Ink jet printer

Abstract

To detect an end of a recording medium while suppressing drying of a nozzle of an ink head.SOLUTION: A printer 10 includes: an ink head 24 which has a nozzle surface 25 provided with a nozzle for discharging ink to a recording medium 5 mounted in a platen 16; a first carriage 28 which is mounted with the ink head 24 thereon and is movable in a main scanning direction Y; a first sensor 31 which detects an end in a main scanning direction Y of the recording medium 5; a second carriage 38 which is detachably provided in the first carriage 28, is mounted with the first sensor 31 thereon, and is movable in the main scanning direction Y; a carriage moving mechanism 40 which moves the second carriage 38; and a cap 71 which forms a sealed space 26 between the cap and the nozzle surface 25 when mounted in the ink head 24. The cap 71 is mounted in the ink head 24 and forms the sealed space 26 between the cap and the nozzle surface 25 when the second carriage 38 independently moves.SELECTED DRAWING: Figure 3B

Description

[Technical Field]

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

[0002] Inkjet printers that print on a recording medium using an inkjet method have been known for some time. This type of inkjet printer includes, for example, a platen on which the recording medium is placed, an ink head having nozzles that eject ink onto the recording medium placed on the platen and a nozzle surface on which the nozzles are formed, and a carriage on which the ink head is mounted. Inkjet printers typically need to detect the position of the recording medium before starting printing. For example, Patent Document 1 discloses an inkjet printer in which an optical sensor that detects the edge of the recording medium is mounted on the carriage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-101981 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 requires that a carriage equipped with an optical sensor be moved in the main scanning direction when detecting the edge of a recording medium. Because the carriage is equipped with an ink head in addition to the optical sensor, the ink head also moves in the main scanning direction when detecting the edge of a recording medium. When the carriage moves through the printing area in the main scanning direction, the nozzle surface of the ink head is exposed to the outside. Therefore, if ink is not ejected from the nozzles, the nozzles and nozzle surface may dry out. If the nozzles dry out, the nozzles may become clogged or ink may adhere to the nozzle surface. Therefore, after detecting the edge of a recording medium using an optical sensor, a cleaning operation is required to eject ink from the nozzles. Because the cleaning operation takes a relatively long time and uses a relatively large amount of ink, it is desirable to reduce the number of cleaning operations required when detecting the edge of a recording medium.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to provide an inkjet printer that can detect the edge of a recording medium while preventing the nozzles of the ink head from drying out. [Means for solving the problem]

[0006] The inkjet printer according to the present invention includes a mounting table on which a recording medium is placed, an ink head having nozzles for ejecting ink onto the recording medium placed on the mounting table and a nozzle surface on which the nozzles are formed, a first carriage on which the ink head is mounted and movable in a main scanning direction, a first sensor for detecting an edge in the main scanning direction of the recording medium placed on the mounting table, a second carriage detachably attached to the first carriage and movable in the main scanning direction on which the first sensor is mounted, a carriage movement mechanism for moving the second carriage in the main scanning direction, a cap detachably formed on the ink head and covering the nozzle surface when attached to the ink head to form an airtight space between the cap and the nozzle surface, and a control device connected to the first sensor. The cap is configured to be attached to the ink head and to form the airtight space between the cap and the nozzle surface when the second carriage moves independently.

