Liquid printing device

Abstract

To prevent a situation in which drive control of a carriage becomes difficult due to an occurrence of an overcurrent request, while preventing a decrease in print quality and improving printing efficiency.SOLUTION: A printer 1 includes a conveyance mechanism 20, an ink jet head 31, an ink tank 61 storing ink, a carriage 70 supporting the ink jet head 31 and the ink tank 61, a scanning mechanism 71, a remaining amount detection unit 80, and a control unit 40. The control unit 40 controls the scanning mechanism 71 so that a scanning stop position of the carriage 70 in the scanning direction in a passing operation is a position separated in the scanning direction (the sideways direction) from a printing area (a first printing area 100a or a second printing area 100b) in the passing operation or the subsequent passing operation as an amount of ink remaining in the ink tank 61 detected by the remaining amount detection unit 80 increases.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid printing apparatus that determines a scanning stop position of a carriage with reference to the weight of a head.

Background Art

[0002] A liquid printing apparatus having an on-carriage configuration in which a print head for discharging ink to perform printing on a sheet and an ink tank (liquid storage unit) for storing ink are mounted on a carriage is known. In such a liquid printing apparatus having an on-carriage configuration, the weight and the center of gravity position of the aggregate of the print head and the ink tank mounted on the carriage change depending on the remaining amount of ink stored in the ink tank. When the weight and the center of gravity position of the aggregate change, the head posture during printing and the amount of current required for accelerating the carriage fluctuate, so that there is a risk that the carriage cannot be appropriately controlled.

[0003] For example, Patent Document 1 discloses an inkjet recording apparatus (liquid printing apparatus) that controls a motor for driving a carriage to keep the landing position of ink constant according to the remaining amount of ink in an ink tank. According to this configuration, even when the remaining amount of ink in the ink tank decreases, the drive data used by the driving motor can be made appropriate according to the remaining amount of ink, and a good image can be formed with the landing position of the ink kept constant regardless of the remaining amount of ink in the ink tank.

[0004] Further, the inkjet printer (liquid printing apparatus) disclosed in Patent Document 2 corrects the position at which a braking voltage starts to be applied to a carrier driving motor according to a correction value of the stop position of a carrier (carriage). Thereby, fluctuations in the stop position of the carrier accompanying fluctuations in the remaining amount of ink can be reduced, and the accuracy of the stop position of the carrier can be improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, in the apparatuses disclosed in Patent Documents 1 and 2 above, when performing a printing operation, when accelerating a stationary carriage until the print head reaches the printing start position, the print head may not return to an appropriate posture. Then, when the carriage is moving at a constant speed from the printing start position through the printing area, ink may not be ejected from the print head at an appropriate position, and there is a risk that the printing quality may deteriorate.

[0007] Also, when the weight of the aggregate increases, an excessively large current that the apparatus cannot tolerate may be required when the carriage is accelerating or decelerating. In this case, the drive control of the carriage cannot be appropriately performed. To avoid this, it may be considered to set the moving distance of the carriage during acceleration and deceleration to be longer. However, in this case, regardless of the magnitude of the weight of the aggregate, since the moving distance of the carriage is long, the printing efficiency decreases.

[0008] An object of the present invention is to provide a liquid printing apparatus that can suppress a decrease in printing quality and improve printing efficiency, while suppressing the occurrence of an overcurrent requirement that makes it difficult to control the drive of the carriage. [Means for Solving the Problems]

[0009] The liquid printing apparatus according to the present invention includes a conveyance mechanism that conveys a recording medium in a conveyance direction, a printing head that performs printing by discharging liquid onto the recording medium in a printing area from a printing start position to a printing end position along a scanning direction that intersects the conveyance direction, a liquid storage unit that stores the liquid, a carriage that supports the printing head and the liquid storage unit, a scanning mechanism that executes a path operation of moving the carriage from a scanning start position to a scanning stop position along the scanning direction, a remaining amount detection unit that detects a remaining amount of the liquid stored in the liquid storage unit, and a control unit. The control unit controls the scanning mechanism such that the scanning stop position of the carriage in the scanning direction in the path operation is a position away from the printing area in the path operation or the next path operation as the remaining amount of the liquid in the liquid storage unit detected by the remaining amount detection unit is larger.

Effect of the Invention

[0010] According to the liquid printing apparatus of the present invention, the larger the remaining amount of the liquid in the liquid storage unit is, the scanning stop position of the carriage in the path operation is set to a position away from the printing area. For this reason, it is possible to suppress a decrease in printing quality and improve printing efficiency, and suppress a situation where an overcurrent requirement occurs and it becomes difficult to control the driving of the carriage.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0012] The printer 1 (the liquid printing apparatus of the present invention) according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5. Note that the vertical direction, the left - right direction, and the front - rear direction shown in FIG. 1 are defined as the vertical direction, the left - right direction, and the front - rear direction of the printer 1, respectively.

