur 106 driven by it, transported in the Y direction as the discharge roller 105 rotates, and discharged onto the paper discharge tray 107. The discharge roller 105 and the spur 106 form components of a second transport means located downstream in the recording medium transport direction.

[0017] The print head 303 is detachably mounted on the carriage 108 in a position where the ejection port surface faces the platen 103 or the print medium P. The carriage 108 moves back and forth in the X direction along two guide rails 109 and 110 by the driving force of a carriage motor. During this movement, the print head 303 performs an ejection operation to eject ink from the ejection ports in accordance with a print signal, and applies ink onto the print medium.

[0018] 2 is a schematic diagram of the print head 303 as viewed from the ejection port surface. In this embodiment, the cyan nozzle row 21, magenta nozzle row 22, yellow nozzle row 23, and black nozzle row 24 are aligned in the X direction as shown in the figure. In each nozzle row, ejection ports (nozzles) for ejecting ink are arranged at equal intervals in the Y direction.

[0019] Each ejection port has a printing element (not shown) inside, and thermal energy is generated when the printing element is driven by electrical energy. This thermal energy causes the ink to bubble, and the ink is ejected as droplets from the ejection port. For simplicity's sake, in the following explanation, a row of multiple ejection ports that eject the same color and amount of ink will be referred to as a nozzle row. This embodiment is not limited to the thermal inkjet printhead described above, and may also be configured to include a piezo inkjet printhead.

[0020] The X direction in which the carriage 108 moves intersects with the Y direction in which the recording medium is transported, and is called the scanning direction. By alternately repeating the main scanning of the carriage 108 and the print head 303, which involves printing, and the transport of the recording medium, multi-pass printing is performed, in which an image is formed in stages on the recording medium P.

[0021] 14 is a diagram for explaining the relationship between the recording medium P and the ejection openings (nozzles) used for image recording during multi-pass recording. Here, the black nozzle row 24 will be used as an example for explanation, but the same applies to the other nozzle rows.

[0022] First, in the first scan, the print head 303 is moved together with the carriage 108 in the +X direction (forward direction) to perform forward printing, which records an image in area A1 using all nozzles. After the first scan, the print medium P is transported in the +Y direction. The transport amount at this time is a length corresponding to all nozzles arranged on the print head 303. Then, the print head 303 is returned together with the carriage 108 in the -X direction (return direction), and then forward printing in the forward direction is performed by the second scan. In the second scan, the print head 303 is again moved together with the carriage 108 in the +X direction to record an image in area A2 using all nozzles. After the second scan, the print medium P is transported in the +Y direction. The transport amount at this time is also a length corresponding to all nozzles. Then, the print medium P is discharged in the +Y direction, and the printing operation ends.

[0023] As described above, the printing method in this embodiment is a one-pass, one-way printing method in which an image of a predetermined area (A1, A2) on the printing medium is completed by a single scan in one direction of the print head 303, and the conveyance distance for one scan is equal to the nozzle length. In other words, the length in the Y direction of the area printed in one print scan is the nozzle length.

[0024] In the above example, after the first scan in the +X direction, the print head 303 is returned by a scan in the -X direction that does not involve a printing operation, and then a second scan in the +X direction is performed. However, the printing operation may be a reciprocating scan in which the scan in the -X direction is a second scan that involves a printing operation. That is, after the first scan, the carriage 108 and print head 303 are not returned in the -X direction, but the print medium P is transported in the +Y direction by the full nozzle length. Then, in the second scan in the -X direction, an image may be printed in area A2 using all the nozzles.

[0025] FIG. 3 is a block diagram illustrating the control configuration of the inkjet printing system of this embodiment. The printing device main control unit 301 controls the entire printing device and is composed of a CPU, ROM, RAM, etc. The print buffer 302 stores image data as raster data before transferring it to the print head 303. The print head 303 is an inkjet printing head with multiple nozzles capable of ejecting ink droplets, and ejects ink from each nozzle according to the image data stored in the print buffer 302. The paper feed / eject motor control unit 304 controls the transport and paper feed / ejection of the printing medium. The interface (I / F) 305 is connected to the image processing device via an I / F signal line 313 and exchanges data signals. The data buffer 306 temporarily stores image data received from the image processing device. The system bus 307 is a bus that connects the various functions of the printing device.

