JP4239587B2 - Inkjet printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet printer, and more particularly to an ink jet printer using an ultraviolet curable ink.
[0002]
[Prior art]
In general, when color printing is performed on a resin packaging material or the like, a method of printing mainly by gravure printing is known. Gravure printing is a printing method in which ink is placed in a recess formed on a printing plate and transferred directly to a recording medium. It can express characters, symbols, pictures, etc. in rich colors, and can be printed on a large number of recording media at high speed. Is the feature. In particular, printing has recently been performed on various packaging materials. In such a case, gravure printing can be said to be a useful printing technique. However, in gravure printing, it is necessary to produce a plate in a pre-process for actually printing, and it takes cost and time to produce this plate. Therefore, when printing a small quantity and a wide variety of products, a means that does not require a plate and can print on a transparent or opaque packaging material in a flexible manner is desired.
[0003]
In this respect, as a means for performing printing on various recording media, conventionally, printing by an ink jet printer is known. An ink jet printer records an image on a recording medium by ejecting ink from nozzles provided on the surface of the recording head facing the recording medium, landing on the recording medium, and fixing the ink. As a method for forming an image even on a recording medium having poor ink absorbability such as a film, a UV inkjet recording method has been conventionally known (for example, see Patent Document 1). This is because an ultraviolet curable ink containing a photoinitiator having a predetermined sensitivity to ultraviolet rays is used, and the ink that has landed on the recording medium is irradiated with the ultraviolet rays so that the ink is cured and fixed on the recording medium. Therefore, printing can be easily performed even on transparent or opaque packaging materials.
[0004]
When printing is performed on a transparent packaging material, printing may be performed on the back side of the packaging material in order to maintain durability against scratching of the printed surface, which is referred to as “back printing”. Further, when printing on an opaque packaging material, printing is performed on the front side of the packaging material, which is called “surface printing”. For example, when printing characters, symbols, pictures, etc., with a white or other special color as a background color on a transparent packaging material, when performing reverse printing, print each color ink first, and then What is necessary is just to print background inks, such as white, and when performing surface printing, background inks, such as white, should be printed first, and color inks of each color should be printed after that.
[0005]
[Patent Document 1]
JP-A-60-132767 [0006]
[Problems to be solved by the invention]
However, when background ink such as white that is printed as a background color is mixed with color ink on a recording medium, unlike when ink is mixed, image blurring and blurring occur, resulting in a decrease in print image quality. There is a risk of inviting. For this reason, it is necessary to completely cure and fix the ink by irradiating ultraviolet rays as soon as possible after the background ink has landed on the recording medium. In order to print background ink such as white as a background color, a background ink recording head must be separately mounted on the carriage. This background ink recording head is used as a color ink recording head. On the other hand, if it is arranged before and after the recording medium conveyance direction, the carriage becomes longer along the recording medium conveyance direction, and the stability of the carriage is lowered. Therefore, it becomes necessary to provide a plurality of guide rails for supporting the carriage, and the structure of the apparatus becomes complicated.
In this case, the platen that is the recording area of the printer must also be provided as wide as the length of the carriage, and it is necessary to maintain the flatness of the entire area. For this reason, when trying to perform stable image recording while maintaining the accuracy of the apparatus, the apparatus becomes larger and more complicated, and the manufacturing cost of the apparatus increases accordingly.
[0007]
Accordingly, the present invention has been made to solve the above-described problems, and provides a small-sized and lightweight inkjet printer that can perform surface printing and back printing while maintaining image quality. It is for the purpose.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 includes a process color recording head for ejecting a process color ultraviolet curable ink on a carriage and a background ink recording head for ejecting a background ultraviolet curable ink. In the serial printing type inkjet printer that is mounted and reciprocally driven in the main scanning direction for recording ,
The background ink recording heads are arranged upstream and downstream of the process color recording head in the main scanning direction, respectively, and ultraviolet rays are irradiated to the upstream and downstream sides of the background ink recording head in the main scanning direction. An ultraviolet irradiation device for curing the ink that has landed on the recording medium is provided.
[0009]
In the first aspect of the invention having such a configuration, the background ink recording head is disposed at a position extending in the main scanning direction of the process color recording head so that the recording head is elongated in the recording medium conveyance direction. This is excellent in that the carriage is stable.
[0010]
In addition, the process color recording heads are provided as a group, the background ink recording heads are arranged at positions separated from the process color recording head groups, and the ultraviolet irradiation device is connected to the main scanning of the background ink recording heads. It is arranged on both the upstream and downstream sides of the direction . Thus, after the background ink is landed, the background ink can be completely cured and fixed before the process color ink is discharged next time.