[0013] (Configuration of Printer 1) The printer 1 has a substantially rectangular parallelepiped housing 11. An opening 12 is formed in the front surface of the housing 11. An operation unit 13 is provided on the upper surface of the housing 11 (see FIG. 2). The operation unit 13 is composed of buttons operated for various settings, a liquid crystal display on which various information is displayed, and the like. In the present embodiment, the operation unit 13 is composed of buttons operated for various settings. The operation unit 13 may be composed of a touch panel having the functions of both a button and a liquid crystal display.

[0014] As shown in FIG. 1, the printer 1 includes a paper feed tray 15, a paper discharge tray 16, a conveyance mechanism 20, a recording unit 30, a remaining amount detection unit 80 (see FIG. 2), and a control unit 40. The paper feed tray 15, the paper discharge tray 16, the conveyance mechanism 20, the remaining amount detection unit 80, and the control unit 40 are housed in the housing 11.

[0015] The paper feed tray 15 can support and accommodate a plurality of sheets of paper P (the recording medium of the present invention) in a stacked state. The paper feed tray 15 is configured to be insertable and removable in the front - rear direction from the opening 12, that is, detachable from the housing 11. An inclined plate 15a is provided at the rear end of the paper feed tray 15. The inclined plate 15a guides the paper P placed on the paper feed tray 15 to a conveyance path 52 (described later) when the paper P is fed by a paper feed roller 50a (described later).

[0016] The paper discharge tray 16 accommodates the paper P on which an image has been printed by an inkjet head 31 (described later) of the recording unit 30. The paper discharge tray 16 is disposed above the front side of the paper feed tray 15 and is configured to move along with the insertion and removal of the paper feed tray 15 with respect to the housing 11.

[0017] The transport mechanism 20 includes a paper feed unit 50, a transport path 52, a transport roller pair 53, and a paper discharge roller pair 54. As shown in FIG. 1, the paper feed unit 50 feeds the paper P placed on the paper feed tray 15 to the transport path 52. The transport roller pair 53 transports the paper P fed by the paper feed unit 50 to the recording unit 30. The recording unit 30 has, for example, a configuration of an inkjet recording method and records an image on the paper P transported by the transport roller pair 53. The paper discharge roller pair 54 discharges the paper P recorded by the recording unit 30 to the paper discharge tray 16.

[0018] As shown in FIG. 1, the paper feed unit 50 is provided above the paper feed tray 15. The paper feed unit 50 includes a paper feed roller 50a and an arm 50b. The paper feed roller 50a is rotatably supported at the tip of the arm 50b. The arm 50b is rotatably supported by a support shaft 50c and is urged by a spring or the like to rotate downward so that the paper feed roller 50a contacts the paper feed tray 15. Further, the arm 50b is configured to be retractable upward when attaching and detaching the paper feed tray 15. The paper feed roller 50a is driven to rotate by a paper feed motor 91M (see FIG. 2), and the paper P stacked in the paper feed tray 15 is fed to the transport path 52.

[0019] The transport path 52 is formed in the housing 11 and, as shown in FIG. 1, bends upward from the rear end of the paper feed tray 15 and then to the front side of the printer 1. The paper P fed from the paper feed tray 15 is guided by the transport path 52 to make a U-turn from below to above and reaches the recording unit 30.

[0020] The conveying roller pair 53 has a conveying roller 53a disposed on the lower side and a pinch roller 53b disposed on the upper side. The conveying roller 53a is driven to rotate by a conveying motor 92M (see FIG. 2). The pinch roller 53b rotates along with the rotation of the conveying roller 53a. The conveying roller 53a and the pinch roller 53b cooperate to sandwich the sheet P from above and below, and convey the sheet P to the recording unit 30.

[0021] The paper discharge roller pair 54 has a paper discharge roller 54a disposed on the lower side and an accelerating roller 54b disposed on the upper side. The paper discharge roller 54a is driven to rotate by a paper discharge motor 93M (see FIG. 2). The accelerating roller 54b rotates along with the rotation of the paper discharge roller 54a. The paper discharge roller 54a and the accelerating roller 54b cooperate to sandwich the sheet P from above and below, and convey the sheet P to the paper discharge tray 16.

[0022] In this embodiment, the conveyance direction of the sheet P is the direction in which the sheet P is conveyed from the paper feed tray 15 by the conveyance mechanism 20, which is the direction of the solid arrow in FIG. 1. Specifically, the conveyance direction of the sheet P is sent from the front to the rear by the paper feed roller 50a, guided by the conveyance path 52 to make a U-turn, and further sent from the rear to the front by the conveying roller pair 53 and the paper discharge roller pair 54.

[0023] As shown in Fig. 1, the recording unit 30 includes an inkjet head 31 (printing head of the present invention), four ink tanks 61 (liquid storage units of the present invention), a carriage 70, a scanning mechanism 71, and a platen 17. The carriage 70 reciprocates in the scanning direction (left - right direction, which intersects the conveyance direction of the paper P). The inkjet head 31 and the ink tanks 61 are supported by the carriage 70. That is, the printer 1 in the present embodiment is a so - called on - carriage type in which the ink tanks 61 and the inkjet head 31 are mounted on the carriage 70. In the present embodiment, the entire ink tank 61 is located above the inkjet head 31. However, it is not limited to this, and a part of the ink tank 61 may be located above the upper surface of the inkjet head 31, and the remaining part may be located below the upper surface.

