Inkjet printer

Abstract

To provide a printer that can detect the height of a recording medium more surely.SOLUTION: A printer 10 comprises a light emitting part 30 and a light receiving part 40. Some or whole of detection light DL emitted by the light emitting part 30 is shielded by a recording medium 5, so that the height of the recording medium 5 is detected. A first slit 32a is formed in a first light shaft tube 32 provided on the light emitting part 30. The first slit depth L1 of the first slit 32a is longer than the first slit height t1. This can suppress the detection light DL passing through the first slit 32a from being diffused in a vertical direction, so that the height of the recording medium 5 can be detected more accurately.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to inkjet printers. [Background technology]

[0002] Conventionally, inkjet printers that print images on recording media of various thicknesses have been known. The vertical distance between the ink head that ejects ink and the recording medium must be a predetermined distance. Inkjet printers are known that are configured so that a mounting table on which the recording medium is placed can be moved vertically so that the distance between the ink head and the recording medium can be set to a predetermined distance even if the recording medium has a different thickness. The distance between the ink head and the recording medium is determined by the height of the thickest position of the recording medium (hereinafter, unless otherwise specified, referred to as the height of the recording medium). Therefore, before printing begins, the height of the recording medium must be set to a predetermined height.

[0003] For example, Patent Document 1 discloses an inkjet printer including a mounting table, a first moving mechanism for moving the mounting table in the vertical direction, a second moving mechanism for moving the mounting table in the front-rear direction, and a detection device for detecting whether the height of the recording medium is a predetermined height. The detection device includes a first light-emitting unit and a second light-emitting unit provided above the mounting table, and a first light-receiving unit and a second light-receiving unit for receiving light emitted in the left-right direction from the first light-emitting unit and the second light-emitting unit, respectively. The first light-emitting unit and the first light-receiving unit are disposed to face each other, and are positioned in the same vertical direction. The same applies to the positional relationship between the second light-emitting unit and the second light-receiving unit.

[0004] For example, if the height of the recording medium is higher than the light emitted from the first light emitter, when the table on which the recording medium is placed is moved forward and backward, the light emitted from the first light emitter is blocked by the recording medium, and the first light receiver does not receive the light. The detection device is configured to detect the recording medium when the first light receiver does not receive the light. Therefore, it is possible to detect whether the height of the recording medium is higher than a predetermined height depending on whether the first light receiver receives the light emitted from the first light emitter. The same applies to the second light emitter and the second light receiver.

[0005] In the inkjet printer, the height of the recording medium is set, for example, as follows. First, the stage on which the recording medium is placed is moved forward. When the light is blocked by the recording medium, the movement of the stage is stopped and the stage is moved downward until the light is no longer blocked by the recording medium. The stage is then moved forward again. When the light is blocked by the recording medium, the movement of the stage is stopped again and the stage is moved downward until the light is no longer blocked by the recording medium. The above operation is repeated until the entire recording medium is positioned forward of the first light-emitting unit and the second light-emitting unit. This sets the height of the recording medium to a predetermined height, and sets the distance between the ink head and the recording medium to a predetermined distance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2021-171924 A Summary of the Invention [Problem to be solved by the invention]

[0007] Here, depending on the light emitting elements included in the first light emitting unit and the second light emitting unit, the emitted light may spread in the vertical direction. If the light spreads in the vertical direction, the height of the recording medium when the detection device detects the recording medium varies.

[0008] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a printer that can more reliably detect the height of a recording medium placed on a placement table. [Means for solving the problem]

[0009] The recording medium is placed on a placement table, a placement table moving mechanism for moving the placement table, a light emitting unit arranged above the placement table and on one side of the placement table in the main scanning direction, and irradiating detection light toward the other side of the main scanning direction, and a light receiving unit arranged on the other side of the placement table in the main scanning direction, and receiving the detection light from the light emitting unit and outputting a signal corresponding to the amount of received light. The light emitting unit includes a light emitting device having a light emitting element that emits the detection light, and a detection light limiting unit adjacent to the light emitting device on the other side of the main scanning direction, and in which a first slit penetrating in the main scanning direction is formed. A first slit depth, which is the length of the first slit in the main scanning direction, is longer than the vertical length of a first slit opening provided at the other end of the first slit in the main scanning direction.

[0010] According to the inkjet printer of the present invention, the slit depth, which is the length of the first slit in the main scanning direction, is longer than the length of the first slit opening in the up-down direction. Therefore, the detection light emitted from the light-emitting element is prevented from diffusing in the up-down direction after passing through the first slit. That is, the detection light travels straight in the main scanning direction. This prevents the height of the recording medium from varying when it is detected that the detection light is partially or entirely blocked by the recording medium. Therefore, the height of the recording medium can be detected more reliably. Effect of the Invention

[0011] According to the present invention, it is possible to provide a printer that can more reliably detect the height of a recording medium placed on a placement table. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of a printer according to an embodiment; [Diagram 2] 1 is a front view of a printer with a front cover open according to an embodiment; [Diagram 3] FIG. 2 is a plan view of a printer with a front cover and a case removed according to an embodiment. [Figure 4] FIG. 2 is a front view showing a schematic configuration of a light-emitting section, a light-receiving section and their surroundings according to an embodiment. [Diagram 5] FIG. 2 is a perspective view of a light-emitting unit according to an embodiment. [Figure 6] 1 is a block diagram showing a configuration of a printer according to an embodiment; [Figure 7] 5 is a flowchart showing a procedure for detecting the height of a recording medium according to an embodiment. [Figure 8A] 5 is a cross-sectional view taken along the line AA in FIG. 4 when a recording medium is placed in front of the detection light. [Figure 8B] 5 is a cross-sectional view taken along the line AA in FIG. 4 when the detection light is blocked by a recording medium. [Figure 8C] 8C is a front view showing a schematic structure of the light emitting section, the light receiving section and their surroundings in FIG. 8B. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of a printer according to the present invention will be described with reference to the drawings. Note that the embodiment described here is, of course, not intended to limit the present invention in any particular way. Also, the same reference numerals are used for members and parts that perform the same functions, and duplicated descriptions will be omitted or simplified as appropriate.

