JP2012192545A - Image forming apparatus and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can form an image appropriately even on a novel recording medium the relationship between the tension and the elongation amount of that is unknown.SOLUTION: The image forming apparatus includes a conveyance section that conveys a long recording medium, an image forming section that forms an image, a tension control section that controls the tension applied to the recording medium during conveyance, an image capturing section that captures an image formed on the recording medium by the image forming section, and a main control section performing arithmetic processing. The image forming section forms the image of a predetermined pattern by controlling so that a first tension is applied to the recording medium (step S101, 102), the image capturing section acquires a first distance from the first image data in a state where the first tension is applied to the recording medium (step S103), the image capturing section acquires a second distance from the second image data in a state where the second tension is applied to the recording medium (step S105, 106), and then the relationship between the tension applied to the recording medium and the elongation amount thereof is operated from the first and second distances (step S107).

Description

  The present invention relates to an image forming apparatus and an image forming method for forming an image while applying a predetermined tension to a long recording medium.

  An ink jet printer is known as one of image forming apparatuses. This ink jet printer performs printing by ejecting ink as a liquid from a plurality of nozzles of a head toward various media such as paper, cloth, and film.

  Among the ink jet printers, there is a type that uses a large paper having a paper size of A2 or larger. In such large-format ink jet printers, so-called roll paper (hereinafter, a so-called roll paper around which the paper is wound is used as a roll body and a portion pulled out from the roll body is used as paper) is used in addition to the cut sheet paper. There are many cases.

  In addition, in an ink jet printer, a roll-shaped resin film is used as a recording medium, and further, UV ink is used as an ink to be sprayed on the resin film, so that it is attached to a package such as food. One that prints labels is also known.

For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2003-118136), a printing tape is fed along a tape feeding path (conveying path), and ink (liquid) is applied to the printing tape in a printing area in the middle of the tape feeding path. ) Is ejected, and the printed printing tape is naturally dried in a drying area in the middle of the tape feed path, and then the naturally dried printing tape is wound up.
JP 2003-118136 A

  When forming an image on an elongated recording medium drawn out from a roll body by an ink jet method, a certain amount of tension is applied to the recording medium to eject ink droplets. When a thin synthetic resin film is used as a recording medium and ink is ejected onto such a film to form an image, the recording medium is stretched by the applied tension during image formation. The ink ejection timing must be controlled in consideration of the fact that the recording medium shrinks when released.

  Accordingly, it is conceivable to store the tension applied to the recording medium and the relationship between the amount of elongation of the recording medium in accordance with the type of the recording medium and control the ink ejection timing based on this. When a new type is used, there is a problem that it cannot be handled because there is no stored information as described above.

SUMMARY An advantage of some aspects of the invention is that an image forming apparatus according to the present invention includes a conveyance unit that conveys a long recording medium, and an image that is recorded on the recording medium that is conveyed by the conveyance unit. An image forming unit for forming, a tension control unit for controlling a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit, and an image formed on the recording medium by the image forming unit A main control unit that controls the imaging unit, the transport unit, the image forming unit, the tension control unit, and the imaging unit, and that performs arithmetic processing; The tension control unit controls the recording medium to apply a first tension, the image forming unit forms an image of a predetermined pattern, and the first tension is applied to the recording medium. The image unit captures the first image data according to the predetermined pattern, acquires the first distance from the first image data, stops the conveyance of the recording medium by the conveyance unit, and is different from the first tension. In a state where two tensions are applied to the recording medium, the imaging unit images the second image data according to the predetermined pattern, acquires a second distance from the second image data, and obtains the first distance and the second distance. From the distance, a relational expression of tension and elongation applied to the recording medium is calculated.

  The image forming apparatus according to the present invention includes a transport unit that transports a long recording medium, an image forming unit that forms an image on the recording medium transported by the transport unit, and the transport unit. A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium, an imaging unit that captures an image formed on the recording medium by the image forming unit, the conveyance unit, and the image And a main control unit that controls the forming unit, the tension control unit, and the imaging unit and that performs arithmetic processing. The main control unit is connected to the recording medium by the tension control unit. Control is performed so that tension is applied, and an image of a predetermined pattern is formed by the image forming unit, and the first pattern is applied to the recording medium by the imaging unit in a state where the first tension is applied to the recording medium. The first image data is imaged, the first distance is acquired from the first image data, the second tension is applied to the recording medium by the tension control unit, and a predetermined pattern is formed by the image forming unit. An image is formed, the image pickup unit picks up the second image data according to the predetermined pattern in a state where the second tension is applied to the recording medium, acquires a first distance from the second image data, and A relational expression of tension and elongation applied to the recording medium is calculated from the one distance and the second distance.

