JP2023174179A - Printing apparatus - Google Patents

Abstract

To provide a printing apparatus capable of reducing the possibility of non-ejection of ink due to irradiation of reflected light while improving the utilization efficiency of light from light sources.SOLUTION: A printing apparatus includes: a platen which supports a medium to be printed; ejection heads which move in a movement direction and eject ultraviolet curable ink onto the medium to be printed; and light sources which move in the movement direction, are disposed at a position different from those of the ejection heads in the movement direction, and emit light for curing the ultraviolet curable ink. The light source has a side surface disposed on the light source side and a reflecting plate provided on the side surface and extending downward from the lowermost part of the light source. The lowermost part of the light source is disposed at a position higher than the lowermost part of the ejection head with respect to the platen.SELECTED DRAWING: Figure 6

Description

The present invention relates to a printing device such as an inkjet printer.

Patent Document 1 discloses that a shielding portion having a retroreflective surface is provided between an ejection head and a light source. In the printing device of Patent Document 1, light that is reflected by a printing medium and the like and reaches a retroreflective surface is reflected by the retroreflective surface, and the reflected retroreflected light reirradiates the printing medium and the like. Therefore, the utilization efficiency of light irradiated to the irradiation area for curing the photocurable ink becomes high. Furthermore, since the utilization efficiency of the light emitted from the light source is increased, it becomes possible to reduce the amount of light emitted. According to the company, this makes it possible to reduce the power consumption of the printing device.

Further, Patent Document 2 describes a discharge head, two light sources provided on the left and right sides of the discharge head, a light shielding plate provided in the light source and positioned between the discharge head and the light source, and a wiper that wipes the discharge head with a wiper. A printing device is disclosed that includes an ink absorber that receives ink. In the printing apparatus of Patent Document 2, the light source is located at a position higher than the ejection surface of the ejection head.

Japanese Patent Application Publication No. 2018-024132 JP2012-086581A

However, in the printing device of Patent Document 1, when the distance between the ejection head and the light source and the printing medium becomes large, reflected light is irradiated onto the nozzle, resulting in non-ejection due to hardening of ink in the nozzle. Things were happening. Further, in the printing device of Patent Document 2, since a light shielding plate is provided at the light source, it is difficult to sufficiently reduce the irradiation of reflected light to the nozzle, similarly to the printing device of Patent Document 1.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printing apparatus that can reduce the possibility of ink failure due to irradiation with reflected light while increasing the efficiency of using light from a light source.

The printing apparatus according to the present invention includes: a platen that supports a printing medium; an ejection head that moves in a movement direction and ejects ultraviolet curing ink onto the printing medium; a light source disposed at a different position from the ejection head and irradiating light for curing the ultraviolet curable ink; the ejection head is provided on a side surface disposed on the light source side; The ejection head has a reflecting plate extending downward from the bottom of the light source, and the bottom of the light source is arranged at a higher position with respect to the platen than the bottom of the ejection head.

According to the present invention, a reflection plate is provided on the side surface of the ejection head, so that part of the incident light emitted from the light source is reflected by the reflection plate without being irradiated onto the ejection head. This makes it possible to reduce the amount of reflected light irradiating the ejection head compared to the conventional method. Further, a part of the light reflected by the reflection plate is irradiated onto the printing medium. Thereby, the ink can be sufficiently cured while increasing the efficiency of using light from the light source. Further, the lowest part of the light source is arranged at a higher position with respect to the platen than the lowest part of the ejection head. As a result, when for example, when ink such as clear ink is irradiated with light to cure ink such as clear ink in the outward and return passes (that is, 2-scan curing), the amount of light irradiation can be suppressed during the outward pass, and therefore the semi-cured area within the ink can be widely formed. As a result, it is possible to suppress the formation of a cured area of ink and an uncured area of ink, thereby suppressing the appearance of streaks at the boundary line between the cured area and the uncured area. I can do it.

According to the present invention, it is possible to provide a printing device that can reduce the possibility of ink failure due to irradiation with reflected light while increasing the efficiency of using light from a light source.

