JP6162548B2 - Ultraviolet irradiation device in printer - Google Patents

Description

  The present invention relates to an ultraviolet irradiation device in a printer that discharges ultraviolet curable ink from an inkjet print head and performs printing on a printing medium.

2. Description of the Related Art Conventionally, inkjet printers that print on media such as paper using ultraviolet curable ink and cure the ink by irradiating the printed ink with ultraviolet rays (see, for example, Patent Documents 1 and 2). .
Patent Document 1 discloses an ink jet recording apparatus in which an ultraviolet light emitting diode (UVLED) is turned on only in a portion corresponding to an ink discharge nozzle of a print head and a UVLED is turned off in a portion not printed.
Patent Document 2 discloses an ink jet printer having a configuration in which a light illumination device having a wider range than the print head is provided above the print head and the light irradiation range is changed according to the print mode.

JP 2004-237588 A JP 2004-299267 A

When an ultraviolet curing light source is attached to the printer body over the entire width of the print surface of the print medium, the printed ink is immediately irradiated from the light source, so that printing with a grainy feel is possible. Although obtained, the ink is cured before being smoothed, so that there is a problem that it is not suitable when a glossy printing result (smoothed printing) is desired.
The present invention aims to solve the above problems.

To achieve the above object, the present invention provides a head guide rail supported on the machine body side, a print head provided on a head carriage movably attached to the head guide rail, and a support means for supporting a print medium. And the relative movement of the head carriage and the print medium in the main scanning direction and the sub-scanning direction under the control of the controller, and the UV curable ink is ejected from the print head to discharge the main print medium. In a printer that performs printing in an area in the scanning direction, the printer includes an ultraviolet irradiation light source that extends along the longitudinal direction of the head guide rail attached to the head guide rail side, and a light source controller 18 that controls the light source, The ultraviolet irradiation light source has a configuration in which a plurality of ultraviolet LED chips are arranged, and is arranged along the head guide rail of the head carriage. Following the movement, after the ink droplets ejected from the print head have landed on the print medium, the LED chip whose irradiation range is the landed ink droplets is extinguished for a certain period of time until a certain period of time elapses The ultraviolet LED chip of the ultraviolet irradiation light source is controlled by the light source controller so that the ultraviolet light is not irradiated to the ink after landing.
Further, the present invention is characterized in that ultraviolet rays are not irradiated to a print area in a predetermined range behind the print area of the print medium facing the ink ejection surface of the print head with respect to the main scanning direction. .
Further, according to the present invention, ultraviolet rays are not irradiated to a print area of the print medium facing the ink ejection surface of the print head and a print area in a predetermined range behind the print area with respect to the main scanning direction. It is characterized by.
According to the present invention, the ultraviolet irradiation light source includes an LED light emitting unit including a plurality of ultraviolet LED chips arranged in the width direction of the print medium, and a cover for holding the LED light emitting unit. A light transmission part for guiding the ultraviolet rays to be emitted toward the printing medium is provided.

In the present invention, after the ink droplets ejected from the print head have landed on the print medium, the LED chip whose irradiation range is the landed ink droplets is extinguished for a certain period of time, and the ink after landing until the certain period of time elapses. Since it is possible to obtain time for the ink to be smoothed on the surface of the print medium by not irradiating the ultraviolet light, controlling the time until the ink is irradiated with light and printing with a grainy feel and gloss You can freely create smoothed prints.
In addition, the power consumption of the light source can be reduced by turning off part of the light source at the position where the print surface facing the ink ejection surface of the print head and the print surface located behind the print surface in the main scanning direction are turned off. The effect of reducing heat generation can be obtained.

FIG. 3 is an explanatory plan view of the printer according to the present invention. It is explanatory drawing of this invention. It is an external view of a printer. It is side surface explanatory drawing of a printer. It is side surface explanatory drawing of the printer which shows other embodiment of this invention. It is side surface explanatory drawing of the printer which shows other embodiment of this invention. It is side surface explanatory drawing of the printer which shows other embodiment of this invention. It is block circuit explanatory drawing of this invention. It is explanatory drawing which shows other embodiment of this invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
1 and 3 show a first embodiment. Reference numeral 2 denotes a head guide rail of the ink jet printer, which is fixed to the body (not shown) via a support. Reference numeral 4 denotes a head carriage, to which an ink jet print head 6 (see FIG. 4) is attached. The head carriage 4 is connected to the head guide rail 2 so as to reciprocate in the main scanning direction Y (Y-axis direction) along the head guide rail 2.

