JP2007015396A - Recording-paper width detecting method, inkjet recording apparatus, and recording-paper width detection control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce errors in the detection of the width of recording paper, which is caused by a deterioration in the detection sensitivity of a recording-paper detecting sensor mounted in a carriage so as to detect the main-scanning-direction paper end of the recording paper. <P>SOLUTION: When a voltage value in the case where a part to be detected is detected by the recording-paper detecting sensor 64 is higher than a predetermined voltage value, it is determined that the detection sensitivity of the sensor 64 is in a high state, and a recording-paper detection threshold is set as a high voltage value (recording-paper detection threshold S1). When the above voltage value is lower than the predetermined voltage value, it is determined that the detection sensitivity of the sensor 64 is in a low state, and the recording-paper detection threshold is set as a low voltage value (recording-paper detection threshold S3). A paper-end detection error D, caused by a detection delay of the sensor 64, can be kept constant by changing the recording-paper detection threshold in the range of S1-S3, and the error is not caused by the deterioration of the detection sensitivity of the sensor 64. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The invention of the present application is equipped with a recording head for ejecting ink on recording paper, and detects the paper width of the recording paper by means of a reflective sensor such as a photo interrupter disposed on a carriage that is pivotally supported so as to reciprocate in the main scanning direction. The present invention relates to an ink jet recording apparatus having a possible configuration.

As an ink jet recording apparatus provided with recording paper width detecting means for detecting the paper width (hereinafter simply referred to as paper width) of the recording paper in the main scanning direction in which the carriage on which the recording head is mounted reciprocates, the carriage reflects the photo interrupter and the like. When the carriage on the recording paper is reciprocated, the boundary between the recording paper and the platen is identified by the reflective sensor, and the edge of the recording paper in the main scanning direction is detected. A device that is configured to detect the width of a recording paper is known. Further, in a general ink jet recording apparatus, the recording paper comes into contact with the paper end position restricting portion in the main scanning direction formed on the reference end side, that is, the so-called zero digit side, regardless of the width of the recording paper. In this state, it is conveyed in the sub-scanning direction. Therefore, the paper end on one end side in the main scanning direction of the recording paper is always defined at the same position regardless of the paper width. Therefore, the paper end on the other end side of the recording paper is detected and the paper end position regulation is performed. The paper width of the recording paper can be detected by obtaining the distance between the paper end on one end contacting the portion and the paper end on the other end.
Japanese Patent Application Laid-Open No. 07-179248 Japanese Patent Laid-Open No. 03-138254

By the way, in general, a reflection type sensor such as a photo interrupter has a light emitting unit and a light receiving unit. Light emitted from the light emitting unit is reflected by an object to be detected, and the reflected light is received by the light receiving unit. The output voltage changes according to the amount of received light.
In such a recording paper detection sensor such as a reflection type sensor, the detection sensitivity is generally lowered due to a decrease in performance of the light emitting unit and the light receiving unit due to secular change or the like. As described above, when detecting the paper edge on the other end side in the main scanning direction of the recording paper, an error occurs in the detected paper edge position due to the decrease in detection sensitivity, and thereby the recording paper The paper width detection accuracy will be reduced. For this reason, when ink is ejected onto recording paper and printing is performed, there is a risk that an error will occur in the margin width in the paper width direction, or ink may be ejected to an area exceeding the actual paper width and the platen may be soiled. It was.

  The present invention has been made in view of such a situation, and the problem is that recording caused by a decrease in detection sensitivity of a recording paper detection sensor that is mounted on a carriage and detects a paper edge in the main scanning direction of the recording paper. This is to reduce the detection error of the paper width.

  In order to achieve the above object, according to a first aspect of the present invention, a recording head that discharges ink on a recording sheet is mounted, and a carriage that is supported so as to reciprocate in the main scanning direction and conveyed in the sub scanning direction. Supporting the vicinity of the recording execution area of the recording paper by the recording head from the surface opposite to the recording surface of the recording paper, and defining the distance between the head surface of the recording head and the recording surface of the recording paper It comprises a light reflection type sensor that has a platen, a light emitting part, and a light receiving part, receives reflected light of the light emitted from the light emitting part, and outputs a detection voltage corresponding to the received light quantity. In the ink jet recording apparatus comprising a recording paper detection sensor mounted on the carriage so as to detect a boundary between the recording paper and the platen, the recording paper width detection detects the paper width of the recording paper in the main scanning direction. A method, The detected portion formed on the surface of the platen that supports the recording paper is detected by the recording paper detection sensor, and the detection sensitivity of the recording paper detection sensor is determined from the detection signal when the detected portion is detected. A recording paper detection threshold value setting step for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity, and a paper sheet on one end side in the main scanning direction of the recording paper A paper edge detection step of detecting a paper edge on the other end side in the main scanning direction of the recording paper with the recording paper detection threshold in a state where the edge is in contact with the paper edge position restricting portion, and a reference for paper width detection From the carriage stop position to the other end side in the main scanning direction until the end of the carriage is detected, the one end side of the recording paper in the main scanning direction and the other end side of the recording paper The main scanning direction of the recording paper And a recording paper width calculation step of calculating the width is a recording paper width detection method, wherein a.

  A light-reflective sensor that has a light-emitting unit and a light-receiving unit, receives reflected light of the light emitted from the light-emitting unit, and outputs a detection voltage according to the received light amount. To detect the recording paper, the output voltage in the state of detecting the recording paper, that is, the output voltage in the amount of light received by the light receiving portion by the reflectance of the surface of the recording paper, and the output voltage in the state of detecting the platen surface, that is, The paper edge of the recording paper is detected from the difference from the output voltage in the amount of light received by the light receiving unit due to the reflectance of the platen surface.

  Considering the possibility of erroneous detection, the threshold is basically set to a voltage approximately halfway between the output voltage when the recording paper is detected and the output voltage when the platen surface is detected. If the voltage is higher than the threshold voltage, it is determined that the platen is detected, that is, the recording paper is not detected. If the voltage is lower than the threshold voltage, it is determined that the recording paper is detected. . Therefore, the detection delay of the recording paper detection sensor is caused by the response delay of the light receiving unit from the time when the edge of the recording paper reaches the detection unit of the recording paper detection sensor until the voltage drops to the threshold value. Due to the delay, an error occurs when detecting the paper edge of the recording paper.