[0024] Each of the four ink tanks 61 stores magenta, cyan, yellow, and black (M, C, Y, B) inks. Each ink tank 61 has a valve 63 for opening and closing an ink injection port (not shown). The valve 63 is, for example, a two - way electromagnetic valve in which a solenoid is driven to move the valve to open and close. When the valve 63 is in the open state, it is possible to inject ink into the ink tank 61 through the ink injection port. When the valve 63 is in the closed state, injecting ink into the ink tank 61 through the ink injection port is restricted.

[0025] The inkjet head 31 has an internal flow path (not shown) through which ink is supplied from the ink tank 61. The inkjet head 31 discharges ink from a plurality of nozzles (not shown) formed on its lower surface. More specifically, the plurality of nozzles form a nozzle row in the front - rear direction along the conveyance direction of the paper P. Ink is discharged from the plurality of nozzles.

[0026] The platen 17 is disposed below the inkjet head 31 and supports the paper P conveyed by the pair of conveyance rollers 53 from below. The platen 17 is disposed in a portion through which the paper P passes within the reciprocating movement range of the carriage 70. Since the width of the platen 17 is sufficiently larger than the maximum width of the paper P that can be conveyed, the paper P conveyed through the conveyance path 52 always passes over the platen 17.

[0027] The scanning mechanism 71 executes a path operation of moving the carriage 70 from the scanning start position to the scanning stop position along the scanning direction (left - right direction). Note that the scanning stop position of the carriage 70 in an arbitrary path operation becomes the scanning start position of the carriage 70 in the next path operation of the arbitrary path operation. The scanning stop position of the carriage 70 in an arbitrary path operation is determined by the control unit 40 described later. In the present embodiment, in the path operation, the carriage 70 reciprocates along the scanning direction. As shown in FIG. 1, the scanning mechanism 71 includes a pair of guide rails 72 and a belt transmission mechanism 73 (see FIG. 4). The pair of guide rails 72 are arranged at intervals in the front - rear direction and extend parallel to each other in the left - right direction. The carriage 70 is arranged so as to straddle the pair of guide rails 72. The carriage 70 is connected to a carriage motor 94M (see FIG. 2) via the belt transmission mechanism 73. When the carriage motor 94M is driven, the belt transmission mechanism 73 is driven. Thereby, the carriage 70 moves in the scanning direction (left - right direction) along the pair of guide rails 72, and the inkjet head 31 is moved in the left - right direction.

[0028] The inkjet head 31 ejects ink from a plurality of nozzles to perform printing on the paper P in a printing area (for example, refer to 100a and 100b in FIG. 3) from the printing start position to the printing end position along the scanning direction (left - right direction) under the control of the control unit 40 based on the recording data. That is, as the carriage 70 reciprocates in the left - right direction, the inkjet head 31 scans the paper P, and by ejecting ink from the nozzles, an image is recorded in the printing area of the paper P conveyed on the platen 17.

[0029] The printing area is the area on the paper P where printing is performed among the moving areas along the scanning direction of the inkjet head 31 in one pass operation. The printing start position is the position where printing on the paper P by the inkjet head 31 starts in the printing area. The printing end position is the position where printing on the paper P by the inkjet head 31 ends in the printing area. In one pass operation, the scanning mechanism 71 accelerates the carriage 70 from the scanning start position to the printing start position. Subsequently, the scanning mechanism 71 moves the carriage 70 at a constant speed in the printing area. Then, the scanning mechanism 71 decelerates the carriage 70 from the printing end position to the scanning stop position. In the present embodiment, the control unit 40 causes the scanning mechanism 71 to execute such a pass operation a plurality of times.

[0030] As described above, in the present embodiment, in one pass operation, the carriage 70 reciprocates along the scanning direction. That is, in the present embodiment, the printing start position and the printing end position in any pass operation are the same position. Note that in the present embodiment, the position where the ejection of ink from the inkjet head 31 is temporarily interrupted in one pass operation is not included in the printing end position.

[0031] Note that a linear encoder (not shown) having a large number of light transmitting portions (slits) arranged at intervals in the scanning direction is provided in the printer 1. On the other hand, a transmissive position detection sensor (not shown) having a light emitting element and a light receiving element is provided on the carriage 70. Then, the printer 1 can recognize the current position of the carriage 70 in the scanning direction from the count value of the light transmitting portion of the linear encoder detected by the position detection sensor during the movement of the carriage 70, and the rotational drive of the carriage motor 94M is controlled.

