EP3056348A1

EP3056348A1 - Digital type duplex printing method and printing material

Info

Publication number: EP3056348A1
Application number: EP16155389.6A
Authority: EP
Inventors: Masaru Ohnishi
Original assignee: Mimaki Engineering Co Ltd
Current assignee: Mimaki Engineering Co Ltd
Priority date: 2015-02-13
Filing date: 2016-02-12
Publication date: 2016-08-17
Anticipated expiration: 2036-02-12
Also published as: EP3056348B1; JP2016147239A; JP6437334B2

Abstract

The disclosure is to provide a digital type duplex printing method of printing images on both sides of a printing material such that a front-side image and a back-side image overlap each other. The digital type duplex printing method performs duplex printing with a digital type printer 10 which includes a print head 11 for performing printing by moving with respect to a printing material 50 and allows a printing jig 20 for setting the printing material 50 to be installed at a predetermined position such that the printing jig can be reversed. The printing material 50 is fixed in a stretched state to the printing jig 20, which is installed at the predetermined position. On the front surface of the printing material 50, a front-side image 31 and a front-side position detection mark 32 are printed. The printing jig 20 is inverted and is installed at the predetermined position. On the back surface of the printing material 50, a back-side position detection mark 42 is printed. The back-side position detection mark 42 and the front-side position detection mark 32 are compared from any one of the front surface and the back surface, and the relative position of the back-side image to the front-side image of the printing material 50 is corrected on the basis of the comparison. A back-side image 41 is printed at the corrected relative position on the back surface of the printing material 50.

Description

Technical Field

The disclosure relates to a digital type duplex printing method of performing duplex printing such that a front-side image and a back-side image of a printing material overlap each other, and a printing material.

Background Art

In general, a digital type printing apparatus jets ink from an inkjet print head or the like, thereby performing printing on printing materials. In that case, print data on various printing material designs is stored in a memory of a control unit in advance, whereby it is possible to accurately print the same designs.
As digital type printing apparatuses using the characteristics of digital printing, there are technologies like a technology capable of texture printing according to the types of fabrics which are printing materials, for example, as shown in Patent Literature 1.

Citation List

Patent Literature

[Patent Literature 1] JP-A-2001-322263

Summary of Invention

Technical Problem

Printing materials such as scarves and handkerchiefs are products which are produced in various kinds in small quantities by performing printing in various designs. Some of scarves and handkerchiefs are thin silk fabric products. Silk is a luxury item. In printing designs on silk, silk-screen printing is used. In the silk-screen printing, if printing is performed with a comparatively large amount of ink, since the ink seeps from the back surface of fabric, it is possible to see a design from both surfaces. However, in the silk-screen printing, for each design, a silk screen is made and printing is performed. Therefore, the cost is high. The silk-screen printing is not suitable for producing a variety of products in small quantities.
Meanwhile, it is difficult to print scarves, handkerchiefs, and the like with a digital type printing apparatus. The reason is as follows. That is, since an ejection amount of ink which is used in inkjet printing is small, the ink does not penetrate to a back surface. Even if it is possible to secure an ejection amount such that ink can penetrate to a back surface, since the viscosity of ink is low, ink is blurred, resulting in a reduction in image quality.
In a case of performing duplex printing, even with a very small amount of ink, duplex printing is possible. However, many scarves and handkerchiefs are so diaphanous that it is possible to see front and back designs through them, and if front and back images do not completely coincide with each other, the quality is degraded, resulting in a decrease in the value. However, in a case of inkjet printing, it is difficult to completely match the positions of front and back print images with each other.
An object of the disclosure is to provide a digital type duplex printing method for accurately printing a print design (image) from the front and a print design (image) from the back, at desired positions, in a case of performing duplex printing on a printing material, and a printing material.

Solution to Problem

(FIRST INVENTION)

A first invention relates to a digital type duplex printing method of performing duplex printing with a digital type printer which includes a print head for performing printing by moving with respect to a printing material and allows a printing jig for setting the printing material to be installed at a predetermined position and allows the printing jig to be reversed and be installed at the predetermined position.
That is, the first invention is a digital type duplex printing method which includes: a jig setting process of fixing a printing material in a stretched state to the printing jig and installing the printing jig at the predetermined position; a front-side image printing process of printing a front-side image and a front-side position detection mark on the front surface of the printing material; a jig inverting/setting process of inverting the printing jig and installing the printing jig at the predetermined position; a back-side position detection mark printing process of printing a back-side position detection mark on the back surface of the printing material; a comparing process of comparing the back-side position detection mark and the front-side position detection mark from any one of the front surface and the back surface; a correcting process of correcting the relative position of a back-side image to the front-side image of the printing material on the basis of the comparing process; and a back-side image printing process of printing the back-side image on the back surface of the printing material at the relative position corrected in the correcting process.