[0007] According to the inkjet printer of the present invention, a second carriage equipped with a first sensor that detects the edge of the recording medium in the main scanning direction is detachably mounted on a first carriage equipped with an ink head. Therefore, when the first sensor detects the edge of the recording medium in the main scanning direction, the second carriage can move in the main scanning direction independently of the first carriage. Here, when the second carriage moves independently, a cap is attached to the ink head, forming an enclosed space between the cap and the nozzle face. This prevents the nozzles and nozzle face from being exposed to the outside, preventing the nozzles and nozzle face from drying out. Because a cap is attached to the ink head when detecting the edge of the recording medium in the main scanning direction, a cleaning operation that ejects ink from the nozzles is not required. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an inkjet printer that can detect the edge of a recording medium while preventing the nozzles of the ink head from drying out. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of a printer according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view of a printer according to an embodiment. [Figure 3A] FIG. 2 is a front view of the ink head unit and the sensor unit. [Figure 3B] FIG. 2 is a front view of the ink head unit and the sensor unit. [Figure 4] FIG. 2 is an enlarged plan view of a portion of the structure around the platen according to the embodiment. [Figure 5] FIG. 2 is a diagram showing the configuration of the vicinity of a capping device according to an embodiment, and is a front view showing a state in which a cap is attached to an ink head. [Figure 6] FIG. 2 is a block diagram of a control system of a printer according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An inkjet printer (hereinafter simply referred to as "printer") according to an embodiment of the present invention will be described below with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention in any way. Furthermore, members and parts that perform the same function are given the same reference numerals, and duplicate descriptions will be omitted or simplified as appropriate.

[0011] FIG. 1 is a front view of a printer 10 according to this embodiment. The printer 10 prints on a recording medium 5. The recording medium 5 is, for example, formed into a long sheet and wound into a roll. The recording medium 5 may also be a sheet-like sheet that is cut into a predetermined length from a roll. The recording medium 5 is, for example, recording paper. However, the recording medium 5 is not limited to recording paper. The recording medium 5 includes paper such as plain paper and inkjet printing paper, as well as those made from resin materials such as polyvinyl chloride (PVC) and polyester, metal plates made from aluminum, iron, etc., glass plates, wood plates, cardboard, etc. When the recording medium 5 is made of paper or a resin material, the color of the recording medium 5 is typically white.

[0012] In the following description, left, right, top, and bottom refer to the left, right, top, and bottom directions, respectively, as seen from the perspective of an operator standing in front of the printer 10. Furthermore, when the operator is facing the printer 10, the direction from the rear of the printer 10 toward the operator is referred to as the front, and the direction from the operator toward the rear of the printer 10 is referred to as the rear. The symbols F, Rr, L, R, U, and D in the drawings represent the front, rear, left, right, top, and bottom, respectively. The first carriage 28 and the second carriage 38, which will be described later, are movably mounted to the left and right. The rear side of the printer 10 is referred to as the upstream side, and the front side of the printer 10 is referred to as the downstream side. The recording medium 5 is transported from the upstream side to the downstream side. In this embodiment, the movement direction of the first carriage 28 and the second carriage 38 is referred to as the main scanning direction Y, and the transport direction of the recording medium 5 is referred to as the sub-scanning direction X. Here, the main scanning direction Y corresponds to the left-right direction, and the sub-scanning direction X corresponds to the front-to-back direction. The main scanning direction Y and the sub-scanning direction X are perpendicular to each other. However, the main scanning direction Y and the sub-scanning direction X are not particularly limited, and can be set appropriately depending on the configuration of the printer 10, etc.

[0013] As shown in FIG. 1, the printer 10 includes a printer body 10a, legs 11, an operation panel 12, a platen 16 on which a recording medium 5 is placed, an ink head unit 20, a sensor unit 30, a carriage movement mechanism 40, a medium movement mechanism 55, a first control device 80, and a second control device 90 (see FIG. 3A). The printer body 10a has a casing extending in the main scanning direction Y. The legs 11 support the printer body 10a and are provided on the underside of the printer body 10a. The operation panel 12 is provided, for example, on the front right side of the printer body 10a. However, the location of the operation panel 12 is not particularly limited. The operation panel 12 is used, for example, by an operator to perform printing-related operations. Although not shown, the operation panel 12 is equipped with a display unit that displays printing-related information such as resolution and ink density, as well as the status of the printer 10 during printing, and an input unit for inputting printing-related information.

[0014] The platen 16 supports the recording medium 5 when printing on the recording medium 5. The recording medium 5 is placed on the platen 16. The platen 16 has a placement surface 16A (see FIG. 2) on which the recording medium 5 is placed. In this embodiment, the placement surface 16A is black, but the color of the placement surface 16A is not limited to black. The recording medium 5 is placed on the placement surface 16A of the platen 16 before printing on the recording medium 5. The platen 16 is an example of a placement table. Printing on the recording medium 5 is performed on the platen 16. As shown in FIG. 1, the platen 16 extends in the main scanning direction Y. The platen 16 is supported by the printer main body 10a.

