JP7175131B2 - printer - Google Patents

Description

The present invention relates to printing devices.

An inkjet printer is known as an example of a printing device. Patent Literatures 1 and 2 describe inkjet printers (so-called UV printers) that eject UV-curable ink onto a medium and irradiate dots formed on the medium with UV rays to cure the dots.

Japanese Patent No. 5041611 Patent No. 2015-63057

In such a UV printer, a pass in which ink is ejected while moving the head in the scanning direction to form dots while irradiating light from the irradiation unit, and a transport operation in which the transport unit transports the medium in the transport direction are alternately performed. is performed on In order to form smooth dots, it is necessary to irradiate the dots with light after a predetermined period of time has passed after the dots are formed. For this reason, by turning on the irradiating section arranged on the downstream side of the head in the transport direction, the time from the dot formation to the light irradiation may be ensured. In this way, when the dots are cured by the irradiation unit arranged downstream of the head in the transport direction, due to the structure, even after all the dots are formed, some of the dots still emit light with sufficient energy. It is not irradiated and is in a state of insufficient curing. Therefore, it is necessary to irradiate the insufficiently cured dots with light even after all the dots are formed on the medium. However, if the medium is transported in the transport direction in order to irradiate the insufficiently cured dots with light, a space is required to feed the medium downstream in the transport direction (see later reference examples in FIGS. 14A to 14C). .

SUMMARY OF THE INVENTION It is an object of the present invention to realize, in a space-saving manner, irradiation of light on dots that are insufficiently cured after all dots are formed.

The main invention for achieving the above object is to provide a transport unit for transporting a medium in the transport direction, a head having a nozzle row in which a plurality of nozzles are arranged in the transport direction and movable in the scanning direction, and and an irradiating unit that irradiates light onto a region that is long in the transport direction, and that is movable in the scanning direction together with the head, and an irradiating unit that moves the head in the scanning direction and ejects ink from the nozzles while moving the head in the scanning direction. a control unit for alternately performing a pass for irradiating the light from the irradiation unit and a transport operation for transporting the medium in a transport direction by the transport unit, wherein the control unit causes the irradiation unit to irradiate the print area; and a non-printing area irradiating section adjacent to the downstream side of the printing area irradiating section in the transport direction, and lighting and extinguishing of each can be controlled. The non-printing area irradiation unit is arranged downstream in the transport direction from the downstream end of the nozzle row in the transport direction, and the control unit controls the head to move in the scanning direction. By alternately performing the pass in which the non-printing area irradiation unit is turned on to irradiate the light while ejecting ink from the nozzles while moving to the medium, and the conveying operation, all the parts to be formed on the medium are alternately performed. after forming the dots, while maintaining the relative position in the transport direction between the recording medium and the head, upstream in the transport direction from the area in which the non-printing area irradiation unit was turned on in the previous pass. A pass is performed in which the light is emitted from the irradiation unit without ejecting ink from the nozzles while the head is moved in the scanning direction in a state where the lighting region is changed to include the region on the side. It is a printing device that

Other features of the present invention will become apparent from the description of this specification.

According to the present invention, it is possible to irradiate the insufficiently cured dots with light in a space-saving manner after all the dots are formed.

FIG. 1 is a schematic explanatory diagram of a printing system 100 according to this embodiment. FIG. 2 is a block diagram of the printing system 100. As shown in FIG. FIG. 3A is a schematic explanatory diagram of the transport section 30 and the irradiation section 50. FIG. FIG. 3B is an explanatory diagram of the arrangement of the nozzle rows 44 of the head 41 and the irradiation section 50. As shown in FIG. 4A to 4F are explanatory diagrams of how dots are formed. FIG. 5A is an explanatory diagram showing another method of dot formation in FIGS. 4A to 4F. FIG. 5B is an explanatory diagram of multi-pass printing. FIG. 6 is an explanatory diagram of four-pass printing using half of the nozzle array 44 . FIG. 7A is an explanatory diagram of how dots are formed in the n-th (n>4) pass when four-pass printing is performed using all nozzles. FIG. 7B is an explanatory diagram of how dots are formed in the n-th pass (n>4) when 4-pass printing is performed using half of the nozzle row 44 . FIG. 8 is a graph of the irradiation intensity of the irradiation unit 50. As shown in FIG. FIG. 9 is a diagram showing the positional relationship between the nozzle row 44 and the irradiation section 50. As shown in FIG. FIG. 10A is an explanatory diagram of how dots are formed in the color print mode. FIG. 10B is an explanatory diagram of how dots are formed in the gloss print mode. FIG. 11 is an explanatory diagram of how dots are formed in the glossy color print mode. FIG. 12 is an explanatory diagram of how dots are formed during smooth color printing. FIG. 13 is an explanatory diagram of how dots are formed in the primer print mode. 14A to 14C are explanatory diagrams of the termination process of the reference example. 15A to 15C are explanatory diagrams of termination processing in this embodiment. 16A to 16C are explanatory diagrams of the termination process of the modified example. FIG. 17 is an explanatory diagram of the configuration of the second embodiment. FIG. 18 is an explanatory diagram of the arrangement of the nozzle rows and the irradiation unit 50 according to the third embodiment. FIG. 19 is a diagram showing the positional relationship between the nozzle rows and the irradiation section 50. As shown in FIG. FIG. 20A is an explanatory diagram of how dots are formed in the color print mode of the third embodiment. FIG. 20B is an explanatory diagram of how dots are formed in the special print mode according to the third embodiment. 21A to 21C are explanatory diagrams of termination processing of the third embodiment.

===First embodiment===
<Basic Configuration of Printing System 100>
FIG. 1 is a schematic explanatory diagram of a printing system 100 according to this embodiment. FIG. 2 is a block diagram of the printing system 100. As shown in FIG.

In the following description, the moving direction of the carriage 21 may be called "scanning direction" or "horizontal direction". Also, the moving direction of the medium M is referred to as the "conveying direction", the supply side of the medium M is referred to as "upstream (upstream side)", and the ejection side of the medium M after printing is referred to as "downstream (downstream side)". There is

The printing system 100 is a system for ejecting ink droplets onto a medium M for printing. The printing system 100 has a printing device 1 and a computer 70 . However, the printing system 100 may be configured as a single printing apparatus by having the printing apparatus 1 implement the functions performed by the computer 70 .

The computer 70 is a print control device for controlling the printing device 1 . The computer 70 generates a command code for controlling the printing device 1 and transmits the command code to the printing device 1 . The printing apparatus 1 that has received the command code from the computer 70 controls each part according to the command code to print on the medium M (described later). The computer 70 is, for example, a general-purpose personal computer 70, in which a print control program (so-called printer driver) is installed. The CPU of the computer 70 functions as a print control section that generates command codes by executing a print control program (so-called printer driver).

The printing device 1 is a device for printing by ejecting ink droplets onto a medium M. As shown in FIG. The printing apparatus 1 of the present embodiment is a UV printer that ejects ultraviolet curable ink (so-called UV ink) onto a medium M, irradiates ultraviolet rays onto dots formed on the medium M, and cures the dots. The printing apparatus 1 of this embodiment includes a carriage section 20 , a transport section 30 , a printing section 40 , an irradiation section 50 and a controller 60 .

The carriage section 20 is a unit for reciprocating the carriage 21 in the scanning direction (horizontal direction). The carriage section 20 has a carriage 21 , a carriage motor 22 and a carriage guide 24 . The carriage 21 is a member that reciprocates in the scanning direction. A head 41 and an irradiation unit 50 are mounted on the carriage 21, and the head 41 and the irradiation unit 50 can be reciprocated in the scanning direction by reciprocating the carriage 21 in the scanning direction. The carriage motor 22 is a drive unit for moving the carriage 21 in the scanning direction. The carriage guide 24 is a member (guide) for guiding the carriage 21 in the scanning direction. The carriage guide 24 is configured as a rail-shaped member along the scanning direction. The controller 60 controls the movement of the carriage 21 by controlling the driving of the carriage motor 22 .

The transport unit 30 is a mechanism for transporting the medium M. As shown in FIG. The medium M to be transported may be a long print medium such as roll paper, or may be cut paper. Further, the medium M is not limited to paper, and may be a medium such as film or cloth.

FIG. 3A is a schematic explanatory diagram of the transport section 30 (and the irradiation section 50). The transport unit 30 has a transport roller 31 and a transport motor 32 . The transport roller 31 is a rotating roller for transporting the medium M on the platen. By rotating the transport roller 31 with the medium M sandwiched between the transport roller 31 and the pinch roller 34, the medium M can be transported in the transport direction. The transport motor 32 is a drive unit for rotating the transport roller 31 . The controller 60 controls the transportation of the medium M by controlling the driving of the transportation motor 32 . Note that the transport unit 30 is not limited to the configuration using the transport rollers 31 . For example, the medium M may be conveyed in the conveying direction by placing the short medium M on a mounting table (flat bed) and moving the mounting table in the conveying direction.

The printing unit 40 is a unit for ejecting ink droplets onto the medium M. As shown in FIG. The printing section 40 has a head 41 and a head driving section 42 . The head 41 has a plurality of nozzle rows 44 (see FIG. 3B) for ejecting ink. The head driving unit 42 is a driving unit that causes each nozzle of the head 41 to eject/non-eject ink droplets. The head drive unit 42 is a drive unit that drives a piezo element if the head 41 is of a piezo type, for example. The head 41 is mounted on the carriage 21 and can move along with the carriage 21 in the scanning direction. The controller 60 controls ejection of ink droplets from the head 41 by controlling the head driving section 42 .

FIG. 3B is an explanatory diagram of the arrangement of the nozzle rows 44 of the head 41 and the irradiation section 50. As shown in FIG.

The head 41 has multiple nozzle rows 44 . A plurality of nozzle rows 44 are arranged side by side in the scanning direction. Each nozzle row 44 is composed of a plurality of nozzles 45 arranged in the transport direction (see the enlarged view of the dotted line area in FIG. 3B). In the following description, the length of the nozzle row 44 in the transport direction is assumed to be L1.

The head 41 has a plurality of color ink nozzle rows for ejecting color ink and a special ink nozzle row for ejecting special ink. The color ink is ink for printing a color image on the medium M, and includes colored ink such as cyan ink, magenta ink, yellow ink, and black ink. The color ink nozzle array includes a cyan ink nozzle array that ejects cyan ink, a magenta ink nozzle array that ejects magenta ink, a yellow ink nozzle array that ejects yellow ink, and a black ink nozzle array that ejects black ink. included. The special ink includes transparent (including translucent) ink such as clear ink, white ink, silver ink, and the like. Clear ink, which is a special ink, includes gloss ink for controlling the glossiness of an image, primer ink (base adjustment ink) for adjusting the base of the medium M, and the like. The special ink nozzle array includes a gloss ink nozzle array, a primer ink nozzle array, and the like.

