Inkjet printer

Abstract

An inkjet printer 10 comprises: a support base 20 that supports a heat-foamable recording medium 5; a first storage container 51A that stores a colorless transparent foaming inhibitor for inhibiting foaming of the recording medium 5; a discharge head 60 in which a first nozzle group 62A, which downwardly discharges the foaming inhibitor stored in the first storage container 51A, is located above the support base 20; a heating device 80 that heats the recording medium 5; an ultraviolet light source 110 that is located above the support base 20 and that emits light including ultraviolet light that makes the foaming inhibitor visible; and an operation circuit 130 that turns on the ultraviolet light source 110. The operation circuit 130 includes a power supply 131, a first power supply line 132 connecting the power supply 131 and the ultraviolet light source 110, and three or more resistors 135 arranged in series on the first power supply line 132.

Description

Inkjet printer

[0001] The present invention relates to an inkjet printer.

[0002] For example, Patent Document 1 discloses a method of forming a printed product including convex portions and regions other than the convex portions using a foaming medium provided with a foaming layer that generates gas upon heating. In the method described in Patent Document 1, a foaming suppression ink that penetrates into the foaming layer and chemically suppresses foaming is used. In the method described in Patent Document 1, in embossing data, for regions outside the regions that become convex portions, ejection of the foaming suppression ink is specified, and for regions within the regions that become convex portions, non-ejection of the foaming suppression ink is specified, thereby forming convex portions and regions other than the convex portions on the foaming medium.

[0003] Further, for example, Patent Document 2 discloses an inkjet printer including a platen, an ink head that ejects ink onto a recording medium on the platen, and a plurality of light sources disposed above the platen. The inkjet printer described in Patent Document 2 is configured to turn on the light sources during printing and during test printing. The light sources are turned on so that the state of the recording medium can be easily visually recognized in situations including during printing and during test printing.

[0004] Japanese Patent Application Laid-Open No. 2020-138498, Japanese Patent Application Laid-Open No. 2017-043057

[0005] The foaming suppression ink as disclosed in Patent Document 1 is generally colorless and transparent. Therefore, for example, even when the light source is turned on during test printing of the foaming suppression ink, the user cannot visually confirm the state of the foaming suppression ink. It is known that the foaming suppression ink can be visually observed when irradiated with ultraviolet light. Thus, by providing a light source that irradiates ultraviolet light and turning it on, the state of the foaming suppression ink in the inkjet printer can be visually confirmed. However, since strong ultraviolet light has safety problems, it is necessary to reliably limit the intensity of the ultraviolet light.

[0006] The present invention has been made in view of the above, and its object is to provide an inkjet printer equipped with a light source that irradiates ultraviolet light for visual inspection of a colorless, transparent foaming inhibitor, and which can more reliably limit the intensity of ultraviolet light.

[0007] The inkjet printer disclosed herein comprises a support base for supporting a heat-expandable recording medium; a first storage container for storing a colorless, transparent foam inhibitor that suppresses foaming of the recording medium; a discharge head positioned above the support base, having a first nozzle group for discharging the foam inhibitor stored in the first storage container downward; a heating device for heating the recording medium; an ultraviolet light source positioned above the support base for irradiating light containing ultraviolet light that makes the foam inhibitor visible; and an operating circuit for turning on the ultraviolet light source. The operating circuit comprises a power supply; a first power line connecting the power supply and the ultraviolet light source; and three or more resistors arranged in series on the first power line.

[0008] According to the inkjet printer described above, three or more resistors are arranged in series on the first power line connecting the power supply and the ultraviolet light source. The three or more resistors arranged in series on the first power line determine the current flowing through the ultraviolet light source and limit the output of the ultraviolet light source. Furthermore, because there are three or more resistors, even if one of the resistors on the first power line is short-circuited, the increase in the current flowing through the ultraviolet light source can be kept to a minimum. Therefore, the increase in the intensity of ultraviolet light emitted by the ultraviolet light source can be kept to a minimum. Thus, according to the inkjet printer disclosed herein, the intensity of ultraviolet light can be more reliably limited by the three or more resistors arranged in series on the first power line.

[0009] This is a front view of an inkjet printer according to one embodiment. This is a schematic cross-sectional view of the printer. This is a schematic plan view of the printer. This is a graph showing the intensity distribution of light generated by an ultraviolet light source. This is a partially broken perspective view of the printer cut along a vertical plane passing through a support member. This is a circuit diagram of the operating circuit.