[0015] As shown in FIG. 2, the platen 16 is formed with a plurality of suction holes 16H that penetrate vertically. The suction holes 16H include downstream suction holes 16HF located in front of the ink head 24 (described later) (i.e., downstream in the sub-scanning direction X) and upstream suction holes 16HR located behind the ink head 24 (i.e., upstream in the sub-scanning direction X). As shown in FIG. 4, the downstream suction holes 16HF and the upstream suction holes 16HR are aligned in the main scanning direction Y and arranged in two rows in the sub-scanning direction X. As indicated by arrow FL in FIG. 2, air is sucked into the platen 16 through the suction holes 16H by a fan (not shown). This attracts the recording medium 5 placed on the platen 16 to the platen 16, preventing the recording medium 5 from floating up. Also, as shown in FIG. 4, the platen 16 is formed with a groove 16D that extends in the main scanning direction Y. The groove 16D is formed across the entire platen 16 in the main scanning direction Y. The grooves 16D are formed between the upstream suction holes 16HR arranged in two rows in the sub-scanning direction X.

[0016] As shown in FIG. 1, the printer 10 has a central wall 14 that extends in the main scanning direction Y and the up-down direction. The central wall 14 is supported by the printer body 10a. The central wall 14 is disposed above a platen 16. A gap is formed between the central wall 14 and the platen 16, allowing the recording medium 5 to pass through. As shown in FIG. 2, the printer 10 has a guide rail 15. The guide rail 15 extends in the main scanning direction Y. The guide rail 15 is provided on the central wall 14. The guide rail 15 is disposed above the platen 16.

[0017] As shown in FIG. 3A, the ink head unit 20 includes a first carriage 28 and a plurality of ink heads 24. The first carriage 28 is engaged with the guide rail 15. The first carriage 28 is configured to be movable in the main scanning direction Y along the guide rail 15. As described below, the first carriage 28 moves in the main scanning direction Y together with a second carriage 38 of the sensor unit 30 (described below). The first carriage 28 carries an ink head 24. The ink head 24 is configured to be movable in the main scanning direction Y in conjunction with the movement of the first carriage 28. The ink head 24 ejects ink onto the recording medium 5 placed on the platen 16 and has a plurality of nozzles (not shown) aligned in the sub-scanning direction X, and a nozzle surface 25 on which the plurality of nozzles are formed. The ink head 24 prints a predetermined image on the recording medium 5. As shown in FIG. 3A, five ink heads 24 are mounted on the first carriage 28. However, the number of ink heads 24 is not limited to five.

[0018] As shown in FIG. 3A, the sensor unit 30 includes a second carriage 38, a first sensor 31, a sheet cutter 33, and a second control device 90. The second carriage 38 is engaged with the guide rail 15. The second carriage 38 is configured to be movable in the main scanning direction Y along the guide rail 15. The second carriage 38 is detachably attached to the first carriage 28. As will be described later, the second carriage 38 moves in the main scanning direction Y together with the first carriage 28 of the ink head unit 20 or independently (i.e., independently from the first carriage 28). The second carriage 38 is equipped with the first sensor 31, the sheet cutter 33, and the second control device 90. The first sensor 31 and the sheet cutter 33 are configured to be movable in the main scanning direction Y in conjunction with the movement of the second carriage 38.