Further, in the case of a serial print type inkjet printer, surface printing and back printing using background ink can be performed.
In addition, when performing printing using ultraviolet curable ink, high-quality surface printing and back printing can be performed.
[0011]
The invention according to claim 2 is the ink jet printer according to claim 1, wherein the print mode is selected from surface printing, back printing, bidirectional printing, unidirectional printing, or a combination thereof. And a control device that controls the drive of the recording head and the ultraviolet irradiation device according to the selection of the printing mode.
[0012]
Therefore, according to the second aspect of the invention, it is possible to easily perform front printing and back printing using the background ink by selecting a desired printing mode.
[0017]
According to a third aspect of the present invention, in the ink jet printer according to the first or second aspect, the background ink is a white ink.
[0018]
As described above, according to the third aspect of the present invention, since the white ink is used as the background ink, the image printed by the process color can be made more prominent.
[0019]
Furthermore, the invention according to claim 4 is the ink jet printer according to any one of claims 1 to 3, wherein the recording medium on which an image is recorded by the ink is made of a transparent or translucent resin. It is characterized by being a film.
[0020]
As described above, the invention according to claim 4 can perform surface printing and back printing on a transparent or translucent resin film, and therefore can correspond to printing on a soft packaging material. .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
First, as shown in FIG. 1, in the present embodiment, an inkjet printer 1 is an inkjet printer 1 based on a serial printing method, and includes a printer body 2 and a support base 3 that supports the printer body 2 from below. . A platen 7 that supports the recording medium P from the non-recording surface is disposed at the center of the printer main body 2 so as to extend in the longitudinal direction of the printer main body 2. A rod-shaped guide rail 4 extending in the longitudinal direction of the printer main body 2 is provided upstream in the conveying direction. A carriage 5 is supported on the guide rail 4 so as to be reciprocally driven along the guide rail 4 by a driving mechanism (not shown). Here, the reciprocating direction of the carriage 5 is X, and the conveyance direction of the recording medium P is the sub-scanning direction Y.
[0022]
As shown in FIGS. 1 and 2, there are four colors (yellow (Y), magenta (M), cyan (C), black used in the ink jet printer 1 in the present embodiment at the center of the carriage 5. (K). Two sets of four recording heads 10a corresponding to the ink of process color (hereinafter referred to as process color) are provided, one of which is located upstream in the sub-scanning direction Y and the other is sub-scanning. The positions are shifted from each other so as to be located on the downstream side in the direction Y.
[0023]
On both sides of the process color recording head 10a, two white ink recording heads 10b for discharging background white ink are provided as a group, one of which is upstream of the sub-scanning direction Y. The other one is arranged so as to be shifted from each other so that the other one is located downstream in the sub-scanning direction Y. In this embodiment, white ink is used as the background ink, but the ink is not limited to white ink as long as it is suitable for background printing.
[0024]
Each recording head 10 is formed in a substantially rectangular parallelepiped shape, and is arranged side by side in the main scanning direction X so that the longitudinal directions thereof are parallel to each other. In addition, a plurality of nozzles 11 that eject ink are formed in series in the longitudinal direction of the recording head 10 on the surface of each recording head 10 that faces the recording surface of the recording medium P.
[0025]
The carriage 5 is provided with a number of intermediate tanks 12 for storing ink and supplying ink to the recording head 10 corresponding to the recording heads 10a and 10b. Each recording head 10 supplies ink to the intermediate tank 12 and the ink supply. Communication is made via a pipe 13. The intermediate tank 12 communicates with an ink tank 8 provided outside the platen 7 at one end of the moving range of the carriage 5 through an ink supply path (not shown). Note that a range where the carriage 5 is movable and above the ink tank 8 is a home position area (not shown) serving as a standby place for the carriage 5. A maintenance unit 9 for performing a maintenance operation of the recording head 10 is disposed at the other end of the moving range of the carriage 5 and at a position opposite to the ink tank 8 with the platen 7 interposed therebetween.
[0026]
Inside the carriage 5 between the background ink recording head 10b and the side wall of the carriage 5 and between the background ink recording head 10b and the process color ink recording head 10a One ultraviolet irradiation device 14 for irradiating the ink landed on the ink with ultraviolet rays is provided.
