JP2023175137A - recording device - Google Patents

Abstract

To provide a recording device that senses a width of a medium to be recorded medium using an optical sensor, which can calculate a threshold by which presence or absence of the medium to be recorded can be determined accurately, regardless of a kind of the medium to be recorded.SOLUTION: A recording device which is used comprises: a recording part that performs recording on a medium to be recorded; a conveying part that supports the medium to be recorded; a sensor part including an emitting and a light receiving part for reflected light; a scanning part that scans the sensor part in a width direction; and a control part that compares output of the light receiving part with a threshold to sense presence or absence of the medium to be recorded. The control part obtains a quantity of adjusted light at which output from the light receiving part becomes equal to target output, by making the emitting part emit light to the medium to be recorded while adjusting a quantity of emitted light, obtains output of the conveying part by emitting light using the quantity of adjusted light in a state where the medium to be recorded does not exist in front of the sensor part, and determines the threshold on the basis of the target output and the output of the conveying part.SELECTED DRAWING: Figure 4

Description

The present invention relates to a recording device.

Conventionally, in a recording device that transports and records on a recording medium such as paper, the width of the recording medium (paper width) is detected in order to prevent printing outside the area of the recording medium. There is. An example of this detection means is a mechanism that is capable of scanning in the width direction (a direction intersecting the conveyance direction of the recording medium) and has an optical sensor that irradiates light and receives reflected light from the recording medium. The amount of light received by the optical sensor changes based on the amount of light reflection. Therefore, by comparing an output signal based on the intensity of reflected light with a threshold value while scanning the optical sensor, the presence or absence of a recording medium can be detected, and as a result, the width of the recording medium can be detected.

In a recording device that uses such a detection means to detect the width of a recording medium, it is possible to determine whether the intensity of a signal output by an optical sensor according to the intensity of reflected light is a value indicating that a recording medium is present. It is necessary to set a threshold for determination. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 7-179248) discloses a technique in which, before detecting the recording medium width with an optical sensor, a preliminary detection operation similar to the detection operation is performed to preset the above threshold value. There is.

Japanese Unexamined Patent Publication No. 7-179248

FIG. 11 is a flowchart schematically showing the operation of the conventional example. When recording medium width detection is started in step S100, paper feeding operation is started in step S101. In the paper feeding detection in step S102, it is confirmed whether the paper has been fed to a certain position. If the determination result is No, paper feeding detection is performed again after a pause. If the determination result is Yes, in step S103, the recording medium is transported to a recording medium width detection position where it can be scanned by the optical sensor. In step S104, a preliminary detection operation is performed, and while scanning the optical sensor in the width direction, the outputs of the optical sensor in each of the recording medium portion and the portion other than the recording medium are acquired. If this obtained result is made into a frequency distribution for each output intensity, the distribution will have peaks for areas where there is a recording medium and areas where there is no recording medium. In step S105, a threshold value is calculated from the two peak levels by, for example, calculating an average value. In step S106, a paper width detection operation for the recording medium is performed using the calculated threshold value.

However, in such conventional techniques, depending on the type of recording medium, the difference between the output obtained from the area where the recording medium is present and the output obtained from the area where there is no recording medium may be small. As a result, even if the threshold value calculated based on the output obtained in the preliminary detection operation was used, it was not possible to accurately determine the presence or absence of a recording medium, and as a result, there was a problem that the detection accuracy of the recording medium width decreased. .

The present invention has been made in view of the above problems, and is capable of accurately determining the presence or absence of a recording medium regardless of the type of recording medium in a recording device that detects the width of a recording medium using an optical sensor. The purpose is to calculate such a threshold value.

The present invention employs the following configuration. That is,
a recording unit that records on a recording medium;
a conveyance unit that supports the recording medium being conveyed;
a sensor unit including an irradiation unit that irradiates irradiation light; and a light reception unit that receives reflected light and outputs a signal according to the intensity of the reflected light;
a scanning unit that scans the sensor unit in a width direction that intersects with a conveyance direction by the conveyance unit;
a control unit that detects the width of the recording medium by comparing the output from the light receiving unit with a threshold value to detect the presence or absence of the recording medium;
A recording device comprising:
The control unit includes:
By irradiating the recording medium from the irradiation unit while adjusting the intensity of the irradiation light, an adjusted light intensity is obtained such that the output from the light receiving unit becomes a target output,
By irradiating the irradiation light using the adjusted light amount in a state where the recording medium is not present in a range facing the sensor unit to be scanned, the light receiving unit can detect light from the light receiving unit based on the reflected light from the transport unit. Obtaining the transport unit output which is the output,
The recording apparatus is characterized in that the threshold value for detecting the presence or absence of the recording medium is determined based on the target output and the output of the conveying section.