  The image forming apparatus according to the present invention also includes a transport unit that includes a rotatable drum roller that transports a long recording medium, and the recording medium that is wound around the drum roller and transported. An image forming unit for forming, a tension control unit for controlling a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit, and an image formed on the recording medium by the image forming unit A main control unit that controls the imaging unit, the transport unit, the image forming unit, the tension control unit, and the imaging unit, and that performs arithmetic processing; The tension control unit controls the recording medium to apply a first tension, the image forming unit forms an image of a predetermined pattern, and the first tension is applied to the recording medium. In this state, the imaging unit captures the first image data according to the predetermined pattern, acquires a first position from the first image data, stops the conveyance of the recording medium by the conveyance unit, and In a state where a second tension different from the tension is applied to the recording medium, the imaging unit captures the predetermined pattern, acquires second image data, acquires a second position from the second image data, and acquires the first position. A relational expression of tension and elongation applied to the recording medium is calculated from the position and the second position.

The image forming apparatus according to the present invention also includes a transport unit that includes a rotatable drum roller that transports a long recording medium, and the recording medium that is wound around the drum roller and transported. An image forming unit for forming, a tension control unit for controlling a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit, and an image formed on the recording medium by the image forming unit A main control unit that controls the imaging unit, the transport unit, the image forming unit, the tension control unit, and the imaging unit, and that performs arithmetic processing; The tension control unit controls the recording medium to apply a first tension, the image forming unit forms an image of a predetermined pattern, and the first tension is applied to the recording medium. In this state, the imaging unit captures the first image data according to the predetermined pattern, acquires a first distance from the first image data, and the tension control unit applies a second tension to the recording medium. The image forming unit forms an image of the predetermined pattern, and the second image data of the predetermined pattern is imaged by the imaging unit in a state where the second tension is applied to the recording medium. A second distance is acquired from two image data, and a relational expression between tension and elongation applied to the recording medium is calculated from the first distance and the second distance.

  The image forming apparatus according to the present invention includes a transport unit that transports a long recording medium, an image forming unit that forms an image on the recording medium transported by the transport unit, and the transport A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the unit, an imaging unit that captures an image formed on the recording medium by the image forming unit, the conveyance unit, A main control unit that controls the image forming unit, the tension control unit, and the imaging unit, and that performs arithmetic processing; and the main control unit is connected to the recording medium by the tension control unit. A step of forming an image of a predetermined pattern by the image forming unit by controlling so that one tension is applied, and the imaging unit by the imaging unit in a state where the first tension is applied to the recording medium. Capturing the first image data related to the pattern, obtaining the first distance from the first image data, stopping the conveyance of the recording medium by the conveyance unit, and a second tension different from the first tension is Imaging the second image data according to the predetermined pattern with the imaging unit in a state of being applied to a recording medium, obtaining a second distance from the second image data, and the first distance and the second distance. And calculating a relational expression between tension and elongation applied to the recording medium.

  The image forming apparatus according to the present invention includes a transport unit that transports a long recording medium, an image forming unit that forms an image on the recording medium transported by the transport unit, and the transport A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the unit, an imaging unit that captures an image formed on the recording medium by the image forming unit, the conveyance unit, A main control unit that controls the image forming unit, the tension control unit, and the imaging unit, and that performs arithmetic processing; and the main control unit is connected to the recording medium by the tension control unit. A step of forming an image of a predetermined pattern by the image forming unit by controlling so that one tension is applied, and the imaging unit by the imaging unit in a state where the first tension is applied to the recording medium. Imaging the first image data relating to the pattern, obtaining a first distance from the first image data, and controlling the second tension to be applied to the recording medium by the tension control unit to form the image Forming an image of a predetermined pattern by the unit, and capturing an image of the second image data according to the predetermined pattern by the imaging unit in a state where the second tension is applied to the recording medium. A step of obtaining a distance; and a step of calculating a relational expression of tension and elongation applied to the recording medium from the first distance and the second distance.

  The image forming apparatus according to the present invention also includes a transport unit including a rotatable drum roller for transporting a long recording medium, and an image for the recording medium wound around the drum roller and transported. An image forming unit that forms the image, a tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit, and an image formed on the recording medium by the image forming unit A main control unit that controls the image pickup unit, the transport unit, the image forming unit, the tension control unit, and the image pickup unit, and performs arithmetic processing. Controlling the first tension to be applied to the recording medium by the tension control unit and forming an image of a predetermined pattern by the image forming unit; and The image capturing unit captures the first image data related to the predetermined pattern in a state of being applied to the recording medium, acquires a first position from the first image data, and transports the recording medium by the transport unit. In a state where the second tension different from the first tension is applied to the recording medium, the imaging unit captures the predetermined pattern to acquire the second image data, and the second position is determined from the second image data. A step of obtaining, and a step of calculating a relational expression of tension and elongation applied to the recording medium from the first position and the second position.

