Recording device and control method

Abstract

This technology provides a way to suppress the increase in the time required for recording. [Solution] The device includes a carriage mounted on a recording head and movable in a width direction intersecting the transport direction of the recording medium, a first detection means provided on one side of the carriage in the width direction and capable of detecting the edge of the recording medium, and a second detection means provided on the other side of the carriage in the width direction and capable of detecting the edge of the recording medium, wherein at least one of the first detection means and the second detection means includes a light-emitting means for irradiating a platen supporting the recording medium and the recording medium with light, a first light-receiving means capable of receiving reflected light from the platen supporting the recording medium and the recording medium, and a second light-receiving means provided overlapping the first light-receiving means in the transport direction and spaced apart in the width direction, and capable of receiving reflected light from the platen supporting the recording medium and the recording medium.

Description

Technical Field

[0001] The present disclosure relates to a recording apparatus and a control method.

Background Art

[0002] In a recording apparatus that ejects ink by an inkjet method and records on a recording medium, when performing seamless recording without providing a margin at the end of the recording medium, if the detection accuracy of the end position of the recording medium is low, it will induce contamination inside the apparatus and the occurrence of margins. Patent Document 1 discloses a technique for detecting the end position of a recording medium based on a detection signal generated according to the reflected light from the recording medium using a single detection unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique of Patent Document 1, when detecting both ends of the recording medium in the scanning direction by a detection unit provided on one side in the scanning direction of the recording head, it is necessary to widen the scanning range, which increases the time required for recording.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a technique capable of suppressing an increase in the time required for recording.

Means for Solving the Problems

[0006] To achieve the above objective, one embodiment of the recording apparatus according to the present disclosure comprises: a support means for supporting a recording medium to be transported; a carriage mounted on a recording head for ejecting ink onto the recording medium and movable in the width direction of the recording medium intersecting the transport direction of the recording medium; a first detection means provided on one side of the carriage in the width direction and capable of detecting the edge of the recording medium in the width direction; and a second detection means provided on the other side of the carriage in the width direction and capable of detecting the edge of the recording medium in the width direction, wherein at least one of the first detection means and the second detection means comprises: a light-emitting means for irradiating the support means and the recording medium supported by the support means with light; a first light-receiving means capable of receiving reflected light from the support means and the recording medium supported by the support means; and a second light-receiving means provided with respect to the first light-receiving means, overlapping in the transport direction and spaced apart in the width direction, and capable of receiving reflected light from the support means and the recording medium supported by the support means. [Effects of the Invention]

[0007] This disclosure makes it possible to suppress the increase in the time required for recording. [Brief explanation of the drawing]

[0008] [Figure 1] Perspective view of the recording device. [Figure 2] A schematic diagram of the recording unit. [Figure 3] Schematic diagram of the first and second sensors. [Figure 4] A block diagram focusing on the configuration of the control system of the recording device. [Figure 5] A diagram illustrating the change in the output voltage of the first sensor. [Figure 6] This figure shows the output waveform indicating the change in the output voltage of the first sensor. [Figure 7] A diagram illustrating the operation of the second sensor in differential mode. [Figure 8]A diagram for explaining the output voltage at one of the light-receiving parts of the second sensor in differential mode. [Figure 9] A diagram showing an output waveform indicating the change in the differential signal in differential mode. [Figure 10] A diagram showing the change in the output voltage of the second sensor in single mode. [Figure 11] A flowchart showing the details of the recording process. [Figure 12] A diagram for explaining the detection of the end position of the recording medium during scanning with recording. [Figure 13] A diagram showing an overview of the determination of the end position of the recording medium. [Figure 14] A flowchart showing the details of the acquisition process. [Figure 15] A diagram showing the size of the recording image with respect to the recording medium in micro margin recording. [Figure 16] A diagram for explaining the change in the moving speed of the first sensor when passing through the end. [Figure 17] A diagram for explaining an overview of the change in the stop position of the carriage. [Figure 18] A flowchart showing the details of the change process. [Figure 19] A flowchart showing the details of a modification example of the change process. [Figure 20] A diagram for explaining the condition under which no change occurs in the moving speed in a scanning unit with recording. [Figure 21] A diagram showing an example of data indicating the relationship between the difference in moving speed and the correction amount. [Figure 22] A diagram for explaining the detection technique of the end position of the recording medium according to unnecessary output. [Figure 23] A diagram for explaining the detection technique of the end position of the recording medium according to unnecessary output. [Figure 24] A diagram for explaining the detection technique of the end position of the recording medium according to unnecessary output. [Figure 25] A diagram for explaining the detection technique of the end position of the recording medium according to abnormal output.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an example of an embodiment of the recording device and control method will be described in detail with reference to the attached drawings. Note that the following embodiment is not intended to limit the present disclosure, and not all combinations of features described in this embodiment are essential to the solutions of this disclosure. Furthermore, the positions and shapes of the components described in the embodiment are merely illustrative and are not intended to limit the scope of this disclosure to them alone.

[0010] (First Embodiment) First, the recording device according to the first embodiment will be described in detail with reference to Figures 1 to 12.

[0011] <Recording device configuration> Figure 1 is a perspective view of the recording device. Figure 2 is a schematic diagram showing the configuration of the recording section located inside the recording device, where (a) is a plan view and (b) is a front view. In this specification, when facing the side from which the recorded recording medium is ejected after recording, the direction from the right side of the recording device to the left side is described as the X direction, the direction from the back side (rear side) of the recording device to the front side (front side) is described as the Y direction, and the direction from the bottom side of the recording device to the top side is described as the Z direction. Thus, the X, Y, and Z directions are directions from one side to the other and are mutually orthogonal. In this specification, each direction is indicated with a "+" (plus) sign when it is going from one side to the other, and with a "-" (minus) sign when it is going from the other side to the one side.

[0012] The recording device 10 shown in Figure 1 houses a recording unit 30 (see Figure 2) within a housing 14 (see Figure 1) that records data by ejecting ink from a recording head 12 (see Figure 2) onto a transported recording medium M. The recording device 10 has an operation unit 16 on its front that displays various information and accepts user operations, a notification unit 18 that provides voice notifications, and an ejection unit 20 from which the recording medium M is ejected after recording. The recording device 10 also has a roll holding unit 22 on its rear side that holds a roll formed by winding a sheet-like recording medium M and can unwind the roll to feed the recording medium M to the recording unit 30. Furthermore, the recording device 10 has a sheet feeding unit 24 that can feed a cut sheet-like recording medium M of a predetermined size to the recording unit 30. In addition, the recording device 10 has an ink tank 26 that stores ink supplied to the recording head 12 and a housing unit 28 that houses a waste liquid tank (not shown) that stores waste ink.

[0013] The recording device 10 includes a recording unit 30 located within the housing 14, which transports the recording medium M fed from the roll holding unit 22 and the sheet feeding unit 24 to a position where it can be recorded by the recording head 12, and discharges the recorded recording medium M from the discharge unit 20. Various known technologies can be used as the transport mechanism, such as a configuration in which the recording medium M is nipped by a drive roller and a driven roller that is pressed against and driven by the drive roller, and the nipped recording medium M is transported by the drive of the drive roller. In this embodiment, the recording medium M is transported in the +Y direction.

[0014] The recording unit 30 is equipped with a carriage 32 on which a recording head 12 is mounted and which is capable of reciprocating in the X direction (see Figure 2). The carriage 32 is slidably mounted on a guide rail (not shown) extending in the X direction and is configured to move in the X direction from one side to the other (+X direction) and from the other side to the one side (-X direction) by the drive of a carriage motor 410 (see Figure 4). Therefore, in the recording device 10, the recording head 12 mounted on the carriage 32 is also capable of reciprocating in the X direction via the carriage 32.

[0015] The recording unit 30 includes a recording head 12 that moves via a carriage 32 and a platen 34 that supports the conveyed recording medium M at an opposing position. In this embodiment, the platen 34 functions as a support for the conveyed recording medium M. In the recording unit 30, the recording head 12 ejects ink from the recording medium M, which is conveyed in the +Y direction (conveying direction) and supported by the platen 34, while moving in the width direction (±X direction) of the recording medium M via the carriage 32. In this embodiment, the platen 34 has the characteristic of absorbing irradiated light and not reflecting, or reflecting, the light. The recording head 12 has a nozzle row 12a formed on the surface facing the platen 34, in which a plurality of nozzles for ejecting ink are arranged in parallel. The nozzle row 12a extends in the Y direction, which intersects (orthogonal in this embodiment) with the direction of movement of the recording head 12 (X direction).

[0016] In the recording device 10, a recording operation is performed on the recording medium M, which has been transported to the recording start position by the transport mechanism, by ejecting ink while moving (scanning) the recording head 12 in the X direction based on the recording data. Next, the recording medium M is transported by the transport mechanism by a predetermined amount, and then the recording operation is performed again. In this way, the recording device 10 performs recording on the recording medium M based on the recording data by repeatedly and alternately executing the recording operation and the transport operation.

[0017] The recording unit 30 is equipped with a first sensor 36 and a second sensor 38 capable of detecting the edge of the recording medium M in the X direction. The first sensor 36 and the second sensor 38 are mounted on the carriage 32, thereby enabling them to reciprocate in the X direction via the carriage 32. The first sensor 36 is mounted on one side (right side) of the carriage 32 in the X direction. The second sensor 38 is mounted on the other side (left side) of the carriage 32 in the X direction. In the recording device 10, when not recording, the recording head 12 (carriage 32) is positioned in a standby position located on one side in the X direction. This standby position is located outside the recording area where the recording head 12 ejects ink onto the recording medium M for recording. As will be described in detail later, the first sensor 36 and the second sensor 38 are optical sensors. In this embodiment, the first sensor 36 and the second sensor 38 function as a detection unit capable of detecting the edge of the recording medium M in the X direction.

[0018] <First sensor and second sensor> Next, the configurations of the first sensor 36 and the second sensor 38 will be described. Figure 3 is a schematic diagram of the first sensor 36 and the second sensor 38, where (a) is the first sensor 36 and (b) is the second sensor.

[0019] The first sensor 36 includes a light-emitting unit 302 capable of irradiating light onto a platen 34 and a recording medium M supported by the platen 34, and a light-receiving unit 304 capable of receiving reflected light from the platen 34 and the recording medium M (see Figure 3(a)). In this embodiment, the light-emitting unit 302 is positioned on one side (rear side) in the Y direction relative to the light-receiving unit 304, but it is not limited to this, and for example, it may be positioned on the other side (front side) in the Y direction, or on one or the other side in the X direction.

[0020] The second sensor 38 includes a light-emitting unit 312 capable of irradiating light onto a platen 34 and a recording medium M supported by the platen 34, and a light-receiving member 314 capable of receiving reflected light from the platen 34 and the recording medium M (see Figure 3(b)). In this embodiment, the light-emitting unit 312 is positioned on the other side in the Y direction relative to the light-receiving member 314, but it is not limited to this, and for example, it may be positioned on one side in the Y direction, or on one or the other side in the X direction.

[0021] The light-receiving member 314 includes a light-receiving element section 320 in which multiple light-receiving elements are arranged in a matrix in the X and Y directions. That is, the light-receiving element section 320 has multiple rows of light-receiving elements arranged in a predetermined number in the Y direction, arranged along the X direction. In this specification, in each figure showing the light-receiving element section 320, including Figure 3, light-receiving elements located in the middle of the Y direction are omitted. The light-receiving member 314 forms three light-receiving sections in the light-receiving element section 320. Specifically, the first light-receiving section 322 is formed by one or more rows of light-receiving elements located on the other side of the X direction in the light-receiving element section 320. The second light-receiving section 324 is formed by one or more rows of light-receiving elements located on one side of the X direction in the light-receiving element section 320. In this embodiment, the first light-receiving section 322 and the second light-receiving section 324 overlap each other in the Y direction and are spaced apart in the X direction. Furthermore, a third light-receiving section 326 is formed by one or more rows of light-receiving elements located between the first light-receiving section 322 and the second light-receiving section 324 of the light-receiving element section 320, and which are not used in the first light-receiving section 322 and the second light-receiving section 324. The rows of light-receiving elements used in each light-receiving section may be fixed or they may be configured to be increased or decreased.

[0022] The outputs from each light-receiving unit in the light-receiving member 314 are input to the output switching amplifier 330. The output switching amplifier 330 is capable of switching the output mode. Specifically, the output switching amplifier 330 is configured to be switchable by the main controller 400 between a differential mode based on the output values ​​of the first light-receiving unit 322 and the second light-receiving unit 324, and a single mode based on the output value of the third light-receiving unit 326. In differential mode, the outputs from the first light-receiving unit 322 and the second light-receiving unit 324 are input to the differential amplifier 332 provided in the output switching amplifier 330. In single mode, the output from the third light-receiving unit 326 is input to the single amplifier 334 provided in the output switching amplifier 330.