(EXPLANATION OF TERMS)

Printing materials include not only fabrics but also films. Here, the term "fabric" is the collective name of textile products such as fabrics and woven fabrics using silk, cotton, hemp, or a mixture thereof, as yarn.
As a front-side position detection mark and a back-side position detection mark, scale marks are used in a present embodiment to be described below. However, for example, an insect-shaped mark (such as a dragonfly-shaped mark), a mark having a simple shape (such as ◊ or Δ), a plurality of dots arranged regularly, or the like may be used.
Also, it is general to print the front-side position detection mark and the back-side position detection mark on a portion to be cut out and discarded such that they are not shown in a final product. However, it is not prevented to use images like use of the front-side position detection mark and the back-side position detection mark as product designs.
The comparing process includes not only automatic detection using an engineering sensor but also a case using the result of visual determination of a worker.
Correction on the relative position in the correcting process includes all of a case of moving the print head with respect to the printing material, a case of moving the printing jig having the printing material with respect to the print head, and a case of moving both of the print head and the printing jig.
The back-side image may be the same as the front-side image, or may be an image different from the front-side image as long as the images printed on the front and back surfaces are combined to form an image having one visibly recognizable meaning.

(EFFECTS)

Since the printing material extends or contracts according to environment such as temperature and humidity, the printing material is fixed in a stretched state to the printing jig, whereby an assumption that printing accuracy of the positions, sizes, and the like of print images is kept high is secured.
Although the digital type printer allows the printing jig to be installed at the predetermined position and allows the printing jig to be reversed and be installed at the predetermined position, due to influence of component accuracy or the like, a slight positional deviation between the front-side image and the back-side image of fabric may occur. In this invention, when the front-side image is printed, the front-side image and the front-side position detection mark are printed. Meanwhile, after the jig is inverted and fixed, the back-side position detection mark is printed before the back-side image is printed. Therefore, it is possible to eliminate the influence of component accuracy, the influence of assembly errors, and the like, and thus it is possible to match the front-side image and the back-side image with each other with high accuracy.
The front-side position detection mark and the back-side position detection mark are compared from any one of the front surface and the back surface. On the basis of that comparison, the relative position of the back-side image to the front-side image of the printing material is corrected. Thereafter, the back-side image is printed on the back surface of the printing material. Therefore, it is possible to position the back-side image and the front-side image with high accuracy, and it is possible to perform printing on both surfaces of the printing material.
For example, it becomes possible to print very colorful and luxurious images on both surfaces of a scarf, a handkerchief, or the like. Also, since it also becomes possible to print very colorful images on both surfaces of thick luxury fabric or woven fabric such as a curtain, the first invention contributes to implementation of luxury products.

(FIRST VARIATION OF FIRST INVENTION)

The first invention can provide a variation as follows.
That is, in the jig setting process, while the printing material is pinched between an upper frame and a lower frame constituting the printing jig, and is protruded outward from the upper frame and the lower frame after the whole of the printing material is wet, a tensile load is applied to the circumference of the printing material to fix the upper frame and the lower frame with fixtures.

(EFFECTS)

If the printing material is wet with water, the fiber extends. In the state where the tensile load has been applied to the circumference of the extended printing material, the upper frame and the lower frame are fixed, whereby the printing material becomes a stretched state on the printing jig. Therefore, it is difficult for the printing material to extend any more if printing is performed with liquid ink, and thus stable print images are obtained. Since this process is used, the first variation contributes to improvement of the accuracy of the correction state of the relative positions of the front-side image and the back-side image of the printing material.

(SECOND VARIATION OF FIRST INVENTION)

The first invention can also provide a variation as follows.
That is, the front-side position detection mark of the front-side image printing process is a plurality of scale marks which are printed with a pitch P on both sides from a front-side zero point for a position correction on a straight line.
Also, the back-side position detection mark of the back-side position detection mark printing process is a plurality of scale marks which are printed with a pitch (P + ΔP) on both sides from a back-side zero point for the position correction on the same straight line as that of the front-side image printing process.
Further, in the comparing process, in a case where the number of scale marks from the position of a scale mark of the back-side position detection mark coinciding with a scale mark of the front-side position detection mark to the back-side zero point for the position correction is α, the positional deviation amount of the back-side position detection mark relative to the front-side position detection mark is measured as ΔP × α.

(EXPLANATION OF TERM)

"ΔP" means a minute dimension with respect to the pitch P, for example, a dimension which is 0.1 or 0.05 of the pitch P.

