Image recording device

Abstract

To provide an image recording device capable of improving detection accuracy by an optical sensor, and preventing an ultraviolet ray curing an ink from leaking to the outside of a machine.SOLUTION: An image recording device 1 is equipped with a head 121 that discharges a photo-curing liquid to a discharge medium W, a curing device 123 that irradiates curing light for curing the liquid, a distance measuring device 140 that has a first light emitting portion 141 that emits distance measuring light for measuring a distance to the discharged medium and a first light-receiving portion 142 receiving the distance measuring light, and a housing 2 that stores the head, the curing device, and the distance measuring device and has a window 11 through which the inside can be visually recognized. The window is provided with a first filter 20 for limiting the transmission of the curing light as compared with visible light, and the first light-receiving portion is provided with a second filter 21 limiting the transmission of the visible light as compared with the distance measuring light.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image recording apparatus such as an inkjet printer, for example.

Background Art

[0002] Conventionally, as a printing apparatus that discharges ultraviolet curable ink onto the surface of a three-dimensional solid object to print an image, the printing apparatus disclosed in Patent Document 1 is known. The printing apparatus of this Patent Document 1 includes a configuration for detecting the height of an object to be printed placed on a table. Specifically, the printing apparatus includes a lifting mechanism that moves the table up and down, a movable plate member that contacts the object to be printed that has risen together with the table, and an optical sensor such as a photomicrosensor that detects the displacement of the plate member.

[0003] Thereby, when the table on which the object to be printed is placed is raised and the object to be printed is still raised after contacting the plate member, the displacement of the plate member is detected by the optical sensor, so that it can be determined that the object to be printed has reached a predetermined height. Further, this printing apparatus includes a case that houses the above-described table and the like, and a front cover that is provided so as to be openable and closable with respect to the opening of the case, and a window for visually recognizing the printing state inside the case is provided on the front cover.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case of the printing apparatus of Patent Document 1, external light enters the case through the window. Then, since the printing apparatus detects the displacement of the plate member based on the amount of received light detected by the optical sensor, visible light entering as disturbance may affect the detection accuracy. In addition, ultraviolet rays irradiated to cure the ink may leak to the outside through the window.

[0006] The present invention has been made to solve such problems, and an object thereof is to provide an image recording apparatus capable of improving the detection accuracy by an optical sensor and preventing leakage of ultraviolet rays for curing ink to the outside of the apparatus.

Means for Solving the Problems

[0007] The image recording apparatus according to the present invention includes a head that discharges a photocurable liquid onto a medium to be discharged, a curing device that irradiates curing light for curing the liquid, a first light emitting unit that emits distance measuring light for measuring the distance to the medium to be discharged, and a distance measuring device having a first light receiving unit that receives the distance measuring light, and a housing that houses the head, the curing device, and the distance measuring device and has a window through which the inside can be visually recognized. A first filter that restricts transmission of the curing light compared to visible light is provided on the window, and a second filter that restricts transmission of visible light compared to the distance measuring light is provided on the first light receiving unit.

[0008] With such a configuration, since the first filter restricts the transmission of the curing light, leakage of the curing light to the outside of the window can be prevented. Further, even if visible light enters the housing through the window, since the second filter restricts the transmission of this visible light, it is possible to prevent the visible light from entering as a disturbance in the first light receiving unit, and improve the distance measurement accuracy.

Effects of the Invention

[0009] According to the present invention, it is possible to provide an image recording apparatus capable of improving the detection accuracy by an optical sensor and preventing leakage of ultraviolet rays for curing ink to the outside of the apparatus.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0011] The image recording apparatus according to an embodiment of the present invention will be described with reference to the drawings. Note that the image recording apparatus described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiments, and additions, deletions, and changes are possible without departing from the spirit of the present invention.

[0012] <Regarding the external configuration> FIG. 1 is a perspective view showing an image recording apparatus 1 according to an embodiment. In the concept of directions in this specification, the directions orthogonal to each other as shown in FIG. 1 are the vertical direction, the horizontal direction, and the front-rear direction. Also, the horizontal direction is the main scanning direction Ds, and the front-rear direction is the sub-scanning direction (corresponding to the conveyance direction of the ejected medium W) Df that is orthogonal to the main scanning direction Ds.