  If the detection delay of the recording paper detection sensor is constant, it is possible to detect the paper edge of the recording paper accurately by correcting the paper edge position accordingly. However, as described above, the reflection type sensor tends to have lower detection sensitivity due to secular change, and as a result, the detection delay of the recording paper detection sensor when detecting the paper edge of the recording paper increases. As described above, since the detection delay of the recording paper detection sensor increases due to secular change, the paper edge detection error of the recording paper by the recording paper detection sensor increases, so that ink is ejected onto the recording paper. When printing is performed, an error occurs in the margin width in the paper width direction, or ink is ejected to an area exceeding the actual paper width and the platen is stained.

  Therefore, first, the detected part formed on the surface of the platen that supports the recording paper is detected by the recording paper detection sensor, and the detection sensitivity of the recording paper detection sensor is determined from the detection signal when this detected part is detected. To do. That is, the detection sensitivity of the recording paper detection sensor can be known from the detected voltage by detecting the invariable detected portion formed on the platen with the recording paper detection sensor.

  Subsequently, the recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity is set. In this way, each recording paper detection threshold is set so that the detection delay time of the recording paper detection sensor is the same when the detection sensitivity is high and when the detection sensitivity is reduced due to aging. can do. That is, if the recording paper detection threshold is not intermediate between the output voltage when the recording paper is detected and the output voltage when the platen surface is detected, and the detection sensitivity is high, the recording paper If the detection sensitivity is low, the recording paper detection threshold is set near the output voltage when the platen surface is detected. By doing so, the detection delay time of the recording paper detection sensor can be made the same in the case where the detection sensitivity is high and in the case where the detection sensitivity is lowered due to secular change.

  Thus, by setting the recording paper detection threshold value in accordance with the detection sensitivity of the recording paper detection sensor, even if the detection sensitivity of the recording paper detection sensor changes, the edge of the recording paper due to the delay of the recording paper detection sensor. It is possible to make the error in detecting the substantially constant. Since the influence of the detection sensitivity of the recording paper detection sensor can be reduced by correcting the paper edge position of the recording paper by the error, it is possible to detect the paper edge of the recording paper with high accuracy. It becomes possible.

  Thus, according to the recording paper width detection method described in the first aspect of the present invention, it is possible to reduce the influence of the detection sensitivity of the recording paper detection sensor, and to detect the paper edge of the recording paper with high accuracy. As a result, it is possible to reduce the detection error of the recording paper width caused by the decrease in the detection sensitivity of the recording paper detection sensor.

  According to a second aspect of the present invention, in the first aspect described above, the recording paper detection threshold setting step sets the recording paper detection threshold to a value that reflects the recording surface when ink is ejected from the recording head. The recording paper width detection method is characterized in that a voltage higher than the output voltage of the recording paper detection sensor when detecting the recording paper in a recording execution state where the rate is assumed to be the lowest is set.

  When detecting the recording surface of the recording paper on which recording has been performed by ejecting ink, such as when the recording paper detection sensor is disposed downstream of the recording head in the sub-scanning direction, the recording surface in an unrecorded white state As a result, the reflectance of light decreases. Therefore, when the recording paper detection threshold is set to a value close to the detection voltage in the state where the unrecorded recording surface is detected, the detection voltage is set to the recording paper even though the recording paper is detected. There is a possibility that the detection threshold value is not reached. Therefore, in this case, even if the recording paper is detected, it is determined that the recording paper is not detected, and the recording paper may not be detected.

  Therefore, by setting the recording paper detection threshold to a voltage higher than the output voltage of the recording paper detection sensor when detecting the recording paper on which the reflectance of the recording surface is assumed to be the lowest when ink is ejected, It is possible to eliminate the possibility that the detection voltage does not reach the recording paper detection threshold even though the recording paper is being detected.

  Thus, according to the recording paper width detection method described in the second aspect of the present invention, in addition to the operational effects of the invention described in the first aspect described above, the recording paper that has been subjected to recording by ejecting ink is recorded. When detecting the recording surface, it is possible to eliminate the possibility that the detection voltage does not reach the recording paper detection threshold even though the recording paper is being detected. The effect that can be detected is obtained. It should be noted that a certain voltage width is present between the output voltage of the recording paper detection sensor when detecting the recording paper on which the reflectance of the recording surface is assumed to be the lowest when the ink is ejected and the recording paper detection threshold value. Needless to say, it is possible to detect the end of the recording sheet more reliably by providing a certain margin.

  According to a third aspect of the present invention, in the first aspect or the second aspect described above, the recording paper detection threshold value setting step includes a paper edge detection error of the recording paper due to a detection delay of the recording paper detection sensor. The recording paper detection threshold value is set in correspondence with the detection sensitivity of the recording paper detection sensor determined from the detection signal when the detected portion is detected so that a constant error amount is obtained. This is a recording paper width detection method.

  In this way, the recording paper detection threshold is set so that the paper edge detection error of the recording paper due to the detection delay of the recording paper detection sensor becomes a constant error amount. By correcting the paper edge position, it is possible to detect the paper edge of the recording paper without being affected by the detection sensitivity of the recording paper detection sensor.

  Thus, according to the recording paper width detection method according to the third aspect of the present invention, in addition to the operational effects of the invention according to the first aspect or the second aspect described above, the detection delay of the recording paper detection sensor. By setting the recording paper detection threshold so that the paper edge detection error of the recording paper becomes a certain amount of error, it is possible to detect the paper edge of the recording paper without being affected by the detection sensitivity of the recording paper detection sensor. Therefore, the effect of being able to detect the end of the recording paper more accurately is obtained.

