JP2009202373A - Intermediate transfer printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the line to be detected when a line are formed on the printing surface of an intermediate transfer film. <P>SOLUTION: An intermediate transfer printer includes a line sensor 22 which picturizes the printing surface of the intermediate transfer film 13 which keeps information printed by a thermal head 11, and a poor printing judgement part 2 which detects the presence or absence of the line component of the image of printing surface picturized by the line sensor 22 and judges the quality of printing surface from the detected result. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intermediate transfer printing apparatus that prints information on a booklet or the like, for example.

  2. Description of the Related Art An intermediate transfer type printing apparatus that uses an intermediate transfer film (intermediate transfer material) as one of printing apparatuses that perform printing of a single color or a plurality of colors on a medium such as a booklet is known.

  The printing apparatus includes a printing unit and a transfer unit, and an intermediate transfer film arranged so as to straddle the printing unit and the transfer unit. The printing unit has a thermal head (printing head) and an ink ribbon, and the transfer unit has a heat roller and a backup roller. The intermediate transfer film is stretched over a transport roller and transported.

  At the time of printing, the intermediate transfer film is conveyed to the printing unit, where the thermal head generates heat based on the predetermined information and melts the ink (colorant) of the ink ribbon. The melted ink is transferred to the surface (printing surface) of the intermediate transfer film, and printing information such as characters and images is printed. Then, the intermediate transfer film on which the printing information is printed is conveyed between the heat roller and the backup roller of the transfer section, and at this time, a medium such as a booklet is in a state where the transfer surface faces the intermediate transfer film. It is fed between the heat roller and the backup roller. From this state, the heat roller is rotated, the intermediate transfer film and the medium are pressed against the backup roller and heated, and the print information is transferred to the transfer surface of the medium.

The intermediate transfer film is composed of a long base film and a transfer layer coated on the base film. In the transfer portion, the transfer layer is a medium to be transferred together with print information printed on the transfer layer. (See, for example, Patent Document 1).
JP 2004-74557 A (Page 6, FIG. 1)

  By the way, the above-mentioned thermal head is a line-shaped head that is arranged perpendicularly to the conveyance direction of the intermediate transfer film to be printed, so if it is partially damaged or if dirt is attached, A streak is formed in the transport direction with respect to the printing surface of the transfer film.

  However, conventionally, even if streaks are formed on the printing surface of the intermediate transfer film, streaks cannot be detected, and the streaks are continuously generated until the thermal head is replaced or cleaned. For this reason, there is a problem that if the operator is late in noticing the lines, a large number of defective print media are created.

  In particular, in recent years, security systems such as IC chips are often incorporated into media, and the unit price of the media has increased, so it is not permitted in cost to create a large number of defective print media. It is becoming.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to enable detection of a streak formed on the printing surface of the intermediate transfer material, and to detect a streak SUMMARY OF THE INVENTION An object of the present invention is to provide an intermediate transfer printing apparatus that can skip the transfer of information to a medium.

  In order to solve the above-mentioned problem, the invention according to claim 1 prints information on the intermediate transfer material by a printing unit that melts and transfers the colorant to the printing surface of the intermediate transfer material by a print head, and this printing unit. In the intermediate transfer printing apparatus for transferring the information printed on the intermediate transfer material by thermocompression bonding to the medium by the transfer means, the imaging means for imaging the printing surface of the intermediate transfer material on which the information is printed, and the imaging Determining means for detecting the presence or absence of a linear component of the image captured by the means and determining the quality of the print surface based on the detection result.

  According to the second aspect of the present invention, information is printed on the intermediate transfer material by a printing means that melts and transfers the colorant to the printing surface of the intermediate transfer material with a print head, and is printed on the intermediate transfer material by the printing means. In an intermediate transfer printing apparatus for transferring the information transferred onto the medium by thermocompression bonding using a transfer means, an image pickup means for picking up an image printed on the intermediate transfer material on which the information is printed, and an image picked up by the image pickup means A determination unit that detects the presence or absence of a linear component and determines the quality of the print surface based on the detection result, and the transfer unit determines whether the print surface is in a defective state by the determination unit. And control means for controlling to skip the information transfer operation to the medium.

  According to the present invention, it is possible to prevent creation of a defective print medium.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an intermediate transfer type printing apparatus according to an embodiment of the present invention.

  This intermediate transfer type printing apparatus includes an intermediate transfer unit 1 that forms the center of the apparatus, a print defect determination unit 2 as a determination unit, and a print control unit 3 as a control unit.

  The intermediate transfer unit 1 is a unit that performs intermediate transfer printing.