(EFFECTS)

In a case of printing scale marks with the pitch P, as the front-side position detection mark, on both sides from a front-side zero point, on an X axis in a two-dimensional direction of an X axis and a Y axis on the plane of the printing material, the scale marks on one side from the front-side zero point are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n. Meanwhile, in a case of printing scale marks with the pitch (P + ΔP), as the back-side position detection mark, on both sides from the back-side zero point on the X axis, the scale marks on one side from the back-side zero point are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n.
For example, in a case where the front-side position detection mark and the back-side position detection mark coincide with each other at the scale mark of -3, there is a positional deviation amount of ΔP × (-3). In other words, the back-side zero point has a deviation of (3 × ΔP) in the positive direction on the X axis with respect to the front-side zero point. Therefore, the position of a print head 11 is corrected in the negative direction on the X axis by (3 × ΔP), such that the front-side zero point and the back-side zero point coincide with each other. Even on the Y axis, the position correction is performed similarly.
As the result of the position correction described above, for example, the back-side image and the front-side image which are reverse images are positioned with high accuracy, thereby becoming capable of being printed on both surfaces of the printing material.
Also, as the front-side position detection mark and the back-side position detection mark, scale marks with a pitch P and scale marks with a pitch (P + ΔP) can be printed on both sides from a back-side zero point on a straight line inclined, for example, at 45° with respect to the X axis and the Y axis, not on the X axis and the Y axis.
In this case, the positional deviation amount in the direction inclined at 45° is converted into a positional deviation amount in the X axis direction and a positional deviation amount in the Y axis direction, and then position correction is performed as described above. Alternatively, the position is corrected in the direction inclined at 45°.

(THIRD VARIATION OF FIRST INVENTION)

In the second variation of the first invention described above, it is more preferable to dispose the front-side position detection mark and the back-side position detection mark close to each other such that it is possible to visibly compare them.
For example, an apple design is cut into left and right halves such that the cut edges have a zigzag shape, and the left half apple design is used as the front-side position detection mark, and the right half apple design is used as the back-side position detection mark, and they are disposed so as to be close to each other. In this case, if any deviation does not occur in the X axis direction and the Y axis direction, the zigzag cut edges match, resulting in one apple. If the front-side position detection mark and the back-side position detection mark do not match, position correction may be performed such that the zigzag cut edges match.

(FOURTH VARIATION OF FIRST INVENTION)

The first invention can provide a variation as follows.
That is, the front-side position detection mark and the back-side position detection mark are marks from which both of two-dimensional deviations relative to the X axis and the Y axis on the plane of the printing material can be detected.

(EFFECTS)

Since both of two-dimensional deviations relative to the X axis and the Y axis on the plane of the printing material can be detected at the same time from the front-side position detection mark and the back-side position detection mark, it is possible to perform correction even in view of the extension/contraction state of the printing material in the X axis direction and the Y axis direction.

(SECOND INVENTION)

A second invention relates to a printing material which is used in a case of performing duplex printing with a digital type printer, which includes a print head for performing printing by moving with respect to the printing material and allows a printing jig for setting the printing material to be installed at a predetermined position and allows the printing jig to be reversed and be installed at the predetermined position.
On the front surface of the printing material, a front-side image and a front-side position detection mark are printed, and after the printing jig is inverted and installed at the predetermined position, on the back surface of the printing material, a back-side position detection mark is printed at a position corresponding to the front-side position detection mark.

(VARIATION OF SECOND INVENTION)

It is more preferable that the second invention should be implemented as follows.
That is, as the front-side position detection mark, scale marks are printed with a pitch P on both sides from a front-side zero point on a straight line, and as the back-side position detection mark, scale marks are printed with a pitch (P + ΔP) on both sides from a back-side zero point on the same straight line as that of the front-side position detection mark.
According to the first invention, it is possible to provide a digital type duplex printing method for accurately printing a print design from the front and a print design from the back, at desired positions, in a case of performing duplex printing on a printing material.
According to the second invention, it is possible to provide a printing material making it possible to accurately print a print design from the front and a print design from the back, at desired positions, in a case of performing duplex printing on the printing material by printing a front-side image and a front-side position detection mark on the front surface of the printing material and printing a back-side position detection mark at a position of the back surface of the printing material corresponding to the front-side position detection mark.

Brief Description of Drawings

FIG. 1(a) is a perspective view schematically illustrating a digital type printer of a present embodiment of the disclosure, and FIG. 1(b) is a partial detail view of a printing jig.
FIGs. 2(a) to 2(c) are schematic explanatory views illustrating processes of a digital type duplex printing method of the present embodiment of the disclosure.
FIGs. 3(a) and 3(b) are schematic explanatory views illustrating processes following FIG. 2.
FIGs. 4(a) and 4(b) are schematic explanatory views illustrating an example of measurement of a positional deviation amount in an X axis direction, and FIG. 4(c) is a schematic explanatory view illustrating an example of measurement of a positional deviation amount in a Y axis direction.