[0032] The remaining amount detection unit 80 detects the remaining amount of ink stored inside the ink tank 61. The remaining amount detection unit 80 detects the remaining amount of ink stored inside each ink tank 61. In the present embodiment, the remaining amount detection unit 80 is of a sensor arm type including a floating member (not shown) supported at the tip of a swingable arm and an optical sensor (not shown) capable of detecting the position of the floating member inside each ink tank 61. The floating member is a member having a specific gravity smaller than that of the ink stored inside the ink tank 61, and by detecting the position of the floating member with the optical sensor, it is possible to detect the remaining amount of ink inside the ink tank 61. A signal including information on the remaining amount of ink inside the ink tank 61 detected by the remaining amount detection unit 80 is transmitted to the control unit 40. Note that the remaining amount detection unit 80 may constantly detect the remaining amount of ink inside the ink tank 61, or may detect only when a signal for an ink replenishment instruction is input to the control unit 40 at the time of ink replenishment.

[0033] The control unit 40 includes a CPU (Central Processing Unit) 131, an ASIC (Application Specific Integrated Circuit) 135, and a memory 140. These CPU 131, ASIC 135, and memory 140 are connected by an internal bus 137. The memory 140 includes a ROM (Read Only Memory) 132, a RAM (Random Access Memory) 133, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 134. Programs for controlling various operations of the printer 1 and the like are stored in the ROM 132. The CPU 131 executes programs while using the RAM 133 and the EEPROM 134.

[0034] ASIC 135 outputs control signals to the inkjet head 31, the valve 63, the paper feed motor 91M, the conveyance motor 92M, the paper discharge motor 93M, the carriage motor 94M, etc., and controls these operations. For example, based on the recording data transmitted from an external device (e.g., a PC or a smartphone), the control unit 40 controls the inkjet head 31, the paper feed motor 91M, the conveyance motor 92M, the paper discharge motor 93M, the carriage motor 94M, etc., to alternately execute a conveyance process and a recording process, and record an image or the like on the paper P. Further, ASIC 135 can receive signals transmitted from the operation unit 13, signals transmitted from the remaining amount detection unit 80, etc.

[0035] (Drive control of the carriage 70 by the scanning mechanism 71) Subsequently, with reference to FIGS. 3 to 5, an example of the control performed by the control unit 40 when the drive control of the carriage 70 is performed by the scanning mechanism 71 in the printer 1 will be described. In the following description, as shown in FIG. 3, the printing area in an arbitrary pass operation is defined as the first printing area 100a, and the printing area in the pass operation next to the arbitrary pass operation is defined as the second printing area 100b.

[0036] First, when the scanning mechanism 71 executes an arbitrary pass operation, the control unit 40 acquires the first stop position L1 that is separated from the printing start position S2 of the second printing area 100b in the next pass operation by the acceleration distance rx. Further, when the scanning mechanism 71 executes an arbitrary pass operation, the control unit 40 acquires the second stop position L2 that is separated from the printing end position E1 of the first printing area 100a in the arbitrary pass operation by the deceleration distance ry.

[0037] The acceleration distance rx is a distance that becomes larger as the ink remaining amount inside the ink tank 61 detected by the remaining amount detection unit 80 is larger. Further, the acceleration distance rx is a distance necessary to make the carriage 70 have the operation speed in the second printing area 100b when the carriage 70 stopped at the first stop position L1 starts accelerating and reaches the printing start position S2 of the second printing area 100b. The operation speed is, for example, a preset constant speed.

[0038] Further, the acceleration distance rx is the distance required to make the posture of the inkjet head 31 the ideal printing posture in the second printing area 100b while the carriage 70 moves from the first stop position L1 to the printing start position S2. The ideal printing posture is a posture in which ink can be ejected from the inkjet head 31 to an appropriate position on the paper P when the carriage 70 is moving in the second printing area 100b at the above-described operating speed.

[0039] Hereinafter, the ideal printing posture will be described in detail. As shown in FIG. 4, the carriage 70 on which the inkjet head 31 and the ink tank 61 are mounted is supported by a belt transmission mechanism 73 via a spring member 74. When the posture of the carriage 70 including the inkjet head 31 is inclined, a force in the direction of returning the inkjet head 31 to the ideal printing posture acts on the carriage 70 from the spring member 74. On the other hand, when the carriage 70 is accelerating in the scanning direction, a force that tends to incline the inkjet head 31 from the ideal printing posture acts on the carriage 70. The force acting due to the acceleration of the carriage 70 increases as the acceleration increases. When the force acting due to the acceleration of the carriage 70 is large, the carriage 70 may incline in the scanning direction when viewed from the front-rear direction (see the solid arrow in FIG. 4), or may incline in the front-rear direction when viewed from the up-down direction (see the solid arrow in FIG. 5). In this case, the inkjet head 31 cannot be set to the ideal printing posture, and the printing quality may deteriorate.