[0010] The following describes an inkjet printer according to one embodiment, with reference to the drawings. It should be noted that the embodiment described herein is not intended to particularly limit the present invention. Furthermore, the same reference numerals are used for components and parts that perform the same function, and redundant explanations are omitted or simplified as appropriate.

[0011] [Configuration of the Inkjet Printer] Figure 1 is a front view of an inkjet printer 10 (hereinafter simply referred to as printer 10) according to one embodiment. Figure 2 is a schematic cross-sectional view of printer 10. Figure 3 is a schematic top view of printer 10. The printer 10 according to this embodiment is a printer that ejects color ink and foam-suppressing ink onto a heat-foaming recording medium 5, and heats the recording medium 5 to create a printed output with an uneven surface. In the following description, left, right, up, and down refer to the left, right, up, and down directions as seen from the perspective of a user standing in front of printer 10. The direction approaching the user from printer 10 is considered the front, and the direction moving away from the user is considered the rear. The symbols F, Rr, L, R, U, and D in the drawings indicate the front, rear, left, right, up, and down of printer 10, respectively. However, these directions are merely defined for the convenience of explanation and do not limit the installation configuration of printer 10 in any way.

[0012] The recording medium 5 is a heat-expandable recording medium that rises when heated due to foaming. The recording medium 5 has a base portion made of, for example, a film, and a heat-expandable layer. The heat-expandable layer is formed, for example, by heat-expandable microcapsules coated on the base portion. The heat-expandable layer contains a foaming agent and additives. The foaming agent may be, for example, 0.1 to 10 parts by weight per 100 parts by weight of a polyolefin material with an elastic modulus of less than 0.1 GPa. The foaming agent is selected from azodicarbonamide and / or their metal salts, hydrazodicarbonamide, sodium bicarbonate, trihydrazino-sym-triazine, pp'-oxybisbenzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, azobisisobutyl-oddinitrile, p-toluenesulfonyl hydrazide, bisbenzenesulfonyl hydrazide, etc. The polyolefin material is selected from thermoplastic elastomer polyolefins, ethylene-vinyl acetate copolymers, atactic polypropylene polymers, or mixtures thereof. The thickness of the heat-foamed layer is preferably, for example, 0.05 mm to 0.3 mm. The amount of additive is preferably, for example, 0 to 200 parts by weight.

[0013] As shown in Figures 1 to 3, the printer 10 according to this embodiment includes a housing 15, a platen 20, a supply roll 30, a winding roll 35, a transport device 40, an ink supply device 50, an ejection head 60, a head moving device 70, a heating device 80, a flashing stage 90, a lighting device 100, and a control device 150.

[0014] The housing 15 houses the platen 20, transport device 40, ink supply device 50, ejection head 60, head moving device 70, flashing stage 90, and lighting device 100. The housing 15 may house only a portion of the platen 20, for example, the portion below the ejection head 60. As shown in Figure 1, the housing 15 extends in the left-right direction. The housing 15 has a front opening 16 on its front surface. The front opening 16 is for transporting the recording medium 5 to the outside of the housing 15. The front opening 16 is also for making the inside of the housing 15 visible. A front cover 17 is provided in the front opening 16. The front cover 17 rotates vertically on its rear end as an axis to open and close the front opening 16. However, the configuration of the front cover 17 is not limited to this. The front cover 17 may be configured to open and close the front opening 16 by sliding, for example. The front cover 17 is configured to transmit light emitted by the ultraviolet light source 110 and the white light source 120 (both described later) of the lighting device 100. The user can see inside the housing 15 through the front cover 17. The front cover 17 is made of, for example, transparent acrylic.

[0015] The platen 20 is a support base for the recording medium 5. The platen 20 extends in the front-rear and left-right directions. The recording medium 5 is placed on the platen 20. Ink is ejected from the ejection head 60 toward the recording medium 5 on the platen 20. In this embodiment, the recording medium 5 is unwound from the supply roll 30, transported on the platen 20 by the transport device 40, and then wound onto the winding roll 35. The supply roll 30 rotatably supports the rolled recording medium 5. As shown in Figure 2, the transport device 40 includes a grit roller 41 embedded in the platen 20, a pinch roller 42 positioned opposite the grit roller 41, and a transport motor 43 that rotates the grit roller 41 in the front-rear direction. The transport device 40 transports the recording medium 5 in the front-rear direction by sandwiching the recording medium 5 between the grit roller 41 and the pinch roller 42 and rotating the grit roller 41. Hereinafter, the front-rear direction may be referred to as the transport direction X as appropriate. In this embodiment, the front is downstream in the transport direction X.