[0014] FIG. 1 is a perspective view of a printer 10 according to the present embodiment. The printer 10 prints on a recording medium 5 (see FIG. 2). The printer 10 is an inkjet printer. In the following description, when the printer 10 is viewed from the front, the side away from the printer 10 is the front, and the side approaching the printer 10 is the rear. The terms left, right, top, and bottom refer to the left, right, top, and bottom of the printer 10 when viewed from the front. Also, the symbols F, Rr, L, R, U, and D in the drawings refer to the front, back, left, right, top, and bottom, respectively. Also, the symbol Y in the drawings indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. The symbol X indicates the sub-scanning direction. Here, the sub-scanning direction X is the front-rear direction, and is perpendicular to the main scanning direction Y in a plan view. The symbol Z indicates the up-down direction. The up-down direction Z is perpendicular to the main scanning direction Y in a front view. The sub-scanning direction X is an example of a first direction in the present invention. The main scanning direction Y is an example of the second direction in the present invention. The above direction is merely defined for the convenience of explanation, and does not limit the installation mode of the printer 10 or the present invention in any way.

[0015] The recording medium 5 used in this embodiment may be, for example, a flat sheet such as recording paper or transfer paper, or may be a three-dimensional object such as various cases such as mobile phone cases, small electronic devices, small parts such as key holders, photo frames, and pens, daily necessities, and accessories. The material forming the recording medium 5 may be paper such as plain paper and inkjet printing paper, as well as resins such as polyvinyl chloride, acrylic resin, polycarbonate, polystyrene, and acrylonitrile-butadiene-styrene (ABS) copolymer, metals such as aluminum and stainless steel, carbon, pottery, ceramic, glass, rubber, leather, wood, and the like. In the printer 10 of this embodiment, a three-dimensional object having an uneven shape is preferably used as the recording medium 5.

[0016] As shown in FIG. 1, the printer 10 includes a box-shaped housing 12. The housing 12 has an internal space 12S. The housing 12 includes a base member 13, a case 15, a front cover 23, and an operation panel 25. As shown in FIG. 2, the base member 13 includes a bottom wall 13A, a left side wall 13L, a right side wall 13R, and a support wall 13T. The bottom wall 13A extends in the main scanning direction Y and the sub-scanning direction X. The left side wall 13L extends in the up-down direction Z. The right side wall 13R extends in the up-down direction Z. The right side wall 13R is disposed to the right of the left side wall 13L. The left side wall 13L and the right side wall 13R are provided on the bottom wall 13A. The support wall 13T extends in the main scanning direction Y. The support wall 13T is supported by the bottom wall 13A. The case 15 is attached to the base member 13. An opening 28 is formed in the front of the case 15. The front cover 23 is provided so as to be able to open and close the opening 28 of the case 15. Here, the front cover 23 is supported by the case 15 so as to be rotatable about its rear end as an axis. By rotating the front cover 23 upward, the internal space 12S of the housing 12 is communicated with the external space. The internal space 12S is a space in which printing is performed on the recording medium 5 by the ink head 60 described later, and the height of the table 35 is determined by the light-emitting unit 30 and the light-receiving unit 40 described later. In this way, the internal space 12S is surrounded and formed by the case 15 and the front cover 23, so that dust and dirt from the external space are unlikely to enter the internal space 12S during printing, and light irradiated from the ultraviolet irradiation devices 51 and 52 described later is unlikely to leak into the external space.

[0017] 1, a window 23A is provided in the front and upper parts of the front cover 23. The window 23A is formed, for example, from a transparent acrylic plate. The window 23A is treated so that light from the external space (for example, ultraviolet light) does not reach the internal space 12S. The user can view the inside of the housing 12 from the window 23A.

[0018] The operation panel 25 is provided on the case 15. The operation panel 25 is provided on the right side of the top surface of the case 15. The operation panel 25 is a panel on which the user performs operations related to printing an image and setting (changing) the irradiation intensity of light irradiated from the ultraviolet irradiation devices 51, 52 (see FIG. 2). The operation panel 25 is provided with a display screen 25A on which information related to printing, such as the type of printing (e.g., whether or not there is a glossy finish), resolution, printing status, and the like, and input buttons 25B for setting information related to printing and the recording medium 5, and the like.

[0019] Next, the internal configuration of the printer 10 will be described. As shown in Fig. 2, the printer 10 includes a guide rail 18, a carriage 20, an ink head 60, ultraviolet irradiation devices 51 and 52, a table 35, a first table moving mechanism 37, a second table moving mechanism 38, a light emitting unit 30, a first mounting member 33, a light receiving unit 40, a second mounting member 43, and a control device 100. The guide rail 18 is disposed in a case 15. As shown in Fig. 3, the guide rail 18 is fixed to a support wall 13T of the base member 13 and extends in the main scanning direction Y. The table moving mechanism 36 includes a first table moving mechanism 37 and a second table moving mechanism 38.