[0040] For example, when the carriage 70 stopped at the first stop position L1 is rapidly accelerated over a short distance to the operating speed in the second printing area 100b, the inclination of the inkjet head 31 increases. Further, for the carriage 70 that has reached the operating speed, if the length of the distance to be moved at a constant speed until reaching the printing start position S2 is insufficient, the inkjet head 31 cannot be brought into the ideal printing posture by the force acting from the spring member 74 while the carriage 70 reaches the printing start position S2. Therefore, considering the magnitude of the force acting from the spring member 74 and the force acting during the acceleration of the carriage 70, the acceleration distance rx is defined as the distance that allows the carriage 70 to reach the printing start position S2 from the first stop position L1 without sudden acceleration and with sufficient distance for moving at a constant speed necessary to make the posture of the inkjet head 31 the ideal printing posture. Note that the force acting due to the acceleration of the carriage 70 increases as the ink remaining amount in the ink tank 61 is larger, that is, as the weight of the carriage 70 is larger. Further, the more the center of gravity position of the carriage 70, which is determined by the ink remaining amount in each ink tank 61, is offset, the more likely the carriage 70 is to incline. Therefore, it is preferable that the acceleration distance rx is set in consideration of the weight and the center of gravity position of the carriage 70 determined by the ink remaining amount in the ink tank 61.

[0041] Further, the acceleration distance rx is the distance necessary to make the carriage 70 reach the operating speed in the second printing area 100b at the printing start position S2 when the carriage 70 at the first stop position L1 is accelerated by supplying the maximum allowable current to the scanning mechanism 71. The maximum allowable current is the maximum current that can be supplied to the scanning mechanism 71 and is preset, for example.

[0042] The deceleration distance ry is a distance that becomes larger as the ink remaining amount inside the ink tank 61 detected by the remaining amount detection unit 80 is larger. Further, the deceleration distance ry is a distance necessary to stop the carriage 70 at the operating speed in the first printing area 100a. Furthermore, the deceleration distance ry is a distance necessary to stop the carriage 70 at the second stop position L2 when the carriage 70 at the printing end position E1 in the first printing area 100a is decelerated by supplying the maximum allowable current to the scanning mechanism 71.

[0043] In addition, in the present embodiment, it is preferable that the acceleration distance rx is the minimum value within the range that satisfies the above-described conditions. Also, it is preferable that the deceleration distance ry is the minimum value within the range that satisfies the above-described conditions. That is, within the range where the acceleration and deceleration of the carriage 70 can be appropriately performed, it is preferable that the first stop position L1 is as close as possible to the printing start position S2, and the second stop position L2 is as close as possible to the printing end position E1. Thereby, since it is not necessary to make the moving distance of the carriage 70 longer than necessary, the printing efficiency can be improved.

[0044] Subsequently, the control unit 40 controls the scanning mechanism 71 so that the position farther from the second printing area 100b in the lateral direction in the next pass operation among the first stop position L1 and the second stop position L2 becomes the scanning stop position of the carriage 70 in the scanning direction (lateral direction) in an arbitrary pass operation. For example, as shown in FIG. 3, when the first stop position L1 is farther from the second printing area 100b than the second stop position L2, the scanning stop position of the carriage 70 in an arbitrary pass operation for performing printing in the first printing area 100a is the first stop position L1.

[0045] Also, when printing on the paper P by the inkjet head 31 is not performed in the next pass operation of an arbitrary pass operation, the control unit 40 sets the scanning stop position of the carriage 70 in the arbitrary pass operation to the second stop position L2. In this case, the control unit 40 does not compare which of the first stop position L1 and the second stop position is farther from the second printing area 100b in the next pass operation.

[0046] As described above, the printer 1 of the present embodiment includes a transport mechanism 20, an inkjet head 31, an ink tank 61 that stores ink, a carriage 70 that supports the inkjet head 31 and the ink tank 61, a scanning mechanism 71, a remaining amount detection unit 80, and a control unit 40. The control unit 40 controls the scanning mechanism 71 such that the scanning stop position of the carriage 70 in the scanning direction in the pass operation is a position away from the printing area in the scanning direction (left - right direction) in the current pass operation or the next pass operation as the ink remaining amount in the ink tank 61 detected by the remaining amount detection unit 80 increases. According to the present embodiment, as the ink remaining amount in the ink tank 61 increases, the scanning stop position of the carriage 70 in the pass operation is set to a position away from the printing area. Therefore, it is possible to suppress a decrease in printing quality and improve printing efficiency, and suppress a situation where an over - current requirement occurs and the drive control of the carriage 70 becomes difficult.

[0047] Further, in the present embodiment, the control unit 40 acquires a first stop position L1 that is separated from the printing start position S2 in the next pass operation of an arbitrary pass operation by an acceleration distance rx, and a second stop position L2 that is separated from the printing end position E1 in an arbitrary pass operation by a deceleration distance ry. The acceleration distance rx is a distance that increases as the ink remaining amount in the ink tank 61 increases, and is the distance required to make the carriage 70 have the operation speed in the second printing area 100b when the carriage 70 is at the printing start position S2 in the next pass operation. The deceleration distance ry is a distance that increases as the ink remaining amount in the ink tank 61 increases, and is the distance required to stop the carriage 70 having the operation speed in the first printing area 100a. Then, the control unit 40 controls the scanning mechanism 71 such that the position that is farther away from the second printing area 100b in the next pass operation among the first stop position L1 and the second stop position L2 becomes the scanning stop position of the carriage 70 in the scanning direction in an arbitrary pass operation.