  According to a fourth aspect of the present invention, a recording head for ejecting ink is mounted on a recording sheet, the carriage is pivotally supported so as to reciprocate in the main scanning direction, and the recording of the recording sheet conveyed in the sub-scanning direction. A platen that supports the vicinity of the recording execution area by the head from a surface opposite to the recording surface of the recording paper, defines a distance between the head surface of the recording head and the recording surface of the recording paper, a light emitting unit, and a light receiving unit A light reflection type sensor capable of receiving reflected light of the light emitted from the light emitting unit at the light receiving unit and outputting a detection voltage corresponding to the received light amount, the recording paper and the platen And a recording paper detection sensor mounted on the carriage so that the boundary between the recording paper and the recording paper can be detected. The paper edge on the other end side in the main scanning direction is detected on the recording paper. Based on the amount of movement of the carriage in the main scanning direction from the carriage stop position that becomes a reference for paper width detection to the detection of the paper end on the other end side in the main scanning direction. An ink jet recording apparatus comprising: a recording control unit having a recording paper width detecting unit that calculates a paper width of the recording paper in the main scanning direction by calculating a distance between a paper end on one end side and a paper end on the other end side The platen is formed on a surface that supports the recording paper, and has a detected portion that can be detected by the recording paper detection sensor, and the recording control unit has a detection sensitivity of the recording paper detection sensor. The detected portion serving as a reference for determining the detection is detected by the recording paper detection sensor, the detection sensitivity of the recording paper detection sensor is determined from the detection signal when the detected portion is detected, and the determined detection sensitivity is obtained. Corresponding recording paper detection sensor Ink-jet recording, characterized in that a recording paper detection threshold value of the detection voltage is set, and the paper edge on the other end side in the main scanning direction of the recording paper is detected with the set recording paper detection threshold value Device.

  According to the ink jet recording apparatus described in the fourth aspect of the present invention, in the ink jet recording apparatus, the same operational effects as those of the invention described in the first aspect described above can be obtained.

  According to a fifth aspect of the present invention, in the fourth aspect described above, the recording paper detection sensor is disposed downstream of the recording head in the sub-scanning direction, and the recording control unit includes the recording head. When detecting a paper edge in the main scanning direction of the recording paper on which recording has been performed by ejecting ink from the recording paper, the recording paper detection threshold is set to reflect the reflectance of the recording surface after ink is ejected from the recording head. The ink jet recording apparatus is characterized in that the voltage is set to be higher than the output voltage of the recording paper detection sensor when detecting the recording paper in the recording execution state that is assumed to be the lowest.

  According to the ink jet recording apparatus described in the fifth aspect of the present invention, the same effect as that of the invention described in the second aspect described above can be obtained in the ink jet recording apparatus.

  According to a sixth aspect of the present invention, in the fourth aspect or the fifth aspect described above, the recording control unit is configured such that a paper edge detection error of the recording paper due to a detection delay of the recording paper detection sensor is a constant error. The recording sheet detection threshold value is set so as to correspond to the detection sensitivity of the recording sheet detection sensor determined from the detection signal when the detected portion is detected so as to be a quantity. Device.

  According to the ink jet recording apparatus described in the sixth aspect of the present invention, the same effect as that of the invention described in the third aspect described above can be obtained in the ink jet recording apparatus.

  According to a seventh aspect of the present invention, in any one of the fourth to sixth aspects described above, a part of the plurality of ribs formed in parallel to the sub-scanning direction on the surface of the platen that supports the recording paper. The inkjet recording apparatus is characterized in that the detected portion is used as the detected portion.

  A plurality of ribs formed in parallel to the sub-scanning direction on the surface of the platen that supports the recording paper lift the recording paper when the recording paper on which the ink is ejected on the recording surface is undulated by the so-called cockling phenomenon. It is for suppressing. Then, it is necessary to provide a separate detected portion by using a part of the plurality of ribs as the detected portion, that is, by using the existing rib for suppressing the floating of the recording paper due to the cockling phenomenon as the detected portion. Disappear.

  Thereby, according to the ink jet recording apparatus described in the seventh aspect of the present invention, in addition to the function and effect of the invention described in any of the fourth to sixth aspects described above, the existing rib is detected. Since it is not necessary to provide a separate detection part by using the unit, the existing platen can be used as it is in the ink jet recording apparatus, and there is an effect that a new manufacturing cost according to the present invention does not occur. It is done.

  According to an eighth aspect of the present invention, in any one of the fourth to seventh aspects described above, the recording paper detection sensor includes the light emitting unit including a light emitting diode and the light receiving unit including a phototransistor. An ink jet recording apparatus characterized by being a photointerrupter.

  As described above, the present invention can also be implemented in an ink jet recording apparatus using a generally known reflection type photo interrupter as a recording paper detection sensor, and is described in any of the fourth to seventh aspects described above. The effect by this invention can be acquired.

  According to a ninth aspect of the present invention, there is provided a recording head that ejects ink onto a recording sheet, a carriage that is pivotally supported so as to be reciprocable in the main scanning direction, and the recording of the recording sheet that is conveyed in the sub-scanning direction. A platen that supports the vicinity of the recording execution area by the head from a surface opposite to the recording surface of the recording paper, defines a distance between the head surface of the recording head and the recording surface of the recording paper, a light emitting unit, and a light receiving unit A light reflection type sensor capable of receiving reflected light of the light emitted from the light emitting unit at the light receiving unit and outputting a detection voltage corresponding to the received light amount, the recording paper and the platen Recording paper width detection control for causing a computer to execute control for detecting the paper width in the main scanning direction of the recording paper in an ink jet recording apparatus including a recording paper detection sensor mounted on the carriage so as to detect a boundary with the carriage The And detecting the detected portion formed on the surface of the platen that supports the recording paper by the recording paper detection sensor and the detection signal when the detected portion is detected. A procedure for determining the detection sensitivity of the detection sensor, a procedure for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity, and one end side of the recording paper in the main scanning direction And a paper width detection reference for detecting a paper edge on the other end side in the main scanning direction of the recording paper with the recording paper detection threshold in a state where the paper edge is in contact with the paper edge position restricting portion, From the amount of movement of the carriage from the carriage stop position to the detection of the paper end on the other end side in the main scanning direction, the paper end on the one end side in the main scanning direction and the other end side of the recording paper The main run of the recording paper is calculated by calculating the distance from the paper edge And a procedure for calculating the paper width direction, it is recorded paper width detection control program characterized.