A plurality of ink ejection nozzle rows are provided on the ink ejection surface of the print head 6. The nozzle rows are arranged in parallel on the ink ejection surface at the bottom of the print head 6 so that the print areas in the main scanning direction overlap each other. A region on the print medium 8 facing the movement path of the ink ejection surface at the bottom of the print head 6 forms a scanning surface D. A plurality of ultraviolet curable ink sub-tanks are attached to the head carriage 4, and ink is supplied to the sub-tanks from an ink cartridge disposed on the machine body side by a tube. The sub tank and the nozzle row of the print head 6 corresponding to these are connected through a tube.

A platen 10 is provided below the head guide rail 2, and the print medium 8 is conveyed on the platen 10 from right to left in FIG. In the horizontal portion of the platen 10, a slit is formed along the head guide rail 2, and a driving roller 12 is disposed in the slit. The printing medium 8 on the platen 10 is sandwiched between the driving roller 12 and a pressing roller 14 provided on the head guide rail 2 side, and the platen 10 is rotated at a predetermined pitch in the sub-scanning direction by the rotation of the driving roller 12. It is comprised so that it may be conveyed by.

On the side surface of the head guide rail 2, a rod-like ultraviolet irradiation light source 16 extending in the main scanning direction Y is disposed so as to be located over substantially the entire movement range of the head carriage 4 along the head guide rail 2. 16 is connected to the head guide rail 2 via a support (not shown) or directly. FIG. 3 shows an embodiment in which one light source 16 is attached to the head guide rail 2, and FIG. 4 shows an embodiment in which two light sources 16 are arranged vertically. In FIG. 4, the left side is the front side of the printer body and the right side is the rear side of the printer body, and the print head 6 is disposed on the front side of the machine body with respect to the head guide rail 2.

The ultraviolet irradiation light source 16 has a box-shaped cover (not shown), and an ultraviolet (UV) light emitting unit 16a is stored inside the cover, and an ultraviolet irradiation that defines the irradiation direction of the ultraviolet rays is provided at the bottom of the cover. A window (light transmission portion) is formed over substantially the entire length of the cover. The UV light emitting unit 16a constituting the light source 16 includes, as a constituent element, one or a plurality of LED bodies each having a plurality of LED (light emitting diode) chips 16b arranged linearly in the main scanning direction. In addition, the arrangement | sequence of a chip | tip etc. which arranged the chip | tip alternately on the right and left of a straight line other than rod shape can be employ | adopted, and the arrangement | sequence of a chip | tip is not specifically limited to rod shape. The UV light emitting unit 16a is connected to the printer main unit via a UV lamp drive control unit including a light source controller 18 (see FIG. 8) and a driver circuit 20 so that the light quantity and on / off control of each LED chip 16b can be controlled. It is connected to the controller 22.

An address number given in advance is used for on / off control and light amount designation of each LED chip 16b of the UV light emitting unit 16a, and an on / off signal and illuminance for each LED chip are transmitted from the main controller 22 to the light source controller 18. Based on the supplied data, the light source controller 18 drives each LED chip 16b of the UV light emitting unit 16a by the PWM method or the like via the driver circuit 20.

  The UV light emitted from the light source 16 is configured to irradiate the scanning surface D of the printing medium 8 on the platen 10 facing the moving path of the ink ejection surface of the print head 6. Here, the scanning surface D is a region having a width corresponding to the printing width of the print head 6 and extending in the entire width direction of the print medium 8 along the movement path of the ink discharge surface of the print head 6 in the main scanning direction. The print head 6 moves along the head guide rail 2 on the scanning plane D in the main scanning direction Y, and performs printing for one band on the scanning plane D.

Next, the operation of this embodiment shown in FIGS. 1 and 3 will be described.
The print head 6 moves from the home position set to the side (for example, the left side) of the print medium 8 to the standby position that approaches the side of the print medium 8 in the horizontal direction, and from the standby position, for example, to the right It moves while ejecting CMYK (cyan, magenta, yellow, black) UV curable ink from the ink ejection surface in the main scanning direction, and first prints one band on the printing medium 8. When printing for one band is completed, the print head 6 returns to the standby position on the left side of the print medium 8, and the print medium 8 moves in the sub-scanning direction for one band.

