JP2008062516A - Printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing device enhancing the convenience of a user by visually suppressing printing error to the minimum without wasting ink or sheets. <P>SOLUTION: The printing device has a printing head having nozzles for discharging the ink and controlling the discharge of the ink based on printing data while scanning on the printing sheet, an image area detecting section 202 analyzing the printing data and detecting the image area of the printing data, a printing error detecting section 203 detecting the printing error during printing the image area, and a printing error correcting means (a non discharge interpolating section 205 and a blur correction processing section 206) correcting the printing error detected by the printing error detecting section 203, the printing is carried out correction of the printing data by the printing error correcting means after detecting the printing error when detecting the printing error during printing the image area of the printing data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention, for example, uses at least one print head such as an inkjet printing apparatus to eject a recording agent such as ink of at least one color from each print head, and forms an image on a print medium by a set of dots of the recording agent. And a control method thereof.

  Inkjet printers are widely used as color printers because they are non-impact, have low noise, and are easy to color.

  A color inkjet printing apparatus is a number corresponding to the number of printing colors at a predetermined pitch along the scanning direction on a carriage that scans and moves along a guide shaft installed in parallel with a sheet feeding roller that conveys a sheet as a printing medium. The print head is mounted, and heat energy is applied to the ink, and each color (for example, cyan, yellow, magenta, black) is ejected from each print head to form a color image on the print sheet. Yes.

  Since a printing sheet used in this type of color ink jet printing apparatus is required to have a large amount of ink and to absorb it quickly, coated paper having an ink absorbing layer is generally used. However, as ink jet printing apparatuses become widespread, it has become necessary to print not only on coated paper but also on plain paper.

  When storing on plain paper or the like with a conventional ink jet printing apparatus, plain paper has a small ink absorption capacity and slow absorption speed, so that ink overflows on the print medium, particularly in the image area, and bleeding is likely to occur. The image quality deteriorated and it was difficult to obtain a high-quality image.

  As a method for solving the above problems, a method disclosed in Japanese Patent Application Laid-Open No. 08-300509 is known. In this publication, a user prints a pattern for detecting a blur amount before printing, reads the printed pattern with a scanner, and executes printing after determining parameters for correcting the blur amount.

  On the other hand, this recording method performs recording by ejecting ink onto a recording sheet in accordance with a recording signal, and is widely used as a quiet recording method at a low running cost. By using the recording head in which the nozzles are arranged in a straight line in the sub-scanning direction, the recording head scans the recording paper once, thereby recording with a width corresponding to the number of nozzles. Therefore, if even one nozzle of the recording head is clogged, deterioration of image quality is unavoidable due to non-ejection of ink droplets. Especially in high density image areas, it becomes “white streaks” and the image quality is greatly deteriorated. It was unavoidable.

When such an undischarge nozzle is detected, the user is prompted to replace the print head, and the image around the undischarge nozzle is corrected to a higher density than usual to prevent image deterioration. (For example, JP-A-5-220977). This is a technique generally called head shading.In many cases, a specific chart (pattern) is printed by a printing device to be corrected, read by a scanner, and a value to be corrected is calculated based on the data. Then, the output result is corrected by calculating the correction amount as a table to the input image.
Japanese Patent Laid-Open No. 08-300639 Japanese Patent Laid-Open No. 5-220977

  However, the above prior art has the following problems.

  That is, according to Japanese Patent Application Laid-Open No. 08-300509 and Japanese Patent Application Laid-Open No. 5-220977, in order to detect printing failure factors such as non-discharge and blurring before the target print data is printed, A pattern was printed, and a detection pattern was read by a scanner or the like to detect and correct the cause of printing failure. In other words, regardless of the presence or absence of a printing failure factor, the detection pattern for the printing failure factor is printed before the target print data is printed, so paper and ink for the detection pattern and adjustment pattern are wasted. .

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printing apparatus that visually minimizes printing defects and improves user convenience without wasting ink and paper.