  According to the recording paper width detection control program described in the ninth aspect of the present invention, the same operation effect as the invention described in the first aspect described above can be obtained, and this recording paper width detection control program is executed. The same effects as those of the invention described in the first aspect described above can be brought to any ink jet recording apparatus that can be used.

  According to a tenth aspect of the present invention, in the ninth aspect described above, the procedure for setting the recording paper detection threshold value is the recording paper detection threshold value on which a recording surface is formed by ejecting ink from the recording head. The recording paper width detection control program is characterized in that it is set to a voltage higher than the output voltage of the recording paper detection sensor when detecting the recording paper in the recording execution state that is assumed to have the lowest reflectance.

  According to the recording paper width detection control program described in the tenth aspect of the present invention, the same effect as that of the invention described in the second aspect described above can be obtained, and this recording paper width detection control program is executed. The same effects as those of the invention described in the second aspect described above can be brought to any ink jet recording apparatus that can be used.

  According to an eleventh aspect of the present invention, in the ninth aspect or the tenth aspect described above, the procedure for setting the recording paper detection threshold is a paper edge of the recording paper due to a detection delay of the recording paper detection sensor. Setting the recording paper detection threshold value corresponding to the detection sensitivity of the recording paper detection sensor determined from the detection signal when the detected portion is detected, so that the detection error becomes a constant error amount; Is a recording paper width detection control program characterized by the above.

  According to the recording paper width detection control program described in the eleventh aspect of the present invention, the same effect as that of the invention described in the third aspect described above can be obtained, and the recording paper width detection control program is executed. The same operational effects as those of the invention described in the third aspect described above can be brought to any ink jet recording apparatus that can be used.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a schematic configuration of the ink jet recording apparatus according to the present invention will be described. FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side view of an essential part.

  The ink jet recording apparatus 50 has a carriage guide shaft 61 and a sub-carriage guide as recording execution means for executing recording by ejecting ink onto the recording surface while reciprocating on the recording surface of the recording paper P in the main scanning direction X. A carriage 62 that is supported by the shaft 61S so as to be reciprocally movable in the main scanning direction X is disposed. A recording head 63 that ejects ink onto the recording paper P is mounted on the carriage 62. A platen 53 that defines the distance between the head surface of the recording head 63 and the recording paper P is provided facing the recording head 63. An operation of ejecting ink from the head surface of the recording head 63 to the recording paper P while reciprocating the carriage 62 in the main scanning direction X, and an operation of conveying the recording paper P by a predetermined conveyance amount in the sub-scanning direction Y. By alternately repeating the above, recording is performed on the recording paper P.

  A recording sheet detection sensor 64 capable of detecting the recording sheet P on the platen 53 is mounted on the carriage 62 at a position facing the recording surface of the recording sheet P. The recording paper detection sensor 64 is disposed upstream of the recording head 63 in the sub-scanning direction Y. When the carriage 62 is reciprocated in the main scanning direction X, the recording paper detection sensor 64 starts from the recording execution area of the recording head 63 in the sub-scanning direction. This is a sensor capable of detecting the recording paper P on the upstream side of Y. The recording paper detection sensor 64 has a light emitting unit composed of a light emitting diode and a light receiving unit composed of a phototransistor, and light emitted from the light emitting unit is reflected by the recording paper P or platen 53 to be detected and reflected. Is a reflection type photointerrupter having a configuration in which the output voltage changes according to the amount of received light.

  The ink jet recording apparatus 50 includes a paper feed tray 70 on which a large number of recording papers P can be stacked. A paper feed roller 71 is disposed downstream of the paper feed tray 70 in the sub-scanning direction Y. A hopper 72 and a separation pad 73 are disposed in the paper feed tray 70. The recording paper P stacked on the paper feed tray 70 is pressed against the paper feed roller 71 by the hopper 72, and the paper feed tray 71 is driven by the rotation of the paper feed roller 71 in the paper feed direction and the frictional resistance of the separation pad 73. Only the uppermost recording paper P stacked on the recording paper P is separated and automatically fed.

  Further, the ink jet recording apparatus 50 is provided with a transport driving roller 51 and a transport driven roller 52 that intermittently transport the automatically fed recording paper P in the sub-scanning direction Y. The conveyance driving roller 51 is rotationally controlled by a rotational driving force source, and the recording paper P is conveyed in the sub-scanning direction Y by the rotation of the conveyance driving roller 51. A plurality of conveyance driven rollers 52 are provided, and each is individually urged by the conveyance driving roller 51. When the recording paper P is conveyed by the rotation of the conveyance driving roller 51, the conveyance driven roller 52 contacts the recording paper P by the urging force. In the state, the recording paper P is driven to rotate.

  Further, the ink jet recording apparatus 50 is provided with a paper discharge driving roller 54 and a paper discharge driven roller 55 for discharging the recording paper P after execution of recording. The paper discharge driving roller 54 is rotationally controlled by a rotational driving force source, and the recording paper P after recording is discharged in the sub-scanning direction Y by the rotation of the paper discharge driving roller 54. The paper discharge driven roller 55 is a toothed roller having a plurality of teeth around it and sharply sharpened so that the tip of each tooth makes point contact with the recording surface of the recording paper P. The paper discharge driven rollers 55 are individually urged to the paper discharge drive rollers 54 by a biasing force that is weaker than the biasing force of the transport driven roller 52 described above, and the recording paper P is discharged by the rotation of the paper discharge drive rollers 54. When the recording paper P is in contact with the recording paper P by the urging force, the recording paper P is driven to rotate. Then, the recording paper P after execution of recording is discharged downstream in the sub-scanning direction Y by the paper discharge driving roller 54 and the paper discharge driven roller 55. On the downstream side of the paper discharge driving roller 54 and the paper discharge driven roller 55, a paper discharge tray 81 for discharging the recording paper P that has been recorded is disposed.