[0019] The first sensor 31 detects the edge of the recording medium 5 placed on the platen 16 in the main scanning direction Y (i.e., the boundary between the recording medium 5 and the platen 16). More specifically, the first sensor 31 detects the right edge 5R (see FIG. 1) and the left edge 5L (see FIG. 1) of the recording medium 5. The type of the first sensor 31 is not particularly limited, but examples include a reflective photosensor. In this embodiment, the first sensor 31 is a color sensor (typically a color sensor that detects RGB values). The first sensor 31 is connected to the second control device 90. As shown in FIG. 4, the movement trajectory ML of the first sensor 31 mounted on the second carriage 38 overlaps with the upstream suction hole 16HR (in this embodiment, the upstream suction hole 16HR is located forward of the groove 16D) in a plan view. The attachment position of the first sensor 31 is aligned with the upstream suction hole 16HR in the sub-scanning direction X. That is, when the first sensor 31 moves in the main scanning direction Y, the first sensor 31 passes directly above the upstream suction hole 16HR.

[0020] 3A, the sheet cutter 33 is configured to be able to cut the recording medium 5 placed on the platen 16 only in the main scanning direction Y. The sheet cutter 33 is mounted on a second carriage 38. The sheet cutter 33 is configured to be able to move in the vertical direction. The sheet cutter 33 is controlled by the second control device 90. When cutting the recording medium 5, the sheet cutter 33 moves along a groove 16D formed in the platen 16 (see FIG. 4).

[0021] The carriage movement mechanism 40 moves the first carriage 28 of the ink head unit 20 and the second carriage 38 of the sensor unit 30 in the main scanning direction Y relative to the recording medium 5 placed on the platen 16. The carriage movement mechanism 40 moves the first carriage 28 and the second carriage 38 in the main scanning direction Y. The configuration of the carriage movement mechanism 40 is not particularly limited. As shown in FIG. 1, the carriage movement mechanism 40 includes a first pulley 41, a second pulley 42, an endless belt 43, and a carriage motor 44. The first pulley 41 is provided on the left end of the guide rail 15. The second pulley 42 is provided on the right end of the guide rail 15. The belt 43 is wound around the first pulley 41 and the second pulley 41. The belt 43 is fixed to the upper rear surface of the second carriage 38 (see also FIG. 3A). The second pulley 42 is connected to the carriage motor 44. However, the carriage motor 44 may be connected to the first pulley 41. In this case, the carriage motor 44 is driven to rotate the second pulley 42, causing the belt 43 to run between the first pulley 41 and the second pulley 42. This causes the second carriage 38 to move in the main scanning direction Y. That is, the carriage motor 44 moves the second carriage 38 in the main scanning direction Y. As will be described later, the first carriage 28 moves in the main scanning direction Y in conjunction with the movement of the second carriage 38. The carriage motor 44 indirectly moves the first carriage 28 in the main scanning direction Y via the second carriage 38. The carriage motor 44 is controlled by the first control device 80.

[0022] As shown in FIG. 3A, a first connecting member 29 formed by a magnet is provided on the left side of the first carriage 28. A second connecting member 39 formed by a magnet is fixed to the right side of the second carriage 38. The first connecting member 29 is detachably connected to the second connecting member 39. In this embodiment, the first connecting member 29 and the second connecting member 39 utilize magnetic force. However, the first connecting member 29 and the second connecting member 39 are not limited to those utilizing magnetic force, and may have other configurations such as an engaging member. An L-shaped first receiving bracket 27 is provided on the right side of the first carriage 28.

[0023] As shown in FIG. 3A, a left side frame 7L and a right side frame 7R are disposed on the left and right sides of the platen 16, respectively. The right side frame 7R is provided with a locking device 45 for locking the ink head unit 20 in a standby position. The locking device 45 includes a second receiving bracket 46 that is hooked onto the first receiving bracket 27, and a locking solenoid 47 (see FIG. 6) that moves the second receiving bracket 46 between a locked position (see FIG. 3B) and an unlocked position (see FIG. 3A). The locking solenoid 47 is controlled by a first control device 80.