  The image forming apparatus according to the present invention also includes a transport unit including a rotatable drum roller for transporting a long recording medium, and an image for the recording medium wound around the drum roller and transported. An image forming unit that forms the image, a tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit, and an image formed on the recording medium by the image forming unit A main control unit that controls the image pickup unit, the transport unit, the image forming unit, the tension control unit, and the image pickup unit, and performs arithmetic processing. Controlling the first tension to be applied to the recording medium by the tension control unit and forming an image of a predetermined pattern by the image forming unit; and The first image data related to the predetermined pattern is imaged by the imaging unit in a state of being applied to the recording medium, and a first distance is obtained from the first image data; Controlling the second tension to be applied and forming an image of the predetermined pattern by the image forming unit; and the second relating to the predetermined pattern by the imaging unit while the second tension is applied to the recording medium. Capturing image data and obtaining a second distance from the second image data; calculating a relational expression of tension and elongation applied to the recording medium from the first distance and the second distance; , Is executed.

  As described above, according to the image forming apparatus and the image forming method of the present invention, the relational expression between the tension and the amount of elongation applied to the recording medium can be calculated, so that the new recording in which the relationship between the tension and the amount of elongation is unknown. Also for the medium, it is possible to control the ink ejection timing, and it is possible to appropriately form an image.

1 is a diagram illustrating a main part of an image forming apparatus 10 according to an embodiment of the present invention. 1 is a block diagram of the overall configuration of a printer. FIG. 6 is a diagram illustrating a flowchart of processing for obtaining a relationship between tension and elongation applied to the recording medium S of the image forming apparatus 10 according to the embodiment of the present invention. 6 is a diagram illustrating an example of a test pattern imaged by an imaging unit 90. FIG. It is a figure which shows the relationship between the tension | tensile_strength applied to a recording medium, and the elongation amount of a recording medium. FIG. 10 is a diagram illustrating a flowchart of processing for obtaining a relationship between tension and elongation applied to a recording medium S of an image forming apparatus 10 according to a second embodiment of the present invention. It is a figure which shows the principal part of the image forming apparatus 10 which concerns on 3rd Embodiment of this invention. FIG. 10 is a diagram illustrating a flowchart of processing for obtaining a relationship between tension and elongation applied to a recording medium S of an image forming apparatus according to a third embodiment. 6 is a diagram illustrating an example of a test pattern imaged by an imaging unit 90. FIG. It is a figure which shows the relationship between the tension | tensile_strength applied to a recording medium, and the elongation amount of a recording medium.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a main part of an image forming apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a block diagram of the overall configuration of the printer 10. In the present embodiment, the line head unit 150 is arranged so as to cover the entire sheet width in the direction perpendicular to the recording medium conveyance direction in the middle of the recording sheet conveyance path without moving along the recording sheet conveyance plane. Is used. A nozzle row (not shown) that ejects ink is provided on the lower surface of the line head unit 150 in a direction orthogonal to the conveyance direction of the recording medium, thereby ejecting ink to form an image on the recording medium. . The line head unit 150 is connected to the main control unit 110 and the drive signal generation circuit 117. A drive voltage for controlling the ejection of ink is sent from the drive signal generation circuit 117 to each nozzle of the line head unit 150.

  As the line head unit 150 as described above, in this embodiment, 220Y that jets color ink (liquid) of each color of yellow (Y), magenta (M), cyan (C), and black (K) to the recording medium S. , 220M, 220C, and 220K are installed, and a full-color image can be printed on the recording medium S. In the following, yellow or yellow ink is abbreviated as “Y” or the like, and may be added to the reference numeral as a suffix to indicate the color of the liquid ejected by the line head unit 150. In the present embodiment, a configuration is described in which four line heads that eject four colors of ink of yellow (Y), magenta (M), cyan (C), and black (K) are provided. The color types and the number of colors that can be handled by the printer 10 are not limited thereto.

  The computer 1 sends image data corresponding to an image to be printed to the printer 10 via a printer driver. The image data includes pixel data indicating whether or not ink is ejected for each ink color for each pixel of the medium.

  The ink used in the present embodiment is an ultraviolet curable UV ink that cures when irradiated with ultraviolet rays. As the ultraviolet curable ink, a radical polymerization ink containing a radical polymerizable compound, a cationic polymerization ink containing a cationic polymerizable compound, and a radical polymerization ink and a cationic polymerization ink were combined as a polymerizable compound. Hybrid ink is applicable. The ink includes a polymerizable compound that is polymerized and cured with light other than ultraviolet light, and a photoinitiator that initiates a polymerization reaction between the polymerizable compounds with light other than ultraviolet light, such as electron beams, X-rays, and infrared light. May be applied.

  The recording medium S used in the printer 10 according to the present invention is a recording medium S made of various papers such as plain paper, recycled paper, glossy paper, various fabrics, various non-woven fabrics, resin, metal, glass and the like. Although applicable, in this embodiment, a transparent or translucent non-absorbent resin film used for so-called soft packaging is particularly preferably used.

  When the resin film as the recording medium S is a transparent or translucent medium, not only front printing but also back printing is possible. As the resin for the resin film, PET (polyethylene terephthalate), PS (polyester), PP (polypropylene), or the like is preferably used.