[0020] As shown in FIG. 2, the carriage 20 is equipped with an ink head 60 and ultraviolet irradiation devices 51 and 52. The carriage 20 is slidably mounted on a guide rail 18. The printer 10 is equipped with a carriage movement mechanism 21. The carriage movement mechanism 21 is controlled by a control device 100. The carriage 20 reciprocates along the guide rail 18 in the main scanning direction Y by the carriage movement mechanism 21. The carriage movement mechanism 21 is controlled by the control device 100. The carriage movement mechanism 21 is equipped with a left pulley 21L, a right pulley 21R, a belt 21A wound around the left pulley 21L and the right pulley 21R, and a carriage motor 21B connected to the left pulley 21L. The belt 21A extends in the main scanning direction Y. The belt 21A is fixed to the upper part of the rear surface of the carriage 20. Here, the carriage motor 21B is driven to rotate the left pulley 21L, causing the belt 21A to run between the left pulley 21L and the right pulley 21R. This causes the carriage 20 to move in the main scanning direction Y. However, the carriage motor 21B may be connected to the right pulley 21R. As the carriage 20 moves in the main scanning direction Y, the ink head 60 and the ultraviolet ray irradiation devices 51 and 52 mounted on the carriage 20 also move in the main scanning direction Y.

[0021] As shown in FIG. 2, the carriage 20 is equipped with a plurality of ink heads 60. The ink heads 60 have nozzles (not shown) that eject photocurable ink (i.e., ink having photocurability, for example, ultraviolet curable ink) onto the recording medium 5 placed on the table 35. The ink heads 60 eject ink droplets from the nozzles toward the recording medium 5 to form ink dots on the recording medium 5. By arranging a large number of these dots, an image or the like is formed on the recording medium 5. Each of the ink heads 60 is connected to an ink cartridge 34 housed in the case 15 by a flexible ink tube (not shown). Each of the ink cartridges 34 stores photocurable ink. Here, three ink heads 60 are mounted on the carriage 20. However, the number of ink heads 60 is not limited to three.

[0022] The ultraviolet irradiation devices 51 and 52 irradiate light (typically ultraviolet light). The ultraviolet irradiation devices 51 and 52 irradiate light (here, ultraviolet light) toward the photocurable ink (here, ultraviolet curable ink) ejected onto the recording medium 5 to cure the photocurable ink. The irradiation intensity is controlled by the control device 100. The photocurable ink is cured by being irradiated with light from the ultraviolet irradiation devices 51 and 52, and an image is formed on the recording medium 5. As shown in FIG. 2, the ultraviolet irradiation devices 51 and 52 are disposed above a table 35, which will be described later. The ultraviolet irradiation device 51 is disposed to the left of the ink head 60. The ultraviolet irradiation device 52 is disposed to the right of the ink head 60.

[0023] As shown in FIG. 2, the printer 10 is a so-called flatbed type printer. The printer 10 includes a table 35 disposed below the carriage 20, and a table movement mechanism 36. The table 35 and the table movement mechanism 36 are provided in the internal space 12S. The table movement mechanism 36 is controlled by the control device 100. The table 35 is an example of a mounting table. The table movement mechanism 36 is an example of a mounting table movement mechanism. The recording medium 5 is placed on the table 35. The table 35 is disposed below the ink head 60. The table 35 is disposed to the right of the left side wall 13L and to the left of the right side wall 13R. The table movement mechanism 36 includes a first table movement mechanism 37 and a second table movement mechanism 38. The table 35 is configured to be movable in the up-down direction Z by the first table movement mechanism 37. The table 35 is configured to be movable in the sub-scanning direction X by the second table movement mechanism 38.

[0024] The first table moving mechanism 37 includes a height adjustment member 37a and a first motor 39A (see FIG. 6). The height adjustment member 37a is provided on the lower surface of the table 35. The height adjustment member 37a is connected to the first motor 39A. The first motor 39A is electrically connected to the control device 100 and is controlled by the control device 100. When the first motor 39A is driven, the height of the height adjustment member 37a changes, and the height of the table 35 is adjusted. That is, the first table moving mechanism 37 moves the table 35 in the up-down direction Z.

[0025] As shown in FIG. 3, the second table moving mechanism 38 includes slide rails 38a and 38b, a conveying member 38c, and a second motor 39B (see FIG. 6). The slide rails 38a and 38b extend in the sub-scanning direction X. The conveying member 38c is provided so as to be slidable relative to the slide rails 38a and 38b. Above the conveying member 38c, the table 35 is supported via a height adjustment member 37a (see FIG. 2). The second motor 39B is electrically connected to the control device 100 and is controlled by the control device 100. When the second motor 39B is driven, the conveying member 38c moves along the slide rails 38a and 38b. This causes the table 35 to move in the sub-scanning direction X. That is, the second table moving mechanism 38 moves the recording medium 5 placed on the table 35 in the sub-scanning direction X.

[0026] As shown in Fig. 4, the light-emitting unit 30 is provided on the right side wall 13R of the base member 13. The light-emitting unit 30 is provided forward of the support wall 13T. The light-emitting unit 30 includes a light emitter 31 and a first optical axis tube 32. The position of the light-emitting unit 30 in the vertical direction Z coincides with the position of the light-receiving unit 40 in the vertical direction Z.

[0027] The light emitter 31 is a device that includes a light emitting element 31a (see FIG. 5) and irradiates detection light DL from the light emitting element 31a toward the light receiving unit 40. In this embodiment, the detection light DL irradiated from the light emitting element 31a travels in the main scanning direction Y from right to left. The detection light DL is irradiated from the light emitting element 31a and travels while diffusing in the vertical direction. The detection light DL is not particularly limited, but may be, for example, light irradiated from an LED or laser light. In this embodiment, the light emitting element 31a is a light emitting diode, and the detection light DL is infrared light.