  The print defect determination unit 2 includes an A / D conversion unit 31, an image memory 32, and an image processing unit (CPU) 33. The print defect determination unit 2 stores a captured image acquired by a line sensor 22 (to be described later) of the intermediate transfer unit 1 in an image memory 32 via an A / D conversion unit 31, and stores the stored captured image as an image processing unit ( CPU) 33 performs analysis as will be described in detail later, and determines whether the printed surface is good or bad (good or bad). In other words, the print defect determination unit 2 determines that a vertical line is not detected on the print surface, as described later, and is defective when a vertical line is detected.

  The print control unit 3 controls the transfer operation based on the determination result of the print defect determination unit 2. That is, if the determination result of the print defect determination unit 2 is good, the transfer operation is performed, and if it is defective, the transfer operation is skipped.

  Further, an alarm device 37 is connected to the print control unit 3 through a control circuit. The print control unit 3 operates the alarm device 37 based on the fact that the print defect determination unit 2 determines that the print is defective a plurality of times, for example, three times continuously, and issues an alarm and operates the printing apparatus. It is supposed to stop.

  FIG. 2 shows the configuration of the intermediate transfer unit 1.

  The intermediate transfer unit 1 includes an information printing unit (hereinafter abbreviated as a printing unit) 1A and an overcoat transfer unit (hereinafter abbreviated as a transfer unit) 1B.

  The printing unit 1A includes a thermal head 11 as a print head, and a molten ink ribbon 14 is opposed to the thermal head 11. Both ends of the molten ink ribbon 14 are wound around a feed roller 14a and a take-up roller 14b. Further, a platen roller 12 is opposed to the thermal head 11 via a molten ink ribbon 14 and an intermediate transfer film 13 as an intermediate transfer material. Both ends of the intermediate transfer film 13 are wound around a feed roller 13a and a take-up roller 13b, and intermediate portions of the intermediate transfer film 13 are stretched over a drive roller 16, a tensioner 17, and guide rollers 23a to 23c.

  In this printing unit 1A, a hot melt transfer printing method is used in which information and the like are printed on the surface of the image receiving and adhesive layer of the intermediate transfer film 13 by the intermediate transfer film 13 and the molten ink ribbon 14. Features of the hot melt transfer method include high image durability and relatively easy application of functional materials to ink materials (for example, fluorescent pigments and aluminum vapor deposited thin films). Suitable for printed materials. As the thermal head 11, a near-edge or corner-edge type line-shaped head arranged perpendicular to the conveyance direction of the intermediate transfer film 13 is used, and it is desirable to perform printing by peeling at the time of heating.

  In general, the driving force for conveying the intermediate transfer film 13 is often provided with a driving mechanism for the platen roller 12, but the friction coefficient between the intermediate transfer film 13 and the platen roller 12 does not increase and is not stable due to hardness and smoothness. There is a case. For this reason, the drive roller 16 described above is provided in the immediate vicinity of the platen roller 12 (on the side of a heat roller 15 described later).

  The intermediate transfer film 13 should have a winding angle as large as possible with respect to the drive roller 16. In the embodiment, the tensioner 17 is arranged so as to obtain a winding angle of 90 ° to 130 °. The tensioner 17 is provided with a spring mechanism (not shown), and tension is applied to the intermediate transfer film 13 within a limited movable range to create a state in which the drive roller 16 and the intermediate transfer film 13 are always in proper contact. The driving roller 16 is rotationally driven by a combination of a five-phase stepping motor, a timing belt, and a speed reduction mechanism using a pulley so that the intermediate transfer film 13 can be accurately conveyed.

  In the vicinity of the intermediate transfer film 13 spanned between the platen roller 12 and the driving roller 16 described above, a line sensor 22 as an image pickup unit is provided in a state of facing and separating. The line sensor 22 scans the printing surface on which the image on the intermediate transfer film 13 is printed based on the conveyance of the intermediate transfer film 13 to acquire a captured image of the printing surface. Note that the imaging method is not limited to a line sensor, and a captured image of a printing surface may be acquired using an area sensor.

  On the other hand, the transfer unit 1B includes a metal heat roller 15 having a flat surface 15a on a part of the circumference, and a backup roller 19 that faces the heat roller 15 with an intermediate transfer film 13 therebetween. The heat roller 15 can be accurately driven at a constant speed by a DC servo motor or a stepping motor. The backup roller 19 is rotatably attached to one end side of the support lever 28. The support lever 28 is rotatably supported at the midway portion, and the other end portion is elastically pressed downward by the coil spring 29. By this depression, the backup roller 19 is pressed against the heat roller 15. A mark detection sensor 20 is provided on the upstream side in the feeding direction of the intermediate transfer film 13 fed between the heat roller 15 and the backup roller 19.

  The transfer unit 1 </ b> B is provided with a transport mechanism 24 for transporting the medium 21 between the heat roller 15 and the backup roller 19. The transport mechanism 24 includes transport roller pairs 25 a to 25 c that sandwich and transport the medium 21, and transport guides 26 a and 26 b that guide the transported medium 21.