1 is a perspective view showing a printing device provided with a droplet ejection device according to an embodiment of the present invention. FIG. 1 is a plan view showing a droplet ejection device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the ejection head in FIG. 1. FIG. FIG. 2 is a diagram showing a light emitting diode chip in a light source. FIG. 2 is a block diagram showing the components of the printing device of FIG. 1. FIG. FIG. 3 is a diagram for explaining an example of the positional relationship between a light emitting diode chip and a proximal nozzle array of an ejection head provided with a reflection plate. 7 is a diagram illustrating a modification of the reflector of FIG. 6. FIG.

Hereinafter, a printing apparatus according to an embodiment of the present invention will be described with reference to the drawings. The printing device described below is only one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiments, and additions, deletions, and changes can be made without departing from the spirit of the present invention.

FIG. 1 is a perspective view showing a printing apparatus 1 according to an embodiment of the present invention. In FIG. 1, mutually orthogonal directions are defined as a first direction Ds, a second direction Df, and a third direction Dz. In this embodiment, for example, the first direction Ds is the moving direction of the carriage 3, which will be described later, the second direction Df is the transport direction of the printing medium W, which will be described later, and the third direction Dz is the vertical direction. In the following description, Ds will be referred to as a moving direction, Df will be referred to as a transport direction, and Dz will be referred to as an up-down direction.

As shown in FIG. 1, the printing apparatus 1 of the present embodiment includes a housing 2, an operation key 4, a display section 5, a platen 6 on which a printing medium W is placed, an upper cover 7, and an ejection head. 10 and a light source 40 (FIG. 2), and a controller unit 19 (FIG. 5) including a control device 20 (FIG. 5). The ejection head 10 is, for example, an inkjet head that ejects ultraviolet curing ink droplets.

The housing 2 is formed into a box shape. The housing 2 has an opening 2a. The housing 2 is provided with operation keys 4. Further, a display section 5 is provided near the operation keys 4. The operation keys 4 accept operation inputs from the user. The display unit 5 is composed of, for example, a touch panel, and displays predetermined information. A part of the display section 5 also functions as an operation key. The controller unit 19 implements a printing function based on input from the operation keys 4 or external input via a communication interface (not shown), and also controls the display on the display unit 5 .

The platen 6 is configured such that a printing medium W can be placed thereon. The platen 6 has a predetermined thickness and is made of, for example, a rectangular plate whose longitudinal direction is the conveyance direction Df. The platen 6 is removably supported by a platen support stand (not shown). The platen support base is configured to be movable in the transport direction Df between a printing position where printing is performed on the printing medium W by driving the transport motor 33 (FIG. 5) and an attachment/detachment position where the printing medium W is removed from the platen 6. be done. As a result, the platen 6 moves the ejection surface of the print medium W relative to the ejection head 10 in the transport direction Df. During printing, the platen 6 moves in the transport direction Df, so the printing medium W placed on the platen 6 is transported along the transport direction Df.

The upper cover 7 is configured to rotate upward when the end thereof is lifted. This exposes the inside of the housing 2.

As shown in FIG. 2, the droplet discharge device 1a includes a storage tank 62, a carriage 3 on which, for example, two discharge heads 10 (10A, 10B) and two light sources 40 (40A, 40B) are mounted, and a pair of A guide rail 67 is provided. The ejection head 10 has a plurality of nozzle rows NL that are arranged in parallel in the moving direction Ds and include a proximal nozzle row KNL (FIG. 6) closest to the light source 40. Note that although two ejection heads 10 and two light sources 40 are provided, the present invention is not limited to this, and one ejection head 10 and one light source 40 may be provided.

The carriage 3 is supported by a pair of guide rails 67 extending in the moving direction Ds, and reciprocates in the moving direction Ds along the guide rails 67. Thereby, the two ejection heads 10 (10A, 10B) and the two light sources 40 (40A, 40B) can reciprocate in the moving direction Ds. Further, the discharge head 10 is connected to a storage tank 62 via a tube 62a.