[0023] <Configuration of the control system for the recording device> Next, the configuration of the control system of the recording device 10 will be described. Figure 4 is a block diagram showing the configuration of the control system of the recording device 10.

[0024] The recording device 10 is equipped with a main controller 400 that controls the overall operation of the recording device 10. The main controller 400 executes various processes based on programs and data stored in the FlashROM 402, RAM 404, etc. The FlashROM 402 is a non-volatile storage that stores programs, parameters, and correction data used in various processes. The RAM 404 is a volatile storage that temporarily holds programs and data.

[0025] The main controller 400 controls the ejection of ink from the recording head 12 via the head driver 406. The main controller 400 also controls the drive of various motors via the motor driver 408. The motors controlled by the motor driver 408 include a carriage (CR) motor 410 for moving the carriage 32 in the X direction and a line feed (LF) motor 412 for driving the drive roller (not shown) that transports the recording medium M. In addition to these motors, although not shown, motors that drive the maintenance unit (not shown) for maintaining and restoring the ink ejection performance from each nozzle in the recording head 12 are also controlled via the motor driver 408. The main controller 400 detects the drive amount of each motor using encoder sensors 414 corresponding to each motor and controls their drive. The encoder scale read by the encoder sensor 414 is a linear scale and a rotary scale, but in both cases, the drive amount is detected from the sensor count.

[0026] The main controller 400 is also connected to the first sensor 36 and the second sensor 38. In the first sensor 36, the main controller 400 controls the drive of the light-emitting unit 302. In the light-receiving unit 304 of the first sensor 36, the signal based on the amount of light received is amplified to a level suitable for the main controller 400, and the main controller 400 acquires an analog input level via the sensor input 416. In the second sensor 38, the main controller 400 controls the drive of the light-emitting unit 312. In the light-receiving member 314 of the second sensor 38, the signal based on the amount of light received is converted by the differential amplifier 332 (see Figure 3(b)) or single amplifier 334 of the output switching amplifier 330, and then amplified to a level suitable for the main controller 400. The main controller 400 acquires an analog input level of the amplified signal via the sensor input 416. To analogously adjust the received light signal level, the gain of the differential amplifier 332 is configured to be changeable from the main controller 400. Based on the signals obtained from the first sensor 36 and the second sensor 38, the main controller 400 acquires the position coordinates of the detection positions at each sensor in the position coordinate acquisition unit 418, and calculates the edge of the recording medium M in the X direction in the calculation unit 420.

[0027] <Detection operation by the first and second sensors> The recording medium M is generally white, while in this embodiment, the platen 34 has light-absorbing properties, meaning it is black. Therefore, almost all of the light emitted from the light-emitting part is reflected by the recording medium M, and almost all of it is absorbed by the platen 34. As a result, there is a difference in the amount of light received at the light-receiving part between the recording medium M and the platen 34. The first sensor 36 and the second sensor 38 detect the edge of the recording medium M based on this difference in the amount of light received at the light-receiving part between the recording medium M and the platen 34.

[0028] =Detection operation by the first sensor 36= First, an overview of the detection operation by the first sensor 36 will be explained. Figure 5 is a diagram illustrating the changes in the output of the first sensor 36 in three different states. Figure 6 is a diagram showing an example of the output waveform of the first sensor 36. Note that in Figure 5, for ease of understanding, the light-emitting unit 302 is positioned at a distance in the X direction from the light-receiving unit 304.

[0029] Figure 5 shows the case where the first sensor 36 moves above the recording medium M supported by the platen 34 from one side in the X direction to the other side (-X direction), and the state transitions in the order of Figure 5(a), Figure 5(b), and Figure 5(c). The light receiving unit 304 receives reflected light from within the spot diameter Sd of the light receiving unit 304, converts the received light into a voltage, and outputs a voltage corresponding to the amount of light. The light emitting unit 302 irradiates the entire area within the spot diameter Sd of the light receiving unit 304 with light.

[0030] When the recording medium M is located within the entire area of ​​the spot diameter Sd, the amount of light received by the light receiving unit 304 is maximized due to the reflected light from the recording medium M located within the spot diameter Sd, and the output voltage of the light receiving unit 304 reaches its maximum value (see Figure 5(a)).

[0031] As the first sensor 36 moves from the other side in the X direction to the other side, and the platen 34 is positioned within the region of the spot diameter Sd, the larger the proportion of the region occupied by the platen 34, the lower the amount of light reflected from the spot diameter Sd becomes. Therefore, as the first sensor 36 moves, the amount of light received by the light receiving unit 304 decreases, and the output voltage of the light receiving unit 304 gradually decreases (see Figure 5(b)).

[0032] Then, from the state shown in Figure 5(b), the first sensor 36 moves further from the other side in the X direction to the other side, until the recording medium M is no longer located within the entire area of ​​the spot diameter Sd, meaning only the platen 34 is located within that area. At this point, light reflected from within the spot diameter Sd is almost eliminated. As a result, the output voltage of the light receiving unit 304 becomes its minimum value (see Figure 5(c)).

[0033] The output waveform based on these changes in output voltage is shown in Figure 6. Near the edge of the recording medium M, where the proportion of the recording medium M within the spot diameter Sd changes, the output waveform changes, and the output voltage value decreases in accordance with the decrease in this proportion. Therefore, from this change in output waveform, the output voltage at the position corresponding to the edge position of the recording medium M is set as a threshold, and the position of the edge of the recording medium M is calculated from the coordinates when this threshold is passed. Such thresholds are determined experimentally, for example, depending on the type of recording medium M used.

[0034] =Detection operation by the second sensor 38= Next, an overview of the detection operation by the second sensor 38 will be described. The second sensor 38 is configured to allow selection between a differential mode using the first light receiving unit 322 and the second light receiving unit 324, and a single mode using the third light receiving unit 326. In other words, when the second sensor 38 is set to differential mode, it uses the first light receiving unit 322 and the second light receiving unit 324 to detect the edge of the recording medium M in the X direction, and when set to single mode, it uses the third light receiving unit 326 to detect the said edge.

[0035] • Detection operation in differential mode First, an overview of the detection operation using differential mode will be explained. Figure 7 illustrates the irradiation of light from the light-emitting unit 312 and the reception of light by the first light-receiving unit 322 and the second light-receiving unit 324 in the second sensor 38. Figure 8 shows the changes in output from the first light-receiving unit 322 and the second light-receiving unit 324 in three different states. Figure 9 shows the output waveforms of the first light-receiving unit 322 and the second light-receiving unit 324 and the output waveform of the differential amplifier 332 when the relative positional relationship between the recording medium M supported by the platen 34 and the second sensor is changed in the X direction. Note that in Figures 7, 8, and 9, the light-emitting unit 312 is positioned at a distance in the X direction from the light-receiving member 314 for ease of understanding.

[0036] In differential mode, the first light receiving unit 322 receives reflected light from the light receiving region La1 that it can receive, converts the received light into a voltage, and outputs a voltage corresponding to the amount of light. Also in differential mode, the second light receiving unit 324 receives reflected light from the light receiving region La2 that it can receive, converts the received light into a voltage, and outputs a voltage corresponding to the amount of light. The light receiving regions La1 and La2 do not overlap in the X direction, but their areas coincide. The term "coincident area" is not limited to strictly coincidence, but also includes cases where the difference between the areas of the two light receiving regions La1 and La2 is within a predetermined range.

[0037] In differential mode, the output voltages from the first light-receiving unit 322 and the second light-receiving unit 324 are input to the differential amplifier 332. The differential amplifier 332 amplifies the difference between the voltage value VA output from the first light-receiving unit 322 and the voltage value VB output from the second light-receiving unit 324, and outputs a differential signal Vout. The light-emitting unit 312 illuminates all areas within the light-receiving region La1 of the first light-receiving unit 322 and all areas within the light-receiving region La2 of the second light-receiving unit 324 with light.

[0038] The changes in the output waveforms of the first light-receiving unit 322 and the second light-receiving unit 324 in differential mode will be explained with reference to Figure 8, focusing on one of the light-receiving units. Figure 8 shows the case where the second sensor 38 moves above the recording medium M supported by the platen 34 from one side in the X direction to the other side (-X direction), and transitions from the state shown in Figure 8(a) to the state shown in Figure 8(b) and then to the state shown in Figure 8(c). When the recording medium M is located within the entire light-receiving region La, the amount of light received by the light-receiving unit is maximized by the reflected light from the recording medium M located within the light-receiving region La, and the output voltage of the light-receiving unit is maximized (see Figure 8(a)).

[0039] As the second sensor 38 moves from one side to the other in the X direction, and the platen 34 is positioned within the light-receiving region La, the larger the proportion of the region occupied by the platen 34, the less light is reflected from the light-receiving region La. Therefore, as the second sensor 38 moves, the amount of light received by the light-receiving section decreases, and the output voltage of the light-receiving section gradually decreases (see Figure 8(b)).

[0040] Then, from the state shown in Figure 8(b), the second sensor 38 moves further from the other side in the X direction to the other side, so that the recording medium M is no longer located within the entire light-receiving region La, meaning only the platen 34 is located within it. At this point, light reflected from within the light-receiving region La is almost eliminated. As a result, the output voltage of the light-receiving section becomes its minimum value (see Figure 8(c)).

[0041] In the second sensor 38, the output voltage changes in the first light-receiving unit 322 and the second light-receiving unit 324 as described above. Since the first light-receiving unit 322 and the second light-receiving unit 324 are located at different positions in the X direction, the position where the output voltage changes (where the output waveform slopes) is shifted in the X direction. The output voltages of the first light-receiving unit 322 and the second light-receiving unit 324 are input to the differential amplifier 332. The differential amplifier 332 outputs a differential signal Vout based on the difference between the output voltage of the first light-receiving unit 322 and the output voltage of the second light-receiving unit 324. Therefore, the output waveform showing the change in the differential signal Vout forms a waveform of a predetermined shape in the region where there is a difference between the output voltage of the first light-receiving unit 322 and the output voltage of the second light-receiving unit 324, that is, near the edge of the recording medium M. The output waveform of the differential amplifier 332 will be described below with reference to Figure 9.

[0042] Assume that the second sensor 38 is located at a first position where the recording medium M is positioned across the entire light-receiving area La1 of the first light-receiving unit 322 and the light-receiving area La2 of the second light-receiving unit 324. In this case, both the output voltage VA of the first light-receiving unit 322 and the output voltage VB of the second light-receiving unit 324 reach their maximum values ​​and are the same. Therefore, at the first position, the difference between the output voltage VA and the output voltage VB becomes 0V, and the differential signal Vout from the differential amplifier 332 becomes 0V. Note that in Figure 9, a gap is provided between the output waveforms of the output voltage VA and the output waveform of the output voltage VB where the output voltages are the same, for the sake of easier understanding.

[0043] When the second sensor 38 moves from the first position to the other side in the X direction, the second sensor 38 transitions to a second position in which the recording medium M is positioned over the entire light-receiving area La1 of the first light-receiving unit 322, while the platen 34 is positioned over a portion of the light-receiving area La2 of the second light-receiving unit 324. In this second position, a difference arises between the output voltage VA of the first light-receiving unit 322 and the output voltage VB of the second light-receiving unit 324. Specifically, the output voltage VA of the first light-receiving unit 322 becomes higher than the output voltage VB of the second light-receiving unit 324. More specifically, the output voltage VA of the first light-receiving unit 322 maintains its maximum value, while the output voltage VB of the second light-receiving unit 324 gradually decreases as it moves. Therefore, in the second position, the difference between the output voltage VA and the output voltage VB gradually increases with movement, causing the differential signal Vout to increase.

[0044] Furthermore, if the second sensor 38 moves further from the second position to the other side in the X direction, the second sensor 38 transitions to the third position. In the third position, the recording medium M is located over the entire light-receiving area La1 of the first light-receiving unit 322, while the platen 34 is located over the entire light-receiving area La2 of the second light-receiving unit 324. In this third position, the output voltage VA of the first light-receiving unit 322 maintains its maximum value, while the output voltage VB of the second light-receiving unit 324 reaches and maintains its minimum value. As a result, the difference between the output voltage VA and the output voltage VB becomes maximum, and consequently, the differential signal Vout takes its maximum value.

[0045] Subsequently, as the second sensor 38 moves further from the third position to the other side in the X direction, the second sensor 38 transitions to the fourth position. In the fourth position, the platen 34 is located in a part of the light-receiving area La1 of the first light-receiving unit 322, and the platen 34 is located in the entire light-receiving area La2 of the second light-receiving unit 324. In this fourth position, the output voltage VA of the first light-receiving unit 322 gradually decreases with movement, while the output voltage VB of the second light-receiving unit 324 maintains its minimum value. Therefore, in the fourth position, the difference between the output voltage VA and the output voltage VB gradually decreases with movement, and as a result, the differential signal Vout decreases.