[0013] As shown in FIG. 1, the image recording apparatus 1 of the present embodiment includes a housing 2, operation keys 3, a display unit 4, a tray 5, a stage 6, a carriage 7, and an ink tank 8.

[0014] Of these, the housing 2 is formed, for example, in a box shape, has a front opening 2a for supplying the medium W to be discharged on its front surface, and has an upper cover 10 that can be opened and closed on its upper part. This upper cover 10 can be opened by rotating the front part upward with the rear part as a pivot point. When the upper cover 10 is opened, the inside of the housing 2 is exposed through the upper opening 2b of the housing 2. Further, a window 11 through which the inside of the housing 2 can be visually recognized is provided in the upper cover 10. That is, even when the upper cover 10 is closed, the user can visually recognize the inside of the housing 2 through the window 11. Such a housing 2 houses a discharge head 121, a curing device 123, a distance measuring device 140, etc., which will be described later.

[0015] An operation key 3 is provided at the right front part of the housing 2 to receive operation inputs by the user. A display unit 4 is provided behind the operation key 3 to display predetermined information. Further, when the display unit 4 is configured as a touch panel, the display unit 4 can display information and also receive operation inputs by the user.

[0016] A tray 5 is provided in front of the front opening 2a of the housing 2, and a stage 6 that forms a support for supporting the medium W to be discharged is provided above the tray 5. The tray 5 supports the stage 6 from below, and together with the stage 6, it is movable in the front-rear direction between a position in front of the front opening 2a and a position inside the housing 2 from the front opening 2a by a conveying device 136 (see FIG. 2). The stage 6 has a flat plate shape and is movable in the vertical direction with respect to the stage 6 by an approaching / separating device 133 (see FIG. 2) while supporting the medium W to be discharged.

[0017] The carriage 7 is provided below the upper opening 2b within the housing 2. The carriage 7 is configured to be reciprocally movable along the main scanning direction Ds by a scanning device 130 (see FIG. 2). Mounted on this carriage 7, in this order from the left, are a discharge device 120, a curing device 123, and a distance measuring device 140. The discharge device 120 discharges ultraviolet curable inks of various colors such as cyan (C), magenta (M), yellow (Y), black (K), white (W), and transparent. The curing device 123 irradiates ultraviolet rays toward the ink that has landed on the discharged medium W. Also, the distance measuring device 140 measures the distance to the opposing object. Details of each of these devices will be described separately later.

[0018] The ink tanks 8 store the above-described ultraviolet curable inks of various colors individually. Each ink tank 8 is connected to the discharge device 120 through an ink tube and supplies each ink to the discharge device 120.

[0019] <Regarding the functional configuration> FIG. 2 is a block diagram of the image recording apparatus 1. As shown in this FIG. 2, the image recording apparatus 1 includes a control device 100 corresponding to a computer having an MPU, a RAM, a ROM, etc., and a storage device 110 composed of a flash memory or a hard disk drive, etc. Then, based on the control program stored in the storage device 110, the control device 100 controls the operations of each device included in the image recording apparatus 1. The image recording apparatus 1 includes, as these devices, a discharge device 120, a curing device 123, a scanning device 130, an approaching / separating device 133, a conveyance device 136, a distance measuring device 140, and a medium detection device 143, etc.

[0020] The ejection device 120 includes an ejection head 121 that ejects ultraviolet curable ink (hereinafter simply referred to as "ink"), which is an example of a photocurable liquid, toward the ejected medium W (that is, in the direction of the stage 6), and a head driver 122. A plurality of dedicated nozzles for each color of ink are provided on the lower surface (nozzle surface) of the ejection head 121, and an actuator driven by electricity is provided for each nozzle in the ejection head 121. The head driver 122 is composed of an IC chip or the like, operates according to a control signal from the control device 100, and drives the actuator for each nozzle. The actuator is driven by power supply from the head driver 122, applies ejection pressure to the ink supplied from the ink tank 8 to the ejection head 121, and the ink to which pressure is applied is ejected from the nozzle and ejected onto the ejected medium W.