In this embodiment, the ink ejected from the head 41 is photocurable ink. Photocurable ink is ink that cures when irradiated with light. Here, the photocurable ink is ultraviolet curable ink (UV ink), but may be ink that is cured by being irradiated with light of other wavelengths. The photocurable ink has fluidity before light irradiation, but has a property of curing when a predetermined amount of light is irradiated. When the photo-curing ink is irradiated with light in such an amount that it is not completely cured, the inside is uncured, but the surface is cured. In the following description, the state before being completely cured (the inside is uncured but the surface is cured) may be referred to as "semi-cured" or "semi-cured state".

The irradiation unit 50 is a unit that irradiates light for curing the photocurable ink. In this embodiment, the irradiating section 50 is composed of an LED lamp that irradiates ultraviolet rays. However, the irradiation unit 50 may irradiate light other than ultraviolet light, and may have a configuration other than an LED lamp.

The irradiation unit 50 is configured to be able to irradiate a region longer in the transport direction than the nozzle row 44 with light. The irradiation unit 50 has an LED array 50A, a lens array 50B, and a frame 50C (see FIG. 3A). The LED array 50A is configured by arranging a plurality of LED lamps (light emitting units) in the transport direction. The lens array 50B is configured by arranging lenses in the transport direction. Light emitted from the LED array 50A is applied to the medium M through the lens array 50B. The frame body 50C is a container that houses the LED array 50A and the lens array 50B. The frame 50C also has a function of suppressing leakage of light to the outside of a predetermined area (area facing the irradiation section 50). In the following description, the length of the irradiation unit 50 in the transport direction (the length of the irradiation area (described later) of the irradiation unit 50 in the transport direction) is assumed to be L2. The length L2 of the irradiation unit 50 is more than 1.5 times and less than 2.0 times the length L1 of the nozzle row 44. Specifically, the length L1 of the nozzle row 44 is 1.7 to 2.0. It is set to 1.9 times. A part of the upstream side of the irradiation unit 50 (an upstream irradiation unit 52 and an intermediate irradiation unit 53 to be described later) is arranged so as to be aligned with the nozzle rows 44 in the scanning direction. A part of the downstream side of the irradiation section 50 (a downstream irradiation section 54 to be described later) is arranged so as to protrude further downstream in the transport direction than the downstream end of the nozzle row 44 . The length of the irradiation unit 50 may not be the length of the opening of the lamp, but may be the length of the range (irradiation area) irradiated by the lamp.

The irradiation unit 50 is mounted on the carriage 21 and is movable in the scanning direction together with the carriage 21 (and the head 41). A pair of irradiation units 50 are mounted on the carriage 21, and the pair of irradiation units 50 are arranged on the left and right sides of the head 41 so as to sandwich the head 41 from the scanning direction. The controller 60 can control lighting and extinguishing of the irradiation unit 50 .

The controller 60 is a control unit that controls the printing apparatus 1 . The controller 60 controls the drive units (carriage motor 22, transport motor 32, head drive unit 42, etc.) of the printing apparatus 1 based on command codes from the computer 70. FIG.

<Regarding dot formation>
4A to 4F are explanatory diagrams of how dots are formed. As will be described later, in the present embodiment, light is emitted from the irradiation unit 50 in parallel with dot formation, but first, only dot formation will be described. Also, although the head 41 is provided with a plurality of nozzle rows 44, for the sake of simplification of explanation, dot formation of one nozzle row 44 will be explained here.

As shown in FIGS. 4A and 4B, the controller 60 moves the carriage 21 in the scanning direction, ejects ink from the nozzles while moving the head 41 (nozzle row 44) in the scanning direction, and forms dots on the medium M. Form. In the following description, the operation of moving the carriage 21 in the scanning direction may be called "pass". In FIG. 4B, areas (printing areas) where dots can be formed in one pass are indicated by hatching. The print area is an area where the nozzle rows 44 face each other while the carriage 21 moves across the medium M in the scanning direction.

After moving the carriage 21 in the scanning direction (after forming dots), the controller 60 transports the medium M in the transport direction as shown in FIGS. 4C and 4D. In the following description, this operation may be called "conveyance operation". By the conveying operation, the downstream side of the print area of the previous pass is discharged outside the print area of the next pass (see FIGS. 4E and 4F), and the unprinted area of the medium M is moved upstream of the next print area. will be supplied to the side.

After the transport operation, the controller 60 causes the next pass to occur, as shown in FIGS. 4E and 4F. Thus, the controller 60 forms dots on the medium M by alternately repeating the pass and the transport operation. When the transport length (transport amount) during the transport operation is shorter than the length of the print area in the transport direction, the print area is the print area of the previous pass (see FIG. 4B), as shown in FIG. 4F. Some overlap.

FIG. 5A is an explanatory diagram showing another method of dot formation in FIGS. 4A to 4F. FIG. 5A shows the position (relative position) of the nozzle row 44 for each pass with respect to the medium M. As shown in FIG. As already explained, the head 41 only moves in the scanning direction and does not move in the transport direction. However, as shown in FIG. It is possible to show the state of

FIG. 5B is an explanatory diagram of multi-pass printing. Multi-pass printing is printing in which each region of the medium M is subjected to multiple passes. FIG. 5B shows 4-pass printing in which each area of the medium M is printed four times.

"Area 1" in FIG. 5B is an area printed in one pass (fourth pass). In the case of 4-pass printing, area 1 has about 1/4 of the dots formed. "Area 2" in FIG. 5B is an area printed in two passes (third and fourth passes). In the case of 4-pass printing, approximately half the dots are formed in region 2. "Area 3" in FIG. 5B is an area printed in three passes (second to fourth passes). In the case of 4-pass printing, region 3 has about 3/4 dots. "Area 4" in FIG. 5B is an area printed in four passes (first to fourth passes). In "area 4", the dots formed in each pass (first to fourth passes) are distributed in the transport direction. In this way, multi-pass printing is characterized by being able to disperse the dots formed in each pass in the transport direction. In the case of 4-pass printing, all dots to be formed are formed in area 4 . In the case of 4-pass printing, the transport length (transport amount) during the transport operation is about 1/4 of the length of the print area in the transport direction. Therefore, when ink is ejected from all the nozzles of the nozzle row 44, in the case of 4-pass printing, the transport length (transport amount) during the transport operation is approximately 1/4 of the length L1 of the nozzle row 44. .

FIG. 6 is an explanatory diagram of four-pass printing using half of the nozzle array 44 . In the drawing, portions of the nozzle row 44 that eject ink are hatched. It is assumed that the nozzles in the non-hatched portions are unused, and ink is not ejected from the nozzles in the non-hatched portions.

In this embodiment, each nozzle row 44 is divided into two, an upstream nozzle row 441 and a downstream nozzle row 442, and the controller 60 controls the divided upstream nozzle row 441 and the downstream nozzle row Ejection of each ink of 442 is controllable. The upstream nozzle row 441 is the upstream nozzle row in the transport direction of the nozzle rows 44 divided into two. The downstream nozzle row 442 is a nozzle row on the downstream side in the transport direction of the nozzle rows 44 divided into two, and is a nozzle row on the downstream side in the transport direction of the upstream nozzle row 441 . Since the upstream nozzle row 441 and the downstream nozzle row 442 are adjacent to each other, another nozzle row is not interposed between the upstream nozzle row 441 and the downstream nozzle row 442 .

The upstream nozzle row 441 and the downstream nozzle row 442 are divided substantially evenly. For example, when the nozzle row 44 is composed of 180 nozzles, the upstream nozzle row 441 is composed of 90 nozzles on the upstream side. For example, when the nozzle row 44 is composed of 180 nozzles, the downstream nozzle row 442 is composed of 90 downstream nozzles. In the following description, the length of the upstream nozzle array 441 in the transport direction (or the length of the downstream nozzle array 442 in the transport direction) is assumed to be L11.

As shown in FIG. 6, even when four-pass printing is performed using half of the nozzle rows 44, the transport length (transport amount) during the transport operation is about 1/4 of the length of the print area in the transport direction. becomes. However, since the length of the nozzle row 44 is substantially halved, if ink is ejected from half the nozzles of the nozzle row 44, the transport length (transport amount) during the transport operation in the case of 4-pass printing is It is about ⅛ of the length L 1 of the nozzle row 44 . That is, when performing 4-pass printing using half of the nozzle row 44, the transport length (transport amount) during the transport operation is reduced by about 1 compared to when ink is ejected from all the nozzles of the nozzle row 44. /2.

FIG. 7A is an explanatory diagram of how dots are formed in the n-th (n>4) pass when four-pass printing is performed using all nozzles. FIG. 7B is an explanatory diagram of how dots are formed in the n-th pass (n>4) when 4-pass printing is performed using half of the nozzle row 44 . As shown in the figure, the printing area to be printed in the fourth and subsequent passes is divided into four areas, "area 1", "area 2", "area 3", and "area 4" from the transport direction upstream side. do. Also in this case, "area 1" is an area printed in one pass, and about 1/4 of the dots are formed. Similarly, "area 2" is the area printed in two passes, forming approximately half the dots. "Area 3" is the area printed in three passes, and about 3/4 dots are formed. "Region 4" is a region printed in four passes, and all dots to be formed are formed. Further, on the downstream side of the area 4 in the transport direction, each area after the area 5 is an area printed in four passes, similarly to the "area 4", and all the dots to be formed are formed. The length (width) of each region in the transport direction corresponds to the transport length (transport amount) during the transport operation. In the following description, the multi-pass printing shown in FIGS. 5B and 6 may be explained only by illustrating the state of dot formation in a certain pass as shown in FIGS. 7A and 7B.

<Regarding the irradiation unit 50>
As shown in FIG. 3B, in this embodiment, the irradiation unit 50 is divided into three, an upstream irradiation unit 52, an intermediate irradiation unit 53, and a downstream irradiation unit 54, and the controller 60 is divided into three Lighting and extinguishing of each of the upstream irradiation section 52, the intermediate irradiation section 53, and the downstream irradiation section 54 can be controlled.

The upstream irradiation section 52 is an irradiation section on the upstream side in the conveying direction of the three divided irradiation sections 50 . The upstream irradiation unit 52 is arranged side by side with the upstream nozzle row 441 in the scanning direction. The upstream irradiation section 52 overlaps the range of the upstream nozzle row 441 in the transport direction. Therefore, the upstream irradiation unit 52 can irradiate the dots immediately after being formed by the upstream nozzle row 441 (can irradiate the print area of the upstream nozzle row 441 with light).

The intermediate irradiation section 53 is an irradiation section adjacent to the downstream side of the upstream irradiation section 52 in the transport direction among the irradiation sections 50 divided into three. The intermediate irradiation unit 53 is arranged so as to be aligned with the downstream nozzle row 442 in the scanning direction. The intermediate irradiation unit 53 overlaps the range of the downstream nozzle row 442 in the transport direction, and can irradiate the dots immediately after being formed by the downstream nozzle row 442 with light. Since the intermediate irradiation section 53 is adjacent to the upstream irradiation section 52 , another irradiation section is not interposed between the upstream irradiation section 52 and the intermediate irradiation section 53 .