[0016] The ink supply device 50 supplies foam-suppressing ink and color ink to the ejection head 60. As shown in Figure 1, the ink supply device 50 includes an ink cartridge 51A for storing foam-suppressing ink, a plurality of ink cartridges 51B to 51E for storing color ink, and ink supply passages 52A to 52E that connect the ink cartridges 51A to 51E to the ejection head 60, respectively. Ink cartridge 51A is an example of a first storage container for storing foam-suppressing agent. Ink cartridges 51B to 51E are examples of second storage containers for storing color ink.

[0017] The foam-suppressing ink is ejected by the ejection head 60 to areas of the recording medium 5 that are not to be raised. In the areas of the recording medium 5 where the foam-suppressing ink was not ejected, a convex region with a three-dimensional shape is formed by heating of the recording medium 5. In the areas of the recording medium 5 where the foam-suppressing ink was ejected, a non-convex region is formed that is recessed compared to the convex region. The foam-suppressing ink is a colorless and transparent ink. The foam-suppressing ink is, for example, an aqueous ink suitable for the polyolefin surface that forms the heat-foamed layer of the recording medium 5. However, the foam inhibitor is not particularly limited, except that it is a colorless and transparent liquid that suppresses foaming of the recording medium 5.

[0018] Multiple ink cartridges 51B to 51E each store cyan, magenta, yellow, and black color inks. However, the types of color inks are not particularly limited. The color inks may include, for example, light cyan ink, light magenta ink, light yellow ink, gray ink, etc. The ink used in the printer 10 may also include, for example, special color inks such as white ink. The color inks are ejected by the ejection head 60 to form an image on the recording medium 5.

[0019] The ejection head 60 is positioned above the platen 20 and ejects ink downwards. The ejection head 60 is mounted on a carriage 65 that moves in the left-right direction. The carriage 65 is positioned above the platen 20. The ejection head 60 moves in the left-right direction together with the carriage 65. Hereafter, the left-right direction will also be referred to as the scanning direction Y.

[0020] As shown in Figure 3, the ejection head 60 is equipped with a plurality of ink heads 61A to 61E. The plurality of ink heads 61A to 61E are arranged in a line in the scanning direction Y. Each of the plurality of ink heads 61A to 61E extends in the transport direction X. In this embodiment, ink head 61A ejects foam-suppressing ink. Ink heads 61B to 61E each eject color ink. The ink head 61A that ejects foam-suppressing ink and the ink heads 61B to 61E that eject color ink are arranged so that their positions in the transport direction X are offset (a so-called staggered arrangement). The ink head 61A that ejects foam-suppressing ink is positioned behind the ink heads 61B to 61E that eject color ink.

[0021] The ink head 61A is equipped with a plurality of nozzles 62A arranged in the transport direction X. The plurality of nozzles 62A constitute a nozzle row 63A extending in the transport direction X. Foam-suppressing ink is discharged downward from each of the plurality of nozzles 62A. The nozzles 62A of the nozzle row 63A are an example of a first nozzle group that discharges foam-suppressing agent stored in a first storage container downward.

[0022] The ink head 61B also has a plurality of nozzles 62B arranged in the transport direction X. The plurality of nozzles 62B constitute a nozzle row 63B extending in the transport direction X. Cyan ink is ejected downward from each of the plurality of nozzles 62B. Similarly, the ink head 61C has a nozzle row 63C consisting of a plurality of nozzles 62C each ejecting magenta ink. The ink head 61D has a nozzle row 63D consisting of a plurality of nozzles 62D each ejecting yellow ink. The ink head 61E has a nozzle row 63E consisting of a plurality of nozzles 62E each ejecting black ink. The nozzles 62B to 62E of nozzle rows 63B to 63E are an example of a second nozzle group that ejects color ink stored in a second storage container downward.

[0023] However, the configuration of the discharge head 60 is not particularly limited as long as it includes a first nozzle group for discharging foam inhibitor and a second nozzle group for discharging color ink. For example, each ink head of the discharge head may have multiple nozzle rows. The ink heads 61A and 61B to 61E may be aligned in the transport direction X.