[0021] As shown in FIG. 1, the image recording apparatus 1 according to the present embodiment includes two ejection heads 121 (see also FIG. 3(A)). One of the ejection heads 121 ejects four colors of ink of CMYK, and the other ejection head 121 ejects inks of W and transparent. However, the number of ejection heads 121 is not limited to two, and may be one, or three or more.

[0022] The curing device 123 includes an ultraviolet lamp 124 that emits ultraviolet rays, which is an example of curing light for curing the above ink, and an irradiation driver 125 that drives the ultraviolet lamp 124. The ultraviolet lamp 124 has a plurality of light emitting diode chips that emit ultraviolet rays, and irradiates the ink landed on the ejected medium W with ultraviolet rays. The irradiation driver 125 is composed of an IC chip or the like, operates according to a control signal from the control device 100, and drives the ultraviolet lamp 124. For example, for each light emitting diode chip of the ultraviolet lamp 124, not only the switching between lighting and extinguishing but also the light amount during lighting can be individually adjusted.

[0023] As shown in FIG. 1, in the image recording apparatus 1 according to the present embodiment, the curing device 123 includes two ultraviolet lamps 124 (see also FIG. 3(A)). One ultraviolet lamp 124 is located on the side corresponding to one discharge head 121, and the other ultraviolet lamp 124 is located on the side corresponding to the other discharge head 121. However, the number of ultraviolet lamps 124 is not limited to two, and may be one for all the discharge heads 121, or may be three or more.

[0024] The scanning device 130 includes a carriage motor 131 which is an electric motor, and a motor driver 132 that drives the carriage motor 131. In addition, the scanning device 130 also includes a pulley connected to the rotation shaft of the carriage motor 131, an endless belt wound around the pulley and connected to the carriage 7, and a guide rail that supports the carriage 7. Then, based on a control signal from the control device 100, when the carriage motor 131 is driven by the motor driver 132, the pulley rotates and the endless belt rotates, and accordingly, the carriage 7 reciprocates in the left - right direction along the guide rail.

[0025] The approaching - separating device 133 includes an approaching - separating motor 134 which is an electric motor, and a motor driver 135 that drives the approaching - separating motor 134. In addition, the approaching - separating device 133 also includes a cam connected to the rotation shaft of the approaching - separating motor 134, and a guide that supports the vertical movement of the stage 6. Then, based on a control signal from the control device 100, when the approaching - separating motor 134 is driven by the motor driver 135, the cam rotates and the stage 6 moves vertically along the guide. As a result, the stage 6 forming the support of the medium W to be discharged moves in the directions of approaching and separating from the discharge head 121 located above, and can maintain an arbitrary position (height) within the range of its movement.

[0026] The conveying device 136 includes a conveying motor 137 which is an electric motor, and a motor driver 138 that drives the conveying motor 137. In addition, the conveying device 136 further includes a rack connected to the tray 5, a pinion that meshes with the rack and is connected to the rotating shaft of the conveying motor 137, and a rail for guiding the tray 5. Then, when the conveying motor 137 is driven by the motor driver 138 based on a control signal from the control device 100, the rack and the pinion operate, and the tray 5 (and the stage 6) moves in the front-rear direction along the rail.

[0027] The distance measuring device 140 is provided on the carriage 7 and is a sensor that measures the distance to the ejected medium W on the stage 6 located below when the carriage 7 moves and is positioned above the stage 6. This distance measuring device 140 includes a first light emitting unit 141 that emits distance measuring light which is light for measuring distance, and a first light receiving unit 142 that receives the distance measuring light reflected by the ejected medium W. For example, the first light emitting unit 141 has a laser diode chip as a light emitting element, and the first light receiving unit 142 is composed of a camera having an image sensor 142a and a lens 142b as light receiving elements (see also Fig. 3(C)). Then, when the first light emitting unit 141 emits the distance measuring light based on a control signal from the control device 100, this distance measuring light is reflected by the ejected medium W, and the reflected light is received by the first light receiving unit 142. The control device 100 acquires the distance to the ejected medium W based on the result received by the first light receiving unit 142. Such distance measuring processing by the control device 100 is executed by a distance measuring unit 101 realized by the control device 100 operating according to a control program stored in the storage device 110.

