JP5837328B2 - Recording device - Google Patents

Description

The present invention relates to a recording apparatus having an edge detecting equipment for detecting the edge of the recording medium.

  2. Description of the Related Art Conventionally, inkjet printers that perform printing while scanning a recording head in a horizontal direction (main scanning direction) while intermittently feeding recording paper as a recording medium in the vertical direction (sub-scanning direction). Are known.

  This printer includes an edge detection device for detecting the left and right edges of a recording sheet set on a platen in order to detect the lateral width of the recording sheet and to detect a lateral shift (skew) of the recording sheet. Is provided.

Here, a conventional edge detection apparatus will be briefly described.
In the edge detection device, an edge detection photosensor such as a reflective photomicrosensor is provided on the carriage so as to face the platen.

  The edge detection device scans the carriage laterally so that the photosensor crosses the edge of the recording paper in a state of facing the recording paper set on the platen, and the reflected light amount of the recording paper and the recording paper are separated from the recording paper. The point at which the sensor output of the photosensor has changed below a predetermined threshold due to the difference from the non-reflective tape on the platen at the position has been detected as the edge of the recording paper.

  Specifically, the CPU in the edge detection device acquires the sensor output of the photosensor at a predetermined cycle (for example, 10 ms cycle), compares the sensor output with a predetermined threshold value, and detects the edge of the recording paper. Was.

  In addition, Japanese Patent Application Laid-Open No. 2007-210747 discloses that a step response from a photosensor when crossing an edge of a recording sheet is AC-coupled into a differential waveform so that edge detection is possible even during printing, and is amplified and filtered by an operational amplifier. After that, it has been proposed to detect the differential waveform with a comparator.

JP 2007-210747 A

  However, in the conventional method, since the sensor output of the photosensor is acquired at a predetermined cycle (for example, a cycle of 10 ms), the distance that the photosensor moves during the predetermined cycle increases as the carriage moving speed increases. Therefore, as the carriage moving speed increases, the edge detection accuracy decreases.

  For this reason, when a conventional printer with an edge detection device detects the edge of a recording sheet, the carriage movement speed is made slower than the movement speed during printing to maintain the accuracy of edge detection. Therefore, edge detection cannot be performed while moving the carriage at high speed during printing, and throughput and check frequency are reduced.

  In addition, since the light reception level of the reflected light on the non-reflective tape on the platen and the light reception level of the reflected light on the recording paper are compared with the threshold value based on the light reception level itself, if the difference between these light reception levels is small ( For example, when the recording paper is tracing paper), the difference between the received light level and the threshold value becomes small, and the edge of the recording paper cannot be detected accurately.

  In addition, there is a variation in sensitivity in the sensor itself. If the light emission current and the light reception sensitivity of the sensor are made variable to absorb this, it takes time to select them.

  Further, in the method of detecting an edge during printing proposed in Japanese Patent Application Laid-Open No. 2007-210747, when a recording sheet having a rough surface state or a hole such as a mesh medium is used, recording is performed. There is a possibility that an appropriate edge position cannot be detected because any part on the paper is detected as an edge.

  In the method of detecting the edge during printing, the directions of the impulse signals output from the non-reflective tape to the recording paper and the edges of the non-reflective tape from the recording paper are reversed while the carriage performs one scan. Only one of the edges can be detected.

The recording apparatus of the present invention is an edge detection apparatus that detects an edge of a recording medium on which printing is performed, and the sensor outputs a first level signal when the recording medium is in a detection area. When the recording medium is not present in the detection area, a second level signal different from the first level is output, and the sensor is transported so that the detection area of the sensor crosses the edge of the recording medium. A transfer unit, an output generation unit that outputs a change detection signal obtained by amplifying the signal through a band-pass filter when the level of the signal output from the sensor changes, and the change detection signal output by the output generation unit. Each threshold voltage when the recording medium moves from a position where there is no recording medium to a certain position and when it moves from a position where there is no recording medium to a position where there is no change with respect to any change in the signal in the rising or falling direction. A control unit that detects the edge of the recording medium based on the result of comparison with the position detection unit that detects a linear scale arranged along the moving direction of the transport unit and detects the position of the sensor; A memory for extracting and storing a position detected by the position detecting means when the edge of the recording medium is detected by the edge detection control unit, and the recording based on the position stored in the memory An edge detection device that acquires the position of the edge of the medium, a print head that is mounted on the transport unit and performs printing on the recording medium, and controls and prints the print head based on the position of the edge The sensor includes a first sensor and a second sensor having different installation positions, and the detection area of the first sensor and the detection area of the second sensor are small. At least partly overlaps, the detection area of the first sensor is narrower than the detection area of the second sensor, the first sensor has a steeper change in the light receiving level than the second sensor, and the first sensor And the second sensor detects the edge at the same position of the recording medium, and the control unit that detects the edge based on signals output from the first sensor and the second sensor is configured to detect the edge of the recording medium. An edge is detected, and the edge detection device averages the edge position of the recording medium acquired based on the output of the first sensor and the position of the edge of the recording medium acquired based on the output of the second sensor. And the result of the calculation is used as the position of the edge of the recording medium .