In this embodiment, for example, the ejection head 10A ejects ink droplets of yellow (Y), magenta (M), cyan (C), and black (K), which are sometimes collectively referred to as color ink. A color image is printed on the printing medium W by ejecting the ink droplets of the above four colors onto the printing medium W. On the other hand, the ejection head 10B ejects white (W) ink droplets and clear (Cr) ink droplets. For example, when printing a color image on fabric as the printing medium W, ink droplets of white ink are first ejected as base ink to reduce the effect on the color of the fabric and the material of the fabric. Color ink droplets are ejected onto the ink droplets. Further, ink droplets of clear ink are ejected when adding gloss or protecting a printed area.

Ink is stored in the storage tank 62. A storage tank 62 is provided for each type of ink. For example, six storage tanks 62 are provided, and each of the storage tanks 62 stores black, yellow, cyan, magenta, white, and clear ink.

The droplet discharge device 1a further includes a purge section 50 and a wipe section 54. The purge section 50 and the wipe section 54 are arranged on one end side of the pair of guide rails 67 in the moving direction Ds so as to overlap with the moving area of the carriage 3.

The purge section 50 has a cap 51, a suction pump 52, and a lifting mechanism 53. A suction pump 52 is connected to the cap 51. The lifting mechanism 53 lifts and lowers the cap 51 between the suction position and the standby position. In the standby position, the discharge surface NM (FIG. 3) is separated from the cap 51. On the other hand, at the suction position, the discharge surface NM is covered by the cap 51, forming a sealed space. When the suction pump 52 is driven while the cap 51 is in the suction position, the sealed space is suctioned, and a purge process is performed in which ink is discharged from the nozzle hole 121a (FIG. 3), which will be described later.

Further, the wipe section 54 includes two wipers 55 and 56 and a moving mechanism 57. The two wipers 55 and 56 are supported by a moving mechanism 57. The moving mechanism 57 moves in the transport direction Df with the discharge surface NM disposed at a position facing these wipers 55 and 56. As a result, the two wipers 55 and 56 perform a wiping operation (that is, wipe the discharge surface NM) while moving in the transport direction Df.

Next, the detailed structure of the ejection head 10 will be explained. As shown in FIG. 3, the ejection head 10 has a plurality of nozzles 121 that eject ink droplets using ink from the storage tank 62. The ejection head 10 has a stacked body of a flow path forming body and a volume changing part. An ink flow path is formed inside the flow path forming body, and a plurality of nozzle holes 121a are opened on the ejection surface NM, which is the lower surface. Further, the volume changing section described above is driven to change the volume of the ink flow path. At this time, the meniscus in the nozzle hole 121a vibrates and ink is ejected.

The above-mentioned flow path forming body of the ejection head 10 is a stacked body of a plurality of plates, and the volume changing section includes a diaphragm 155 and an actuator (piezoelectric element) 160. A common electrode 161, which will be described later, is connected to the top of the diaphragm 155.

The plurality of plates are, in order from the bottom, a nozzle plate 146, a spacer plate 147, a first flow path plate 148, a second flow path plate 149, a third flow path plate 150, a fourth flow path plate 151, and a fifth flow path plate. 152, a sixth flow path plate 153, and a seventh flow path plate 154.

Each plate has holes and grooves of various sizes formed therein. Inside the channel forming body in which the plates are laminated, holes and grooves are combined to form a plurality of nozzles 121, a plurality of individual channels 164, and a manifold 122 as ink channels.

The nozzle 121 is formed to penetrate the nozzle plate 146 in the stacking direction. On the ejection surface NM of the nozzle plate 146, a plurality of nozzle holes 121a, which are the tips of the nozzles 121, are lined up in the transport direction Df to form a nozzle row NL.

The manifold 122 supplies ink to a pressure chamber 128 to which ejection pressure is applied. The manifold 122 extends in the transport direction Df, and is connected to one end of each of the plurality of individual channels 164. That is, the manifold 122 functions as a common flow path for ink. The manifold 122 is formed by through holes penetrating the first to fourth flow path plates 148 to 151 in the stacking direction and depressions depressed from the lower surface of the fifth flow path plate 152, overlapping in the stacking direction.