According to the present invention, in a recording device that detects the width of a recording medium using an optical sensor, it is possible to calculate a threshold value that can accurately determine the presence or absence of a recording medium regardless of the type of recording medium. can.

A schematic cross-sectional view showing the configuration of a recording device Schematic diagram showing the configuration of the carriage and optical sensor Diagram showing the configuration of the control block of the recording device Flowchart showing the recording medium width determination sequence of Example 1 Schematic diagram regarding the recording medium width detection method of Example 1 Continuation of schematic diagram regarding recording medium width detection method of Example 1 Continuation of schematic diagram regarding recording medium width detection method of Example 1 Diagram showing the configuration related to output adjustment Flowchart showing recording medium width determination sequence of Example 2 Flowchart showing the recording medium width determination sequence of Example 3 Flowchart showing the operation of the conventional example Schematic diagram of a conventional recording medium width detection method Continuation of the schematic diagram of the conventional recording medium width detection method

Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following examples should be changed as appropriate depending on the configuration and various conditions of the device to which the present invention is applied. Therefore, unless there is a specific description, it is not intended to limit the scope of the present invention.

[Example 1]
In the following embodiments, the recording medium to be recorded (printed) may be a sheet-like member that can be printed by a recording device. For example, it can include various sheet-like members such as various papers and resin sheets (typically transparent sheets such as clear films). In the following description, even if the recording medium is referred to as "paper" or the "recording medium width" is referred to as "paper width," this is not intended to limit the type of recording medium.

(Device configuration)
FIG. 1 is a sectional view showing a schematic configuration of a recording apparatus 100. A recording medium 104 (for example, printing paper) is stored in the paper feed tray 101 . Paper feed roller 103 feeds printing paper stored in paper feed tray 101 to transport rollers 105 and 106 . The recording medium 104 is sent to a transport path formed by members 107 and 108 by transport rollers 105 and 106, and is transported to transport rollers 109 and 110. Conveyance rollers 109 and 110 convey the recording medium 104 to a platen 111 serving as a conveyance section. The transport unit is a member that constitutes a path for the recording medium 104, and can support the recording medium 104 during transport. The recording medium 104 is conveyed on the conveyance section by the operation of the conveyance roller.

A carriage 113 on which a print head 112 is mounted is provided above the platen 111. The carriage 113 reciprocates along the guide rail 114 in the A direction (direction from the front to the back in the drawing) and the B direction (direction from the back to the front) shown in FIG. The A direction and the B direction are directions that intersect (typically orthogonal to) the transport direction of the recording medium 104, and are also referred to as the width direction. The control unit 308 causes the print head 112 to eject recording material such as ink by applying a drive pulse to the print head 112 while causing the carriage 113 to scan in the A direction and the B direction. By ejecting the recording agent onto the recording medium 104 while the print head 112 scans in this manner, an image to be printed is printed on the recording medium 104. The recording medium 104 on which the image has been printed is further conveyed to discharge rollers 115 and 116 by conveyance rollers 109 and 110. Paper discharge rollers 115 and 116 discharge the recording medium 104 to a paper discharge tray 117.

Further, the carriage 113 is provided with a paper sensor 118 that is a reflective optical sensor. The recording device 100 obtains the output level (output voltage) indicating the intensity of light received by the paper sensor 118, and determines whether the output level corresponds to the reflected light from the recording medium. , it is possible to detect whether a recording medium exists at the position where the light is received. Also, as described above, the paper sensor 118 is provided on the carriage 113 and is scanned together with the print head 112. The recording apparatus 100 can determine the edge of the printing paper in the scanning range by detecting whether the recording medium 104 is present in the scanning range of the paper sensor 118. Then, the width of the printing paper can be detected based on the distance between the left and right edges of the printing paper.

(Configuration for detection)
The details of the detection process by the paper sensor 118 will be explained using FIG. 2. The scanning position of the paper sensor 118 (carriage 113) is detected by an encoder 224, which will be described later.

The recording apparatus 100 prints an image on a recording medium 104 by discharging a recording material from a print head 112 while moving a carriage 113 back and forth along a guide rail 114 in the directions of arrows A and B. Further, a head recovery mechanism 119 is provided at a position away from the platen 111 in the moving range of the carriage 113 (position x of the paper sensor) in order to cap the print head 112. The position x of the paper sensor is specified by the position of the carriage 113 detected by an encoder 224, which will be described later.