  In order to achieve the above object, the present invention provides a print head that includes a nozzle for ejecting ink and that controls ejection of ink based on print data while scanning the print paper, and analyzes the print data, and the print data An image area detecting means for detecting the image area, a printing defect detecting means for detecting a printing defect during printing of the image area, and a printing defect correcting means for correcting the printing defect detected by the printing defect detecting means. When the printing defect is detected during printing of the image area of the print data, the printing defect is detected by the printing defect correction means after the printing defect is detected, and printing is performed. It is characterized by performing.

  In order to achieve the above object, the print defect detection means includes a scanner unit provided in the print head, and the print unit ejected based on the print data by the scanner unit provided in the print head. It is desirable to detect the print defect by reading the result and comparing the print data with data obtained by reading the print result discharged based on the print data.

  Further, in order to achieve the above object, the printing failure detection means detects a discharge failure nozzle, and detects the discharge failure nozzle while printing the image area of the print data. It is desirable to perform printing by correcting the print data or print control so that the discharge failure correction means interpolates the discharge failure nozzle.

  In order to achieve the above object, the print defect detection means detects ink bleed, and if the ink bleed is detected while printing the image area of the print data, the ink bleed is detected. It is preferable that printing is performed by correcting the print data or the print control so that the printing defect correction means reduces the ink bleeding.

  In order to achieve the above object, a print head provided with a nozzle for ejecting ink and controlling the ejection of ink based on print data while scanning on the printing paper, and analyzing the print data, the image of the print data An image area detecting means for detecting an area; a print defect detecting means for detecting a printing defect during printing of the image area; and whether or not to stop printing of the print data and stop printing of the print data It is preferable that a selection unit is provided to select whether or not to stop printing of the print data and stop printing of the print data when the printing failure is detected during printing of the image area of the print data.

  According to the present invention, it is not necessary to print a detection and adjustment pattern for detecting a printing defect factor such as non-discharge or blurring before executing a target print. There is no need to waste ink.

  Further, according to the present invention, when a printing failure such as undischarge or bleeding is detected during printing, the printing failure can be visually minimized by correcting the printing failure and continuing printing.

  Further, according to the present invention, when printing failure such as undischarge or bleeding is detected during printing, it is not necessary to consume useless ink by stopping printing.

  Hereinafter, an embodiment in which printing is performed by a printing apparatus 100 with a print defect correction function according to the present invention from a client PC 1301 (hereinafter referred to as a PC) connected via a network will be described in detail with reference to the drawings.

  FIG. 13 is an overview of this embodiment.

  As shown in FIG. 13, the PC 1301 and the printing apparatus 100 with a print defect correction function are connected via a network, and the user can perform printing by operating the printing apparatus 100 with the print defect correction function from the PC 1301. The printing apparatus 100 with the print defect correction function receives a print command directly from a portable device such as a digital camera or PDA that supports the network, and the image processing unit 107 and the printing unit inside the print defect correction function printing apparatus 100 It is also possible to generate print data by the image data creation means 303 and print it.

  Next, the internal configuration of the printing apparatus 100 with the print defect correction function will be described. FIG. 1 shows an internal configuration diagram of a printing apparatus 100 with a defective printing correction function according to the present invention.

  As shown in FIG. 1, the printing apparatus 100 with a print defect correction function includes an input unit 101, a work memory 104, a program storage memory 103, a display unit 102, a network I / F unit 105, an image processing unit 107, a print defect. A correction processing unit 108, a controller 109, a printer unit 112, a power source 111, and a CPU 106 for controlling each block are configured. The printer unit 112 includes various motors 115, various motor driving units 110, a print head 114, and a print head driving unit 113.

  The input unit 101 is a key input unit provided in a general printing apparatus, such as turning on / off the main power of the printing apparatus 100 with the print defect correction function 100 and canceling a job.

  The display unit 102 is configured as a display device having a screen such as a liquid crystal display element, and displays various setting states, print statuses, error / warning messages, and the like.

  The image processing unit 107 rotates the image and stores it in a band buffer memory, changes the image size to a size suitable for the size of the printing paper, converts RGB data to YMC data for printing, and binarization for converting to printing data Perform processing.