[0046] Then, from the fourth position, as the second sensor 38 moves further from the other side in the X direction to the other side, the second sensor 38 transitions to the fifth position. In the fifth position, the platen 34 is positioned over the entire area of ​​both the light-receiving region La1 of the first light-receiving unit 322 and the light-receiving region La2 of the second light-receiving unit 324. In this fifth position, the output voltage VA of the first light-receiving unit 322 and the output voltage VB of the second light-receiving unit 324 both take their minimum values ​​and become the same value. Therefore, in the fifth position, the difference between the output voltage VA and the output voltage VB becomes 0V, and the differential signal Vout from the differential amplifier 332 becomes 0V.

[0047] In response to the change in the output Vout of the differential amplifier 332, the system detects a position P1 that exceeds a preset first threshold Th1 and a position P2 that falls below the first threshold Th1, and acquires the midpoint P0 as the edge position of the recording medium M. This first threshold Th1 is determined experimentally, for example, depending on the type of recording medium M used.

[0048] • Detection operation in single mode Next, an overview of the detection operation in single mode will be described. Figure 10 shows the output waveform corresponding to the change in the output voltage VC of the third light receiving unit 326 and the output waveform corresponding to the change in the output signal Vout of the single amplifier 334, when the relative positional relationship between the recording medium M supported by the platen 34 and the second sensor 38 is changed in the X direction. Note that the light-emitting unit 312 is omitted in Figure 10 for ease of understanding.

[0049] In single mode, the third light-receiving unit 326 receives reflected light within the light-receiving region La3 that it can receive, converts the received light into a voltage, and outputs a voltage corresponding to the amount of light. The output voltage from the third light-receiving unit 326 is input to the single amplifier 334, where it is amplified, inverted, and output. The light-emitting unit 312 illuminates all areas within the light-receiving region La3 of the third light-receiving unit 326 with light.

[0050] The changes in the output waveform at the third light receiving unit 326 and the output waveform at the single amplifier 334 in single mode will be explained with reference to Figure 10. Figure 10 shows the case where the second sensor 38 moves above the recording medium M supported by the platen 34, from one side in the X direction to the other side (-X direction).

[0051] Assume that the second sensor 38 is located at the sixth position where the recording medium M is positioned within the entire light-receiving area La3 of the third light-receiving unit 326. In this case, the output voltage VC of the third light-receiving unit 326 becomes the maximum value, and the output signal Vout based on this output voltage VC becomes the minimum value.

[0052] When the second sensor 38 moves from the sixth position to the other side in the X direction, the second sensor 38 transitions to the seventh position, where the platen 34 is positioned within a portion of the light-receiving area La3 of the third light-receiving unit 326. In this seventh position, the amount of light received by the third light-receiving unit 326 decreases in proportion to the proportion of the light-receiving area La3 occupied by the platen 34. Therefore, in the seventh position, the output voltage VC of the third light-receiving unit 326 gradually decreases as it moves. As a result, the output signal Vout gradually increases in accordance with the change in the output voltage VC.

[0053] Then, as the second sensor 38 moves further from the seventh position to the other side in the X direction, the second sensor 38 transitions to the eighth position, where the platen 34 is positioned over the entire light-receiving area La3 of the third light-receiving unit 326. At this eighth position, reflected light from the light-receiving area La3 is almost eliminated, and the amount of light received by the third light-receiving unit 326 is minimized. Therefore, at the eighth position, the output voltage VC of the third light-receiving unit 326 becomes its minimum value, and the output signal Vout based on this output voltage VC becomes its maximum value.

[0054] Then, based on the output voltage VC of the third light-receiving unit 326, the output signal Vout of the single amplifier 334 changes, and the position P3 that has passed a preset second threshold Th2 is detected. This position P3 is then acquired as the edge position of the recording medium M. This second threshold Th2 is determined experimentally, for example, depending on the type of recording medium M used.

[0055] <Recording process> In the above configuration, the recording device 10 performs a recording process to record data onto the recording medium M based on a recording job. Figure 11 is a flowchart detailing the contents of the recording process. Figure 12 shows the positions of the first sensor 36 and the second sensor 38 relative to the recording medium M at each timing during the recording process. The series of processes shown in the flowchart of Figure 11 are performed by the main controller 400 loading the program code stored in the FlashROM 402 into the RAM 404 and executing it. Alternatively, some or all of the functions of the steps in Figure 11 may be performed by hardware such as an ASIC or electrical circuit. In this specification, the symbol S in the description of each process in the flowchart means a step in that flowchart.

[0056] In the following description, the recording device 10 will be described as recording in both directions, specifically in the forward direction (+X direction) from one side of the X-direction to the other (-X direction) and the return direction (-X direction) from the other side of the X-direction to the one side (-X direction). The recording device 10 records an image based on the recorded data on the recording medium M by repeatedly performing a scan accompanied by recording by the recording head 12. In this embodiment, the main controller 400 functions as a recording control unit that controls the recording unit 30's bidirectional recording in both the forward and return directions.

[0057] When the recording process begins, first, in S1102, the main controller 400 sets the variable n, which indicates the number of scans accompanied by recording by the recording head 12, to "1". Next, in S1104, the main controller 400 performs the nth scan accompanied by recording. Specifically, when the variable n is 1, the recording head 12 in the standby position (see Figure 12(a)) moves in the forward direction and ejects ink onto the recording medium M to record (see Figure 12(b)). When the variable n is an even number, the recording head 12 in the stopping position on the other side of the X direction (see Figure 12(f)) moves in the return direction and ejects ink onto the recording medium M to record (see Figure 12(g)). Furthermore, when the variable n is an odd number other than "1", the recording head 12 in the stopping position on one side of the X direction (see Figure 12(k)) moves in the forward direction and ejects ink onto the recording medium M to record (see Figure 12(l)).

[0058] During scanning with recording, the recording start position in the X direction is set to the position set in S1110 if it is immediately after passing through S1108-S1110 described later, and to the position set in S1118 if it is immediately after passing through S1116-S1118 described later. Note that when the variable n is "1", that is, during the first scanning with recording, a pre-set position may be used as the recording start position in the X direction. Alternatively, the carriage 32 may be scanned before the first scanning with recording to detect the position of one end ER of the recording medium M using the first sensor 36 or the second sensor 38, and the recording start position in the X direction for the first scanning with recording may be set based on the detection result.

[0059] When the scan involving the nth recording begins, in S1106, the main controller 400 determines whether the variable n is odd or not. Here, in the recording device 10, during scans involving odd-numbered recordings, the recording head 12 moves in the forward direction from one side to the other in the X direction, and during scans involving even-numbered recordings, the recording head 12 moves in the reverse direction from the other side to the one side in the X direction.

[0060] Therefore, in scans involving odd-numbered recordings in the forward direction, the second sensor 38 can detect the other end EL of the recording medium M in the X direction before the first sensor 36 (see Figure 12(c)). Also, in scans involving odd-numbered recordings, detecting the end EL using the second sensor 38 rather than the first sensor 36 allows the recording head 12 to travel a shorter distance in the forward direction (see Figure 12(d)).

[0061] On the other hand, in scans involving even-numbered recordings that move in the reverse direction, the first sensor 36 can detect the edge ER of one side of the recording medium in the X direction before the second sensor 38 (see Figure 12(h)). Also, in scans involving even-numbered recordings, detecting the edge ER using the first sensor 36 rather than the second sensor 38 allows the recording head 12 to travel a shorter distance in the reverse direction (see Figure 12(i)).

[0062] In S1106, if it is determined that the variable n is odd, the process proceeds to S1108, where the main controller 400 determines whether the second sensor 38 has detected the other end EL of the recording medium M. The detection of the end position of the recording medium M by the second sensor 38 is performed based on the differential mode or single mode setting. In differential mode, as the device moves in the scanning direction, the coordinates of two points where the differential signal Vout of the differential amplifier 332 passes the first threshold Th1 are obtained, and the midpoint P0 between these two points is detected as the end position of the recording medium M. In single mode, as the device moves in the scanning direction, the point where the output signal Vout of the single amplifier 334 passes the second threshold Th2 is detected as the end position of the recording medium M. Thus, in this embodiment, the main controller 400 (position coordinate acquisition unit 418 and calculation unit 420) functions as an acquisition unit that detects the end of the recording medium M in the X direction and acquires the end position.

[0063] In S1108, if the second sensor 38 determines that the edge EL of the recording medium M has been detected (see Figure 12(c)), the process proceeds to S1110, where the main controller 400 sets the position of the detected edge EL as the recording start position in the X direction for the next scan involving recording. Thus, in this embodiment, the main controller 400 functions as a determination unit that determines the recording start position for the next scan involving recording.

[0064] When the nth recording scan is completed, the carriage 32 stops at a stopping position downstream in the direction of movement during that scan (see Figure 12(d)(i)). Subsequently, the recording device 10 transports a predetermined amount of recording medium M using the transport mechanism (see Figure 12(e)(j)) and waits until the next recording scan is executed.

[0065] Subsequently, in S1112, the main controller 400 determines whether or not recording based on the recording job has finished. If it is determined in S1112 that recording based on the recording job has finished, the recording process is terminated. If it is determined in S1112 that recording based on the recording job has not finished, the process proceeds to S1114, where the main controller 400 increments the variable n and returns to S1104.

[0066] Furthermore, if it is determined in S1106 that the variable n is even, the process proceeds to S1116, where the main controller 400 determines whether or not the first sensor 36 has detected one end ER of the recording medium M. The first sensor 36 detects the point where the output voltage of the light receiving unit 304 of the first sensor 36 passes a threshold as it moves in the scanning direction, and this point is determined to be the end position of the recording medium M. If it is determined in S1116 that the first sensor 36 has detected the end ER of the recording medium M (see Figure 12(h)), the process proceeds to S1118. In S1118, the main controller 400 sets the position of the detected end ER as the recording start position in the X direction for the next scan involving recording, and proceeds to S1112.

[0067] <Variation> In the above description, we have described a case in which the recording device 10 performs bidirectional recording, recording when it moves in the forward and return directions in the X direction. However, the technology of this disclosure is not limited to recording devices that perform bidirectional recording. The technology of this disclosure can also be applied to recording devices that perform unidirectional recording, recording when it moves in the forward or return direction in the X direction.

[0068] In this case, for example, when recording is performed while the recording head 12 is moving in the forward direction, the position of one end ER of the recording medium M corresponds to the recording start position. Therefore, when a scan with recording is completed and the recording medium moves to the start position for the next scan with recording, the processes of S1116 and S1118 are executed. Also, for example, when recording is performed while the recording head 12 is moving in the reverse direction, the position of the other end EL of the recording medium M corresponds to the recording start position. Therefore, when a scan with recording is completed and the recording medium moves to the start position for the next scan with recording, the processes of S1108 and S1110 are executed.

[0069] In the above description, the sensor for detecting the edge position of the recording medium M is determined based on the number of scans accompanied by recording by the recording head 12 during the recording process, but it is not limited to this. For example, the sensor for detecting the edge position may be determined based on the direction in which the recording head 12 scans. Specifically, when the recording head 12 moves in the forward direction, the second sensor 38 detects the edge EL of the recording medium M, and when the recording head 12 moves in the reverse direction, the first sensor 36 detects the edge ER of the recording medium M.

[0070] Although not specifically mentioned in the above description, the second sensor 38 is used to detect the other end EL of the recording medium M in the X direction, but is not limited to this. For example, it may be used to detect the one end ER of the recording medium M in the X direction, to detect the passage of the recording medium on the platen, or to detect the leading edge of the recording medium M in the transport direction. Similarly, the first sensor 36 is used to detect the one end ER of the recording medium M in the X direction, but is not limited to this. For example, it may be used for register adjustment to adjust the landing position of ejected ink droplets.

[0071] In the above description, the first sensor 36 is provided on one side of the carriage 32 in the X direction, and the second sensor 38 is provided on the other side of the carriage 32 in the X direction, but the invention is not limited to this. The first sensor 36 may be provided on the other side of the carriage 32 in the X direction, and the second sensor 38 may be provided on one side of the carriage 32 in the X direction. Alternatively, the first sensor 36 may be omitted, and the second sensor 38 may be provided on both one side and the other side of the carriage 32 in the X direction.

[0072] In the above description, the second sensor 38 is provided with a third light receiving unit 326, but it may also be configured without the third light receiving unit 326. Furthermore, the configuration of the output switching amplifier 330, the position coordinate acquisition unit 418 and the calculation unit 420 which acquire the edge position of the recording medium M based on the output values ​​from the first sensor 36 and the second sensor 38 may be provided in an external device connected to the recording device 10. Also, in the above description, the edge EL is detected using the second sensor in S1108 and the edge ER is detected using the first sensor 36 in S1116, but it is not limited to this. The detection of the edge EL in S1108 and the detection of the edge ER in S1116 may be performed using the differential mode of the second sensor 38.

