JP6152284B2 - Recording device - Google Patents

Description

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

  Conventionally, as a recording apparatus, a recording sheet as a recording medium is intermittently sent in a recording sheet conveyance direction (sub-scanning direction), and an ink jet recording head is crossed in the recording sheet conveyance direction (main scanning). 2. Related Art Inkjet printers that perform printing while scanning in the 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 equipped.

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 the edge of a recording sheet is AC-coupled so as to enable edge detection even during printing, and a differential waveform is amplified by an operational amplifier. Proposals have been made to detect the differential waveform with a comparator after filtering.

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, there is sensitivity variation in the sensor itself. If the light emission current and light reception sensitivity of the sensor are made variable in order to suppress this variation, 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. In some cases, every point on the paper is detected as an edge, and an appropriate edge position cannot be detected.

  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.

A recording apparatus according to the present invention includes a recording head that ejects ink onto a recording medium, a conveying unit that conveys the recording medium, and a carriage that carries the recording head and reciprocates in a direction that intersects the conveying direction of the recording medium. A first level signal is output when the recording medium is mounted on the carriage and the detection area is present, and a second level signal different from the first level is output when the recording medium is not present in the detection area. An edge sensor that outputs the scale, a scale arranged along the moving direction of the carriage, a scale sensor that detects the scale of the scale, a counter that counts values based on the detection result of the scale sensor, and the sensor A memory for acquiring the value of the counter when the level of the output signal changes, and the recording medium is conveyed by a predetermined amount by the conveying means The calculation means for acquiring the count value acquired in the memory and calculating the displacement amount of the recording medium in the direction intersecting the transport direction, and the displacement amount calculated by the calculation means are predetermined. if it exceeds the range, have a, and a control means for performing control to stop recording onto the recording medium by the recording head, the amount of displacement, by ejecting ink from the recording head on the recording medium image Before recording, the edge of the recording medium is detected by the edge sensor, and the detected edge position of the recording medium is then detected based on the detected edge position of the recording medium. A first displacement amount, and a second displacement amount based on the position of the edge of the recording medium detected by the edge sensor before and after the recording medium is conveyed by the predetermined amount. The determined range includes a first allowable amount within the range and a second allowable amount smaller than the first allowable amount, and the control means calculates the calculated first displacement amount and the second displacement amount. When comparing the first allowable amount and the second allowable amount, respectively, when the first displacement amount exceeds the first allowable amount or when the second displacement amount exceeds the second allowable amount, Control is performed to stop recording on the recording medium by the recording head, and the first displacement amount is equal to or less than the first allowable amount, and the second displacement amount is equal to or less than the second allowable amount. The recording head is controlled to continue recording on the recording medium .

  According to the present invention, the presence / absence of the recording medium is calculated based on the level of the signal output from the sensor, and the edge is detected. Therefore, even if the speed at which the sensor crosses the edge of the recording medium increases, it can be accurately detected. Further, by detecting the edge of the recording medium even during printing, a recording error due to meandering of the recording medium can be prevented, and printing can be accurately performed at a predetermined position on the recording medium. The

FIG. 1 is a block diagram showing the main configuration of the recording apparatus. FIG. 2 is a diagram illustrating an example of the configuration of the recording apparatus. FIG. 3 is a diagram illustrating an example of a recording medium to be conveyed. FIG. 4 is a flowchart for explaining the operation.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing the main configuration of the recording apparatus.
The control unit 1 is a control unit that operates according to a program stored in advance and performs various controls of the entire apparatus. The ROM 2 is a non-volatile memory and stores information such as a program of the control means 1 and initial setting values. A RAM 3 is a work memory used for calculation by the control means 1 and a memory for temporary storage.

  The conveyance motor 5 is a motor that drives a conveyance unit including a roller that conveys a recording medium such as recording paper or a plastic film. The transport motor 5 operates based on a drive signal from the motor driver 4, and the motor driver 4 operates according to a control signal from the control means 1.

  The carriage motor 7 is a motor that mounts a recording head 11 that ejects ink and drives a carriage that reciprocates in the width direction of the recording medium. The carriage motor 7 operates based on a drive signal from the motor driver 6, and the motor driver 6 operates according to a control signal from the control means 1.