  The change detection signal is output when the level of the signal output from the sensor changes. Therefore, even if the sensor output signal level difference between when the sensor detects the recording medium and when the sensor does not detect it is small, the change detection signal is output when the sensor detects the edge of the recording medium. Therefore, it is possible to detect an edge of a recording medium that could not be detected because the level difference between the output signals of the sensors is small.

  The output signal level of the sensor changes when the detection area of the sensor crosses the edge of the recording medium, and the rate of change in the level increases as the crossing speed increases. For this reason, even if the detection area of the sensor crosses the edge of the recording medium, the edge of the recording medium can be detected, and the speed of edge detection can be increased.

  In addition, since the edge of the recording medium can be detected during one scan of the carriage by detecting the edge of the recording medium with respect to any change in the change detection signal, the conventional method. In addition, the detection accuracy can be improved by increasing the number of samplings.

  In addition, it is detected only at the moment when the sensor crosses the edge of the recording medium after the sensor receives light reflected from the non-reflective tape outside the area where the recording medium is arranged, that is, within the carriage traveling range. The sensor records only after the selected edge is used, or the inside of the recording medium, that is, the sensor receives the reflected light from the recording medium, and the light receiving level is relatively unstable depending on the surface condition of the medium. By adopting only the last edge detected immediately before the state of receiving the reflected light from the non-reflective tape across the edge of the medium for a certain period, regardless of the surface state or type of the recording medium, Stable edge detection can be performed.

  In addition, by limiting the edge detection area in advance within the carriage travelable range, erroneous detection due to unexpected reflected light from other than the recording medium and the non-reflective tape can be prevented.

  Further, according to the above-described invention, the edge of the recording medium can be detected at high speed and with high accuracy, whereby printing can be accurately performed at a predetermined position on the recording medium.

  According to the present invention, since the edge of the recording medium is detected based on the change detection signal output when the level of the signal output from the sensor changes, the level difference between the sensor output signals is detected. It becomes possible to detect the edge of the recording medium that could not be done, and even if the detection area of the sensor increases the speed of crossing the edge of the recording medium, it does not depend on the surface state of the recording medium, and unexpected disturbance light etc. The edge of the recording medium can be detected without being affected by the above. Therefore, it is possible to increase the speed and accuracy of edge detection.

FIG. 1 is a block diagram showing a main configuration of a printer apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating an example of a paper transport mechanism of the printer apparatus. FIG. 3 is a block diagram illustrating an example of an edge detection mechanism of the printer apparatus. FIG. 4 is an explanatory diagram for explaining an example of setting the signal pass band of the band pass filter. FIG. 5 is a timing chart for explaining the operation of the printer apparatus. FIG. 6 is a configuration diagram showing an example of improving the edge detection accuracy by installing a plurality of sensors on the carriage. FIG. 7 is a configuration diagram showing an example of improving the edge detection accuracy by installing a plurality of sensors having different optical characteristics on the carriage. FIG. 8 is a schematic diagram of an example of sensors having different optical performances.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a main configuration of a printer apparatus according to an embodiment of the present invention.
In FIG. 1, a printer apparatus 1 intermittently feeds large-size paper (recording medium) such as A1 size, A0 size, and large-size roll paper in the vertical direction, and laterally moves a print head 60 that ejects ink in dots. This is an inkjet printer for large format paper that performs printing while scanning in the direction.

  The printer apparatus 1 includes a CPU 10, a paper feed motor driver 20, a paper feed motor 21, a carriage control motor driver 30, a carriage control motor 31, an edge sensor 40, a sensor control circuit 45, a print head 60, A head controller 65.