[0073] <Effects and Effects> As described above, in the recording device 10 according to this embodiment, a first sensor 36 is provided on one side of the carriage 32 on which the recording head 12 is mounted in the direction of movement, and a second sensor 38 is provided on the other side in the same direction of movement. Then, during scanning accompanied by recording by the recording head 12, the edge position of the recording medium M is acquired by the first sensor 36 or the second sensor 38. Subsequently, based on the acquired edge position, the recording start position in the direction of movement during the next scanning accompanied by recording is determined.

[0074] This shortens the scanning range of the recording head 12 (carriage 32) during recording scanning, contributing to miniaturization of the recording device 10 and a reduction in the time required for recording processing. Furthermore, since the recording start position for the next recording scan is acquired during a scan that involves recording, it becomes less likely for margins to occur when performing borderless recording, and it becomes possible to record right up to the edges EL and ER in the scanning direction of the recording medium M. Consequently, it becomes possible to perform micro-margin recording, which creates a very small margin at the edges EL and ER and provides a visual effect equivalent to borderless recording. In this case, it becomes unnecessary to install, for example, an absorber on the platen 34, and the configuration around the platen 34 can be simplified.

[0075] (Second Embodiment) Next, a recording device according to the second embodiment will be described with reference to Figures 13 and 14. In the following description, detailed explanations of components that are the same as or equivalent to those in the recording device according to the first embodiment described above will be omitted, as the same reference numerals used in the first embodiment will be used.

[0076] As described above, in differential mode, the second sensor 38 is configured to receive reflected light from the light-emitting unit 312 at the first light-receiving unit 322 and the second light-receiving unit 324, and output a voltage corresponding to the amount of light received. For this reason, minute pulses may be formed in the output waveform of the differential amplifier 332 due to fluctuations or noise in the sensor signal. If the magnitude of such pulses exceeds the first threshold Th1, four or more points will be formed where the output voltage passes the first threshold Th1, which may make it impossible to accurately detect the edge of the recording medium M in the X direction.

[0077] In the second embodiment, even if pulses formed by fluctuations or noise in the sensor signal are generated with a magnitude exceeding the first threshold Th1, the edge position of the recording medium in the X direction can be accurately obtained. Specifically, from a pair of coordinates that pass the first threshold Th1 during the rising and falling edges of the output waveform, the coordinates in the pair whose distance between the two coordinates is closest to the theoretical value are taken as true values, and the edge position of the recording medium in the X direction is obtained using these true values.

[0078] <Overview of obtaining the edge position of the recording medium> First, an overview of how the edge position of the recording medium in the X direction is obtained in the recording device 10 according to this embodiment will be described. Figure 13 is a diagram illustrating the overview of how the edge position of the recording medium is obtained in the recording device 10 according to this embodiment. In Figure 13, for ease of understanding, the light-emitting unit 312 is positioned at a distance in the X direction from the light-receiving member 314. Also, in Figure 13, for ease of understanding, a gap is provided between the output waveform of the output voltage VA and the output waveform of the output voltage VB where the output voltage is the same.

[0079] Assume that when the second sensor 38 moves from the recording medium M, through one end ER of the recording medium M, to the platen 34, the output signal VB decreases due to the influence of noise N before the second light receiving unit 324 passes the end ER. In this case, in the output waveform based on the output signal Vout of the differential amplifier 332, a waveform Wa2 due to the influence of noise N is formed near the waveform Wa1 formed near the end ER.

[0080] The position coordinate acquisition unit 418 acquires the first coordinate when the waveform Wa1 and waveform Wa2 exceed the first threshold Th1, and the second coordinate when the waveform Wa2 falls below the first threshold Th1, respectively. Specifically, it acquires the first coordinate Pa and the second coordinate Pb for waveform Wa1, and the first coordinate Pc and the second coordinate Pd for waveform Wa2. Then, the position coordinate acquisition unit 418 acquires the distance L between the first and second coordinates, compares it with a theoretical value T, and sets the first and second coordinates that have the distance L closest to the theoretical value T as the true values. In this embodiment, the theoretical value T is the distance between the center position of the first light receiving unit 322 and the center position of the second light receiving unit 324 in the X direction. Then, the calculation unit 420 acquires the midpoint P0 of the true values ​​of the first and second coordinates as the edge ER of the recording medium M.

[0081] In this embodiment, the distance L1 between the first coordinate Pa and the second coordinate Pb of waveform Wa1 is closer to the theoretical value T than the distance L2 between the first coordinate Pc and the second coordinate Pd of waveform Wa2, so the first coordinate Pa and the second coordinate Pb are considered true values. Then, the end point ER is obtained based on the first coordinate Pa and the second coordinate Pb which are considered true values. Note that the method for obtaining the end point position of the recording medium M is not limited to this. For example, the first or second coordinate which is considered a true value may be determined as the end point position. Alternatively, the end point position may be determined by adding or subtracting an offset distance based on a theoretical value from the first or second coordinate which is considered a true value.

[0082] <Retrieval process> Next, we will describe the acquisition process for acquiring the edge of the recording medium M from the differential signal Vout of the differential amplifier 332 in differential mode. Note that the acquisition process described below starts after the scan accompanied by the nth recording in S1104 has begun in the recording process described above, and is executed, for example, in S1108. Figure 14 is a flowchart detailing the process of acquiring the edge of the recording medium M from the differential signal Vout. The series of processes shown in the flowchart of Figure 14 are performed by the main controller 400 loading the program code stored in the FlashROM 402 into the RAM 404 and executing it. Alternatively, some or all of the functions of the steps in Figure 14 may be performed by hardware such as an ASIC or electrical circuit.

[0083] When the acquisition process begins, in S1402, the main controller 400 first determines whether the acquired differential signal Vout from the differential amplifier 332 has passed the first threshold Th1. Specifically, when scanning accompanied by recording by the recording head 12 begins, the main controller 400 starts monitoring the differential signal Vout from the differential amplifier 332. Therefore, in S1402, if the differential signal Vout is rising, it is determined whether the differential signal Vout has exceeded the first threshold Th1, and if the differential signal Vout is falling, it is determined whether the differential signal Vout has fallen below the first threshold Th1. In other words, in S1402, if it is determined that the differential signal Vout has exceeded or fallen below the first threshold Th1, it is determined that the differential signal Vout has passed the first threshold Th1. Also, if it is determined that the differential signal Vout has not exceeded or fallen below the first threshold Th1, it is determined that the differential signal Vout has not passed the first threshold Th1. In S1402, if it is determined that the differential signal Vout has passed the first threshold Th1, the coordinate values ​​at the time of this determination, that is, when the differential signal Vout reached the first threshold Th1, are obtained.

[0084] In S1402, if it is determined that the differential signal Vout has not passed the first threshold Th1, the process proceeds to S1410, which will be described later. Also, in S1402, if it is determined that the differential signal Vout has passed the threshold Th1, the process proceeds to S1404, where the main controller 400 determines whether the most recently acquired coordinate is the first coordinate. In S1404, if it is determined that the most recently acquired coordinate is not the first coordinate, the process proceeds to S1406, where the main controller holds the coordinate acquired in S1402 as the first coordinate and proceeds to S1410. Also, in S1404, if it is determined that the most recently acquired coordinate is the first coordinate, the process proceeds to S1408, where the main controller 400 holds the coordinate acquired in S1402 as the second coordinate and proceeds to S1410. In S1408, the held second coordinate is associated with the most recently acquired first coordinate.

[0085] In S1410, the main controller 400 determines whether the carriage 32 has moved to the stopping position. The stopping position is pre-stored in the memory area of ​​the recording device 10. If it is determined in S1410 that the carriage has not moved to the stopping position, the process returns to S1402. If it is determined in S1410 that the carriage has moved to the stopping position, the process proceeds to S1412, where the main controller 400 obtains the true coordinate values.

[0086] In S1412, the distance between the two associated coordinates, the first and second coordinates, is obtained, and the first and second coordinates whose obtained distance most closely approximates the theoretical value T are obtained as the true values ​​of the coordinates. The theoretical value T is pre-stored in the memory area. If there is only one pair of associated first and second coordinates, these coordinates will be obtained as the true values. Subsequently, in S1414, the main controller 400 obtains the edge of the recording medium M from the first and second coordinates that have been set as true values, and terminates this acquisition process. Specifically, in S1414, the midpoint P0 of the first and second coordinates that have been set as true values ​​is obtained as the edge of the recording medium M in the X direction.

[0087] <Variation> In the explanation above, all acquired first and second coordinates are stored, and then the true values ​​of the coordinates are obtained. However, this is not the only way. For example, after acquiring the second coordinate, the distance between the two coordinates (the first and second coordinates) is obtained. If the difference between this distance and the theoretical value T is greater than a predetermined value, the first and second coordinates are judged to be abnormal values ​​and are not stored in the memory. In other words, in this case, the midpoint between the two points where the difference is less than or equal to the predetermined value is acquired as the edge of the recording medium M and stored in the memory. The predetermined value is, for example, 20% of the theoretical value T. This reduces the amount of recording space used when executing the acquisition process.

[0088] <Effects and Effects> As described above, in this embodiment, the distance between the two acquired first and second coordinates is compared with a theoretical value based on the distance between the first light-receiving unit 322 and the second light-receiving unit 324. The two coordinates whose distance approximates the theoretical value are then set as the true values ​​of the first and second coordinates, and the edge of the recording medium M is acquired using these true values. As a result, even if fluctuations or noise occur in the output signal from the light-receiving unit, the recording device 10 can eliminate waveforms caused by these in the output waveform of the differential signal Vout, and accurately detect the edge of the recording medium M.

[0089] (Third embodiment) Next, a recording device according to the third embodiment will be described with reference to Figures 15 to 19. In the following description, detailed explanations of components that are the same as or equivalent to those in the recording device according to the first embodiment described above will be omitted, as the same reference numerals used in the first embodiment will be used.

[0090] The first sensor 36 is less expensive than the second sensor 38 due to its simpler configuration, but because it performs detection based on the output voltage from a single light-receiving unit, it is susceptible to influences such as the carriage's movement speed. Furthermore, in the recording device 10, the movement speed of the carriage 32 on which the first sensor 36 is installed varies depending on the recording mode and image pattern. As a result, there is a risk of variability in the detection accuracy of the first sensor 36.

[0091] The third embodiment differs from the first embodiment described above in that it suppresses changes in the movement speed of the first sensor 36 when detecting the edge of the recording medium M, thereby suppressing variations in the detection accuracy of the first sensor 36. In the following description, "movement speed of the first sensor 36 when detecting (passing over) the edge of the recording medium M" means the speed at which the first sensor 36, which is moved via the carriage 32, detects (passes over) the edge of the recording medium M. In other words, it means the movement speed of the carriage 32 when the first sensor 36 detects (passes over) the edge of the recording medium M.

[0092] <Micromargin Recording> Next, we will explain the size of the recorded image and the recording start position in the X direction when performing micro-margin recording, which can obtain a visual effect similar to borderless recording. Figures 15(a) and 15(b) show the size of the recorded image relative to the recording medium M and the recording start position in the X direction when performing micro-margin recording. Figure 15(a) shows the recording start position when the carriage 32 moves (scans) in the forward direction, and Figure 15(b) shows the recording start position when the carriage 32 moves in the reverse direction. Note that the second sensor 38 is omitted from Figures 15(a) and 15(b) for ease of understanding.

[0093] The recording medium M may experience displacement at its edge position in the X direction due to factors such as skew during transport or expansion from its nominal value due to humidity. Therefore, in micro-margin recording, which records images right up to the edge of the recording medium M, the recorded image Ig is generated by enlarging it by a predetermined amount Ti beyond the size of the recording medium M in the X direction. Then, the timing of ink ejection from each nozzle row is adjusted to record from the very edges EL and ER of the recording medium M. Whether or not to perform micro-margin recording is at the user's discretion. For the edges EL and ER, for example, the most recently acquired position information is used.

[0094] <Movement speed of the first sensor> Next, we will explain the change in the movement speed of the first sensor 36 during scanning with recording. Figure 16 illustrates the change in the movement speed of the first sensor 36 during scanning with recording due to differences in the nozzle rows that eject ink. Figure 16(a) shows the change in the movement speed of the first sensor 36 when ink is ejected from the nozzle row located furthest downstream in the direction of movement of the carriage 32. Figure 16(b) shows the change in the movement speed of the first sensor 36 when ink is ejected from a nozzle row located upstream in the direction of movement from the nozzle row that ejects ink in Figure 16(a).

[0095] When recording a recording image Ig on the recording medium M, the movement speed of the carriage 32 reaches a predetermined speed Sp before recording the recording image Ig, maintains the predetermined speed Sp during the recording of the recording image Ig, and then decelerates from the predetermined speed Sp after the recording of the recording image Ig.