[0028] The first optical axis tube 32 is a diaphragm that suppresses the detection light DL from spreading in the sub-scanning direction X and the vertical direction Z. The first optical axis tube 32 is an example of a detection light limiting section in the present invention. The first optical axis tube 32 is adjacent to the left of the light emitter 31. As shown in FIG. 5, a first slit 32a is formed in the first optical axis tube 32. FIG. 5 is a perspective view showing the light emitter 30. The first slit 32a is formed to the left of the light emitting element 31a. The first slit 32a forms a first slit opening 32aa at the left end of the first optical axis tube 32. The first slit 32a is formed to have a length L1 in the main scanning direction Y (hereinafter referred to as "first slit depth"), a length w1 in the sub-scanning direction X (hereinafter referred to as "first slit width"), and a length t1 in the vertical direction Z (hereinafter referred to as "first slit height"). In this embodiment, the length of the first slit opening 32aa in the sub-scanning direction X is also w1, and the height of the first slit opening 32aa in the sub-scanning direction X is also t1. That is, the first slit 32a extends straight in the main scanning direction Y. The first slit depth L1 is longer than the first slit height t1. The first slit depth L1 is longer than the first slit width w1. The first slit width w1 is longer than the first slit height t1. That is, the first slit depth L1, the first slit width w1, and the first slit height t1 have a relationship of L1>w1>t1. The first optical axis tube 32 is provided with a first fixing portion 32b fixed to the first mounting member 33. In this embodiment, a bolt 32c is attached to the first fixing portion 32b. The light emitter 31, the first optical axis tube 32, and the first mounting member 33 are fixed together by the first fixing portion 32b. The first fixing portion 32b is provided below the first slit 32a. The first optical axis tube 32 has a hole 32d formed below the first slit 32a and extending in the left-right direction. The hole 32d is a hole whose outer diameter becomes smaller near the rear end of the first optical axis tube 32. Therefore, the hole 32d has a step at a position halfway in the main scanning direction Y. The head of the bolt 32c is placed in the step. There is no particular limitation on the method of fixing the first fixing portion 32b, but in this embodiment, the bolt 32c is inserted through the first optical axis tube 32 and the light emitter 31 and fastened to the first mounting member 33, thereby fixing the first optical axis tube 32, the light emitter 31, and the first mounting member 33.In this embodiment, the first optical axis tube 32 is made of a resin material. However, the material for forming the first optical axis tube 32 is not particularly limited.

[0029] The first mounting member 33 is a member to which the light emitter 31 and the first optical axis tube 32 are attached. The first mounting member 33 is fixed to the upper surface of the right side wall 13R (see FIG. 4). The first mounting member 33 is an example of a mounting member in the present invention. Although not shown, the first mounting member 33 has a screw hole for fastening the bolt 32c at a position aligned with the center of the hole 32d in the main scanning direction Y. The first optical axis tube 32 and the light emitter 31 are fixed to the first mounting member 33 by fastening the bolt 32c to the screw hole.

[0030] 4, the light receiving unit 40 is provided on the left side wall 13L of the base member 13. The light receiving unit 40 is disposed to face the light emitting unit 30 in the primary scanning direction Y. The light receiving unit 40 includes a light receiver 41 and a second optical axis tube 42.

[0031] The light receiver 41 is a device equipped with a light receiving element that receives the detection light DL. The appearance of the light receiver 41 is the same as that of the light emitter 31 shown in FIG. 5. The light receiver 41 is in the left-right direction opposite to that of the light emitter 31 shown in FIG. 5. The light receiver 41 is equipped with a light receiving element 41a (see FIG. 6). The light receiving element 41a outputs a signal to the control device 100 according to the amount of light received by the light receiving element. In this embodiment, the light receiving element is a photosensor. As shown in FIG. 4, when the detection light DL irradiated from the light emitter 31 of the light emitter 30 is at a position higher than the upper end of the recording medium 5, the detection light DL is not blocked by the recording medium 5, and the light receiver 41 receives the detection light DL. On the other hand, as shown in FIG. 8C, when the detection light DL is at a position lower than the upper end of the recording medium 5, a part or all of the detection light DL is blocked by the recording medium 5. Therefore, in Fig. 8C, the amount of detection light DL received by the photoreceiver 41 is reduced compared to that in Fig. 4. In this embodiment, as in Fig. 4, when the detection light DL is not blocked by the recording medium 5 and the photoreceiver 41 receives the detection light DL, the photoreceiver 41 is configured to turn a signal ON. Also, as in Fig. 8C, when part or all of the detection light DL is blocked by the recording medium 5 and the amount of detection light DL received by the photoreceiver 41 is reduced compared to that in Fig. 4, the photoreceiver 41 is configured to turn a signal OFF.

[0032] The second optical axis tube 42 shown in FIG. 4 is a diaphragm that limits the area through which the detection light DL passes so that the detection light DL travels toward the light receiving element 41a. The second optical axis tube 42 is an example of a light receiving side detection light limiting section. As shown in FIG. 4, the second optical axis tube 42 is adjacent to the light receiver 41 on the right side. In this embodiment, the second optical axis tube 42 is a member similar to the first optical axis tube 32. As shown in FIG. 5, the second optical axis tube 42 is formed with a second slit 42a. The first slit 32a is formed to the right of the light emitting element 31a. The second slit 42a is formed with a length L2 in the main scanning direction Y (hereinafter referred to as the "second slit depth"), a length w2 in the sub scanning direction X (hereinafter referred to as the "second slit width"), and a length t2 in the up-down direction Z (hereinafter referred to as the "second slit height"). In this embodiment, the length of the second slit opening 42aa in the sub-scanning direction X is also w1, and the height of the second slit opening 42aa in the sub-scanning direction X is also t2. That is, the second slit 42a extends straight in the main scanning direction Y. The second slit depth L2 is longer than the second slit height t2. The second slit depth L2 is longer than the second slit width w2. The second slit width w2 is longer than the second slit height t2. That is, the second slit depth L2, the second slit width w2, and the second slit height t2 have a relationship of L2>w2>t2. The second optical axis tube 42 is provided with a second fixing portion 42b fixed to the second mounting member 43, similar to the first optical axis tube 32. A bolt 42c is attached to the second fixing portion 42b. The second fixing portion 42b has the same configuration as the first fixing portion 32b, so a description thereof will be omitted here. Due to the second slit 42a formed in the second optical axis tube 42, the detection light DL traveling from the right side of the second optical axis tube 42 passes through the inside of the second slit 42a and travels toward the light receiving element 41a. Note that the first optical axis tube 32 and the second optical axis tube 42 do not have to be made of the same material. Also, the light receiving unit 40 does not have to include the second optical axis tube 42.