  The CPU 10 governs overall control of the printer apparatus 1. A program is stored in a memory connected to the CPU 10, and the CPU 10 operates according to the program to control the printer device 1. The paper feed motor 21 is a drive unit for feeding a paper as a recording medium in the vertical direction. The paper feed motor driver 20 controls driving of the motor 21. The print head 60 performs printing by ejecting ink dots. The head controller 65 ejects ink dots from the print head 60. The carriage control motor 31 is an example of a transport unit, and sends the print head 60 and the edge sensor 40 in the horizontal direction. The carriage control motor driver 30 controls driving of the carriage control motor 31.

  The edge sensor 40 outputs a first level signal when there is a sheet in its own detection area, and outputs a second level signal different from the first level when there is no sheet in the detection area. The edge sensor 40 is, for example, a photo sensor that detects reflected light from a sheet and reflected light from a non-reflective tape placed in a region on the platen. The sensor control circuit 45 processes a signal output from the edge sensor 40.

  FIG. 2 is a schematic diagram showing the mechanism of the transport system of the print head 60. In FIG. 2, the same components as those shown in FIG.

  In FIG. 2, the print head 60 is attached to a carriage 70 configured to be slidable in the horizontal direction, and the carriage 70 is slid in the horizontal direction to set the platen 53 and the sheet 5 set on the platen 53. The scan is moved in the horizontal direction above the.

  Further, the edge sensor 40 is attached to the side end of the carriage 70 in a state where the detection direction is directed to the platen 53 side, and scans with the print head 60.

  The carriage 70 is fixed to a steel belt 72 of a conveyance belt mechanism 71 that constitutes a conveyance unit, and a drive pulley 73 of the conveyance belt mechanism 71 is rotated by a carriage control motor 31, and then laterally passes through a timing belt 79 and a driven pulley 74. Move to slide.

  Further, the carriage 70 is provided with a linear sensor 75 for detecting the movement amount, and the linear sensor 75 detects a detection groove of the linear scale 76 that is fixedly arranged along the movement direction of the carriage 70. The movement amount of the carriage 70 is detected by counting the detection grooves.

  The detection output (count value) from the linear sensor 75 is input to the motor driver 30 of the carriage control motor 31 and the head control unit 65 of the print head 60, and is used for controlling the movement amount of the carriage 70, or the print head 60. It is used to control the ink ejection timing.

  FIG. 3 is a block diagram illustrating an example of an edge detection mechanism in the printer apparatus 1, specifically, an edge sensor 40, a sensor control circuit 45, and the CPU 10. In FIG. 3, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

  The edge sensor 40 includes a light emitting element 40a and an optical sensor 40b. The sensor control circuit 45 includes a capacitor C1, a resistor R1, an operational amplifier 45a, a capacitor C2, a resistor R2, a comparator 45b, a comparator 45c, and an FPGA (Field Programmable Gate Array) 45d.

  The light emitting element 40 a emits light toward the detection region of the edge sensor 40. The light emitting element 40a is connected in series with the resistor R3. The optical sensor 40b is connected in series with the resistor R4, and receives light reflected by an object in the detection region of the edge sensor 40.

  For this reason, the edge sensor 40 outputs a signal of a level corresponding to the amount of reflected light received by the optical sensor 40b from the terminal A. Specifically, the edge sensor 40 outputs a signal indicating a step response (level is high when there is no paper 5 and level is low when there is paper 5) when its detection area crosses the edge of the paper 5. Output.

  The capacitor C1 obtains an AC component (differential waveform) from this step response. The AC component is generated at the terminal A when the edge sensor 40 crosses the edge of the paper.

  The operational amplifier 45a has an inverting input terminal (− terminal) connected to the terminal A via the capacitor C1 and the resistor R1, a non-inverting input terminal (+ terminal) connected to the reference voltage Vref1, and an output terminal connected to the capacitor C2 and the resistor R2. Are connected to the inverting input terminal via a parallel circuit. The operational amplifier 45a amplifies the AC component extracted by the capacitor C1. The AC component amplified by the operational amplifier 45a is used as a change detection signal.

  The capacitor C1 and the resistor R1 form a high pass filter, and the capacitor C2 and the resistor R2 form a low pass filter. The capacitance of the capacitor C1 is c1, the resistance value of the resistor R1 is r1, the capacitance of the capacitor C2 is c2, and the resistance value of the resistor R2 is r2.