The paper sensor 118 irradiates light while scanning the platen 111 and receives reflected light. The graph shown at the bottom of FIG. 2 shows changes in the output level of light detected by the paper sensor 118 within the movement range of the carriage 113. In this example, the recording medium 104 is a bright color such as white, and the platen 111 is a dark color such as black. Therefore, a high output level (strong reflected light from the printing paper) is obtained for the position where the recording medium 104 is present on the platen 111, and a low output level (weak reflected light from the platen 111) is obtained for the position where the recording medium 104 is not present. reflected light) is detected.

Paper sensor 118 receives reflected light at position E on platen 111 when carriage 113 is at the position of head recovery mechanism 119 . Then, when the carriage 113 moves in the direction A, the output level increases at a position corresponding to the end of the recording medium 104. A roughly constant output level is obtained from one end of the recording medium 104 to the opposite end, and the output level decreases at the end.

In this embodiment, when the output level of the paper sensor 118 exceeds a predetermined threshold value Vth, it is determined that the recording medium 104 is present at the position where the output level is detected. Specifically, positions G and F in FIG. 2 are the end positions of the recording medium 104, and the range from position G to position F is the range in which the recording medium 104 exists. Then, the distance from position G to position F is detected as the paper width in the direction orthogonal to the conveyance direction of the recording medium 104.

Note that in this embodiment, the recording apparatus 100 transports the recording medium 104 in a centered manner so that the center of the recording medium 104 is at the center position C of the platen 111. At this time, if the recording medium 104 is large and the right end of the recording medium 104 is on the right side of position E in FIG. 2, the position of the right end of the recording medium 104 may not be detected.

Therefore, in this embodiment, when the right end position of the recording medium 104 is to the right of the position E, the recording apparatus 100 adjusts the distance between the center position C and the left end position G of the recording medium 104. Determine the paper width. Specifically, first, when the output level at position E exceeds Vth, it is determined that the right end position of the recording medium 104 is at position E or to the right of position E. When it is determined in this way, the length obtained by doubling the distance between the center position C and the position G is detected as the paper width of the recording medium 104. This is because, as described above, the recording device 100 transports the recording medium 104 so that the center of the recording medium 104 is at the center position C, so the center position C and the left end position G of the recording medium 104 are This is because the distance is half the paper width. Note that a value indicating the center position C in the scanning range of the carriage is stored in advance in the memory within the recording device 100, and the recording device 100 calculates the distance between the center position C and the position G by referring to this value. be able to.

Note that, as described later, the threshold value Vth does not need to be a fixed value, and may be changed depending on the output level at the position E. Further, the threshold value Vth may be determined depending on the intensity of reflected light depending on the surface characteristics of the print medium. Specifically, the threshold value Vth is changed depending on the type of paper used for printing (plain paper, glossy paper, etc.).

(Block configuration)
Next, the configuration of the recording device 100 will be explained. FIG. 3 is a block diagram showing the configuration of functional blocks of the recording device 100.

The control unit 308 controls the recording device 100. As the control unit 308, it is possible to use an information processing device, a processing circuit, etc., which is equipped with arithmetic means such as a CPU and memory, and operates according to a program or a user's instructions. The memory 204 is a storage means, and any storage device such as RAM, ROM, or hard disk can be used. The user's instructions may be given as a job from an external device F such as a computer that can communicate with the recording device 100, or may be given by user input using an operation panel of the recording device 100. Further, the control unit 308 includes various control blocks described below. Each control block is, for example, a program module configured to implement a particular function.

The motor control unit 209 controls various motors for driving the printing mechanism of the recording apparatus 100 under the control of the control unit 308 . The conveyance motor 210 drives the paper feed roller 103 , the conveyance rollers 105 , 106 , 109 , and 110 , and the paper discharge rollers 115 and 116 under the control of the motor control unit 209 . The carriage motor (CR motor 211) drives the carriage 113 as a scanning unit under the control of the motor control unit 209, and causes the carriage 113 to reciprocate. The scanning section is a block that causes the sensor section to scan over a recording medium or other object to be detected. Recovery motor 212 drives head recovery mechanism 119 under the control of motor control section 209 .

The head control unit 213 controls the print head 112 as a recording unit under the control of the control unit 308, and causes the print head 112 to eject a recording agent such as ink. The recording unit is a block that performs a recording operation on a recording medium based on a recording command. The control unit 308 drives both the print head 112 and the conveyance motor 210 to print an image on the printing paper while scanning the print head 112. That is, the control unit 308 in the recording apparatus 100 operates as a print control device, controls various motors as a printing mechanism, and the print head 112, and causes the printing mechanism to print an image.