Description of Embodiments

Hereinafter, a present embodiment of the disclosure will be described with reference to the drawings. Here, FIGs. 1 to 4 are used.
A digital type duplex printing method according to the present embodiment is a method of performing duplex printing with a digital type printer 10 as shown in FIG. 1(a).
The digital type printer 10 includes a print head 11 which performs printing on each printing material 50 while moving. Each printing material 50 is set on a printing jig 20, and the printing jig 20 is installed at a predetermined position below the print head 11. The print head 11 is installed so as to be movable in an X axis direction along an X axis travel support member 12.
Print data on various designs for printing materials 50 are stored in advance in a memory of a control unit of the digital type printer 10, whereby it is possible to accurately print the same designs.
Also, two Y axis travel support members 13 are disposed outside the predetermined position for setting the printing jig 20, so as to face each other. The X axis travel support member 12 is installed so as to be movable in a Y axis direction along both Y axis travel support members 13. Therefore, the print head 11 is relatively movable in a two-dimensional direction of the X axis and the Y axis above the printing jig 20.
Also, the above described printing jig 20 can be installed at the predetermined position, and can also be reversed and be installed at the predetermined position. In the present embodiment, the printing jig 20 is composed of an upper frame 21 and a lower frame 22 which form a frame material form having a rectangular shape. In other words, the outer circumferential portion of fabric which is the printing material 50 is pinched from the front surface and the back surface by the upper frame 21 and the lower frame 22.
At four corners of each of the upper frame 21 and the lower frame 22, as shown in FIG. 1(b), there are through-holes 24a for positioning to position and fix them such that they overlap each other.
Between the through-holes 24a for positioning formed at the four corners, there is a plurality of through-holes 24b for fixing formed at appropriate intervals. Retaining screws 23a for positioning are inserted as fixtures 23 into the through-holes 24a for positioning formed at the four corners, and are tightened. A plurality of retaining screws 23b for fixing is inserted as other fixtures 23 into the plurality of through-holes 24b for fixing, and is tightened.
The printing jig 20 includes a printing-jig mounting base 14 for mounting the frame part (the upper frame 21 and the lower frame 22). Also, the printing-jig mounting base 14 has contact reference surfaces 15 for bringing the side edges of two neighboring sides, perpendicular to each other, of the frame part of the printing jig 20 into contact with them. Therefore, it is possible to install the printing jig 20 at the predetermined position by bringing the side edges of the frame part of the printing jig 20 into contact with the contact reference surfaces 15.
Also, after inverting the printing jig 20, it is possible to install the printing jig 20 at the predetermined position by bringing the side edges of the frame part of the printing jig 20 into contact with the contact reference surfaces 15.
As another method for installing the printing jig 20 at the predetermined position of the printing-jig mounting base 14, it is possible to protrude positioning pins on both ends of each retaining screw 23a for positioning. Meanwhile, it is possible to form reference holes for positioning in the printing-jig mounting base 14 such that the positioning pins of the retaining screws 23a for positioning fixing the upper frame 21 and the lower frame 22 at the four corners can be inserted into the reference holes.
Therefore, the positioning pins of the retaining screws 23a for positioning provided at the four corners of the printing jig 20 can be inserted into the reference holes for positioning formed in the printing-jig mounting base 14, whereby it is possible to install the printing jig 20 at the predetermined position, and it is also possible to install the printing jig 20 at the predetermined position even if the printing jig is inverted.
Now, a method of performing duplex printing with the above described digital type printer 10 will be described.
The digital type duplex printing method of the present embodiment includes a jig setting process, a front-side image printing process, a jig inverting/setting process, a back-side position detection mark printing process, a comparing process, a correcting process, and a back-side image printing process.
The jig setting process fixes fabric 51, as the printing material 50, in a stretched state to the printing jig 20. Thereafter, the printing jig is installed at the predetermined position of the printing-jig mounting base 14. Also, the printing materials 50 include not only the fabric 51 but also films. Here, the fabric 51 is the collective name of textile products such as fabrics and woven fabrics using silk, cotton, hemp, or a mixture thereof, as yarn.
As shown in FIG. 2(a), the outer circumferential portion of the fabric 51 is pinched between the upper frame 21 and the lower frame 22 of the printing jig 20, from the front surface and the back surface. In a state where a tensile load has been applied to the circumference of the fabric 51 protruded outward from the upper frame 21 and the lower frame 22 while moistening the whole of the fabric 51, the upper frame 21 and the lower frame 22 are fixed as shown in FIG. 1(a) and FIG. 2(b) by the retaining screws 23a for positioning and the retaining screws 23b for fixing which are the fixtures 23.