  By matching the pass band (fCL = 1 / 2πc1r1, fCH = 1 / 2πc2r2) of the bandpass filter constituted by this high-pass filter and this low-pass filter with the signal frequency of the differential waveform obtained by the capacitor C1. Unnecessary band components can be removed. The signal frequency of the differential waveform depends on the moving speed of the carriage.

FIG. 4 is an explanatory diagram for explaining an example of setting the passband of the bandpass filter.
As shown in FIG. 4, the passband (fCL to fCH) of the bandpass filter is desirably set according to the slope of the voltage change at the terminal A.

  The comparator 45b compares the output of the operational amplifier 45a with a threshold reference voltage Vref2, and generates a detection output when the output of the operational amplifier 45a is greater than the reference voltage Vref2. The comparator 45c compares the output of the operational amplifier 45a with a threshold reference voltage Vref3, and generates a detection output when the output of the operational amplifier 45a is smaller than the reference voltage Vref3.

  The FPGA 45d is an example of a control unit, and when the comparator 45b and the comparator 45c generate detection outputs, the detection output (count value) of the linear sensor 75 at that moment is stored in the built-in memory in hardware.

  The CPU 10 acquires the edge position of the paper 5 by reading the detection output (count value) of the linear sensor 75 stored in the FPGA 45d.

  The circuit formed by the capacitor C1, the resistor R1, the operational amplifier 45a, the capacitor C2, and the resistor R2 is an example of the output generator 45e, and when the signal level output from the edge sensor 40 changes, A change detection signal is output at terminal C. Terminal C is the output side of the OP amplifier, where it is AC coupled and amplified to obtain a filtered waveform. The output ADC is a means for obtaining a preliminary level.

Next, the operation will be described.
FIG. 5 is a timing chart for explaining the operation of the printer apparatus shown in FIG. Specifically, FIG. 5A is an explanatory diagram showing a relative positional relationship between the edge sensor 40, the platen 53, and the paper 5, and FIG. 5B is a voltage waveform at the terminal A. FIG. 5C is a voltage waveform at the terminal B, FIG. 5D is a change detection signal that is a voltage waveform at the terminal C, FIG. 5E is a detection output waveform of the comparator 45b, and FIG. 5E is a detection signal of the comparator 45c. The output waveform is shown.

  When the edge sensor 40 detects not the paper 5 but the platen 53 (non-reflective tape) (period T1), the high level (second level) is maintained at the terminal A. Therefore, the terminals B and C are held at the reference voltage Vref1.

  When the carriage 70 moves and the edge sensor 40 crosses the edge of the sheet 5 (timing T2), a step response occurs at the terminal A (see FIG. 5B).

The capacitor C1 extracts a differential component of this step response (see FIG. 5C).
This differential component is amplified by the operational amplifier 45a, and a frequency component related to edge detection is extracted from the differential component by a band-pass filter formed by the capacitor C1, the resistor R1, the capacitor C2, and the resistor R2 ( (Refer FIG.5 (d)).

  The comparator 45b compares the output of the operational amplifier 45a with a threshold reference voltage Vref2, and generates a detection output when the output of the operational amplifier 45a is greater than the reference voltage Vref2.

  When the comparator 45b generates a detection output, the FPGA 45d stores the detection output (count value) of the linear sensor 75 at that moment in the built-in memory in hardware. The CPU 10 acquires the edge position of the paper by reading the detection output (count value) of the linear sensor 75 stored in the FPGA 45d.

  After that, the carriage 70 moves, but when the edge sensor 40 detects the paper 5 (period T3), the terminal A maintains the low level (first level). Therefore, the terminals B and C are held at the reference voltage Vref1.

  When the carriage 70 further moves and the edge sensor 40 crosses the edge of the sheet 5 (timing T4), a step response occurs at the terminal A (see FIG. 5B).

The capacitor C1 extracts a differential component of this step response (see FIG. 5C).
This differential component is amplified by the operational amplifier 45a, and a frequency component related to edge detection is extracted from the differential component by a band-pass filter formed by the capacitor C1, the resistor R1, the capacitor C2, and the resistor R2 ( (Refer FIG.5 (d)).

  The comparator 45c compares the output of the operational amplifier 45a with a threshold reference voltage Vref3, and generates a detection output when the output of the operational amplifier 45a is smaller than the reference voltage Vref3.

  The FPGA 45d stores the detection output (count value) of the linear sensor 75 at the moment when the detection output of each of the comparator 45b and the comparator 45c, that is, the left and right edge positions of the paper 5 is stored in individual memory areas.