[0028] Here, in the case of the image recording apparatus 1 according to the present embodiment, the distance measuring light irradiated by the first light emitting unit 141 has the same wavelength as the curing light irradiated by the ultraviolet lamp 124 in the curing apparatus 123. Further, the wavelength is a relatively long wavelength among ultraviolet rays, specifically, a wavelength of 315 nm or more and less than 400 nm. However, the wavelengths of the distance measuring light and the curing light are not limited to this, and lights in different wavelength ranges may be used, and the wavelength range used may be outside the range of 315 nm or more and less than 400 nm.

[0029] In addition, the camera constituting the first light receiving unit 142 has a depth of field including the stage movable range from the position of the stage 6 (closest position) when the stage 6 is closest to the ejection head 121 by the approaching / separating device 133 to the position of the stage 6 (farthest position) when the stage 6 is farthest from the ejection head 121, within the focal length. In this way, it is desirable for the camera forming the first light receiving unit 142 to include the stage movable range and have as wide a depth of field as possible, but at least it should have a depth of field including at least a part of the stage movable range.

[0030] The medium detection device 143 is, for example, provided near the front opening 2a inside the housing 2, and is a sensor that detects the medium W to be ejected that is supported by the stage 6 and moves toward the front opening 2a together with the tray 5. The medium detection device 143 includes a second light emitting unit 144 that emits detection light and a second light receiving unit 145 that receives the detection light. As shown in FIG. 1, in the present embodiment, the second light emitting unit 144 is provided on the left side of the front opening 2a, and the second light receiving unit 145 is provided on the right side, and the two are arranged facing each other. Further, the second light emitting unit 144 has, for example, a laser diode chip as a light emitting element, and the second light receiving unit 145 has, for example, a photodiode chip as a light receiving element.

[0031] Further, the detection light emitted by the second light emitting unit 144 is set such that its optical axis passes near the upper surface (e.g., about 1 mm from the upper surface) of the stage 6 that moves back and forth together with the tray 5. Also, it is preferable to select the detection light that has high directivity and forms a constant diameter with substantially no spread between the second light emitting unit 144 and the second light receiving unit 145.

[0032] Such a medium detection device 143 intermittently emits detection light from the second light emitting unit 144 according to a control signal from the control device 100. And if the ejected medium W does not exist at a position where it blocks the optical axis of the detection light, the detection light is received by the second light receiving unit 145. On the other hand, when the ejected medium W exists at a position where it blocks the optical axis, the reception of the detection light by the second light receiving unit 145 is obstructed. Thus, whether the ejected medium W exists at a predetermined position crossing the optical axis of the detection light is detected based on whether the detection light is received by the second light receiving unit 145.

[0033] Note that the medium detection device 143 operates when the calibration unit 102 corrects the amount of the distance measurement light irradiated by the first light emitting unit 141 of the distance measurement device 140 onto the ejected medium W. Such a calibration process is executed by the calibration unit 102 that operates according to the control program stored in the storage device 110 by the control device 100. Details of the calibration process will be described separately later.

[0034] The shutter opening / closing device 150 is a mechanism that can open and close the light-emitting area of the first light-emitting unit 141 and the light-receiving area of the first light-receiving unit 140 of the distance measuring device 140. For example, it is composed of a shutter member 151 (see also Fig. 3(C)) and an actuator or the like. Then, based on a control signal from the control device 100, the actuator operates the shutter member 151, so that the above-described light-emitting area and light-receiving area can be switched between an open state where they are exposed and a closed state where they are blocked. The actuator can be composed of, for example, an electric motor, a pulley, and a belt, etc., but is not limited thereto, and other configurations can also be adopted. In addition, in this embodiment, as the shutter opening / closing device 150, an example of one that opens and closes the light-emitting area and the light-receiving area together (simultaneously) is illustrated, but it is not limited thereto, and a configuration in which the light-emitting area and the light-receiving area can be opened and closed independently of each other may be adopted.

[0035] Furthermore, the image recording device 1 includes an interface 111. The image recording device 1 can communicate with the outside through this interface 111, and for example, communicate with an external computer 200 such as a personal computer, and print an image on the ejection target medium W based on the image data received from the computer 200.