  The head unit 150 as described above is connected to the main control unit 110, and a signal for controlling ink ejection is transmitted to the head unit 150. The lower part of the line head unit 150 is a recording area for recording on the recording medium S, and a platen 19 for horizontally supporting the recording medium S from the non-recording surface side is provided in this recording area.

  In the image forming apparatus 10, the conveyance path of the recording medium S is configured by the supply roller 20, the first conveyance roller 41, the drive roller pair 30, the second conveyance roller 42, the tension roller pair 70, the take-up roller 80, and the like. Has been.

  The driving roller pair 30 and the take-up roller 80 are provided with a motor (not shown) attached to these roller shafts and a recording medium conveyance control unit 130 that controls the motor, so that the recording medium S is conveyed and taken up. Etc. are to be controlled. The recording medium conveyance control unit 130 is connected to a controller 110 which is a host device. Based on an instruction from the controller 110, the recording medium S is conveyed and the recording medium S is taken up by the take-up roller 80. It comes to control.

  Further, the tension roller pair 70 can control the tension applied to the recording medium S by a motor (not shown) attached to the roller shaft and a tension roller control unit 170 that controls the motor. ing. The tension roller control unit 170 is connected to a controller 110 which is a host device, and controls the conveyance of the recording medium S and the tension roller pair 70 based on a command from the controller 110.

  The supply roller 20 sends out the long recording medium S to the conveyance path. The recording medium S sent out from the supply roller 20 is ejected with ink at the image forming section in the platen 19 section, the ink on the recording medium S is cured by the ultraviolet irradiation unit 160, and finally printed by the take-up roller 80. The recording medium S is wound up.

  The first transport roller 41 and the second transport roller 42 in the transport path are driven rollers, and among these, the second transport roller 42 is provided with a tension sensor 60. The tension sensor 60 transmits the detected tension value to the main control unit 110 that is a host device.

  The take-up roller 80 is provided with a pressing roller 45 that prevents the recording medium S from being caught by pressing the recording medium S against the roll body when the recording medium S is wound around the roll body.

  Further, on the upper surface (not shown) of the casing of the image forming apparatus 10, for example, a touch panel is displayed, and a recording mode that can be selected by the user is displayed, and an input operation in which the user selects and inputs the displayed recording mode. A unit 120 is provided. The input operation unit 120 is connected to a main control unit 110 described later, and outputs a signal related to a recording mode selected based on a predetermined operation to the main control unit 110. In the present invention, when the image forming apparatus 10 is to perform processing for obtaining the relationship between the tension applied to the recording medium S and the amount of elongation, a processing request can be received from such an input operation unit 120. .

  FIG. 2 shows a control block for controlling the image forming apparatus 10 according to the present embodiment. The main control unit 110 in this control block includes, for example, a CPU 111, a ROM 112, and a RAM 113, and is recorded in the ROM 112. The processing program is developed in the RAM 113 and executed by the CPU 111, or predetermined arithmetic processing is executed. The interface 105 is an interface provided to connect the main control unit 110 of the image forming apparatus 10 and the computer 1. The ROM 112 stores data for printing a test pattern, which will be described later, or a program for executing processing for obtaining the relationship between the tension applied to the recording medium S and the amount of elongation.

  In accordance with the processing program described above, the main control unit 110 controls the recording medium conveyance control unit 130, the line head unit 150, the ultraviolet irradiation unit 160, the tension roller control unit 170, the imaging unit 90, and the like based on the status such as the operation status. It comes to control.

The ultraviolet irradiation unit 160 is a device for irradiating the UV ink ejected onto the recording medium with ultraviolet rays to cure the UV ink. The light source of the ultraviolet irradiation unit 160 includes, for example, a UV-LED (Ultra Violet Light Emitting Diode) that generates ultraviolet rays. The ultraviolet irradiation rate can be controlled by the control from the main control unit 110. By doing so, it is possible to change the amount of ultraviolet irradiation at each position of the recording medium S. In addition, a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low pressure mercury lamp, a high pressure mercury lamp, etc. can be used as the light source.

  Further, the imaging unit 90 is configured so as to be able to capture an image of the printing surface of the recording medium S, and can be configured by, for example, a CCD camera. The image data picked up by the image pickup unit 90 is transmitted to the main control unit 110 and is analyzed by the main control unit 110 so that the distance between the test patterns printed on the recording medium S or the test pattern The amount of displacement can be grasped.

  Processing for obtaining the relationship between the tension applied to the recording medium S and the elongation amount, which is executed by the image forming apparatus 10 configured as described above, will be described. Such processing is executed to control the ink ejection timing for a new recording medium in which the relationship between tension and elongation is unknown. Thus, by obtaining the relationship between the tension applied to the recording medium S and the amount of elongation, the image forming apparatus 10 according to the present invention can control the ink ejection timing even for a new recording medium. Thus, an image can be appropriately formed.

  FIG. 3 is a flowchart of processing for obtaining the relationship between the tension and the amount of elongation applied to the recording medium S of the image forming apparatus according to the embodiment of the present invention.