[0024] As shown in FIG. 3A, when a predetermined image is printed on the recording medium 5 by the ink head 24, the second receiving metal fitting 46 is set to the unlocked position. When the second carriage 38 of the sensor unit 30 moves to the right and the second connecting member 39 comes into contact with the first connecting member 29, the second carriage 38 and the first carriage 28 are connected. As a result, the ink head unit 20 becomes movable in the main scanning direction Y together with the sensor unit 30. That is, when the carriage motor 44 (see FIG. 4) is driven, the first carriage 28 and the second carriage 38 move in the main scanning direction Y. On the other hand, when the first sensor 31 detects the edge of the recording medium 5 or the sheet cutter 33 cuts the recording medium 5, the ink head unit 20 is positioned in the standby position and the second receiving metal fitting 46 of the locking device 45 is set to the locked position, as shown in FIG. 3B. This prevents the ink head unit 20 from moving in the main scanning direction Y. When the second carriage 38 moves to the left, the second connecting member 39 and the first connecting member 29 move away from each other, and the connection between the second carriage 38 and the first carriage 28 is released. As a result, with the ink head unit 20 waiting in the standby position, only the sensor unit 30 can move in the main scanning direction Y. In other words, when the carriage motor 44 is driven, only the second carriage 38 moves in the main scanning direction Y.

[0025] As shown in FIG. 2, the printer 10 includes a linear encoder 65. The linear encoder 65 detects the positions of the first carriage 28 and the second carriage 38. The configuration of the linear encoder 65 is not particularly limited, but may be, for example, a photoelectric (transmission) linear encoder. The linear encoder 65 includes a linear scale 66 extending in the main scanning direction Y, a second sensor 67 (see FIG. 4), and a third sensor 68 (see FIG. 4). The scale 66 is provided on the central wall 14. The scale 66 is disposed above the guide rail 15. The scale 66 has a plurality of graduations or slits arranged at predetermined intervals in the main scanning direction Y. The second sensor 67 measures the graduations formed on the scale 66. The second sensor 67 is provided on the second carriage 38. The second sensor 67 is connected to a second control device 90 (see FIG. 3A). The second sensor 67 is disposed so as to sandwich the scale 66. The position of the second carriage 38 can be detected based on the graduations of the scale 66 detected by the second sensor 67. The third sensor 68 measures the graduations formed on the scale 66. The third sensor 68 is provided on the first carriage 28. The third sensor 68 is connected to the first control device 80 (see FIG. 1). The third sensor 68 is arranged so as to sandwich the scale 66. The position of the first carriage 28 can be detected based on the graduations of the scale 66 detected by the third sensor 68.

[0026] The medium moving mechanism 55 moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X relative to the first carriage 28 and the second carriage 38. The medium moving mechanism 55 moves the recording medium 5 placed on the platen 16 in the sub-scanning direction X. As shown in FIG. 1, the medium moving mechanism 55 includes a grit roller 57, a feed motor 58 (see FIG. 6), a pinch roller 60, and a holding shaft 64.

[0027] As shown in FIG. 1, the grit roller 57 is provided on the platen 16. The grit roller 57 is embedded in the platen 16 so that the top of the grit roller 57 is exposed to the outside. The grit rollers 57 are aligned in the main scanning direction Y. As shown in FIG. 4, the grit roller 57 is disposed rearward of the suction hole 16H (i.e., upstream in the sub-scanning direction X). The grit roller 57 is disposed below the pinch roller 60. The grit roller 57 sandwiches the recording medium 5 between itself and the pinch roller 60. A feed motor 58 (see FIG. 6) is connected to the grit roller 57. The feed motor 58 is controlled by the first control device 80. In other words, the grit roller 57 is controlled by the first control device 80. When the feed motor 58 is driven to rotate the grit roller 57 while the recording medium 5 is sandwiched between the grit roller 57 and the pinch roller 60, the recording medium 5 is transported in the sub-scanning direction X.

[0028] 1, the pinch roller 60 is disposed above the platen 16. The pinch roller 60 is disposed below the guide rail 15. The pinch roller 60 is disposed in a position opposite the grit roller 57. The pinch roller 60 presses down on the recording medium 5 placed on the platen 16 from above.

[0029] 1, the holding shaft 64 extends in the main scanning direction Y. The holding shaft 64 holds the pinch roller 60. By rotating the holding shaft 64 about its axis, the pinch roller 60 can be moved toward or away from the grit roller 57. The holding shaft 64 is rotatably supported by the printer main body 10a.

