JP2012111153A - Printing apparatus and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new and improved printing apparatus that can adjust density using a simple and basic medium, and to provide a printing method.SOLUTION: The printing apparatus includes: first printing images; second printing images having usage different from those of the first printing images, and including relevant images and density correcting patterns indicative of information relevant to printing behaviors of the first printing images; a printing part that performs printing on the medium; a reading part that reads density correcting patterns of the second printing images that are printed on the medium by the printing part; and a control part that calculates density correcting values of the first printing images based on the density correcting patterns read by the reading part.

Description

  The present invention relates to a printing apparatus and a printing method.

  Examples of the printing apparatus include a printer that prints an image on a medium such as roll paper. As the usage form of this printer, the importance of print vending machines has increased with the recent spread of digital cameras.

  Incidentally, it is known that the image quality of a printed image varies in the print described above. As a factor of image quality fluctuation, for example, fluctuation of environmental temperature where the printer is installed can be cited. In order to suppress such fluctuations in image quality, there is a method of periodically printing a density correction pattern and performing density correction based on the printed density correction pattern (see Patent Documents 1 to 4).

Japanese Patent Laid-Open No. 2003-94782 JP-A-2005-204105 JP 2003-131467 A JP 2001-239731 A

  Conventionally, since the user selects a pattern closest to the reference density from among the printed density correction patterns, the user is forced to perform inconvenient work. Further, since density correction is performed by printing only the density correction pattern on the medium, there is a problem that the medium is used every time density correction is performed and the amount of consumption of the medium increases.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved printing apparatus capable of adjusting the density with a simple and minimal medium, and printing. It is to provide a method.

  In order to solve the above problem, according to an aspect of the present invention, the first print image and the first print image are second print images having different uses, and the first print image is printed. A printing unit that prints a related image indicating related information and a second print image including both density correction patterns on a medium, and the density correction pattern of the second print image printed on the medium by the printing unit. A density correction value of the first print image is calculated based on the reading unit to be read and the density correction pattern read by the reading unit, and the first print image is printed on the printing unit based on the calculated density correction value. A printing apparatus including a control unit is provided.

  The medium is transported in a predetermined transport direction, the density correction pattern includes a plurality of patterns having different densities, and the printing unit includes an upstream side in the transport direction of the related image on the medium and the transport direction. The second print image may be printed on the medium such that the plurality of patterns are positioned on the downstream side.

  In addition, the medium is transported in a predetermined transport direction, the density correction pattern includes a plurality of patterns having different densities, and the related image includes a plurality of images that are spaced apart along the transport direction, The printing unit may print the second print image on the medium such that boundaries of the plurality of patterns in the transport direction coincide with boundaries of the plurality of images.

  The printing unit may include a sublimation type thermal head, and the thermal head may print the density correction pattern every time the related image is printed.

  Further, the related image may be a slip image indicating slip information when the first print image is printed.

  The related image may be a thumbnail image corresponding to each of the plurality of first print images.

  In order to solve the above-described problem, according to another aspect of the present invention, the second print image has a different use from the first print image, and information related to the printing operation of the first print image is obtained. Printing a second print image including both the related image and the density correction pattern to be printed on a medium; reading the density correction pattern of the second print image printed on the medium; and reading the density correction pattern And a step of calculating a density correction value of the first print image based on the first print image and printing the first print image on the medium based on the calculated density correction value.

  As described above, according to the present invention, it is possible to provide a new and improved printing apparatus and printing method capable of adjusting the density with a simple and minimum necessary medium.