When the processing is started in step S100, in the subsequent step S101, the tension roller control unit is configured so that the tension of the recording medium S being conveyed becomes the first tension (T ₁ ) based on the detection data of the tension sensor 60. Control is performed at 170.

  In the next step S102, a test pattern is printed by the line head unit 150K. Here, as the test pattern to be used, two lines extending in the width direction of the recording medium S and having a predetermined interval can be used. Note that the test pattern is printed by the line head unit 150K because the image data acquired by the imaging unit 90 can be easily analyzed. However, it is also possible to configure the test pattern to be printed by the line head unit 150 that ejects ink of other colors.

In step S103, a test pattern is imaged (imaging the first image data) by the imaging unit 90 in a state where the tension of the recording medium S is maintained at the first tension (T ₁ ), and this is used as the main control unit 110. The distance g ₁ between the patterns is obtained by analyzing the image at.
FIG. 4A shows the image data captured in this step.

  Next, in step S <b> 104, the drive roller pair 30 is stopped by the print medium conveyance control unit 130, and the print medium S is sandwiched and fixed at the nip of the drive roller pair 30.

In subsequent step S105, based on the detection data of the tension sensor 60, the tension roller control unit 170 performs control so that the tension of the recording medium S becomes the second tension (T ₂ ). In the present embodiment, the case where the second tension (T ₂ )> the first tension (T ₁ ) is described, but the second tension (T ₂ ) is made smaller than the first tension (T ₁ ). May be.

In step S106, a test pattern is imaged by the imaging unit 90 (imaging second image data) while the tension of the recording medium S is maintained at the second tension (T ₂ ), and the inter-pattern distance g ₂ is set. get. FIG. 4B shows the image data captured in this step.

In step S107, a relational expression between the tension and the amount of elongation of the recording medium is calculated from the distance g ₁ corresponding to the first tension (T ₁ ) and the distance g ₂ corresponding to the second tension (T ₂ ). FIG. 5 is a diagram showing the relationship between the tension applied to the recording medium S and the amount of elongation of the recording medium S. As shown in FIG. 5, it is assumed that there is a linear proportional relationship between the tension of the recording medium S and the amount of elongation of the recording medium S.

  That is, the following expression (1) is established with a and b as unknown constants.

（１）からａ、ｂを求め、記録媒体Ｓにかけられるテンションｘと、そのときの伸び量ｙとの間には下式（２）の関係があることを求めることができる。

From (1), a and b are obtained, and it can be obtained that there is a relationship of the following expression (2) between the tension x applied to the recording medium S and the elongation amount y at that time.

このように記録媒体Ｓにかかるテンションと伸び量の関係を求め、ステップＳ１０８で処理を終了する。

In this way, the relationship between the tension applied to the recording medium S and the amount of elongation is obtained, and the process ends in step S108.

  As described above, according to the image forming apparatus 10 of the present invention, the relational expression between the tension and the elongation amount applied to the recording medium S can be calculated. Also for the recording medium S, printing can be performed by controlling the ink ejection timing, and an image can be formed appropriately.

  Next, another embodiment of the present invention will be described. This embodiment is different from the previous embodiment only in the processing algorithm for obtaining the relationship between the tension applied to the recording medium S and the amount of elongation, and the configuration of the apparatus does not change. Therefore, this algorithm will be described below. To do. FIG. 6 is a flowchart of processing for obtaining the relationship between the tension and the amount of elongation applied to the recording medium S of the image forming apparatus 10 according to the second embodiment of the present invention.

In FIG. 6, when the process is started in step S200, in the subsequent step S201, based on the detection data of the tension sensor 60, the tension of the recording medium S being conveyed becomes the first tension (T ₁ ). Control is performed by a tension roller control unit 170.

  In the next step S202, a test pattern is printed by the line head unit 150K. Here, as the test pattern to be used, two lines extending in the width direction of the recording medium S and having a predetermined interval can be used. As in the previous embodiment, the line head unit 150 for printing the test pattern may be other than the line head unit 150K.

In step S203, a test pattern is imaged (imaging the first image data) by the imaging unit 90 in a state where the tension of the recording medium S is maintained at the first tension (T ₁ ), and this is used as the main control unit 110. The distance g ₁ between the patterns is obtained by analyzing the image at.
FIG. 4A shows the image data captured in this step.

In the next step S204, based on the detection data of the tension sensor 60, the tension roller control unit 170 controls so that the tension of the recording medium S being conveyed becomes the second tension (T ₂ ).

  In the next step S205, a test pattern is printed by the line head unit 150K.

In step S206, the test pattern is imaged by the imaging unit 90 (second image data is imaged) while the tension of the recording medium S is maintained at the second tension (T ₂ ), and the inter-pattern distance g ₂ is set. get. FIG. 4B shows the image data captured in this step.