  The edge sensor 9 is a sensor that is mounted on the carriage and detects a recording medium from the moving carriage. The presence or absence of the recording medium is detected by the intensity of the light that is emitted and rebounds. The edge sensor 9 operates based on the drive signal from the sensor driver 8 and outputs the detected analog signal to the sensor driver 8. The sensor driver 8 performs AD conversion on the analog signal, digitizes it, and outputs it to the control means 1. The sensor driver 8 is operated by a control signal from the control means 1.

  The recording head 11 performs an ink ejection operation on the head drive circuit 10 based on the drive signal. The head drive circuit 10 operates based on a control signal from the control means 1.

  The linear sensor 13 is a sensor that optically detects a scale of a linear scale arranged linearly along the moving direction of the carriage. The sensor driver 12 operates based on a control signal from the control means 1. The linear sensor 13 operates according to a drive signal from the sensor driver 12 and outputs a detection result to the sensor driver 12. The sensor driver 12 AD-converts the input detection result and outputs it to the control means 1.

  The counter circuit 14 is controlled by the control means 1. Counting is performed based on the value detected by the linear sensor 13. The position of the carriage can be specified by this count value.

  The trigger circuit 15 is controlled by the control means 1. The trigger circuit 15 operates based on the detection result of the edge sensor 9. The counter memory 16 is a memory that stores the value counted by the counter circuit 14 in accordance with an instruction from the trigger circuit 15. That is, when the edge of the recording medium is detected by the edge sensor 9, the trigger circuit 15 is operated, and the count value of the counter circuit 14 at that time is stored in the counter memory 16. The count value stored in the counter memory 16 is a value when the edge of the recording medium is detected by the edge sensor 9, and is acquired by the control means 1 and used for various calculations. The trigger circuit 15, the counter circuit 14, and the counter memory 16 can acquire the correct carriage position even when the carriage is moving during printing or the like. Therefore, it becomes easy to find abnormal conveyance of the recording medium during printing, and a major problem such as jam can be avoided.

FIG. 2 is a diagram illustrating an example of the configuration of the recording apparatus.
The recording device 20 is an ink jet printer. The pulleys 21 are disposed at substantially both ends of the recording apparatus, and an endless belt 24 is wound around the two pulleys. A carriage 22 is fixed to the endless belt 24. By moving the endless belt 24, the carriage 22 moves in conjunction with it. A carriage motor 7 is connected to one of the pulleys 21, and the endless belt 24 is rotated by driving the carriage motor 7. The recording head 11 is mounted on the carriage 22. In order to perform color printing, four recording heads 11 are mounted corresponding to four colors of black, cyan, magenta, and yellow. It can also be multicolored.

  One carriage 23 indicated by a dotted line indicates one folding position of the reciprocating movement. The other carriage 29 indicated by a dotted line indicates the other folding position of the reciprocating movement. A cap 35 is disposed immediately below the other folding position. The cap 35 is in close contact with the nozzle surface of the recording head 11 so as to surround the nozzle, can prevent the ink from drying, and can suck ink from the recording head 11 by applying a negative pressure. .

  The linear scale 25 is a linear scale disposed along the moving direction of the carriage 22. The linear scale 25 is read by the linear sensor 13.

  The recording medium 28 is recording paper, a plastic film, or the like, and an image is recorded by ink ejected from the recording head 11. The recording medium 28 is conveyed in the depth direction of the drawing by conveying rollers 27 arranged in the width direction of the recording medium 28. The platen 26 is a flat plate arranged to face the moving recording head 11. The platen 26 is provided with a suction hole, and is fixed so as not to be displaced during recording by sucking the recording medium 28. A conveyance roller 27 is disposed on the back side of the platen 26, that is, on the upstream side in the conveyance direction of the recording medium 28.

  The edge detection signal 34 indicates a detection signal of the recording medium 28 detected by the edge sensor 9. That is, when the carriage 22 reciprocates and the edge sensor 9 moves to the position 31, the edge detection signal 34 is switched. When the edge sensor 9 moves to the position 32, the edge detection signal 34 is switched. The edge detection signal 34 is turned on while the recording medium 28 is detected, and turned off when the recording medium 28 is not detected.

