JP6285767B2 - Recording apparatus and inspection method - Google Patents

Description

  The present invention relates to a recording apparatus and an inspection method, and more particularly to a recording apparatus and an inspection method for recording on roll paper using, for example, a full line recording head according to an ink jet system.

  Conventionally, various printing inspection methods have been proposed in order to inspect printing defects of printed matter. For example, Patent Document 1 proposes a method in which an entire surface inspection of a printed material is performed for each small region, and a detailed inspection is performed only for the small region where an abnormality is recognized. As a result, it is possible to perform detailed inspection on the entire printed matter at high speed.

JP 2000-172844 A

  However, in recent years, the recording speed has further increased, and accordingly, a higher-speed inspection is required than the method according to the conventional example. In addition, in an ink jet printer, since the ink discharge amount is large in a portion where the density of image data is high, cockling is likely to occur on the recording paper, which may cause problems in the printing result. Corresponding inspection methods are also required.

  The present invention has been made in view of the above-described conventional example, and an object of the present invention is to provide a recording apparatus capable of inspecting printed matter at high speed and an inspection method executed by the apparatus.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording apparatus that performs recording by ejecting ink from a recording head having a recording width longer than the width of the recording medium to the recording medium, and buffer means for storing recording data used for recording by the recording head; The area of the conveying means for conveying the recording medium and the buffer means for storing the recording data is divided into a plurality of areas corresponding to the width direction of the recording medium and the conveying direction of the recording medium. And a counting unit that counts dots that cause ink ejection from the recording head for each of the plurality of regions based on recording data stored in each of the plurality of regions, and a conveyance direction of the recording medium by the conveyance unit, A reading unit provided on a downstream side of a recording position by the recording head and reading an image recorded by the recording head; A region having a high density in the image recorded by the recording head is identified based on the value counted by the recording unit, and the identified region is based on image data obtained from reading by the reading unit. Inspection means for inspecting an image recorded by the recording head.

  Another aspect of the present invention is an inspection method in a recording apparatus that performs recording by ejecting ink from a recording head having a recording width longer than the width of the recording medium onto a recording medium to be conveyed, A buffer area for storing recording data used for recording by the recording head is divided into a plurality of areas corresponding to the width direction of the recording medium and the conveyance direction of the recording medium, and stored in each of the divided areas. Based on the recorded data, each of the plurality of areas is recorded by the recording head based on a counting step for counting dots that cause ink ejection from the recording head and a value counted in the counting step. A region having a high density in the image to be recorded is specified, and the recording region is related to the recording medium transport direction with respect to the specified region. An inspection step of inspecting an image recorded by the recording head based on image data obtained from reading of a reading unit that is provided downstream of the recording position by the recording head and reads an image recorded by the recording head An inspection method characterized by the above is provided.

  Therefore, according to the present invention, the image data is divided into a plurality of regions corresponding to the recorded image, and whether or not the image is inspected for each region is determined from the number of dots that cause ink ejection obtained for each region. The image inspection can be performed on the area determined and determined to have a high density. Thereby, there is an effect that the printed matter can be inspected at high speed.

1 is a side cross-sectional view illustrating an outline of a configuration of a recording apparatus that is an example of an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a control circuit of the printer system illustrated in FIG. 1. 6 is a flowchart illustrating an inspection execution control process for the quality of a recorded image according to the first embodiment. FIG. 3 is a diagram schematically illustrating a state in which the inside of a print buffer is divided. It is a figure which shows an example of how to divide the area on the roll paper surface. It is a figure which shows the structure of the threshold value for the execution determination of an image inspection and the flag for execution determination of an image inspection stored in EEPROM. 10 is a flowchart illustrating an inspection execution control process for the quality of a recorded image according to a second embodiment.

  Hereinafter, an example of an embodiment of the present invention will be described more specifically and in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the already demonstrated part and duplication description is abbreviate | omitted.

  In this specification, “recording (printing)” (sometimes referred to as “printing”) is not limited to the case where significant information such as characters and graphics is formed, and is not significant. It also represents the case where an image, a pattern, a pattern, etc. are widely formed on a recording medium, or the medium is processed, regardless of whether it is manifested so that humans can perceive it visually. .

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. Therefore, by being applied on the recording medium, it is used for formation of images, patterns, patterns, etc., processing of the recording medium, or ink processing (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

   Further, the “recording element” (sometimes referred to as “nozzle”) is a general term for an ink discharge port, a liquid path communicating with this, and an element that generates energy used for ink discharge unless otherwise specified. Say it.

  FIG. 1 is a side sectional view showing a schematic configuration of an ink jet recording apparatus (hereinafter referred to as a recording apparatus) which is an example of an embodiment of the present invention.