A combination of the upstream irradiation section 52 and the intermediate irradiation section 53 may be called a print area irradiation section 51 . The print area irradiation section 51 is an irradiation section on the upstream side in the transport direction of the irradiation section 50 . The print area irradiation unit 51 is arranged side by side with the nozzle row 44 in the scanning direction. The print area irradiation unit 51 overlaps the range of the nozzle row 44 in the transport direction. Therefore, the print area irradiation unit 51 can irradiate the dots immediately after being formed by the nozzle row 44 with light.

The downstream irradiation section 54 is an irradiation section adjacent to the downstream side of the intermediate irradiation section 53 in the transport direction among the three irradiation sections 50 . The downstream irradiation section 54 does not overlap the range in the transport direction of the downstream nozzle row 442 and is arranged downstream of the downstream nozzle row 442 in the transport direction. Since the downstream irradiation section 54 is adjacent to the intermediate irradiation section 53 , another irradiation section is not interposed between the downstream irradiation section 54 and the intermediate irradiation section 53 . The downstream irradiation section 54 may be called a non-printing area irradiation section 55 .

The upstream irradiation section 52, the intermediate irradiation section 53, and the downstream irradiation section 54 are divided substantially evenly. In the following description, the length of the upstream irradiation section 52 (or the intermediate irradiation section 53 or the downstream irradiation section 54) in the transport direction is assumed to be L21. In this embodiment, the length L21 of the upstream irradiation section 52 is slightly longer than the length L11 of the upstream nozzle row 441 (half the length L of the nozzle row 44) (L21>L11).

FIG. 8 is a graph of the irradiation intensity of the irradiation unit 50. As shown in FIG. The horizontal axis of the graph indicates the position in the conveying direction. The vertical axis of the graph indicates the irradiation intensity of light per unit area (unit: mW/cm2).

When light is emitted from all regions of the irradiation unit 50, the irradiation intensity reaches the maximum value Pmax in the central portion of the irradiation unit 50, as indicated by the solid line graph. In the figure, P1 is the half value of the maximum value Pmax. Here, the half width is set to correspond to the length of the irradiation section 50 in the transport direction. The position on the upstream side in the transport direction (the position of circle 1 in the graph) where the irradiation intensity is P1 corresponds to the position of the upstream end of the upstream irradiation section 52 . The downstream position in the transport direction where the irradiation intensity is P<b>1 (the position indicated by circle 2 in the graph) corresponds to the position of the downstream end of the downstream irradiation section 54 . P1 has an irradiation intensity capable of curing (including semi-curing) the photocurable ink. Therefore, when light is irradiated from all areas of the irradiation section 50, the area facing the irradiation section 50 is irradiated with light capable of curing (or semi-curing) the photocurable ink. .

In a narrow sense, the irradiation region of the irradiation unit 50 means a region that becomes a predetermined irradiation intensity (here, P1) or more when light is irradiated. In a broad sense, it means a region irradiated with light.

When light is emitted from the entire area of the irradiation unit 50, the change in the irradiation intensity at the position where the irradiation intensity is P1 (slopes at positions circled 1 and circled 2 in the graph) is relatively steep. This is because, as shown in FIG. 3A, the frame 50C of the irradiation section 50 suppresses light from leaking outside the irradiation area (the area facing the irradiation section 50). Therefore, the area where the light leaks to the outside of the irradiation area (the area facing the irradiation unit 50) is very small.

When the downstream irradiation unit 54 is turned off while the print area irradiation unit 51 (the upstream irradiation unit 52 and the intermediate irradiation unit 53) is turned on, the irradiation intensity becomes P1 at the position on the upstream side in the transport direction (marked by circle 1 in the graph). ) corresponds to the position of the upstream end of the upstream irradiation section 52 . The change in irradiation intensity at this position (slope at circle 1 in the graph) is relatively steep. Therefore, the region where light leaks to the upstream side of the upstream irradiation section 52 is very small. The position on the downstream side in the transport direction where the irradiation intensity is P1 (the position of circle 3 in the graph) corresponds to the position of the downstream end of the intermediate irradiation section 53, and the boundary between the intermediate irradiation section 53 and the downstream irradiation section 54. Equivalent to position. The change in irradiation intensity at this position (slope at the position of circle 3 in the graph) is relatively gentle. This is because there is no member such as the frame 50C that blocks light at the boundary between the intermediate irradiation unit 53 and the downstream irradiation unit 54, so the light emitted from the intermediate irradiation unit 53 is This is because the leak also leaks to the downstream side in the conveying direction (the area facing the downstream irradiation section 54). Therefore, the area where the light is irradiated to the downstream side of the intermediate irradiation section 53 is a relatively wide area (the area is wider than the area where the light leaks to the upstream side of the upstream irradiation section 52).

When the print area irradiation unit 51 (the upstream irradiation unit 52 and the intermediate irradiation unit 53) is turned off while the non-printing area irradiation unit 55 (downstream irradiation unit 54) is turned on, the irradiation intensity becomes P1 downstream in the transport direction. The position of the side (the position of circle 2 in the graph) corresponds to the position of the downstream end of the downstream irradiation section 54 . The change in irradiation intensity at this position (the slope at circle 2 in the graph) is relatively steep. Therefore, the area where light leaks to the downstream side of the downstream irradiation section 54 is very small. On the other hand, the position on the upstream side in the transport direction (the position of circle 3 in the graph) where the irradiation intensity is P1 corresponds to the position of the upstream end of the downstream irradiation section 54, and the intermediate irradiation section 53 and the downstream irradiation section 54 Corresponds to the position of the boundary. The change in irradiation intensity at this position (slope at the position of circle 3 in the graph) is relatively gentle. This is because there is no member such as the frame 50C that blocks light at the boundary between the intermediate irradiation section 53 and the downstream irradiation section 54. Therefore, the light emitted from the downstream irradiation section 54 is emitted from the downstream irradiation section This is because the light leaks to the upstream side in the conveying direction (the area facing the intermediate irradiation section 53) of 54 . Therefore, the area where the light is irradiated to the upstream side of the downstream irradiation section 54 becomes a relatively wide area (area wider than the area where the light leaks to the downstream side of the downstream irradiation section 54).

When the intermediate irradiation unit 53 is turned off while the upstream irradiation unit 52 and the downstream irradiation unit 54 are turned on, the irradiation intensity becomes lower than P1 at the central portion of the irradiation unit 50 . Here, the irradiation intensity is set to be lower than P1 in the region facing the intermediate irradiation section 53 . At the position of the upstream end and the position of the downstream end of the intermediate irradiation section 53, the irradiation intensity becomes P1. Changes in irradiation intensity at the upstream end position and the downstream end position of the intermediate irradiation section 53 are relatively gentle. This is because light leaks from the upstream irradiation section 52 and light leaks from the downstream irradiation section 54 .

<Positional Relationship Between Nozzle Row 44 and Irradiation Unit 50>
FIG. 9 is a diagram showing the positional relationship between the nozzle row 44 and the irradiation section 50. As shown in FIG. The positions of the nozzle rows 44 (the upstream nozzle row 441 and the downstream nozzle row 442) are shown on the right side of the drawing. The positions of the irradiation units 50 (the upstream irradiation unit 52, the intermediate irradiation unit 53, and the downstream irradiation unit 54) are shown in the center of the drawing. A graph of the irradiation intensity of the irradiation unit 50 is shown on the left side of the drawing. This graph is similar to that shown in FIG.

The position of the upstream end of the nozzle row 44 (the most upstream nozzle among the plurality of nozzles forming the nozzle row 44 ) is set to the upstream end of the irradiation section 50 . Therefore, the irradiation intensity of the irradiation unit 50 at the position of the upstream end of the nozzle row 44 is set to be P1 (half the maximum value Pmax).

The nozzle row 44 (the upstream nozzle row 441 and the downstream nozzle row 442) is arranged so as to be aligned in the scanning direction with the print region irradiation section 51 (the upstream irradiation section 52 and the downstream irradiation section 54). Since the length of the print region irradiation unit 51 (twice L21) is longer than the length L1 of the nozzle row 44, the print region irradiation unit 51 is arranged so as to cover the range of the nozzle row 44 in the transport direction. ing. When the print area irradiation unit 51 is turned on, the area printed by the nozzle row 44 is irradiated with light exceeding the irradiation intensity P1. That is, when the print area irradiation unit 51 is turned on, the area printed by the nozzle row 44 is irradiated with light capable of curing the photocurable ink.

The upstream nozzle row 441 is arranged so as to line up with the upstream irradiation section 52 in the scanning direction. Since the length L21 of the upstream irradiation section 52 is slightly longer than the length L11 of the upstream nozzle row 441, the upstream irradiation section 52 is arranged so as to cover the range of the upstream nozzle row 441 in the transport direction. ing. When the upstream irradiation unit 52 is turned on, the region printed by the upstream nozzle row 441 is irradiated with light (light exceeding the irradiation intensity P1) capable of curing the photocurable ink. Become.

The downstream nozzle row 442 is arranged so as to be aligned with the intermediate irradiation section 53 in the scanning direction. The position of the upstream end of the downstream nozzle row 442 (the most upstream nozzle among the plurality of nozzles forming the downstream nozzle row 442) is positioned slightly upstream of the position of the upstream end of the intermediate irradiation section 53. . However, the intermediate irradiation section 53 covers most of the range in the transport direction of the downstream nozzle row 442 . When the upstream irradiation section 52 is turned on and the intermediate irradiation section 53 is turned off, most of the area printed by the downstream nozzle row 442 has an irradiation intensity of P1 or less.

In the present embodiment, the position of the downstream end of the nozzle row 44 (the most downstream nozzle among the plurality of nozzles forming the nozzle row 44) is positioned closer to the transport direction than the boundary between the intermediate irradiation section 53 and the downstream irradiation section 54. set upstream. That is, at least a portion of the print region irradiation section 51 on the downstream side in the transport direction (in other words, at least a portion of the intermediate irradiation section 53 on the downstream side in the transport direction) is arranged downstream in the transport direction from the downstream end of the nozzle row 44 . It is Further, the downstream irradiation section 54 is arranged on the downstream side in the transport direction with a gap from the downstream end of the nozzle row 44 . Therefore, when the downstream irradiation unit 54 is turned off while the print area irradiation unit 51 is turned on, the irradiation intensity P2 (see the graph on the left side of FIG. 9) at the downstream end position of the nozzle row 44 is P1 (maximum Pmax half value). Further, when the downstream irradiation unit 54 is turned on while the print region irradiation unit 51 is turned off, the irradiation intensity P3 at the position of the downstream end of the nozzle row 44 becomes a value smaller than P1 (half the maximum value Pmax). . As described above, in the present embodiment, the irradiation intensity P3 at the downstream end of the nozzle row 44 when the downstream side irradiation unit 54 is turned on while the print region irradiation unit 51 is turned off is It is smaller than the irradiation intensity P2 at the same position when the downstream irradiation section 54 is turned off.

<Color print mode and gloss print mode>
FIG. 10A is an explanatory diagram of how dots are formed in the color print mode. Here, the state of 4-pass printing is shown. Although only one color ink nozzle row is shown in the drawing, the other color ink nozzle rows also eject color ink in the same manner as this color ink nozzle row.