Nozzle plate 146 is arranged below spacer plate 147. The spacer plate 147 is made of stainless steel, for example. The spacer plate 147 has a recess 145 that is recessed from the surface on the nozzle plate 146 side in the thickness direction of the spacer plate 147 by, for example, half etching, thereby forming a thin portion forming a damper portion 147a and a damper space 147b. As a result, a damper space 147b serving as a buffer space is formed between the manifold 122 and the nozzle plate 146.

A supply port 122a communicates with the manifold 122. The supply port 122a is formed into a cylindrical shape, for example, and is provided at one end in the conveyance direction Df. Note that the manifold 122 and the supply port 122a are connected through a flow path (not shown).

Each individual flow path 164 is connected to the manifold 122, respectively. The individual flow path 164 has an upstream end connected to the manifold 122 and a downstream end connected to the base end of the nozzle 121. The individual flow path 164 is composed of a first communication hole 125, a supply restriction path 126 which is an individual restriction path, a second communication hole 127, a pressure chamber 128, and a descender 129, and these components are arranged in this order. be done.

The first communication hole 125 has its lower end connected to the upper end of the manifold 122, extends upward from the manifold 122 in the stacking direction, and penetrates the upper portion of the fifth channel plate 152 in the stacking direction.

The upstream end of the supply throttle passage 126 is connected to the upper end of the first communication hole 125. The supply restricting passage 126 is formed by, for example, half etching, and is constituted by a groove recessed from the lower surface of the sixth flow passage plate 153. The second communication hole 127 has an upstream end connected to the downstream end of the supply constriction path 126, extends upward from the supply constriction path 126 in the stacking direction, and is formed by penetrating the sixth flow path plate 153 in the stacking direction. has been done.

The pressure chamber 128 has its upstream end connected to the downstream end of the second communication hole 127 . The pressure chamber 128 is formed to penetrate the seventh passage plate 154 in the stacking direction.

The descender 129 includes a spacer plate 147, a first passage plate 148, a second passage plate 149, a third passage plate 150, a fourth passage plate 151, a fifth passage plate 152, and a sixth passage plate 153. It is formed to penetrate in the stacking direction. The descender 129 has its upstream end connected to the downstream end of the pressure chamber 128 and its downstream end connected to the base end of the nozzle 121. For example, the nozzle 121 overlaps the descender 129 in the stacking direction and is arranged at the center of the descender 129 in the width direction.

The diaphragm 155 is stacked on the seventh flow path plate 154 and covers the upper end opening of the pressure chamber 128.

Actuator 160 includes a common electrode 161, a piezoelectric layer 162, and individual electrodes 163, which are arranged in this order. The common electrode 161 covers the entire surface of the diaphragm 155. The piezoelectric layer 162 covers the entire surface of the common electrode 161. An individual electrode 163 is provided for each pressure chamber 128 and arranged on the piezoelectric layer 162. One actuator 160 is constituted by one individual electrode 163, one common electrode 161, and a piezoelectric layer 162 sandwiched between the two electrodes.

Individual electrodes 163 are electrically connected to the driver IC. This driver IC receives a control signal from the control device 20, generates a drive signal (voltage signal), and applies it to the individual electrodes 163. In contrast, the common electrode 161 is always held at the ground potential. In such a configuration, the active portion of the piezoelectric layer 162 expands and contracts in the plane direction together with the common electrode 161 and the individual electrodes 163 in response to a drive signal. In response to this, the diaphragm 155 cooperates to deform, changing in a direction that increases or decreases the volume of the pressure chamber 128. As a result, the ejection pressure that causes ink droplets to be ejected from the nozzle 121 is applied to the pressure chamber 128 .

In the ejection head 10, when ink flows into the manifold 122 via the supply port 122a, it flows from the manifold 122 into the supply constriction path 126 via the first communication hole 125, and from the supply constriction path 126 to the second communication hole 127. Flows into the pressure chamber 128 via. The ink then flows through descender 129 and into nozzle 121. Here, when ejection pressure is applied to the pressure chamber 128 by the actuator 160, ink droplets are ejected from the nozzle hole 121a.