[0048] According to the above configuration, among the first stop position L1 and the second stop position L2, the position farther from the printing area in the next pass operation can be set as the scanning stop position of the carriage 70 in any pass operation. For this reason, in any pass operation and the next pass operation, it is possible to surely secure both the acceleration distance rx and the deceleration distance ry of the carriage 70, which become larger as the remaining ink amount in the ink tank 61 increases. Thereby, a further reduction in print quality can be suppressed.

[0049] Also, in the present embodiment, the acceleration distance rx is the distance required to make the posture of the inkjet head 31 the ideal printing posture in the second printing area 100b in the next pass operation from the first stop position L1 to the printing start position S2 in the next pass operation. According to the present embodiment, the scanning stop position of the carriage 70 in any pass operation can be set as a position where the posture of the inkjet head 31 becomes the ideal printing posture at the printing start position S2 in the next pass operation. Thereby, when the carriage 70 moves from the printing start position S2 to the second printing area 100b, ink can be ejected from the inkjet head 31 to an appropriate position, and a reduction in print quality can be more surely suppressed.

[0050] Furthermore, in the present embodiment, the acceleration distance rx is the distance required to set the carriage 70 to the operating speed at the printing start position S2 when the carriage 70 at the first stop position L1 is accelerated by supplying the maximum allowable current to the scanning mechanism 71. According to the present embodiment, when accelerating the carriage so that the carriage 70 reaches the operating speed at the printing start position S2, it is possible to prevent the current supplied to the scanning mechanism 71 from exceeding the maximum allowable current. For this reason, it is possible to further suppress the occurrence of an overcurrent requirement and the difficulty of driving control of the carriage 70.

[0051] Also, in the present embodiment, the deceleration distance ry is the distance required to stop the carriage 70 at the second stop position L2 when the carriage 70 at the printing end position E1 is decelerated by supplying the maximum allowable current to the scanning mechanism 71. According to the present embodiment, when decelerating the carriage 70 from the printing end position E1 to stop the carriage 70, the current supplied to the scanning mechanism 71 can be prevented from exceeding the maximum allowable current. Therefore, it is possible to further suppress the occurrence of an overcurrent requirement and the difficulty of driving control of the carriage 70.

[0052] Also, in the present embodiment, when printing on the paper P by the inkjet head 31 is not performed in the next pass operation after an arbitrary pass operation, the control unit 40 controls the scanning mechanism 71 so that the scanning stop position of the carriage 70 in the arbitrary pass operation becomes the second stop position L2. When printing by the inkjet head 31 is not performed in the next pass operation, it is not necessary to consider the acceleration distance rx of the carriage 70 in the next pass operation when determining the scanning stop position of the carriage 70. According to the present embodiment, when printing by the inkjet head 31 is not performed in the next pass operation, the scanning stop position of the carriage 70 can be determined in consideration of only the deceleration distance ry determined by the remaining ink amount in the ink tank 61. Therefore, the drive control of the carriage 70 is easy.

[0053] (Modification example) As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible as long as they are within the scope described in the patent invention.

[0054] In the present invention, the control unit 40 may determine the scanning stop position of the carriage 70 based on a comparison between the ink remaining amount in the ink tank 61 detected by the remaining amount detection unit 80 and at least one threshold value. A predetermined threshold value, the scanning stop position when the ink remaining amount in the ink tank 61 is equal to or greater than the predetermined threshold value, and the scanning stop position when it is less than the predetermined threshold value are set in advance. For example, as shown in FIG. 6, in an arbitrary pass operation, when the ink remaining amount in the ink tank 61 is equal to or greater than the predetermined threshold value, the control unit 40 controls the scanning mechanism 71 so that the scanning stop position of the carriage 70 becomes a preset scanning stop position L11. Further, as shown in FIG. 6, in an arbitrary pass operation, when the ink remaining amount in the ink tank 61 is less than the predetermined threshold value, the control unit 40 controls the scanning mechanism 71 so that the scanning stop position of the carriage 70 becomes a preset scanning stop position L12. As shown in FIG. 6, the scanning stop position L11 is a position farther from the second printing area 100b in the next pass operation or the first printing area 100a in an arbitrary pass operation than the scanning stop position L12. The predetermined threshold value may be one or a plurality. According to the above configuration, the scanning stop position can be easily determined by comparing the ink remaining amount in the ink tank 61 with the threshold value.

[0055] In the present invention, even when printing on the paper P by the inkjet head 31 is not performed in the next pass operation of an arbitrary pass operation, the control unit 40 may control the scanning mechanism 71 so that the scanning stop position of the carriage 70 in the arbitrary pass operation becomes a stop position other than the second stop position L2. For example, when the next operation of an arbitrary pass operation is an ink replenishment operation or an ink disposal operation, the scanning stop position of the carriage 70 in the arbitrary pass operation may be determined in consideration of the position where the operation is performed.