[0030] As shown in FIG. 1, the printer 10 includes a capping device 70. The capping device 70 is provided inside the printer main body 10a. The capping device 70 is located to the right of the platen 16. As shown in FIG. 5, the capping device 70 includes five caps 71, a cap moving mechanism 72, and a suction pump 74. The caps 71 and the cap moving mechanism 72 are located at a home position HP (see FIG. 4) located at the right end of the guide rail 15 (see FIG. 1). Here, the home position HP is a position where at least the ink head unit 20 waits while waiting to print, i.e., when no printing is being performed. However, the location of the home position HP is not particularly limited and may be the left end of the guide rail 15.

[0031] The caps 71 are members that prevent ink adhering to the nozzles (not shown) of the ink head 24 or the nozzle surface 25 from hardening and clogging the nozzles. The caps 71 are aligned in the main scanning direction Y. As shown in FIG. 5 , the caps 71 are attached to the ink head 24 and cover the nozzle surface 25 when the first carriage 28 of the ink head unit 20 is located at the home position HP (for example, during printing standby or when the second carriage 38 moves independently). When the caps 71 are attached to the ink head 24, a sealed space 26 is formed between the caps 71 and the nozzle surface 25. When the second carriage 38 of the sensor unit 30 moves independently, the caps 71 are attached to the ink head 24 and form a sealed space 26 between the caps 71 and the nozzle surface 25.

[0032] The cap moving mechanism 72 supports the cap 71. The cap moving mechanism 72 moves the cap 71 so that it can be attached to and detached from the ink head 24. In this embodiment, the cap moving mechanism 72 moves the cap 71 in the vertical direction. The configuration of the cap moving mechanism 72 is not particularly limited, but for example, it includes a drive motor 72A. By driving the drive motor 72A, the cap moving mechanism 72 moves the cap 71 in the vertical direction. When the first carriage 28 moves to the home position HP, the cap moving mechanism 72 moves the cap 71 upward to attach the cap 71 to the ink head 24. Furthermore, the cap moving mechanism 72 detaches the cap 71 from the ink head 24 by moving the cap 71 downward, for example, when starting printing.

[0033] As shown in FIG. 5, when the cap 71 is attached to the ink head 24, the suction pump 74 performs a cleaning operation by sucking in fluid (e.g., ink) from the sealed space 26 and causing the ink to be ejected from the nozzles (not shown). The suction port of the suction pump 74 is connected to the cap 71 via a flexible tube 75. The outlet of the suction pump 74 is connected to a waste liquid tank 79. The fluid from the sealed space 26 sucked by the suction pump 74 is stored in the waste liquid tank 79. The cleaning operation is an operation to eliminate nozzle ejection problems and prevent clogging of the nozzles of the ink head 24. The suction pump 74 is controlled by a first control device 80 (see FIG. 1).

[0034] As shown in FIG. 6, the overall operation of the printer 10 is controlled by a first control device 80 and a second control device 90. The first control device 80 is connected to the second control device 90. The configurations of the first control device 80 and the second control device 90 are not particularly limited. The first control device 80 and the second control device 90 are, for example, microcomputers. The hardware configuration of the microcomputer is not particularly limited, but may include, for example, an interface (I / F) that receives print data and other data from external devices such as a host computer, a central processing unit (CPU) that executes control program instructions, a read-only memory (ROM) that stores programs executed by the CPU, a random access memory (RAM) used as a working area for expanding the programs, and a storage device such as a memory that stores programs and various data. As shown in FIG. 1, the first control device 80 is provided inside the printer main body 10a. However, the first control device 80 does not have to be provided inside the printer main body 10a. For example, the first control device 80 may be a computer installed outside the printer main body 10a. In this case, the first control device 80 is connected to the printer 10 via a wired or wireless connection so as to be able to communicate with the printer 10. The second control device 90 is mounted on the second carriage 38, but may be provided inside the printer main body 10a or may be a computer installed outside the printer main body 10a. The first control device 80 is an example of another control device, and the second control device 90 is an example of a control device.