1 is a diagram illustrating an example of an external configuration of a print vending machine 1. FIG. 1 is a block diagram showing an example of the overall configuration of a print vending machine 1. FIG. FIG. 2 is a diagram illustrating an example of an internal configuration of a print vending machine 1. 6 is a flowchart for explaining a conventional operation example of the print vending machine 1; It is a figure for demonstrating the printed slip. It is a flowchart for demonstrating the operation example of the printing vending machine 1 at the time of printing a slip | sheet with a density | concentration measurement pattern. It is a figure for demonstrating a slip with a density | concentration measurement pattern. It is a figure which shows the slip with a density | concentration measurement pattern in which sticking generate | occur | produced. The 1st modification of a slip with a density | concentration measurement pattern is shown. The 2nd modification of a slip with a density | concentration measurement pattern is shown. It is a figure for demonstrating the 3rd modification of a slip with a density | concentration measurement pattern. It is a figure for demonstrating the RGB value of each pattern of a density | concentration measurement pattern. It is a figure for demonstrating the specific density correction method. It is a figure for demonstrating the specific density correction method. A density correction table is shown. It is a figure which shows a mode that the density | concentration measurement pattern was printed with several thumbnail images.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be made in the following order.
1. 1. First embodiment 1-1. Configuration example of print vending machine 1-1-1. External configuration of print vending machine 1-1-2. Internal configuration of print vending machine 1-2. Conventional operation example of print vending machine 1-3. Regarding density correction 1-4. Example of operation of printing vending machine when printing slip with density measurement pattern 1-5. Another embodiment of slip with density measurement pattern 1-6. Density correction processing 1-7. 1. Effectiveness of the print vending machine according to the first embodiment. Second embodiment 3. Other embodiments

<1. First Embodiment>
(1-1. Configuration Example of Print Vending Machine)
A printing vending machine 1 will be described as an example of a printing apparatus. The print vending machine 1 is a self-service printer that can print an image (for example, a photographic image) with high quality. The print vending machine 1 is installed in stores, streets, specific event venues, and the like, and is used by unspecified users.

  Below, the structural example of the printing vending machine 1 is demonstrated, referring FIGS. 1-3. FIG. 1 is a diagram illustrating an external configuration example of a print vending machine 1. FIG. 2 is a block diagram illustrating an example of the overall configuration of the print vending machine 1. FIG. 3 is a diagram illustrating an internal configuration example of the print vending machine 1.

(1-1-1. External configuration of print vending machine)
First, the external configuration of the print vending machine 1 will be described with reference to FIG. The print vending machine 1 includes a housing 3, a touch panel screen 5, an insertion slot (slot) 7, and an outlet 9.

  The housing 3 has a box shape. Inside the housing 3, a printing unit that prints various images on paper, a control device, and the like are provided.

  The touch panel screen 5 is provided in the upper front part of the housing 3. The touch panel screen 5 has a structure in which a touch panel is arranged on the display screen. For example, the user performs various operations on the touch panel while viewing the display on the display screen of the touch panel screen 5.

  The insertion port 7 is provided at the front center of the housing 3. A portable external storage medium (in the following, a memory card will be described as an example) is inserted into the insertion slot 7. The memory card stores image data to be printed. The print vending machine 1 can read image data stored in a memory card inserted into the insertion slot 7 and print an image (photo image) on paper.

  The outlet 9 is provided in the lower front part of the housing 3. A paper on which an image corresponding to the image data of the memory card is printed is discharged to the outlet 9. The print vending machine 1 according to the present embodiment can print slip images on paper and discharge them.

  Although not shown in FIG. 1, the print vending machine 1 is connected so as to be communicable with other terminal devices. The print vending machine 1 can print an image based on a print command from another terminal device.

(1-1-2. Internal configuration of print vending machine)
The print vending machine 1 has a printer function as described above, and is a thermal transfer printer in this embodiment. Specifically, the printer vending machine 1 uses a thermal head to transfer sublimation dye ink applied to an ink ribbon onto roll paper, which is an example of a long medium, thereby printing an image on the roll paper. Type printer. Of course, a melt-type printer, a thermal printer, or the like may be used.

  Below, the internal structure of the printing vending machine 1 which is a sublimation type printer is demonstrated, referring FIG.2 and FIG.3.

  As shown in FIG. 2, the print vending machine 1 includes a roll paper transport unit 20, an ink ribbon transport unit 30, a head unit 40 that is an example of a printing unit, a cutter unit 50, a display unit 60, and a control unit. It has the controller 70 which is an example.

  The roll paper transport unit 20 transports the roll paper S in the transport direction. As shown in FIG. 3, the roll paper transport unit 20 includes a paper feed roller 22, a capstan roller 23, a pinch roller 24, and a platen roller 25.

  The paper feed roller 22 feeds the roll paper S held by the holder 21 toward the thermal head 41 located on the downstream side in the transport direction. The capstan roller 23 sandwiches and conveys the roll paper S together with the pinch roller 24 that is a driven roller. The capstan roller 23 is rotatable in the forward direction (counterclockwise in FIG. 3) and the reverse direction (clockwise in FIG. 3), and feeds and pulls back the roll paper S in the transport direction. For example, the capstan roller 23 feeds the roll paper S when rotating in the forward direction, and pulls back the roll paper S when rotating in the reverse direction. The platen roller 25 is provided at a position facing the thermal head 41 and supports the roll paper S being conveyed.