[0096] Specifically, during scanning with recording in the dual direction (-X direction), movement begins from the stopping position on the other side of the X direction, and the movement speed of the carriage 32 gradually increases, reaching a predetermined speed Sp at the time when recording of the recorded image Ig begins. Thereafter, the movement speed of the carriage 32 is maintained at the predetermined speed Sp during the recording of the recorded image Ig. Then, at the time when recording of the recorded image Ig is completed, the movement speed of the carriage 32 decreases, and this movement speed gradually decreases until the carriage 32 stops at the stopping position on the one side of the X direction.

[0097] Since the first sensor 36 is mounted on the carriage 32, it moves at the same speed as the carriage 32. On the carriage 32, the first sensor 36 is located downstream in multiple directions from each nozzle row of the recording head 12. However, if the first sensor 36 is located upstream in the direction of movement from the edge ER of the recording medium M in the X direction at the time when recording to the recorded image Ig is completed, the first sensor 36 will decelerate before it can detect the edge ER (see Figure 16(a)).

[0098] Furthermore, the closer the nozzle row that ejects ink when recording the recorded image Ig is to the first sensor 36 in the X direction, the earlier the first sensor 36 will begin to decelerate. For example, when recording the recorded image Ig with the nozzle row 1602 located at the furthest downstream in the return direction in the recording head 12, the first sensor 36 begins to decelerate from coordinate PA (see Figure 16(a)). In contrast, when recording the recorded image Ig with the nozzle row 1604 located upstream of the nozzle row 1602 in the return direction in the recording head 12, the first sensor 36 begins to decelerate from coordinate PB, located downstream of coordinate PA in the return direction (see Figure 16(b)). Therefore, the movement speed Sp1 of the first sensor 36 when passing through the end ER after decelerating from coordinate PA is slower than the movement speed Sp2 of the first sensor 36 when passing through the end ER after decelerating from coordinate PB. Thus, it can be seen that the movement speed of the first sensor 36 when passing over the edge of the recording medium M differs depending on the position in the X direction of the nozzle row that records the edge position of the recording medium M.

[0099] As described above, the detection of the edge position of the recording medium M by the first sensor 36 is based on a value corresponding to the amount of light received by the light receiving unit 304 when the carriage 32 is moving. Therefore, if the movement speed of the first sensor 36 changes before it passes the edge ER, the coordinate at which the threshold (see Figure 6) is reached will change compared to when the movement speed does not change. As a result, the detected edge position will deviate from the edge position when the movement speed does not change.

[0100] <Change of stopping position> Therefore, in this embodiment, the stopping position of the carriage 32 is changed during scanning accompanied by recording to detect the edge of the recording medium M, so that the movement speed of the first sensor 36 when passing the edge of the recording medium M does not decrease from the movement speed when recording the recorded image Ig. Specifically, the stopping position of the carriage 32 during such scanning is shifted to the downstream side in the direction of movement during the scanning. The outline of the change in the stopping position will be described below with reference to Figure 17. Figures 17(a) and 17(b) are diagrams illustrating the outline of the change in the stopping position of the carriage 32.

[0101] Ink is ejected from the nozzle row 1702 of the recording head 12 onto the recording medium M to record a recorded image Ig. In this case, the stopping position of the carriage 32 is changed from the set stopping position SP (see Figure 17(a)) to the stopping position PP (see Figure 17(b)) downstream in the direction of movement of the carriage 32.

[0102] Specifically, the predetermined position PP corresponds to position P, which is the end ER of the recording medium M. ER Therefore, the position is set downstream of the carriage 32 in the direction of movement, separated by the deceleration distance Sdd of the carriage 32. The deceleration distance Sdd of the carriage 32 is the distance from when the carriage 32 starts to decelerate until it stops, or a distance that is a certain amount longer than that distance. As a result, the movement speed of the first sensor 36 when passing the end ER of the recording medium M will not decrease from the predetermined speed Sp when recording the recorded image Ig.

[0103] Note that for the designated position PP, at least position P ER Therefore, the position should be one that is separated by a deceleration distance Sdd on the downstream side in the direction of movement of the carriage 32. Thus, the predetermined position PP is, for example, position P ER Alternatively, the position may be set at a distance Sdd away from the downstream position Px (see Figure 17(b)) in the direction of movement, on the downstream side of the carriage 32. The deceleration distance Sdd can be determined experimentally, for example, depending on the movement speed of the carriage 32.

[0104] <Change Processing> Next, the process for changing the stopping position of the carriage 32 will be described. Figure 18 is a flowchart detailing the process for changing the stopping position of the carriage 32. The series of processes shown in the flowchart of Figure 18 are performed by the main controller 400 loading the program code stored in the Flash ROM 402 into the RAM 404 and executing it. Alternatively, some or all of the functions of the steps in Figure 18 may be performed by hardware such as an ASIC or electrical circuit.

[0105] Regarding the modification process shown in Figure 18, when micro-margin recording is performed in bidirectional recording, it is executed immediately before the S1104 process of the recording process (see Figure 11). In other words, the modification process is executed immediately before each scan that involves recording. Note that if the recording to be performed is not micro-margin recording, the modification process is not executed.

[0106] When the modification process is initiated, first, in S1802, the main controller 400 determines whether the variable n, which indicates the number of scans with recordings performed, is odd or not. In this embodiment, a first sensor 36 is provided on one side of the carriage 32, and a second sensor 38 is provided on the other side of the carriage 32. The second sensor 38 uses a differential signal based on the output signals from the first light receiving unit 322 and the second light receiving unit 324, so that the edge EL of the recording medium M can be accurately acquired regardless of the carriage's movement speed. For this reason, when scanning with recordings in the forward direction to detect the edge EL of the recording medium M using the second sensor 38, it is not necessary to change the stopping position of the carriage 32.

[0107] Therefore, in S1802, if it is determined that the variable n is odd, the second sensor 38 is used to detect the end EL of the recording medium M, and it is determined that this is a scan involving recording in the forward direction, and this modification process is terminated. Also, in S1802, if it is determined that the variable n is even, that is, that the variable n is not odd, the first sensor 36 is used to detect the end ER of the recording medium M, and it is determined that this is a scan involving recording in the reverse direction, and the process proceeds to S1804. In S1804, the main controller 400 acquires the position (coordinates) of the end ER. The position of the end ER to be acquired is the position information (coordinate information) acquired during the most recent scan involving recording in the reverse direction.

[0108] Note that if the variable is "2", the most recent scan involving recording in the reverse direction has not been performed. For this reason, for example, before actually performing recording based on the recording job, the carriage 32 is scanned in the reverse direction, and the positions of the end ER of the recording medium M are obtained during this scan. Therefore, in S1804, if the variable n is "2", the position information of the end ER obtained by the scan performed before recording is obtained.

[0109] Subsequently, in S1806, the main controller 400 changes the stopping position of the carriage 32 for the nth scan with recording, based on the position of the end ER acquired in S1804 and the deceleration distance Sdd that is stored in advance, and then terminates this modification process. Specifically, in S1806, the stopping position of the carriage 32 for the nth scan with recording is determined to be a position that is separated from the position of the end ER acquired in S1804 by the deceleration distance Sdd in the return direction. In other words, in S1806, the coordinate information for the stopping position of the carriage 32 is obtained by adding the deceleration distance Sdd to the coordinate information of the end ER in the X direction.

[0110] The movement speed of the carriage 32 when recording the image varies depending on the recording mode, etc. Therefore, the recording device 10 stores a corresponding deceleration distance Sdd in its memory area for each movement speed of the carriage 32 in the recording mode. Accordingly, the deceleration distance Sdd used in S1806 is determined based on the recording mode, etc.

[0111] <Variation> As described above, the second sensor 38 is configured to detect the edge of the recording medium M using only the third light-receiving unit 326. In other words, the second sensor 38 can be operated in a detection mode (single mode) that uses the same detection mechanism as the first sensor 36. Therefore, in this case, it is necessary to change the stopping position of the carriage 32 even when scanning that involves recording in the forward direction. The following describes the modification process when the second sensor 38 is operated in single mode.

[0112] Figure 19 is a flowchart detailing the process of changing the operation of the second sensor 38 to function in single mode. The series of processes shown in the flowchart of Figure 19 are performed by the main controller 400 loading the program code stored in the Flash ROM 402 into the RAM 404 and executing it. Alternatively, some or all of the functions of the steps in Figure 19 may be performed by hardware such as an ASIC or electrical circuit.

[0113] When the modification process shown in Figure 19 begins, first, in S1902, the main controller 400 determines whether the variable n, which indicates the number of scans with recordings performed, is odd or not. If it is determined in S1902 that the variable n is odd, the process proceeds to S1904, where the main controller 400 obtains the position (coordinates) of the end EL. The position of the end EL to be obtained is the position information (coordinate information) obtained during the most recent scan with recordings in the forward direction.

[0114] Note that if the variable n is "1", the most recent forward scan with recording has not been performed. For this reason, for example, before actually performing recording based on a recording job, the carriage 32 is scanned in both the forward and return directions, and the positions of the ends EL and ER of the recording medium M are obtained during these scans. Therefore, if the variable n is "1", the position information of the end EL obtained by the scan performed before recording is acquired.

[0115] Subsequently, in S1906, the main controller 400 changes the stopping position of the carriage 32 for the nth scan with recording, based on the position of the end EL acquired in S1904 and the deceleration distance Sdd that has been stored in advance, and then terminates this modification process. Specifically, in S1906, the stopping position of the carriage for the nth scan with recording is determined to be a position separated by the deceleration distance Sdd downstream in the forward direction from the position of the end EL acquired in S1904. In other words, in S1906, the coordinate information for the stopping position of the carriage 32 is obtained by adding the deceleration distance Sdd to the coordinate information of the end EL in the X direction.

[0116] The movement speed of the carriage 32 when recording the image varies depending on the recording mode, etc. Therefore, the recording device 10 stores a corresponding deceleration distance Sdd in its memory area for each movement speed of the carriage 32 in the recording mode. Accordingly, the deceleration distance Sdd used in S1906 and S1910 (described later) is determined based on the recording mode, etc.

[0117] Furthermore, if it is determined in S1902 that the variable n is not odd, i.e., even, then the process proceeds to S1908, and the main controller 400 obtains the position (coordinates) of the end ER. The position of the end ER to be obtained is the position information (coordinate information) obtained during the most recent scan accompanied by recording in the reverse direction. Note that if the variable n is "2", the most recent scan accompanied by recording in the reverse direction has not been performed. Therefore, if the variable n is "2", the position information of the end EL obtained by the scan performed before recording will be obtained.

[0118] Subsequently, in S1910, the main controller 400 changes the stopping position of the carriage 32 for the scan with the nth record, based on the position of the end ER acquired in S1908 and the deceleration distance Sdd that has been stored in advance, and then terminates this modification process. Specifically, in S1910, the stopping position of the carriage 32 for the scan with the nth record is determined to be a position separated by the deceleration distance Sdd downstream in the return direction from the position of the end ER acquired in S1908. In other words, in S1910, the coordinate information for the stopping position of the carriage 32 is obtained by adding the deceleration distance Sdd to the coordinate information of the end ER in the X direction.

[0119] <Variation> In the above description, the stopping position of the carriage 32 is changed when the end ER is detected by the first sensor 36 during a bidirectional scan accompanied by recording, but it is not limited to this. For example, the stopping position of the carriage 32 may be changed when it is determined that it is necessary to change it based on the size of the recorded image Ig in the X direction, the position of the end of the recorded image Ig relative to the end ER, the position of the nozzle row that ejects ink in the X direction, etc.

[0120] In the above explanation, the change in the stopping position of the carriage 32 is not limited to being performed when the end ER is detected by the first sensor 36. For example, it may be performed when the end EL of the recording medium M is detected in single mode by the second sensor 38.

[0121] <Effects and Effects> As described above, in this embodiment, the stopping position of the carriage 32 is changed during scanning accompanied by recording, in which the first sensor 36, whose detection accuracy varies depending on the change in moving speed when passing the edge of the recording medium M, is detected. Specifically, the stopping position of the carriage 32 is set to a position downstream in the scanning direction, separated from the position of the edge by a deceleration distance Sdd that takes into account the deceleration of the carriage 32 from the stopping position. As a result, in the recording device 10, the moving speed of the first sensor 36 when passing the edge does not decrease from the speed at which the recorded image is recorded, and variations in the detection accuracy of the first sensor 36 are less likely to occur.

[0122] (Fourth Embodiment) Next, a recording device according to the fourth embodiment will be described with reference to Figures 20 to 21. In the following description, detailed explanations of components that are the same as or equivalent to those in the recording device according to the first embodiment described above will be omitted, as the same reference numerals used in the first embodiment will be used.

[0123] The fourth embodiment differs from the third embodiment described above in that it corrects the detection result of the first sensor 36 in order to suppress variations in the detection accuracy of the first sensor 36 caused by the movement speed when passing over the edge of the recording medium M.