In the color print mode, in each pass, the controller 60 causes color ink to be ejected from all nozzles of the color ink nozzle row, and also turns on the print region irradiation section 51 (the upstream irradiation section 52 and the intermediate irradiation section 53). Note that in the color printing mode, since there is no demand for smoothing and it is sufficient to cure the dots, the non-printing area irradiation section 55 (downstream irradiation section 54) may be turned on. Then, the controller 60 alternately performs such a pass and the transport operation. In "Region 1" to "Region 4", color dots are formed on the medium M with color ink, and the color dots immediately after being formed are irradiated with light from the print region irradiation unit 51, and the color dots are cured (or semi-cured). ). In "Region 2" to "Region 4", color dots are formed in the regions where color dots were formed in the previous pass. However, since the color dots formed in the previous pass are cured by being irradiated with light immediately after formation, when further color dots are formed in "area 2" to "area 4", the color dots blur. You can put it in a difficult situation.

In the color print mode of this embodiment, the controller 60 turns on not only the print area irradiation section 51 but also the non-print area irradiation section 55 (downstream side irradiation section 54). As a result, the color dots cured in the "area 4" can be further cured by the light emitted from the non-printing area irradiation section 55 in the "area 5" and beyond. However, as long as the light energy irradiated to the color dots is sufficient, the controller 60 may turn off the non-printing area irradiation section 55 during the color printing mode.

Even if the non-printing area irradiation unit 55 (downstream irradiation unit 54) is turned off, at least a portion of the printing area irradiation unit 51 on the downstream side in the transport direction is transported further than the downstream end of the nozzle row 44 in this embodiment. Since it is arranged downstream in the direction, the irradiation intensity P2 (see the graph on the left side of FIG. 9) at the position of the downstream end of the nozzle row 44 has a value exceeding P1 (half value of the maximum value Pmax). 4” is also irradiated with light of relatively high intensity, and it is possible to cure the color dots.

Further, even if the non-printing area irradiation unit 55 (downstream irradiation unit 54) is turned off, in the present embodiment, the boundary between the intermediate irradiation unit 53 and the downstream irradiation unit 54 is provided with a frame like the frame 50C. Since there is no member that blocks the light, the light emitted from the intermediate irradiation section 53 leaks to the downstream side in the conveying direction from the intermediate irradiation section 53 . For this reason, after all the color dots to be formed are formed, light is emitted from the intermediate irradiation unit 53 also in an area (for example, "area 5") located downstream of "area 4" in the transport direction. It is possible to further harden the color dots by .

FIG. 10B is an explanatory diagram of how dots are formed in the gloss print mode.

In the gloss print mode, the controller 60 causes the gloss ink to be ejected from all the nozzles of the gloss ink nozzle row in each pass, and turns off the print area irradiation unit 51 while turning off the non-print area irradiation unit 55 (downstream irradiation unit 54). ) light up. Then, the controller 60 alternately performs such a pass and the transport operation. In "region 1" to "region 4", gloss dots are formed on the medium M by the gloss ink. In the gloss printing mode, since the print area irradiation unit 51 is turned off, the gloss dots immediately after formation are hardly irradiated with light, and the gloss dots immediately after formation are not cured. As a result, the gloss dots gradually wet and spread on the medium M and are smoothed. In "Region 2" to "Region 4", gloss dots are formed in the regions where gloss dots were formed in the previous pass. However, since the gloss dots formed in the immediately preceding pass are uncured, when further gloss dots are formed in "Region 2" to "Region 4", the uncured gloss inks are mixed and connected. When adjacent dots connect, the surface becomes smooth. As a result, when all the gloss dots to be formed in the "area 4" are formed, a film of gloss ink with a smooth surface (gloss film, gloss layer) is formed. Then, the gloss ink film with a smooth surface is irradiated with light from the non-printing area irradiation unit 55 (downstream irradiation unit 54) in a region (for example, “region 5”) downstream of “region 4” in the transport direction. It will be hardened by being done. Thereby, on the medium M, a glossy layer with a smooth surface can be formed.

In the present embodiment, at least a part of the print region irradiation section 51 on the downstream side in the transport direction is arranged downstream in the transport direction from the downstream end of the nozzle row 44, and the non-print region irradiation section 55 (the downstream irradiation section 54 ) are arranged downstream of the downstream end of the nozzle row 44 in the transport direction. Therefore, the irradiation intensity P3 (see the graph on the left side of FIG. 9) at the position of the downstream end of the nozzle row 44 becomes a value smaller than P1 (half value of the maximum value Pmax). (light leaking from the downstream side irradiation section 54, which is the non-printing area irradiation section 55) is relatively weak. Therefore, the gloss dots formed in the "area 4" are relatively hard to cure. Therefore, since the gloss dots formed in the "region 4" are easily spread and smoothed, a gloss ink film (glossy layer) having a smooth surface can be stably formed.

The light leaked upstream from the non-printing area irradiation unit 55 (downstream irradiation unit 54) is irradiated to the printing areas ("area 3" and "area 4") of the downstream nozzle row 442. (See Figure 9). For this reason, the gloss dots formed in "region 1" to "region 3" are irradiated twice with leaked light from the non-printing region irradiation unit 55 in "region 3" and "region 4". On the other hand, the gloss dots formed in the "area 4" are irradiated once with the leaked light from the non-printing area irradiation unit 55 in the "area 4". In other words, the number of leaked light irradiations from the non-printing area irradiation unit 55 differs between the gloss dots formed in "area 1" to "area 3" and the gloss dots formed in "area 4". . If the difference in the degree of curing of the gloss dots becomes large due to the different number of times of irradiation, a striped pattern may be formed on the film of the gloss ink. However, in the present embodiment, as shown in FIGS. 8 and 9, the non-printing area irradiation unit 55 irradiates the printing area (“area 3” and “area 4”) of the downstream nozzle row 442 with light. Since the intensity is weak, the difference in the degree of curing of the gloss dots due to the difference in the number of times of irradiation is small. In addition, in the present embodiment, as shown in FIGS. 8 and 9, the change in irradiation intensity in the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442 is relatively gradual, and In the present embodiment, since the gloss dots with different irradiation times are dispersed by multi-pass printing, the difference in the degree of hardening of the gloss dots is not noticeable. For this reason, in the present embodiment, the light leaked from the downstream irradiation section 54, which is the non-printing area irradiation section 55, to the upstream side is emitted to the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442. ), formation of a striped pattern on the film of the gloss ink can be suppressed.

<Mixed Print Mode>
In the present embodiment, it is possible to realize a mixed print mode in which dots cured immediately after formation and dots cured after smoothing are mixed and printed. The mixed print mode includes a glossy color print mode, a smooth color print mode, and a primer print mode. In any of the mixed print modes, the controller 60 causes the upstream nozzle array 441 and the downstream nozzle array 442 to eject ink in each pass, while turning on the upstream irradiation section 52 and turning off the intermediate irradiation section 53. , the downstream irradiation unit 54 is turned on. Then, the controller 60 causes such passes and transport operations to be performed alternately. Each print mode will be described below.

Glossy Color Print Mode FIG. 11 is an explanatory diagram of how dots are formed in the glossy color print mode. The glossy color mode is a print mode in which a glossy layer is formed with gloss ink on a color image composed of color dots. Here, a glossy color print mode with 4-pass printing is shown. Since 4-pass printing is performed using half of each nozzle row 44, the transport length (transport amount) during the transport operation is Although it is about 1/2, the reverse conveying operation is not required when printing the glossy layer. On the right side of the drawing, states of dots in areas 2, 4, 6, and 8 are shown.

In the glossy color print mode, in each pass, the controller 60 causes color ink to be ejected from the upstream nozzle row 441 of the color ink nozzle row, and causes gloss ink to be ejected from the downstream nozzle row 442 of the gloss ink nozzle row. The side irradiation unit 52 is turned on, the intermediate irradiation unit 53 is turned off, and the downstream irradiation unit 54 (non-printing area irradiation unit 55) is turned on. Then, the controller 60 causes such passes and transport operations to be performed alternately. In “Region 1” to “Region 4”, color dots are formed on the medium M with color ink, and the color dots immediately after being formed are irradiated with light from the upstream irradiation unit 52, and the color dots are cured (or semi-cured). ). In "Region 2" to "Region 4", color dots are formed in the regions where color dots were formed in the previous pass. However, since the color dots formed in the previous pass are cured by being irradiated with light immediately after formation, when further color dots are formed in "area 2" to "area 4", the color dots blur. You can put it in a difficult situation. That is, it is possible to suppress blurring of a color image composed of color dots.

After all the color dots to be formed have been formed, gloss dots are formed on the medium M with the gloss ink in "area 5" to "area 8". Since the intermediate irradiation unit 53 is turned off, the gloss dots immediately after formation are hardly irradiated with light, and the gloss dots immediately after formation are not cured. Therefore, when gloss dots are formed in "region 5" to "region 8", the uncured gloss ink is connected to form a gloss ink film (glossy film, glossy layer) with a smooth surface. Then, the glossy ink film with a smooth surface is irradiated with light from the downstream side irradiation unit 54 in regions (for example, “region 9” and “region 10”) downstream of “region 8” in the transport direction. will be hardened by Thereby, a glossy layer having a smooth surface can be formed on the color image.

In addition, "area 5" to "area 8" corresponding to the printing area of the downstream nozzle row 442 are irradiated with the light leaked from the upstream irradiation section 52 and the downstream irradiation section 54 (FIG. 8). , see FIG. 9). However, the irradiation intensity in most of this region has a value smaller than P1 (half the maximum value Pmax). For this reason, since most of the gloss dots formed in "Region 5" to "Region 8" are difficult to cure, most of the gloss dots are easily smoothed.

In the present embodiment, at least a part of the print region irradiation section 51 on the downstream side in the transport direction is arranged further downstream in the transport direction than the downstream end of the nozzle row 44 , and the downstream irradiation section 54 is located at the downstream end of the nozzle row 44 . is arranged on the downstream side in the conveying direction. Therefore, the irradiation intensity P3 (see the graph on the left side of FIG. 9) at the position of the downstream end of the nozzle row 44 becomes a value smaller than P1 (half value of the maximum value Pmax). is relatively weak (light leaking from the downstream irradiation section 54). Therefore, the gloss dots formed in the "area 8" are relatively hard to cure. This makes it possible to stably form a glossy ink film (glossy layer) with a smooth surface.

By the way, a partial region on the upstream side of “region 5” is irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 . Therefore, the gloss dots formed in a partial region on the upstream side of “region 5” are irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 immediately after formation. It will be hardened (or semi-hardened). However, given that the area of "area 5" irradiated with light exceeding the irradiation intensity P1 is small, and that gloss dots are formed in this small area by multi-pass printing in a dispersed manner in the transport direction. , Few gloss dots are cured (or semi-cured) immediately after formation. In addition, in "region 6" to "region 8", the gloss dots are formed on the gloss dots cured (or semi-cured) in "region 5". A film of gloss ink with a smooth surface is formed on the (or semi-cured) gloss dots. Therefore, in the present embodiment, the gloss dots formed in a partial area upstream of "area 5" are cured (or semi-cured) immediately after being formed, but the effect of this is slight.