  The ink ribbon transport unit 30 transports the ink ribbon R. As shown in FIG. 3, the ink ribbon transport unit 30 includes a supply reel 31 and a take-up reel 32. The ink ribbon R unwound from the supply reel 31 is conveyed along with the rotation of the take-up reel 32, passes between the thermal head 41 and the platen roller 25, and is taken up by the take-up reel 32.

  Here, the ink ribbon R will be described. The print vending machine 1 prints a color image on the roll paper S. For this reason, three colors of sublimation dyes of Y (yellow), M (magenta), and C (cyan) are applied to the ink ribbon R in different colors. In addition to the above three colors, the ink ribbon R may be coated with a K (black) color or a transparent laminate ink. When the ink ribbon R on the supply reel 31 is no longer used, it is replaced with a new one.

  The head unit 40 transfers the ink applied to the ink ribbon R onto the roll paper S. The head unit 40 includes a thermal head 41 in which a plurality of heating elements (not shown) are arranged in a line. The plurality of heating elements are selectively energized according to the gradation level of the printed image, and generate thermal energy used for ink transfer.

  The thermal head 41 moves between a standby position and a transfer position where the ink is transferred to the roll paper S. The standby position is a position where the thermal head 41 is separated from the platen roller 25, and the transfer position is a position where the thermal head 41 holds the roll paper S and the ink ribbon R together with the platen roller 25. The thermal head 41 transfers the ink applied to the ink ribbon R onto the roll paper S when positioned at the transfer position. In the present embodiment, the ink ribbon R is fed in the same direction as the roll paper S, and when the roll paper S is pulled back by the capstan roller 23, the ink applied to the ink ribbon R is rolled. Transferred to the paper S.

  The cutter unit 50 is provided on the downstream side of the thermal head 21 in the transport direction. The cutter unit 50 has a blade for cutting roll paper, and the roll paper S on which an image is printed is cut into cut paper of a predetermined size by the blade. The cut cut paper is discharged to the outlet 9 (FIG. 1).

  The display unit 60 displays information on the display screen of the touch panel screen 5 (FIG. 1) described above. The display unit 60 also has a function of accepting input by the user operating the touch panel.

  The memory card attaching / detaching unit 65 has the insertion slot 7 (FIG. 1) described above, and detects the attachment / detachment of the memory card with respect to the insertion slot 7. For example, when a memory card is inserted into the insertion slot 7, information is displayed on the display screen of the patch panel screen 5.

  The controller 70 controls each unit. Specifically, the controller 70 controls each unit of the print vending machine 1 through the unit control circuit 74 by the CPU 71 according to a program stored in the memory 72. The controller 70 can communicate with another terminal device (not shown) via the interface 73. When the controller 70 receives a print command from another terminal device, the controller 70 prints an image stored in the memory card inserted into the insertion slot 7 on the roll paper S.

  The detector 80 detects the situation in the print vending machine 1. As shown in FIG. 3, the detector 80 includes a reading sensor 81, which is an example of a reading unit that reads an image printed on the roll paper S, on the upstream side in the transport direction of the thermal head 41. The detector 80 includes a position detection sensor that detects the position of the roll paper S and the ink ribbon R on the transport path. The detector 80 outputs a signal corresponding to the detection result of the sensor toward the controller 70. The controller 70 receives the signal and controls each unit.

(1-2. Conventional operation example of print vending machine)
Next, a conventional operation example of the print vending machine 1 when printing image data stored in the memory card will be described with reference to FIG. FIG. 4 is a flowchart for explaining a conventional operation example of the print vending machine 1. The left side of FIG. 4 shows the operation contents of the user, and the right side shows the operation contents of the print vending machine 1. The operation of the print vending machine 1 is realized by the controller 70 executing a program stored in the memory 72.

  This flowchart is started when the user inserts the memory card into the insertion slot 7 of the print vending machine 1 (step S2). When the memory card is inserted into the insertion slot 7, the controller 70 of the print vending machine 1 displays a list of image data stored in the memory card on the display screen of the touch panel screen 5.