In the present embodiment, a plurality of weights 25 is hooked to the circumference of the fabric 51 so as to hang down as shown in FIG. 2(a), whereby a tensile load is applied. If the fabric 51 is wet with water, the fiber extends. In the state where the tensile load has been applied to the circumference of the extended fabric 51, the upper frame 21 and the lower frame 22 are fixed, whereby the fabric 51 becomes a stretched state on the printing jig 20. When printing is performed in the next process, since the fabric 51 does not extend any more even if printing is performed with liquid ink, stable print images are obtained. In other words, a tensile load contributes to improvement of the accuracy of the correction state of the relative positions of a front-side image 31 on the front surface of the fabric 51 and a back-side image 41 which is a reverse image on the back surface, as will be described below in detail.
The method of applying a tensile load to the fabric 51 is not limited to the above described weights 25. It is possible to use springs for stretching, or any other method can be used. The timing of wetting the fabric 51 with water may be before the fabric is pinched between the upper frame 21 and the lower frame 22, and at that timing, the fabric 51 subjected to no preprocess is wet by spraying a pretreatment agent such as water.
The printing jig 20 fixing the fabric 51 in the stretched state as described above can be installed at the predetermined position by bringing the side edges of the frame part of the printing jig 20 into contact with the contact reference surfaces 15 of the printing-jig mounting base 14 as shown in FIG. 1(a).
The front-side image printing process prints the front-side image 31 and a front-side position detection mark 32 on the front surface of the fabric 51 by jetting ink from the print head 11 while moving the print head 11 in the two-dimensional direction of the X axis and the Y axis. At this time, since the fabric 51 wet with water and stretched on the printing jig 20 does not extend, that is, does not loosen even if printing is performed with liquid ink, high-accuracy print images with stable position accuracy are obtained. Also, the front-side position detection mark 32 is printed at a position apart from the front-side image 31, that is, at a position which will not become a product.
It is assumed that, as the front-side position detection mark 32, scale marks are printed with a pitch P on both sides from a front-side zero point on a straight line. As an example thereof, an X axis front-side position detection mark 32x is printed as shown in FIGs. 4 (a) and 4 (b) . Further, a Y axis front-side position detection mark 32y is printed as shown in FIG. 4(c).
Although a back-side position detection mark 42 is shown in FIGs. 4(a) to 4(c), in this process, the back-side position detection mark 42 is not printed. Also, the color of the front-side position detection mark 32 is black in the present embodiment, but is not especially limited as long as it is a conspicuous color.
The jig inverting/setting process inverts the printing jig 20 with the fabric 51 having the front surface subjected to printing in the above described front-side image printing process, and installs the printing jig at the predetermined position of the printing-j ig mounting base 14 as shown in FIG. 3(a). In other words, the side edges of the frame part of the printing jig 20 are brought into contact with the contact reference surfaces 15 of the printing-jig mounting base 14, whereby the printing jig 20 is installed at the predetermined position. At this time, the printing jig is installed at the predetermined position such that the back surface of the fabric 51 of the printing jig 20 is mirror-symmetrical to the front-side image 31.
The back-side position detection mark printing process prints the back-side position detection mark 42 at a position of the back surface of the fabric 51 of the inverted printing jig 20 corresponding to the front-side position detection mark 32 by jetting ink from the print head 11 while moving the print head 11 in the two-dimensional direction of the X axis and the Y axis as shown in FIG. 3(a).
It is assumed that, as the back-side position detection mark 42, scale marks are printed with a pitch (P + ΔP) on both sides from a back-side zero point on the same straight line as that of the front-side image printing process. As an example thereof, an X axis back-side position detection mark 42x is printed so as to be adjacent and shifted to the X axis front-side position detection mark 32x with a predetermined pitch in the Y axis direction as shown in FIGs. 4(a) and 4(b). Here, ΔP means a minute dimension with respect to the pitch P, for example, a dimension which is 0.1 or 0.05 of the pitch P.
As shown in FIG. 4(c), a Y axis back-side position detection mark 42y is printed so as to be adjacent and shifted to the Y axis front-side position detection mark 32y with a predetermined pitch in the X axis direction. In the present embodiment, as the color of the back-side position detection mark 42, red is used. Although a conspicuous color is preferable, the color of the back-side position detection mark is not especially limited. However, in order to distinguish the back-side position detection mark from the above described front-side position detection mark 32, it is desired that the color of the back-side position detection mark is different from that of the front-side position detection mark 32.
The comparing process compares the back-side position detection mark 42 and the front-side position detection mark 32 from any one of the front surface and the back surface. At this time, for example, the positional deviation amount in the X axis direction and the positional deviation amount in the Y axis direction between the back-side position detection mark 42 and the front-side position detection mark 32 are measured. For example, in a case where the number of scale marks from the position of a scale mark of the back-side position detection mark 42 coinciding with a scale mark of the front-side position detection mark 32 to the back-side zero point is α, the positional deviation amount of the back-side position detection mark 42 relative to the front-side position detection mark 32 is measured as ΔP × α.