Even in the glossy color print mode, the gloss dots formed in "Region 5" to "Region 8" are irradiated with different numbers of times. However, since the irradiation intensity of the light emitted from the downstream irradiation unit 54 to the printing area ("area 5" to "area 8") of the downstream nozzle row 442 is weak, the degree of curing of the gloss dots varies depending on the number of times of irradiation. The difference is small. In addition, the change in irradiation intensity in the printing region (“region 5” to “region 8”) of the downstream nozzle row 442 is relatively gradual, and the gloss dots with different irradiation times are dispersed by multi-pass printing. Therefore, the difference in the degree of hardening of the gloss dots is inconspicuous. For this reason, even in the glossy color print mode, the light leaked from the downstream irradiation unit 54 to the upstream side is irradiated to the printing area ("area 5" to "area 8") of the downstream nozzle row 442. Also, formation of a striped pattern on the gloss ink film can be suppressed.

-Smooth color printing mode FIG. 12 is an explanatory diagram of how dots are formed during smooth color printing. The smooth color print mode is a print mode that forms color images with a smooth surface. Here, a smooth color print mode with 4-pass printing is shown.

In the smooth color print mode, in each pass, the controller 60 causes color ink to be ejected from the upstream nozzle row 441 and the downstream nozzle row 442 of the color ink nozzle row, and also turns on the upstream irradiation section 52 to turn on the intermediate irradiation section. 53 is turned off, and the downstream irradiation section 54 (non-printing area irradiation section 55) is turned on. Then, the controller 60 causes such passes and transport operations to be performed alternately. In “Region 1” and “Region 2”, color dots are formed on the medium M by color ink ejected from the upstream nozzle row 441, and the color dots immediately after formation are irradiated with light from the upstream irradiation unit 52. , the color dots will be cured (or semi-cured). In "region 2", color dots are formed in the region where color dots were formed in the previous pass. However, since the color dots formed in the immediately preceding pass are cured by being irradiated with light immediately after formation, when further color dots are formed in the 'region 2', the color dots can be made less likely to blur.

In “Region 3” and “Region 4”, color dots are formed on the medium M by the color ink ejected from the downstream nozzle row 442 . Since the intermediate irradiation unit 53 is turned off, the color dots immediately after formation are hardly irradiated with light, and the color dots immediately after formation are not cured. As a result, the color dots formed in "region 3" and "region 4" (color dots formed by the downstream nozzle row 442) gradually spread on the medium M and are smoothed. However, since the color dots formed in "Region 1" and "Region 2" are already cured (or semi-cured), the uncured color ink ejected in "Region 3" and "Region 4" Since it does not mix with the color dots formed in "area 1" and "area 2", bleeding can be suppressed. In addition, since the color dots formed in "region 1" and "region 2" are already cured (or semi-cured), the uncured color ink spreads and spreads smoothly between the already cured color dots. will do. The uncured color inks in “Region 3” and “Region 4” are applied to the downstream side irradiation section 54 (non-printing region irradiation section 55 ), it is cured by being irradiated with light. Thereby, a color image having a smooth surface can be formed on the medium M. FIG.

It should be noted that "area 3" and "area 4" corresponding to the printing area of the downstream nozzle row 442 are irradiated with the light leaked from the upstream irradiation section 52 and the downstream irradiation section 54 (see FIG. 8). , see FIG. 9). However, the irradiation intensity in most of this region has a value smaller than P1 (half the maximum value Pmax). For this reason, most of the color dots formed in "area 3" and "area 4" are in a state of being difficult to cure, and therefore most of the color dots are easily smoothed.

In the present embodiment, at least a part of the print region irradiation section 51 on the downstream side in the transport direction is arranged further downstream in the transport direction than the downstream end of the nozzle row 44 , and the downstream irradiation section 54 is located at the downstream end of the nozzle row 44 . is arranged on the downstream side in the conveying direction. Therefore, the irradiation intensity P3 (see the graph on the left side of FIG. 9) at the position of the downstream end of the nozzle row 44 becomes a value smaller than P1 (half value of the maximum value Pmax). (light leaking from the downstream irradiation unit 54) is relatively weak. Therefore, the color dots formed in "region 4" are relatively hard to cure. As a result, color ink having a smooth surface can be stably formed.

By the way, a partial region on the upstream side of “region 3” is irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 . Therefore, the color dots formed in a partial region on the upstream side of “region 3” are irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 immediately after formation. It will be hardened (or semi-hardened). However, in the smooth color print mode, the ink ejected from the upstream nozzle row 441 and the ink ejected from the downstream nozzle row 442 are the same. The color dots that cure immediately after) are almost indistinguishable from the color dots formed in "Region 2". Therefore, even if the color dots in a part of the upstream area of "area 3" are cured immediately after being formed, there is no effect on the image quality of the color image.

In the smooth color print mode, the number of irradiation times for the color dots formed in "region 3" and "region 4" is different. However, since the irradiation intensity of the light emitted from the downstream irradiation unit 54 to the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442 is weak, the degree of curing of the color dots varies depending on the number of times of irradiation. The difference is small. In addition, the change in irradiation intensity in the printing regions (“Region 3” and “Region 4”) of the downstream nozzle row 442 is relatively gradual, and color dots with different irradiation times are dispersed by multi-pass printing. Therefore, the difference in the degree of curing of the color dots is inconspicuous. For this reason, even in the smooth color print mode, the light leaked from the downstream irradiation unit 54 to the upstream side is irradiated to the printing regions ("region 3" and "region 4") of the downstream nozzle row 442. Also, formation of a striped pattern in a color image can be suppressed.

Primer Print Mode FIG. 13 is an explanatory diagram of how dots are formed in the primer print mode. The primer print mode is a print mode in which the primer ink (background adjustment ink) is applied onto the medium M smoothly. Here, a primer print mode with 4-pass printing is shown.

In the primer print mode, in each pass, the controller 60 causes the upstream nozzle row 441 and the downstream nozzle row 442 of the primer ink nozzle row to eject the primer ink, turns on the upstream irradiation section 52, and turns on the intermediate irradiation section 53. is turned off, and the downstream irradiation section 54 (non-printing area irradiation section 55) is turned on. Then, the controller 60 causes such passes and transport operations to be performed alternately. In “Region 1” and “Region 2”, dots are formed on the medium M by the primer ink ejected from the upstream nozzle row 441, and the dots immediately after being formed are irradiated with light from the upstream irradiation unit 52, and the dots are formed. is cured (or semi-cured).

In “Region 3” and “Region 4”, dots are formed on the medium M by the primer ink ejected from the downstream nozzle row 442 . Since the intermediate irradiation unit 53 is turned off, the dots immediately after formation are hardly irradiated with light, and the dots immediately after formation are not cured. As a result, the dots formed in “region 3” and “region 4” (dots formed by the downstream nozzle row 442) gradually spread on the medium M. FIG. However, since the dots formed in "Region 1" and "Region 2" are already cured (or semi-cured), the uncured primer ink ejected in "Region 3" and "Region 4" It does not mix with the dots formed in "Region 1" and "Region 2", but spreads and wets between the already cured dots. The uncured primer ink in “region 3” and “region 4” is irradiated with light from the downstream side irradiation unit 54 in a region (for example, “region 5”) downstream of “region 4” in the transport direction. will be hardened by As a result, the smoothly applied primer ink (background adjustment ink) can be fixed on the medium M.

It should be noted that "area 3" and "area 4" corresponding to the printing area of the downstream nozzle row 442 are irradiated with the light leaked from the upstream irradiation section 52 and the downstream irradiation section 54 (see FIG. 8). , see FIG. 9). However, the irradiation intensity in most of this region has a value smaller than P1 (half the maximum value Pmax). For this reason, most of the dots formed in "area 3" and "area 4" are in a state of being difficult to cure, and therefore most of the dots are easily smoothed.

In the present embodiment, at least a part of the print region irradiation section 51 on the downstream side in the transport direction is arranged further downstream in the transport direction than the downstream end of the nozzle row 44 , and the downstream irradiation section 54 is located at the downstream end of the nozzle row 44 . is arranged on the downstream side in the conveying direction. Therefore, the irradiation intensity P3 (see the graph on the left side of FIG. 9) at the position of the downstream end of the nozzle row 44 becomes a value smaller than P1 (half value of the maximum value Pmax). (light leaking from the downstream irradiation unit 54) is relatively weak. Therefore, the dots formed in "region 4" are relatively hard to cure. Thereby, the primer ink can be applied smoothly.

By the way, a partial region on the upstream side of “region 3” is irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 . Therefore, the dots formed in a partial region on the upstream side of "region 3" are irradiated with light exceeding the irradiation intensity P1 from the upstream irradiation section 52 immediately after formation, so these dots are cured immediately after formation. (or semi-cured). However, in the primer print mode, the ink ejected from the upstream nozzle row 441 and the ink ejected from the downstream nozzle row 442 are the same. hardened dots) are almost indistinguishable from the dots formed in "Region 2". Therefore, even if the dots in a partial area on the upstream side of "area 3" are cured immediately after being formed, the irregularities on the surface of the primer ink fixed on the medium M are not affected.

In the primer printing mode, the number of irradiation times for the dots formed in "area 3" and "area 4" is different. However, since the irradiation intensity of the light emitted from the downstream irradiation unit 54 to the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442 is weak, the difference in the degree of curing of the dots due to the difference in the number of times of irradiation. is small. In addition, the change in the irradiation intensity in the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442 is relatively gentle, and dots with different irradiation times are dispersed by multi-pass printing. , the difference in the degree of curing of the dots is inconspicuous. For this reason, even in the primer printing mode, even if the light leaked from the downstream irradiation unit 54 to the upstream side is irradiated to the printing regions (“region 3” and “region 4”) of the downstream nozzle row 442, , the formation of stripes on the surface of the primer ink fixed on the medium M can be suppressed.

<Termination processing>
After all dots (dots to be formed) are formed on the medium M, some dots have not yet been irradiated with light of sufficient energy and are in a state of insufficient curing. Therefore, even after all the dots are formed on the medium M, it is necessary to irradiate the insufficiently cured dots with light. In the following description, the process of irradiating the insufficiently cured dots with light after all the dots are formed may be referred to as "terminating process".

Termination Processing of Reference Example FIGS. 14A to 14C are explanatory diagrams of termination processing of a reference example.

FIG. 14A is an explanatory diagram of a state of a pass when all dots have been formed on the medium M. FIG. The "printed area" in the figure is an area where dots to be formed on the medium M are formed, and where the dots are cured by being irradiated with light of sufficient energy. There is an area where the dots are insufficiently cured (an area where the energy of the irradiated light is smaller than that of the print-completed area) upstream of the print-completed area in the transport direction. In the following description, an area where dots to be formed on the medium M are formed and where the dots are insufficiently cured may be referred to as an "undercured area". In the "undercured area", the area closer to the "printing completed area" has a relatively large number of times of light irradiation (number of passes) from the irradiation unit 50, and a relatively large amount of already irradiated energy. Conversely, in the "undercured area", the farther from the "printing completed area", the number of times of light irradiation from the irradiation unit 50 (the number of passes) is relatively small, and the energy that has already been irradiated is relatively small. . Here, it is assumed that there are "undercured areas" of "one pass", "two passes", and "three passes" in order from the "printed area". However, depending on the number of passes in multi-pass printing, the type of print mode, the transport length (transport amount) during the transport operation, etc., there may be an "undercured area" for four or more passes. The length X (width) in the transport direction of the “undercured region” for each pass corresponds to the transport length (transport amount) during the transport operation performed when dots are formed on the medium M.