  The CPU 10 controls the operation of the print head 60 while confirming the position of the edge. For example, the CPU 10 determines the operation timing of the print head 60 based on the edge position.

  According to the present embodiment, the edge of the paper 5 is detected based on the change detection signal output at the terminal C when the level of the signal output from the edge sensor 40 changes.

  Therefore, it is possible to detect the edge of the paper (for example, tracing paper) that could not be detected because the level difference of the output signal of the edge sensor 40 is small, and the detection area of the edge sensor 40 is the edge of the paper 5. The edge of the paper 5 can be detected even when the speed of crossing is increased. A slight level difference can be emphasized by AC coupling and amplification as a differential waveform. That is, it is possible to detect the position where the edge of the waveform is raised with high accuracy instead of making a determination at the waveform level. Therefore, it is possible to increase the speed and accuracy of edge detection.

  In addition, since the bandpass filter is formed by the capacitor C1 and the resistor R1, and the capacitor C2 and the resistor R2 connected to the operational amplifier 45a, the illumination is flickering by low frequency noise (sunlight or commercial frequency (AC power supply)). ) And noise in the high frequency region (external light such as an inverter fluorescent lamp) can be cut off, and deterioration in edge detection accuracy can be prevented.

  Further, since the level change of the output signal of the edge sensor 40 is used as information used for edge detection, and the output signal level itself of the edge sensor 40 is not used, malfunction due to variations in sensitivity of the edge sensor 40 is unlikely to occur.

  Further, by using two comparators, that is, the comparator 45b and the comparator 45c, it is possible to detect any change in the output of the operational amplifier 45a, so that the sheet 5 is scanned during one scan of the carriage 70. Both left and right edges can be detected, and this is nothing more than double the number of times of sampling in the prior art, so that improvement in edge detection accuracy can be expected.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above-described embodiment, the edge sensor 40 having an optical sensor is used. However, as the edge sensor 40, a distance detection sensor that detects a distance to an object in the direction of the platen 53 may be used.

  Further, the state in which the edge sensor 40 receives the reflected light from the outside of the sheet 5, that is, from the platen 53 (non-reflective tape) within the travelable range of the carriage 70 (period T1 in FIG. 5D) continues for a certain period. After that, the FPGA 45d outputs the detection output (count value) of the linear sensor 75 only at the moment when the edge detected for the first time at the moment when the edge sensor 40 crosses the edge of the paper 5 (timing T2 in FIG. 5D). Light receiving level state that is relatively unstable depending on the surface state of the storage, or the edge sensor 40 receives the reflected light from the inside of the paper 5, that is, the paper 5, (period T3 in FIG. 5D) After that, when the edge sensor 40 receives the reflected light from the platen 53 (non-reflective tape) across the edge of the paper 5 for a certain period of time (FIG. 5 ( ), The FPGA 45d stores the detection output (count value) of the linear sensor 75 only at the moment when the last edge detected immediately before (T5 in FIG. 5D) is output in the period T5). Regardless of the surface state and type of the paper 5, stable edge detection can be performed.

  In addition, by limiting the area in which the edge is detected in advance within the travelable range of the carriage 70, it is possible to prevent erroneous detection due to unexpected reflected light from other than the paper 5 and the platen 53 (non-reflective tape).

  As shown in FIG. 6, a plurality of edge sensors 40 may be installed on the carriage. FIG. 6 shows the case where the edge sensors 40 are respectively installed at the left and right ends of the carriage 70. According to this, each time the carriage 70 scans on the paper 5, each edge sensor 40 moves on the edge of the paper 5. Edge detection is performed twice by crossing. In addition, the detection areas of the two edge sensors 40 are overlapped so that the edges of the same position of the paper 5 can be detected. By calculating the average of the detected edge positions, the edge position variation is reduced to 1 / √2 times that detected by the single edge sensor 40, so that the edge detection accuracy can be improved. Can do. Of course, the edge detection accuracy can be further improved by installing more edge sensors 40. If n sensors are used, each time the carriage 70 scans the paper 5, the edge detection is performed n times. By averaging these, the edge position variation is 1 / √n times. Can be reduced. Further, the respective edge sensors 40 may be arranged so as to be shifted in the transport direction of the paper 5 so as to detect edges at different positions of the paper 5. In this case, by acquiring edges at different positions of the paper 5 almost simultaneously, even if there is a problem specific to the detection position, for example, a problem that the paper 5 is notched, the influence of the problem is affected. Can be small.