In step S207, a relational expression between the tension and the elongation amount of the recording medium is calculated from the distance g ₁ corresponding to the first tension (T ₁ ) and the distance g ₂ corresponding to the second tension (T ₂ ). Also in this embodiment, as shown in FIG. 5, it can be assumed that there is a linear proportional relationship between the tension of the recording medium S and the amount of elongation of the recording medium S.

  Also in the present embodiment, the relationship between the tension applied to the recording medium S and the amount of elongation can be obtained as shown in Expression (2). In step S208, the process ends.

  As described above, according to the image forming apparatus 10 according to the second embodiment, it is possible to calculate the relational expression between the tension applied to the recording medium S and the extension amount, and thus the relationship between the tension and the extension amount is unknown. Even for a certain new recording medium S, printing can be performed by controlling the ejection timing of ink, and an image can be appropriately formed.

  Next, another embodiment of the present invention will be described. FIG. 7 is a view showing a main part of the image forming apparatus 10 according to the third embodiment of the present invention.

  A configuration of the image forming apparatus 10 used in the third embodiment will be described. In the first and second embodiments, the recording medium S is conveyed on the platen 19 and ink is ejected by the line head unit 150 to form an image on the recording medium S. On the other hand, in the present embodiment, the recording medium S is wound around the drum roller 50 having a relatively large roller diameter and configured to be rotatable, and is conveyed to the recording medium S wound around the drum roller 50. On the other hand, the line head unit 150 ejects ink to form an image on the recording medium S.

  When the recording medium S is wound around such a drum roller 50, the first pressing roller 43 presses the recording medium S against the drum roller 50 so that winding disturbance does not occur.

  In the present embodiment, when the nip in the drive roller pair 30 is P and the nip formed by the drum roller 50 and the first pressing roller 43 is Q, the distance between the PQs is L. . The block diagram of the image forming apparatus 10 is the same as that of the previous embodiment.

  A method for obtaining the relationship between tension and elongation in the image forming apparatus 10 according to the third embodiment configured as described above will be described.

  FIG. 8 is a flowchart of a process for obtaining the relationship between tension and elongation applied to the recording medium S of the image forming apparatus according to the third embodiment of the present invention.

When the process is started in step S300, in the subsequent step S301, the tension roller control unit is configured so that the tension of the recording medium S being conveyed becomes the first tension (T ₁ ) based on the detection data of the tension sensor 60. Control is performed at 170.

  In the next step S302, a test pattern is printed by the line head unit 150K. Here, as a test pattern to be used, a single line or the like extending in the width direction of the recording medium S can be used. Note that the test pattern is printed by the line head unit 150K because the image data acquired by the imaging unit 90 can be easily analyzed. However, it is also possible to configure the test pattern to be printed by the line head unit 150 that ejects ink of other colors.

In step S303, the test pattern is imaged (acquisition of the first image data) by the imaging unit 90 in a state where the tension of the recording medium S is maintained at the first tension (T ₁ ), as shown in FIG. The position (A) of the test pattern is acquired.

  Next, in step S <b> 304, the drive roller pair 30 is stopped by the print medium conveyance control unit 130, and the print medium S is sandwiched and fixed at the nip of the drive roller pair 30.

In subsequent step S305, based on the detection data of the tension sensor 60, the tension roller control unit 170 performs control so that the tension of the recording medium S becomes the second tension (T ₂ ). In the present embodiment, the case where the second tension (T ₂ )> the first tension (T ₁ ) is described, but the second tension (T ₂ ) is made smaller than the first tension (T ₁ ). May be.

In step S306, the test pattern is imaged (acquisition of second image data) by the imaging unit 90 in a state where the tension of the recording medium S is maintained at the second tension (T ₂ ), as shown in FIG. The position (B) of the test pattern is acquired.

In step S307, a relational expression between the tension and the amount of elongation of the recording medium is calculated from the position (A) corresponding to the first tension (T ₁ ) and the position (B) corresponding to the second tension (T ₂ ). .

  FIG. 10 is a diagram illustrating the relationship between the tension applied to the recording medium S and the amount of elongation of the recording medium S. As shown in FIG. 10, it is assumed that there is a linear proportional relationship between the tension of the recording medium S and the amount of elongation of the recording medium S.

In the present embodiment, when the first tension (T ₁ ) is changed to the second tension (T ₂ ), the test pattern is displaced from the position (A) to the position (B). This is due to the elongation of the recording medium S. This is because the recording medium S wound around the drum roller 50 does not expand or contract.

  Assuming that the displacement amount from the position (A) to the position (B) is d, the following expression (3) is established with a and b as unknown constants.

（３）からａ、ｂを求め、記録媒体Ｓにかけられるテンションｘと、そのときの伸び量ｙとの間には下式（４）の関係があることを求めることができる。

From (3), a and b are obtained, and it can be obtained that there is a relationship of the following equation (4) between the tension x applied to the recording medium S and the amount of elongation y at that time.

このように記録媒体Ｓにかかるテンションと伸び量の関係を求め、ステップＳ３０８で処理を終了する。

In this manner, the relationship between the tension applied to the recording medium S and the amount of elongation is obtained, and the process ends in step S308.