In the termination process, the insufficiently cured region shown in FIG. 14A is irradiated with light from the irradiation unit 50 . At this time, by irradiating light having a higher energy than the light emitted from the irradiation unit 50 during dot formation, the termination process can be completed early. However, in this case, the light irradiation conditions for the printed area and the light irradiation conditions for the insufficiently cured area are different, so the image quality of the printed area after printing is different from the image quality of the insufficiently cured area. Unevenness may occur. For example, if the time from the formation of dots to the irradiation of light differs between the print-completed area and the insufficiently-cured area, the way the dots wet and spread will be different, and the shape of the dots will be different. A difference in image quality occurs between the completed area and the insufficiently cured area, which may cause printing unevenness. Therefore, in the termination process, it is desirable to irradiate the insufficiently cured region with light from the irradiation unit 50 so that the same conditions as when the printed region is irradiated with light are obtained.

Therefore, in the end processing of the reference example, the controller 60 repeats the same conveying operation as during dot formation (see FIG. 14B) and the same pass as during dot formation (see FIG. 14C). Here, the controller 60 repeats the same conveying operation as in dot formation and the same pass as in dot formation three times. As shown in FIG. 14C, when the carriage 21 is moved in the scanning direction, the controller 60 turns on the irradiation unit 50 without ejecting ink from the nozzles. In the following description, such a pass for termination processing may be referred to as a "termination pass". Here, it is assumed that the downstream irradiation section 54 is turned on during dot formation, and that the downstream irradiation section 54 is also turned on during the end pass. According to the termination process of the reference example, the light irradiation conditions for the insufficiently cured region are the same as the light irradiation conditions for the printed region. The image quality becomes uniform, and printing unevenness can be suppressed.

On the other hand, in the end processing of the reference example, the conveying operation is repeated even after the formation of all dots on the medium M is completed. That is, in the end processing of the reference example, it is necessary to transport the medium M to the downstream side in the transport direction even after the formation of all dots on the medium M is completed. Therefore, in the reference example, a space is required for sending out the medium M that has been transported during the termination process.

Termination Processing of this Embodiment FIGS. 15A to 15C are explanatory diagrams of termination processing of this embodiment.

FIG. 15A is an explanatory diagram of a state of a pass when all dots have been formed on the medium M. FIG. This figure is similar to FIG. 14A of the reference example described above. Here, it is assumed that there are "undercured areas" of "one pass", "two passes", and "three passes" in order from the "printed area". Also, here, it is assumed that the downstream irradiation section 54 is turned on during dot formation.

In the termination process of the present embodiment, the controller 60 does not perform the transport operation after the previous pass (see FIG. 15A), and waits for a time corresponding to one transport operation as shown in FIG. 15B. I do. By providing such a standby operation, it is possible to adjust the time from the formation of dots in the insufficiently cured region to the irradiation of light. This time adjustment is to make the light irradiation conditions for the insufficiently cured area the same as when the printed area is irradiated with light. If it is sufficient, the standby operation can be omitted. For example, when smoothing is performed in the insufficiently cured region (when the wetting and spreading of the dots is completed), no waiting time is required for smoothing, so the waiting operation is also unnecessary.

After the standby operation, the controller 60 moves the carriage 21 in the scanning direction as shown in FIG. 15C, and turns on the irradiation section 50 without ejecting ink from the nozzles (end pass). In the terminating pass, the controller 60 changes the lighting area of the irradiating section 50 compared to the previous pass (including the terminating pass). Specifically, the lighting area of the irradiating section 50 is changed so as to be upstream of the area lit in the immediately preceding pass by the length X of the transportation for one pass in the transport direction. For example, in the pass shown in FIG. 15A, the downstream irradiation section 54 is turned on, so in the terminal pass shown in FIG. A range of length L21 on the upstream side in the transport direction is lit. That is, the controller 60 turns off the range of the length X from the downstream end of the downstream irradiation section 54 , and turns on the downstream irradiation section 54 on the upstream side in the transport direction from the extinguishing range. By lighting the range of length X on the downstream side, the range of length L21 upstream of the downstream irradiation section 54 in the transport direction by one transport length X is lit. As a result, light can be applied to the insufficiently cured region without conveying the medium M, as in the end pass of the reference example of FIG. 14C.

In this embodiment, the controller 60 performs a standby operation that waits for a time corresponding to one transport operation, and a final pass that changes the lighting area of the irradiation unit 50 compared to the immediately preceding pass (including the final pass). Repeat with alternating passes. Here, the controller 60 repeats the standby operation and the terminating pass three times. As a result, the light irradiation conditions for the insufficiently cured region shown in FIG. 15A are the same as the light irradiation conditions for the printed region, so that the image quality of the printed region and the insufficiently cured region after printing is uniform. It becomes possible to suppress printing unevenness. According to the present embodiment, since it is not necessary to transport the medium M downstream in the transport direction during the end processing, the space of the printing apparatus 1 can be reduced compared to the reference example (see FIGS. 14A to 14C). be able to.

In the present embodiment, the lighting area of the irradiation unit 50 is set so as to match the length of the insufficiently cured area in the transport direction. The lighting area of the irradiation unit 50 may be set in a range wider than the insufficiently cured area. For example, when the insufficient curing region can be included, the downstream irradiation unit 54 including the range of length X from the downstream end of the downstream irradiation unit 54 is turned on, and the downstream length of the intermediate irradiation unit 53 A range of X may be illuminated. In other words, the lighting range may be changed not only by moving (shifting) but also by increasing it. Alternatively, the upstream side may be turned on without turning off the downstream side. Further, for example, when an insufficiently cured region can be included, the downstream irradiation section 54 may be turned off while the upstream irradiation section 52 and the intermediate irradiation section 53 are turned on. In this case, light irradiation may be performed even in the print-completed area, but even if light irradiation is performed in the print-completed area, since curing has already been completed in the print-completed area, problems with print quality are unlikely to occur. . On the other hand, since it is not necessary to perform control corresponding to the lighting area of the irradiation unit 50, the image quality of the printing completed area and the insufficient curing area can be uniformed with a simple configuration, and printing unevenness can be suppressed.

<Termination processing of modified example>
In the termination process described above, the range of length L21, which is upstream in the transport direction by the transport length X for one time from the downstream irradiation unit 54, is lit (see FIG. 15C). However, the area to be lit in the termination process is not limited to this. In the modified example, the range and length of the lighting area are changed. As shown in FIG. 8, when there is a member such as the frame 50C that blocks light at the end of the lighting region, the change in irradiation intensity at that position becomes steep (for example, the graph in FIG. (see the inclination at the position of circle 2), if there is no light blocking member such as the frame 50C at the end of the lighting area, light leaks outside that position, so irradiation at that position The change in intensity (the slope at circle 3 on the graph) becomes relatively gradual. Therefore, in the pass shown in FIG. 15A (the pass for dot formation), the light leaks to the downstream side of the downstream irradiation unit 54, and in the pass for the end (first pass for the end) shown in FIG. It is considered that the area where light leaks to the downstream side is wider than the lighting area. As a result, it is considered that the amount of light irradiation tends to be slightly excessive at the upstream end of the print completion area in FIG. 15C.

16A to 16C are explanatory diagrams of the termination process of the modified example. In the modified example as well, the controller 60 performs a standby operation of waiting for a time corresponding to one transport operation, and a terminal operation in which the illuminated area of the irradiation unit 50 is changed compared to the previous pass (including the terminal pass). Repeat with alternating passes.

In the first end pass (see FIG. 16B) of the modified example, the controller 60 controls the non-printing area irradiation unit 55 (downstream irradiation unit 54) that was lit in the last dot formation pass (see FIG. 16A). ), the area to be illuminated is changed upstream in the transport direction by the transport length X for one time. However, in the modified example, the controller 60 sets the extinguishing range of the downstream end of the non-printing area irradiation unit 55 to X', which is slightly longer than the one-time transport length X, instead of the one-time transport length X. . That is, in the modified example, in the first end pass, the controller 60 turns off the range of the length X′ from the downstream end of the non-printing area irradiation section 55, and the upstream side of the turning-off range in the transport direction. By turning on the non-printing area irradiation unit 55 and by lighting the range of the length X (the conveying length for one time) on the downstream side of the intermediate irradiation unit 53, the upstream side of the non-printing area irradiation unit 55 , a range with a length L21′ slightly shorter than the non-printing area irradiation unit 55 is lit. Note that the length L21′ of the lighting region of the trailing pass is slightly shorter than the length L21 of the lighting region of the pass during dot formation (the non-printing region irradiation unit 55), but the length L21′ of the lighting region of the trailing pass is slightly shorter than the length L21 of the lighting region of the pass for dot formation. Since there is no light blocking member such as the frame 50C at the end, the light leaks to the downstream side of the lighting area, so the range irradiated with light is almost the same as the pass during dot formation. As a result, in the modified example, it is possible to prevent an excessive amount of light from being applied to the upstream end of the print completion area.

In the second and subsequent terminating passes, the controller 60 turns on the irradiating section 50 so that it is upstream in the conveying direction by the conveying length X for one time from the region lit in the last terminating pass. This will change the area where the For example, in the second terminal pass shown in FIG. 16C, the controller 60 moves the irradiating section 50 to the upstream side in the conveying direction by one conveying length X compared to the first terminal pass. A range of length L21' is lit. Also, in the second termination pass shown in FIG. 16C, the controller 60 causes the downstream end side unlit region to be extinguished by one transport length X compared to the downstream end side unlit region in the first termination pass. lengthens the

In the modified example as well, the insufficiently cured region can be irradiated with light as in the end pass of the reference example of FIG. 14C without conveying the medium M. Also in the modified example, since the medium M does not have to be transported downstream in the transport direction during the end processing, the space of the printing apparatus 1 can be saved compared to the reference example (see FIGS. 14A to 14C). be able to.

=== Second Embodiment ===
FIG. 17 is an explanatory diagram of the configuration of the second embodiment. In the second embodiment, the length of the print area irradiation section 51' is the same as the length of the nozzle row 44', the length of the upstream irradiation section 52' is the same as the length of the upstream nozzle row 441', The length of the intermediate irradiation section 53' is the same as the length of the downstream nozzle row 442'. Therefore, the position of the downstream end of the nozzle row 44' is set at the boundary between the intermediate irradiation section 53' and the downstream irradiation section 54'. For this reason, in the above-described embodiment, at least a portion of the print area irradiation section 51 on the downstream side in the transport direction (in other words, at least a portion of the intermediate irradiation section 53 on the downstream side in the transport direction) is positioned further than the downstream end of the nozzle row 44. While it is arranged on the downstream side in the conveying direction, the second embodiment does not have such a configuration.