Under the control of the control unit 308, the sensor control unit 214 causes a sensor light source 215 (irradiation unit) included in the paper sensor 118 as a sensor unit to emit light, and also causes an optical sensor 216 (light reception unit) included in the paper sensor 118 to emit reflected light. to receive light. The sensor section is a block that irradiates light onto an object to be detected and detects the reflected light. The platen 111 is present in a portion facing the range scanned by the paper sensor 118. Therefore, if the recording medium 104 is present on the platen 111, the target of the irradiation light from the sensor light source 215 is the recording medium 104, and even if the recording medium 104 is not present on the platen 111, For example, the platen 111 is irradiated with the irradiation light from the sensor light source 215 .

The sensor control unit 214 also acquires an output level indicating the intensity of light received by the optical sensor 216. The control unit 308 can determine the recording medium width by acquiring the output level acquired by the sensor control unit 214. The sensor control unit 214 functions as an output adjustment unit that adjusts the amount of light emitted from the sensor light source 215 so that the intensity of the signal output from the optical sensor 216 becomes the target output based on the intensity of the received light. Be prepared.

Encoder 224 specifies the position of carriage 113 as it scans along guide rail 114. The control unit 308 specifies the paper sensor position x shown in FIG. 2 based on the position of the carriage 113 specified by the encoder 224 and the mounting position of the paper sensor 118 on the carriage 113.

In the recording apparatus 100 of this embodiment, a paper sensor 118 is provided on the carriage 113 together with the print head 112. Various motors and guide rails 114 for moving the carriage 113, encoders 224 for specifying the position of the carriage 113, and other members are used for printing by the print head 112 and detecting the recording medium width by the paper sensor 118. Commonly used for both. Therefore, it is not necessary to provide the above-mentioned member for detecting the width of the recording medium in addition to the member for printing, and it is possible to prevent the recording apparatus 100 from increasing in size.

The detection unit 305 of the control unit 308 is a block that detects the width of the recording medium based on the comparison result between the output from the sensor unit and a threshold value. The threshold value setting unit 306 is a block that receives the output of the sensor unit and sets an optimal threshold value for detection.

(Problems with conventional example)
The inventor conducted a study on problems in conventional recording devices. In the conventional recording medium width detection method, if the recording medium has a high reflectance to the light from the optical sensor, the difference between the output obtained from the recording medium and the output obtained from the part without the recording medium is sufficient. Therefore, it is possible to detect the paper width by calculating a threshold value from the peak of each distribution. However, in the case of a recording medium such as tracing paper or clear film, which has a low reflectance to light from an optical sensor, the output that can be obtained will vary between the area where the recording medium is and the area where there is no recording medium. The difference becomes small. As a result, there is a possibility that the presence or absence of the recording medium may be erroneously detected, and the width of the recording medium may be erroneously detected.

The above study will be described in detail with reference to FIGS. 12 and 13. FIG. 12 shows how similar threshold calculations were performed for a recording medium 104a with a high reflectance, and FIG. 13 a recording medium 104b with a low reflectance. In each figure, the top row (a) shows the state in which the recording medium 104 is conveyed onto the platen 111 by the conveyance roller 110. The platen 111 is provided with ribs (low) 111a, which are ribs with a low height from the transport surface, and ribs (high) 111b, which are ribs with a high height from the transport surface, along the transport direction. . Further, the second row (b) from the top of each figure shows a cross-sectional view in a plane perpendicular to the conveyance direction. Paper width detection is performed by scanning the paper sensor 118 in the direction of the arrow when the recording medium 104 is at the detection position.

In addition, in the third row (c) from the top of each figure, the horizontal axis represents the position within the scanning range of the carriage 113, and the vertical axis represents the intensity of the signal output from the optical sensor 216 of the paper sensor 118 (output Vout). This is a graph showing. The position on the horizontal axis corresponds to the position on the platen 111 shown in the horizontal direction of the uppermost stage and the second stage. For example, in FIG. 12, the output Vout has the highest value (908) when scanning the recording medium 104a with high reflectance (910). The output Vout becomes lower in the following order: when scanning over the rib (high) 111b, when scanning over the rib (low) 111a, and when scanning a portion of the platen 111 without ribs.