[0033] The second mounting member 43 is a member that fixes the optical receiver 41 and the second optical axis tube 42. The second mounting member 43 is fixed to the upper surface of the left side wall 13L. In this embodiment, the second mounting member 43 is a member similar to the first mounting member 33. However, the first mounting member 33 and the second mounting member 43 do not have to be similar members. The second mounting member 43 is an example of a mounting member in the present invention.

[0034] As shown in FIG. 6, the control device 100 is communicatively connected to the operation panel 25, the carriage motor 21B of the carriage movement mechanism 21, the first motor 39A of the first table movement mechanism 37, the second motor 39B of the second table movement mechanism 38, the light emitting element 31a, the light receiving element 41a, the ultraviolet ray irradiation devices 51 and 52, and the ink head 60. The control device 100 controls the operations of these elements. The control device 100 is typically a computer. The control device 100 includes, for example, an interface (I / F) for receiving print data and the like from an external device such as a host computer, a central processing unit (CPU) for executing instructions of a control program, a ROM for storing a program executed by the CPU, a RAM used as a working area for expanding the program, and a storage device such as a memory for storing the above-mentioned program and various data.

[0035] The control device 100 includes a movement control unit 101, a signal receiving unit 102, a determination unit 103, a descent control unit 104, an ascent control unit 105, a storage unit 106, and a print instruction unit 107. The functions of each unit of the control device 100 are realized by a program. This program is downloaded, for example, through the Internet. Note that this program may be read from a recording medium, such as a CD or a DVD. Also, the functions of each unit of the control device 100 may be realized by a processor and / or a circuit, etc.

[0036] The movement control unit 101 controls the second motor 39B of the second table moving mechanism 38 to move the table 35 in either direction in the sub-scanning direction X. The operation in which the movement control unit 101 controls the second motor 39B to move the table 35 is referred to as a table moving operation. The table moving operation is an example of a mounting base moving operation.

[0037] The signal receiving unit 102 is configured to receive a signal output by the light receiving element 41a. The determination unit 103 determines whether or not the detection light DL is partially or entirely blocked by the recording medium 5 based on the signal received by the signal receiving unit 102. In this embodiment, if the signal received by the signal receiving unit 102 is OFF, the determination unit 103 determines that the detection light DL is partially or entirely blocked by the recording medium 5. When the determination unit 103 determines that the detection light DL is partially or entirely blocked by the recording medium 5, the upper end of the recording medium 5 is disposed above the detection light DL. The operation of the determination unit 103 to determine whether or not the detection light DL is partially or entirely blocked by the recording medium 5 is referred to as a determination operation.

[0038] The lowering control unit 104 is configured to control the first motor 39A of the first table moving mechanism 37 to move the table 35 downward. When detecting the height of the recording medium 5, if the detection light DL is partially or entirely blocked by the recording medium 5, the lowering control unit 104 lowers the table 35 by a predetermined distance (hereinafter referred to as the "first distance"). The operation of lowering the table 35 by the first distance is referred to as a lowering operation. The first distance is a distance that allows the recording medium 5 and the detection light DL to be released from contact with each other.

[0039] The lift control unit 105 is configured to control the first motor 39A of the first table moving mechanism 37 to move the table 35 upward. When detecting the height of the recording medium 5, if the detection light DL is not partially or entirely blocked by the recording medium 5, the lift control unit 105 lifts the table 35 by a predetermined distance (hereinafter referred to as the "second distance").

[0040] The storage unit 106 stores the height of the table 35 when ink is ejected from the ink head 60 onto the recording medium 5 to form an image (i.e., when printing). The storage unit 106 stores the height of the table 35 moved by the lowering control unit 104 and / or the rising control unit 105 so that the distance in the vertical direction Z between the upper end of the recording medium 5 placed on the table 35 and the detection light DL is the minimum distance. Although details will be described later, in this embodiment, the lowering control unit 104 repeatedly lowers the table 35 by a first distance when the table 35 comes into contact with the detection light DL, thereby determining the distance in the vertical direction Z between the upper end of the recording medium 5 and the detection light DL. The above-mentioned "minimum distance" is the distance at which the upper end of the recording medium 5 does not come into contact with the detection light DL, and the "minimum distance" is the same as the first distance or a distance shorter than the first distance.

[0041] The print instruction unit 107 controls the second table moving mechanism 38 and the ink head 60 to execute printing on the recording medium 5. The second table moving mechanism 38 moves the table 35 forward by a predetermined distance, and ink is ejected from the ink head 60 onto the recording medium 5. By repeating these steps, printing is performed on the recording medium 5.

[0042] The above describes the configuration of the printer 10. Next, a procedure will be described in which the printer 10 detects the height of the recording medium 5 and determines the height of the table 35 during printing. Figure 8 is a flowchart showing the procedure for determining the height of the table 35 and printing.