In such a second embodiment, when the non-printing area irradiation section 55' (downstream irradiation section 54') is turned off while the printing area irradiation section 51' is turned on, the irradiation at the position of the downstream end of the nozzle row 44 The intensity will be approximately P1. Further, even when the non-printing area irradiating section 55' is turned on while the printing area irradiating section 51' is turned off, the irradiation intensity at the position of the downstream end of the nozzle row 44' is approximately P1. Thus, in this embodiment, the irradiation intensity at the downstream end of the nozzle row 44' when the non-printing area irradiation section 55' is turned on while the printing area irradiation section 51' is turned off is is turned on and the non-printing area irradiation unit 55' is turned off, the irradiation intensity at the same position becomes P1, which is substantially the same.

In the second embodiment as well, the controller 60 ejects ink from the nozzle row 44' while irradiating the non-printing area during dot formation in the gross print mode (see FIG. 10B) or the mixed print mode (see FIGS. 11 to 13). A pass for lighting the section 55' (downstream irradiation section 54') and a conveying operation are alternately performed. Also in the second embodiment, the medium M does not need to be conveyed if the above-described end processing (FIGS. 15A to 15C and FIGS. 16A to 16C) is performed after all the dots to be formed on the medium are formed. Also, light can be applied to the insufficiently cured region in the same manner as the end path of the reference example of FIG. 14C.

=== Third Embodiment ===
<Positional Relationship Between Nozzle Row and Irradiation Unit 50 of Third Embodiment>

FIG. 18 is an explanatory diagram of the arrangement of the nozzle rows and the irradiation unit 50 according to the third embodiment.

The head 41 has a color head 41A and a special head 41B. The color head 41A has a color ink nozzle row 44A that ejects color ink. The special head 41B has a special ink nozzle array 44B that ejects special ink (clear ink such as gloss ink or primer ink, white ink, silver ink, or the like). The color ink nozzle row 44A and the special ink nozzle row 44B have the same length in the transport direction. In the following description, the length of each of the color ink nozzle row and the special ink nozzle row in the transport direction is assumed to be L12 (length L12 is approximately the same as length L11 described above).

In the third embodiment, the special head 41B is arranged upstream of the color head 41A in the transport direction. Here, the upstream end of the color ink nozzle row 44A (the most upstream nozzle among the plurality of nozzles that make up the color ink nozzle row 44A) and the downstream end of the special ink nozzle row 44B (the plurality of nozzles that make up the special ink nozzle row 44B). (most downstream nozzles among the nozzles of 1) are located at substantially the same position in the transport direction. That is, in the third embodiment, the color ink nozzle array 44A and the special ink nozzle array 44B are staggered (in contrast, in the first embodiment, the color ink nozzle array and the special ink nozzle array are arranged in the scanning direction). placed side by side).

Also in the third embodiment, an irradiation unit 50 is provided on the lower surface of the carriage 21 . The irradiation section 50 of the third embodiment has the same configuration as the irradiation section 50 of the first embodiment, and includes an LED array 50A, a lens array 50B, and a frame 50C (see FIG. 3A). The central portion of the irradiation section 50 (the central portion of the intermediate irradiation section 53), the upstream end of the color ink nozzle row 44A, and the downstream end of the special ink nozzle row 44B are substantially at the same position in the transport direction.

Also in the third embodiment, the irradiation unit 50 is divided into three, an upstream irradiation unit 52, an intermediate irradiation unit 53, and a downstream irradiation unit 54, and the controller 60 controls the upstream irradiation unit 52 divided into three. , the intermediate irradiation unit 53 and the downstream irradiation unit 54 can be controlled to turn on and off.

In the third embodiment, the combination of the upstream irradiation section 52 and the intermediate irradiation section 53 includes the range in the transport direction of the special ink nozzle row 44B that ejects the special ink. Therefore, in the third embodiment, the print area irradiation section 51 corresponding to the special ink nozzle row 44B is a combination of the upstream irradiation section 52 and the intermediate irradiation section 53 . Further, the downstream irradiation section 54 does not overlap the range in the transport direction of the special ink nozzle row 44B, and is arranged downstream in the transport direction from the special ink nozzle row 44B. Therefore, in the third embodiment, the non-printing region irradiation section 55 corresponding to the special ink nozzle row 44B is the downstream irradiation section 54 .

FIG. 19 is a diagram showing the positional relationship between the nozzle rows and the irradiation section 50. As shown in FIG. The positions of the color ink nozzle row 44A and the special ink nozzle row 44B are shown on the right side of the figure. The positions of the irradiation units 50 (the upstream irradiation unit 52, the intermediate irradiation unit 53, and the downstream irradiation unit 54) are shown in the center of the drawing. A graph of the irradiation intensity of the irradiation unit 50 is shown on the left side of the figure. The irradiation intensity distribution when each region of the irradiation unit 50 is lit or extinguished is the same as that of the above-described first embodiment (see FIG. 8).

In the third embodiment, the irradiation section 50 (the upstream irradiation section 52, the intermediate irradiation section 53, and the downstream irradiation section 54) is configured to move all the nozzle rows configured from the color ink nozzle row 44A and the special ink nozzle row 44B in the conveying direction. are arranged to encompass the range of Further, the positions of the upstream ends of the nozzle rows (the color ink nozzle row 44A and the special ink nozzle row 44B) are set downstream in the transport direction from the position of the upstream end of the irradiation section 50 (upstream end of the upstream irradiation section 52). It is Further, the positions of the downstream ends of the nozzle rows (the color ink nozzle row 44A and the special ink nozzle row 44B) are set upstream in the transport direction from the position of the downstream end of the irradiation section 50 (the downstream end of the downstream irradiation section 54). It is Therefore, when the upstream irradiation unit 52, the intermediate irradiation unit 53, and the downstream irradiation unit 54 are all turned on, the irradiation intensity exceeding P1 is not in the area printed by the color ink nozzle row 44A and the special ink nozzle row 44B. Light (light having an irradiation intensity close to the maximum value Pmax) is emitted. That is, when the upstream irradiation section 52, the intermediate irradiation section 53, and the downstream irradiation section 54 are all turned on, the area printed by the color ink nozzle row 44A and the special ink nozzle row 44B is hardened with photocurable ink. The light that can be used is irradiated.

Further, in the third embodiment, the position of the downstream end of the special ink nozzle row 44B (the most downstream nozzle among the plurality of nozzles forming the special ink nozzle row 44B) is set on the upstream side in the conveying direction of the boundary between the two. That is, at least a portion of the print region irradiation section 51 on the downstream side in the transport direction (in other words, at least a portion of the intermediate irradiation section 53 on the downstream side in the transport direction) is located downstream in the transport direction from the downstream end of the special ink nozzle row 44B. are placed in Further, the downstream irradiation section 54 is arranged downstream in the transport direction with a gap from the downstream end of the special ink nozzle row 44B. Therefore, even in the third embodiment, when the downstream irradiation unit 54 is turned on while the print area irradiation unit 51 is turned off, the irradiation intensity P4 at the downstream end position of the special ink nozzle row 44B is P1 ( half the maximum value Pmax). Note that the irradiation intensity P4 in the third embodiment is a value smaller than the irradiation intensity P3 in the first embodiment (for this reason, in the third embodiment, dots formed with special ink are used more than in the first embodiment). is easier to smooth).

<Color print mode and special print mode of the third embodiment>
FIG. 20A is an explanatory diagram of how dots are formed in the color print mode of the third embodiment. Here, the state of 4-pass printing is shown. Although only one color ink nozzle row 44A is shown in the drawing, the other color ink nozzle rows also eject color ink in the same manner as this color ink nozzle row.

Also in the third embodiment, in the color print mode, the controller 60 ejects color ink from all the nozzles of the color ink nozzle row 44A in each pass, and also causes the intermediate irradiation section 53 and the downstream side irradiation section 54 (color ink The print area irradiation section corresponding to the nozzle row 44A) is turned on. In the color print mode, since there is no demand for smoothing and it is sufficient to cure the dots, the upstream irradiation section 52 (the non-printing area irradiation section corresponding to the color ink nozzle row 44A) may be turned on. Then, the controller 60 alternately performs such a pass and the transport operation. In "Region 1" to "Region 4", color dots are formed on the medium M with color ink, and the color dots immediately after being formed are irradiated with light from the intermediate irradiation unit 53 and the downstream irradiation unit 54, and the color dots are formed. It will be cured (or semi-cured). In "Region 2" to "Region 4", color dots are formed in the regions where color dots were formed in the previous pass. However, since the color dots formed in the previous pass are cured by being irradiated with light immediately after formation, when further color dots are formed in "area 2" to "area 4", the color dots blur. You can put it in a difficult situation.

In the color print mode of the third embodiment, the controller 60 controls not only the intermediate irradiation section 53 and the downstream irradiation section 54 (printing region irradiation section corresponding to the color ink nozzle row 44A), but also the upstream irradiation section 52 (color ink A non-printing area irradiation section corresponding to the nozzle row 44A is also lit. However, as long as the light energy with which the color dots are irradiated is sufficient, the controller 60 may turn off the upstream irradiation section 52 in the color print mode.

FIG. 20B is an explanatory diagram of how dots are formed in the special print mode according to the third embodiment.

In the special print mode, the controller 60 causes the special ink to be ejected from all the nozzles of the special ink nozzle row 44B in each pass, and the print region irradiation unit 51 (upstream irradiation unit 52 and The downstream irradiation section 54 is turned on while the intermediate irradiation section 53) is turned off. Then, the controller 60 alternately performs such a pass and the transport operation. Special dots are formed on the medium M with the special ink in "area 1" to "area 4". In the special print mode, since the print area irradiation unit 51 is turned off, the special dots immediately after being formed are hardly irradiated with light, and the special dots immediately after being formed are not cured. As a result, the special dots gradually wet and spread on the medium M and are smoothed. In "region 2" to "region 4", special dots are formed in the regions where special dots were formed in the previous pass. However, since the special dots formed in the previous pass are uncured, when further special dots are formed in "region 2" to "region 4", the uncured special inks are mixed and connected. When adjacent dots connect, the surface becomes smooth. As a result, when all the special dots to be formed in the "area 4" are formed, a special ink film (glossy film, glossy layer) with a smooth surface is formed. Then, the special ink film with a smooth surface is applied to the non-printing area irradiation section 55 (the downstream irradiation section 54 ), it is cured by being irradiated with light. Thereby, a glossy layer having a smooth surface can be formed on the medium M.

In the third embodiment, at least a portion of the print region irradiation section 51 on the downstream side in the transport direction is arranged further downstream in the transport direction than the downstream end of the special ink nozzle row 44B, and the downstream irradiation section 54 is arranged on the downstream side in the transport direction. It is arranged downstream in the transport direction from the downstream end of the row 44B. Therefore, the irradiation intensity P4 (see the graph on the left side of FIG. 19) at the position of the downstream end of the special ink nozzle row 44B becomes a value smaller than P1 (half value of the maximum value Pmax). )” (light leaking from the downstream irradiation section 54, which is the non-printing area irradiation section 55) is relatively weak. Therefore, the special dots formed in "region 4" are in a state of being relatively difficult to cure. Therefore, the special dots formed in the "area 4" are easily spread and smoothed, so that a special ink film (glossy layer) having a smooth surface can be stably formed.