[0026] The image processing device main control unit 308 is mainly responsible for creating images in the image processing device and controlling image data, and is composed of a CPU, ROM, RAM, etc. The interface (I / F) 309 exchanges data signals with the recording device. The display unit 310 displays various information to the user, and can be, for example, an LCD. The operation unit 311 is an operation unit for receiving operations and instructions from the user, and can be, for example, a keyboard or mouse. The system bus 312 is a bus that connects the image processing device main control unit 308 with each function.

[0027] (Recording system overview) 4 is a block diagram for explaining an overview of the recording system of this embodiment. The recording system shown in this figure includes a host PC 401 and a recording device (printer) 407 that records images based on recording data sent from the PC 401. The PC 401 is made up of an application 402, an OS 403, a printer driver 404, and a recording data transmission unit 406. In this embodiment, the recording data sent to the printer 407 is recording data that includes a barcode image.

[0028] The application 402 is an application that can insert barcode data into an image. In response to an instruction from a printer driver 404, the application 402 combines the functions required for image processing provided by the OS 403 with the data obtained from the application 402 to convert it into print data.

[0029] The printer driver 404 rasterizes (bitmaps) the received print data in a rasterization unit 405, converting it into print data in a format that can be received by the printer. The converted print data is sent to a print data transmission unit 406 and transmitted to a printer 407.

[0030] Next, the process in the recording system of this embodiment, up to the point where a predetermined character string is sent to the printer as barcode data, will be described.

[0031] Barcode data is image data that includes so-called barcodes, which are made up of a one-dimensional combination of bars and spaces. In this specification, the black bars that make up a barcode are called "bars" and the white bars are called "spaces." The multiple bars that make up a barcode are arranged in parallel. The bars and spaces are rectangular, and the length of their long sides is called the "bar (or space) length" and the length of their short sides is called the "bar (or space) width." A barcode image is generated by converting a predetermined character string into a format consisting of bars and spaces using a barcode font.

[0032] The widths of the bars and spaces vary depending on the type of barcode. For example, binary level barcodes have two width levels, while multi-level barcodes have multiple width levels, such as four. Generally, multi-level barcodes have a wider range of widths than binary level barcodes. For this reason, multi-level barcodes have a narrower tolerance for width variations and require higher recording accuracy.

[0033] When a character string is input to the application 402, the printer driver 404 is called via the OS 403. Then, barcode font information stored in the printer driver 404 is requested, and the user sets a specified barcode font.

[0034] The barcode font information includes the barcode font name selected from multiple pre-registered barcode types, as well as information such as the height and width of the barcode font, for example, JAN code, CODE39, CODE128, etc. The application 402 then sends the setting values and image data together to the printer driver 404 via the OS 403.

[0035] The data is then rasterized into barcode data consisting of a one-dimensional combination of bars and spaces using a specified barcode font in a rasterization unit 405. The rasterized data is converted into print data in a format that can be received by a printer 407 and transmitted to the printer 407 via a print data transmission unit 406.

[0036] In the present embodiment, the barcode font of the printer driver is called from the application via the OS, but the present invention is not limited to this.

[0037] (Overall flow overview) 5 is a flowchart for explaining image processing performed in the image processing device of this embodiment. The processing shown in this figure may be performed by the host PC 301, or may be performed within the printer 307, or may be performed in a form in which the processing is partially shared and executed.

[0038] In step S501, image data of an image including a barcode portion is input. The input image data may be vector data or bitmap data.

[0039] In step S502, the input image data is rendered. At this time, the vector data is rasterized. Here, mapping and imposition may be performed according to the size of the recording medium on which the image is recorded. Of the pixels arranged in a matrix, pixel data corresponding to one column of pixels aligned in a specific direction is referred to as raster data. Furthermore, multiple such columns are referred to as band data. If the ROM and RAM capacity of the printer 407 is small, one page of image data is divided into band data and processed sequentially.