  Next, the print head 6 moves to the right from the standby position, and uses the two divided areas of the nozzle array on the print medium 8 to print the previously printed one band area and the new one band area. Color printing is performed. At this time, the second-pass printing is overlaid on the first one-band printing area. When 4-pass color printing is performed in the above manner, printing for the first band is completed, and printing is sequentially performed on the print medium 8 in this manner. The above printing method is a four-pass method, but there are various printing methods such as a one-pass method, and the present invention is not particularly limited to the four-pass method. In addition, various printing methods such as one-side printing and two-way printing are used depending on the application.

In the printing operation by the print head 6, if the position of the print head 6 shown in FIG. 1A is the print start position, the print head 6 is discharged along the head guide rail 2 while ejecting ink in this state. Move to the right in the scanning direction. At the printing start position, the light source 16 is turned on except for a part thereof, and the scanning surface D of the printing medium 8 is irradiated with UV light from the rear side of the machine body with reference to the movement path of the printing head 6. At this time, the light source controller 18 is located on the back side of the head carriage 4 and has an ultraviolet irradiation range with respect to the scanning surface D in a range facing the ink ejection surface of the print head 6. The LED chip 16 shown in black is turned off so that UV light is not irradiated to the ink droplet P landed on the scanning surface D in the range facing the ink ejection surface of the print head 6, and the front of the light source 16 is Irradiation to the moving head carriage 4 is no longer performed, so that the temperature rise with respect to the head carriage 4 is also suppressed. In addition, since the head carriage 4 is a wall, the ink is not directly irradiated with light, but it is possible to prevent the light from wrapping around when the light is turned off. It should be noted that the light under the print head 6 is not easily hit by the head carriage 4 or the like, so that this portion does not necessarily need to be turned off if only smoothing is performed.

FIG. 1B shows a state in which the print head 6 has moved to the right. In this state, the light source controller 18 is located on the back side of the head carriage 4, that is, in the ink ejection area of the print head 6. The LED chip 16b having an irradiation range and the LED chip 16b having a light irradiation range in a predetermined area B outside the ink discharge area behind the ink discharge area are extinguished, and on the print medium 8, The ultraviolet ray is prevented from being irradiated to the ink discharge area A by the print head 6 and the area B in the predetermined range behind the ink discharge area A in the moving direction of the head carriage 4. In FIG. 1B, the unlit LED chip 16b is shown in black.

FIG. 1C shows a state in which the print head 6 further travels in the main scanning direction. In this state, the LED chip 16b having an irradiation range in the ink ejection area A and the area B behind the print head 6 is provided. Turns off. Irradiation with ultraviolet rays is performed on a predetermined region C further printed after. When the printer is a bi-directional printing method, the LED chip is turned on / off similarly to the above operation, and the ink ejection area of the print head 6 and a predetermined area behind it are followed by the movement of the head carriage 4. The LED chip 16b having the irradiation range is turned off, and the LED chip 16b having the irradiation range is turned on on the scanning plane D in the other region.

FIG. 2 shows the state of the ink droplets P in each region on the print medium 8, and the ink droplets P immediately after ink landing are raised from the surface of the print medium 8 as shown in FIG. 2A. It has a certain granular shape. As shown in FIG. 2B, the raised granular state changes to a flat state as time passes. This change is large in the state where the ultraviolet rays are not irradiated, and when the ultraviolet rays are irradiated, the ink is cured and then the ink is cured. FIG. 2C shows a state in which ultraviolet rays are applied to the ink droplets after smoothing and smoothing after the ink droplets have landed.

In this embodiment, the width in the main scanning direction of the extinguishing area behind the ink ejection area is set to be the same as the width in the main scanning direction of the ink ejection area, but this width can be arbitrarily set and is the same The width is not limited. If you want to print with a grainy feel, you can reduce the range to irradiate early, and if you want to print glossy, you need to irradiate after smoothing, so increase the range. It ’s fine. This range may be arbitrarily determined based on the relationship between the carriage speed and the specifications of the ink used (viscosity, etc.). In addition, if you prepare several parameters for the required combinations in the printer and select them according to the required printing results, you can arbitrarily obtain glossy prints or grainy prints. It becomes like this.
As described above, the LED chip having an irradiation range with respect to the print surface facing the back side of the moving head carriage 4 and facing the discharge surface of the print head 6, and the predetermined rear side of the print surface facing the discharge surface The LED chip having the irradiation range with respect to the printing surface of the range is turned off under the control of the light source controller 18, thereby reducing the power consumption and heat generation of the light source 16.