[0124] As described above, the recording device 10 records a recorded image Ig based on the recorded data by repeatedly performing the scanning associated with recording multiple times. Therefore, if the conditions remain constant, even if the movement speed of the first sensor 36 when passing the edge of the recording medium M is slower than the movement speed when recording the recorded image Ig, no change will occur in the scanning unit associated with recording. In other words, the speed of the first sensor 36 when passing the edge of the recording medium M will be the same value between scanning operations associated with recording. Examples of conditions include the fact that the nozzle row that ejects ink is fixed (see 20(a)) and the length of the recorded image Ig in the X direction is constant (see Figure 20(b)).

[0125] Therefore, in this embodiment, the edge position obtained based on the detection result of the first sensor 36 is corrected based on the speed difference between the speed at which the recorded image Ig moves during recording and the speed at which it moves when passing the edge of the recording medium M. The correction method will be described in detail below.

[0126] The scanning speed of the carriage 32 (the predetermined speed Sp described above) is determined according to recording conditions such as the recording mode. Once the scanning speed of the carriage 32 is determined, the acceleration region section AC, the constant velocity region section CV, and the deceleration region section DE (see Figure 20(a)) are determined. Then, based on the recording conditions such as the size of the recording medium M, the length of the recorded image Ig in the X direction, and the type of ink, as well as the deceleration region section DE described above, the moving speed of the first sensor 36 as it passes the edge of the recording medium M can be obtained.

[0127] Furthermore, the recording device 10 stores data in the FlashROM 402 showing the relationship between the difference between the moving speed of the first sensor 36 when passing the edge of the recording medium M and the reference speed, and the error in the position of the acquired edge. In the recording device 10, the speed at which the carriage 32 moves during recording is fixed, and this data covers the range of this moving speed. The reference speed can be any speed that the carriage 32 can move.

[0128] Specifically, the retained data is based on the movement speed in the constant velocity region section CV, and the data represents the correction amount used to correct the acquired end position for the difference between said movement speed and the movement speed of the first sensor 36 when passing the end of the recording medium M.

[0129] Figure 21 shows an example of data illustrating the relationship between the difference in travel speed and the correction amount. In Figure 21, the range of travel speeds (scanning speeds) that the carriage 32 can take during recording is from 10 IPS (inch / sec) to 40 IPS, with a reference speed of 25 IPS.

[0130] If the movement speed of the first sensor 36, acquired based on various recording conditions, is 35 IPS, the difference from the reference speed is "+10 (=35-25) IPS", and from the data in Figure 21, the corresponding correction amount is "+100 μm". Therefore, in this case, 100 μm is added to the position of the edge of the recording medium M, acquired based on the detection result of the first sensor 36. Also, if the movement speed of the first sensor 36, acquired based on various recording conditions, is 15 IPS, the difference from the reference speed is "-10 (15-25) IPS", and from the data in Figure 21, the corresponding correction amount is "-50 μm". Therefore, in this case, 50 μm is subtracted from the position of the edge of the recording medium, acquired based on the detection result of the first sensor 36.

[0131] <Variation> Although not specifically mentioned in the above description, the recording device 10 may be configured to selectively implement the technology according to the third embodiment and the technology according to the fourth embodiment, for example, depending on various recording conditions. Specifically, if the movement speed of the first sensor 36 when passing the edge of the recording medium is lower than a predetermined speed, the correction error will be large. For this reason, the stopping position of the carriage 32 is changed according to the technology of the third embodiment. On the other hand, if the movement speed is equal to or greater than the predetermined speed, the position of the edge of the recording medium M obtained based on the detection result of the first sensor 36 is corrected according to the technology of the fourth embodiment. The movement speed of the first sensor 36 when passing the edge of the recording medium M will be obtained based on the recording conditions.

[0132] Therefore, in this case, when a recording job is input, first, based on the recording conditions, it is determined whether the condition for the movement speed of the first sensor 36 when passing the edge of the recording medium M to be constant is met during the recording performed in the recording job. If it is determined that the condition for the movement speed to be constant is met, the movement speed of the first sensor 36 when passing the edge of the recording medium M is obtained from the recording conditions, and it is determined whether the obtained movement speed is greater than or equal to a predetermined speed. Subsequently, if it is determined that the movement speed is greater than or equal to the predetermined speed, the position of the edge of the recording medium M, which is obtained each time a scan accompanied by recording is performed, is corrected based on the stored data. If it is determined that the movement speed is less than the predetermined speed, the stopping position of the carriage 32 is changed each time a scan accompanied by recording is performed.

[0133] In the above explanation, the correction of the detection position is not limited to being performed when the first sensor 36 detects the end ER. For example, it may be performed when the second sensor 38 detects the end EL of the recording medium M in single mode.

[0134] (Fifth embodiment) Next, a recording device according to the fifth embodiment will be described with reference to Figures 22 to 25. In the following description, detailed explanations of components that are the same as or equivalent to those in the recording device according to the first embodiment described above will be omitted, as the same reference numerals used in the first embodiment will be used.

[0135] As described above, the recording device 10 detects the edge position of the recording medium M based on the change in the differential signal corresponding to the output from the second sensor 38, which is an optical sensor. However, the output voltage from the second sensor 38 and the differential signal output from the differential amplifier 332 may produce abnormal or unwanted outputs due to various factors. In this embodiment, even if such an abnormality occurs in the output, a position approximating the actual edge position of the recording medium M can be obtained as the edge position of the recording medium M.

[0136] <First form> As described above, since the second sensor 38 is an optical sensor, if ink stains, paper dust, reflective materials, etc. are attached to the recording medium M and platen 34, pulses caused by these attached materials are formed in the waveform showing the change in the differential signal Vout.

[0137] For example, dirt such as dust or ink may adhere to the recording medium M or the platen 34 near the edge of the recording medium M supported on the platen 34. In this case, in the output waveform showing the change in the differential signal Vout, a pulse caused by this dirt is formed separately from the pulse corresponding to the edge of the recording medium M (see Figure 22(a)). Figure 22(a) is a diagram showing the output waveform showing the change in the differential signal Vout when dirt such as dust or ink adheres to the recording medium M or the platen 34 near the edge of the recording medium M supported on the platen 34. Note that in Figures 22, 24, and 25, the shape of the output waveform (pulse waveform) showing the change in the differential signal Vout is simplified for ease of understanding.

[0138] In this case, for example, if the pulse width caused by contamination is approximately the same as the pulse width corresponding to the edge of the recording medium M, even if the technique according to the second embodiment described above is used, there is a risk that the edge of the recording medium M in the X direction may not be accurately detected. Note that pulse width refers to the distance between two points in a single pulse where the differential signal Vout passes through the first threshold Th1.

[0139] =Overview of obtaining the edge position of the recording medium= Therefore, in the first embodiment of the fifth embodiment, even if pulses formed by such dirt are generated with a width similar to that of pulses corresponding to the edge of the recording medium M, the edge position of the recording medium in the X direction can be accurately obtained.

[0140] Specifically, in this embodiment, a detection range is provided, and pulses outside this detection range are excluded from the pulses corresponding to the edge of the recording medium M (see Figure 22(b)). Figure 22(b) shows the pulses to be excluded when a detection range is provided. The detection range is a range in the width direction (X direction) of the recording medium M, and is set based on the reference position when transporting the recording medium (transport position of the recording medium), the size of the recording medium used, etc. Alternatively, the position of the recording medium M being transported by the transport unit may be read in advance by the first sensor 36 or the second sensor 38, and the detection range may be determined based on the information read. The specific coordinate values ​​are determined, for example, by setting the abutment position of the carriage 32 as the origin position, and determining the coordinate values ​​on one side of the X direction in the detection range and the coordinate values ​​on the other side.

[0141] For example, if the reference position when transporting the recording medium M is one end in the X direction of the transport path, then a first position corresponding to that end and a second position spaced apart from that end by the size of the recording medium M being used are acquired. Then, a predetermined range centered on the first position is set as the detection range corresponding to one end, and a predetermined range centered on the second position is set as the detection position corresponding to the other end.

[0142] Furthermore, if the reference position for transporting the recording medium M is at the center of the transport path in the X direction, the positions of two points separated in the X direction by a distance corresponding to the size of the recording medium M being used, centered on the said center, are acquired. Then, a predetermined range centered on one of these positions is set as the detection range corresponding to one end, and a predetermined range centered on the other position is set as the detection range corresponding to the other end.

[0143] The predetermined range is determined, for example, according to the distance between the first light-receiving unit 322 and the second light-receiving unit 324. Specifically, the predetermined range is set to be, for example, longer by a predetermined amount than the distance. If the second sensor 38 is configured to detect only one end of the recording medium M, then only the detection range corresponding to that one end will be set.

[0144] =Retrieval process= Next, in this embodiment, the acquisition process for acquiring the edge of the recording medium M from the differential signal Vout of the differential amplifier 332 in differential mode will be described. Note that the acquisition process described below starts after the scan accompanied by the nth recording in S1104 has started in the recording process described above, and is executed, for example, in S1108.

[0145] Figure 23 is a flowchart detailing the acquisition process in this embodiment, which acquires the edge of the recording medium M from the differential signal Vout. The series of processes shown in the flowchart of Figure 23 are performed by the main controller 400, which loads the program code stored in the Flash ROM 402 into the RAM 404 and executes it. Alternatively, some or all of the functions of the steps in Figure 23 may be performed by hardware such as an ASIC or electrical circuit.

[0146] When the acquisition process begins, first, in S2302, the main controller 400 determines whether the differential signal Vout of the acquired differential amplifier 332 has passed the first threshold Th1. In S2304, if it is determined that the differential signal Vout has not passed the first threshold Th1, the process proceeds to S2310, which will be described later. Also, in S2302, if it is determined that the differential signal Vout has passed the first threshold Th1, the process proceeds to S2304, where the main controller 400 determines whether the most recently acquired coordinates are the first coordinates.

[0147] In S2304, if it is determined that the most recently acquired coordinate is not the first coordinate, the process proceeds to S2306, where the main controller 400 retains the coordinate acquired in S2302 as the first coordinate and proceeds to S2310. Alternatively, if it is determined in S2304 that the most recently acquired coordinate is the first coordinate, the process proceeds to S2308, where the main controller 400 retains the coordinate acquired in S2302 as the second coordinate and proceeds to S2310. In S2308, the retained second coordinate is associated with the most recently acquired first coordinate.

[0148] In S2310, the main controller 400 determines whether the carriage 32 has moved to the stopping position. Note that the specific processing content from S2302 to S2310 is the same as that from S1402 to S1410 described above, so a detailed explanation is omitted. If it is determined in S2310 that the carriage has not moved to the stopping position, the process returns to S2302. If it is determined in S2310 that the carriage has moved to the stopping position, the process proceeds to S2312, where the main controller 400 selects one pair of the acquired first and second coordinates as the true coordinate value based on a pre-set detection range.

[0149] In S2312, the first and second coordinates, which are associated with each other and both within the detection range, are obtained as the true values ​​of the coordinates. The detection range is stored in the memory area. Subsequently, in S2314, the main controller 400 obtains the edge of the recording medium M from the first and second coordinates, which have been set as true values, and terminates this acquisition process. The specific processing content of S2314 is the same as that of S1414 described above, so a detailed explanation is omitted.

[0150] =Modified Version= In the acquisition process shown in Figure 23, the coordinates that have passed the first threshold Th1 are acquired, and the position of the edge of the recording medium M is acquired based on the two associated coordinates within the detection range, but the process is not limited to this. For example, the process may be configured to monitor whether or not the device has entered the detection range, and if it has entered the detection range, the coordinates that have passed the first threshold Th1 are acquired, while if it has not entered the detection range, the coordinates are not acquired. Also, in the process of S2312, if multiple pairs of associated first and second coordinates are generated within the detection range, for example, using the technique of the second embodiment described above, the coordinates of the pair whose distance between the two coordinates is closest to the theoretical value may be acquired as the true value.

[0151] <Second form> Next, a second embodiment of the fifth embodiment will be described. As explained in the second embodiment described above, in the output waveform of the differential amplifier 332, minute pulses may be formed near the pulse corresponding to the edge of the recording medium M due to fluctuations or noise in the sensor signal. Due to the influence of these minute pulses, there is a risk that the edge of the recording medium M in the X direction may not be accurately detected. Specifically, for example, there is a risk that the midpoint of the two points that have passed the first threshold Th1 in the first minute pulse may be acquired as the edge of the recording medium M (see Figure 24(a)). Figure 24(a) is a diagram showing the output waveform representing the change in the differential signal Vout, in which minute pulses (chattering) are formed near the pulse waveform corresponding to the edge of the recording medium M.

[0152] =Specific technology in this form= Therefore, in the second embodiment, within the detection range set in the first embodiment, the midpoint between the position (point) where the first threshold Th1 is exceeded and the position (point) where the first threshold Th1 is last exceeded is acquired as the edge position of the recording medium M in the X direction (see Figure 24(b)). In this case, for example, in the acquisition process in Figure 23, it is not necessary to associate the second coordinate held in S2308 with the most recently acquired first coordinate. Also, in S2312, the first first coordinate and the last second coordinate acquired within the detection range are acquired as the true values ​​of the coordinates.