[0040] In step S503, a barcode portion is detected by the barcode detection unit. Here, information indicating the position and size of the barcode contained in the image data is obtained. As will be described in detail later, if the barcode data is formed from a barcode font, the barcode information may be obtained during rendering in step S502, or the barcode may be detected from edge information after bitmapping. Alternatively, the barcode may be obtained by having the user specify the position of the barcode on the panel or on the host side.

[0041] In step S504, image processing is performed to convert the image data into a format that can be recorded by the printer 407. First, the image data output in step S503 is converted into image data that corresponds to the color reproduction gamut of the printer.

[0042] The image data input in step S501 is data that indicates color coordinates (R, G, B) in a color space coordinate system such as sRGB, which is the display color of the monitor. The input image data of 8 bits each of R, G, and B is converted into image data (R', G', B') in the color reproduction gamut of the printer using a known method such as matrix calculation processing or processing using a three-dimensional LUT.

[0043] Next, the 8-bit image data for each of R', G', and B' is converted into image data based on color signal data for the inks used in the printer 407. The printer 407 of this embodiment prints images using black (K), cyan (C), magenta (M), and yellow (Y) inks. Therefore, the image data for RGB signals is converted into image data consisting of 8-bit color signals for each of the K, C, M, and Y ink colors. This color conversion is also performed using a three-dimensional lookup table in combination with interpolation. Note that, as with the above, other conversion methods, such as matrix calculation processing, may also be used. Furthermore, the number of ink colors is not limited to four, K, C, M, and Y, and other color inks may also be used, such as light-density light cyan (Lc), light magenta (Lm), gray (Gy), transparent ink, and special color ink.

[0044] Next, a process is performed to adjust the number of dots to be printed on the recording medium by correcting the 8-bit image data for each color. While one dot is formed by applying one ink droplet to the recording medium, the relationship between the number of dots formed on the recording medium and the optical density expressed by that number of dots is generally not linear. Therefore, the number of dots to be applied is adjusted so that the optical density has a linear relationship to the number of dots. A one-dimensional lookup table (LUT) is used as a method for converting input data into output data in this adjustment process.

[0045] Next, the image data for each 8-bit, 256-value ink color is quantized to generate 1-bit binary data, either a "1" indicating printing or a "0" indicating non-printing. The output of the quantization process may be the number of ink droplets per unit area, and is not limited to 1-bit binary data consisting of a "1" for printing or a "0" for non-printing. Quantization to multi-value data of 2 or more bits is also possible. While error diffusion and dithering are well-known quantization methods, any method may be used.

[0046] Then, in step S505, an image is recorded based on the image data generated in step S504. At this time, the transport amount is adjusted based on the position and size of the barcode detected in step S503.

[0047] Here, the method for adjusting the conveyance amount in step S505 will be described in detail. In a printer that records an image on a recording medium using a so-called multi-pass recording method, the conditions for the recording operation are determined taking into consideration factors such as the performance of the recording head 303, the output image quality, and the print speed. For example, when using plain paper, productivity is often required, so so-called one-pass recording is adopted, in which image recording is completed in one recording scan for a unit area on the recording medium. Even in the case of one-pass recording, there is a known technique for increasing robustness against variations in conveyance accuracy by partially overlapping the area recorded in one recording scan with the area recorded in the next recording scan. However, the narrower the overlapping area (border), the less effective the increase in robustness becomes, and the wider it is, the more recording scans are required, reducing productivity.

[0048] 6 is a diagram showing print scans and their boundaries (borders) when printing an image including a barcode. Here, an example will be described in which a barcode 603 is printed on a print medium P using black ink, using only the black nozzle row 24 of the print head 303.

[0049] 6(a) is a schematic diagram of a barcode 603 being printed by two scans of the print head 303. Position 601 indicates the position of the print head 303 in the Y direction relative to the print medium during the first print scan. At this position 601, the print head 303 scans in the X direction, and ink is ejected from the black nozzle row 24 to print the upper part of the barcode 603.