  As shown in FIG. 3, the program storage memory 103 includes an undischarge nozzle interpolation mask data generation unit 302 according to the present invention in addition to the control program 300, various application programs 301, the printing image data generation unit 303, and the utility program 304. Storing. Note that the printing image data creation means 303 has three components including a rasterizer, a color correction module, and a halftone module, which have the same configuration as a program for printing image data creation processing in a personal computer or the like as software processing of the image processing unit 107. Are provided as basic means for obtaining binary data necessary for drawing, and YUV data is printed on CMYK floors for printing K (black), C (cyan), M (magenta), and Y (yellow). Convert to key image data.

  As shown in FIG. 4, the work memory 104 has a frame memory 400, a print data buffer 401, a spare area 402, a program area 403, and the like. In FIG. 4, the frame memory 400 is used as a display memory for menu display of the display unit 102. The print data buffer 401 is used for temporarily storing print data during printing. The spare area 402 is an empty area, and the size of the area varies depending on the size of the program being executed. The program area 403 stores the control program 300 read from the program storage memory 103 and the program activated at that time, and is executed under the control of the CPU.

  The network I / F unit 105 is an interface for connecting data and command signals to a personal computer (PC) 1301 or a digital camera or PDA that can be connected to the network by connecting to the network using a LAN cable.

  The print defect correction processing unit 108 has an important function in the present invention and will be described in detail later. The print data generated inside the printing apparatus 100 with the print defect correction function, the actually printed characters, and images are scanned by the scanner unit. It has a function of detecting a printing defect by comparing with the read data (hereinafter referred to as scan data) and correcting the printing defect.

  The controller 109 controls the operation of the entire printer unit 112. When receiving the printing data (and control data), the controller 109 sends a control signal to the printer unit 112 to control the print head driving unit 113 and the motor driving unit 110 to perform drawing and paper feeding so that the print image is printed. Get.

  The CPU 106 is connected to the above-described circuits and the like via a bus line, and controls the entire printing apparatus 100 with the print defect correction function by a control program 300 stored in the program storage memory 103.

  Next, the print defect correction processing unit 108 that plays an important role in the present invention will be described in detail. FIG. 2 shows an internal configuration of the printing failure correction processing unit 108 of the printing apparatus 100 with printing failure correction function according to the present invention. As shown in FIG. 2, the printing failure correction processing unit 108 of the printing device 100 with the printing failure correction function includes a scanner unit 200, a printing paper detection unit 201, an image area detection unit 202, a printing failure detection unit 203, undischarge interpolation. A processing unit 205, a blur correction processing unit 206, a discharge failure nozzle interpolation mask storage unit 207, and a blur correction mask storage unit 208 are connected to the CPU 106 via a bus.

  As shown in FIG. 6, the scanner unit 200 is provided adjacent to the print head 114 of the printing apparatus 100 with the print defect correction function. After the print head 114 of the printing apparatus 100 with the print defect correcting function 100 prints one line, the print information of the previous line can be read during printing of the next line. It is in the rear position.

  The print paper detection unit 201 detects the paper type set by the user and stores it during printing.

  The image area detection unit 202 analyzes the print data and detects an image area.

  Although described in detail later, the print defect detection unit 203 detects ink discharge failure and blurring by comparing print data with data read by the scanner unit 200.

  The non-discharge interpolation processing unit 205 generates mask data so as to interpolate the non-discharge nozzles when non-discharge is detected by the print defect detection unit 203.

  The discharge failure nozzle interpolation mask storage unit 207 stores discharge failure nozzle interpolation mask data created by the discharge failure nozzle interpolation mask data generation unit 302.

  The bleed correction processing unit 206 reads out a bleed correction mask corresponding to the bleed amount from the bleed correction mask storage unit 208 when the print defect detection unit 203 detects ink bleed, masks the print data, and discharges the ink. Limit the amount.