  By the way, the rotation of the heat roller 15 is controlled by the print control unit 3 based on the determination result of the print defect determination unit 2 described above. In other words, when the heat roller 15 determines that the print surface on which the image on the intermediate transfer film 13 is printed is good by the print defect determination unit 2, the print information reaches the transfer start position. The transfer operation is started by rotating the intermediate transfer film 13 against the medium 21 while being rotated at the timing.

  On the other hand, when it is determined by the print defect determination unit 2 that the print surface on which the image on the intermediate transfer film 13 has been printed is defective, the heat roller 15 may have the print information reach the transfer start position. Without being rotated, the flat surface 15a is kept in a state of being opposed to and separated from the backup roller 19. That is, the intermediate transfer film 13 is conveyed without being pressed against the medium 21. That is, when the printing surface on which the image on the intermediate transfer film 13 is printed is defective, the operation of transferring the printing surface to the booklet is skipped.

  Next, the print transfer operation of the intermediate transfer printing apparatus configured as described above will be described with reference to FIGS.

  When an instruction to start printing is issued (step 1 in FIG. 3), the intermediate transfer film 13 is fed out from the feed roller 13a and the medium 21 is taken in (step 2). The intermediate transfer film 13 that has been fed out has its hologram position mark detected by the mark detection sensor 18, and is positioned and controlled to the print start position based on the detection result. From this state, the thermal head 11 generates heat based on the print information, and unique print information or the like is printed at a predetermined position on the intermediate transfer film 13. This printed information is color printing by superimposing four colors of black in addition to the three primary colors of Y, M, and C. These multi-color overlay printing is performed by the intermediate transfer film 13 reciprocating the thermal head 11 as many times as the number of colors. In addition, the information to be printed is a reverse image. In addition to the above four colors, a functional ink such as an ink containing a fluorescent pigment may be applied as the printing color.

  The intermediate transfer film 13 to which the printing information is given by the printing unit 1A is wound up in the forward direction, and a print image of the intermediate transfer film 13 is captured by the line sensor 22 in the middle of the path (step 3). The captured image is transmitted to the image memory 32 via the A / D conversion unit 31 of the print defect determination unit 2. The image transmitted to the image memory 32 is subjected to image processing by the CPU 33 as shown below, and its quality is determined.

That is, the print defect determination unit 2 performs spatial filtering processing to smooth the image and reduce noise, or to differentiate the image and extract an edge. As shown in FIG. 6 (a), spatial filtering is performed when the original image is f (i, j) and the 3 × 3 filter is w (x, y) as shown in FIG. 6 (b). The image g (i, j) is obtained by the following equation 1.

  The image is differentiated to detect the edge component, but prior to that, the original image is smoothed to reduce the noise of the image (step 4). For image smoothing, a spatial filtering process using a 3 × 3 smoothing operator shown in FIG. 6C is performed. Subsequently, the image is subjected to lateral differentiation to detect vertical edge components (step 5). For the detection of the edge component, first-order differentiation using a 3 × 3 Sobel operator shown in FIG. 6D is generally used.

When the differential image is binarized (step 6), only the vertical component of the edge is obtained. For binarization, binarization with a fixed threshold is sufficient if sufficient contrast is obtained, but a threshold calculation method such as Otsu's method may be used. Straight line detection using the Hough transform is performed on the extracted vertical edge component (step 7). The Hough transform detects a straight line as follows. First, the point group in the XY original image is converted into a Hough curve group on the θ-ρ parameter plane, and the cell counter of the Hough curve locus is incremented by one. When the point of the original image is (X, Y), the Hough curve is given by Equation 2. Since the detection target is almost limited to the vertical line, θ may be calculated in the range of 0 ± 5 °.

  Next, the intersection of the Hough curve group is obtained on the θ-ρ parameter plane. Specifically, the coordinates (θs, ρs) of the cell where the counter is maximized are obtained.

The straight line to be obtained is given by the following equation 3.

  It is confirmed whether a straight line exists on the calculated linear equation. For example, an edge image is scanned in a range of ± 4 with respect to the X coordinate obtained by Expression 3, and for example, if there are two or more pixels and one pixel, it is determined that the pixel is on a straight line. Such a determination is performed on all the Y coordinates. For example, when 90% or more exists on a straight line, it is determined that a straight line (vertical stripe) exists (step 8).

  If it is determined that the print information printed on the intermediate transfer film 13 is defective by the above processing (step 9), the print on which the image on the intermediate transfer film 13 determined to be defective is printed. Even when the surface reaches the transfer start position, the heat roller 15 is not rotated, and the flat surface 15a is kept facing the backup roller 19 while being separated. Thereby, the printing surface on which the image on the intermediate transfer film 13 is printed is conveyed to the transfer unit 1B together with the medium 21 without being pressed against the medium 21, that is, the transfer operation is skipped. The intermediate transfer film 13 is wound up while the printing surface on which the image on the intermediate transfer film 13 is printed remains untransferred (step 10). The untransferred medium 21 is discharged as it is (step 11). This untransferred medium 21 can be reused.