[0036] In the printing process, the above-described image recording device 1 reciprocates the carriage 7 in the left-right direction, ejects ink from the ejection head 121 at a predetermined timing, and further irradiates the ink landed on the ejection target medium W with ultraviolet rays from the ultraviolet lamp 124. Thereby, the ink on the ejection target medium W is cured, and an image is formed (printed) on the ejection target medium W.

[0037] Incidentally, in this image recording apparatus 1, the distance from the ejection head 121 to the stage 6 is relatively large. Therefore, not only two-dimensional shapes such as paper, but also on the surface of a three-dimensional ejection medium W having unevenness in the height direction (for example, a smartphone protective case, a golf ball, etc.), ink can be ejected to print an image. On the other hand, when printing on such a three-dimensional ejection medium W, by accurately grasping the height information of the printing surface of the ejection medium W and performing adjustments based on this height information, high image quality can be achieved. For example, it is conceivable to adjust the ink ejection timing according to the unevenness of the ejection medium W or adjust the height position of the stage 6 based on the height information. The image recording apparatus 1 according to the present embodiment includes the above-described distance measuring device 140 having the first light emitting unit 141 and the first light receiving unit 142 in order to acquire this height information.

[0038] Here, in order to realize accurate measurement by the distance measuring device 140, it is necessary that the first light receiving unit 142 can more accurately detect the distance measuring light emitted by the first light emitting unit 141 and reflected by the ejection medium W. However, even inside the housing 2, there is entry of external light. In particular, when visible light entering through the window 11 provided in the upper cover 10 of the housing 2 enters the first light receiving unit 142, this may cause interference and affect the detection accuracy of the distance measuring device 140. Also, it is desired to prevent ultraviolet rays irradiated from the ultraviolet lamp 124 for curing the ink from leaking to the outside through the window 11.

[0039] Therefore, the image recording apparatus 1 according to the present embodiment has a configuration for controlling the light inside the housing 2 using a filter or the like. Hereinafter, this configuration will be described.

[0040] <Regarding the filter etc.> As shown in FIG. 3(A), the carriage 7 according to the present embodiment is provided with two ejection heads 121, two ultraviolet lamps 124, and a set of distance measuring devices 140. Among these, the two ejection heads 121 are arranged side by side in the front-rear direction, the two ultraviolet lamps 124 are also arranged side by side in the front-rear direction, and the front ultraviolet lamp 124 is positioned corresponding to the right side of the front ejection head 121, and the rear ultraviolet lamp 124 is positioned corresponding to the right side of the rear ejection head 121. The distance measuring device 140 has a dimension that is long in the front-rear direction and is arranged on the right side of the two ultraviolet lamps 124.

[0041] Also, as shown in FIG. 1, the window 11 provided in the upper cover 10 of the housing 2 has a long dimension in the left-right direction and, as shown in FIG. 3(A), is positioned above the carriage 7 when viewed in plan. Therefore, visible light enters the housing 2 through this window 11. Note that FIG. 3(A) shows an example in which the window 11 is arranged so as to overlap the entire carriage 7, but it is not limited to this. The window 11 may be arranged offset in front of or behind the carriage 7, and more generally, it is positioned as forming an entry path for visible light that can reach the first light receiving part 142 of the distance measuring device 140.

[0042] As shown in FIG. 3(B), a first filter 20 is provided on the lower surface of the window 11. More specifically, the window 11 is composed of a flat plate member made of a material such as a transparent resin, and a sheet-like first filter 20 is attached to its lower surface. This first filter 20 has a function of selectively transmitting light, specifically, a function of restricting the transmission of curing light compared to visible light. Therefore, although the inside of the housing 2 can be visually recognized from the outside through the window 11, leakage of the curing light emitted from the ultraviolet lamp 124 to the outside through the window 11 is suppressed. In FIG. 3(B), visible light is indicated by a dashed arrow, and curing light is indicated by a solid arrow. Also, such a first filter 20 can be configured using a known optical filter having the same function. Further, the first filter 20 is not limited to the configuration shown in FIG. 3(B). For example, the first filter 20 may be provided on the upper surface of the window 11, may be provided so as to cover part or all of the window 11, or may be configured to be detachable from the window 11.