  The blur correction mask storage unit 208 stores correction mask data 503 and 504 corresponding to the amount of blur detected by the print defect detection unit 203 as shown in FIG. When the print defect detection unit 203 detects a bleed, a bleed correction mask is applied to the detected print data to limit the ink discharge amount in the print specific area. In this embodiment, as shown in FIG. 5, when the bleeding amount C detected by the print defect detection unit 203 is X ≦ C ≦ Y, mask data 503 for reducing the ink discharge amount in the print specific region by 5%. When Y ≦ C, the ink discharge amount is limited using the mask data 504 that reduces the ink discharge amount in the print specific area by 10%.

  Next, a printing defect detection method in the present embodiment will be described in detail with reference to FIGS.

  FIG. 6 shows a scanning image of the print head 114 of the printing apparatus 100 with the print defect correction function. As shown in FIG. 6, the print head 114 of the printing apparatus 100 with the print defect correction function prints after the print head 114 prints one line of printing paper (after one line scan) and prints the next one line. A scanner unit 200 is provided behind the print head 114 in the paper discharge direction so that print information for one line before the previous line can be read.

  Further, the operation of the carriage 112 in the forward path and the backward path will be described with reference to FIG. In the forward path, first, the forward print area 601 is printed, and at the same time, the print information in the forward scan area 600 is read. Next, the carriage 112 on which the print head 114 and the scanner unit 200 are mounted relatively moves in the paper discharge direction by the print head 114, and at the same time performs printing in the print area 602 of the return path area, and at the same time, the return path scan area 601, that is, the forward path printing. The printing information in the area 601 is read, and the next line (outward) printing is started.

  Next, a method for detecting nozzle discharge failure will be described with reference to FIG.

  FIG. 7 shows data (hereinafter referred to as scan data) read by the scanner unit after actually printing the print data in a certain area 603 during the printing operation and the print data (FIG. 7A) (FIG. 7B). ) Is shown.

  The undischarge nozzle detection method of the printing apparatus 100 with the print defect correction function is based on actual print data (Fig. 7 (a)) (ink ejection information) and scan data obtained by reading an actual print image (Fig. 7 (b)). It is detected by comparison with. The scan data (FIG. 7 (b)) read by the scanner unit 200 with respect to the print data (FIG. 7 (a)) of the print head 114 having 64 nozzles as shown in FIG. 7 (a) is shown in FIG. In the case of b), that is, when the information of the position 704 of the third nozzle does not exist for one line, it is determined that the third nozzle of the print head 114 has failed. When the non-discharge failure is detected, the printing apparatus 100 with the print failure correction function generates mask data so as to interpolate the non-discharge nozzles by the non-discharge nozzle interpolation mask data generation unit 302, corrects the print data, and prints.

  Next, a method for detecting the amount of ink bleeding will be described with reference to FIG.

  FIG. 8 shows the print data (FIG. 8 (a)) of a certain area 603 during the printing operation and the scan data (FIG. 8 (b)) read by the scanner unit 200 after actually printing the print data. Yes.

  The ink bleed amount detection method of the printing apparatus 100 with the print defect correction function includes the actual print data (Fig. 8 (a)) and the scan data (Fig. 8 (b)) read by the scanner after actual printing. It is detected by comparison. Further, how ink blots will be described in detail with reference to FIG. FIG. 9 schematically shows the fixing state 901 of the normal ink 900 and the case where the ink 902 is blurred. When the ink 900 that has landed on the paper oozes on the paper surface, when three dots of ink 902 are ejected to the position as shown in FIG. 9B, the ink penetrates into the adjacent dots and is visually adjacent. This is the same as when the ink 902 is ejected to the dot area 904. If the ink 902 oozes on the paper surface, particularly in an image area, the ink 902 mixes with other inks, causing deterioration of the printed image.

  In the present embodiment, a method for detecting the amount of bleeding when ink permeates adjacent dots as shown in FIG. 9B will be described.