[0153] Furthermore, in this case, the distance between coordinates obtained as the true value is greater than the width of the pulse corresponding to the edge of the recording medium M, due to the minute pulses generated before and after the pulse corresponding to the edge of the recording medium M. The error becomes larger. However, if the second form of technology is not used, the error is smaller compared to when the midpoint between two points that pass the first threshold Th1 in the initially generated minute pulse is acquired as the position of the edge of the recording medium M (see Figure 24(c)). Also, because chattering is fast (short duration), even if the chattering portion is included in the pulse targeted for detection (the two points for acquiring the midpoint), the error is negligible.

[0154] As a result, in the second embodiment of the technology, the position of the edge of the recording medium M is no longer detected based on, for example, the first minute pulse that occurs within the detection range (see Figure 24(c)). Furthermore, the position of the edge of the recording medium M is no longer detected based on the last position that falls below the threshold after moving out of the detection range (see Figure 24(d)).

[0155] <Third form> Next, a third embodiment according to the fifth embodiment will be described. The differential signal Vout may degrade due to the influence of light reflection caused by dirt on the platen 34, and the distance between the point where the threshold is first passed and the point where the threshold is last passed may become shorter or longer than the distance when no signal degradation occurs. In this case, the position of the edge of the recording medium M cannot be accurately detected.

[0156] =Specific technology in this form= Therefore, in the third embodiment, the pulse width of the pulse corresponding to the edge of the recording medium M is set, and when the pulse width of the pulse acquired by detection is shorter (or longer) than the set pulse width, the acquired pulse width is corrected. The details will be explained below with reference to Figure 25. Figure 25 is a diagram illustrating the specific technical content of the third embodiment of the fifth embodiment, where (a) is a diagram illustrating the technique when the pulse width acquired by detection is short, and (b) is a diagram illustrating the technique when the pulse width acquired by detection is long.

[0157] Specifically, the pulse width of the pulse corresponding to the edge of the recording medium M is set based on the positional relationship between the first light-receiving unit 322 and the second light-receiving unit 324, that is, the distance between the center position of the first light-receiving unit 322 and the center position of the second light-receiving unit 324 in the X direction. A set value (set range) is set as the range in which the distance between the position where the pulse corresponding to the edge of the recording medium M exceeds the first threshold Th1 and the position where it falls below the first threshold Th1 is considered an acceptable distance. In addition, a correction value is set to correct for the position where it falls below the first threshold Th1. This correction value is a value that corresponds to the positional relationship between the first light-receiving unit 322 and the second light-receiving unit 324, and for example, it is a value that separates the position where it falls below the first threshold Th1 from the position where it exceeds the first threshold Th1 by a distance that allows the position of the edge of the recording medium M to be properly acquired. Note that this correction value is at least within the range set as the set value. This correction value is determined experimentally, for example, depending on the type of recording medium M.

[0158] Suppose the pulse width corresponding to the edge of the recording medium M, obtained by detection, is smaller than the set lower limit of pulse width between the position above the first threshold Th1 and the position below the first threshold Th1. In this case, the position below the first threshold Th1 is moved away from the position above the first threshold Th1 based on the set correction value, so that the distance between the position above the first threshold Th1 and the position below the first threshold Th1 becomes the correction value (see Figure 25(a)). Subsequently, the edge position of the recording medium M is obtained based on the position above the first threshold Th1 and the position below the first threshold Th1 after the movement. That is, in this case, by correcting the position below the first threshold Th1 with respect to the position above the first threshold Th1 based on the correction value, the distance between the position above the first threshold Th1 and the position below the first threshold Th1 becomes larger than before the correction.

[0159] Furthermore, suppose that the distance between the position where the pulse corresponding to the edge of the recording medium M, obtained by detection, exceeds the first threshold Th1 and the position where it falls below the first threshold Th1, is greater than the set upper limit of the pulse width. In this case, the position below the first threshold Th1 is moved towards the position exceeding the first threshold Th1 based on the set correction value, so that the distance between the position exceeding the first threshold Th1 and the position below the first threshold Th1 becomes the correction value (see Figure 25(b)). Subsequently, the edge position of the recording medium M is obtained based on the position exceeding the first threshold Th1 and the position below the first threshold Th1 after the movement. That is, in this case, by correcting the position below the first threshold Th1 with respect to the position exceeding the first threshold Th1 based on the correction value, the distance between the position exceeding the first threshold Th1 and the position below the first threshold Th1 becomes smaller than before the correction.

[0160] In other words, if the distance between the position where the pulse width exceeds the first threshold Th1 and the position where it falls below the first threshold Th1 is outside the range of the set value, the position where it falls below the first threshold Th1 will be moved to a position that is a correction value away from the position where it exceeds the first threshold Th1. Note that when the second form of technology described above is used in combination, the "position where the first threshold Th1 is exceeded" in the above explanation becomes the "position where the first threshold Th1 is first exceeded," and the "position where it falls below the first threshold Th1" in the above explanation becomes the "position where it falls below the first threshold Th1 last."

[0161] In the above explanation, if the distance between the position above the first threshold Th1 and the position below the first threshold Th1 is outside the range of the set value, the position below the first threshold Th1 is moved. However, it is not limited to this. The position above the first threshold Th1 may be moved to a position that is a correction value away from the position below the first threshold Th1. For example, if the platen 34 is dirtier than the recording medium M, when the second sensor 38 detects the edge of the recording medium M while moving from the recording medium M side to the platen 34 side in the X direction, the position below the first threshold Th1 is moved. Also, in this case, when the second sensor 38 detects the edge of the recording medium M while moving from the platen 34 side to the recording medium M side in the X direction, the position above the first threshold Th1 is moved.

[0162] <Effects and Effects> As described above, in the first embodiment of this embodiment, a detection range is provided for detecting pulses corresponding to the edge of the recording medium M, and pulses formed beyond the detection range are excluded when acquiring the position of the edge of the recording medium M. In the second embodiment of this embodiment, the coordinates of the midpoint between the position where the first threshold Th1 is exceeded and the position where the first threshold Th1 is finally exceeded within the detection range are acquired as the position of the edge of the recording medium M. Furthermore, in the third embodiment of this embodiment, if the width of the pulse corresponding to the edge of the recording medium M does not reach the lower limit or upper limit of the set value, the position where the first threshold Th1 is exceeded is moved based on the correction value. As a result, in this embodiment, even if an abnormality occurs in the output from the second sensor 38 or the differential amplifier 332, a position approximating the actual edge position of the recording medium M can be acquired as the edge position of the recording medium M.

[0163] (Other embodiments) This disclosure can also be implemented by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or recording medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0164] The above disclosure of embodiments includes the following configurations and methods. (Composition 1) Support means for supporting the recording medium being transported, A recording head is mounted on the recording medium for ejecting ink and recording, and a carriage is movable in the width direction of the recording medium intersecting the transport direction of the recording medium, The carriage includes a first detection means provided on one side in the width direction, which is capable of detecting the edge of the recording medium in the width direction, The carriage includes a second detection means provided on the other side in the width direction, which is capable of detecting the end of the recording medium in the width direction. At least one of the first detection means and the second detection means is The support means and the light-emitting means for irradiating the recording medium supported by the support means with light, The support means and the first light receiving means capable of receiving reflected light from the recording medium supported by the support means, A recording apparatus characterized by comprising: a second light-receiving means that overlaps with the first light-receiving means in the transport direction and is spaced apart in the width direction, and is capable of receiving reflected light from the support means and the recording medium supported by the support means. (Configuration 2) The recording device according to configuration 1, further comprising an output means for amplifying and outputting the difference between the output from the first light receiving means and the output from the second light receiving means. (Composition 3) The recording apparatus according to configuration 2, further comprising acquisition means for acquiring the end position of the recording medium in the width direction based on the output value of the output means when the carriage moves in the width direction. (Composition 4) The recording device according to configuration 3, wherein the acquisition means acquires the midpoint between two points where the output value from the output means has passed a threshold, and uses this midpoint as the end position. (Composition 5) The first detection means and the second detection means, comprising the light-emitting means, the first light-receiving means, and the second light-receiving means, The recording apparatus according to configuration 1, characterized in that, in the width direction, a third light-receiving means capable of receiving reflected light from the support means and the recording medium supported by the support means is provided between the first light-receiving means and the second light-receiving means. (Composition 6) The system further comprises output means for amplifying and outputting the outputs from the first light receiving means, the second light receiving means, and the third light receiving means. The output means is A first amplification means that amplifies the difference between the output from the first light receiving means and the output from the second light receiving means, The recording device according to configuration 5, further comprising a second amplification means that amplifies and outputs the output from the third light receiving means. (Composition 7) The system further includes an acquisition means for acquiring the end position of the recording medium in the width direction based on the output value from the output means when the carriage moves in the width direction. The acquisition means is, The output value from the first amplification means is obtained by taking the midpoint between two points that have passed the first threshold as the end position. The recording device according to configuration 6, characterized in that the point at which the output value from the second amplification means passes the second threshold is acquired as the end position. (Composition 8) The system further includes a recording control means that alternately performs a first recording, in which ink is ejected from the recording head while the carriage is moved in a first direction from one side to the other in the width direction, and a second recording, in which ink is ejected from the recording head while the carriage is moved in a second direction from the other side to the one side in the width direction. The first detection means, when performing the second recording, detects the first end located on one side of the recording medium in the width direction, The recording apparatus according to any one of configurations 1 to 7, characterized in that the second detection means detects the second end located on the other side of the recording medium in the width direction when performing the first recording. (Composition 9) An acquisition means that acquires the position of the first end based on the detection result of the first detection means and acquires the position of the second end based on the detection result of the second detection means, The recording device according to configuration 8, further comprising: a determination means for determining the position of the first end obtained by the acquisition means as the recording start position for the next recording, when the first recording is performed; and a determination means for determining the position of the second end obtained by the acquisition means as the recording start position for the next recording, when the second recording is performed. (Composition 10) The acquisition means is, Two corresponding points where the output value from the output means has passed the threshold are considered as a pair. The recording device according to configuration 4, characterized in that the midpoint of two points whose distance from the output means passes the threshold is closest to a predetermined value is acquired as the end position. (Composition 11) Two corresponding points where the output value from the aforementioned extraction output stage has passed the threshold are considered as a pair. The recording device according to configuration 4, characterized in that the acquisition means acquires the midpoint between two points where the difference between the distance between the two points that form a pair, in which the output value from the output means has passed the threshold, and a predetermined value is less than or equal to a first value, as the end position. (Composition 12) The recording device according to configuration 10 or 11, characterized in that the predetermined value is the distance between the first light-receiving means and the second light-receiving means in the width direction. (Composition 13) The recording device according to configuration 11, characterized in that the first value is a predetermined ratio to the predetermined value. (Composition 14) While moving the carriage in a predetermined direction from one side to the other in the width direction, and performing recording by ejecting ink from the recording head, the first detection means further has a changing means for changing the set stopping position of the carriage to the downstream side in the predetermined direction when detecting one end of the recording medium in the width direction. The first detection means is, The support means and the light-emitting unit that irradiates light onto the recording medium supported by the support means, The recording apparatus according to configuration 1, comprising the support means and a light receiving unit capable of receiving reflected light from the recording medium supported by the support means. (Composition 15) The stopping position changed by the aforementioned changing means is separated by a predetermined distance from the position corresponding to the end, The recording device according to configuration 14, characterized in that the predetermined distance is the distance from when the carriage starts to decelerate until it stops, or a distance that is a certain amount longer than said distance. (Composition 16) The recording device according to configuration 15, characterized in that the position corresponding to the end is the position of the end obtained based on the detection result detected by the first detection means during the most recent operation. (Composition 17) The first detection means is, The support means and the light-emitting unit that irradiates light onto the recording medium supported by the support means, The system comprises the support means and a light receiving unit capable of receiving reflected light from the recording medium supported by the support means, The recording device is An acquisition means for acquiring the point at which the output from the light receiving unit passes a threshold as the position of one end of the recording medium in the width direction, The recording device according to configuration 1, further comprising a correction means for correcting the end position acquired by the acquisition means. (Composition 18) The recording device according to configuration 17, characterized in that the correction means determines a correction amount based on the difference between the moving speed of the carriage when the first detection means passes the end and the reference speed. (Composition 19) The recording device according to configuration 18, characterized in that the movement speed of the carriage when the first detection means passes the end is acquired based on recording conditions. (Composition 20) While moving the carriage in a predetermined direction from the other side to the one side in the width direction, and performing recording by ejecting ink from the recording head, the first detection means further has a changing means for changing the set stopping position of the carriage to the downstream side in the predetermined direction when detecting the end. When the carriage's movement speed as the first detection means passes the end is lower than a predetermined speed, the changing means changes the stopping position. The recording device according to configuration 19, characterized in that when the carriage's movement speed when the first detection means passes the end is greater than or equal to the predetermined speed, the correction means corrects the end position. (Composition 21) Support means for supporting the recording medium being transported, A recording head is mounted on the recording medium for ejecting ink and recording, and a carriage is movable in the width direction of the recording medium intersecting the transport direction of the recording medium, The carriage includes a first detection means provided on one side in the width direction, which is capable of detecting the edge of the recording medium in the width direction, The carriage includes a second detection means provided on the other side in the width direction, which is capable of detecting the end of the recording medium in the width direction. At least one of the first detection means and the second detection means is The support means and the light-emitting means for irradiating the recording medium supported by the support means with light, The support means and the first light receiving means capable of receiving reflected light from the recording medium supported by the support means, A control method for a recording device comprising: a first light-receiving means, which overlaps with the transport direction and is spaced apart in the width direction, and which is capable of receiving reflected light from the support means and the recording medium supported by the support means, When performing a first recording in which ink is ejected from the recording head while moving the carriage in the direction from the other side to the one side in the width direction, the first detection means detects the first end located on one side of the recording medium in the width direction. A control method characterized in that, when performing a second recording in which ink is ejected from the recording head while moving the carriage in the width direction from one side to the other, the second detection means detects the second end located on the other side of the recording medium in the width direction. (Composition 22) The control method according to configuration 21, characterized in that the position of the first end obtained based on the detection result of the first detection means is set as the recording start position when the second recording is performed immediately afterward, and the position of the second end obtained based on the detection result of the second detection means is set as the recording start position when the first recording is performed immediately afterward. (Composition 23) The recording device according to configuration 4, characterized in that the acquisition means acquires the midpoint between two corresponding points where the output value from the output means passes the threshold within the detection range for detecting the end position, as the end position. (Composition 24) The recording device according to configuration 4, characterized in that the acquisition means acquires the midpoint between the point where the output value from the output means first exceeds the threshold and the point where the output value from the output means last falls below the threshold, within the detection range for detecting the end position, as the end position. (Composition 25) The recording apparatus according to configuration 23 or 24, characterized in that the detection range is set based on the transport position of the recording medium and the size of the recording medium, or the detection result of the transported recording medium by the first detection means or the second detection means. (Composition 26) The acquisition means is, A first point in which the output value from the output means exceeds the threshold, and a second point immediately following the first point in which the output value falls below the threshold, are considered to be a corresponding pair. The recording device according to configuration 4, characterized in that, if the distance between two points of a corresponding pair is outside the set range, the second point is moved to a position a predetermined value away from the first point, and the midpoint between the first point and the moved second point is obtained as the end position. (Composition 27) The acquisition means is, A first point in which the output value from the output means exceeds the threshold, and a second point immediately following the first point in which the output value falls below the threshold, are considered to be a corresponding pair. The recording device according to configuration 4, characterized in that, if the distance between two points of a corresponding pair is outside a set range, the first point is moved to a position a predetermined value away from the second point, and the midpoint between the first point and the second point after the move is acquired as the end position. (Composition 28) The recording device according to configuration 26 or 27, characterized in that the setting range is a value corresponding to the distance between the first detection means and the second detection means in the width direction, and is a range of distances from the first point in which the end position can be obtained. (Composition 29) The recording device according to configuration 26 or 27, characterized in that the predetermined value is a value such that the second point is separated from the first point by a distance that allows the end position to be obtained, depending on the positional relationship between the first detection means and the second detection means. [Explanation of Symbols]