[0056] In the present invention, the liquid storage unit may be a cartridge. Further, the liquid printing apparatus according to the present invention can be applied not only to the printer 1 but also to a multifunction device, a copying machine, and the like.

[0057] In the above embodiment, the remaining amount detection unit 80 is of the sensor arm type. However, the remaining amount detection unit 80 may also be of the prism type. In the case of the remaining amount detection unit 80 of the prism type, the ink tank 61 is made of resin. And the remaining amount detection unit 80 includes an infrared irradiation unit that irradiates infrared rays from the outside to the inside of the ink tank 61, and an infrared light receiving unit that detects the infrared rays reflected by the resin-made ink tank 61. When there is ink in the portion of the ink tank 61 irradiated with infrared rays, the infrared rays irradiated from the infrared irradiation unit travel straight through the interface between the resin and the ink. At this time, the infrared light receiving unit does not detect the infrared rays. On the other hand, when there is no ink in the portion of the ink tank 61 irradiated with infrared rays, the infrared rays irradiated from the infrared irradiation unit are totally reflected at the interface between the resin and the air and are detected by the infrared light receiving unit. By arranging one or more of the infrared irradiation unit and the infrared light receiving unit at an arbitrary position with respect to the ink tank 61, the remaining amount of ink in the ink tank 61 can be detected.

[0058] Also, the remaining amount detection unit 80 may be of the soft count type. In this case, the remaining amount detection unit 80 includes a counting unit that counts a value related to the amount of ink ejected from the nozzles of the inkjet head 31, and a calculating unit that calculates the remaining amount of ink stored in the ink tank 61 based on the value related to the amount of ink counted by the counting unit. For example, the calculating unit calculates, as the remaining amount of ink in the ink tank 61, a value obtained by subtracting the amount of ink ejected from the nozzles from the remaining amount of ink in the ink tank 61 immediately after the printer 1 is shipped or immediately after ink replenishment to the ink tank 61. The calculated value is always overwritten and stored in the EEPROM 134. The remaining amount of ink in the ink tank 61 immediately after ink replenishment to the ink tank 61 is calculated, for example, by adding the value of the replenished ink amount to the value of the remaining amount of ink in the ink tank 61 before ink replenishment.

[0059] In the present invention, any pass operation and the next pass operation after any pass operation may be performed on different sheets of paper P. Also, in the present invention, in one pass operation, the carriage 70 may move one-way along the scanning direction. In this case, one side in the scanning direction of the printing area in any pass operation becomes the printing start position, and the other side becomes the printing end position.

Explanation of Signs

[0060] 1 Printer 20 Conveying mechanism 31 Inkjet head (printing head) 40 Control unit 61 Ink tank (liquid storage section) 70 Carriage 71 Scanning mechanism 80 Remaining amount detection unit 100a First printing area (printing area) 100b Second printing area (printing area) E1 Printing end position L1 First stop position L2 Second stop position rx Acceleration distance ry Deceleration distance S2 Printing start position P Sheet of paper

Claims

1. A conveyance mechanism for conveying a recording medium in a conveyance direction; A printing head that performs printing by discharging a liquid onto the recording medium in a printing area from a printing start position to a printing end position along a scanning direction that intersects the conveyance direction; A liquid storage unit for storing the liquid; A carriage that supports the printing head and the liquid storage unit; A scanning mechanism that executes a path operation for moving the carriage from a scanning start position to a scanning stop position along the scanning direction; A remaining amount detection unit that detects a remaining amount of the liquid stored in the liquid storage unit; A control unit, and the control unit controls the scanning mechanism such that the scanning stop position of the carriage in the scanning direction in the path operation is a position farther from the printing area in the path operation or the next path operation as the remaining amount of the liquid in the liquid storage unit detected by the remaining amount detection unit is larger; the control unit a first stop position that is a distance that becomes larger as the remaining amount of the liquid in the liquid storage unit is larger from the printing start position in the next path operation after an arbitrary path operation, and is a distance away from the printing start position in the next path operation by an acceleration distance necessary to make the carriage have an operation speed in the printing area when the carriage is at the printing start position in the next path operation; a second stop position that is a distance that becomes larger as the remaining amount of the liquid in the liquid storage unit is larger from the printing end position in the arbitrary path operation, and is a distance away from the printing end position in the arbitrary path operation by a deceleration distance necessary to stop the carriage having the operation speed; and obtains the first stop position and the second stop position, the control unit controls the scanning mechanism such that the position that is farther from the printing area in the next path operation among the first stop position and the second stop position becomes the scanning stop position of the carriage in the scanning direction in the arbitrary path operation; the acceleration distance is a distance necessary to make the posture of the printing head an ideal printing posture in the printing area in the next path operation between the first stop position and the printing start position in the next path operation, and The ideal printing posture is the posture of the print head that can eject liquid from the print head to an appropriate position on the recording medium when the carriage is moving at the operation speed in the printing area. The acceleration distance is the distance required to set the carriage at the operation speed at the printing start position when the carriage at the first stop position is accelerated by supplying the maximum allowable current to the scanning mechanism. A liquid printing apparatus characterized by this.