  Further, the ink jet recording apparatus 50 includes a recording control unit (not shown). The recording control unit has a control function of the ink jet recording apparatus 50 by computer control. The recording control unit inputs various state information of the ink jet recording apparatus 50, and drives and controls each drive system based on the various state information. The ink jet recording apparatus 50 feeds the recording sheets P stacked on the sheet feeding tray 70 under the control of the recording control unit, and reciprocates the carriage 62 in the main scanning direction X while ejecting ink from the recording head 63. The operation of carrying out the recording and the operation of conveying the recording paper P in the sub-scanning direction Y by a predetermined conveyance amount are alternately repeated, and recording is performed on the recording surface of the recording paper P and discharged.

  The recording control unit includes the recording sheet width detecting unit according to the present invention, and the recording sheet width detecting control procedure in the recording sheet width detecting unit will be described. FIG. 3 is a plan view of an essential part of the ink jet recording apparatus 50 according to the present invention.

  When the recording paper P is set in the paper feed tray 70, the ink jet recording apparatus 50 causes the paper end PS1 on one end side in the main scanning direction X of the recording paper P to contact the guide portion 72 of the paper feed tray 70. It is set in the state. For this reason, the paper edge PS1 of the recording paper P is in a state where the paper edge position is always regulated while being in contact with the guide portion 72 regardless of the paper width of the recording paper P. Accordingly, in order to detect the paper width of the recording paper P, only the paper edge PS2 on the other end side in the main scanning direction X of the recording paper P needs to be detected by the recording paper detection sensor 64. That is, the carriage 62 is moved from the reference position indicated by the broken line in the direction indicated by the symbol X1, and the amount of movement of the carriage 62 until the paper end PS2 is detected is driven by a stepping motor or the like that drives the carriage 62. By obtaining from the control amount of the source, the length from the paper edge PS1 to the paper edge PS2, that is, the paper width of the recording paper P can be calculated.

  FIG. 4 is a graph schematically showing the relationship between the output voltage of the recording paper detection sensor 64 and the recording paper P when the paper edge PS2 of the recording paper P is detected. The voltage shown in FIG.

  The vertical axis of the graph is the output voltage of the recording paper detection sensor 64. The voltage indicated by symbol L is an output voltage in a state where the recording paper P is detected (hereinafter referred to as recording paper detection voltage L), and the voltage indicated by symbol H does not detect the recording paper P. This is an output voltage in a state where the platen 53 is detected (hereinafter referred to as a platen detection voltage H). A voltage indicated by a symbol S is a threshold voltage when the recording paper P is detected (hereinafter referred to as a recording paper detection threshold S).

  The graph of the output voltage of the recording paper detection sensor 64 indicated by symbol A shows the recording paper when the platen 53 is detected from the state in which the recording paper P is detected, that is, when the recording paper P passes the paper edge PS2. This shows the period from the detection voltage L to the platen detection voltage H. The output voltage of the recording paper detection sensor 64 has a certain detection delay as shown in the figure depending on its response performance. Therefore, after passing through the paper edge PS2 of the recording paper P, until the recording paper detection voltage L reaches the recording paper detection threshold value S, the paper indicated by the symbol D due to the detection delay of the recording paper detection sensor 64 An edge detection error occurs, and the position of the sheet edge PS2 of the recording sheet P is shifted accordingly.

  If the paper edge detection error indicated by the symbol D is constant, the paper edge PS2 can be detected accurately by correcting the position of the paper edge PS2 accordingly. However, the recording paper detection sensor 64 has a characteristic that the detection sensitivity gradually decreases with the passage of time, as described above, in addition to variations in individual characteristics. The graph indicated by symbol A shows the output voltage characteristic when the detection sensitivity of the recording paper detection sensor 64 is the best, that is, when it is new, and the graph indicated by symbol C shows the detection sensitivity of the recording paper detection sensor 64. Shows the output voltage characteristic when the voltage drops most, i.e., when it becomes old after a long period of time, and the graph indicated by the symbol B shows an intermediate state.

  That is, the same recording paper detection threshold value S in the state in which the detection sensitivity of the recording paper detection sensor 64 indicated by symbol A is the best and in the state in which the detection sensitivity of the recording paper detection sensor 64 indicated by symbol C is the lowest. When the paper end PS2 of the recording paper P is detected, an error corresponding to the symbol E is generated in addition to the paper end detection error D described above. Therefore, as the detection sensitivity of the recording paper detection sensor 64 decreases due to secular change, the detection accuracy of the paper edge PS2 of the recording paper P decreases.

  FIG. 5 is a graph schematically showing the relationship between the output voltage of the recording paper detection sensor 64 and the recording paper P when the ribs R formed on the platen 53 are detected.

  The graphs indicated by reference signs A, B, and C are the same as the graph shown in FIG. 4, and the graph indicated by reference sign A is the graph indicated by reference sign C in the state in which the recording paper detection sensor 64 has the best detection sensitivity. Indicates a state in which the detection sensitivity of the recording paper detection sensor 64 is the lowest, and a graph indicated by symbol B indicates an intermediate state. First, a part of the rib R formed on the platen 53 as a detected portion is detected by the main scanning operation of the carriage 62. Then, the voltage waveform when the rib R is detected differs depending on the detection sensitivity of the recording paper detection sensor 64. In this embodiment, since the rib R has a narrow width in the main scanning direction X, the detection time by the recording paper detection sensor 64 is short. For this reason, during the main scanning operation of the carriage 62, the recording paper detection sensor 64 is separated from the rib R before the detection voltage drops to a certain voltage, so that the detection voltage of the recording paper detection sensor 64 increases from that point. It will be.

  Therefore, the lowest voltage value of the detection voltage when the rib R is detected by the main scanning operation of the carriage 62 differs depending on the detection sensitivity of the recording paper detection sensor 64 as shown by the voltage values V1, V2, and V3. Value. Therefore, the detection sensitivity of the recording paper detection sensor 64 can be determined by detecting the rib R by the main scanning operation of the carriage 62. In the embodiment, the rib R is used for the detected portion. However, a detected portion that can be detected by the recording paper detection sensor 64 may be provided on the platen 53 separately. It is possible to implement the present invention in the aspect.