[0043] As shown in FIG. 3(C), the distance measuring device 140 has a configuration in which two first light receiving portions 142 arranged in the front-rear direction are provided between two first light emitting portions 141 provided at a distance from each other in the front-rear direction. The two first light emitting portions 141 include a light emitting element 141b having an optical axis 141a, and the optical axes 141a of each other have components in the direction facing each other. That is, the two first light emitting portions 141 have optical axes 141a that approach each other as they go in the light emitting direction. Thereby, the irradiation of the distance measuring light to the discharged medium W is not biased to either the front or the rear, and a shadow on the discharged medium W can be formed evenly in the front and rear, so that it is possible to improve the distance measuring accuracy by the triangulation method described later.

[0044] The two first light-receiving parts 142 in the center have an image sensor 142a and a lens 142b. The distance-measuring light emitted from the first light-emitting part 141 is reflected on the ejection target medium W and then enters the image sensor 142a through the lens 142b. Further, a second filter 21 is provided in the first light-receiving part 142. This second filter 21 has a function of selectively transmitting light, specifically, a function of restricting the transmission of visible light compared to the distance-measuring light. Therefore, as shown in the right diagram of Fig. 3(C), the distance-measuring light emitted from the first light-emitting part 141 passes through the second filter 21 and enters the first light-receiving part 142, while the visible light that has entered through, for example, the window 11 has its passage through the second filter 21 restricted. Thus, it is possible to prevent a decrease in distance-measuring accuracy due to the entry of visible light. In Fig. 3(C), the visible light is indicated by a dashed arrow, and the distance-measuring light is indicated by a solid arrow. Also, such a second filter 21 can be configured using a known optical filter having the same function.

[0045] Also, as shown in the left diagram of Fig. 3(C), the image recording apparatus 1 includes a shutter member 151. This shutter member 151 is a component of the shutter opening / closing device 150 described above and is opened and closed by an actuator driven based on a control signal from the control device 100. Specifically, when the shutter member 151 is in the closed state, as shown in the left diagram of Fig. 3(C), the light-emitting region of the first light-emitting part 141 and the light-receiving region of the first light-receiving part 142 are blocked by the shutter member 151, and when in the open state, as shown in the right diagram of Fig. 3(C), these light-emitting and light-receiving regions are exposed. Therefore, when the distance-measuring process is not being performed, by keeping the shutter member 151 in the closed state, even if there are minute ink droplets (ink mist) remaining in the housing 2 and floating after being ejected from the ejection head 121, it is possible to prevent the first light-emitting part 141 and the first light-receiving part 142 from being contaminated by this ink mist.

[0046] <Other configurations> FIG. 4 is a schematic diagram for explaining the distance measurement process by the distance measurement device 140 according to the present embodiment. This distance measurement device 140 measures the distance to the ejected medium W using a so-called triangulation method based on the images obtained by the two first light receiving parts (cameras) 142. Since it is a known method, only the outline will be explained here, omitting the details. As shown in FIG. 4, let the distance between the image sensors 142a be B, the focal length be F, the distance to the object OB whose distance is to be measured be Z, and the parallax of the light incident on each image sensor 142a with respect to the object OB be D. At this time, triangle T1 with B as the base and Z as the height and triangle T2 with D as the base and F as the height are in a similar relationship. Therefore, the distance Z to the object OB can be obtained from the formula {Z = (B × F) / D} in the figure.

[0047] Note that the configuration and the measurement method of the distance measurement device 140 are not limited to those described above. For example, any other method may be adopted as long as it is a method of measuring the distance based on the light received by the sensor. In that case, any configuration suitable for this can be adopted.

[0048] Next, with reference to FIG. 5, the calibration process for calibrating the light amount of the distance measurement light irradiated by the first light emitting part 141 of the distance measurement device 140 onto the ejected medium W will be explained. First, a general overview is given. This calibration process moves the ejected medium W downward away from the ejection head 121 in a state where the ejected medium W blocks the detection light, and based on the light reception amount of the distance measurement light at the first light receiving part 142 in a state where the ejected medium W no longer blocks the detection light, calibrates the light amount of the distance measurement light emitted by the first light emitting part 141. This calibration process is executed by the calibration part 102 of the control device 100. Also, by executing it before performing the distance measurement process, the distance measurement process can be performed with an appropriate light amount, and the improvement of the distance measurement accuracy can be achieved. Hereinafter, it will be explained more specifically.