[0043] In step S101, the movement control unit 101 controls the second motor 39B of the second table moving mechanism 38 to move the table 35 to the frontmost position. In step S102, the lowering control unit 104 and the raising control unit 105 control the first table moving mechanism 37 to move the table 35 to a predetermined height. In this embodiment, the user moves the height of the table 35 so that the detection light DL and the recording medium 5 at least partially overlap in the vertical direction. However, the determination of whether the detection light DL and the recording medium 5 at least partially overlap in the vertical direction is, for example, a determination by the user's naked eye, and it is unclear at the time of step S102 whether the detection light DL and the recording medium 5 actually at least partially overlap in the vertical direction. In addition, the user places the recording medium 5 on the table 35 at any timing until the completion of step S102. The order of steps S101 and S102 may be reversed.

[0044] In step S103, the movement control unit 101 controls the second motor 39B of the second table moving mechanism 38 to perform a table moving operation to move the table 35 backward. Fig. 8A is a diagram showing a cross section AA in Fig. 4 at step S103. Since the recording medium 5 is disposed in front of the detection light DL, the recording medium 5 does not block the detection light DL. Therefore, at this time, the signal output by the light receiving element 41a is ON, and the signal received by the signal receiving unit 102 is also ON.

[0045] In step S104, the determination unit 103 performs a determination operation to determine whether or not the detection light DL is partially or entirely blocked by the recording medium 5. FIG. 8B is a cross-sectional view of the AA section in FIG. 4 when the recording medium 5 blocks the detection light DL. FIG. 8C is a view of the printer 10 as viewed from the front in FIG. 8B. In FIG. 8B and FIG. 8C, the detection light DL is partially or entirely blocked by the recording medium 5, so the amount of light received by the light receiving element 41a (see FIG. 6) is less than that in FIG. 8A. Therefore, the signal output by the light receiving element 41a is OFF, and the signal received by the signal receiving unit 102 is also OFF. When the determination unit 103 detects that the signal received by the signal receiving unit 102 has turned OFF, the determination unit 103 determines that the detection light DL is partially or entirely blocked by the recording medium 5, that is, the upper end of the recording medium 5 is located above the detection light DL. If the determination unit 103 determines that the detection light DL is partially or entirely blocked by the recording medium 5, the process proceeds to step S105. If the determination unit 103 determines that the detection light DL is not partially or entirely blocked by the recording medium 5, the process proceeds to step S107.

[0046] In step S105 shown in Fig. 7, the movement control unit 101 stops the movement of the table 35. After the movement of the table 35 has stopped, the lowering control unit 104 performs a lowering operation to lower the table 35 by the first distance. By performing the lowering operation, the detection light DL is not blocked by the recording medium 5. In step S106, the movement control unit 101 performs the table moving operation again. The movement direction of the table 35 by the table moving operation is the same as the movement direction of the table 35 before the table 35 stopped in step S105.

[0047] In step S107 shown in FIG. 7, the table 35 is moved backward. Since it is determined that the detection light DL is not partially or entirely blocked by the recording medium 5, unlike step S105, the table 35 is not stopped and is moved to the rearmost position. Therefore, the height of the recording medium 5 cannot be detected by the detection light DL. At this time, it is necessary to detect the height of the recording medium 5 again. In step S108, the lift control unit 105 lifts the table 35 by the second distance. In step S109, the movement control unit 101 moves the table 35 from the rear to the front. Then, the process returns to step S104.

[0048] In step S110, the determination unit 103 performs a determination operation to determine whether or not the detection light DL is partially or entirely blocked by the recording medium 5. If it is determined that the detection light DL is partially or entirely blocked by the recording medium 5, the process returns to step S105. If it is determined that the detection light DL is not partially or entirely blocked by the recording medium 5, the process proceeds to step S111. As described above, the lowering operation of step S105, the table moving operation of step S106, and the determination operation of step S110 are repeated until the determination unit 103 determines that the detection light DL is not partially or entirely blocked by the recording medium 5 in step S110. When it is determined in step S110 that the detection light DL is not partially or entirely blocked by the recording medium 5, the detection of the height of the recording medium 5 is completed, and the interval between the ink head 60 and the recording medium 5 can be set to a predetermined interval. In step S105, the descent control unit 104 lowers the table 35 by a first distance, so that when the contact between the recording medium 5 and the detection light DL is lost in step S110, the distance between the recording medium 5 and the detection light DL in the vertical direction Z is the same as or less than the first distance.

[0049] In step S111, the movement control unit 101 moves the table 35 backward. Since it is determined in step S110 that the detection light DL is not partially or entirely blocked by the recording medium 5, in step S111, the table 35 is moved to the rearmost position.

[0050] In step S112, memory unit 106 stores the height of table 35 at this time as the height of table 35 during printing. Thus, the height of table 35 during printing is determined. In step S113, print instruction unit 107 issues an instruction to print on recording medium 5, and printer 10 prints on recording medium 5. At this time, table 35 is moved from the rearmost position to the front.

[0051] As described above, according to the printer 10 of this embodiment, the first slit 32a is formed in the first optical axis tube 32 of the light-emitting unit 30. The first slit depth L1 is longer than the first slit height t1. When the detection light DL emitted from the light-emitting element 31a of the light-emitting unit 30 passes through the first slit 32a, the detection light DL diffused in the vertical direction Z is blocked by the side of the first slit 32a penetrating in the main scanning direction Y. This allows the detection light DL, which is suppressed from being diffused in the vertical direction Z, to proceed from the first slit opening 32aa. When the detection light DL diffuses in the vertical direction Z, the amount of the detection light DL in the space between the light-emitting unit 30 and the light-receiving unit 40 varies depending on the position in the vertical direction Z. Therefore, there is a risk that a part or all of the detection light DL is blocked by the recording medium 5, and the height of the recording medium 5 when the signal output by the light-receiving element 41a is turned OFF varies. However, in the case of this embodiment, as described above, the detection light DL is suppressed from being diffused in the vertical direction Z. Therefore, the height of the recording medium 5, which is detected when the detection light DL is partially or entirely blocked by the recording medium 5, can be detected more accurately.