FIG. 4 is a diagram showing a light emitting diode chip DT in the light source 40. As shown in FIG. 4, the light source 40 includes a support substrate 41 and a plurality of light emitting diode chips DT arranged on the support substrate 41 and emitting ultraviolet rays. Each light emitting diode chip DT irradiates ultraviolet rays for curing the ink ejected by the ejection head 10. The light emitting diode chip DT is a semiconductor element that generates ultraviolet light. The light emitting diode chips DT are regularly arranged, for example, at predetermined intervals in the movement direction Ds and the conveyance direction Df, respectively. The light emitting diode chips DT are arranged, for example, in a matrix.

Next, each component of the printing apparatus 1 of this embodiment will be explained with reference to a block diagram. FIG. 5 is a block diagram showing the components of the printing apparatus 1 of FIG. 1. As shown in FIG.

As shown in FIG. 5, the printing apparatus 1 includes, in addition to the above-mentioned components, a controller unit 19, a reading device 26, motor driver ICs 30 and 31, head driver ICs 32 and 35, a conveyance motor 33, a carriage motor 34, and an irradiation device driver. It includes ICs 36 and 37, a purge driver IC 38, and a wipe driver IC 39.

The controller unit 19 includes a control device 20 including a CPU, a storage section (ROM 21, RAM 22, EEPROM 23, HDD 24), and ASIC 25. The control device 20 is connected to each of the above-mentioned storage sections and controls each of the driver ICs 30 to 32, 35 to 39 and the display section 5.

The control device 20 executes various functions by executing predetermined processing programs stored in the ROM 21. The control device 20 may be implemented in the controller unit 19 as one processor, or may be implemented as a plurality of processors that cooperate with each other. The processing program is read by the reading device 26 from a recording medium KB such as a computer-readable magneto-optical disk or a USB flash memory, and is stored in the ROM 21 . The RAM 22 stores image data received from the outside, calculation results of the control device 20, and the like. The EEPROM 23 stores various kinds of initial setting information input by the user. Specific information and the like are stored in the HDD 24.

Motor driver ICs 30 and 31, head driver ICs 32 and 35, irradiation device driver ICs 36 and 37, purge driver IC 38, wipe driver IC 39, and 3D camera 58 are connected to ASIC 25. When the control device 20 receives a print job from a user, it outputs an image recording command to the ASIC 25 based on the processing program. The ASIC 25 drives each driver IC 30 to 32 and 35 to 39 based on the image recording command. The control device 20 moves the platen 6 in the transport direction Df by driving the transport motor 33 using the motor driver IC 30. The control device 20 moves the carriage 3 in the movement direction Ds by driving the carriage motor 34 with the motor driver IC 31.

The control device 20 converts image data acquired from an external device or the like into ejection data for ejecting ink droplets onto a surface to be ejected. The control device 20 causes the head driver ICs 32 and 35 to eject ink droplets from the ejection head 10 based on the converted ejection data. Further, the control device 20 causes the irradiation device driver ICs 36 and 37 to irradiate ultraviolet rays from the light emitting diode chips of the light sources 40A and 40B. The control device 20 drives the suction pump 52 and the lifting mechanism 53 of the purge section 50 using the purge driver IC 38. The control device 20 drives the moving mechanism 57 of the wipe section 54 using the wipe driver IC 39 .

FIG. 6 is a diagram for explaining an example of the positional relationship between the adjacent nozzle row KNL of the ejection head 10A provided with the reflection plate 70 and the light emitting diode chip DT. Although the reflecting plate 70 is provided in the ejection head 10A and the ejection head 10B, the ejection head 10A will be described below as a representative example.

As shown in FIG. 6, the ejection head 10A has a side surface 10m located on the light source 40A side. Further, the ejection head 10A has a reflection plate 70 provided on the side surface 10m. The reflecting plate 70 extends below the lowest portion of the light emitting diode chip DT of the light source 40 . The lowest part of the light emitting diode chip DT is arranged at a higher position with respect to the platen 6 than the lowest part of the ejection head 10A (that is, the ejection surface NM).