[0027]
The ultraviolet irradiation device 14 includes a cover member 16 formed in a concave shape having an opening on one end surface, and the opening of the cover member 16 is disposed so as to face the recording surface of the recording medium P. Further, the upper surface of the cover member 16 that is formed substantially parallel to the recording surface of the recording medium P is a rod-like shape that radiates ultraviolet rays that cure and fix the ultraviolet curable ink that has landed on the recording medium P. A plurality of ultraviolet light sources 15 are provided, and the respective ultraviolet light sources 15 are arranged so that their longitudinal directions are parallel to each other. As the ultraviolet light source 15, a light source such as a high pressure mercury lamp, a metal halide lamp, a hot cathode tube, a cold cathode tube, or an LED is used.
[0028]
Next, the control device in the present embodiment will be described with reference to FIG. The printer main body 2 is provided with an input device 17 for selecting the type of printing, and this input device 17 is connected to a control device 18 that receives the input information and controls each part of the printer. The input device 17 is, for example, a keyboard or an operation panel, and can select a printing mode such as one-side printing for front printing, two-way printing for front printing, one-way printing for back printing, and two-way printing for back printing. The control device 18 also includes an interface 19 for transferring image data and control data input from the input device 17 to each unit, a recording head control unit 21 for outputting each of the recording heads 10 provided with a plurality of image data, and printing. And an ultraviolet irradiation control unit 22 for switching the ultraviolet irradiation device 14 that operates according to the type of the CPU, and has a CPU 20 connected to all of them.
[0029]
Next, the operation of the present embodiment will be described with reference to FIG.
When the print mode is selected from the input device 17, this information is sent as an electrical signal to the CPU 20 in the control device 18 through the interface 19. Upon receiving this signal, the CPU 20 transmits information such as printing conditions to the ultraviolet irradiation controller 22 and the recording head controller 21. The ultraviolet irradiation control unit 22 turns on the ultraviolet light source 15 of the ultraviolet irradiation device 14 that matches the printing mode selected based on the transmitted information, and the carriage 5 moves on the recording medium P by a driving device (not shown) in the main scanning direction. Reciprocate along X. At this time, the recording head control unit 21 receives ink from the process color recording head 10a and the white ink recording head 10b so as to meet the selected printing condition among the recording heads 10 mounted on the carriage 5. Discharge onto P. An image is recorded on the recording medium P by being irradiated with ultraviolet rays from the ultraviolet light source 15.
[0030]
For example, when the front printing one-way printing mode is selected from the input device 17, this information is sent to the CPU 20 in the control device 18 and further sent to the ultraviolet irradiation control unit 22 and the recording head control unit 21. As a result, the ultraviolet irradiation control unit 22 transmits an instruction to the ultraviolet irradiation control device 14, and as indicated by hatching in FIG. 5A, the ultraviolet irradiation device 14 disposed on both sides of the process color recording head 10a. The ultraviolet light source 15 is turned on. When the carriage 5 moves in the forward path A direction, white ink is ejected from the nozzles 12 of the recording head 10b located on the upstream side in the forward path A direction, as indicated by the oblique lines in FIG. The ink landed on the medium P is irradiated with ultraviolet rays from the ultraviolet light source 15 in the ultraviolet irradiation device 14 adjacent to the downstream side in the forward direction A of the recording head 10b to cure and fix the white ink. Thereafter, ink of a predetermined color is ejected from the process color recording head 10a based on predetermined printing information, and ultraviolet rays are irradiated from the ultraviolet light source 14 provided in the ultraviolet irradiation device 13 adjacent to the downstream side of the recording head 10a. Then, the process color ink is cured and fixed. While the carriage 5 returns to the home position area (return path B), the recording medium P is conveyed in the conveyance direction. When the conveyance is completed and the recording medium P is stopped, the printing operation is repeated again.
[0031]
Next, when the front printing bidirectional printing mode is selected, as in the case where the front printing one-way printing mode is selected, the process color recording head 10a as shown by hatching in FIG. 5B. The ultraviolet light source 15 of the ultraviolet irradiation device 14 disposed on both sides of the LED is turned on. When the carriage 5 moves in the forward path A direction, white ink is ejected from the nozzles 12 of the recording head 10b located on the left side in the forward path A direction, and the recording head 10b is applied to the ink landed on the recording medium P. The ultraviolet light is irradiated from the ultraviolet light source 15 in the ultraviolet irradiation device 14 adjacent to the downstream side in the forward path A direction to cure and fix the white ink. Thereafter, ink of a predetermined color is ejected from the process color recording head 10a based on predetermined printing information, and from an ultraviolet light source 15 provided in the ultraviolet irradiation device 14 adjacent to the downstream side in the forward path A direction of the recording head 10a. Ultraviolet rays are irradiated to cure and fix the process color ink. In the return path B, white ink is ejected from the nozzles 12 of the recording head 10b positioned on the return path B side in the carriage 5, and the ink landed on the recording medium P is downstream of the recording head 10b in the return path B direction. Ultraviolet light is irradiated from an ultraviolet light source 15 in the adjacent ultraviolet irradiation device 14 to cure and fix the white ink. Thereafter, ink of a predetermined color is ejected from the process color recording head 10a based on predetermined printing information, and from an ultraviolet light source 15 provided in the ultraviolet irradiation device 14 adjacent to the downstream side in the return path B direction of the recording head 10a. Ultraviolet rays are irradiated to cure and fix the process color ink.