The operation of the embodiment in which two light sources 16 of FIG. 4 are provided is the same as the operation of the above embodiment.
FIG. 5 shows an embodiment in which the light source 16 is arranged directly above the print head 6 via the fixture 24.
During the printing operation of the printer, the LED chip having an irradiation range with respect to the print surface facing the discharge surface of the print head 6 of the light sources 16 and 16 and the print surface in a predetermined range behind the print surface facing the discharge surface The LED chip having the irradiation range is turned off under the control of the light source controller 18, and the LED chip having the irradiation range with respect to the printing surface in the other range is turned on under the control of the light source controller 18.
Other configurations are the same as those of the embodiment shown in FIG.
FIG. 6 shows an embodiment in which the light sources 16 and 16 are arranged on the front side of the machine body with reference to the movement path of the head carriage 4 via the fixture 26.

During the printing operation of the printer, the LED chip having an irradiation range with respect to the printing surface of the light source 16, 16 facing the ink ejection surface of the print head 6 and the printing of a predetermined range behind the printing surface facing the ink ejection surface The LED chip having an irradiation range with respect to the surface is turned off under the control of the light source controller 18.
The other part of the light source 16 irradiates the scanning surface D of the print medium 8.

As shown in FIGS. 4 and 6 of this embodiment, when the irradiation is from the lower part instead of the irradiation from the upper part as shown in FIG. 5, the printing medium 8 can be printed even if the light amount is small because the distance to the print medium 8 is short. Since the amount of light at the time of reaching the medium can be obtained, it is possible to use a light source having a lower ability than when irradiating from above. The other configuration of the embodiment shown in FIG. 6 is the same as that of the embodiment shown in FIG.
FIG. 7 shows an embodiment in which the present invention is applied to a head guide rail moving type printer.

  The head guide rail 2 is supported by the printer body so as to be movable in the left-right direction (sub-scanning direction) in the drawing. In the printing operation, the head guide rail 2 moves relative to the print medium 8 on the support base 28 in the sub-scanning direction, the head carriage 4 moves relative to the head guide rail 2 in the main scanning direction, and the print head 6 Ink is ejected from the scanning surface of the printing medium 8 to perform printing.

A rod-shaped light source 16 is disposed on the lower surface of the head guide rail 2.
During the printing operation of the printer, the LED chip having an irradiation range with respect to the scanning surface of the printing medium 8 facing the ink ejection surface of the print head 6 and the scanning surface of a predetermined range behind the scanning surface facing the ejection surface. The LED chip having the irradiation range is turned off under the control of the light source controller 18. The other part of the light source 16 irradiates the scanning surface of the print medium 8.

In the printer, the head guide rail 2 is usually attached with a pressing roller for sandwiching the print medium 8 with the driving roller. However, since the head guide rail drive type printer as in this embodiment does not include a pressing roller on the head guide rail 2, a bar-shaped light source is directly opposed to the scanning surface of the print medium on the lower surface of the head guide rail 2. 16 can be attached. In FIG. 7, the print surface moves to the irradiation range of the light source 16 by moving the head guide rail 2 to the left side. When the light source 16 is provided on the opposite side of the head as shown in FIG. 6, the movement direction of the head guide rail 2 is rightward, and therefore the relative conveyance direction of the head guide rail 2 with respect to the print medium 8. May be either in this embodiment.
Other configurations are the same as those of the embodiment shown in FIG.

FIG. 9 shows an embodiment in which the irradiation ranges of the upper and lower light sources 16 and 16 are changed.
As shown in FIG. 9A, the lower light source 16 is set so that the irradiation range A coincides with the print range A on the print medium 8, and the upper light source 16 is shown in FIG. 9B. As shown, the irradiation range B includes a printing range A, and is further set to a range extending a predetermined range ahead of the machine body. That is, in the embodiment of FIG. 9, the upper light source 16 irradiates an area wider than the printing range A, and the lower light source 16 irradiates the printing range A (scanning surface D). The irradiation range of the light source 16 at each stage is adjusted by the angle of irradiation with the lens of the light transmission part of the cover of the light source 16. Irradiation by the lower light source 16 is suitable for irradiation immediately after printing because the distance from the scanning surface is short and the irradiation range is narrow, so that the amount of light increases. In addition, irradiation over a wide range by the upper light source 16 increases the integrated light amount on the printing surface of the printing medium.