[0050] After the first print scan, the print medium P is transported in the +Y direction. Position 602 indicates the position of the print head 303 in the Y direction relative to the print medium after transport. At this position 602, the print head 303 performs a second print scan, and the lower part of the barcode 603 is printed.

[0051] 6(b) is an enlarged view of the boundary (junction) between scans of a barcode 603 printed by two print scans at positions 601 and 602 of the print head 303, showing the impact state of applied ink droplets 604. In the figure, (x) shows a case where the print medium P is transported by an ideal amount between the first and second scans. Similarly, (y) shows a case where the transport amount is insufficient, and (z) shows a case where the transport amount is excessive.

[0052] Reference numeral 605 denotes a 600 dpi grid, in which each square is 1200 dpi and is arranged in a 2 pixel by 2 pixel grid. Here, two dots are formed in the 600 dpi grid. As mentioned above, the print head 303 has nozzles spaced at 1200 dpi intervals, and when ink is ejected from each nozzle during a print scan at position 601, dots are arranged as in grid 605. In reality, the ink bleeds and spreads widely on the print medium, making the color of the print medium P (paper white) invisible, but this figure shows a state in which ink bleed is suppressed.

[0053] In Figure 6(b), (x) represents the case where the transport distance between two print scans is ideal, with no error occurring, so the ink droplets land in the ideal positions, maintaining the quality of the barcode.

[0054] On the other hand, (y) shows a case where the transport amount is insufficient, and the dots formed by the print scan at position 601 and the dots formed by the print scan at position 602 overlap, causing ink droplets to concentrate at the joint. In this way, ink droplets are applied in a concentrated manner in a narrow area with a short time difference, causing the ink to bleed, resulting in thicker line widths in the barcode.

[0055] Also, (z) is the case where the transport amount is too large, resulting in a large gap between the dot formed by the print scan at position 601 and the dot formed at position 602, resulting in a shortage of ink droplets at the connecting portion. As a result, the color of the print medium (paper white) becomes visible, or the ink at both ends of the connecting portion bleeds, reducing the density of the connecting portion and narrowing the width of the bar.

[0056] In this way, when a barcode is recorded by multiple recording scans, there is a possibility that the width of the bars will not be constant due to errors in the transport amount.

[0057] Barcode optical reading devices (barcode readers) are available in both contact and non-contact types. A person holds the barcode reader close to the barcode, and the red light from the reading window illuminates the barcode, reading it. It is highly likely that the reading operation will be performed by pointing the barcode reader at the center of the bar.

[0058] FIG. 7 is a diagram illustrating an example of a CCD scanning barcode reader. In the CCD scanning method, a barcode 702 is uniformly illuminated with light from a red LED 701. The image of the barcode is refracted by a mirror 703 and projected onto a CCD sensor 705 by a lens 704. The CCD sensor 705 is a line sensor with 1,000 to 2,000 optical sensors lined up in a row, which output electrical signals in order from one end to the other. The bar areas of the barcode reflect less light, so the electrical signal output is small. On the other hand, the space areas reflect more light, so a large electrical signal is output.

[0059] Since the light from the red LED 701 only illuminates a portion of the barcode, if the width of the bar in the illuminated area is not the intended width, accurate reading cannot be achieved. There are several evaluation values known for barcode reader performance in reading barcodes, but the above-mentioned issue affects modulation and defects.

[0060] Modulation is the ratio of the minimum edge contrast to the symbol contrast. The greater the difference in reflectance between a space and its adjacent bars, the easier it is to read the barcode.

[0061] A defect is a chip (void) in a bar or a stain (spot) in a space. When a valley occurs that causes unevenness in a space relative to a peak that represents the maximum reflectance, the smaller the difference between the maximum reflectance of the peak and the reflectance of the valley, the easier it is to read the barcode. In the case of a bar, the peak and valley of the space are opposite.