[0024] The head moving device 70 moves the carriage 65 in the scanning direction Y. As shown in Figure 1, the head moving device 70 includes a guide rail 71 extending in the scanning direction Y. The carriage 65 is slidably engaged with the guide rail 71 in the scanning direction Y. The head moving device 70 includes a scan motor (not shown) that moves the carriage 65 along the guide rail 71.

[0025] The heating device 80 is located in front of the platen 20. The heating device 80 heats the recording medium 5 on which the color ink and foam-suppressing ink have been ejected on the platen 20. As shown in Figure 2, the heating device 80 comprises a box-shaped heating device body 81 and a plurality of ceramic heaters 82 (see Figure 1). The heating device body 81 is provided with an inlet and an outlet for the recording medium 5 being transported. The plurality of ceramic heaters 82 are located inside the heating device body 81, facing the transport path of the recording medium 5. As shown in Figure 1, the plurality of ceramic heaters 82 are arranged in the scanning direction Y.

[0026] The flushing stage 90 receives the foam-suppressing ink and color ink ejected by the ejection head 60. The flushing stage 90 is a component for ink ejection for cleaning the nozzles 62A to 62E, so-called flushing, which is performed at times other than printing. As shown in Figure 3, the flushing stage 90 is positioned alongside the platen 20 in the scanning direction Y. Here, the flushing stage 90 is positioned to the right of the platen 20. The carriage 65 and ejection head 60 move along the guide rail 71 within a range that includes the position above the platen 20 and the position above the flushing stage 90. Although not shown, the home position of the carriage 65 and ejection head 60 is set further to the right of the flushing stage 90. Below the home position, there is a cap (not shown) that is attached to the ejection head 60. The printer 10 also includes a wiping device (not shown) that wipes the nozzle surfaces (bottom surfaces) of the ink heads 61A to 61E.

[0027] As shown in Figure 3, the flushing stage 90 is configured as a box shape that is rectangular in plan view and has an open top. Inside the flushing stage 90, there is a sponge 91 for absorbing ink. A suction pump (not shown) for sucking up ink is connected to the bottom of the flushing stage 90.

[0028] The lighting device 100 illuminates the inside of the housing 15 so that the state of the recording medium 5 on the platen 20 and the state of the flashing stage 90 can be easily seen. As shown in Figure 3, the lighting device 100 includes an ultraviolet light source 110 that emits light including ultraviolet light to make the foam-suppressing ink visible, a white light source 120 that emits white light, an operating circuit 130 (see Figure 6) that turns on the ultraviolet light source 110 and the white light source 120, and a support member 140 that supports the ultraviolet light source 110 and the white light source 120. The operating circuit 130 is configured to selectively turn on either the ultraviolet light source 110 or the white light source 120.

[0029] The ultraviolet light source 110 irradiates light in a wavelength range that makes the foam-suppressing ink visible. In this case, the ultraviolet light source 110 irradiates the platen 20 and the flashing stage 90 with light that includes ultraviolet light. The foam-suppressing ink is colorless and transparent, and it is difficult to see its state even when illuminated with visible light. However, it is known that when irradiated with ultraviolet light, some of the reflected light from the foam-suppressing ink becomes colored light, making it easier to see.

[0030] Figure 4 is a graph showing the intensity distribution of light generated by the ultraviolet light source 110. The horizontal axis of Figure 4 represents the wavelength of light (nm). The vertical axis of Figure 4 represents the intensity of light. "Ultraviolet light" refers to light with a wavelength of 10 nm or more and less than 400 nm. As shown in Figure 4, the ultraviolet light source 110 emits light that includes ultraviolet light (light of 10 nm or more and less than 400 nm) and whose peak wavelength Lp is within the visible light region (400 nm or more). The peak wavelength Lp is the wavelength with the highest intensity (the most light emitted). Most of the light emitted by the ultraviolet light source 110 is visible light, and a portion (for example, between one-quarter and one-third) is ultraviolet light. However, the intensity distribution of light generated by the ultraviolet light source 110 is not particularly limited as long as the foam-suppressing ink remains visible.

[0031] As shown in Figure 3 (see also Figure 6), in this embodiment, the ultraviolet light source 110 is composed of a plurality of ultraviolet emitting LEDs 111. The white light source 120 is also composed of a plurality of white light emitting LEDs 121. In this embodiment, one ultraviolet emitting LED 111 and one white light emitting LED 121 are mounted on one substrate B1. The lighting device 100 comprises a plurality of substrates B1. Each substrate B1 is configured as a flat plate and is arranged in the scanning direction Y (see also Figure 5). However, the configuration of the ultraviolet light source 110 and the white light source 120 is not limited to the above. For example, the ultraviolet light source 110 and the white light source 120 may be mounted on separate substrates.