  The scan data (FIG. 8 (b)) read by the scanner unit 200 with respect to the print data (FIG. 8 (a)) of the print head 114 having 64 nozzles as shown in FIG. 8 (a) is shown in FIG. In the case of (b), the portion indicated by the broken-line circle 802 shown in FIG. 8 (b) is the scanner unit even though there is actually no print data as shown in FIG. 8 (a). 200 is read in the same manner as when ink is ejected. The detection of the bleeding amount of the printing apparatus 100 with the print defect correction function is performed by counting the portion indicated by the broken-line circle 802 in FIG. 8B and detecting the bleeding amount according to the counted number. When the count number exceeds a certain value, the printing defect detection unit 108 of the printing apparatus 100 with the printing defect correction function determines that bleeding has occurred, and the count number (bleeding amount C) from the bleeding correction mask storage unit 208. The blur correction masks 503 and 504 corresponding to the above are read out, and the mask is applied to the print data (FIG. 8A) to limit the ink discharge amount.

  Next, the printing operation of the printing apparatus 100 with the print defect correction function will be described in detail with reference to FIGS.

  FIG. 10 shows a print execution flow of the printing apparatus 100 with the print defect correction function.

  The printing apparatus 100 with the print defect correction function receives a print execution command and print data according to a user's print execution instruction (S1001), and starts a printing operation (S1002). When the printing apparatus 100 with the print defect correction function detects an image area during printing (S1003), the information printed by the scanner unit 200 provided in the print head 114 is read and compared with print data to detect a print defect. (S1005). When a printing failure is detected in step S1005, the printing apparatus 100 with the printing failure correction function performs a predetermined printing failure process (S1006).

  FIG. 11 shows processing when ink ejection failure is detected in step S1005 of FIG.

  When the printing device 100 with the print defect correction function detects non-discharge during printing, the printing operation is temporarily stopped (S1101), a warning is given that ink non-discharge has been detected (S1102), and the current printing is continued. It is determined whether or not to cancel (S1103). When the user selects to cancel printing in step S1103, the printing apparatus 100 with the print defect correction function immediately stops printing (S1104). When the user selects to continue the current printing in step S1103, the printing apparatus 100 with the print defect correction function performs masking so that the undischarge nozzle interpolation mask data generation unit 302 interpolates the detected undischarge nozzle. Data is generated (S1105), and the subsequent printing is continued using the undischarge nozzle interpolation mask data (S1107).

  FIG. 12 shows processing when ink bleeding is detected in step S1005 of FIG.

  When the printing apparatus 100 with the print defect correction function detects ink bleeding during printing, the printing operation is temporarily stopped (S1201), a warning is given that ink bleeding has been detected, the set paper type and A confirmation message is displayed as to whether the paper set in the printing apparatus with the print defect correction function is correct (S1202), and it is determined whether to continue or cancel the current printing (S1203). When the user selects to cancel printing in step S1203, the printing apparatus 100 with the print defect correction function immediately stops printing (S1204). When the user selects to continue the current printing in step S1203, the printing apparatus 100 with the print defect correction function selects the blur correction masks 503 and 504 according to the blur amount (S1206), and the blur correction mask is added to the print data. The printing operation is continued over 503 and 504 (S1208).

[Other embodiments]
In the above embodiment, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and it goes without saying that various modified embodiments are possible.

  The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. A medium such as a storage medium storing software program codes for realizing the functions of the above-described embodiments is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the medium in the storage medium or the like. It goes without saying that the present invention can also be achieved by reading and executing the program code.

  In this case, the program code itself read from the medium such as a storage medium realizes the functions of the above-described embodiments, and the medium such as the storage medium storing the program code constitutes the present invention. . As a medium such as a storage medium for supplying the program code, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM Alternatively, download via a network can be used.

  Further, by executing the program code read out by the computer, not only the functions of the above-described embodiments are realized, but also the OS running on the computer based on the instruction of the program code performs the actual processing. Needless to say, the present invention includes a case where the function of the above-described embodiment is realized by performing part or all of the processing.