[0062] In this way, the quality of the bars is reduced, which affects the readability of the barcode. To address this issue, this embodiment adjusts the amount of transport of the recording medium so that the joints during printing and scanning are positioned closer to the edge of the barcode rather than the center, thereby suppressing the reduction in quality of the bars in areas that are more likely to be read.

[0063] Here, we will explain the printing operation when the Y-direction length of the barcode to be printed (the length of the long side of the bar, also called the height of the barcode) is longer than the length of the nozzle row of the print head 303 and shorter than twice the length of the nozzle row.

[0064] 8(a) shows a case where the length of the bars of barcode 803 is approximately 1.5 times the length of the nozzle array of print head 303 (hereinafter referred to as the nozzle length), and the barcode is printed by two print scans at positions 801 and 802. The dashed lines indicate the positions of the boundaries of the areas printed by each print scan. The boundaries of the print scans are located near the centers of the multiple bars that form barcode 803.

[0065] If the barcode length is longer than the nozzle length, it will be printed using multiple print scans, but as mentioned above, the quality of the bar may be reduced at the print scan boundaries. For this reason, it is better to have as few borders as possible. However, if the number of borders is reduced to one using two print scans as shown in Figure 8(a), the border will be located near the center of the barcode, which may affect the reading results.

[0066] 8(b) shows the case where a barcode 803, whose bar length is approximately 1.5 times the nozzle length of the print head 303, is printed using three print scans from positions 804 to 806. Similarly, the dashed lines indicate the positions of the boundaries.

[0067] By printing the barcode in three printing scans, the second printing scan at position 805 uses all the nozzles of print head 303 to print. That is, because the area including the center of the barcode is printed by the printing scan at position 805, the position of the boundary can be moved away from the center of the barcode.

[0068] In this way, when the height of the barcode (the length of the long side of the bar) is longer than the nozzle length but shorter than twice the nozzle length, the barcode is recorded using three recording scans, preventing the boundary between the recording scans from being located at the center of the bar in the longitudinal direction. This prevents a decrease in the recording quality of the bar near the center, where light is likely to be irradiated when the barcode is read. This is particularly effective when the direction in which the long sides of the bars forming the barcode extend coincides with the transport direction of the recording medium. Even if they do not coincide, the closer the angle, the greater the effect.

[0069] 9 is a flowchart showing the recording control of this embodiment. In step S901, image data of an image including a barcode is input, and in step S902, the barcode portion in the input image data is detected.

[0070] In step S903, the length of the detected barcode in the transport direction of the recording medium (barcode length B_Len) and the barcode start position Y on the recording medium are obtained. For the barcode start position, it is sufficient to obtain at least the Y coordinate in the transport direction. The end position may be calculated by adding the barcode length B_Len to the barcode start position B_Ys, or it may be obtained from the image data. Alternatively, the barcode start position B_Ys and end position B_Ye may be obtained and the barcode length B_Len may be calculated.

[0071] In step S904, the nozzle length N_Len, which is a default value stored in memory, is acquired. Then, in step S905, B_Len and N_Len are compared to determine whether the following formula 1 is satisfied.

[0072] N_Len×2 > B_Len > N_Len (Formula 1) In step S905, it is determined using the above formula 1 whether the barcode length B_Len is longer than the nozzle length N_Len and shorter than twice the nozzle length N_Len. If formula 1 is satisfied, the conveyance amount is adjusted so that the barcode portion is recorded in three recording scans. If formula 1 is not satisfied, the conveyance amount of the recording medium is adjusted so that the number of recording scans required to record the barcode portion is minimized.

[0073] If formula 1 is not satisfied, it means that N_Len is longer than the barcode length B_Len, or the barcode length B_Len is N_Len x 2 or more. The recording operation in these cases will be explained in the embodiments described later.

[0074] FIG. 10 is a diagram illustrating a method for adjusting the conveyance amount so that printing is performed in three printing scans when it is determined in step S905 that Expression 1 is satisfied.

[0075] 10(a) and (b) show band data for one page of page data, with the area printed in one print scan separated by dashed lines. In the example shown in this figure, the page data is printed in nine print scans.