In a case of printing scale marks with the pitch P, as the X axis front-side position detection mark 32x, on both sides from the front-side zero point Ax, for example, on the X axis, as shown in FIGs. 4(a) and 4(b), the scale marks on one side from the front-side zero point Ax are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n. Meanwhile, in a case of printing scale marks with the pitch (P + ΔP), as the X axis back-side position detection mark 42x, on both sides from the back-side zero point Bx on the X axis, the scale marks on one side from the back-side zero point Bx are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n.
In a case where the X axis front-side position detection mark 32x and the X axis back-side position detection mark 42x coincide with each other at the scale mark of 0 (the front-side zeropoint Ax and back-side zero point Bx) like in the case of FIG. 4(a), since α becomes 0 (zero), the positional deviation amount (ΔP × α) on the X axis becomes 0 (zero) (= ΔP × 0).
As another example, in a case where the X axis front-side position detection mark 32x and the X axis back-side position detection mark 42x coincide with each other at the scale mark of -5 like in the case of FIG. 4(b), since α, becomes -5 (α = -5), the positional deviation amount (ΔP × α) on the X axis becomes ΔP × (-5).
Even on the Y axis, similarly on the X axis, a positional deviation amount is measured. As an example thereof, in a case of printing scale marks with the pitch P, as the Y axis front-side position detection mark 32y, on both sides from the front-side zero point Ay, for example, on the Y axis, as shown in FIG. 4(c), the scale marks on one side from the front-side zero point Ay are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n.
Meanwhile, in a case of printing scale marks with the pitch (P + ΔP), as the Y axis back-side position detection mark 42y, on both sides from the back-side zero point By on the Y axis, the scale marks on one side from the back-side zero point By are represented by +1, +2, +3, ..., and +n, and the scale marks on the other side are represented by -1, -2, -3, ..., and -n.
In a case where the Y axis front-side position detection mark 32y and the Y axis back-side position detection mark 42y coincide with each other at the scale mark of 0 (the front-side zero point Ay and the back-side zero point By) like in the case of FIG. 4(c), since α becomes 0 (zero), the positional deviation amount (ΔP × α) on the Y axis becomes 0 (zero) (= ΔP × 0). Meanwhile, in a case where the Y axis front-side position detection mark 32y and the Y axis back-side position detection mark 42y coincide with each other at the scale mark of +3, since α becomes +3 (α = +3), the positional deviation amount (ΔP × α) on the Y axis becomes ΔP × (3).
Also, the comparing process includes not only automatic detection using an engineering sensor but also a case using the result of visual determination of a worker. In the case of automatic detection using a sensor, for example, the back-side position detection mark 42 and the front-side position detection mark 32 are imaged from any one of the front surface and the back surface by an imaging means such as a CCD camera. From the acquired images, the positional deviation amount in the X axis direction and the positional deviation amount in the Y axis direction are measured by an image processing apparatus.
Meanwhile, in visual observation of a worker, the worker measures the positional deviation amount in the X axis direction and the positional deviation amount in the Y axis direction between the back-side position detection mark 42 and the front-side position detection mark 32 as described above, from any one of the front surface and the back surface.
The correcting process corrects the relative positions of the front-side image and the back-side image of the printing material 50 on the basis of the above described comparing process. For example, on the basis of the positional deviation amount in the X axis direction and the positional deviation amount in the Y axis direction, the relative position of the print head 11 is corrected. Also, correction on the relative position in the correcting process includes all of a case of performing correction by moving the position of the print head 11 with respect to the fabric 51, a case of performing correction by moving the printing jig 20 having the fabric 51 with respect to the print head 11, and a case of performing correction by moving both of the print head and the printing jig.
Also, the position of at least one image of front/back image data can be corrected by a raster image processor (RIP). Data on the positional deviation amount in the X axis direction and the positional deviation amount in the Y axis direction measured in the comparing process is rasterized into dot information to be corrected which is transmitted to the control unit. The control unit transmits a command to correct the position of the print head 11.
Also, in the above described correction, a worker can manually input correction data to the control unit, and performs a correction operation. Alternatively, it is possible to automatically perform correction (reset). For example, correction data measured by automatic detection using an engineering sensor on the basis of the comparing process is transmitted to the control unit. The control unit transmits a command to correct (reset) the position of the print head 11.
In the case of FIG. 4 (a) described above, since the positional deviation amount (ΔP × α) on the X axis becomes 0 (zero) (= ΔP × 0), the position of the print head 11 on the X axis does not need to be corrected.
In the case of FIG. 4(b) described above, the positional deviation amount (ΔP × α) on the X axis becomes ΔP × (-5). Therefore, the back-side zero point has a deviation of (5 × ΔP) in the positive direction on the X axis with respect to the front-side zero point. The position of the print head 11 is corrected in the negative direction on the X axis by (5 × ΔP), such that the front-side zero point and the back-side zero point coincide with each other.
In the case of FIG. 4(c) described above, since the positional deviation amount (ΔP × α) on the Y axis becomes 0 (zero) (= ΔP × 0), the position of the print head 11 on the Y axis does not need to be corrected.