  The line 35 indicating the carriage speed is zero at the return position of the carriage 22. In the figure, acceleration is performed from the position of the carriage 23 indicated by the dotted line until reaching the position 30, and the section in which the carriage 26 is disposed moves at a constant speed. The position 33 is the end of the platen 26, decelerates from here, and at the position of the cap 35, the speed becomes zero and turns. A section in which the recording medium 28 is detected is a section where the platen 26 is located, in which the carriage 22 moves at a constant speed. By making the speed of the carriage 22 constant, the detection error can be reduced by making the detection conditions constant.

FIG. 3 is a diagram illustrating an example of a recording medium to be conveyed.
The conveyance direction of the recording medium 28 is indicated by an arrow 40. It was detected by the first detection that the positions 41 and 43 are edges of the recording medium 28. The positions 42 and 44 are allowable limit positions when the recording medium 28 meanders in the right direction on the paper surface. Although the left side of the page is not shown, there is an allowable range as in the right side. This tolerance is within the second and third detections. However, in the fourth detection, it is out of the allowable range. If it is outside this allowable range, printing is stopped. Processing for abnormal conveyance of the recording medium 28 is performed.

The condition that allows the recording to be continued is that the difference between the allowable range from the first detection position and the detection result within a predetermined number of times, for example, within 5 times from the latest detection result, is within the predetermined range.
That is, the condition for continuation of printing is that the deviation amount is within a predetermined range every time a predetermined distance is conveyed.

  The reason why the deviation amount within a predetermined number of times from the latest detection result is used as a condition is to prevent a jam or the like or an abnormal winding caused by a sudden deviation in conveyance. The permissible range from the first detection position is prevented from gradually shifting and printing out of the paper or abnormal winding of the recording medium. Since the edge of the recording medium can be detected even during printing, whether it is within a predetermined range periodically or every time a predetermined distance is conveyed, whether abnormal conveyance is foreseen and whether printing should continue It can be determined whether or not.

FIG. 4 is a flowchart for explaining the operation. The operation is controlled by the control means 1 and the operation will be described.
In step S1, edge detection is performed. The carriage 22 is scanned to detect the end of the recording medium 28. The control means 1 temporarily acquires the positions at both ends from the counter memory 16 for the count value at the position 31 and the count value at the position 32.

  The recording device 20 records an image by repeating conveyance and scanning. The detection timing of the recording medium 28 may be at every scanning or scanning immediately after the recording medium 28 is transported, for example, every 3 scans or every 3 transports. It may be done periodically after being broken. Further, instead of the number of scans, it may be performed in units of time such as every minute.

  Next, in step S2, it is determined whether the detection is the first time or the second time or later. This is determined by the control means 1. If it is the first time, the process proceeds to step S3, and if it is the second time, the process proceeds to step S5.

  In step S3, the count value is stored in the RAM 3 corresponding to the detection order in order from the first detection. In step S3, the initial position is stored. This position serves as a reference, and various processes are performed according to the subsequent detected positions.

In step S4, the carriage 22 is scanned to eject ink from the recording head 11 onto the recording medium 28, and an image is recorded.
In step S5, the count value is stored in the RAM 3 corresponding to the detection order in order from the first detection. The position of the edge of the recording medium acquired according to the detection order is stored.
In step S6, how much the latest detection position is displaced from the initial detection position is calculated. The calculated displacement is temporarily stored.

  In step S7, how much the latest detection position is displaced from the previous detection position is calculated. The calculated displacement is temporarily stored. This calculation is for comparing whether the amount of displacement of the detection result within the predetermined number of times from the latest detection result is within a predetermined allowable range. It is an example. For example, the predetermined number of times may be two or more times. It is determined whether or not the conveyance is bent sharply using the calculation result.

  In step S8, the allowable range value stored in the ROM 2 is compared with the values calculated in steps S6 and S7. If the result of the comparison is within the allowable range, the process proceeds to step S4, and if it is out of the range, the process proceeds to step S9.