  Furthermore, after the program code read from a medium such as a storage medium is written in a memory provided in a function expansion board inserted in the computer or a function expansion unit connected to the computer, based on the instruction of the program code, Needless to say, the present invention includes a case where the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

1 is an internal configuration diagram of a printing apparatus with a print defect correction processing function according to an embodiment of the present invention. FIG. It is an internal block diagram of the printing defect correction process part which concerns on embodiment of this invention. It is a memory map of the program storage memory which concerns on embodiment of this invention. It is a memory map of the working memory which concerns on embodiment of this invention. It is a figure which shows the blurring correction mask storage part which concerns on embodiment of this invention. It is a figure which shows the scanning image of the print head which concerns on embodiment of this invention. It is explanatory drawing of the non-discharge detection method of the nozzle which concerns on embodiment of this invention. It is explanatory drawing of the detection method of the amount of bleeding which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the bleeding state of the ink which concerns on embodiment of this invention. It is a figure for demonstrating the printing operation | movement flow of the printing apparatus with this printing defect correction process function which concerns on embodiment of this invention. It is a figure for demonstrating the operation | movement flow at the time of undischarge detection of the printing apparatus with this printing defect correction process function which concerns on embodiment of this invention. It is a figure for demonstrating the operation | movement flow at the time of the blur detection of the printing apparatus with this printing defect correction process function which concerns on embodiment of this invention. 1 is an overview of an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printing apparatus with printing defect correction function 101 Input means 102 Display part 103 Program storage memory 104 Work memory 105 Metalwork I / F part 106 CPU
DESCRIPTION OF SYMBOLS 107 Image processing part 108 Print defect correction process part 109 Controller 110 Motor drive part 111 Power supply 112 Printer unit 113 Print head drive part 114 Print head 115 Various motors 200 Scanner part 201 Print paper detection part 202 Image area detection part 203 Print defect detection part 203 205 Undischarge Interpolation Processing Unit 206 Blur Correction Processing Unit 207 Undischarge Nozzle Interpolation Mask Storage Unit 208 Blur Correction Mask Storage Unit 600 Outward Scan Area 601 Outward Print Area (Return Path Scan Area)
602 Return path printing area 603 Printing area in a certain place 700 Position without ink ejection data 701 Position with ink ejection data 702 Position where ink was ejected 703 Position where ink was not ejected 704 Position where ink was not ejected 800 Ink ejection Position without data 801 Position with ink ejection data 802 Position where ink is blotted 803 Position where ink is ejected 900 Ink droplet 901 Normal ink fixing state 902 Ink droplet 903 Ink landing position 904 Position where ink is blotted

Claims (5)

  A print head that includes a nozzle for ejecting ink and that controls ejection of ink based on print data while scanning on a print sheet; and an image area detection unit that analyzes the print data and detects an image area of the print data; A printing failure detection means for detecting a printing failure during printing of the image area; and a printing failure correction means for correcting the printing failure detected by the printing failure detection means. When the printing failure is detected during printing, after the printing failure is detected, the printing failure is printed by correcting the printing data or printing control by the printing failure correction means.   The print defect detection means includes a scanner unit provided in the print head, reads a print result discharged based on the print data by the scanner unit provided in the print head, the print data, The printing apparatus according to claim 1, wherein the printing defect is detected by comparing data obtained by reading a printing result ejected based on the printing data.   The printing failure detection unit detects a discharge failure nozzle and detects the discharge failure nozzle while printing the image area of the print data. After the discharge failure nozzle is detected, the printing failure correction unit detects the discharge failure nozzle. 3. The printing apparatus according to claim 1, wherein printing is performed by correcting the print data or the print control so as to interpolate.   The printing defect detection unit detects ink bleeding, and detects the ink bleeding during printing the image area of the print data. After detecting the ink bleeding, the printing defect correction unit detects the ink bleeding. 3. The printing apparatus according to claim 1, wherein printing is performed by correcting the print data or print control so as to reduce bleeding.   A print head that includes a nozzle for ejecting ink and that controls ejection of ink based on print data while scanning on a print sheet; and an image area detection unit that analyzes the print data and detects an image area of the print data; A printing failure detection unit that detects printing failure during printing of the image area; and a selection unit that determines whether printing of the printing data is stopped and printing of the printing data is stopped. 3. The printing apparatus according to claim 1, wherein when the printing defect is detected during printing of the image area, it is possible to select whether to stop printing of the printing data and to stop printing of the printing data. Printing device.

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