  FIG. 7 shows an example in which an edge sensor 40 having different optical performance is installed. An example of the optical performance of the edge sensor 40a and the edge sensor 40b shown here is shown in FIG. FIG. 8A shows an example of an edge sensor with a narrow detection area, and FIG. 8B shows an example of an edge sensor with a wide detection area. In the edge sensor 40a, light beams 401a and 402a are narrowed by an optical lens, respectively. As a result, the detection range of the edge sensor 40a is narrowed as indicated by 403a. The edge sensor 40a can expect a sharp change in the received light level within a narrow detection range, and therefore can detect the edge position with high accuracy. However, when there are many specular reflection components on the surface of the detection body, depending on the inclination of the detection body, the light beam 401a on the light emission side does not return to the light beam 402a on the light reception side at an appropriate reflection angle, resulting in a large light reception level error There is. On the other hand, the edge sensor 40b has a light beam 401b and 402b spread by an optical lens. As a result, the detection range of the edge sensor 40b is as wide as 403a. Since the edge sensor 40b shows a gradual change in the received light level within a wide detection range, the detection accuracy is not high, but stable detection is possible regardless of the surface state of the detection body. The edge sensors 40 having different optical performances indicated by these 40a and 40b are installed close to each other as shown in FIG. 7, that is, the detection areas are arranged so that the detection areas of the edge sensor 40a and the edge sensor 40b are close to each other. Although the case where two sensors are mounted has been described, three or more sensors may be used. Of the two edge positions obtained each time the carriage 70 scans on the paper 5, the one with the light reception level obtained continuously is stable, for example, the one with little variation in detection output. The edge position can be detected stably for a wide range of surface conditions of the paper 5.

  In the above embodiment, a recording medium (medium) sheet is used. However, the recording medium is not limited to the recording sheet and can be changed as appropriate.

  In addition, the edge detection device of the present invention is not only applied to the detection of the edge of the recording medium in the width direction of the ink jet printer, but also can be usefully applied to various devices that need to specify the position of the recording medium. it can.

DESCRIPTION OF SYMBOLS 1 ... Printer apparatus, 10 ... CPU, 40 ... Edge sensor, 45 ... Sensor control circuit, 45a ... Operational amplifier, 45b ... Comparator, 45c ... Comparator, 45d ... FPGA, 53 ... Platen, 60 ... Print head, 70 ... Carriage, C1 ... Capacitor, C2 ... Capacitor, R1 ... Resistance, R2 ... Resistance

Claims (1)

An edge detection device that detects an edge of a recording medium on which printing is performed by a sensor,
The sensor outputs a first level signal when the recording medium is in the detection area, and outputs a second level signal different from the first level when the recording area is not present in the detection area,
A transport unit for transporting the sensor such that the detection area of the sensor crosses an edge of the recording medium;
An output generator for outputting a change detection signal obtained by amplifying the signal through a band-pass filter when the level of the signal output from the sensor changes;
When the recording medium is moved from a position where there is no recording medium to a position where the recording medium is moved with respect to any change in the rising or falling direction signal of the change detection signal output by the output generator A control unit for detecting the edge of the recording medium based on a result of comparison with each threshold voltage;
Position detecting means for detecting a linear scale arranged along the moving direction of the transport unit and detecting the position of the sensor;
A memory for extracting and storing a position detected by the position detecting means when the edge of the recording medium is detected by the edge detection control unit;
An edge detection device that acquires the position of the edge of the recording medium based on the position stored in the memory ;
A print head mounted on the transport unit for printing on the recording medium;
A print control unit that controls and prints the print head based on the position of the edge;
The sensor includes a first sensor and a second sensor having different installation positions, and at least a part of the detection area of the first sensor overlaps the detection area of the second sensor, and the detection area of the first sensor is the first sensor. The detection area of the first sensor is narrower than that of the second sensor. The first sensor and the second sensor detect the edge at the same position of the recording medium. The control unit that detects the edge based on signals output from the first sensor and the second sensor detects the edge of the recording medium,
The edge detection device calculates an average of the edge position of the recording medium acquired based on the output of the first sensor and the edge position of the recording medium acquired based on the output of the second sensor; A recording apparatus characterized in that a result of the calculation is set to the position of the edge of the recording medium .

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