The bottom row (d) of each figure is a graph in which the horizontal axis represents the value of the output Vout and the vertical axis represents the number of appearances. The number of appearances refers to the number of signals when the signals output by the optical sensor 216 during scanning are digitally converted at a predetermined sampling rate. At this time, a peak 911 (paper white output V _WHITE ) corresponding to the output Vout at the position where the recording medium 104a exists, and a peak 911 (paper white output V WHITE ) corresponding to the output Vout at the position where the recording medium 104a does not exist (the non-ribbed portion of the platen 111). A peak 910 (platen output V _DARK ) is present. In FIG. 12(d), there are also two small peaks corresponding to the rib (low) 111a and the rib (high) 111b, respectively.

In the conventional recording apparatus, the threshold value V _TH was calculated by calculating the average value of two peaks as shown in equation (1) below. The threshold value V _TH is indicated by reference numeral 909 in (c) and (d).
V _TH = (V _WHITE + V _DARK )/2...(1)

In the case of FIG. 12, the presence or absence of paper could be accurately determined using the threshold value _VTH calculated as described above. On the other hand, the situation in FIG. 13 is different. That is, when the optical sensor performs the same operation on the recording medium 104b, the output Vout in the portion where the recording medium 104b exists becomes a low value as shown by reference numeral 914 in FIG. 13(c). Therefore, when the number of appearances for each output Vout is graphed, as shown in FIG. 13(d), the peak of the paper white output V _WHITE (code 918) and the peak of the platen output V _DARK (code 917) are close to each other. Therefore, as shown in FIG. 13(c), the threshold value V _TH (symbol 913) calculated by equation (1) has a value comparable to the output Vout at the position of the rib (low) 111a. As a result, although the original width of the recording medium is the width shown by 915, it is mistakenly detected as the width shown by 916. Therefore, the inventor devised a method of appropriately setting a threshold value regardless of the type of recording medium to improve the accuracy of recording medium width detection.

(Processing sequence)
FIG. 4 is a flowchart showing the processing sequence for determining the recording medium width in this embodiment. A recording medium width detection sequence is started in step S400. In the first recording medium passing operation in step S401, the recording medium 104 is conveyed directly below the paper sensor 118 by the conveying roller group. The first recording medium paper passing operation is paper passing for preliminary detection performed prior to actual width detection.

In step S402, the output Vout is measured with the paper sensor 118 facing the recording medium 104. At this time, the paper sensor 118 is placed facing a location where the recording medium 104 is known to be present. Specifically, in the conveyance direction, the position of the leading end of the recording medium 104 can be determined based on the size of the recording medium 104 and the amount of feed by the conveyance roller. In addition, in the direction perpendicular to the conveyance direction, since the range of paper width that can be printed by the recording device 100 is known, by moving the carriage 113 within a predetermined range from the reference position, the paper sensor 118 is moved toward the recording medium. 104. The reference position is, for example, the center of the paper passing path or the end abutting portion of the paper passing path. In such a facing state, the sensor control unit 214 causes the sensor light source 215 to emit light with a predetermined amount of light, and measures the output Vout of the optical sensor 216.

In step S403, the control unit 308 compares the output Vout with a predetermined target output value. The target output here is the maximum value (saturation value) of the output Vout, which is determined by the specifications of the optical sensor 216. Note that in order to avoid causing errors, a value slightly lower than the saturation value (for example, a value 5% lower than the saturation value) may be set as the target output. If the output Vout does not reach the target output, the process advances to step S404, and the control unit 308 increases the light amount of the sensor light source 215 and continues output measurement. Then, when the output Vout reaches the target output, the control unit 308 stores in the memory 204 the amount of light when the target is reached in step S405. S402 to S405 are output adjustment steps in which the sensor output is adjusted to the target output.

In step S406, the control unit 308 temporarily retreats the recording medium 104 from the reading range of the paper sensor 118. In step S407, a black output detection step is performed. Specifically, the control unit 308 measures the output by the paper sensor 118 while scanning the carriage 113, and obtains the detection result in a state where the recording medium 104 is not present. Thereby, the detection result based on the reflection of the platen 111 can be recorded. In step S408, the threshold value setting unit 306 calculates the threshold value _VTH using the target output and the measurement results in the black output detection step. This process will be described later.

In step S409, a second recording medium passing operation is performed. The second recording medium paper passing operation is paper passing for actual paper width detection. Here, the recording medium 104 is again transported directly below the paper sensor 118 by the transport roller group. In the process of reading the recording medium width in step S410, the control unit 308 causes the sensor light source 215 to emit light according to the amount of light stored in the memory in S405 while scanning the carriage 113, and measures the output Vout of the optical sensor 216. In step S411, the detection unit 305 detects the edge of the recording medium 104 based on the reading result in S410 and the threshold value _VTH calculated in S408, and calculates the paper width. This completes the recording medium width detection sequence (step S411).