As described above with respect to the comparing process, in a case where the positional deviation amount (ΔP × α) on the Y axis is ΔP × (3), the back-side zero point has a deviation of (3 × ΔP) in the negative direction on the Y axis with respect to the front-side zero point. The position of the print head 11 is corrected in the positive direction on the Y axis by (3 × ΔP), such that the front-side zero point and the back-side zero point coincide with each other.
The back-side image printing process moves the print head 11 to the relative position corrected in the above described correcting process, in the two-dimensional direction of the X axis and the Y axis. Ink is jetted from the print head 11 onto the back surface of the fabric 51, whereby the back-side image 41 which is a reverse image to overlap the front-side image 31 is printed. Here, the back-side image 41 which is a reverse image to overlap the front-side image 31 means an image to overlap the front-side image not only in the image print position but also in the image size.
Also, the back-side image 41 may be a reverse image to overlap the front-side image 31 or may be an image different from the front-side image 31. In other words, the back-side image does not necessarily need to overlap the front-side image, and can be set such that the front-side image 31 and the back-side image 41 form a harmonic design as seen through the fabric.
In printing according to the processes as described above, the back-side image 41 and the front-side image 31 are positioned with high accuracy, whereby it is possible to print very colorful images on both surfaces of the fabric 51. For example, even if the fabric 51 is a scarf, a handkerchief, or the like made of silk, according to the digital type duplex printing method of the present embodiment, it is possible to print very colorful images on both surfaces of the fabric 51 such that the images are positioned on the front side and the back side with respect to each other with high accuracy.
In a case where silk products are expensive products, it is required to perform printing in small quantities in various designs. In other words, various products are produced in small quantities. However, if the digital type duplex printing method according to the present embodiment is used, it is possible to perform printing accurately and efficiently, whereby it becomes possible to produce luxury products at low cost, resulting in a reduction in production cost and an increase in profit margins.
In a case of a thick product like carpet or curtain fabric, a front-side print image is not shown on the back side. However, even in a case of a thick printing material, if the digital type duplex printing method of the present embodiment is used, it is possible to print very colorful images on both surfaces such that the images are positioned on the front side and the back side with respect to each other with high accuracy. Since efficient production becomes possible, even in a case of luxury products, the digital type duplex printing method of the present embodiment contributes to a reduction in production cost. After printing on the printing material 50 finishes, the printed colors are fixed, and a washing process is performed, whereby a product is completed.
As the front-side position detection mark 32 and the back-side position detection mark 42, scale marks with a pitch P or scale marks with a pitch (P + ΔP) can be printed on both sides from a front-side zero point and back-side zero point on a straight line inclined, for example, at 45° with respect to the X axis and the Y axis, not on the X axis and the Y axis.
In this case, the positional deviation amount in the direction inclined at 45° is converted into a positional deviation amount on the X axis and a positional deviation amount on the Y axis, and then position correction is performed as described above. Alternatively, the position is corrected in the direction inclined at 45°. The positional-deviation-amount measuring method depends on specifications required for final products, restrictions in production fields, and so on, and visual observation of a maker, measuring means such as a scale measuring instrument and a CCD camera, and the like can be used.
Also, in the above described present embodiment, as the front-side position detection mark and the back-side position detection mark, scale marks are used. However, for example, a insect-shaped mark (such as a dragonfly-shaped mark), a mark having a simple shape (such as ◊, Δ, or ●), or the like can be used.
The printing materials 50 according to the present embodiment of the disclosure will be described.
The printing materials 50 of the present embodiment are produced by the digital type duplex printing method described above with the digital type printer 10 described above. In other words, on the front surface of each printing material 50, the front-side image 31 and the front-side position detection mark 32 are printed.
Also, after the printing jig 20 is inverted and is installed at the predetermined position, on the back surface of the corresponding printing material 50, the back-side position detection mark 42 is printed at a position according to the front-side position detection mark 32.
On each printing material 50, as the front-side position detection mark 32, scale marks with the pitch P are printed on both sides from a front-side zero point on a straight line. Meanwhile, as the back-side position detection mark 42, scale marks with the pitch (P + ΔP) are printed on both sides from a back-side zero point on the same straight line as that of the front-side position detection mark 32.
As described above, each printing material 50 of the present embodiment is obtained by printing the front-side image 31 and the front-side position detection mark 32 on the front surface of the fabric 51 and printing the back-side position detection mark 42 at a position of the back side of the fabric 51 corresponding to the front-side position detection mark 32. Therefore, in a case of performing duplex printing on the fabric 51, it is possible to print the front-side image 31 which is a print design from the front, and the back-side image 41 which is a print design from the back, at desired positions.