[0076] When image processing is performed within the recording device as shown in Figure 10(a), the barcode portion is recorded in two recording scans, the seventh and eighth recording scans. However, as mentioned above, the transport amount must be adjusted to avoid the boundary between the recording scans being located near the center of the long side of the bar. Figure 10(b) shows the band data after adjustment, in which the barcode portion is recorded in three recording scans. In this example, the eighth recording scan is the second of the three recording scans that record the barcode portion. During this eighth recording scan, the center position B_Yc of the long side of the bar in the barcode portion is calculated or acquired. Then, the recording scan start position is calculated so that the center position B_Yc is not recorded by the end nozzles of the nozzles used for recording.

[0077] The calculation method is explained below using example values. The coordinate position on the upstream side of the print medium in the transport direction (top of the diagram) is set to 0. If the transport amount per scan and the nozzle length N_len are 30, the start position of the second print scan is 30, and the start position of the seventh print scan is 180.

[0078] Here, the barcode length B_Len is 50, the barcode start position B_Ys is 190, and the barcode end position B_Ye is 240. In this case, the barcode center position B_Yc is 215. Therefore, in order for the center position of the nozzle length 30 to coincide with the coordinate 215, which is the center position of the barcode, it is necessary to control the coordinate of the start position of the eighth printing scan to be 200. Figure 10(b) shows the state after adjustment.

[0079] To set the coordinate of the start position of the eighth printing scan to 200, it is necessary to change the start positions of the printing scans prior to the eighth. If the coordinate of the start position of the sixth printing scan is left unchanged at 150 from the state in FIG. 10(a), the coordinate of the start position of the seventh printing scan will be 170. In that case, the band data for the sixth printing scan will be as shown in FIG. 10(c).

[0080] Figure 10(c) shows band data with a height of 30, with image data held in the top 20 area, but no image data held in the bottom 10 area, with white data added instead of being printed. This allows the height of the band data to be kept constant, and adjustments can be made by changing the carry amount without imposing a load on image processing. Note that the sixth printing scan can be performed in the same manner as in Figure 10(a), and the same processing can be performed with the coordinates of the start position of the seventh printing scan set to 180.

[0081] On the other hand, when the height of the band data is made variable, it is possible to adjust the transport amount and transport start position by making them the same as the height of the band data, without adding white data where no image is printed.

[0082] The transport amount can be adjusted by changing the transport amount sent to the paper feed / discharge motor control unit 304. Furthermore, if there is no image in the image data before the band data containing the barcode portion, white data, which is data that is not printed, can be added, or the paper can be transported to the start position of the first printing scan of the three printing scans that print the barcode portion.

[0083] In this way, when the relationship between the nozzle length N_Len and the barcode length B_Len satisfies the condition of the above formula 1, it is possible to shift the boundary of the print scan from the center of the barcode by adjusting the carry amount so that printing is performed in three print scans. As a result, it is possible to suppress the effects on reading caused by degradation of barcode printing quality due to print medium transport error.

[0084] In this embodiment, the length in the Y direction of the area printed in one print scan is the nozzle length. In other words, all nozzles arranged in the nozzle row are used in one print scan, but the present invention is not limited to this. The range of nozzles used in one print scan may be a range shorter than the nozzle length. In that case, the amount of print medium transport between print scans can be adjusted to match the range of nozzles used, and N_Len, which is compared in equation 1 above, can also be adjusted to a length corresponding to the range of nozzles used.

[0085] (Modification of the first embodiment) In the first embodiment, a method was described in which adjustments were made so that the barcode portion was printed in three printing scans when the relationship between the nozzle length N_Len and the barcode length B_Len satisfied the condition of Formula 1. In this modified example, a method of printing in two printing scans will be described. Even when printing a barcode in two printing scans, the boundary of the printing scans can be shifted from the center position of the barcode portion.

[0086] As in the first embodiment, the coordinates of the center position B_Yc of the barcode portion are calculated based on the position information of the barcode. In a print scan that includes this center position B_Yc, if the nozzle length N_Len falls within the range of the barcode, it is possible to prevent the boundary from hitting the center position of the barcode.