[0049] As shown in FIG. 5, the image recording apparatus 1 supports the medium W to be ejected on the stage 6 and then conveys the stage 6 rearward toward the front opening 2a by the conveying device 136 (first step). At this time, the stage 6 is set at, for example, the uppermost position within the range where it can be raised and lowered. And the optical axis 144a of the detection light from the second light emitting part 144 of the medium detection device 143 is located in the vicinity directly above the stage 6. The detection light along this optical axis 144a is received by the second light receiving part 145 facing the second light emitting part 144 during the first step.

[0050] When the stage 6 is moved rearward in the first step, the medium W to be ejected approaches the optical axis 144a. And at some timing, the medium W to be ejected reaches a position where it crosses the optical axis 144a. At this time, since the detection light from the second light emitting part 144 is blocked by the medium W to be ejected, it is not received by the second light receiving part 145. The control device 100 determines the occurrence of the change from the detection state to the non-detection state in the second light receiving part 145 like this, and when it determines that the change has occurred, it stops the rearward movement of the stage 6 by the conveying device 136 (second step).

[0051] Next, the image recording apparatus 1 lowers the stage 6 together with the medium W to be ejected by the approaching / separating device 133 (third step). In this third step, the second light receiving part 145 is in the non-detection state, and the third step continues until it switches from the non-detection state to the detection state again. That is, in the third step, the stage 6 descends, while the position of the optical axis 144a of the detection light is fixed and does not fluctuate. Therefore, when the stage 6 is lowered, at some timing, the medium W to be ejected moves out of the position where it crosses the optical axis 144a, and the detection light is detected by the second light receiving part 145.

[0052] The control device 100 determines the occurrence of the switching from the non-detection state to the detection state in the second light-receiving unit 145. When it is determined that the switching has occurred, the control device 100 stops the lowering operation of the stage 6 by the contact / separation device 133 (fourth step). As a result, the control device 100 acquires height information regarding a predetermined location of the ejected medium W from the conveyance position and the lowered position of the stage 6. Then, the predetermined location of the ejected medium W is moved to the facing position of the distance measuring device 140 while maintaining the height, and the calibration of the light quantity of the distance measuring light is performed at that position.

[0053] That is, the distance measuring light is emitted from the first light-emitting unit 141 with a predetermined light quantity, and the light emission quantity by the first light-emitting unit 141 is corrected based on the received light quantity at the first light-receiving unit 142 at that time. More specifically, the height information acquired through the first to fourth steps is compared with the distance information measured by the distance measuring device 140 by emitting the distance measuring light from the first light-emitting unit 141 with respect to the predetermined location of the ejected medium W. Such comparison is performed while gradually changing the light emission quantity of the distance measuring light from the first light-emitting unit 141. Then, the light emission quantity when the difference value between the height information and the distance information is within a predetermined threshold value is selected, and the light emission quantity of the first light-emitting unit 141 when measuring the distance of the ejected medium W is corrected to this value.

[0054] Thereby, calibration of the first light-emitting unit 141 can be performed based on the height information of the ejected medium W which is the actual target for printing an image, so that more accurate distance measurement processing can be realized. Also, the environment where the image recording device 1 is installed may affect the light reception at the first light-receiving unit 142. Therefore, more accurate distance measurement processing can be performed by performing calibration according to changes in the installation environment. Note that the calibration method described above is an example and is not limited to this, and other calibration methods may be adopted.

[0055] In the above description, an example was shown in which the height information of the ejected medium W is acquired and calibration processing is performed based on this height information. However, height information other than the ejected medium W may be used. For example, as shown in FIG. 1, in the image recording apparatus 1 according to the present embodiment, a calibration member 30 is provided at a predetermined position on the stage 6. This calibration member 30 is, for example, in the shape of a block having a rectangular parallelepiped shape, and the upper surface forms a plane parallel to the stage 6. The height information of the upper surface of the calibration member 30 is stored in advance in a ROM or the like that the control device 100 has. The light amount may be calibrated based on the amount of received light when the calibration member 30 is irradiated with distance measuring light.