[0052] According to the printer 10 of this embodiment, the first slit depth L1 is longer than the first slit width w1. When the first slit width w1 is longer, the area obtained by multiplying the first slit width w1 and the first slit height t1 is larger. The larger the area, the greater the amount of light of the detection light DL. When the amount of light of the detection light DL increases, the detection light DL reaches a greater distance, so that the light receiving unit 40 can receive the detection light DL even if the interval between the light emitting unit 30 and the light receiving unit 40 is increased. On the other hand, the increase in the amount of light of the detection light DL makes it easier for the detection light DL to diffuse in the vertical direction Z. Therefore, by making the first slit depth L1 longer than the first slit width w1, the amount of light of the detection light DL can be increased while suppressing the diffusion of the detection light DL. Therefore, the interval between the light emitting unit 30 and the light receiving unit 40 can be relatively long while maintaining the accuracy of the detection of the height of the recording medium 5.

[0053] According to the printer 10 of this embodiment, the second slit 42a is formed in the second optical axis tube 42 of the light receiving unit 40. The second slit depth L2 is longer than the second slit height t2. The detection light DL emitted from the light emitting unit 30 and entering the second slit 42a from the second slit opening 42aa is prevented from diffusing in the vertical direction Z by the side of the second slit 42a penetrating in the main scanning direction Y. This makes it easier for the detection light DL entering the second slit 42a to proceed toward the light receiving element 41a. Therefore, the detection light DL received by the light receiving unit 40 is suppressed from varying. This allows the height of the recording medium 5 to be detected more accurately.

[0054] According to the printer 10 of this embodiment, the first optical axis tube 32 of the light emitting unit 30 is provided with the first fixing portion 32b, so that the light emitting device 31 and the first optical axis tube 32 are both fixed to the first mounting member 33 by the bolt 32c. This reduces the number of parts required compared to, for example, fixing the light emitting device 31 and the first optical axis tube 32 by a bolt and fixing the first optical axis tube 32 and the first mounting member 33 by a bolt. The same is true for the light receiver 41, the second optical axis tube 42, and the second mounting member 43 of the light receiving unit 40. Here, when the orientation of the light emitting unit 30 in the main scanning direction Y, the sub-scanning direction X, and the vertical direction Z is shifted, the direction in which the detection light DL is irradiated changes. When the orientation of the light receiving unit 40 in the main scanning direction Y, the sub-scanning direction X, and the vertical direction Z is shifted, the orientation in which the detection light DL is received changes, and the amount of light received changes. That is, misalignment of the light-emitting unit 30 and the light-receiving unit 40 in the main scanning direction Y, the sub-scanning direction X, and the vertical direction Z prevents accurate detection of the height of the recording medium 5. Therefore, it is desirable that the light-emitting unit 30 and the light-receiving unit 40 are provided so that there is no misalignment of the light-emitting unit 30 and the light-receiving unit 40 in the main scanning direction Y, the sub-scanning direction X, and the vertical direction Z. However, when the number of parts constituting the light-emitting unit 30 and the light-receiving unit 40 increases, the possibility that the light-emitting unit 30 and the light-receiving unit 40 will be misaligned in the main scanning direction Y, the sub-scanning direction X, and the vertical direction Z increases due to the accumulation of the dimensional tolerances of each part. Therefore, it is preferable that the number of parts constituting the light-emitting unit 30 and the light-receiving unit 40 is as small as possible. In this embodiment, as described above, the number of parts constituting the light-emitting unit 30 and the light-receiving unit 40 can be reduced, so that the misalignment of the light-emitting unit 30 and the light-receiving unit 40 is less likely to occur. Therefore, the light-receiving unit 40 can receive the detection light DL well, and the height of the recording medium 5 is detected more accurately.

[0055] 6, in the printer 10 of this embodiment, the lowering operation of step S105, the table movement operation of step S106, and the judgment operation of step S110 are repeated until the judgment unit 103 judges in step S110 that the detection light DL is not partially or entirely blocked by the recording medium 5. In this way, even if the upper surface of the recording medium 5 has an uneven shape, the highest position of the recording medium 5 can be detected.

[0056] In the printer 10 of this embodiment, the height of the recording medium 5 is detected while the table 35 is moved backward. When the detection of the height of the recording medium 5 is completed, the print instruction unit 107 conveys the recording medium 5 forward and performs printing. Here, the user opens the front cover 23 and places the recording medium 5 on the table 35, so when placing the recording medium 5 on the table 35, it is necessary to move the table 35 forward of the detection light DL. Therefore, for example, when detecting the height of the recording medium 5 from the rear to the front, it is necessary to move the table 35 to the rearmost position after placing the recording medium 5 on the table 35. However, in the printer 10 of this embodiment, it is possible to detect the height of the recording medium 5 while moving the table 35 backward. Furthermore, after detecting the height of the recording medium 5, the table 35 can be moved forward by the print instruction unit 107 to perform printing. As a result, it is not necessary to move the table 35 before detecting the height of the recording medium 5 or starting printing. Therefore, it is possible to efficiently improve the time from placing the recording medium 5 on the table 35 to completing printing.

[0057] According to the printer 10 of this embodiment, the light emitting element 31a of the light emitter 31 is a light emitting diode. In order to prevent the detection light DL from diffusing in the vertical direction Z, for example, a light emitting element that irradiates laser light can be used. However, the light emitting element that irradiates laser light is relatively expensive. Therefore, if the light emitting unit 30 is configured using a light emitting element that irradiates laser light, the cost of the light emitting unit 30 becomes relatively expensive. On the other hand, the light emitting diode is inexpensive compared to the light emitting element that irradiates laser light. The light irradiated from the light emitting diode is more likely to diffuse in the vertical direction Z than the laser light, but as in this embodiment, the light emitting unit 30 has the first optical axis tube 32, so that the diffusion of the detection light DL in the vertical direction Z is suppressed. Therefore, it is possible to use a light emitting diode for the light emitting element 31a, and the light emitting unit 30 can be configured relatively inexpensively.