  Next, the user selects image data to be printed from the image data list displayed on the display screen using the touch panel (step S4). At that time, the user can also select printing conditions (for example, size and number of sheets). In order to print, the user confirms the print order (step S6).

  The controller 70 of the print vending machine 1 causes the head unit 40 to print a slip based on the confirmed print order on the roll paper S before printing the image data selected by the user on the roll paper S on the head unit 40 (step S40). S22). Then, the controller 70 cuts and discharges the roll paper S on which the slip is printed (step S24). The reason for discharging the slip first is that after the slip is shown to the store clerk and the payment is completed, the store clerk operates the terminal device to send a print command to the print vending machine 1 so that the print vending machine 1 displays the image. This is because it is a printing system.

  Here, the printed slip will be described with reference to FIG. FIG. 5 is a diagram for explaining a printed slip. The left diagram in FIG. 5 shows the background of the slip, and the right diagram shows the printed slip. The slip includes background and order information. The background can be created for each store. The order information indicates the printing conditions selected by the user. The order information is, for example, character information such as date, time, order number, size, menu, number of sheets, unit price, fee, total amount, etc., and graphic information such as a barcode. Note that the order information and the graphic information correspond to a plurality of images that are located apart along the transport direction.

  Returning to the flowchart of FIG. The user passes the discharged slip to the store clerk and pays it (step S8). The store clerk operates the terminal device to transmit a print command based on the order information to the print vending machine 1. The controller 70 that has received the print command causes the head unit 40 to print the image data to be printed out of the image data stored in the memory card on the roll paper S in accordance with the print command (step S26).

  Next, the controller 70 cuts the roll paper S on which the image data to be printed is printed, and discharges the roll paper S to the roll paper transport unit 20 through the take-out port 9. Thereby, the user receives the discharged photo (step S10). When the print vending machine 1 finishes printing all the image data to be printed, the user removes the memory card inserted into the insertion slot 7 (step S12). Thereby, a series of operation | movement is complete | finished.

(1-3. Density correction)
By the way, in the above-described print vending machine 1, it is known that the image quality of a printed image varies. As a factor of image quality fluctuation, for example, fluctuation of environmental temperature where the printing vending machine 1 is installed can be cited. The print vending machine 1 has a case where it is set in a place where air conditioning is ineffective such as an entrance of a store due to characteristics used by an unspecified number of users, and the environmental temperature is likely to fluctuate.

  In addition to image quality variation due to environmental temperature, the image quality varies due to variations in color development characteristics of the ink ribbon R and variations in the printing vending machine 1 (variations in the shape and resistance value of the thermal head 41). In particular, the ink ribbon R is a consumable item, and the image quality is likely to vary with the replacement of the ink ribbon R having a different production lot.

  In order to suppress such fluctuations in image quality, there is a method in which a density correction pattern is printed periodically and density correction is performed based on the printed density correction pattern. The density correction pattern is printed, for example, when the ink ribbon R is replaced, when a specific number of sheets are printed, when a specific time elapses, and when the printing vending machine 1 is turned on. However, the print timing of the density correction pattern and the use timing of the print vending machine 1 by the user may differ. In such a case, even if the density correction is performed with the density correction pattern, the environmental temperature is changed, so that the image quality is changed.

  In addition, the roll paper S and the ink ribbon R are used to print the density correction pattern. However, when the number of times the density correction pattern is printed increases, the consumption of the roll paper S and the ink ribbon R increases. is there.

  In order to solve the above-described problem, in the print vending machine 1 of the present embodiment, a density measurement pattern (density correction) for calculating a density correction value in addition to order information is added to a slip printed immediately before printing an image. Pattern) is printed at the same time. That is, the print vending machine 1 prints a slip with a density measurement pattern (details will be described later).

  Thus, immediately after the density correction pattern is printed, the image data of the memory card is printed by applying the density correction value calculated based on the printed density correction pattern, so that fluctuations in image quality after density correction can be suppressed. . Also, since the density measurement pattern is printed on the slip, unlike the case where only the density correction pattern is printed on the head unit 40, the problem of wastefully consuming the roll paper S and the ink ribbon R can be solved.