In FIG. 6, the horizontal distance between the adjacent nozzle row KNL of the ejection head 10A and the center of the light emitting diode chip DT closest to the adjacent nozzle row KNL is defined as L1. Let H be the distance in the vertical direction Dz between the ejection surface NM of the ejection head 10A and the platen 6, and let h be the distance in the vertical direction Dz between the lowest part of the light emitting diode chip DT and the ejection surface NM of the ejection head 10A. Also, the distance between the reflection point Rp on the platen 6 in the moving direction Ds of the incident light IL having 70% of the maximum illuminance among the incident lights emitted from the light emitting diode chip DT and the center of the light emitting diode chip DT in the moving direction Ds. Let be L2. The distance between the reflection point Rp and the adjacent nozzle row KNL in the moving direction Ds is defined as L3. Furthermore, the angle of incidence of the incident light IL (the acute angle formed by the incident light IL and the platen 6) is set to α1, and the reflection angle of the reflected light RL (the acute angle formed between the reflected light RL and the platen 6) is set to α2. Note that the reflection angle α2 is basically the same as the incidence angle α1.

When L2+L3≧L1 is satisfied, in other words, when {(H+h)/tanα1}+(H/tanα2)≧L1 is satisfied, the reflected light RL is irradiated onto the adjacent nozzle row KNL. In this case, regarding the incident angle α1, the first calculation formula, α1=atan{(H+h)/L2}, holds true. Regarding the reflection angle α2, the second calculation formula, α2=atan(H/L3), holds true.

Here, considering that the maximum illuminance is reduced by about 30% when the reflection angle α2 becomes less than 60°, the reflected light RL whose reflection angle α2 is 60° or more (the illuminance is 70% or more of the maximum illuminance) The distance h between the lowest part of the light emitting diode chip DT and the ejection surface NM of the ejection head 10A is defined so that the reflected light RL) is not irradiated onto the adjacent nozzle row KNL.

As described above, since the reflection angle α2 is the same as the incidence angle α1, α2=atan {(H+h)/L2} holds true. Therefore, when α1=α2=60°, since h/(L2-L3)=1.73, h=1.73×(L2-L3) is derived. Therefore, when h≧1.73×(L2−L3) is satisfied, it is possible to prevent the adjacent nozzle row KNL from being irradiated with the reflected light RL whose illuminance is 70% or more of the maximum illuminance. Note that based on (H+h)/L2=1.73, it is also possible to determine the distance h so that h≧1.73×L2−H is satisfied.

Further, in FIG. 6, the horizontal distance between the reflector 70 and the center of the light emitting diode chip DT is L4, and the angle of the incident light IL with respect to the vertical line passing through the center of the light emitting diode chip DT is α3. At this time, the light emitted from the light emitting diode chip DT can be reflected by the reflecting plate 70 when 90°-atan(L4/h)≦α3 is satisfied. From the above calculation formula, h≦L4/tanα3 is derived. In this case, if the incident light IL for which α3 is, for example, 45 degrees or more is reflected by the reflection plate 70, the lowest part of the light emitting diode chip DT and the ejection surface NM of the ejection head 10A are connected so that h≦L4 is satisfied. It is sufficient to specify the distance h.

A reflector 71 in FIG. 7 may be used instead of the reflector 70 in FIG. 6. As shown in FIG. 7, the reflecting plate 71 includes a reflecting surface 71a that faces the light emitting diode chip DT side and has an upper end 71t and a lower end 71l. This reflective surface 71a is inclined so that the horizontal distance Dh1 between the upper end 71t and the center of the light emitting diode chip DT (the center in the moving direction Ds) is smaller than the horizontal distance Dh2 between the lower end 71l and the center of the light emitting diode chip DT. ing.

As described above, according to the printing apparatus 1 of the present embodiment, by providing the reflection plate 70 on the side surface 10m of the ejection head 10, part of the incident light IL emitted from the light emitting diode chip DT is The light is reflected by the reflection plate 70 without being irradiated onto the ejection head 10. This makes it possible to reduce the amount of reflected light RL irradiated onto the nozzle 121 compared to the conventional method. Further, a part of the light reflected by the reflection plate 70 is irradiated onto the printing medium W. Thereby, the ink can be sufficiently cured while increasing the efficiency of using light from the light emitting diode chip DT.