The threshold calculation in this sequence will be described in detail using FIGS. 5 to 7. In each figure, the upper part (a) shows the state in which the recording medium 104 is conveyed onto the platen 111 by the conveyance roller 110. The middle row (b) shows a cross-sectional view taken in a plane perpendicular to the transport direction. In the lower row (c), the horizontal axis represents the position within the scanning range of the carriage 113, and the vertical axis represents the optical sensor 216 of the paper sensor 118.
It is a graph showing the strength of the signal (output Vout) output from the .

FIG. 5 is a schematic diagram of the output adjustment step (S402 to S405) of the above flow. The recording medium 104 is transported by the transport roller 110 to a reading position by a paper sensor 118 on the platen 11 . At this time, the recording medium 104 is supported by ribs (low) 111a or ribs (high) 111b, which are part of the platen 111, and maintains the posture required for printing. Further, the paper sensor 118 faces a location where the recording medium 104 is definitely present.

In the graph of FIG. 5(c), the solid line portion is the actually measured output, and the broken line portion is shown for reference. Here, it is assumed that the control unit 308 causes the sensor light source 215 to emit light with a predetermined initial light amount to obtain the first output Vout (reference numeral 509). The control unit 308 compares the first output Vout with the target output value (symbol 510), and if the first output Vout is lower than the target output, the sensor control unit 214 adjusts the output to reach the desired target output. The amount of light is increased until (V _WHITE , code 511) is obtained.

FIG. 6 is a schematic diagram of the black output detection step S406 of the above flow. The recording medium 104 is in a state of being evacuated outside the reading range of the paper sensor 118. The sensor control unit 214 causes the sensor light source 215 to emit light using the light amount (adjusted light amount) stored in the memory in S405, and measures the output. At this time, the paper sensor 118 performs measurement while the carriage 113 scans the range indicated by the arrow 507. As a result, the reflected light from the platen 111, the ribs (low) 111a, the ribs (high) 111b, etc. on the platen is read, and the output Vout (reference 512) at the time of black detection is output derived from the platen reflection. is obtained (transport unit output). The threshold value setting unit 306 stores the maximum value among these outputs in the memory as V _DARK (code 513).

FIG. 7 is a schematic diagram of the recording medium width reading step and calculation step (S410 to S411) in the above flow. The recording medium 104 has been conveyed to the reading range again. The control unit 308 performs output measurement using the light amount stored in S405 while scanning the paper sensor 118 in the range indicated by the arrow 507. As a result, an output Vout (reference numeral 514) at the time of paper width detection is obtained. At this time, the output Vout at the position where the recording medium 104 exists is the target output (V _WHITE 511).

The threshold value setting unit 308 calculates the threshold value V _TH based on the V _WHITE 511 and the V _DARK 513 . For example, calculation is performed using the following equation (2), which is similar to equation (1) (reference numeral 515).
V _TH = (V _WHITE + V _DARK )/2...(2)
Note that the method for calculating the threshold value from V _WHITE 511 and V _DARK 513 is not limited to obtaining an average value, but can be determined as an intermediate value between V _WHITE 511 and V _DARK 513.

Then, the detection unit 305 calculates the recording medium width 516 by comparing Vout 514 and the threshold value V _TH 515. In this way, by calculating the threshold value V _TH 515 from the V _WHITE 511 obtained in the output adjustment step and the V _DARK 513 obtained in the black output detection step, the height of the rib (height) 111b is calculated in the detection of the recording medium width. The influence of the width 517 can be reduced.

FIG. 8 is a schematic diagram of a configuration example related to the output adjustment process. The paper sensor 118 in this example includes a sensor light source 215 that is an LED light source, and an optical sensor 216 that is a photoelectric conversion unit. The control unit 308 includes a sensor control unit 214 that is a current control circuit. The sensor light source 215 emits irradiation light 604 when supplied with a controlled current from the sensor control unit 214 . The optical sensor 216 receives reflected light 606 obtained by reflecting the irradiated light 604 by the recording medium 104 and photoelectrically converts the received reflected light 606 to obtain an output Vout (reference numeral 607). The control unit 308 controls the sensor control unit 214 so that the output Vout becomes a desired output.