  As described above, according to the image forming apparatus 10 according to the third embodiment, it is possible to calculate the relational expression between the tension applied to the recording medium S and the extension amount, and thus the relationship between the tension and the extension amount is unknown. Even for a certain new recording medium S, printing can be performed by controlling the ejection timing of ink, and an image can be appropriately formed.

  Next, another embodiment of the present invention will be described. This embodiment uses the same apparatus configuration as that of the third embodiment, but differs from the third embodiment in the processing algorithm for obtaining the relationship between the tension applied to the recording medium S and the amount of elongation. However, the algorithm in the third embodiment can be the same as that in the second embodiment shown in FIG. 6, and will be described based on this.

In FIG. 6, when the process is started in step S200, in the subsequent step S201, based on the detection data of the tension sensor 60, the tension of the recording medium S being conveyed becomes the first tension (T ₁ ). Control is performed by a tension roller control unit 170.

  In the next step S202, a test pattern is printed by the line head unit 150K. Here, as the test pattern to be used, two lines extending in the width direction of the recording medium S and having a predetermined interval can be used. As in the previous embodiment, the line head unit 150 for printing the test pattern may be other than the line head unit 150K.

In step S203, a test pattern is imaged (imaging the first image data) by the imaging unit 90 in a state where the tension of the recording medium S is maintained at the first tension (T ₁ ), and this is used as the main control unit 110. The distance g ₁ between the patterns is obtained by analyzing the image at.
FIG. 4A shows the image data captured in this step.

In the next step S204, based on the detection data of the tension sensor 60, the tension roller control unit 170 controls so that the tension of the recording medium S being conveyed becomes the second tension (T ₂ ).

  In the next step S205, a test pattern is printed by the line head unit 150K.

In step S206, the test pattern is imaged by the imaging unit 90 (second image data is imaged) while the tension of the recording medium S is maintained at the second tension (T ₂ ), and the inter-pattern distance g ₂ is set. get. FIG. 4B shows the image data captured in this step.

In step S207, a relational expression between the tension and the elongation amount of the recording medium is calculated from the distance g ₁ corresponding to the first tension (T ₁ ) and the distance g ₂ corresponding to the second tension (T ₂ ). Also in this embodiment, as shown in FIG. 5, it can be assumed that there is a linear proportional relationship between the tension of the recording medium S and the amount of elongation of the recording medium S.

  Also in the present embodiment, the relationship between the tension applied to the recording medium S and the amount of elongation can be obtained as shown in Expression (2). In step S208, the process ends.

  As described above, according to the image forming apparatus 10 according to the fourth embodiment, it is possible to calculate the relational expression between the tension applied to the recording medium S and the extension amount, and thus the relationship between the tension and the extension amount is unknown. Even for a certain new recording medium S, printing can be performed by controlling the ejection timing of ink, and an image can be appropriately formed.

  In the above embodiment, the example in which the UV ink is used as the ink ejected by the line head unit 150 has been described. However, in the present invention, a thermosetting ink or any other ink can be used. .

  In the above embodiments, the configuration using the line head as the configuration of the head for ejecting ink has been described. However, a serial head that ejects ink while scanning the width direction of the recording medium S is used. Also good. Furthermore, the present invention has been described by taking the inkjet image formation as an example. However, the present invention can also be applied to those that perform image formation by other methods.

DESCRIPTION OF SYMBOLS 1 ... Computer, 10 ... Printer, 19 ... Platen, 105 ... Interface, 110 ... Main control part, 111 ... CPU, 112 ... ROM, 113 ... RAM, 117: Drive voltage generation circuit, 120: Input operation unit, 130: Recording medium transport unit, 20: Supply roller, 30: Drive roller pair, 41: First transport roller, 42 ... 2nd conveyance roller, 43 ... 1st press roller, 44 ... 2nd press roller, 45 ... Press roller, 50 ... Drum roller, 60 ... Tension sensor, 70. ..Tension roller pair, 80 ... take-up roller, 90 ... imaging unit, 150 ... line head unit, 160 ... ultraviolet irradiation unit, 1 0 ... tension roller control unit, S ··· recording medium

Claims (8)