Further, in the present embodiment, the lowest portion of the light source 40 is arranged at a position higher than the ejection surface NM of the ejection head 10 with respect to the platen 6. As a result, when for example, when ink such as clear ink is irradiated with light to cure ink such as clear ink in the outward and return passes (that is, 2-scan curing), the amount of light irradiation can be suppressed during the outward pass, and therefore the semi-cured area within the ink can be widely formed. As a result, it is possible to suppress the formation of a cured area of ink and an uncured area of ink, thereby suppressing the appearance of streaks at the boundary line between the cured area and the uncured area. I can do it.

In the present embodiment, the reflective surface 71a of the reflective plate 70 is inclined so that the horizontal distance Dh1 between the upper end 71t and the light emitting diode chip DT is smaller than the horizontal distance Dh2 between the lower end 71l and the light emitting diode chip DT. There is. Thereby, the printing medium W can be sufficiently irradiated with the light reflected by the reflection plate 70. Thereby, the ink can be sufficiently cured while further improving the efficiency of using light from the light emitting diode chip DT.

Furthermore, in this embodiment, the distance h between the lowest part of the light emitting diode chip DT and the ejection surface NM of the ejection head 10A is defined so that the reflected light RL with a reflection angle α2 of 60° or more is not irradiated onto the adjacent nozzle row KNL. be done. Thereby, it is possible to suppress or prevent the reflected light RL whose illuminance is 70% or more of the maximum illuminance from being irradiated onto the nozzles 121 of the ejection head 10 .

(Modified example)
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example:

In the embodiment described above, the lowermost surface of the reflector 70 and the ejection surface NM of the ejection head 10A are flush with each other, but the lowermost surface of the reflector 70 is located at a lower position in the vertical direction Dz than the lowermost portion of the light emitting diode chip DT. For example, it may be placed at a position lower than the ejection surface NM.

Further, in the above embodiment, the entire surface of the reflective surface 71a is formed to be inclined, but the present invention is not limited to this, and only a portion of the reflective surface 71 may be inclined.

Furthermore, in the above embodiment, the distance h between the lowest part of the light emitting diode chip DT and the ejection surface NM of the ejection head 10A is set so that the reflected light RL whose illuminance is 70% or more of the maximum illuminance is not irradiated onto the adjacent nozzle row KNL. stipulated. However, the present invention is not limited to this, and the distance h may be defined so that the reflected light RL whose illuminance is less than 70% (for example, 60% or more and less than 70%) of the maximum illuminance is not irradiated onto the adjacent nozzle row KNL.

1 Printing device 6 Platen 10, 10A, 10B Discharge head 10m Side surface 40, 40A, 40B Light source 70, 71 Reflector plate 71a Reflective surface 71l Lower end 71t Upper end 121 Nozzle Dh1, Dh2 Horizontal distance Ds Moving direction DT Light emitting diode chip IR Incident light KNL Proximity nozzle row NL Nozzle row RL Reflected light Rp Reflection point W Printing medium

Claims (3)

a platen that supports a print medium;
an ejection head that moves in the movement direction and ejects ultraviolet curable ink onto the printing medium;
a light source that moves in the movement direction, is disposed at a position different from the ejection head in the movement direction, and irradiates light that cures the ultraviolet curable ink;
The ejection head has a side surface disposed on the light source side, and a reflection plate provided on the side surface and extending below the lowest part of the light source,
In the printing device, a lowermost portion of the light source is disposed at a higher position than a lowermost portion of the ejection head with respect to the platen. The reflective plate includes a reflective surface facing the light source and having an upper end and a lower end,
The printing device according to claim 1, wherein the reflective surface is inclined such that a horizontal distance between the upper end and the light source is smaller than a horizontal distance between the lower end and the light source. The ejection head has a plurality of nozzle rows that are arranged in parallel in the movement direction and include a proximate nozzle row that is closest to the light source,
The distance between the reflection point on the platen in the movement direction of light having 70% of the maximum illumination out of the light emitted from the light source and the center of the light source in the movement direction is L2, and the distance between the reflection point and the proximal nozzle is L2. When the distance from the column in the moving direction is L3, and the distance between the lowest part of the light source and the lowest part of the ejection head in the direction intersecting the moving direction,
The printing device according to claim 1, wherein the distance h satisfies h≧1.73×(L2−L3).

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