As described above, in this embodiment, first, the output of the recording medium is adjusted, and the control value of the light source is determined so that the amount of light corresponding to the target output can be obtained. Then, using the amount of light, a black detection step is performed in a state where there is no recording medium. Then, a threshold value is determined based on the output during black detection and the target output. Then, the result of scanning the recording medium using the stored light source control value is compared with a threshold value to determine the width of the recording medium. By doing this, even if the reflectance varies depending on the type of recording medium, the influence of variations in optical sensor output can be reduced. In particular, even in cases where the resolution of determination using a threshold value is reduced in conventional methods due to the low reflectance of the recording medium, it is possible to raise the output level of the optical sensor to the maximum value (or near the maximum value). Accordingly, it is possible to expand the dynamic range and calculate a threshold value with high resolution. Therefore, it is possible to set an appropriate threshold value for detecting the presence or absence of a recording medium. As a result, the width of the recording medium can be accurately detected, and printing outside the paper surface can be prevented.

[Example 2]
FIG. 9 is a flowchart illustrating the processing of the second embodiment. Hereinafter, the explanation will focus on the parts that are different from the first embodiment, and the same parts will be given the same step numbers and symbols, and the explanation will be omitted.

In the first embodiment, regardless of the type of recording medium 104, the output adjustment step (S402 to S405) to the threshold value calculation step (S408) are performed. However, in the case of a general recording medium 104, the width of the recording medium can be accurately detected even by using predetermined driving conditions and light intensity of an optical sensor or a threshold value for paper width detection. Therefore, if the flow of the first embodiment is applied to all recording media 104, extra time will be consumed. Therefore, in the second embodiment, the type of recording medium is determined in advance based on user input.

The premise for starting the sequence is that the control unit 308 recognizes the type information of the recording medium 104 to be printed. The type information here means that the recording medium 104 has a normal reflectance to which predetermined optical sensor driving conditions and thresholds can be applied, or has a reflectance so low that it is necessary to calculate a special threshold. This is information indicating whether the A typical example of the former is common white printing paper, while a typical example of the latter is tracing paper or clear film. As such type information, information included in a job from the external device F or information input by the user from the panel of the recording device 100 can be used.

A recording medium width detection sequence is started in step S700. In step S701, the control unit 308 determines whether the recording medium 104 requires output adjustment. If output adjustment is necessary (S701=Yes), the same processing as in the first embodiment (steps S401 to S408) is performed to calculate the threshold value V _TH . On the other hand, if output adjustment is not necessary (S701=No), the process from S409 onwards is performed using the preset optical sensor driving method and threshold value.

In this embodiment, the type information of the recording medium specified by the user at the start of printing is used to determine whether to perform the output adjustment step. Therefore, since the output adjustment process is not performed if it is not necessary, the operation time can be shortened.

[Example 3]
FIG. 10 is a flowchart illustrating the processing of this embodiment. Hereinafter, the explanation will focus on the parts that are different from the first embodiment, and the same parts will be given the same step numbers and symbols, and the explanation will be omitted.

In the first embodiment, the threshold value calculation step (S408) is performed from the output adjustment step (S402 to S405) regardless of the type of recording medium. However, in the case of a general recording medium 104, the width of the recording medium can be accurately detected even by using predetermined driving conditions and light intensity of an optical sensor or a threshold value for paper width detection. Therefore, if the flow of the first embodiment is applied to all recording media 104, extra time will be consumed. On the other hand, in the second embodiment, the type of recording medium is determined in advance based on the user's input. However, due to input errors by the user or variations between individual recording media 104, the expected output may not be obtained. Therefore, in the third embodiment, the optical sensor output is compared with a preset threshold value when paper is passed.

A recording medium width detection sequence is started in step S800. Steps S401 and S402 are the same processes as in the first embodiment. In step S801, the control unit 308 compares the sensor output Vout obtained by light irradiation with a predetermined initial light amount in S402 with a predetermined second threshold value. If the output is equal to or less than the second threshold (S801=Yes), it is determined that the current recording medium 104 is a special paper such as tracing paper or clear film, and the light intensity is increased in step S802. Thereafter, the process proceeds to step S403 and subsequent steps similar to those in the first embodiment. On the other hand, if the output is larger than the second threshold (S801=No)
The control unit 308 determines that the recording medium 104 has a sufficiently high reflectance, and proceeds with the processing from S409 onwards using the preset optical sensor driving method and threshold value. The second threshold value is determined based on the results of reflectance measurements of various types of recording media 104 in advance, and is determined between the output based on the reflectance of general paper such as copy paper and the output based on the reflectance of special paper. It is preferable that the value be set to the value.

In this embodiment, it is determined whether to perform the output adjustment process depending on the output of the sensor unit when paper is passed. As a result, the influence of input errors by the user and individual variations in the recording medium can be reduced, and the width of the recording medium can be accurately detected.