Industrial Applicability

The disclosure can be used in a wide range such as the printing industry, the textile dyeing industry, selling and producing related to fibers and clothes, selling and producing related to thick fabric products such as carpet, and selling and producing of printing materials related to printing.

Reference Signs List

10: digital type printer
11: print head
12: X axis travel support member
13: Y axis travel support member
14: printing-jig mounting base
15: contact reference surface
20: printing jig
21: upper frame
22: lower frame
23: fixture
23a: retaining screw for positioning
23b: retaining screw for fixing
24a: through-hole for positioning
24b: through-hole for fixing
25: weight
31: front-side image
32: front-side position detection mark
32x: X axis front-side position detection mark
32y: Y axis front-side position detection mark
41: back-side image
42: back-side position detection mark
42x: X axis back-side position detection mark
42y: Y axis back-side position detection mark
50: printing material
51: fabric

Claims

A digital type duplex printing method of performing duplex printing with a digital type printer which includes a print head for performing printing by moving with respect to a printing material and allows a printing jig for setting the printing material to be installed at a predetermined position, comprising:
a jig setting process of setting the printing material in a stretched state on the printing jig;

a front-side image printing process of printing a front-side image and a front-side position detection mark on the front surface of the printing material;

a jig inverting/setting process of reversing the printing jig and installing the printing jig at the predetermined position;

a back-side position detection mark printing process of printing a back-side position detection mark on the back surface of the printing material;

a comparing process of comparing the back-side position detection mark and the front-side position detection mark from any one of the front surface and the back surface;

a correcting process of correcting the relative position of a back-side image to the front-side image of the printing material on the basis of the comparing process; and

a back-side image printing process of printing the back-side image on the back surface of the printing material at the relative position corrected in the correcting process.
The digital type duplex printing method according to claim 1, wherein:
in the jig setting process, while the printing material is pinched between an upper frame and a lower frame constituting the printing jig, and is protruded outward from the upper frame and the lower frame after the whole of the printing material is wet, a tensile load is applied to the circumference of the printing material to fix the upper frame and the lower frame with fixtures.
The digital type duplex printing method according to claim 1 or 2, wherein:
the front-side position detection mark of the front-side image printing process is a plurality of scale marks which are printed with a pitch P on both sides from a front-side zero point for a position correction on a straight line,

the back-side position detection mark of the back-side position detection mark printing process is a plurality of scale marks which are printed with a pitch (P + ΔP) on both sides from a front-side zero point for the position correction on the same straight line as that of the front-side image printing process, and

in the comparing process, in a case where the number of scale marks from the position of a scale mark of the back-side position detection mark coinciding with a scale mark of the front-side position detection mark to the back-side zero point is α, the positional deviation amount of the back-side position detection mark relative to the front-side position detection mark is measured as ΔP × α.
The digital type duplex printing method according to claim 3, wherein:
the front-side position detection mark and the back-side position detection mark are disposed close to each other such that it is possible to visibly compare them.
The digital type duplex printing method according to any one of claims 1 to 4, wherein:
between the front-side position detection mark and the back-side position detection mark, it is possible to detect both of deviations in a two-dimensional direction relative to an X axis and a Y axis on the plane of the printing material.
A printing material which is used in a case of performing duplex printing with a digital type printer, which includes a print head for performing printing by moving with respect to the printing material and allows a printing jig for setting the printing material to be installed at a predetermined position and allows the printing jig to be reversed and be installed at the predetermined position, wherein:
on the front surface of the printing material, a front-side image and a front-side position detection mark are printed, and

after the printing jig is inverted and installed at the predetermined position, on the back surface of the printing material, a back-side position detection mark is printed at a position corresponding to the front-side position detection mark.
The printing material according to claim 6, wherein:
as the front-side position detection mark, scale marks are printed with a pitch P on both sides from a front-side zero point on a straight line, and as the back-side position detection mark, scale marks are printed with a pitch (P + ΔP) on both sides from a back-side zero point on the same straight line as that of the front-side position detection mark.