(1-4. Example of operation of print vending machine when printing slip with density measurement pattern)
Next, an example of the operation of the printing vending machine 1 when printing a slip with a density measurement pattern will be described with reference to FIG. FIG. 6 is a flowchart for explaining an operation example of the print vending machine 1 when printing a slip with a density measurement pattern. The user operation content (steps S2 to S12) in the flowchart of FIG. 6 is the same as the user operation content (steps S2 to S12) shown in the flowchart of FIG. Explained. The operation of the print vending machine 1 is realized by the controller 70 executing a program stored in the memory 72.

  The flowchart of FIG. 6 is also started when the user inserts the memory card into the insertion slot 7 of the print vending machine 1 as in FIG. 4 (step S2). When the memory card is inserted into the insertion slot 7, the controller 70 of the print vending machine 1 displays a list of image data stored in the memory card on the display screen of the touch panel screen 5.

  Next, the user selects image data to be printed from the image data list displayed on the display screen using the touch panel (step S4), and confirms the print order (step S6). Then, before printing the selected image data on the roll paper S on the head unit 40, the controller 70 causes the head unit 40 to print a slip with a density measurement pattern on the roll paper S on the head unit 40 (step S42).

  Here, the slip with the density measurement pattern will be described with reference to FIG. FIG. 7 is a diagram for explaining a slip with a density measurement pattern. The left diagram of FIG. 7 shows a slip image, the center diagram shows a density measurement pattern, and the right diagram shows a slip with a density measurement pattern. In the slip with density measurement pattern, the slip image corresponding to the related image is located in the center, and the density measurement pattern corresponding to the density correction pattern is located around the slip image. The right side of FIG. 7 (printed image) corresponds to the second printed image (the image printed with the image data of the memory card corresponds to the first printed image).

  The slip image is the same image as the slip shown in FIG. The density measurement pattern is located around the slip image (up / down / left / right). This density measurement pattern is a pattern in which three colors of R, G, and B are mixed, and gray is changed from black to white in 16 steps (R, G, B) = (0, 0, 0), (17, 17, 17),... (255, 255, 255) and the changed solid areas are arranged. That is, in this embodiment, the density measurement pattern includes 16 patterns having different densities.

  Returning to the flowchart of FIG. The controller 70 causes the capstan roller 23 to transport the roll paper S on which the slip with density measurement pattern is printed, to the upstream side in the transport direction. Specifically, the capstan roller 23 transports the roll paper S to the upstream side in the transport direction so that the density measurement pattern portion faces the reading sensor 81 (FIG. 3) provided on the transport path.

  Next, the controller 70 reads the density measurement pattern by the reading sensor 81 (step S44). Thereby, the controller 70 can measure the density of the density measurement pattern. Next, the controller 70 stores the density measurement value in the memory 72 (step S46). In addition, the controller 70 performs density correction processing described later, and also stores the density correction value in the memory 72.

  When the density measurement pattern is read by the reading sensor 81, the controller 70 conveys the roll paper S to the downstream side in the conveyance direction. Then, the controller 70 cuts the roll paper S by the cut unit 50 and discharges the slip with the density measurement pattern (step S48).

  Next, the user hands over the discharged slip with density measurement pattern to the store clerk and pays it (step S8). The store clerk operates the terminal device to transmit a print command based on the order information to the print vending machine 1. The controller 70 that has received the print command causes the image data to be printed out of the image data stored in the memory card to be subjected to density correction and printed on the roll paper S in accordance with the print command (step S50). That is, the controller 70 performs density correction based on the density correction value stored in the memory 72 and prints an image on the roll paper S.

  Next, the controller 70 cuts and rolls out the roll paper S on which the image data has been printed with the density corrected, and discharges the roll paper S to the outlet 9. Thereby, the user receives the discharged photo (step S10). When the print vending machine 1 finishes printing all the image data to be printed, the user removes the memory card inserted into the insertion slot 7 (step S12). Thereby, a series of operation | movement is complete | finished.

  According to the above-described process, by printing the slip with the density measurement pattern, density correction can be performed immediately before printing the image data of the memory card, so that fluctuations in image quality can be suppressed. Further, since the density measurement pattern is printed together with the slip, it is not necessary to print only the density measurement pattern, and it is possible to prevent wasteful consumption of the roll paper S and the ink ribbon R.

  Further, each time the vending machine 1 prints a slip on the roll paper S, it also prints a density measurement pattern and reads the density measurement pattern by the reading sensor 81. Accordingly, density correction is performed each time a slip is printed, and an image reflecting the density correction is easily printed on the roll paper S. Note that the density measurement pattern does not have to be printed every time the slip is printed. For example, when the slip is printed after a predetermined time has passed since the previous density measurement pattern was printed, the density measurement pattern is not printed. It may be printed.