[0032]
When the back-printing one-way printing mode is selected, as shown in FIG. 5C, the ultraviolet irradiation device disposed on both sides of the white ink recording head 10b located on the return path B side in the carriage 5. 14 ultraviolet light sources 15 are turned on. Then, an ink of a predetermined color is ejected from the process color recording head 10a based on predetermined printing information, and an ultraviolet ray adjacent to the downstream side in the forward direction A of the recording head 10a with respect to the ink landed on the recording medium P. The process color ink is cured and fixed by being irradiated with ultraviolet rays from an ultraviolet light source 15 provided in the irradiation device 14. Thereafter, white ink is ejected from the background recording head 10b indicated by diagonal lines in FIG. 5C, and ultraviolet rays are emitted from the ultraviolet light source 15 provided in the ultraviolet irradiation device 14 adjacent to the downstream side in the forward path A direction of the recording head 10b. As a result, the white ink is cured and fixed. Then, while the carriage 5 returns to the home position (return path B), the recording medium P is conveyed in the conveyance direction Y, and when the conveyance is completed and the recording medium P is stopped, the above printing operation is repeated.
[0033]
Further, when performing reverse printing bidirectional printing, as shown in FIG. 5D, the ultraviolet light sources 15 of all the ultraviolet irradiation devices 14 mounted on the carriage 5 are turned on. First, ink of a predetermined color is ejected from the process color recording head 10a based on predetermined printing information, and is adjacent to the downstream side of the recording head 10a in the forward direction A with respect to the ink landed on the recording medium P. Ultraviolet light is irradiated from an ultraviolet light source 15 provided in the ultraviolet irradiation device 14. As a result, the process color ink is cured and fixed. Thereafter, white ink is ejected from the background recording head 10b mounted on the return path B side in the carriage 5, and from the ultraviolet light source 15 provided in the ultraviolet irradiation device 14 adjacent to the downstream side of the recording head 10b in the forward path A direction. Ultraviolet rays are irradiated. As a result, the white ink is cured and fixed. When the recording medium P stops after the recording medium P has been transported for the portion where the image is recorded, the carriage 5 moves in the return path B direction, and a predetermined color based on predetermined printing information from the process color recording head 10a. Color ink is ejected, and ultraviolet light is irradiated from an ultraviolet light source 15 provided in an ultraviolet irradiation device 14 adjacent to the downstream side in the return path B direction of the recording head 10a to cure and fix the process color ink. Thereafter, white ink is ejected from the nozzle 12 of the recording head 10 b located on the forward path A side in the carriage 5. Then, the ink landed on the recording medium P is irradiated with ultraviolet rays from the ultraviolet light source 15 in the ultraviolet irradiation device 14 adjacent to the downstream side in the return path B direction of the recording head 10b to cure and fix the white ink.
[0034]
In the present embodiment, the inkjet printer 1 is capable of selectively performing each printing mode of front-printing unidirectional printing, front-printing bidirectional printing, back-printing unidirectional printing, and back-printing bidirectional printing. However, the specification of the printer may be limited to front printing, for example, or may be limited to one-side printing for front printing and back printing.
When the print mode is limited as described above, it is not necessary to turn on a part of the ultraviolet light source 15 in the carriage 5, so that the ultraviolet irradiation device 14 having the ultraviolet light source 15 is not mounted on the carriage 5. You can also. In such a configuration, the carriage 5 can be further reduced in size and weight.
[0035]
In the present embodiment as described above, since the recording head 10b for the white ink as the background color is arranged on both sides of the recording head 10a for the process color ink, the carriage 5 becomes longer in the sub-scanning direction Y side. Therefore, even if the recording head 10b for white ink and the recording head 10a for process color ink are mounted in the same carriage 5, the stability of the carriage 5 can be maintained. Further, it is sufficient that the platen 7 can maintain the flatness by the width of the carriage 5. For this reason, it is possible to reduce the size and weight of the apparatus and simplify the structure of the apparatus, and as a result, it is possible to reduce the apparatus cost.