  FIG. 6 is a graph schematically showing the relationship between the output voltage of the recording paper detection sensor 64 and the recording paper P when the paper edge PS2 of the recording paper P is detected, and the recording paper detection threshold value is denoted by S1. To the voltage indicated by symbol S3.

  The recording paper detection threshold values S1, S2, and S3 are recording paper detection threshold values corresponding to the voltage values V1, V2, and V3 shown in FIG. When the voltage value when the rib R is detected by the recording paper detection sensor 64 by the main scanning operation of the carriage 62 is a voltage value (voltage value V1) higher than a predetermined voltage value, the detection by the recording paper detection sensor 64 is performed. It is determined that the sensitivity is high, and the recording paper detection threshold is set to a high voltage value (recording paper detection threshold S1). As a result, the voltage difference between the recording paper detection voltage L and the recording paper detection threshold value becomes large, so that the recording paper detection threshold value is a substantially intermediate voltage between the recording paper detection voltage L and the platen detection voltage H. Compared to the case where the value is set, the time from the recording paper detection voltage L to the recording paper detection threshold value S1 becomes longer.

  On the other hand, when the voltage value when the recording paper detection sensor 64 detects the rib R by the main scanning operation of the carriage 62 is a voltage value (voltage value V3) lower than a predetermined voltage value, the recording paper detection sensor 64 is used. Is determined to be in a low state, and the recording paper detection threshold is set to a low voltage value (recording paper detection threshold S3). As a result, the voltage difference between the recording sheet detection voltage L and the recording sheet detection threshold value is reduced, so that the recording sheet detection threshold value is a substantially intermediate voltage between the recording sheet detection voltage L and the platen detection voltage H. Compared to the case of the value, the time from the recording paper detection voltage L to the recording paper detection threshold S1 is shortened. If the voltage value when the recording paper detection sensor 64 detects the rib R by the main scanning operation of the carriage 62 is the intermediate voltage value V2, the recording paper detection threshold value S1 and the recording paper detection threshold value are detected. The recording sheet detection threshold value S2 is set approximately in the middle of S3.

  In this way, when the detection sensitivity of the recording paper detection sensor 64 is high in correspondence with the detection sensitivity of the recording paper detection sensor 64, the recording paper detection threshold is set high, and the detection sensitivity of the recording paper detection sensor 64 is set. Is low, the recording paper detection threshold is set low. As a result, the output voltage of the recording paper detection sensor 64 reaches the recording paper detection threshold from the time when the paper edge PS2 of the recording paper P passes the recording paper detection sensor 64, and the paper edge PS2 detects. The paper edge detection error D due to the detection delay of the recording paper detection sensor 64 can be made constant.

  That is, the voltage value when the rib R is detected by the recording paper detection sensor 64 by the main scanning operation of the carriage 62 changes with the passage of time between V1 and V3, and corresponds to the voltage value. By shifting the recording paper detection threshold value between S1 and S3, the paper edge detection error D due to the detection delay of the recording paper detection sensor 64 can be made constant. Therefore, an error due to a decrease in the detection sensitivity of the recording paper detection sensor 64 as indicated by reference numeral E in FIG. 4 does not occur.

  In this way, it is possible to reduce the detection error of the paper width of the recording paper P caused by the decrease in the detection sensitivity of the recording paper detection sensor 64.

  In another embodiment, the recording paper detection sensor 64 is disposed downstream of the recording head 63 in the sub-scanning direction Y. In such an ink jet recording apparatus 50, the recording surface of the recording paper P after ink is ejected from the recording head 63 is detected by the recording paper detection sensor 64. For this reason, the reflectance of the recording surface of the recording paper P decreases as ink is ejected, so the detection voltage of the recording surface is lower than the recording paper detection voltage L when an unrecorded recording surface is detected. Get higher.

  FIG. 7 schematically shows the relationship between the output voltage of the recording paper detection sensor 64 and the recording paper P when detecting the paper edge PS2 of the recording paper P in another embodiment of the ink jet recording apparatus 50 according to the present invention. In this graph, the recording paper detection threshold is set to the voltage indicated by reference signs S1 to S3.

  The voltage value indicated by the symbol F is the maximum voltage value of the recording surface detection voltage L on the recording surface on which ink is ejected (hereinafter referred to as a recorded recording surface detection voltage F). That is, the voltage value when a recording surface in which ink is ejected and the reflectance is lowest is detected. Therefore, the recording paper detection threshold value S3 when the detection sensitivity of the recording paper detection sensor 64 is low is a voltage value lower than the recorded recording surface detection voltage F, and is determined by the recording paper detection threshold value S3. There is a possibility that the recording paper P cannot be detected.

  Therefore, the recording paper detection threshold value S3 needs to be higher than the recorded recording surface detection voltage F. Ideally, as shown in FIG. 6, it is desirable that the paper edge detection error D due to the detection delay of the recording paper detection sensor 64 is constant within the fluctuation range of the detection sensitivity of the recording paper detection sensor 64. However, when the paper end PS2 of the recorded recording surface is detected by the recording paper detection sensor 64 as in the present embodiment, the code in FIG. 4 is within the variation range of the detection sensitivity of the recording paper detection sensor 64. In some cases, an error due to a decrease in the detection sensitivity of the recording paper detection sensor 64 as indicated by E must be allowed in a possible range.

  FIG. 8 schematically shows the relationship between the output voltage of the recording paper detection sensor 64 and the recording paper P when detecting the paper edge PS2 of the recording paper P in another embodiment of the ink jet recording apparatus 50 according to the present invention. In this graph, the recording paper detection threshold is set to the voltages indicated by reference numerals S1, S4, and S5.