[0035] 6, the first control device 80 is communicatively connected to the ink head 24, locking solenoid 47, feed motor 58, carriage motor 44, suction pump 74, drive motor 72A, and third sensor 68. The first control device 80 controls the ink head 24, locking solenoid 47, feed motor 58, carriage motor 44, suction pump 74, and drive motor 72A. That is, the first control device 80 controls the carriage movement mechanism 40, medium movement mechanism 55, and cap movement mechanism 72. The first control device 80 identifies the position of the first carriage 28 based on the graduations of the scale 66 measured by the third sensor 68.

[0036] As shown in FIG. 6, the second control device 90 is communicatively connected to the first sensor 31, the second sensor 67, and the sheet cutter 33. The second control device 90 controls the sheet cutter 33. Based on information about the edge of the recording medium 5 detected by the first sensor 31 (i.e., the actual measurement value of the first sensor 31), the second control device 90 determines the position of the edge of the recording medium 5 (i.e., the positions of the right edge 5R and left edge 5L of the recording medium 5) and the length of the recording medium 5 in the main scanning direction Y (i.e., the width of the recording medium 5). The second control device 90 determines the position of the second carriage 38 based on the graduations of the scale 66 measured by the second sensor 67. Here, to more accurately measure the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y, it is necessary to know the measurement value of the first sensor 31 and the position of the second carriage 38 simultaneously. In the case where the second carriage 38 does not have a second sensor 67 mounted thereon to determine its position, the position of the second carriage 38 is determined from information from the motor encoder of the carriage motor 44, and the determined information is sent to the first control device 80. The measurement values ​​of the first sensor 31 are also processed by the first control device 80 and are therefore sent to the first control device 80. The first control device 80 calculates the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y from the measurement values ​​of the first sensor 31 and the information from the motor encoder sent to the first control device 80. In contrast, in this embodiment, the first sensor 31, which obtains the position of the edge of the recording medium 5, and the second sensor 67, which obtains the position of the second carriage 38, are communicatively connected to the second control device 90. Therefore, the second control device 90 can calculate the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y from the measurement values ​​of the first sensor 31 and the information from the second sensor 67 (the position of the second carriage 38). In this way, the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y are calculated by the second control device 90, so the amount of processing performed by the CPU of the first control device 80 can be reduced.

[0037] As described above, in the printer 10 of this embodiment, the second carriage 38, which is equipped with the first sensor 31 that detects the edge of the recording medium 5 in the main scanning direction Y, is detachably mounted on the first carriage 28 that is equipped with the ink head 24. Therefore, when the first sensor 31 detects the edge of the recording medium 5 in the main scanning direction Y, the second carriage 38 can move in the main scanning direction independently of the first carriage 28. When the second carriage 38 moves independently, a cap 71 is attached to the ink head 24, forming a sealed space 26 between the cap 71 and the nozzle surface 25. This prevents the nozzles and nozzle surface 25 from being exposed to the outside, thereby preventing the nozzles and nozzle surface 25 from drying out. Because the cap 71 is attached to the ink head 24 when detecting the edge of the recording medium 5 in the main scanning direction Y, a cleaning operation that ejects ink from the nozzles after detecting the edge is not required.

[0038] In the printer 10 of this embodiment, the second control device 90 determines the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y based on information about the edge of the recording medium 5 detected by the first sensor 31. In this way, by detecting the edge of the recording medium 5 in the main scanning direction Y with the first sensor 31, the position of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y can be determined.

[0039] In the printer 10 of this embodiment, the platen 16 is formed with a plurality of upstream suction holes 16HR that penetrate the platen 16 in the vertical direction and are aligned in the main scanning direction Y, and the movement trajectory ML of the first sensor 31 overlaps with the plurality of upstream suction holes 16HR in a plan view. The upstream suction holes 16HR bring the recording medium 5 into close contact with the platen 16, thereby suppressing lifting of the recording medium 5 from the platen 16. Here, because the first sensor 31 moves over the upstream suction holes 16HR, it can detect the edge of the recording medium 5 in the main scanning direction Y at a position where lifting of the recording medium 5 is minimized, thereby improving detection accuracy.