In the above-described third embodiment, by staggering the color ink nozzle row 44A and the special ink nozzle row 44B, it is possible to reduce the number of nozzles and achieve both the color print mode and the special print mode. Further, in the third embodiment, by adopting a staggered arrangement in which the special ink nozzle row 44B is arranged upstream of the color ink nozzle row 44A in the transport direction, color dots immediately after being formed in the color print mode can be formed. The downstream irradiation section 54 that irradiates light can be used as the non-printing area irradiation section 55 in the special print mode.

<Termination processing of the third embodiment>
21A to 21C are explanatory diagrams of termination processing of the third embodiment.

Also in the termination process of the third embodiment, the controller 60 does not perform the transport operation after the previous pass (see FIG. 21A), and waits for a time corresponding to one transport operation as shown in FIG. 21B. Standby operation is performed. By providing such a standby operation, it is possible to adjust the time from the formation of dots in the insufficiently cured region to the irradiation of light. This time adjustment is to make the light irradiation conditions for the insufficiently cured area the same as when the printed area is irradiated with light. If it is sufficient, the standby operation can be omitted. For example, when smoothing is performed in the insufficiently cured region (when the wetting and spreading of the dots is completed), no waiting time is required for smoothing, so the waiting operation is also unnecessary.

After the standby operation, the controller 60 moves the carriage 21 in the scanning direction as shown in FIG. 21C, and turns on the irradiation section 50 without ejecting ink from the nozzles (end pass). In the terminating pass, the controller 60 changes the lighting area of the irradiating section 50 compared to the previous pass (including the terminating pass). Specifically, the lighting area of the irradiating section 50 is changed so as to be upstream of the area lit in the immediately preceding pass by the length X of the transportation for one pass in the transport direction. As a result, even in the termination processing of the third embodiment, light can be applied to the insufficiently cured region without transporting the medium M, as in the termination processing of the first embodiment.

In addition, in the termination process of the third embodiment, as in the termination process of the first embodiment, the lighting area of the irradiation unit 50 is set so as to match the length of the insufficiently cured area in the conveying direction. However, the lighting area of the irradiating unit 50 may be set in a range wider than the insufficiently cured area as long as the area includes the insufficiently cured area. In this case, light irradiation may be performed even in the print-completed area, but even if light irradiation is performed in the print-completed area, since curing has already been completed in the print-completed area, problems with print quality are unlikely to occur. (Especially in a special print mode that smoothes dots, print quality problems are less likely to occur). On the other hand, since it is not necessary to perform control corresponding to the lighting area of the irradiation unit 50, the image quality of the printing completed area and the insufficient curing area can be uniformed with a simple configuration, and printing unevenness can be suppressed.

＝＝＝Summary＝＝＝
The printing apparatus 1 of the above-described embodiments (first to third embodiments) includes a transport section 30, a head 41, an irradiation section 50, and a controller 60 (control section). The irradiation unit 50 can irradiate a region longer in the transport direction than the nozzle row 44, and the controller 60 controls the irradiation unit 50 to be a print area irradiation unit 51 and a non-print area irradiation unit 55 (downstream irradiation unit 54). It is possible to control lighting and extinguishing of each by dividing into two. In the gross print mode (see FIG. 10B) or the mixed print mode (see FIGS. 11 to 13), the controller 60 causes the head 41 to move in the scanning direction while ejecting ink from the nozzle rows 44 while irradiating the non-printing area. A pass for lighting the portion 55 and a conveying operation are alternately performed. Since the non-printing area irradiation unit 55 is arranged downstream of the downstream end of the nozzle row 44 in the transport direction (see FIGS. 9 and 17), by alternately performing the pass and the transport operation, it is possible to reduce the number of dots. The dots can be irradiated with light after a predetermined time has elapsed after formation, and the dots can be cured after the dots are smoothed. On the other hand, as shown in FIGS. 15A and 16A, after all the dots (dots to be formed) have been formed on the medium M, some dots have not yet been irradiated with light of sufficient energy and are hardened. become deficient. Therefore, in the above embodiment, the insufficiently cured dots are irradiated with light by performing the termination pass. In the above-described embodiment, in the end pass, the controller 60 changes the region to be irradiated with light so as to include the region on the upstream side in the transport direction from the lighting region of the previous pass (including the end pass). In this state, the head 41 is moved in the scanning direction and light is emitted from the irradiation unit 50 without ejecting ink. As a result, the insufficiently cured region can be irradiated with light without transporting the medium M. According to the above-described embodiment, it is not necessary to transport the medium M to the downstream side in the transport direction during the end processing. can be planned.

In the above embodiment, the controller 60 alternately performs the waiting operation for a predetermined time (see FIG. 15B) and the termination pass. By performing the standby operation in this way, it is possible to adjust the time from the formation of the dots in the insufficiently cured region to the irradiation of the light.

In the above embodiment, the standby time in the standby operation is set to the time corresponding to one transport operation (see FIG. 15B). If the standby time is shorter than the time corresponding to one transport operation, the time from the formation of the dots in the insufficiently cured area to the irradiation of light will be shortened, and the print completed area will be shortened. Since the light is irradiated in a state that is not smoothed compared to the dots, the shape of the dots differs between the printed area and the insufficiently cured area after printing is completed (resulting in uneven printing). Also, if the standby time is longer than the time corresponding to one transport operation, the dots in the insufficiently cured area are smoothed compared to the dots in the printed area. and the under-cured region have different dot shapes. On the other hand, if the standby time is a time corresponding to one transport operation as in the present embodiment, the light irradiation conditions for the insufficiently cured region shown in FIGS. Since the conditions are the same as the light irradiation conditions, the image quality of the printed area and the insufficiently cured area becomes uniform after printing is completed, and printing unevenness can be suppressed. However, the standby time does not necessarily have to be the time corresponding to one transport operation.

In the above-described embodiment, in the end pass, the controller 60 changes the lighted region upstream in the transport direction from the lighted region of the immediately preceding pass (including the end pass) by one transport length X. ing. As a result, even if the medium is not conveyed, light can be irradiated in the same manner as when the medium is conveyed. Since the conditions are the same as the light irradiation conditions for the area, the image quality of the printed area and the insufficiently cured area after printing is uniform, and printing unevenness can be suppressed.

In the above modified example, in the first end pass, when changing the lighting region to the upstream side in the transport direction from the downstream irradiation unit 54 by the transport length X for one transport, A range of X' slightly longer than X is extinguished. As a result, it is possible to prevent an excessive amount of light from being irradiated to the upstream end of the print completion area.

=== Other Embodiments ===
The above embodiments are presented as examples and are not intended to limit the scope of the invention. The above configurations can be implemented in combination as appropriate, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. The above-described embodiments and modifications thereof are included in the invention described in the claims and their equivalents, as well as being included in the scope and gist of the invention.

1 printing device,
20 carriage part, 21 carriage,
22 carriage motor, 24 carriage guide,
30 transport unit, 31 transport roller,
32 transport motor, 34 pinch roller,
40 printing unit, 41 head,
41A color head, 41B special head,
42 head driving unit, 44 nozzle row,
44A color ink nozzle row, 44B special ink nozzle row 44B,
441 upstream nozzle row, 442 downstream nozzle row,
45 nozzle, 50 irradiation unit,
50A LED array, 50B lens array, 50C frame,
51 print region irradiation unit, 52 upstream irradiation unit,
53 intermediate irradiation section, 54 downstream irradiation section,
55 non-printing irradiation section,
60 controller, 70 computer,
100 printing system, M medium

Claims (5)

a transport unit that transports the medium in the transport direction;
a head having a nozzle row in which a plurality of nozzles are arranged in the carrying direction and movable in the scanning direction;
an irradiating unit that irradiates a region longer in the transport direction than the nozzle row with light and is movable in the scanning direction together with the head;
A pass for irradiating the light from the irradiation unit while ejecting ink from the nozzle while moving the head in the scanning direction and a transport operation for transporting the medium in the transport direction by the transport unit are alternately performed. and a control unit,
The control unit divides the irradiation unit into a printing area irradiation unit and a non-printing area irradiation unit adjacent to the downstream side of the printing area irradiation unit in the transport direction, and can control lighting and extinguishing of each,
The print area irradiation unit includes the range of the nozzle row in the transport direction,
The non-printing area irradiation unit is arranged downstream in the transport direction from a downstream end of the nozzle row in the transport direction,
The control unit
By alternately performing the pass in which the non-printing area irradiation unit is turned on to irradiate the light while ejecting ink from the nozzles while moving the head in the scanning direction, and the conveying operation, the After forming all the dots to be formed on the medium,
While maintaining the relative position in the transport direction between the medium and the head, lighting is performed so as to include an upstream region in the transport direction from the region in which the non-printing region irradiation unit was lit in the previous pass. A printing apparatus, wherein a pass is performed in which the light is emitted from the irradiation section without ejecting ink from the nozzles while moving the head in the scanning direction while changing the area. The printing device according to claim 1, wherein
The control unit
By alternately performing the pass in which the non-printing area irradiation unit is turned on to irradiate the light while ejecting ink from the nozzles while moving the head in the scanning direction, and the conveying operation, the After forming all the dots to be formed on the medium,
standby operation for a predetermined time;
While moving the head in the scanning direction in a state in which the lighting region is changed so as to include a region on the upstream side in the transport direction from the region in which the non-printing region irradiation unit was lit in the previous pass, A printing apparatus characterized by alternately performing passes in which the light is emitted from the irradiation unit without ejecting ink from the nozzles. The printing device according to claim 2,
The printing apparatus, wherein the predetermined time in the standby operation is a time corresponding to one transport operation. The printing device according to any one of claims 1 to 3,
The control unit
By alternately performing the pass in which the non-printing area irradiation unit is turned on to irradiate the light while ejecting ink from the nozzles while moving the head in the scanning direction, and the conveying operation, the After forming all the dots to be formed on the medium,
In a state in which the lighting region is changed so as to include a region on the upstream side in the transport direction by the transport length of one time from the region in which the non-printing region irradiation unit is lit in the previous pass, A printing apparatus, wherein a pass is performed in which the light is emitted from the irradiation section without ejecting ink from the nozzles while moving the head in the scanning direction. The printing device according to claim 4,
The control unit
By alternately performing the pass in which the non-printing area irradiation unit is turned on to irradiate the light while ejecting ink from the nozzles while moving the head in the scanning direction, and the conveying operation, the After forming all the dots to be formed on the medium,
When changing the lighting region so as to include a region upstream in the transport direction by the transport length of one time from the non-printing region irradiation unit that was lit in the pass during the last dot formation, In a state in which a range longer than one transport length from the downstream end of the non-printing region irradiation section is turned off, the head is moved in the scanning direction, and the ink is not ejected from the nozzles, and the ink is not discharged from the irradiation section. A printing apparatus characterized by performing a first terminal pass for irradiating light.

Images