(1-5. Other embodiment of slip with density measurement pattern)
By the way, it is known that a phenomenon in which a white line called sticking is printed occurs during printing in a sublimation type printer. This white line occurs when there is a portion in the printed image where the gradation changes extremely in the transport direction of the roll paper S (the boundary between the high density portion and the low density portion in the transport direction). More specifically, sticking occurs when there is a large gradation difference in the transport direction and a portion having the gradation difference is long in the main scanning direction (direction orthogonal to the transport direction). In particular, when the printing speed is high, the friction between the thermal head 41 and the ink ribbon R greatly changes during printing of the corresponding part. Note that the frequency of sticking varies depending on the surrounding environmental conditions.

  Sticking can also occur when printing a slip with a density measurement pattern. FIG. 8 is a diagram showing a slip with density measurement pattern in which sticking has occurred. As shown in FIG. 8, in the density measurement pattern, a white line is generated along the direction orthogonal to the transport direction on the downstream side of the two barcodes in the transport direction. The white line is located at the boundary between the barcode of the slip portion and the white background, as indicated by the arrow in FIG. In addition, white lines are also formed on the upstream side and the downstream side in the transport direction of the store logo.

  When a white line is generated in the density measurement pattern portion, the accuracy of density measurement is lowered. For this reason, it is necessary to prevent sticking from occurring in the density measurement pattern portion from the viewpoint of preventing a decrease in density measurement of the pattern. When only the density measurement pattern is printed without including the slip portion, sticking hardly occurs.

  In order to prevent a white line from occurring in the density measurement pattern portion, the print vending machine 1 prints a slip with a density measurement pattern shown in FIG. 9, for example. FIG. 9 shows a first modification of the slip with the density measurement pattern. The difference between the slip with density measurement pattern in FIG. 9 and the slip with density measurement pattern in FIG. 7 described above is that the printing position of the density measurement pattern is different. That is, in FIG. 9, the density measurement pattern is printed only on the upper side and the lower side of the slip portion (in other words, on the upstream side in the transport direction and the downstream side in the transport direction), and not on the left side and the right side. As a result, even if there is a portion where the gradation greatly changes in the slip portion (portion indicated by an arrow in FIG. 9), no white line is generated in the density measurement pattern.

  In FIG. 9, the density measurement pattern is printed on the upper and lower sides of the slip portion, but the present invention is not limited to this. For example, the density measurement pattern may be printed only on either the upper side or the lower side of the slip portion.

  FIG. 10 shows a second modification of the slip with the density measurement pattern. The slip with density measurement pattern in FIG. 10 includes a head correction pattern P2 in addition to the density measurement pattern P1 in FIG. The head correction pattern is a pattern for correcting the unevenness of the thermal head 41 and the unevenness of the resistance value in the main scanning direction (direction orthogonal to the transport direction). The tone value of the head correction pattern is constant. When printing the slip with density measurement pattern in FIG. 10, two types of correction can be performed by printing two types of test patterns on the slip and causing the reading sensor 81 to read them.

  As described above, it has been described that the pattern is printed only on the upper and lower sides of the slip portion so that no white line is generated in the density measurement pattern. However, in the following, the pattern is printed on the left and right sides of the slip portion. A technique for avoiding the effects of sticking will be described.

  In this method, as shown in FIG. 11, each pattern is printed so that a white line is positioned at the boundary between a plurality of patterns constituting the density measurement pattern. For example, if the data in the slip portion is analyzed in advance and sticking is likely to occur, the position and width of the pattern in the conveyance direction are changed (see the arrow in FIG. 11), and the pattern boundary becomes the sticking occurrence portion. Print the density measurement pattern so that it is positioned. According to such a method, even if sticking occurs at the boundary of the pattern, it is difficult to adversely affect the density measurement of each pattern (this is because the density measurement is performed by extracting the central portion of the pattern). Measurement can be performed with high accuracy. In addition, FIG. 11 is a figure for demonstrating the 3rd modification of a slip with a density | concentration measurement pattern. The right diagram in FIG. 11 shows a state in which sticking has occurred in the density measurement pattern, and the left diagram shows how the white line is located at the boundary of the pattern.