[0058] According to the printer 10 of this embodiment, the light receiving element of the light receiver 41 is a photosensor. For example, even if the detection light DL is diffused in the vertical direction Z, by using a photomultiplier tube, the variation in the height of the recording medium 5 when the determination unit 103 determines that a part or all of the detection light DL is blocked by the recording medium 5 can be suppressed. Since the photomultiplier tube is a light receiving element having a relatively high sensitivity, when a part or all of the detection light DL is blocked by the recording medium 5, the change in the amount of light received by the light receiving element can be detected with a relatively high sensitivity. Therefore, when an area of ​​the detection light DL with a relatively large amount of light is blocked by the recording medium 5, the determination by the determination unit 103 is configured to be switched, thereby suppressing the variation in the height of the recording medium 5 detected. However, the photomultiplier tube is relatively expensive. Therefore, if the light receiving unit 40 is configured using a photomultiplier tube, the cost of the light receiving unit 40 becomes relatively expensive. On the other hand, the photosensor is cheaper than the photomultiplier tube. Therefore, by using a photosensor as the light receiving element 41a, the light receiving section 40 can be constructed at a relatively low cost.

[0059] Although a preferred embodiment of the present invention has been described above, the above-described embodiment is merely an example, and the present invention can be embodied in various other forms.

[0060] The technology disclosed herein can be applied to various types of printers. In addition to the flatbed type printer 10 shown in the embodiment described above, the technology can also be applied to a so-called roll-to-roll type printer 10 that conveys a roll-shaped recording medium 5 in the sub-scanning direction X. The technology can also be applied to a so-called gantry type printer 10 that prints by placing the medium on a table and moving the ink head in the main scanning direction Y and the sub-scanning direction X relative to the table. [Explanation of symbols]

[0061] 5 Recording media 10 Printers 30 Light emitting part 32 1st optical axis tube (optical axis tube) 32a Slit 35 Table (Placement stand) 36 Table movement mechanism (mounting table movement mechanism) 40 Light receiving part 60 Ink Head DL Detection light L1 First slit depth t1 First slit height

Claims

1. a mounting table on which a recording medium is mounted; a mounting table moving mechanism for moving the mounting table; a light emitting unit that is disposed above the mounting table and on one side of the mounting table in a main scanning direction and that irradiates detection light toward the other side of the main scanning direction; a light receiving unit that is disposed on the other side of the mounting table in the main scanning direction, receives the detection light from the light emitting unit, and outputs a signal corresponding to an amount of received light, The light emitting unit includes: a light emitter having a light emitting element that emits the detection light; a detection light limiting section adjacent to the light emitter on the other side of the main scanning direction and having a first slit penetrating in the main scanning direction, An inkjet printer, wherein a first slit depth, which is the length of the first slit in the main scanning direction, is longer than a vertical length of a first slit opening provided at the other end of the first slit in the main scanning direction.

2. 2. The inkjet printer according to claim 1, wherein the length of the first slit depth is longer than the first slit width, which is the length of the first slit in a sub-scanning direction perpendicular to the main scanning direction.

3. The light receiving unit is a light receiver having a light receiving element that receives the detection light; a light-receiving-side detection light limiting section that is adjacent to the light receiver on one side of the main scanning direction and has a second slit that penetrates in the main scanning direction, 2. The inkjet printer according to claim 1, wherein a second slit depth, which is the length of the second slit in the main scanning direction, is longer than a vertical length of a second slit opening provided at one end of the second slit in the main scanning direction.

4. a first attachment member to which the light emitting unit is fixed; the detection light limiting unit includes a first fixing portion that fixes the first attachment member together with the light emitting unit, a second mounting member to which the light receiving unit is fixed, The inkjet printer according to claim 3 , wherein the light-receiving side detection light limiting section includes a second fixing section that is fixed to the first mounting member together with the light-receiving section.

5. the mounting table moving mechanism moves the mounting table in a vertical direction and a sub-scanning direction; A control device for controlling the mounting table moving mechanism, The control device includes: a movement control unit that performs a mounting table moving operation to move the mounting table either forward or backward; a signal receiving unit that receives the signal output from the light receiving unit; a determination unit that performs a determination operation of determining whether or not the detection light is partially or entirely blocked by the recording medium based on the signal received by the signal receiving unit; a lowering control unit that performs a lowering operation to lower the placement table when the determination unit determines that the detection light is partially or entirely blocked by the recording medium, until the determination unit determines that the detection light is not partially or entirely blocked by the recording medium, 2. The inkjet printer according to claim 1, wherein when the result of the determination operation indicates that the detection light is not partially or completely blocked by the recording medium, the stage moving operation, the determination operation and the lowering operation are repeated until the stage moves either forward or backward of the detection light by the stage moving operation.

6. the movement control unit moves the mounting table from in front of the detection light to behind the detection light, 6. The inkjet printer according to claim 5, further comprising a print instruction unit configured to, when the result of the determination operation indicates that the detection light is not partially or entirely blocked by the recording medium, move the stage behind the detection light by a stage moving operation, and then move the stage forward to perform printing.

7. 2. The inkjet printer according to claim 1, wherein the light emitting portion is formed of a light emitting diode.

8. 2. The inkjet printer according to claim 1, wherein the light receiving portion is formed of a photodiode.

Images