[0056] As described above, the image recording apparatus 1 according to the present embodiment includes the first filter 20 that restricts the transmission of curing light compared to visible light in the window 11, and the second filter 21 that restricts the transmission of visible light compared to distance measuring light in the first light receiving unit 142. Thereby, while preventing the curing light (typically ultraviolet light) from the curing device 123 from leaking to the outside through the window 11, the inside of the housing 2 can be visually recognized through the window 11, and the visible light entering from the window 11 can be prevented from entering the first light receiving unit 142, thereby preventing a decrease in distance measurement accuracy.

[0057] Note that, as described above, in the image recording apparatus 1, the distance measuring light and the curing light are light having the same wavelength. Thereby, not only the curing light but also the distance measuring light can be prevented from leaking to the outside through the window 11. Further, as the distance measuring light, light having a longer wavelength among ultraviolet rays, specifically, light having a wavelength of 315 nm or more and less than 400 nm is adopted. Thereby, small uneven shapes on the surface of the ejected medium W can be easily detected, and more accurate height information can be obtained, so that further high image quality of the image can be achieved.

Industrial Applicability

[0058] The present invention can be applied to an image recording apparatus.

Explanation of Signs

[0059] 1 Image recording apparatus 2 Housing 6 stages (substrate) 11 Windows 20 First filter 21 Second filter 30 Calibration member 100 Control device 121 Discharge head 123 Hardening device 133 Contact / separation device 140 Distance measuring device 141 First light emitting part 142 First light receiving part 143 Medium detection device 144 Second light emitting part 145 Second light receiving part 151 Shutter member W Discharged medium

Claims

1. A head that discharges a photocurable liquid onto a discharged medium, A curing device that irradiates a curing light for curing the liquid, A distance measuring device having a first light emitting unit that emits distance measuring light for measuring the distance to the discharged medium, and a first light receiving unit that receives the distance measuring light, A housing that houses the head, the curing device, and the distance measuring device and has a window through which the inside can be visually recognized, A support that supports the discharged medium, A contact / separation device that moves the support in a direction approaching and away from the head, and is provided with: A first filter that restricts the transmission of the curing light compared to visible light is provided on the window, A second filter that restricts the transmission of visible light compared to the distance measuring light is provided on the first light receiving unit, The first light receiving unit has a depth of field including a focal length in a range from the position of the support when the support is closest to the head by the contact / separation device to the position of the support when it is farthest, A camera having a depth of field including a focal length, Further provided are a medium detection device having a second light emitting unit that emits detection light of an optical axis passing above the support, and a second light receiving unit that receives the detection light emitted by the second light emitting unit, and a control device, The control device moves the discharged medium away from the head by the contact / separation device in a state where the discharged medium blocks the detection light on the optical axis, and based on the amount of received distance measuring light at the first light receiving unit in a state where the discharged medium no longer blocks the detection light, calibrates the light amount of the distance measuring light emitted by the first light emitting unit. An image recording device.

2. The distance measuring light irradiated by the first light emitting unit is light having the same wavelength as the curing light irradiated by the curing device. The image recording device according to claim 1.

3. The image recording apparatus according to claim 1 or 2, wherein the wavelength of the distance measuring light irradiated by the first light emitting unit is 315 nm or more and less than 400 nm.

4. The image recording apparatus according to any one of claims 1 to 3, further comprising a shutter that covers the light emitting region in the first light emitting unit in an openable and closable manner.

5. The image recording apparatus according to any one of claims 1 to 4, further comprising a shutter that covers the light receiving region in the first light receiving unit in an openable and closable manner.

6. The first light receiving unit includes a plurality of the cameras, The control device measures the distance to the ejected medium using triangulation based on images received by the plurality of cameras. The image recording apparatus according to claim 1.

7. The first light emitting unit has a plurality of light emitting elements including components in directions facing each other along the optical axis. The image recording apparatus according to any one of claims 1 to 5.

8. The support is provided with a calibration unit for calibrating the amount of light of the distance measuring light, The control device calibrates the amount of light of the distance measuring light emitted by the first light emitting unit based on the amount of light received by the first light receiving unit when the calibration unit is irradiated with the distance measuring light. The image recording apparatus according to any one of claims 1 to 5.

Images