  In addition, when the print information printed on the intermediate transfer film 13 is determined to be defective by the print defect determination unit 2 a plurality of times, for example, three times continuously, the alarm device 37 is activated by the print control unit 3. Then, an alarm is issued and the operation of the printing apparatus is stopped.

  On the other hand, if it is determined in step 9 that there are no vertical stripes, that is, if it is determined that the line is good, the intermediate transfer film 13 to which the printing information is applied is wound in the forward direction (the direction of the heat roller 15). The position is detected by the mark detection sensor 20 in the middle of the route. Based on the detection result, the intermediate transfer film 13 is sent to the transfer start position.

  On the other hand, the medium 21 is taken in and conveyed as shown in FIG. 4A, and is positioned with respect to the heat roller 15 as shown in FIG. 4B. After this positioning, the intermediate transfer film 13 and the medium 21 are overlapped with the rotation of the heat roller 15, and are pressurized and heated simultaneously with the conveyance as shown in FIG. Thereafter, as shown in FIG. 5, the base layer 35a of the intermediate transfer film 13 is pulled up at an angle of 60 ° to 110 ° with respect to the medium 21, and print information (ink as a colorant) 35b and an image receiving / adhesive layer 35c. Then, the transfer of the hologram layer 35d is completed (step 12). The medium 21 on which the transfer is completed is discharged as it is as shown in FIG. 4C (step 13) or is transported to the next mechanism section.

  As described above, according to this embodiment, the image printed on the printing surface of the intermediate transfer film 13 is analyzed to detect the presence or absence of linear components, and the quality of the printing surface is determined based on the detection result. Therefore, when the printing surface is defective, the image transfer to the medium 21 can be skipped.

  Therefore, even when the thermal head 11 is partially damaged or dirty, even if a streak-like print defect occurs on the print surface, it is not transferred to the medium 21 and the print defect medium It becomes possible to prevent creation.

Further, when the print information printed on the intermediate transfer film 13 is determined to be defective multiple times, for example, three times continuously, by the print defect determination unit 2, the alarm device 37 is operated to issue an alarm. Since the printing apparatus is stopped, it is possible to avoid the production of a large amount of defective print media.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above. Furthermore, you may combine the component covering different embodiment suitably.

1 is a block diagram illustrating a configuration of a printing apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating an intermediate transfer unit of the printing apparatus of FIG. FIG. 3 is a flowchart showing a print transfer operation of an intermediate transfer unit in FIG. 2. The figure which shows conveyance of the medium in a transfer part of FIG. 2, and operation | movement of a heat roller. The figure which expands and shows the image transfer state of FIG. The figure for demonstrating the spatial filtering process of the printing defect determination part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Intermediate transfer part, 2 ... Print defect determination part (determination means), 3 ... Print control part (control means), 11 ... Thermal head (print head), 13 ... Intermediate transfer film (intermediate transfer material), 15 ... Heat roller (transfer means), 21... Medium, 22... Line sensor (imaging means), 35 b .. ink (colorant), 37.

Claims (4)

Information is printed on the intermediate transfer material by a printing means that melts and transfers the colorant to the printing surface of the intermediate transfer material by a print head, and the information printed on the intermediate transfer material by this printing means is transferred to the medium. In the intermediate transfer printing device that transfers by thermocompression bonding with
Imaging means for imaging the printing surface of the intermediate transfer material on which the information is printed;
An intermediate transfer printing apparatus comprising: a determination unit that detects the presence or absence of a linear component of an image captured by the imaging unit and determines the quality of the print surface based on the detection result. Information is printed on the intermediate transfer material by a printing means that melts and transfers the colorant to the printing surface of the intermediate transfer material by a print head, and the information printed on the intermediate transfer material by this printing means is transferred to the medium. In the intermediate transfer printing device that transfers by thermocompression bonding with
Imaging means for imaging the printing surface of the intermediate transfer material on which the information is printed;
A determination unit that detects the presence or absence of a linear component of the image captured by the imaging unit and determines the quality of the print surface based on the detection result;
And a control means for controlling the transfer means to skip the information transfer operation to the medium based on the determination that the printing surface is in a defective state. Transfer printing device.   3. The intermediate transfer printing apparatus according to claim 1, wherein the operation is stopped when the determination of the defect of the print surface by the determination unit is continued a plurality of times.   4. The intermediate transfer printing apparatus according to claim 1, wherein the determination unit detects a linear component of the image by edge detection and Hough transform of the image. 5.

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