[0032] The support member 140 is positioned above the platen 20 and the flashing stage 90 and supports a plurality of substrates B1 (ultraviolet light source 110 and white light source 120). The support member 140 extends above the platen 20 and the flashing stage 90. The support member 140 is positioned so as to overlap with the rear portion of the platen 20 with respect to the transport direction X. Here, the support member 140 is positioned in front of the grid roller 41 and the pinch roller 42. Figure 5 is a partially broken perspective view of the printer 10 cut through a vertical plane passing through the support member 140. As shown in Figure 5, the support member 140 comprises a light source support section 141 that supports a plurality of substrates B1 (ultraviolet light source 110 and white light source 120), a plurality of first windows 142 provided below the light source support section 141, and a plurality of second windows 143 provided below the light source support section 141 and aligned with the plurality of first windows 142 in the front-rear direction.

[0033] Multiple first windows 142 and multiple second windows 143 are provided on the bottom surface 140D of the support member 140. The bottom surface 140D extends in the transport direction X and the scanning direction Y. The support member 140 has a front surface 140F that extends upward from the front end of the bottom surface 140D. The light source support part 141 extends rearward from the upper end of the front surface 140F. The support member 140 is formed here by bending a metal plate.

[0034] The light source support section 141 extends in the transport direction X and the scanning direction Y. The light source support section 141 supports a plurality of substrates B1 aligned in the scanning direction Y. The ultraviolet light source 110 and the white light source 120 mounted on the plurality of substrates B1 emit light downwards.

[0035] Multiple first windows 142 are located directly below the light source support 141. In a plan view, the light source support 141 and the multiple first windows 142 overlap. The multiple first windows 142 are arranged in a line in the scanning direction Y. Each first window 142 penetrates the bottom surface 140D in the vertical direction. Note that each first window 142 may be a single elongated hole extending in the scanning direction Y.

[0036] The multiple second windows 143 are positioned behind the multiple first windows 142. However, the multiple second windows 143 may be positioned in front of the multiple first windows 142. The light source support 141 and the multiple second windows 143 are positioned offset in the transport direction X. The multiple second windows 143 are also positioned side by side in the scanning direction Y. Each second window 143 penetrates the bottom surface 140D in the vertical direction. Note that the second window 143 may also be a single elongated hole extending in the scanning direction Y.

[0037] The support member 140 includes diffusers 144 provided in a plurality of second windows 143. The diffusers 144 are configured to transmit light while diffusing it. The diffusers 144 are translucent plates with a rough surface texture so that light is refracted in multiple directions as it passes through them. However, the configuration of the diffusers 144 is not particularly limited. The light transmitted through the diffusers 144 is widely diffused into the internal space of the housing 15, illuminating the platen 20 and the flashing stage 90.

[0038] Figure 6 is a circuit diagram of the operating circuit 130. As shown in Figure 6, the operating circuit 130 includes a power supply 131, a first power line 132 connected to the ultraviolet light source 110, a second power line 133 connected to the white light source 120, and a switching unit 134 that selectively connects the power supply 131 to either the first power line 132 or the second power line 133. The switching unit 134 includes a changeover switch 134a that allows the user to select one of the following positions: a first position P1 in which the power supply 131 is connected to the first power line 132 and the ultraviolet light source 110 is turned on, a second position P2 in which the power supply 131 is connected to the second power line 133 and the white light source 120 is turned on, and a third position P3 in which the first power line 132 and the second power line 133 are disconnected from the power supply 131 and the ultraviolet light source 110 and the white light source 120 are turned off.

[0039] As shown in Figure 6, the operating circuit 130 includes three or more resistors 135 arranged in series on the first power line 132. In this embodiment, the operating circuit 130 includes three resistors 135A, 135B, and 135C arranged in series on the first power line 132. Here, the resistance values ​​of the three resistors 135A, 135B, and 135C are the same. However, some or all of the three resistors 135A, 135B, and 135C may have different resistance values. The three resistors 135A, 135B, and 135C arranged in series are connected in series with the ultraviolet light source 110 (more specifically, a plurality of ultraviolet irradiating LEDs 111). The plurality of ultraviolet irradiating LEDs 111, resistors 135A, 135B, and 135C are connected in series.