  In step S9, the recording process is stopped so that no further printing is performed, and this process is terminated. This is because recording on the recording medium may be stopped because there is a possibility that the recording medium cannot be correctly recorded by detecting the conveyance deviation of the recording medium exceeding the allowable range.

  Further, without stopping printing immediately, a display for selecting whether or not to continue printing may be displayed on the operation panel, and the process may be determined by user input. This allows the user to decide whether or not to continue printing, even if a displacement exceeding the allowable range is detected, if there is little remaining printing, it may be possible to print to the end. . In this case, before the process of step S9, an indication as to whether or not to continue the process is displayed on a display means (not shown), and an input to execute or stop printing from an input means (not shown) is made. Then, according to the input, the control unit 1 shifts the process to step S4 when executing printing, and to step S9 when stopping printing.

  For example, as an idea of the allowable range, the allowable amount of displacement from the first time is 1 cm, and the allowable amount of displacement from the previous time is 5 mm. If the displacement gradually changes not exceeding 5 mm, printing does not end immediately, but if there is a large change exceeding 5 mm compared to the previous time, it is considered that some problem has occurred. Therefore, a process for stopping printing is performed. If small changes continue, the meandering may be corrected, so printing is continued if it is within an acceptable range. That is, the stop condition is that there is an abrupt change that is more than half of the allowable value in the case of a gradual change.

  Even during printing in which ink is ejected from the recording head 11, the recording medium 28 can be detected using the edge sensor 9 mounted on the same carriage 22, and abnormal conveyance such as meandering of the recording medium 28 can be monitored. Printing can be stopped immediately when the allowable range is exceeded, and major problems such as jams can be prevented.

  The present invention can be used in an ink jet printer that records an image on a large format recording medium.

1 Control means 2 ROM
3 RAM
5 Carriage Motor 7 Carriage Motor 9 Edge Sensor 11 Recording Head 13 Linear Sensor 14 Counter Circuit 15 Trigger Circuit 16 Counter Memory 20 Recording Device 21 Pulley 22 Carriage 24 Endless Belt 25 Linear Scale 28 Recording Medium 27 Conveying Roller 26 Platen 35 Cap

Claims (3)

A recording head for ejecting ink onto a recording medium;
Conveying means for conveying the recording medium;
A carriage mounted with the recording head and reciprocating in a direction crossing the conveying direction of the recording medium;
A first level signal is output when the recording medium is mounted on the carriage and the detection area is present, and a second level signal different from the first level is output when the recording medium is not present in the detection area. An edge sensor to
A scale disposed along the moving direction of the carriage;
A scale sensor for detecting a scale of the scale;
A counter that counts values based on the detection result of the scale sensor;
A memory for acquiring the value of the counter when the level of the signal output from the sensor changes;
Calculating means for obtaining a count value acquired in the memory every time the recording medium is conveyed by a predetermined amount by the conveying means, and calculating a displacement amount of the recording medium in a direction intersecting the conveying direction;
Control means for performing control to stop recording on the recording medium by the recording head when the amount of displacement calculated by the calculating means exceeds a predetermined range;
I have a,
The amount of displacement is determined by detecting the edge of the recording medium by the edge sensor before ejecting ink from the recording head onto the recording medium and detecting the position of the detected edge of the recording medium. In contrast, the first displacement amount based on the position of the edge of the recording medium detected thereafter, and the edge of the recording medium detected by the edge sensor before and after the recording medium is conveyed by the predetermined amount. A second displacement amount based on the position,
The predetermined range includes a first tolerance that is within the range and a second tolerance that is less than the first tolerance;
The control means compares the calculated first displacement amount and the second displacement amount with the first allowable amount and the second allowable amount, respectively, and the first displacement amount exceeds the first allowable amount. In this case or when the second displacement amount exceeds the second allowable amount, control is performed to stop recording on the recording medium by the recording head, and the first displacement amount is equal to or less than the first allowable amount. When the second displacement amount is less than or equal to the second allowable amount , the recording apparatus controls to continue recording on the recording medium by the recording head . The recording apparatus according to claim 1, wherein the second tolerance is characterized half der Rukoto of the first capacity.   The recording apparatus according to claim 1, wherein the displacement amount is detected every time the recording medium is conveyed.

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