[0036]
Further, since the white ink for background causes blurring of the image when mixed with the process color ink, it needs to be completely cured immediately after landing on the recording medium P. However, in this embodiment, the recording for white ink is necessary. Since the ultraviolet irradiation device 14 is arranged on both sides of the head 10b, the white ink can be completely cured and fixed after the background ink is landed and before the next process color ink is ejected. Does not cause degradation of image quality.
[0037]
Further, by selecting a print mode such as front-printing unidirectional printing or reverse-printing unidirectional printing, the control device 18 drives the recording head 10 and the ultraviolet irradiation device 14 most suitable for each printing mode. Only the ultraviolet ray irradiation device 14 that can effectively cure and fix the ink ejected from the recording heads 10 and the recording heads 10 necessary for performing the printing, and the surface printing using the background ink and Back printing can be performed efficiently.
[0038]
【The invention's effect】
As described above, according to the first aspect of the present invention, the carriage having the recording head mounted thereon by disposing the background ink recording head at a position extending in the main scanning direction of the process color recording head. It does not become long in the recording medium conveyance direction. Therefore, the carriage can be stabilized without providing a plurality of guide rails, and the platen only needs to maintain flatness by the width of the carriage, so that the apparatus can be reduced in size and weight, and the apparatus structure can be simplified. As a result, the apparatus cost can be reduced.
[0039]
Further, by arranging the ultraviolet irradiation devices on both the upstream side and the downstream side in the main scanning direction of the background ink recording head, the background ink can be cured and fixed at an early stage after ink landing . For this reason, when printing is performed using an ultraviolet curable ink by a serial printing ink jet printer , the background ink does not mix with the process color ink, and the printing image quality such as image bleeding does not deteriorate. is there.
[0040]
Next, according to the second aspect of the invention, by selecting a desired print mode, the most suitable recording head and ultraviolet irradiation device for each print mode are selected and driven. There is an effect that surface printing and back printing using ink can be efficiently and effectively performed.
[0043]
Next, according to the third aspect of the invention, since the white ink is used as the background ink, the image printed by the process color can be made more prominent when the front printing and the back printing are performed. There is an effect that can be.
[0044]
Furthermore, since the invention according to claim 4 can perform surface printing and back printing on a transparent or translucent resin film, a high-quality image can be obtained even when printing on a soft packaging material. There is an effect that the formation can be performed.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a configuration of a main part of an embodiment of an ink jet printer according to the present invention.
FIG. 2A is a perspective view showing a carriage provided in the ink jet printer of FIG. FIG. 2B is a bottom view of the carriage of the ink jet printer shown in FIG.
FIG. 3 is a schematic diagram illustrating an arrangement of a recording head and an ultraviolet irradiation device provided in a carriage.
FIG. 4 is a principal block diagram showing an outline of a control device according to the present embodiment.
FIGS. 5A to 5D are schematic views showing driving states of the ultraviolet irradiation device and the background ink recording head in each printing mode of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Printer main body 3 Support stand 4 Guide rail 5 Carriage 7 Platen 8 Ink tank 9 Maintenance unit 10a, b Recording head 11 Nozzle 12 Intermediate tank 13 Ink supply pipe 14 Ultraviolet irradiation device 15 Ultraviolet light source 16 Cover member 17 Input device 18 Control device 19 Interface 20 CPU
21 Recording head controller 22 Ultraviolet irradiation controller P Recording medium X Main scanning direction Y Recording medium conveyance direction

Claims (4)

Equipped with the background ink recording head for ejecting ultraviolet curable inks for process color printing head and the background for ejecting ultraviolet curable ink of process color on the carriage, the serial print performing recording reciprocating to the main scanning direction In the inkjet printer of the type,
The background ink recording heads are arranged upstream and downstream of the process color recording head in the main scanning direction, respectively, and ultraviolet rays are irradiated to the upstream and downstream sides of the background ink recording head in the main scanning direction. An ink jet printer comprising an ultraviolet irradiation device for curing ink landed on a recording medium. As the printing mode, it is possible to select front printing, back printing, bidirectional printing, unidirectional printing, or a combination thereof, and according to the selection of this printing mode, the recording head and the ultraviolet irradiation device The inkjet printer according to claim 1, further comprising a control device that controls driving. The background ink jet printer according to claim 1 or claim 2 characterized in that it is a white ink. The ink jet printer according to any one of claims 1 to 3, wherein the recording medium on which an image is recorded by the ink is a transparent or translucent resin film.

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