  In order to eliminate the possibility that the recording paper P cannot be detected at the recording paper detection threshold value S3 in the state where the detection sensitivity of the recording paper detection sensor 64 is the lowest, the recording paper detection threshold value S3 is most reflected when ink is ejected. It is set to a voltage value (recording paper detection threshold S5) obtained by adding a certain margin voltage G to the recorded recording surface detection voltage F as a voltage value when a recording surface with a low rate is detected. When the detection sensitivity of the recording paper detection sensor 64 indicated by the symbol B is a substantially intermediate detection sensitivity, the recording paper detection threshold value is the recording paper detection threshold value S1 and the recording paper detection threshold value S5. The recording sheet detection threshold value S4 is intermediate between the two. Then, by shifting the recording paper detection threshold value between S1 and S5, in addition to the paper edge detection error D due to the detection delay of the recording paper detection sensor 64, an error E due to a decrease in detection sensitivity of the recording paper detection sensor 64 is obtained. However, the error amount is sufficiently smaller than the error E that occurs when the recording paper detection threshold value shown in FIG. Is negligible.

  In this manner, in the ink jet recording apparatus 50 in which the recording paper detection sensor 64 is disposed on the downstream side in the sub-scanning direction Y from the recording head 63, an error E occurs due to a decrease in detection sensitivity of the recording paper detection sensor 64. However, the error amount E can be sufficiently small so that the influence on the recording image quality can be ignored. Accordingly, it is possible to reduce a decrease in detection accuracy of the paper edge PS2 due to a decrease in detection sensitivity of the recording paper detection sensor 64.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

  According to the present invention, it is possible to reduce the detection error of the paper width of the recording paper caused by the decrease in the detection sensitivity of the recording paper detection sensor that is mounted on the carriage and detects the paper edge of the recording paper in the main scanning direction.

1 is a perspective view showing an embodiment of an ink jet recording apparatus according to the present invention. It is the principal part side view which showed one Embodiment of the inkjet type recording apparatus which concerns on this invention. It is a principal part top view of the ink jet recording device concerning the present invention. It is the graph which showed typically the relationship between the output voltage of a recording paper detection sensor at the time of detecting the paper edge of a recording paper, and a recording paper, and made the recording paper detection threshold value into the voltage shown with the code. . 6 is a graph schematically showing a relationship between an output voltage of a recording paper detection sensor and recording paper when detecting a rib formed on the platen. It is a graph schematically showing the relationship between the output voltage of the recording paper detection sensor and the recording paper when detecting the edge of the recording paper, and the recording paper detection threshold corresponding to the detection sensitivity of the recording paper detection sensor. Is set. It is a graph schematically showing the relationship between the output voltage of the recording paper detection sensor and the recorded recording paper when detecting the paper edge of the recording paper, and detecting the recording paper corresponding to the detection sensitivity of the recording paper detection sensor. A threshold is set. In FIG. 7, the recording paper detection threshold is set corresponding to the detection sensitivity of the recording paper detection sensor so that the end of the recording paper can be detected even when the detection sensitivity is the lowest.

Explanation of symbols

50 Inkjet recording apparatus, 51 Conveyance drive roller, 52 Conveyance driven roller, 53 Platen, 54 Discharge drive roller, 55 Discharge driven roller, 56 Discharge frame, 57 holes, 61 Carriage guide shaft, 61S Subcarriage guide shaft, 62 Carriage, 63 Recording head, 64 Recording paper detection sensor, 70 Paper feed tray, 71 Paper feed roller, 72 Hopper, 73 Separation pad, 81 Paper discharge tray, H Platen detection voltage, L Recording paper detection voltage, P Recording paper, S Recording paper detection threshold, X main scanning direction, Y sub-scanning direction

Claims (7)