  As shown in FIG. 1, this recording apparatus, for example, conveys a roll-shaped recording medium such as roll paper 2 by a conveying unit 3, and the black (K), cyan (C), Recording is performed by ejecting magenta (M) and yellow (Y) ink onto a recording medium. Each of the four recording heads 1K, 1C, 1M, and 1Y arranged in the roll paper conveyance direction is a full-line recording head whose recording width is longer than the width of the roll paper. These recording heads are driven by a control unit, which will be described later, and perform color recording by ejecting ink droplets of corresponding colors.

  The roll paper 2 is fed by a paper feed unit (not shown), transported by the transport unit 3, and recording is performed by ejecting ink when passing under the recording heads 1K, 1C, 1M, 1Y. The reading unit 4 provided on the downstream side of the recording position of the four recording heads with respect to the roll paper conveyance direction includes a reading unit 41 for optically reading an image. The reading unit 41 inspects the quality of the recorded image from image data obtained by reading the images recorded by the four recording heads. Further, the roll paper 2 is cut by a cutter unit 5 provided on the downstream side of the reading unit 4 in the conveyance direction of the roll paper.

  FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the control unit 20 includes a CPU 21 that controls the entire apparatus, a ROM 22 that stores a control program executed by the CPU 21, and a RAM 23 that serves as a work area necessary for executing the control program and temporarily stores work data. , Including a gate array 24. The gate array 24 inputs and outputs drive control signals to the transport unit 3, image signals and control signals to the recording heads 1K, 1C, 1M, and 1Y, image signals and control signals from the reading unit 4, and the like. The gate array 24 is connected to the image memory 25 and temporarily stores recording data received from the outside in the image memory 25 or temporarily stores image data output from the reading unit 4. Further, main body information is stored in the EEPROM 26.

  Further, the CPU 21 transmits control signals to the transport unit 3 and the cutter unit 5 through the gate array 24 to control these operations, and further performs the recording operations of the four recording heads 1K, 1C, 1M, and 1Y. Control.

  Next, an embodiment of a recorded image inspection process executed by the recording apparatus having the above configuration will be described.

  FIG. 3 is a flowchart for explaining the inspection execution control process for the quality of the recorded image according to the first embodiment. The following processing makes it possible to determine whether or not to inspect an image before recording starts.

  First, in step S1, roll paper is fed, and in step S2, the roll paper is conveyed to a recording start position.

  In step S3, the print buffer is divided into a plurality of areas, and the dot count number of each divided area is determined. This print buffer is defined and provided in the image memory 25.

  FIG. 4 is a diagram schematically showing how the inside of the print buffer is divided.

  As can be seen from FIG. 4, the print buffer has a width that can store recording data corresponding to the width of the recording paper (here, roll paper) and can record an arbitrary number of dots in the transport direction of the roll paper. Has the necessary capacity. In FIG. 4, “the height of an arbitrary number of nozzles” corresponds to the amount of recording data corresponding to recording in the roll paper conveyance direction. Here, for example, the amount of recording data necessary to record 512 dots is used.

  As is apparent from the configuration shown in FIGS. 1 and 2, the recording apparatus can perform color recording using four recording heads. Accordingly, the print data also includes black (K) component, cyan (C) component, magenta (M) component, and yellow (Y) component data corresponding to these four print heads. However, in order to simplify the description, only one color component data is referred to and treated as recording data.

  In the example shown in FIG. 4, the print buffer is divided into a left region_x, a central region_x, and a right region_x in the width direction of the roll paper, and determines the dot count number to be counted in each region. The dot count number is, for example, 512 × left region_x, 512 × center region_x, 512 × right region_x. The dot count number of the print buffer is calculated when the recording data is developed in the print buffer.

  In step S4, an area on the roll paper surface during recording is determined.

  FIG. 5 is a diagram showing an example of how to divide the area on the roll paper surface.

  In FIG. 5, the up and down direction (conveying direction) of the roll paper is divided into a front end region_y, a central region (upper) _y, a central region (lower) _y, and a rear end region_y in order from the top. As shown in FIG. 4, the left and right directions of the roll paper are left region_x, center region_x, and right region_x in order from the left.

  FIG. 6 is a diagram showing the configuration of the image inspection execution determination threshold and the image inspection execution determination flag stored in the EEPROM 26.

  As shown in FIG. 6, the EEPROM 26 is divided into two areas 26A and 26B, and a threshold value (CTH) for execution of image inspection and a flag (CLFG) for execution determination of image inspection are stored in each area. . The threshold value and flag are provided for each roll paper area.

  The transport direction is divided into an end area_y, a central area (upper) _y, a central area (lower) _y, and a rear end area_y, and in the roll paper width direction, the left area_x, the central area_x, and the right area Since it is divided into three parts, _x, the print buffer is divided into 12 areas. Then, a total of 12 threshold values and 12 flags corresponding to each divided area are provided as shown in FIG.