[0087] 11 is a diagram showing an adjustment method for printing a barcode 1103 in two printing scans when the nozzle length N_Len is 30 and the barcode height B_Len is 40. In the Y direction, which is the conveyance direction of the printing medium, the center position B_Yc of the barcode 1103 is included within the range of the first printing scan 1101, and the nozzle length N_Len is entirely within the range of the barcode 1103 in the Y direction. In other words, the start position of the first printing scan of the printing scans that prints the barcode 1103 is the same as the start position B_Ys of the barcode portion.

[0088] Alternatively, the center position B_Yc of the barcode may be recorded during the second print scan 1102. In this case, the coordinates of the bottom edge position B_Ye of the barcode portion should be the coordinates of the start position of the second print scan plus the nozzle length N_Len. This prevents the boundary between print scans from coming near the center of the barcode portion. The method for adjusting the carry amount is the same as in the first embodiment.

[0089] Even when recording a barcode portion in two recording scans in this way, it is possible to move the connecting portion between the recording scans away from the center position of the barcode, thereby preventing a decrease in the barcode recording quality.

[0090] (Second embodiment) In the second embodiment, a case where the condition of the formula 1 in the first embodiment is not satisfied will be described. In other words, the cases where the formula 1 [N_Len×2>B_Len>N_Len] is not satisfied include the following two cases. When the barcode height is shorter than the nozzle length N_Len > B_Len (Equation 2) - When the barcode height is longer than twice the nozzle length N_Len × 2 < B_Len (Formula 3) First, if formula 2 is satisfied, that is, if the barcode height is shorter than the nozzle length, it is possible to print the barcode in a single printing scan. If printing can be done in a single printing scan, it is possible to print the barcode without generating any seams. Therefore, by adjusting the transport amount so that the number of printing scans required to print the barcode is the minimum, one, it is possible to prevent a decrease in the printing quality of the barcode.

[0091] Next, we will explain the case where Equation 3 is satisfied, that is, the case where the barcode height is longer than twice the nozzle length. For example, suppose the barcode height is 2.5 times the nozzle length. FIG. 12 shows an example where the carry amount is not adjusted, and a barcode portion 1203 is printed using four printing scans 1201 to 1204. In this case, three printing scan joints occur within the barcode portion. On the other hand, by printing the barcode portion 1203, which is 2.5 times the nozzle length, using the minimum number of printing scans, three, the number of joints can be reduced to two. This makes it possible to avoid printing near the center of the barcode portion at the end of the nozzle length. The method of adjusting the carry amount is the same as in the first embodiment.

[0092] (Third embodiment) In the first and second embodiments described above, a method was described in which the transport of the recording medium was adjusted to move the connecting portion of the print scan away from the center of the barcode by preventing the center position of the barcode from being printed at the end of the nozzle length. In this embodiment, a method will be described in which the same effect is achieved by adjusting the position of the barcode in the image data, without adjusting the transport amount of the recording medium.

[0093] 9, the process up to the step S905 where a determination is made based on the barcode height and nozzle length is the same as in the previously described embodiment. If the determination result shows that the condition is met, the coordinates of the barcode position within the image are adjusted so that the barcode portion is recorded in three recording scans, and if the condition is not met, the barcode position within the image is adjusted so that the minimum number of recording scans is required.

[0094] The processing when the condition of Expression 1 is satisfied will be explained using Figure 13. In Figure 13(a), the transport amount per scan and the nozzle length N_len are set to 30. The coordinates of the start position of the second print scan are set to 30, and the coordinates of the start position of the seventh print scan are set to 180. If the barcode B_Len is set to 50, the barcode start position B_Ys is set to 190, and the barcode end position B_Ye is set to 240, the coordinate of the barcode center position B_Yc is set to 215.