A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. In the ink jet recording apparatus comprising a recording paper detection sensor mounted on the recording paper, a recording paper width detection method for detecting a paper width in the main scanning direction of the recording paper,
The detected portion formed on the surface of the platen that supports the recording paper is detected by the recording paper detection sensor, and the detection sensitivity of the recording paper detection sensor is determined from the detection signal when the detected portion is detected. A recording paper detection threshold value setting step for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity;
In the state where the paper end on one end side in the main scanning direction of the recording paper is in contact with the paper end position restricting portion, the paper end on the other end side in the main scanning direction of the recording paper is set as the recording paper detection threshold value. A paper edge detection process to detect in
Based on the amount of movement of the carriage from the carriage stop position serving as a reference for paper width detection to the detection of the paper end on the other end side in the main scanning direction, the paper end on the one end side in the main scanning direction of the recording paper And a recording paper width calculation step of calculating a paper width in the main scanning direction of the recording paper by calculating an interval between the paper edge on the other end side,
The recording paper detection threshold value setting step is based on a detection signal when the detected portion is detected so that a paper edge detection error of the recording paper due to a detection delay of the recording paper detection sensor becomes a constant error amount. A recording sheet width detection method, wherein the recording sheet detection threshold value is set in correspondence with the determined detection sensitivity of the recording sheet detection sensor. A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. In the ink jet recording apparatus comprising a recording paper detection sensor mounted on the recording paper, a recording paper width detection method for detecting a paper width in the main scanning direction of the recording paper,
The detected portion formed on the surface of the platen that supports the recording paper is detected by the recording paper detection sensor, and the detection sensitivity of the recording paper detection sensor is determined from the detection signal when the detected portion is detected. A recording paper detection threshold value setting step for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity;
In the state where the paper end on one end side in the main scanning direction of the recording paper is in contact with the paper end position restricting portion, the paper end on the other end side in the main scanning direction of the recording paper is set as the recording paper detection threshold value. A paper edge detection process to detect in
Based on the amount of movement of the carriage from the carriage stop position serving as a reference for paper width detection to the detection of the paper end on the other end side in the main scanning direction, the paper end on the one end side in the main scanning direction of the recording paper And a recording paper width calculation step of calculating a paper width in the main scanning direction of the recording paper by calculating an interval between the paper edge on the other end side,
In the recording paper detection threshold value setting step, the detection time when the detected portion is detected by the recording paper detection sensor while moving the carriage in the main scanning direction is the detection voltage of the recording paper detection sensor. A recording paper width detection method characterized in that the recording paper detection sensor is set at a time when the recording paper detection sensor moves away from the detected portion before dropping to a certain voltage. A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. The recording paper detection sensor mounted on the recording paper and the paper edge on one end side in the main scanning direction of the recording paper are in contact with the paper edge position restricting portion, The paper edge is detected by the recording paper detection threshold, and the paper width From the amount of movement of the carriage from the carriage stop position serving as a reference to the detection until the paper end on the other end side in the main scanning direction is detected, the paper end on the one end side in the main scanning direction of the recording paper, An ink jet recording apparatus comprising: a recording control unit having a recording paper width detecting unit that calculates a paper width in the main scanning direction of the recording paper by calculating a distance between the paper end on the other end side,
The platen is formed on a surface that supports the recording paper, and has a detected portion that can be detected by the recording paper detection sensor,
The recording control unit detects the detected portion serving as a reference for determining the detection sensitivity of the recording paper detection sensor by the recording paper detection sensor, and detects the recording paper from a detection signal when the detected portion is detected. The detection sensitivity of the detection sensor is determined, a recording sheet detection threshold value of the detection voltage of the recording sheet detection sensor corresponding to the determined detection sensitivity is set, and the main recording sheet detection threshold is set at the set recording sheet detection threshold value. Detect the paper end on the other end in the scanning direction,
The detection sensitivity of the recording paper detection sensor determined from the detection signal when the detected portion is detected so that the paper edge detection error of the recording paper due to the detection delay of the recording paper detection sensor becomes a constant error amount. An ink jet recording apparatus, wherein the recording paper detection threshold value is set correspondingly. A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. The recording paper detection sensor mounted on the recording paper and the paper edge on one end side in the main scanning direction of the recording paper are in contact with the paper edge position restricting portion, The paper edge is detected by the recording paper detection threshold, and the paper width From the amount of movement of the carriage from the carriage stop position serving as a reference to the detection until the paper end on the other end side in the main scanning direction is detected, the paper end on the one end side in the main scanning direction of the recording paper, An ink jet recording apparatus comprising: a recording control unit having a recording paper width detecting unit that calculates a paper width in the main scanning direction of the recording paper by calculating a distance between the paper end on the other end side,
The platen is formed on a surface that supports the recording paper, and has a detected portion that can be detected by the recording paper detection sensor,
The recording control unit detects the detected portion serving as a reference for determining the detection sensitivity of the recording paper detection sensor by the recording paper detection sensor, and detects the recording paper from a detection signal when the detected portion is detected. The detection sensitivity of the detection sensor is determined, a recording sheet detection threshold value of the detection voltage of the recording sheet detection sensor corresponding to the determined detection sensitivity is set, and the main recording sheet detection threshold is set at the set recording sheet detection threshold value. Detect the paper end on the other end in the scanning direction,
The detection time when the detected portion is detected by the recording paper detection sensor while moving the carriage in the main scanning direction before the detection voltage of the recording paper detection sensor drops to a certain voltage. An ink jet recording apparatus, characterized in that the detection sensor is set at a time away from the detected portion.   5. The ink jet recording apparatus according to claim 3, wherein the recording paper detection sensor is a reflective photointerrupter having the light emitting unit made of a light emitting diode and the light receiving unit made of a phototransistor. A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. A recording paper width detection control program for causing a computer to execute control for detecting the paper width of the recording paper in the main scanning direction.
A procedure for detecting a detected portion formed on a surface of the platen that supports the recording paper by the recording paper detection sensor;
A procedure for determining the detection sensitivity of the recording paper detection sensor from the detection signal when the detected portion is detected;
A procedure for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity;
In the state where the paper end on one end side in the main scanning direction of the recording paper is in contact with the paper end position restricting portion, the paper end on the other end side in the main scanning direction of the recording paper is set as the recording paper detection threshold value. Steps to detect in
A paper edge on one end side in the main scanning direction of the recording paper is determined from a movement amount of the carriage from a carriage stop position serving as a reference for paper width detection to detection of a paper end on the other end side in the main scanning direction. And calculating a paper width in the main scanning direction of the recording paper by calculating an interval between the paper edge on the other end side,
The procedure for setting the recording paper detection threshold is the detection when the detected portion is detected so that the paper edge detection error of the recording paper due to the detection delay of the recording paper detection sensor becomes a constant error amount. A recording paper width detection control program, wherein the recording paper detection threshold value is set in correspondence with the detection sensitivity of the recording paper detection sensor determined from the signal. A recording head for ejecting ink is mounted on the recording paper, and a carriage that is pivotally supported so as to reciprocate in the main scanning direction and a recording execution area near the recording execution area of the recording paper conveyed in the sub-scanning direction are recorded. A platen for supporting a distance between a head surface of the recording head and a recording surface of the recording paper, a light emitting unit, and a light receiving unit, which are supported from a surface opposite to the recording surface of the paper; The carriage includes a light reflection type sensor capable of receiving reflected light of light emitted from the light receiving unit and outputting a detection voltage corresponding to the received light quantity, and capable of detecting a boundary between the recording paper and the platen. A recording paper width detection control program for causing a computer to execute control for detecting the paper width of the recording paper in the main scanning direction.
A procedure for detecting a detected portion formed on a surface of the platen that supports the recording paper by the recording paper detection sensor;
A procedure for determining the detection sensitivity of the recording paper detection sensor from the detection signal when the detected portion is detected;
A procedure for setting a recording paper detection threshold value of the detection voltage of the recording paper detection sensor corresponding to the determined detection sensitivity;
In the state where the paper end on one end side in the main scanning direction of the recording paper is in contact with the paper end position restricting portion, the paper end on the other end side in the main scanning direction of the recording paper is set as the recording paper detection threshold value. Steps to detect in
A paper edge on one end side in the main scanning direction of the recording paper is determined from a movement amount of the carriage from a carriage stop position serving as a reference for paper width detection to detection of a paper end on the other end side in the main scanning direction. And calculating a paper width in the main scanning direction of the recording paper by calculating an interval between the paper edge on the other end side,
The procedure for setting the recording paper detection threshold is that the detection time when the detected portion is detected by the recording paper detection sensor while moving the carriage in the main scanning direction is detected by the recording paper detection sensor. A recording paper width detection control program characterized in that the recording paper detection sensor is set at a time when the recording paper detection sensor leaves the detected portion before the voltage drops to a constant voltage.

Images