In FIG. 6, these threshold values are expressed as follows. That is,
T_y-L_xCTH (tip region_y_left region_x inspection threshold),
T_y-C_xCTH (tip region_y_center region_x inspection threshold),
T_y-R_xCTH (tip region_y_right region_x inspection threshold),
CU_y-L_xCTH (center region (upper) _y_left region_inspection threshold for x),
CU_y-C_xCTH (center area (upper) _y_center area_x inspection threshold),
CU_y-R_xCTH (center region (upper) _y_right region_inspection threshold for x),
CB_y-L_xCTH (center region (lower) _y_left region_inspection threshold for x),
CB_y-C_xCTH (center region (lower) _y_center region_inspection threshold for x),
CB_y-R_xCTH (center region (bottom) _y_right region_x inspection threshold),
B_y-L_xCTH (rear end region_y_left region_inspection threshold for x),
B_y-C_xCTH (rear end region_y_center region_x inspection threshold),
B_y-R_xCTH (rear end region_y_right region_x inspection threshold),
It is.

  On the other hand, the flag is described as follows.

T_y-L_xCFLG (tip region_y_left region_x inspection execution flag),
T_y-C_xCFLG (tip region_y_center region_x inspection execution flag),
T_y-R_xCFLG (tip region_y_right region_x inspection execution flag),
CU_y-L_xCFLG (center region (upper) _y_left region_x inspection execution flag),
CU_y-C_xCFLG (center region (upper) _y_center region_x inspection execution flag),
CU_y-R_xCFLG (center region (upper) _y_right region_x inspection execution flag),
CB_y-L_xCFLG (center region (lower) _y_left region_x inspection execution flag),
CB_y-C_xCFLG (center region (lower) _y_center region_x inspection execution flag),
CB_y-R_xCFLG (center region (bottom) _y_right region_x inspection execution flag),
B_y-L_xCFLG (rear end region_y_left region_x inspection execution flag),
B_y-C_xCFLG (rear end region_y_center region_x inspection execution flag),
B_y-R_xCFLG (rear end region_y_right region_x inspection execution flag),
It is.

  Note that the above threshold value may differ depending on information such as ink color discharged from the recording head, roll paper, cut paper, and humidity.

  The threshold value is set for each ink color because it is more likely that cockling will occur in the color to be recorded later than the color to be recorded on the paper first, so the threshold value needs to be reduced. Also, in the case of cut paper, the possibility of curling at the leading edge and the trailing edge is higher than that of roll paper, so it is necessary to make it smaller than the threshold value of roll paper. In addition, when the recording apparatus is provided with a humidity sensor, curling is likely to occur in the paper if the humidity is high, and therefore the threshold value needs to be reduced when the measured humidity is high.

  As can be seen from FIG. 6, in this embodiment, the threshold value can be set differently for each region. Specifically, in the front end area_y and the rear end area_y of the paper, the threshold is made smaller than the central area (upper) _y of the paper and the central area (lower) _y of the paper to facilitate the inspection.

  Returning to FIG. 3, the description continues. In step S5, the dot count number in each divided area of the print buffer is compared with the inspection threshold value in the corresponding area shown in FIG. 6 at the time of recording. Then, it is checked whether the dot count number of each area of the print buffer exceeds the inspection threshold value of the paper area. In this check, the amount of recording data that causes ink to be generated from the recording head is counted for the recording data stored in each region. As a result, it is determined for each region whether the dot count is large, that is, whether ink is ejected and the recording density is high.

  As a result of this check, if it is determined that the dot count number exceeds the threshold value (that is, the area has a high density), the process proceeds to step S6, and the current paper area is determined to deal with it. The execution determination flag for the image inspection in the area to be set is set (flag value is “1”). On the other hand, if it is determined that the dot count value does not exceed the threshold value, the process proceeds to step S7, where the current paper area is determined, and the image inspection execution determination flag in the corresponding area is cleared. (Flag value is “0”).

  Thereafter, in step S8, it is confirmed that the roll paper passes the reading unit 41. At this point, the recording on the roll paper has been completed, and the reading of the recorded image itself is completed by passing through the reading unit 41. In step S9, it is read from the EEPROM 26 and it is checked whether or not the image inspection execution flag set for each roll paper area is set. If the flag is set, the process proceeds to step S10, and inspection of image data obtained by reading the recorded image with the reading unit 4 is executed for the area where the flag is set. This inspection is performed based on the image data corresponding to the area specified by the flag among the image data obtained by reading the recorded image. On the other hand, if no flag is set in any of the areas, the process ends as it is.

  Therefore, according to the above-described embodiment, the recording operation is not stopped, and a portion having a high possibility of causing an image defect, in particular, only a high density region is determined and only the region is inspected. Can be inspected.