[Configuration 1]
a recording unit that records on a recording medium;
a conveyance unit that supports the recording medium being conveyed;
a sensor unit including an irradiation unit that irradiates irradiation light; and a light reception unit that receives reflected light and outputs a signal according to the intensity of the reflected light;
a scanning unit that scans the sensor unit in a width direction that intersects with a conveyance direction by the conveyance unit;
a control unit that detects the width of the recording medium by comparing the output from the light receiving unit with a threshold value to detect the presence or absence of the recording medium;
A recording device comprising:
The control unit includes:
By irradiating the recording medium from the irradiation unit while adjusting the intensity of the irradiation light, an adjusted light intensity is obtained such that the output from the light receiving unit becomes a target output,
By irradiating the irradiation light using the adjusted light amount in a state where the recording medium is not present in a range facing the sensor unit to be scanned, the light receiving unit can detect light from the light receiving unit based on the reflected light from the transport unit. Obtaining the transport unit output which is the output,
A recording apparatus characterized in that the threshold value for detecting the presence or absence of the recording medium is determined based on the target output and the output of the conveying section.
[Configuration 2]
Configuration 1, wherein the control unit sets the threshold value to an intermediate value between the maximum value of the outputs of the transport unit outputted by the light receiving unit while the sensor unit is scanned, and the target output. Recording device described in .
[Configuration 3]
3. The recording apparatus according to configuration 1 or 2, wherein the target output is set based on a value of the output when the output from the light receiving section is saturated.
[Configuration 4]
The recording apparatus according to configuration 3, wherein the target output is set to a value lower than a value of the output when the output from the light receiving section is saturated.
[Configuration 5]
Any one of configurations 1 to 4, wherein the control unit determines whether to acquire the adjusted light amount and the output of the conveyance unit, depending on type information of the recording medium. The recording device according to item 1.
[Configuration 6]
The recording device according to configuration 5, wherein the control unit acquires the type information of the recording medium from a user.
[Configuration 7]
If the output when the recording medium is irradiated with the irradiation light with a predetermined initial light intensity is equal to or less than a second threshold, the control unit acquires the adjusted light intensity and obtains the transport unit output. 5. The recording device according to any one of configurations 1 to 4, wherein the recording device performs the following steps.

100: Recording device, 104: Recording medium, 111: Platen, 112: Print head, 113: Carriage, 118: Paper sensor, 215: Sensor light source, 216: Optical sensor, 308: Control unit

Claims (7)

a recording unit that records on a recording medium;
a conveyance unit that supports the recording medium being conveyed;
a sensor unit including an irradiation unit that irradiates irradiation light; and a light reception unit that receives reflected light and outputs a signal according to the intensity of the reflected light;
a scanning unit that scans the sensor unit in a width direction that intersects with a conveyance direction by the conveyance unit;
a control unit that detects the width of the recording medium by comparing the output from the light receiving unit with a threshold value to detect the presence or absence of the recording medium;
A recording device comprising:
The control unit includes:
By irradiating the recording medium from the irradiation unit while adjusting the intensity of the irradiation light, an adjusted light intensity is obtained such that the output from the light receiving unit becomes a target output,
By irradiating the irradiation light using the adjusted light amount in a state where the recording medium is not present in a range facing the sensor unit to be scanned, the light receiving unit can detect light from the light receiving unit based on the reflected light from the transport unit. Obtaining the transport unit output which is the output,
A recording apparatus characterized in that the threshold value for detecting the presence or absence of the recording medium is determined based on the target output and the output of the conveying section. The control unit sets the threshold value to a value intermediate between the maximum value of the outputs of the transport unit outputted by the light receiving unit while the sensor unit is scanned, and the target output. 1. The recording device according to 1. The recording apparatus according to claim 1, wherein the target output is set based on a value of the output when the output from the light receiving section is saturated. 4. The recording apparatus according to claim 3, wherein the target output is set to a value lower than a value of the output when the output from the light receiving section is saturated. 5. The control unit determines whether to acquire the adjusted light amount and the output of the transport unit according to type information of the recording medium. The recording device according to item 1. The recording apparatus according to claim 5, wherein the control unit acquires the type information of the recording medium from a user. If the output when the recording medium is irradiated with the irradiation light with a predetermined initial light intensity is equal to or less than a second threshold, the control unit acquires the adjusted light intensity and obtains the transport unit output. 5. The recording apparatus according to claim 1, wherein the recording apparatus performs the following.

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