2. A conveyance mechanism that conveys a recording medium in the conveyance direction, A print head that ejects liquid onto the recording medium in a printing area from a printing start position to a printing end position along a scanning direction intersecting the conveyance direction to perform printing, A liquid storage unit that stores liquid, A carriage that supports the print head and the liquid storage unit, A scanning mechanism that executes a path operation of moving the carriage from a scanning start position to a scanning stop position along the scanning direction, A remaining amount detection unit that detects the remaining amount of the liquid stored in the liquid storage unit, A control unit, and is provided with The control unit controls the scanning mechanism so that the scanning stop position of the carriage in the scanning direction in the path operation is a position away from the printing area in the path operation or the next path operation as the remaining amount of the liquid in the liquid storage unit detected by the remaining amount detection unit is larger. The control unit From the printing start position in the next path operation of an arbitrary path operation, a distance that becomes larger as the remaining amount of the liquid in the liquid storage unit is larger, and when the carriage is at the printing start position in the next path operation, the carriage is at the operation speed in the printing area. A first stop position separated by the required acceleration distance, From the printing end position in the arbitrary path operation, a second stop position separated by a deceleration distance required to stop the carriage at the operation speed, which is a distance that becomes larger as the remaining amount of the liquid in the liquid storage unit is larger, are acquired. Controlling the scanning mechanism such that, among the first stop position and the second stop position, the position farther from the printing area in the next pass operation is the scanning stop position of the carriage in the scanning direction in the arbitrary pass operation; The acceleration distance is a distance required to set the carriage at the printing start position to the operation speed when accelerating the carriage at the first stop position by supplying the maximum allowable current to the scanning mechanism. A liquid printing apparatus characterized by this.

3. A conveyance mechanism for conveying a recording medium in a conveyance direction; A printing head that performs printing by discharging liquid onto the recording medium in a printing area from a printing start position to a printing end position along a scanning direction intersecting the conveyance direction; A liquid storage unit for storing liquid; A carriage that supports the printing head and the liquid storage unit; A scanning mechanism that executes a pass operation of moving the carriage from a scanning start position to a scanning stop position along the scanning direction; A remaining amount detection unit that detects the remaining amount of the liquid stored in the liquid storage unit; A control unit, and is provided with: The control unit controls the scanning mechanism such that the larger the remaining amount of the liquid in the liquid storage unit detected by the remaining amount detection unit, the farther the scanning stop position of the carriage in the scanning direction in the pass operation is from the printing area in the pass operation or the next pass operation; The control unit is From the printing start position in the next pass operation of an arbitrary pass operation, a distance that becomes larger as the remaining amount of the liquid in the liquid storage unit is larger, and when the carriage is at the printing start position in the next pass operation, the carriage is separated by an acceleration distance required to set the operation speed in the printing area. A first stop position; Obtain a second stop position that is at a distance that increases as the remaining amount of liquid in the liquid storage unit increases from the printing end position in the arbitrary pass operation, and is separated by a deceleration distance necessary to stop the carriage at the operating speed, Control the scanning mechanism so that the position farther from the printing area in the next pass operation among the first stop position and the second stop position becomes the scanning stop position of the carriage in the scanning direction in the arbitrary pass operation, The deceleration distance is a distance necessary to stop the carriage at the second stop position when the maximum allowable current is supplied to the scanning mechanism to decelerate the carriage at the printing end position. A liquid printing apparatus characterized by this.

4. The acceleration distance is a distance necessary to make the posture of the print head the ideal printing posture in the printing area in the next pass operation from the first stop position to the printing start position in the next pass operation. The liquid printing apparatus according to claim 2 or 3, characterized by this.

5. The acceleration distance is a distance necessary to make the carriage reach the operating speed at the printing start position when the maximum allowable current is supplied to the scanning mechanism to accelerate the carriage at the first stop position. The liquid printing apparatus according to claim 3 or 4, characterized by this.

6. The deceleration distance is a distance necessary to stop the carriage at the second stop position when the maximum allowable current is supplied to the scanning mechanism to decelerate the carriage at the printing end position. The liquid printing apparatus according to any one of claims 1, 2, 4, or 5, characterized by this.

7. The control unit, When printing on the recording medium by the print head is not performed in the next pass operation of an arbitrary pass operation, control the scanning mechanism so that the scanning stop position of the carriage in the arbitrary pass operation becomes the second stop position. The liquid printing apparatus according to any one of claims 1 to 6, characterized by this.

8. The control unit determines the scanning stop position of the carriage based on a comparison between the remaining amount of liquid in the liquid storage unit detected by the remaining amount detection unit and at least one threshold value. The liquid printing apparatus according to any one of claims 1 to 7.

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