The irradiation range of the upper and lower light sources 16 is not particularly limited to the illustrated range, and can be set as appropriate. The light source 16 is not limited to the upper and lower two stages, and a plurality of stages can be arranged.
In the configuration described above, during the printing operation by the print head 6, the light sources 16 and 16 are turned on except for a part, and the scanning surface D of the printing medium 8 corresponding to the printing width of the printing head 6 and the scanning surface D From the rear side of the machine, UV light is irradiated to an area within a predetermined range located in front of the machine from the rear side of the machine with reference to the movement path of the print head 6.

Further, during the printing operation of the printer, the LED chip having an irradiation range with respect to the scanning surface facing the ink ejection surface of the print head 6 and the scanning surface in a predetermined range behind the scanning surface facing the ejection surface in the main scanning direction The LED chip having an irradiation range is turned off under the control of the light source controller 18.
This prevents UV light from being irradiated to the ink droplets that have not yet landed on the surface of the print medium 8 immediately after being ejected from the print head 6 and the ink droplets that have landed for a certain period of time.

  In the above embodiment, when attention is paid to the conveyance speed of the print medium 8 in the sub-scanning direction, it is considerably slower than the moving speed of the head carriage 4 in the main scanning direction. In general, ultraviolet curable inks have peak illuminance and integrated illuminance as curing conditions. Therefore, in the case of the above embodiment, it is possible to irradiate ultraviolet rays for a long time as compared with the method in which the light source is mounted on the head carriage and moved.

For this reason, it is possible to use a light source with low illuminance compared to the method of moving with the head carriage, and even with a light source with low illuminance, irradiation is performed for a long time, so that the same effect can be obtained as the integrated light amount. Therefore, there is a cost advantage that an expensive light source is not required. In addition, the fact that the amount of light from the light source is small has the advantage that the amount of heat generated from the light source is also low, so that an increase in temperature can be suppressed. Furthermore, for bidirectional drawing, it is usually necessary to mount light sources on the left and right sides of the head carriage.

However, in this embodiment, since the light source is attached to the head guide rail side, an increase in weight does not occur on the head carriage side, which is advantageous in terms of speeding up the head carriage and controlling the ejection position.
In the above description, the expression “printing” is used synonymously with printing. The print medium is not limited to paper, but may be made of various materials such as resin, plastic, metal, etc. In particular, it can also be printed on plate-like materials.

2 Head guide rail 4 Head carriage 6 Print head 8 Print medium 10 Platen 12 Driving roller 14 Pressing roller 16 Light source 16a UV light emitting unit 16b LED chip 18 Light source controller 20 Driver circuit 22 Main controller 24 Mounting tool 26 Mounting tool 28 Stand 32 Fan 34 Exhaust port

Claims (4)

  A head guide rail supported on the machine body side; a print head provided on a head carriage movably attached to the head guide rail; and a support means for supporting a print medium. In a printer that relatively moves the positional relationship between the carriage and the printing medium in the main scanning direction and the sub-scanning direction, discharges ultraviolet curable ink from the print head, and prints in the area of the printing medium in the main scanning direction. An ultraviolet irradiation light source extending along the longitudinal direction of the head guide rail attached to the head guide rail side; and a light source controller for controlling the light source, wherein the ultraviolet irradiation light source is arranged with a plurality of ultraviolet LED chips. The print head following the movement of the head carriage along the head guide rail. After the ejected ink droplets land on the print medium, the LED chip whose irradiation range is the landed ink droplets is extinguished for a certain period of time, and ultraviolet light is not irradiated to the landed ink until a certain period of time elapses. An ultraviolet irradiation device in a printer, wherein the ultraviolet LED chip of the ultraviolet irradiation light source is controlled by the light source controller.   The ultraviolet ray is not irradiated to a print area in a predetermined range behind the print area of the print medium facing the ink ejection surface of the print head in the main scanning direction. UV irradiator for printers.   The ultraviolet ray is prevented from being irradiated to a print area of the print medium facing the ink ejection surface of the print head and a print area in a predetermined range behind the print area with respect to the main scanning direction. Item 6. An ultraviolet irradiation device in a printer according to Item 1.   The ultraviolet irradiation light source is composed of an LED light emitting unit composed of ultraviolet LED chips arranged in the width direction of the print medium, and a cover for holding the LED light emitting unit, and the ultraviolet ray emitted from the LED light emitting unit is printed on the cover. The ultraviolet irradiating device for a printer according to claim 1, further comprising a light transmitting portion for guiding the light toward the head.

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