[0095] Because the center position of the barcode is located at the center of the band during the second of the three recording scans used to record the barcode, it is set to the center of the eighth recording scan, as shown in Figure 13(b). Since the coordinate of the center of the eighth recording scan is 225, the coordinate of the barcode center position B_Yc should be set to 225. To achieve this, the position of the barcode portion in the image data is moved +10 in the Y direction. The seventh recording scan could be used as the second recording scan used to record the barcode, but this could result in overlapping with images located upstream of the barcode. Therefore, when moving the position of the barcode portion, it is preferable to determine the positions of the surrounding images and move them in a direction that prevents overlapping. This can be achieved by checking the presence or absence of images within the band data. Similarly, when processing when the conditions are not met, it is preferable to calculate the amount of movement of the barcode portion so that the number of transitions between recording scans is minimized.

[0096] Next, we will explain how to move an image. There are several ways to move an image, such as when rasterizing raster data, using rasterized BMP data (RGB data), or using quantized dot data. When moving an image during rasterization, the coordinate calculation position is calculated when issuing a drawing command, and the image can be moved by correcting the Y coordinate. When using BMP data or quantized data, the image of the barcode section is stored in memory once, and then the pixels at the barcode section position are changed to white pixels, and the barcode data is copied to the pixel data of the destination.

[0097] In this way, by moving the image of the barcode portion taking into consideration the transport joints, the number of joints, which are the boundaries of the recording scans within the barcode, can be reduced and moved away from the center of the barcode portion. [Explanation of symbols]

[0098] 301 Recording device main control section 303 Recording head 304 Paper feed / eject motor control unit 308 Image processing device main control unit

Claims

1. a conveying means for conveying the recording medium in a first direction; a recording means including a nozzle row in which a plurality of nozzles for ejecting ink are arranged along the first direction, and which records an image on the recording medium transported by the transport means by scanning in a second direction intersecting the first direction; a control means for controlling the conveying means and the recording means to record an image on the recording medium by performing a conveying operation for conveying the recording medium and a recording operation by scanning the recording means based on image data of an image including a barcode portion formed by a plurality of bars; A recording device comprising: when the length in the first direction of the barcode portion recorded on the recording medium is longer than a first length, which is the length in the first direction of an area recorded in one scan by the recording means, and shorter than twice the first length, the control means controls the conveyance of the recording medium by the conveyance means so that the barcode portion is recorded in three scans by the recording means; A recording apparatus, wherein the amount of conveyance of the recording medium performed by the conveying means between two scans of the recording means is the first length.

2. 2. The recording device according to claim 1, wherein the control means further comprises a determination means for determining whether the length in the first direction of the barcode portion recorded on the recording medium satisfies the condition that the length is longer than the first length and shorter than twice the first length.

3. 3. The printing apparatus according to claim 1, wherein the first length is a nozzle length over which a plurality of nozzles are arranged in the nozzle row.

4. 4. The recording apparatus according to claim 1, wherein the recording means performs reciprocal scanning in the second direction.

5. 5. A recording device according to claim 1, wherein the three scans for recording the barcode portion are scans in the forward direction in the first direction, and the control means performs scans in the backward direction without ejecting ink between the three scans for recording the barcode portion.

6. 6. The recording apparatus according to claim 1, wherein the center position of the barcode portion in the first direction is recorded in the second scan of the three scans for recording the barcode portion.

7. a conveying means for conveying the recording medium in a first direction; a recording means including a nozzle row in which a plurality of nozzles for ejecting ink are arranged along the first direction, and which records an image on the recording medium transported by the transport means by scanning in a second direction intersecting the first direction; A control method for a recording device comprising: the conveying means and the recording means are controlled so as to record an image on the recording medium by performing a conveying operation of conveying the recording medium and a recording operation by scanning the recording means based on image data of an image including a barcode portion formed by a plurality of bars, when the length in the first direction of the barcode portion recorded on the recording medium is longer than a first length, which is the length in the first direction of an area recorded in one scan by the recording means, and shorter than twice the first length, conveyance of the recording medium by the conveying means is controlled so that the barcode portion is recorded in three scans by the recording means; A control method, wherein the amount of transport of the recording medium performed by the transport means between two scans of the recording means is the first length.

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