A transport unit for transporting a long recording medium;
An image forming unit that forms an image on the recording medium transported by the transport unit;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
The tension control unit controls the recording medium to apply a first tension, and the image forming unit forms a predetermined pattern,
In the state where the first tension is applied to the recording medium, the imaging unit captures first image data according to the predetermined pattern, and acquires a first distance from the first image data,
The conveyance of the recording medium by the conveyance unit is stopped, the second image data according to the predetermined pattern is imaged by the imaging unit in a state where a second tension different from the first tension is applied to the recording medium, Obtaining a second distance from the second image data;
An image forming apparatus, wherein a relational expression between a tension applied to the recording medium and an elongation amount is calculated from the first distance and the second distance. A transport unit for transporting a long recording medium;
An image forming unit that forms an image on the recording medium transported by the transport unit;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
The tension control unit controls the recording medium to apply a first tension, and the image forming unit forms a predetermined pattern,
In the state where the first tension is applied to the recording medium, the imaging unit captures first image data according to the predetermined pattern, and acquires a first distance from the first image data,
The tension control unit controls the recording medium to apply a second tension, and the image forming unit forms an image of a predetermined pattern.
With the second tension applied to the recording medium, the imaging unit captures the second image data according to the predetermined pattern, and obtains a first distance from the second image data,
An image forming apparatus, wherein a relational expression between a tension applied to the recording medium and an elongation amount is calculated from the first distance and the second distance. A transport unit including a rotatable drum roller for transporting a long recording medium;
An image forming unit that forms an image on the recording medium that is wound around the drum roller and conveyed;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
The tension control unit controls the recording medium to apply a first tension, and the image forming unit forms a predetermined pattern,
In the state where the first tension is applied to the recording medium, the imaging unit captures first image data according to the predetermined pattern, and acquires a first position from the first image data,
The conveyance of the recording medium by the conveyance unit is stopped, the second pattern different from the first tension is applied to the recording medium, and the imaging unit captures the predetermined pattern to obtain second image data. Obtaining a second position from the second image data;
An image forming apparatus, comprising: calculating a relational expression of tension and elongation applied to the recording medium from the first position and the second position. A transport unit including a rotatable drum roller for transporting a long recording medium;
An image forming unit that forms an image on the recording medium that is wound around the drum roller and conveyed;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
The tension control unit controls the recording medium to apply a first tension, and the image forming unit forms a predetermined pattern,
In the state where the first tension is applied to the recording medium, the imaging unit captures first image data according to the predetermined pattern, and acquires a first distance from the first image data,
The tension control unit controls the recording medium to apply a second tension, and the image forming unit forms an image of a predetermined pattern.
With the second tension applied to the recording medium, the imaging unit captures the second image data according to the predetermined pattern, and acquires a second distance from the second image data,
An image forming apparatus, wherein a relational expression between a tension applied to the recording medium and an elongation amount is calculated from the first distance and the second distance. A transport unit for transporting a long recording medium;
An image forming unit that forms an image on the recording medium transported by the transport unit;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
Controlling the first tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Imaging the first image data according to the predetermined pattern by the imaging unit in a state where the first tension is applied to the recording medium, and obtaining a first distance from the first image data;
The conveyance of the recording medium by the conveyance unit is stopped, the second image data according to the predetermined pattern is imaged by the imaging unit in a state where a second tension different from the first tension is applied to the recording medium, Obtaining a second distance from the second image data;
An image forming method, comprising: calculating a relational expression of tension and elongation applied to the recording medium from the first distance and the second distance. A transport unit for transporting a long recording medium;
An image forming unit that forms an image on the recording medium transported by the transport unit;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
Controlling the first tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Imaging the first image data according to the predetermined pattern by the imaging unit in a state where the first tension is applied to the recording medium, and obtaining a first distance from the first image data;
Controlling the second tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Imaging the second image data according to the predetermined pattern by the imaging unit in a state where the second tension is applied to the recording medium, and obtaining a first distance from the second image data;
An image forming method, comprising: calculating a relational expression of tension and elongation applied to the recording medium from the first distance and the second distance. A transport unit including a rotatable drum roller for transporting a long recording medium;
An image forming unit that forms an image on the recording medium that is wound around the drum roller and conveyed;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
Controlling the first tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Capturing the first image data according to the predetermined pattern by the imaging unit in a state where the first tension is applied to the recording medium, and acquiring a first position from the first image data;
The conveyance of the recording medium by the conveyance unit is stopped, the second pattern different from the first tension is applied to the recording medium, and the imaging unit captures the predetermined pattern to obtain second image data. Obtaining a second position from the second image data;
An image forming method comprising: calculating a relational expression of tension and elongation applied to the recording medium from the first position and the second position. A transport unit including a rotatable drum roller for transporting a long recording medium;
An image forming unit that forms an image on the recording medium that is wound around the drum roller and conveyed;
A tension control unit that controls a tension applied to the recording medium during conveyance of the recording medium by the conveyance unit;
An imaging unit that captures an image formed on the recording medium by the image forming unit;
A main control unit that controls the transport unit, the image forming unit, the tension control unit, and the imaging unit and performs arithmetic processing;
The main control unit
Controlling the first tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Imaging the first image data according to the predetermined pattern by the imaging unit in a state where the first tension is applied to the recording medium, and obtaining a first distance from the first image data;
Controlling the second tension to be applied to the recording medium by the tension control unit, and forming an image of a predetermined pattern by the image forming unit;
Capturing the second image data according to the predetermined pattern by the imaging unit in a state where the second tension is applied to the recording medium, and obtaining a second distance from the second image data;
An image forming method, comprising: calculating a relational expression of tension and elongation applied to the recording medium from the first distance and the second distance.

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