[0040] The total resistance on the first power line 132 is the sum of the individual resistance values ​​of the multiple UV-emitting LEDs 111, resistor 135A, resistor 135B, and resistor 135C. The current flowing through the first power line 132 is the current obtained by dividing the voltage of the power supply 131 by the above total resistance. When the UV light source 110 is lit, the above current flows through each UV-emitting LED 111. The three resistors 135A, 135B, and 135C determine the current flowing through the UV light source 110. The three resistors 135A, 135B, and 135C determine the output of the UV light source 110. The three resistors 135A, 135B, and 135C limit the output of the UV light source 110. The number of resistors arranged in series on the first power line 132 is not particularly limited as long as there are three or more.

[0041] The output of the ultraviolet light source 110 is limited to an output that does not affect the user's eyes, etc., even when the front cover 17 is open. The output of the ultraviolet light source 110 is limited to an output that does not affect the user's eyes, etc., at least when the front cover 17 is closed. The operating circuit 130 may be configured so that the ultraviolet light source 110 does not light up unless the front cover 17 is closed.

[0042] As shown in FIG. 6, the operation circuit 130 includes two resistors 136A and 136B arranged in series on the second power line 133. The resistors 136A and 136B determine the output of the white light source 120 (the current flowing through the white light source 120).

[0043] The control device 150 (see FIG. 1) is connected to the take-up roll 35, the conveying device 40, the ink supply device 50, the ejection head 60, the head moving device 70, and the heating device 80, and controls their operations. The configuration of the control device 150 is not particularly limited. The control device 150 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited, but for example, an interface (I / F) for receiving print data and the like from an external device, a central processing unit (CPU: central processing unit) that executes instructions of a control program, a ROM (read only memory) that stores a program executed by the CPU, a RAM (random access memory) used as a working area for expanding the program, and a storage device such as a memory that stores programs and various data. A part of the functions of the control device 150 may be realized by, for example, an external computer connected to the printer 10.

[0044] In the present embodiment, the control device 150 controls each part and prints a test pattern on the recording medium 5 to check whether there are any nozzles with ejection defects for each nozzle row. The test pattern includes a pattern for checking whether there are any nozzles with ejection defects among the plurality of nozzles 62A that eject the foam suppression ink, and a pattern for each ink color for checking whether there are any nozzles with ejection defects among the plurality of nozzles 62B to 62E that eject the color ink. As the test pattern, various known patterns can be adopted without particular limitation.

[0045] [Examples of Use of the Lighting Device] Hereinafter, some examples of the situation where the lighting device 100 is used will be described. However, the timing of using the lighting device 100 is not particularly limited.

[0046] In a suitable example, the lighting device 100 may be used when checking the printing state with a test pattern. After printing a test pattern including a pattern of the anti-foaming ink and a pattern of the color ink (without heating), when the changeover switch 134a is switched to the first position P1, the pattern of the anti-foaming ink can be visually recognized by light including ultraviolet rays irradiated from the ultraviolet light source 110. When the changeover switch 134a is switched to the second position P2, the pattern of the color ink can be visually recognized by white light irradiated from the white light source 120. Although it is also possible to visually recognize the pattern of the color ink by the light irradiated from the ultraviolet light source 110, since there are effects such as a change in color tone, etc., the pattern of the color ink is preferably visually recognized under white light.

[0047] In another suitable example, it is possible to visually recognize whether the flushing stage 90 is soiled with ink by the light of the lighting device 100. When the changeover switch 134a is switched to the first position P1, it is possible to visually recognize whether the anti-foaming ink adheres to the flushing stage 90 by light including ultraviolet rays irradiated from the ultraviolet light source 110. When the changeover switch 134a is switched to the second position P2, it is possible to visually recognize whether the color ink adheres to the flushing stage 90 by white light irradiated from the white light source 120.

[0048] [Operational Effects of the Embodiment] Hereinafter, the operational effects that can be achieved by the printer 10 according to the present embodiment will be described.

[0049] The printer 10 according to this embodiment includes a platen 20 that supports a heat-foaming recording medium 5, an ink cartridge 51A that stores a colorless, transparent foam-suppressing ink that suppresses foaming of the recording medium 5, a discharge head 60 positioned above the platen 20 and having a group of nozzles 62A that discharges the foam-suppressing ink stored in the ink cartridge 51A downward, a heating device 80 that heats the recording medium 5, an ultraviolet light source 110 positioned above the platen 20 that irradiates light including ultraviolet light to make the foam-suppressing ink visible, and an operating circuit 130 that lights up the ultraviolet light source 110. The operating circuit 130 includes a power supply 131, a first power line 132 that connects the power supply 131 and the ultraviolet light source 110, and three or more resistors 135 arranged in series on the first power line 132.