  As described above, according to the density measurement patterns of FIGS. 9 to 11, it is possible to prevent a decrease in density measurement accuracy due to sticking that occurs when printing a slip including both the slip portion and the density measurement pattern.

(1-6. Density Correction Processing)
A density correction process based on the density measurement pattern read by the reading sensor 81 will be described. The density correction process is executed by the controller 70.

  First, an outline of density correction processing according to the present embodiment will be described. As described above, since the density measurement pattern is a pattern in which three colors (R, G, B) are mixed, the controller 70 determines each pattern (16 levels of density measurement pattern) from the data read by the reading sensor 81. RGB values of (gradation) are acquired. The acquired RGB values are compared with reference data. Here, the reference data is a density value assumed when each pattern is read by the reading sensor 81, and is stored in the memory 72 in advance. Then, the controller 70 compares the acquired RGB values with the reference data, and calculates a correction table of RGB values (density correction values) to be applied at the next and subsequent printing.

  Next, an actual correction table creation method will be described with reference to FIGS. FIG. 12 is a diagram for explaining the RGB values of each pattern of the density measurement pattern. 13 and 14 are diagrams for explaining a specific density correction method. FIG. 15 shows a density correction table.

  As shown in FIG. 12, for each pattern R (N), G (N), and B (N) (N is an integer of 0 to 15) of the density measurement pattern read by the reading sensor 81, N and (N + 1). The 15 steps in between are linearly interpolated. As a result, 256 levels of R256 (n), G256 (n), and B256 (n) (where n is 0 to 255) are created.

For example, when N = 10 in FIG. 12 and the values of the scanned 10th and 11th patterns are R (10) = 169 and R (11) = 184, linear interpolation is performed as follows: Become.
R (10) = R256 (170) = 169,
R256 (171) = 169.98,
...
R256 (186) = 183.12.
R (11) = R256 (187) = 184

  On the other hand, the reference data (measured values of each pattern in the ideal state) stored in the memory 72 are Rbase (N), Gbase (N), and Bbase (N). Then, N is changed from 0 to 15 in the reference data, and R256 (n), G256 (n), and B256 (n) are compared for each color. 256 (n) having the closest value for each reference data is an ideal RGB value when printing.

  For example, as shown in FIG. 13, if the reference Rbase (10) = 172, R256 (173) = 171.65 and R256 (174) = 172.53, so the closest value is R256 (173). Become. Similarly, R255 (n) close to each of Rbase (N) is obtained as shown in FIG.

  After the calculation of FIG. 14, linear interpolation is performed so that a total of 256 gradations is obtained, and the density correction table shown in FIG. 15 is obtained. The subsequent image is printed with reference to the density correction table.

(1-7. Effectiveness of Print Vending Machine According to First Embodiment)
As described above, the print vending machine 1 prints a slip with a density measurement pattern, reads the printed density measurement pattern with the reading sensor 81, and performs density correction processing. Then, after the density correction process, the image data stored in the memory card is printed using the density correction value.

  As a result, the density correction is executed immediately before the image data stored in the memory card is printed, so that the image data is printed with the density corrected appropriately. Further, the consumption of the roll paper S and the ink ribbon R can be suppressed as compared with the case where only the density measurement pattern is printed on the head unit 40. Further, in the case of the thermal head as in this embodiment, even if the slip and the density measurement pattern are printed together, the replacement frequency of the ink ribbon R does not change, so that the slip and the density measurement pattern are printed separately. It is more effective than that.

  Even if the user or the store clerk does not instruct the density correction process, the density correction process is automatically performed every time the slip is printed. For this reason, troublesome work for the user or the like is eliminated, and the user-friendly print vending machine 1 can be provided.

<2. Second Embodiment>
In the first embodiment, the density measurement pattern is printed on a slip as shown in FIG. On the other hand, the second embodiment is characterized in that the density measurement pattern is printed together with the thumbnail image of the image to be printed. The second embodiment is the same as the first embodiment except that the density measurement pattern is printed together with the thumbnail image.

  FIG. 16 is a diagram illustrating a state in which a density measurement pattern is printed together with a plurality of thumbnail images. A thumbnail image is a reduced image of image data stored in a memory card. A plurality of thumbnail images are printed. The density measurement pattern is the same pattern as in the first embodiment. In the second embodiment, the thumbnail image corresponds to the related image.