  In the first embodiment, the example in which the image inspection is executed for the region for which the inspection execution flag is set has been described. Here, an example in which the entire region is detected will be described.

  FIG. 7 is a flowchart for explaining the inspection execution control process for the quality of a recorded image according to the second embodiment. In FIG. 7, the same processing steps as those already described with reference to FIG. 3 are denoted by the same step reference numerals, and the description thereof is omitted. Also in this embodiment, it is determined whether or not to inspect an image before starting recording.

  After the processing of steps S1 to S8, in step S9, it is read out from the EEPROM 26 and it is checked whether or not the image inspection execution flag set for each roll paper area is set. Here, if the flag is set, the process proceeds to step S11, and inspection of image data obtained by reading by the reading unit 4 is executed with respect to the area where the flag is set. Next, in step S12, the image data is also inspected for the portion for which the inspection execution flag is not set.

  On the other hand, if it is confirmed in step S9 that no flag is set in any area, the process ends.

  Therefore, according to the embodiment described above, the portion having a high possibility of a defect is checked, and then the portion having a low possibility is checked and the entire area of the image is inspected. When executed, it is possible to detect a defect in image inspection earlier.

1K, 1C, 1M, 1Y recording head, 3 transport unit, 4 reading unit,
20 control unit, 21 CPU, 25 image memory

Claims (12)

A recording apparatus that performs recording by ejecting ink from a recording head having a recording width longer than the width of the recording medium to the recording medium,
Buffer means for storing recording data used for recording by the recording head;
Conveying means for conveying the recording medium;
The area of the buffer means for storing the recording data is divided into a plurality of areas corresponding to the width direction of the recording medium and the conveyance direction of the recording medium, and the recording is stored in each of the divided areas. Counting means for counting dots that cause ink ejection from the recording head for each of the plurality of regions based on the data;
A reading unit provided on a downstream side of a recording position by the recording head with respect to a conveying direction of the recording medium by the conveying unit, and reading an image recorded by the recording head;
Based on the value counted by the counting means, an area having a high density in the image recorded by the recording head is specified, and the specified area is based on image data obtained from reading by the reading means. And an inspection means for inspecting an image recorded by the recording head. For each of the plurality of regions, storage means for storing a threshold value for comparison with the value counted by the counting means, and a flag for setting the result of the comparison;
For each of the plurality of regions, a comparison unit that compares a value counted by the counting unit with a corresponding threshold value;
For each of the plurality of regions, as a result of comparison by the comparison means, if the value counted by the counting means exceeds the corresponding threshold value, a corresponding flag is set, and the value counted by the counting means is 2. The recording apparatus according to claim 1, further comprising setting means for clearing a corresponding flag if the corresponding threshold is not exceeded.   The recording apparatus according to claim 2, wherein the inspection unit includes a specifying unit that specifies which of the plurality of regions is a high-density region from a flag stored in the storage unit.   The recording apparatus according to claim 3, wherein the inspection unit performs the inspection on the area where the flag is not set after performing the inspection on the area where the flag is set.   5. The threshold value is set to be different in a region corresponding to the front end and the rear end and a region corresponding to the central region in the conveyance direction of the recording medium among the plurality of regions. The recording apparatus according to any one of the above. A plurality of the recording heads are arranged in the conveying direction of the recording medium,
The recording apparatus according to claim 2, wherein color recording is performed by ejecting different color inks from the plurality of recording heads.   The recording apparatus according to claim 6, wherein the threshold value stored in the storage unit is further set to a different value according to the color of ink ejected from the plurality of recording heads.   The recording apparatus according to claim 2, further comprising a humidity sensor that measures humidity.   The recording apparatus according to claim 8, wherein the threshold value stored in the storage unit is further set to a different value according to the humidity measured by the humidity sensor.   The recording apparatus according to claim 2, wherein the recording medium includes roll paper and cut paper.   11. The recording according to claim 10, wherein the threshold value stored in the storage means is further set to a different value depending on whether the recording medium used is roll paper or cut paper. apparatus. An inspection method in a recording apparatus for performing recording by discharging ink from a recording head having a recording width longer than the width of the recording medium to a recording medium to be conveyed,
A buffer area for storing recording data used for recording by the recording head is divided into a plurality of areas corresponding to the width direction of the recording medium and the conveyance direction of the recording medium, and each of the divided plurality of areas is divided. A counting step of counting dots that cause ink ejection from the recording head for each of the plurality of regions based on stored recording data;
Based on the value counted in the counting step, a region having a high density in the image recorded by the recording head is specified, and the recording head performs recording with respect to the specified region with respect to the conveyance direction of the recording medium. And an inspection step for inspecting an image recorded by the recording head based on image data obtained from reading of a reading unit that is provided downstream of the position and reads an image recorded by the recording head. Inspection method.

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