[0050] In this printer 10, three or more resistors 135 are arranged in series on a first power line 132 connecting a power supply 131 and an ultraviolet light source 110. The three or more resistors 135 arranged in series on the first power line 132 determine the current flowing through the ultraviolet light source 110 and limit the output of the ultraviolet light source 110. Furthermore, because there are three or more resistors 135, even if one of the resistors 135 on the first power line 132 is short-circuited, the increase in the current flowing through the ultraviolet light source 110 can be kept to a minimum. In this embodiment, even if one of the resistors 135A, 135B, and 135C on the first power line 132 is short-circuited, the current flowing through the ultraviolet light source 110 will increase by at most about 1.5 times (assuming the resistance value of the ultraviolet light source 110 is sufficiently smaller than the resistance values ​​of resistors 135A, 135B, and 135C). However, if there are two resistors on the first power line 132, for example, if one resistor is short-circuited, the current flowing to the ultraviolet light source 110 can be increased to approximately twice the original amount. Thus, according to the printer 10 of this embodiment, the intensity of ultraviolet light emitted by the ultraviolet light source 110 can be more reliably limited, even in the event of a malfunction.

[0051] Even if a short circuit occurs in one resistor 135, the output of the ultraviolet light source 110 is set to an output that does not affect the user's eyes. Here, for example, if we consider the case where there are two resistors on the first power line 132, if we want the output of the ultraviolet light source 110 to be an output that does not affect the user's eyes even when one resistor is short-circuited, the output of the ultraviolet light source 110 when it is not malfunctioning will be more limited than in this embodiment, and the brightness of the ultraviolet light source 110 will be dimmer. By increasing the number of resistors on the first power line 132, the brightness of the ultraviolet light source 110 can be increased within an acceptable range.

[0052] In this embodiment, the ultraviolet light source 110 emits light that includes ultraviolet light and whose peak wavelength Lp is within the visible light region. With this configuration, the amount of ultraviolet light can be reduced relative to the output of the ultraviolet light source 110. It is also possible to reduce the current flowing through the ultraviolet light source 110 by increasing the resistance values ​​of three or more resistors 135 and thereby limiting the output of the ultraviolet light source 110, but in practice, if the current flowing through the ultraviolet light source 110 is reduced too much, the operation of the ultraviolet light source 110 tends to become unstable. In contrast, in this embodiment, it is easy to suppress the amount of ultraviolet light emitted from the ultraviolet light source 110 without excessively limiting the output of the ultraviolet light source 110.

[0053] The printer 10 according to this embodiment includes a flushing stage 90 positioned alongside the platen 20 to receive the foam-suppressing ink ejected by the ejection head 60. The ultraviolet light source 110 also irradiates the flushing stage 90 with light including ultraviolet rays. With this configuration, it is possible to visually confirm whether or not foam-suppressing ink is adhering to the flushing stage 90.

[0054] The printer 10 according to this embodiment includes a support member 140 positioned above the platen 20. The support member 140 includes a light source support section 141 that supports the ultraviolet light source 110, a first window 142 provided below the light source support section 141, a second window 143 provided below the light source support section 141 and aligned with the first window 142 in the front-to-back direction, and a diffuser plate 144 provided in the second window 143 that transmits light while diffusing it. With this configuration, a relatively large amount of ultraviolet light can be irradiated directly below the first window 142, improving the visibility of the foam-suppressing ink on the platen 20 and the flashing stage 90. Furthermore, the light diffused by the diffuser plate 144 and irradiated from the second window 143 makes it possible to see the foam-suppressing ink over a wide area.

[0055] The printer 10 according to this embodiment has a front opening 16 on its front surface and comprises a housing 15 that houses at least a portion of the platen 20, an ejection head 60, and an ultraviolet light source 110. The printer 10 further comprises a front cover 17 provided in the front opening 16 and that transmits light emitted by the ultraviolet light source 110. With this configuration, the foam-suppressing ink inside the housing 15 can be visually inspected through the front opening 16 and the front cover 17.