  The print sales machine 1 prints thumbnail images of the image data to be printed before printing the image data on the memory card. This thumbnail image is used as an index. In the second embodiment, the density measurement pattern is printed together with the thumbnail image, and after adjusting the density, the correction value is applied to print the image data. For this reason, fluctuations in image quality in an image printed after a thumbnail image can be suppressed. Further, as in the first embodiment, since only the density measurement pattern is not printed, wasteful consumption of the roll paper S and the ink ribbon R can be prevented.

  Further, the density measurement patterns are located on the upper side and the lower side of the image group of the thumbnail images, as in FIG. For this reason, also in 2nd Embodiment, the fall of the precision of the density | concentration measurement by sticking can be prevented.

<3. Other Embodiments>
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  In the above embodiment, the thermal transfer type printer has been described as an example, but the present invention is not limited to this. For example, the present invention can be applied to various printers such as an ink jet printer. Further, the present invention can be applied not only to a printer but also to an image forming apparatus such as a copying machine or a facsimile that can form an image on roll paper.

  In the above embodiment, the roll paper to which the ink applied to the ink ribbon is transferred has been described as an example. However, the present invention is not limited to this. For example, it may be a roll paper that is printed without using an ink ribbon.

  In the above embodiment, the slip with the density measurement pattern is printed before printing the image data. However, the present invention is not limited to this. For example, in a print vending machine in which a slip is printed after image data is printed, a slip with a density measurement pattern may be printed after the image data is printed.

  In the above-described embodiment, the print vending machine is an integrated apparatus including both a touch panel screen and a printing unit (head unit or the like). However, the present invention is not limited to this. For example, an apparatus in which a touch panel screen and a printing unit are separated may be used.

  In the above embodiment, the density measurement pattern is printed together with the slip image or the thumbnail image, but may be printed together with an image other than these images. Further, the density measurement pattern may be in a mode (for example, a line) other than the rectangular shape shown in FIG.

DESCRIPTION OF SYMBOLS 1 Print vending machine 3 Case 5 Touch panel screen 7 Insertion slot 9 Takeout 20 Roll paper conveyance unit 21 Holder 22 Paper feed roller 23 Capstan roller 24 Pinch roller 25 Platen roller 30 Ink ribbon conveyance unit 31 Supply reel 32 Take-up reel 40 Head Unit 41 Thermal head 50 Cutter unit 60 Display unit 65 Memory card attaching / detaching unit 70 Controller 71 CPU
72 Memory 73 Interface 74 Unit control circuit 80 Detector 81 Reading sensor R Ink ribbon S Roll paper

Claims (7)

The first print image is a second print image having a different use from the first print image, and includes a related image indicating information related to a print operation of the first print image and a density correction pattern. A printing section for printing an image on a medium;
A reading unit that reads the density correction pattern of the second print image printed on the medium by the printing unit;
A control unit that calculates a density correction value of the first print image based on the density correction pattern read by the reading unit, and causes the printing unit to print the first print image based on the calculated density correction value;
A printing apparatus comprising: The medium is transported in a predetermined transport direction,
The density correction pattern includes a plurality of patterns having different densities,
2. The printing unit according to claim 1, wherein the printing unit prints the second print image on the medium such that the plurality of patterns are located on the upstream side in the transport direction and the downstream side in the transport direction of the related image on the medium. The printing apparatus as described. The medium is transported in a predetermined transport direction,
The density correction pattern includes a plurality of patterns having different densities,
The related image includes a plurality of images positioned along the transport direction,
The printing apparatus according to claim 1, wherein the printing unit prints the second print image on the medium such that boundaries between the plurality of patterns in the transport direction coincide with boundaries between the plurality of images. The printing unit has a sublimation type thermal head,
The printing apparatus according to claim 1, wherein the thermal head prints the density correction pattern every time the related image is printed.   5. The printing apparatus according to claim 1, wherein the related image is a slip image indicating slip information when the first print image is printed.   The printing apparatus according to claim 1, wherein the related image is a thumbnail image corresponding to each of the plurality of first print images. A second print image having a different use from the first print image, the second print image including both the related image indicating information related to the printing operation of the first print image and the density correction pattern is printed on the medium. Steps,
Reading the density correction pattern of the second print image printed on the medium;
Calculating a density correction value of the first print image based on the read density correction pattern, and printing the first print image on the medium based on the calculated density correction value;
A printing method.

Images