[0165] 10 Recording device 12 recording heads 32 Carriage 34 Platen 36. First Sensor 38. Second Sensor 312 Light-emitting part 322 1st light receiving section 324 2nd light receiving section

Claims

1. Support means for supporting the recording medium being transported, A recording head is mounted on the recording medium for ejecting ink and recording, and a carriage is movable in the width direction of the recording medium intersecting the transport direction of the recording medium, The carriage includes a first detection means provided on one side in the width direction, which is capable of detecting the end of the recording medium in the width direction, The carriage includes a second detection means provided on the other side in the width direction, which is capable of detecting the end of the recording medium in the width direction. At least one of the first detection means and the second detection means is The support means and the light-emitting means for irradiating the recording medium supported by the support means with light, The support means and the first light receiving means capable of receiving reflected light from the recording medium supported by the support means, A recording apparatus characterized by comprising: a second light-receiving means that overlaps with the first light-receiving means in the transport direction and is spaced apart in the width direction, and is capable of receiving reflected light from the support means and the recording medium supported by the support means.

2. The recording apparatus according to claim 1, further comprising an output means for amplifying and outputting the difference between the output from the first light receiving means and the output from the second light receiving means.

3. The recording apparatus according to claim 2, further comprising acquisition means for acquiring the end position of the recording medium in the width direction based on the output value of the output means when the carriage moves in the width direction.

4. The recording device according to claim 3, wherein the acquisition means acquires the midpoint between two points where the output value from the output means has passed a threshold, and uses this midpoint as the end position.

5. The first detection means and the second detection means, comprising the light-emitting means, the first light-receiving means, and the second light-receiving means, The recording apparatus according to claim 1, characterized in that, in the width direction, a third light-receiving means capable of receiving reflected light from the support means and the recording medium supported by the support means is provided between the first light-receiving means and the second light-receiving means.

6. The system further includes an output means that amplifies and outputs the outputs from the first light receiving means, the second light receiving means, and the third light receiving means. The output means is A first amplification means that amplifies the difference between the output from the first light receiving means and the output from the second light receiving means, The recording apparatus according to claim 5, further comprising a second amplification means that amplifies and outputs the output from the third light receiving means.

7. The system further includes an acquisition means for acquiring the end position of the recording medium in the width direction based on the output value from the output means when the carriage moves in the width direction. The acquisition means is, The output value from the first amplification means is obtained by taking the midpoint between two points that have passed the first threshold as the end position. The recording device according to claim 6, characterized in that the point at which the output value from the second amplification means passes the second threshold is acquired as the end position.

8. The system further includes a recording control means that alternately performs a first recording, in which ink is ejected from the recording head while the carriage is moved in a first direction from one side to the other in the width direction, and a second recording, in which ink is ejected from the recording head while the carriage is moved in a second direction from the other side to the one side in the width direction. The first detection means, when performing the second recording, detects the first end located on one side of the recording medium in the width direction, The recording apparatus according to claim 1, characterized in that the second detection means detects the second end located on the other side of the recording medium in the width direction when performing the first recording.

9. An acquisition means that acquires the position of the first end based on the detection result of the first detection means and acquires the position of the second end based on the detection result of the second detection means, The recording apparatus according to claim 8, further comprising: a determination means for determining the position of the first end obtained by the acquisition means as the recording start position for the next recording, when the first recording is performed; and a determination means for determining the position of the second end obtained by the acquisition means as the recording start position for the next recording, when the second recording is performed.

10. The acquisition means is, Two corresponding points where the output value from the output means has passed the threshold are considered as a pair. The recording device according to claim 4, characterized in that the midpoint of the pair of points whose distance from the output means passes the threshold is closest to a predetermined value is acquired as the end position.

11. Two corresponding points where the output value from the output means has passed the threshold are considered as a pair. The recording device according to claim 4, characterized in that the acquisition means acquires the midpoint between two points where the difference between the distance between the two points that form a pair, in which the output value from the output means has passed the threshold, and a predetermined value is less than or equal to a first value, as the end position.

12. The recording device according to claim 10 or 11, characterized in that the predetermined value is the distance between the first light-receiving means and the second light-receiving means in the width direction.

13. The recording device according to claim 11, characterized in that the first value is a predetermined ratio to the predetermined value.

14. While moving the carriage in a predetermined direction from the other side to the one side in the width direction, and performing recording by ejecting ink from the recording head, the first detection means further includes a changing means for changing the set stopping position of the carriage to the downstream side in the predetermined direction when detecting one end of the recording medium in the width direction. The first detection means is, The support means and the light-emitting unit that irradiates light onto the recording medium supported by the support means, The recording apparatus according to claim 1, further comprising the support means and a light receiving unit capable of receiving reflected light from the recording medium supported by the support means.

15. The stopping position changed by the aforementioned changing means is separated by a predetermined distance from the position corresponding to the end, The recording device according to claim 14, characterized in that the predetermined distance is the distance from when the carriage starts to decelerate until it stops, or a distance that is a certain amount longer than said distance.

16. The recording device according to claim 15, characterized in that the position corresponding to the end is the position of the end obtained based on the detection result detected by the first detection means during the most recent operation.

17. The first detection means is, The support means and the light-emitting unit that irradiates light onto the recording medium supported by the support means, The system comprises the support means and a light receiving unit capable of receiving reflected light from the recording medium supported by the support means, The recording device is An acquisition means for acquiring the point at which the output from the light receiving unit passes a threshold as the position of one end of the recording medium in the width direction, The recording device according to claim 1, further comprising a correction means for correcting the end position acquired by the acquisition means.

18. The recording device according to claim 17, characterized in that the correction means determines a correction amount based on the difference between the moving speed of the carriage when the first detection means passes the end and the reference speed.

19. The recording device according to claim 18, characterized in that the movement speed of the carriage when the first detection means passes the end is acquired based on recording conditions.

20. The device further includes a changing means for changing the set stopping position of the carriage to the downstream side in the predetermined direction when, while performing recording by ejecting ink from the recording head while moving the carriage in a predetermined direction from the other side to the one side in the width direction, the first detection means detects the end, When the carriage's movement speed as the first detection means passes the end is lower than a predetermined speed, the changing means changes the stopping position. The recording device according to claim 19, characterized in that when the carriage moves at a speed greater than or equal to the predetermined speed when the first detection means passes the end, the correction means corrects the end position.

21. Support means for supporting the recording medium being transported, A recording head is mounted on the recording medium for ejecting ink and recording, and a carriage is movable in the width direction of the recording medium intersecting the transport direction of the recording medium, The carriage includes a first detection means provided on one side in the width direction, which is capable of detecting the end of the recording medium in the width direction, The carriage includes a second detection means provided on the other side in the width direction, which is capable of detecting the end of the recording medium in the width direction. At least one of the first detection means and the second detection means is The support means and the light-emitting means for irradiating the recording medium supported by the support means with light, The support means and the first light receiving means capable of receiving reflected light from the recording medium supported by the support means, A control method for a recording device comprising: a first light-receiving means, which overlaps with the transport direction and is spaced apart in the width direction, and which is capable of receiving reflected light from the support means and the recording medium supported by the support means, When performing a first recording in which ink is ejected from the recording head while moving the carriage in the direction from the other side to the one side in the width direction, the first detection means detects the first end located on one side of the recording medium in the width direction. A control method characterized in that, when performing a second recording in which ink is ejected from the recording head while moving the carriage in the width direction from one side to the other, the second detection means detects the second end located on the other side of the recording medium in the width direction.

22. The control method according to claim 21, characterized in that the position of the first end obtained based on the detection result of the first detection means is set as the recording start position when the second recording is performed immediately afterward, and the position of the second end obtained based on the detection result of the second detection means is set as the recording start position when the first recording is performed immediately afterward.

23. The recording device according to claim 4, characterized in that the acquisition means acquires the midpoint between two corresponding points in the detection range for detecting the end position, where the output value from the output means has passed the threshold, as the end position.

24. The recording device according to claim 4, characterized in that the acquisition means acquires the midpoint between the point where the output value from the output means first exceeds the threshold and the point where the output value from the output means last falls below the threshold, within the detection range for detecting the end position, as the end position.

25. The recording apparatus according to claim 23 or 24, characterized in that the detection range is set based on the transport position of the recording medium and the size of the recording medium, or the detection result of the transported recording medium by the first detection means or the second detection means.

26. The acquisition means is, A first point in which the output value from the output means exceeds the threshold, and a second point immediately following the first point in which the output value falls below the threshold, are considered to be a corresponding pair. The recording device according to claim 4, characterized in that, if the distance between two points of a corresponding pair is outside the set range, the second point is moved to a position a predetermined value away from the first point, and the midpoint between the first point and the second point after the move is obtained as the end position.

27. The acquisition means is, A first point in which the output value from the output means exceeds the threshold, and a second point immediately following the first point in which the output value falls below the threshold, are considered to be a corresponding pair. The recording device according to claim 4, characterized in that, if the distance between two points of a corresponding pair is outside a set range, the first point is moved to a position a predetermined value away from the second point, and the midpoint of the first point and the second point after the move is obtained as the end position.

28. The recording device according to claim 26 or 27, characterized in that the setting range is a value corresponding to the distance between the first detection means and the second detection means in the width direction, and is a range of distances from the first point in which the end position can be obtained.

29. The recording device according to claim 26 or 27, characterized in that the predetermined value is a value such that the second point is separated from the first point by a distance such that the end position can be obtained, depending on the positional relationship between the first detection means and the second detection means.

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