[0056] The printer 10 according to this embodiment further includes ink cartridges 51B to 51E for storing color ink, and a white light source 120 positioned above the platen 20 and emitting white light. The ejection head 60 includes nozzle groups 62B to 62E for ejecting the color ink stored in the ink cartridges 51B to 51E downwards. The operating circuit 130 includes a second power line 133 connected to the white light source 120, and a switching unit 134 for selectively connecting the power supply 131 to either the first power line 132 or the second power line 133, and is configured to selectively light up either the ultraviolet light source 110 or the white light source 120. With this configuration, the ultraviolet light source 110 is turned on when the foam-suppressing ink is visible, and the white light source 120 is turned on when the color ink is visible, so both the foam-suppressing ink and the color ink can be clearly seen.

[0057] [Other Embodiments] A preferred embodiment of the present invention has been described above. However, the present invention can also be implemented by other embodiments.

[0058] For example, in the embodiment described above, the ultraviolet light source 110 was composed of multiple ultraviolet irradiating LEDs 111. However, the ultraviolet light source 110 may have only one light-emitting element. The same applies to the white light source 120.

[0059] In the embodiment described above, the lighting device 100 included a support member 140 having a first window 142, a second window 143, and a diffuser plate 144, but the configuration of the member supporting the ultraviolet light source 110 is not limited. The support member 140 may, for example, not include a window or a diffuser plate. The support member 140 may, for example, include a first window 142 and a diffuser plate provided in the first window 142, but may not include a second window 143.

[0060] In the embodiment described above, the lighting device 100 included an ultraviolet light source 110 and a white light source 120. However, the lighting device 100 may include only the ultraviolet light source 110 and not include the white light source 120.

[0061] The configuration of the printer 10 is not particularly limited. For example, the printer 10 may be a flatbed type printer equipped with a flatbed on which a heat-expandable recording medium is placed. The printer 10 does not necessarily have to be equipped with a flushing stage 90. Unless otherwise specified, the embodiments described above do not limit the present invention.

[0062] 5 Recording medium 10 Inkjet printer 15 Housing 16 Front opening 17 Front cover 20 Platen (support base) 51A Ink cartridge (first storage container) 51B-51E Ink cartridge (second storage container) 60 Ejection head 62A Nozzle (first nozzle group) 62B-62E Nozzle (second nozzle group) 80 Heating device 90 Flashing stage 100 Lighting device 110 Ultraviolet light source 120 White light source 130 Operating circuit 131 Power supply 132 First power line 133 Second power line 134 Switching unit 135 Resistor 140 Support member 141 Light source support unit 142 First window 143 Second window 144 Diffuser plate

Claims

1. An inkjet printer comprising: a support base for supporting a heat-expandable recording medium; a first storage container for storing a colorless, transparent foam inhibitor for suppressing foaming of the recording medium; a discharge head positioned above the support base, having a first group of nozzles for discharging the foam inhibitor stored in the first storage container downwards; a heating device for heating the recording medium; an ultraviolet light source positioned above the support base for irradiating light containing ultraviolet light that makes the foam inhibitor visible; and an operating circuit for turning on the ultraviolet light source, wherein the operating circuit comprises: a power supply; a first power line connecting the power supply and the ultraviolet light source; and three or more resistors arranged in series on the first power line.

2. The inkjet printer according to claim 1, wherein the ultraviolet light source emits light that includes ultraviolet light and whose peak wavelength is in the visible light region.

3. The inkjet printer according to claim 1 or 2, further comprising a flushing stage positioned alongside the support base and receiving the foaming inhibitor discharged by the discharge head, wherein the ultraviolet light source also irradiates the flushing stage with light including the ultraviolet light.

4. The inkjet printer according to claim 3, further comprising: a light source support section for supporting the ultraviolet light source; a first window provided below the light source support section; a second window provided below the light source support section and aligned with the first window in the front-to-back direction; and a diffuser plate provided in the second window that transmits light while diffusing it, and further comprising a support member positioned above the support base.

5. An inkjet printer according to any one of claims 1 to 4, further comprising: a housing having a front opening on the front and housing at least a part of the support base, the ejection head, and the ultraviolet light source; and a front cover provided in the front opening and transmitting light emitted by the ultraviolet light source.

6. An inkjet printer according to any one of claims 1 to 5, further comprising: a second storage container for storing color ink; a white light source disposed above the support base and emitting white light; the ejection head comprising a second nozzle group for ejecting the color ink stored in the second storage container downward; and the operating circuit comprising: a second power line connected to the white light source; and a switching unit for selectively connecting the power to the first power line or the second power line, configured to selectively light up the ultraviolet light source or the white light source.

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