[0040] In the printer 10 of this embodiment, the first sensor 31 is a color sensor, and the mounting surface 16A of the platen 16 on which the recording medium 5 is placed is black, and the recording medium 5 is white. In this way, by increasing the brightness difference, the detection accuracy for the set threshold can be improved, and the right edge 5R and left edge 5L of the recording medium 5 can be detected more accurately.

[0041] The printer 10 of this embodiment is equipped with a sheet cutter 33 that is mounted on the second carriage 38 and can cut the recording medium 5 only in the main scanning direction Y. When the sheet cutter 33 cuts the recording medium 5 in the main scanning direction Y, a cap 71 is attached to the ink head 24, so that a cleaning operation of ejecting ink from the nozzles after cutting the recording medium 5 is not required.

[0042] The printer 10 of this embodiment is equipped with a linear encoder 65 having a linear scale 66 extending in the main scanning direction Y and a second sensor 67 that is provided on the second carriage 38 and measures the graduations of the scale 66. This allows the second control device 90 to calculate the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y based on the measurement value of the first sensor 31 and the value of the linear encoder 65 (here, the position of the second carriage 38), thereby reducing the amount of processing performed by the CPU of the first control device 80.

[0043] In the printer 10 of this embodiment, the linear encoder 65 further includes a third sensor 68 that is provided on the first carriage 28 and that measures the graduations of the scale 66. This allows the position of the ink head 24 to be measured more accurately. In other words, the landing position of the ink ejected onto the recording medium 5 becomes more accurate, resulting in improved image quality.

[0044] The printer 10 of this embodiment includes a first control device 80 that controls the ink head 24 and the carriage movement mechanism 40, and the second sensor 67 is connected to the second control device 90, which is provided on the second carriage 38. As a result, the second control device 90 calculates the position of the edge of the recording medium 5 and the length of the recording medium 5 in the main scanning direction Y, thereby reducing the amount of processing performed by the CPU of the first control device 80.

[0045] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0046] The sensor unit 30 may be provided with a cutter capable of cutting the recording medium 5 in the main scanning direction Y and the sub-scanning direction X, separate from the sheet cutter 33. In this case, the first sensor 31 may be configured to be able to detect crop marks printed on the recording medium. Here, crop marks are marks used for aligning the cutter when cutting the recording medium into a desired shape.

[0047] In the above-described embodiment, the printer 10 is provided with the first control device 80 and the second control device 90, but the first control device 80 and the second control device 90 may also be integrated. [Explanation of symbols]

[0048] 5. Recording media 5L left end 5R right end 10 Printer (inkjet printer) 16 Platen (mounting table) 24 ink head 25 Nozzle surface 26 Closed space 28 1st Carriage 31 First sensor 38 2nd Carriage 40 Carriage movement mechanism 71 Cap 90 Second control device (control device)

Claims

1. a mounting table on which a recording medium is placed; an ink head having nozzles that eject ink onto the recording medium placed on the mounting table and a nozzle surface on which the nozzles are formed; a first carriage on which the ink head is mounted and which is movable in a main scanning direction; a first sensor for detecting an edge of the recording medium placed on the placement table in the main scanning direction; a second carriage that is detachably attached to the first carriage, has the first sensor mounted thereon, and is movable in the main scanning direction; a carriage moving mechanism that moves the second carriage in the main scanning direction; a control device connected to the first sensor; another control device that controls the ink head and the carriage moving mechanism; a linear encoder including a linear scale extending in the main scanning direction and a second sensor provided on the second carriage and configured to measure the graduations of the scale; the second sensor is connected to the control device; The control device is provided on the second carriage.

2. 2. The inkjet printer according to claim 1, wherein the linear encoder further comprises a third sensor provided on the first carriage and configured to measure the graduations of the scale.

Images